Ligthart, J.M.R.

In vivo comparison of arterial lumen dimensions assessed by co-registered three-dimensional (3D) quantitative coronary angiography, intravascular ultrasound and optical coherence tomography (Article)

2012-01-19T00:00:00Z

This study sought to compare lumen dimensions as assessed by 3D quantitative coronary angiography (QCA) and by intravascular ultrasound (IVUS) or optical coherence tomography (OCT), and to assess the association of the discrepancy with vessel curvature. Coronary lumen dimensions often show discrepancies when assessed by X-ray angiography and by IVUS or OCT. One source of error concerns a possible mismatch in the selection of corresponding regions for the comparison. Therefore, we developed a novel, real-time co-registration approach to guarantee the point-to-point correspondence between the X-ray, IVUS and OCT images. A total of 74 patients with indication for cardiac catheterization were retrospectively included. Lumen morphometry was performed by 3D QCA and IVUS or OCT. For quantitative analysis, a novel, dedicated approach for co-registration and lumen detection was employed allowing for assessment of lumen size at multiple positions along the vessel. Vessel curvature was automatically calculated from the 3D arterial vessel centerline. Comparison of 3D QCA and IVUS was performed in 519 distinct positions in 40 vessels. Correlations were r = 0.761, r = 0.790, and r = 0.799 for short diameter (SD), long diameter (LD), and area, respectively. Lumen sizes were larger by IVUS (P < 0.001): SD, 2.51 ± 0.58 mm versus 2.34 ± 0.56 mm; LD, 3.02 ± 0.62 mm versus 2.63 ± 0.58 mm; Area, 6.29 ± 2.77 mm2versus 5.08 ± 2.34 mm2. Comparison of 3D QCA and OCT was performed in 541 distinct positions in 40 vessels. Correlations were r = 0.880, r = 0.881, and r = 0.897 for SD, LD, and area, respectively. Lumen sizes were larger by OCT (P < 0.001): SD, 2.70 ± 0.65 mm versus 2.57 ± 0.61 mm; LD, 3.11 ± 0.72 mm versus 2.80 ± 0.62 mm; Area 7.01 ± 3.28 mm2versus 5.93 ± 2.66 mm2. The vessel-based discrepancy between 3D QCA and IVUS or OCT long diameters increased with increasing vessel curvature. In conclusion, our comparison of co-registered 3D QCA and invasive imaging data suggests a bias towards larger lumen dimensions by IVUS and by OCT, which was more pronounced in larger and tortuous vessels.

The diagnostic value of intracoronary optical coherence tomography (Article)

2011-07-11T00:00:00Z

Optical coherence tomography (OCT) is a novel light-based imaging modality for application in the coronary circulation. Compared to conventional intravascular ultrasound, OCT has a ten-fold higher image resolution. This advantage has seen OCT successfully applied in the assessment of atherosclerotic plaque, stent apposition, and tissue coverage, heralding a new era in intravascular coronary imaging. The present article discusses the diagnostic value of OCT, both in cardiovascular research as well as in potential clinical application. The unparalleled high image resolution and strong contrast between the coronary lumen and the vessel wall structure enable fast and reliable image interpretation. OCT makes it possible to visualize the presence of atherosclerotic plaque in order to characterize the structure and extent of coronary plaque and to quantify lumen dimensions, as well as the extent of lumen narrowing, in unprecedented detail. Based on optical properties, OCT is able to distinguish different tissue types, such as fibrous, lipid-rich, necrotic, or calcified tissue. Furthermore, OCT is able to cover the visualization of a variety of features of atherosclerotic plaques that have been associated with rapid lesion progression and clinical events, such as thin cap fibroatheroma, fibrous cap thickness, dense macrophage infiltration, and thrombus formation. These unique features allow the use of OCT to assess patients with acute coronary syndrome and to study the dynamic nature of coronary atherosclerosis in vivo and over time. This permits new insights into plaque progression, regression, and rupture, as well as the study of effects of therapies aimed at modulating these developments. Today's OCT technology allows high detail resolution as well as fast and safe clinical image acquisition. These unique features have established OCT as the gold standard for the assessment of coronary stents. This technique makes it possible to study stent expansion, peri-procedural vessel trauma, and the interaction of the stent with the vessel wall down to the level of individual stent struts, both acutely as well as in the long term, where it is has proven extremely sensitive to the detection of even minor amounts of tissue coverage. These qualities render OCT indispensable to addressing vexing clinical questions such as the relationship of drug-eluting stent deployment, vascular healing, the true time course of endothelial stent coverage, and late stent thrombosis. This may also better guide the optimal duration of dual anti-platelet therapy that currently remains unclear and relatively empirical. In the future, OCT might emerge, parallel to its undisputed position in research, as the tool of choice in all clinical scenarios where angiography is limited by its nature as a two-dimensional luminogram.

Comparison of plaque prolapse in consecutive patients treated with Xience V and Taxus Liberte stents (Article)

2010-12-21T00:00:00Z

The purpose of this article is to investigate the prevalence of plaque prolapse (PP) after Xience V and Taxus Liberte stent implantation. During the study period 2006-2007, 200 consecutive patients underwent coronary revascularization for de novo lesions and received an intravascular ultrasound (IVUS) post-stenting evaluation, (n = 124 patients with Taxus Liberte and n = 76 with Xience V) (227 stent segments). Cross-sectional and longitudinal 3D IVUS images were analyzed in a blind fashion, evaluating the prevalence of PP and calculating its depth and angle. The angulation degree of the coronary artery at the lesion site pre-stent implantation was also evaluated by angiography. The prevalence of PP was 23.9% in Xience V versus 38.1% in Taxus Liberte (P = 0.025). The depth and angle of PP were greater in Taxus Liberte stent than Xience V stent (0.4 ± 0.1 mm versus 0.5 ± 0.2 mm, P = 0.004; and 32.0 ± 8.9° versus 44.6 ± 27.6°, P = 0.044, respectively). The angulation degree of the coronary artery at the lesion site was higher in presence of plaque prolapse than in its absence (48.2 ± 29.3° vs. 38.2 ± 28.1°, P = 0.013). By multivariate analysis, stent type was independently associated with incidence of plaque prolapse. Xience V stent has less plaque prolapse than Taxus Liberte stent. Stent design may play a role in the prevalence of plaque prolapse.

Assessment of the serial changes of vessel wall contents in atherosclerotic coronary lesion with bioresorbable everolimus-eluting vascular scaffolds using Shin's method: an IVUS study (Article)

2010-11-16T00:00:00Z

Although serial changes in necrotic core and calcium are regarded as surrogates for the bioresorption process in patients treated with the bioresorbable everolimus-eluting vascular scaffolds (BVS), these temporal changes have not yet been fully investigated. Shin's method may be offer a more suitable technique for this analysis because it includes all the contents of both the lumen and vessel wall. The purpose of this study was to assess the serial changes of necrotic core and dense calcium content in coronary lesions that were treated with a BVS implant using Virtual Histology intravascular ultrasound (VH-IVUS) analyzed using Shin's method. A total of 29 patients (92 coronary segments) were imaged to evaluate the serial changes in necrotic core and dense calcium using Shin's method. Lesions treated with a BVS implant were analyzed with serial VH-IVUS assessments, i.e., pre- and post-stenting, and at 6 months and 2 years follow-up. In Shin's method contours are drawn around the IVUS catheter (instead of delineating the lumen) and the vessel. The mean necrotic core area decreased by 6.9% from post-stenting to 6 months (1.71 ± 1.03 mm2vs. 1.36 ± 0.91 mm2, P = 0.027), and by 20.5% (1.71 ± 1.03 mm2vs. 1.20 ± 0.70 mm2, P = 0.003) from post-steting to 2 years; while the mean dense calcium areas decreased by 27.2% (1.07 ± 0.55 mm2vs. 0.78 ± 0.64 mm2, P = 0.039) from post-stenting and 2 years. At 2 years, absolute necrotic core and dense calcium content were significantly decreased as compared to post-stenting values. The present study demonstrates that the bioresorption process in patients who undergoing BVS device implantation can be assessed using VH-IVUS analysed using Shin's method.

First-in-man clinical use of combined near-infrared spectroscopy and intravascular ultrasound: A potential key to predict distal embolization and no-reflow? (Article)

2010-07-20T00:00:00Z

Multi-modality intra-coronary plaque characterization: A pilot study (Article)

2010-01-07T00:00:00Z

Background: The risk of rupture and subsequent thrombosis of the atherosclerotic coronary plaques is related to the presence of necrotic core with high lipid content. We conducted an exploratory pilot trial to compare the capability for lipid tissue detection using four intra-coronary diagnostic techniques: greyscale intravascular ultrasound (GS IVUS), IVUS radiofrequency data (IVUS RFD) analysis, optical coherence tomography (OCT) and intravascular magnetic resonance spectroscopy (IVMR). Methods: Twenty-four matched target plaques were analyzed with the 4 techniques in non-culprit lesions in five patients with stable angina. Following IVUS pullback, OCT and IVMR was performed. Plaque composition was assessed using established criteria of each technology. Results: Atherosclerotic plaques classified as soft by GS IVUS were mainly composed by fibro-fatty (80%) or necrotic core (20%) by IVUS RFD. These soft plaques were classified as "lipid-rich" by OCT in the majority of cases (80%). IVMR confirmed the presence of lipid with a lipid fraction index ranging between 36 and 79 in these soft plaques. Besides this good agreement for soft plaques, GS IVUS, IVUS RFD and OCT had 100% agreement in the identification of calcified plaques. Conclusion: The present study explored multi-modality imaging of atherosclerotic plaque in-vivo. Assessing specifically lipid-rich plaques, there was generally good agreement for plaque components identified as soft by traditional GS IVUS with RFD and OCT whereas IVMR showed a varying amount of lipid in these regions. Nevertheless there continues to remain inherent variation, namely as a result of the different imaging resolutions and the lack of common nomenclature and classification.

Optical coherence tomography assessment of the acute effects of stent implantation on the vessel wall: A systematic quantitative approach (Article)

2009-12-01T00:00:00Z

Objective: To observe and characterise vessel injury after stenting using optical coherence tomography (OCT), to propose a systematic OCT classification for periprocedural vessel trauma, to evaluate its frequency in stable versus unstable patients and to assess its clinical impact during the hospitalisation period. Setting: Stenting causes vessel injury. Design and interventions: All consecutive patients in whom OCT was performed after stent implantation were included in the study. Qualitative and quantitative assessment of tissue prolapse, intra-stent dissection and edge dissection were performed. Results: Seventy-three patients (80 vessels) were analysed. Tissue prolapse within the stented segment was visible in 78/80 vessels (97.5%). Median number of tissue prolapse sites was 8 (IQR 4-19), mean (SD) area 1.04 (0.9) mm2. Intra-stent dissection flaps were visible in 69/80 vessels (86.3%) (median number 3 (IQR 1.25-6), maximum flap length 450 (220) μm). Fifty-five out of 80 vessels (68.8%) showed dissection cavities (median number 2 (IQR 0-4.75), maximum depth 340 (170) μm). Edge dissection was visible in 20 vessels (mean (SD) length flap 744 (439) μm). The frequency of tissue prolapse or intra-stent dissection was similar in stable and unstable patients (95.6% vs 100%, p = 0.5 for tissue prolapse; 91.1% vs 82.9%, p = 0.3 for intra-stent dissection). There were no events during the hospitalisation period. Conclusions: OCT allows a detailed visualisation of vessel injury after stent implantation and enables a systematic classification and quantification in vivo. In this study, frequency of tissue prolapse or intra-stent dissections after stenting was high, irrespective of the clinical presentation of the patients, and was not associated with clinical events during hospitalisation.

Parameters for coronary plaque vulnerability assessed with multidetector computed tomography and intracoronary ultrasound correlation (Article)

2009-11-01T00:00:00Z

In the absence of a fixed relationship between plaque vulnerability and flow-limiting stenosis, alternative morphological expressions exist that could predict the liability of coronary lesions to rapidly progress or rupture, causing acute coronary syndromes. Modern multidetector computed tomography technology is capable of noninvasively detecting lesion location, attenuation, remodeling and calcification pattern, which may be considered as surrogate morphological markers of vulnerability and could contribute to increase the prognostic value of individual coronary plaque burden.

Incomplete Stent Apposition and Delayed Tissue Coverage Are More Frequent in Drug-Eluting Stents Implanted During Primary Percutaneous Coronary Intervention for ST-Segment Elevation Myocardial Infarction Than in Drug-Eluting Stents Implanted for Stable/Unstable Angina. Insights From Optical Coherence Tomography (Article)

2009-05-01T00:00:00Z

Objectives: The aim of this study was to compare the frequency of incomplete stent apposition (ISA) and struts not covered by tissue at long-term follow-up (as assessed by optical coherence tomography [OCT]) in drug-eluting stents (DES) implanted during primary percutaneous coronary intervention (PCI) for ST-segment elevation myocardial infarction (STEMI) versus DES implanted for unstable and stable angina. Background: Incomplete stent apposition and the absence of strut endothelialization might be linked to stent thrombosis. DES implanted for STEMI might have a higher risk of thrombosis. Methods: Consecutive patients in whom OCT was performed at least 6 months after DES implantation were included in the study. Stent struts were classified on the basis of the presence or absence of ISA and tissue coverage. Results: Forty-seven lesions in 43 patients (1,356 frames, 10,140 struts) were analyzed (49% stable angina, 17% unstable angina, 34% STEMI). Median follow-up time was 9 (range 7 to 72) months. Drug-eluting stents implanted during primary PCI presented ISA more often than DES implanted in stable/unstable angina patients (75% vs. 25.8%, p = 0.001). The frequency of uncovered struts was also higher in the STEMI group (93.8% vs. 67.7%, p = 0.048). On multivariate analysis, DES implantation in STEMI was the only independent predictor of ISA (odds ratio: 9.8, 95% confidence interval: 2.4 to 40.4, p = 0.002) and the presence of uncovered struts at follow-up (odds ratio: 9.5, 95% confidence interval: 1.0 to 90.3, p = 0.049). Conclusions: DES implanted for STEMI had a higher frequency of incompletely apposed struts and uncovered struts as assessed by OCT at follow-up. DES implantation during primary PCI in STEMI was an independent predictor of ISA and the presence of uncovered struts at follow-up.

First case of stenting of a vulnerable plaque in the SECRITT I trial-the dawn of a new era? (Article)

2009-05-01T00:00:00Z

BACKGROUND: A 63-year-old man presented with class II anginal symptoms. INVESTIGATIONS: Cardiac catheterization, intravascular ultrasound (IVUS) virtual histology, optical coherence tomography and off-line palpography. DIAGNOSIS: The patient was diagnosed as having a culprit lesion in the left circumflex artery and a vulnerable plaque in the left anterior descending artery. MANAGEMENT: The culprit lesion was treated with two overlapping drug-eluting stents. The vulnerable plaque was then treated with a self-expanding stent tailored to shield vulnerable plaques (vProtect Luminal Shield). After dilatation of the stent with a low-pressure balloon, IVUS and optical coherence tomography showed excellent apposition of the stent to the vessel wall, with no signs of tissue prolapse or edge dissections. At the 6-month follow-up appointment, the stent showed complete tissue coverage without signs of in-stent restenosis. CONCLUSIONS: Six months of follow-up has demonstrated that a patient with an IVUS-derived, thin capped fibroatheroma was successfully treated with a stent tailored to shield vulnerable plaques.

In vivo validation of CAAS QCA-3D coronary reconstruction using fusion of angiography and intravascular ultrasound (ANGUS) (Article)

2009-04-01T00:00:00Z

Objectives: The CAAS QCA-3D system (Pie Medical Imaging BV, the Netherlands) was validated against 3D reconstructions based on fusion of angiography and intravascular ultrasound (ANGUS), allowing slice by slice validation of the lumen areas and 3D geometric values. Background: Accurate online 3D reconstruction of human coronary arteries is of outmost importance during clinical practice in the catheterization laboratory. The CAAS QCA-3D system provides technology to 3D reconstruct human coronary arteries based on two or more angiographic images, but was not validated in realistic arteries before. Methods: Ten patients were imaged using biplane angiography and an ECG gated (TomTec) intravascular ultrasound (IVUS) pullback (stepsize 0.5 mm, Boston Scientific). The coronary arteries were 3D reconstructed based on (a) fusion of biplane angiography and IVUS (ANGUS) and (b) CAAS QCA-3D using the biplane angiography images. For both systems the length, the curvature and the lumen areas at 0.5 mm spacing were calculated and compared. Results: Bland-Altman analysis indicated that the CAAS QCA-3D system underestimated the lumen areas systematically by 0.45 ± 1.49 mm2. The segment length was slightly underestimated by the CAAS QCA-3D system (62.1 ± 11.3 vs. 63.2 ± 11.4 mm; P < 0.05), while the curvature of the analyzed segments were not statistically different. Conclusions: The CAAS QCA-3D system allows 3D reconstruction of human coronary arteries based on biplane angiography. Validation against the ANGUS system showed that both the 3D geometry and lumen areas are highly correlated which makes the CAAS QCA-3D system a promising tool for applications in the catheterization laboratory and opens possibilities for computational fluid dynamics.

In Vivo Assessment of High-Risk Coronary Plaques at Bifurcations With Combined Intravascular Ultrasound and Optical Coherence Tomography (Article)

2009-04-01T00:00:00Z

Objectives: This study sought to evaluate the in vivo frequency and distribution of high-risk plaques (i.e., necrotic core rich) at bifurcations using a combined plaque assessment with intravascular ultrasound-virtual histology (IVUS-VH) and optical coherence tomography (OCT). Background: Pathological examinations have shown that atherosclerotic plaque rich in necrotic core is prone to develop at bifurcations. High-risk plaque detection could be improved by the combined use of a technique able to detect necrotic core (IVUS-VH) and a high-resolution technique that allows the measurement of the fibrous cap thickness (OCT). Methods: From 30 patients imaged with IVUS-VH and OCT, 103 bifurcations were selected. The main branch was analyzed at the proximal rim of the ostium of the side branch, at the in-bifurcation segment and at the distal rim of the ostium of the side branch. Plaques with more than 10% confluent necrotic core by IVUS-VH were selected and classified as fibroatheroma (FA) or thin-cap fibroatheroma (TCFA) depending on the thickness of the fibrous cap by OCT (>65 or ≤65 μm for FA and TCFA, respectively). Results: Twenty-seven FA (26.2%) and 18 TCFA (17.4%) were found out of the 103 lesions studied. Overall the percentage of necrotic core decreases from proximal to distal rim (16.8% vs. 13.5% respectively, p = 0.01), whereas the cap thickness showed an inverse tendency (130 ± 105 μm vs. 151 ± 68 μm for proximal and distal rim, respectively, p = 0.05). The thin caps were more often located in the proximal rim (15 of 34, 44.1%), followed by the in-bifurcation segment (14 of 34, 41.2%), and were less frequent in the distal rim (5 of 34, 14.7%). Conclusions: The proximal rim of the ostium of the side branch has been identified as a region more likely to contain thin fibrous cap and a greater proportion of necrotic core.

Integration of Multislice Computed Tomography With Magnetic Navigation Facilitates Percutaneous Coronary Interventions Without Additional Contrast Agents (Article)

2009-03-03T00:00:00Z

Objectives: We hypothesized that percutaneous coronary intervention (PCI) without additional contrast agents can be performed by directly integrating multislice computed tomography coronary angiography (CTCA) within the magnetic navigation system (MNS). Background: Increasingly, CTCA is being used in the diagnostic work-up of patients with coronary disease. Its inherent 3-dimensional information should be exploited, as it potentially offers advantages over 2-dimensional radiography in guiding invasive diagnostic and therapeutic interventions. Methods: CTCA-derived centerlines from 15 patients were coregistered and overlaid on real-time fluoroscopic images employing the MNS. Vessels were manually wired with a magnetically enabled guidewire assisted by variable local magnetic fields. Fractional flow reserve (FFR) determined the lesion severity, and the dimensions were quantified by intravascular ultrasound (IVUS). Locations of the IVUS catheter probe along the lesion were incorporated in software to facilitate stenting without contrast agents. Results: The average crossing and fluoroscopic times were 105.3 ± 35.5 s and 83.4 ± 38.6 s, respectively, with no contrast agents used in 11 of 15 patients (73.3%). Contrast agents were used in only 1 of 10 patients (10%) in whom an IVUS was performed. In 4 patients, apart from a "blinded" safety check angiogram, the entire PCI (lesion crossing, stent sizing, positioning, and deployment) was performed without additional contrast agents following the coregistration of the IVUS probe position in the MNS. Conclusions: The integration of pre-procedural CTCA within the MNS can facilitate PCI without additional contrast agents.

Late Stent Recoil of the Bioabsorbable Everolimus-Eluting Coronary Stent and its Relationship With Plaque Morphology (Article)

2008-11-11T00:00:00Z

Objectives: This study sought to evaluate late recoil of a novel bioabsorbable everolimus-eluting coronary stent (BVS), which is composed of a poly-L-lactic acid backbone, coated with a bioabsorbable polymer containing everolimus. Background: Little is known about the mechanical behavior of bioabsorbable polymer stents after deployment in diseased human coronary arteries. Methods: The study population consisted of 16 patients, who were treated with elective BVS implantation for single de novo native coronary artery lesions and were followed at 6 months. All patients underwent an intravascular ultrasound examination at post-procedure and follow-up. A total of 484 paired cross-sectional areas (CSAs) were acquired and analyzed. Late absolute stent recoil was defined as stent area at post-procedure (X) - stent area at follow-up (Y). Late percent stent recoil was defined as (X - Y)/X × 100. In each CSA, plaque morphology was assessed qualitatively and classified as calcific, fibronecrotic, or fibrocellular plaque. Results: Late absolute and percent recoil of the BVS was 0.65 ± 1.71 mm2(95% confidence interval [CI]: 0.49 to 0.80 mm2) and 7.60 ± 23.3% (95% CI: 5.52% to 9.68%). Calcified plaques resulted in significantly less late recoil (0.20 ± 1.54 mm2and 1.97 ± 22.2%) than fibronecrotic plaques (1.03 ± 2.12 mm2and 12.4 ± 28.0%, p = 0.001 and p = 0.001, respectively) or fibrocellular plaque (0.74 ± 1.48 mm2and 8.90 ± 19.8%, p = 0.001 and p = 0.001, respectively). Conclusions: The BVS shrank in size during the follow-up period. The lesion morphology of stented segments might affect the degree of late recoil of the BVS. (ABSORB Everolimus Eluting Coronary Stent System First in Man Clinical Investigation; NCT00300131).

Coronary plaque composition as assessed by greyscale intravascular ultrasound and radiofrequency spectral data analysis (Article)

2008-06-12T00:00:00Z

Objectives: (i) To explore the relation between greyscale intravascular ultrasound (IVUS) plaque qualitative classification and IVUS radiofrequency data (RFD) analysis tissue types; (ii) to evaluate if plaque composition as assessed by RFD analysis can be predicted by visual assessment of greyscale IVUS images. Methods: In 120 IVUS-RFD cross-sections, a sector of the plaque with homogenous tissue composition (e.g., fibrous, fibrofatty, necrotic core, and dense calcium) was selected. Two experienced observers analyzed twice the corresponding greyscale IVUS images to: (1) classify the selected sectors according to greyscale IVUS plaque type classification and (2) predict the tissue type expected in the sector by RFD analysis. Results: In the greyscale IVUS plaque type classification, the observers agreed in 90/120 sectors (κ = 0.64). Calcified, soft and mixed plaques by greyscale IVUS classification were mainly composed of dense calcium, fibrofatty, and necrotic core, respectively, in the RFD analysis. The plaques classified in greyscale IVUS as fibrous were actually fibrous tissue by IVUS RFD in only 30% of the cases. Overall, high interobserver variability in the prediction of RFD results by visual assessment of greyscale IVUS images (κ = 0.23 for observer 1 and 0.55 for observer 2) was found. Sensitivities for detection of calcified tissue and NC by greyscale IVUS visual assessment were 88% and 58%, respectively. Conclusions: High interobserver variability in the prediction of tissue type by visual assessment of greyscale IVUS images was observed. This underlines the need of quantitative methods for the analysis of the ultrasound characteristics of coronary plaque components.

Quantification of coronary plaque by 64-slice computed tomography: A comparison with quantitative intracoronary ultrasound (Article)

2008-05-01T00:00:00Z

BACKGROUND: Noninvasive assessment of coronary atherosclerotic plaque may be useful for risk stratification and treatment of atherosclerosis. MATERIALS AND METHODS: We studied 47 patients to investigate the accuracy of coronary plaque volume measurement acquired with 64-slice multislice computed tomography (MSCT), using newly developed quantification software, when compared with quantitative intracoronary ultrasound (QCU). Quantitative MSCT coronary angiography (QMSCT-CA) was performed to determine plaque volume for a matched region of interest (regional plaque burden) and in significant plaque defined as a plaque with ≥50% area obstruction in QCU, and compared with QCU. Dataset with image blurring and heavy calcification were excluded from analysis. RESULTS: In 100 comparable regions of interest, regional plaque burden was highly correlated (coefficient r = 0.96; P < 0.001) between QCU and QMSCT-CA, but QMSCT-CA overestimated the plaque burden by a mean difference of 7 ± 33 mm (P = 0.03). In 76 significant plaques detected within the regions of interest, plaque volume determined by QMSCT-CA was highly correlated (r = 0.98; P < 0.001) with a slight underestimation of 2 ± 17 mm (P = not significant) when compared with QCU. Calcified and mixed plaque volume was slightly overestimated by 4 ± 19 mm (P = ns) and noncalcified plaque volume was significantly underestimated by 9 ± 11 mm (P < 0.001) with QMSCT-CA. Overall, the limits of agreement for plaque burden/volume measurement between QCU and QMSCT-CA were relatively large. Reproducibility for the measurements of regional plaque burden with QMSCT-CA was good, with a mean intraobserver and interobserver variability of 0% ± 16% and 4% ± 24%, respectively. CONCLUSIONS: Quantification of coronary plaque within selected proximal or middle coronary segments without image blurring and heavy calcification with 64-slice CT was moderately accurate with respect to intravascular ultrasound and demonstrated good reproducibility. Further improvement in CT resolution is required for more reliable measurement of coronary plaques using quantification software.

Three-dimensional and quantitative analysis of atherosclerotic plaque composition by automated differential echogenicity (Article)

2007-12-01T00:00:00Z

Objective: To validate automated and quantitative three-dimensional analysis of coronary plaque composition using intracoronary ultrasound (ICUS). Background: ICUS displays different tissue components based on their acoustic properties in 256 grey-levels. We hypothesised that computer-assisted image analysis (differential echogenicity) would permit automated quantification of several tissue components in atherosclerotic plaques. Methods and Results: Ten 40-mm-long left anterior descending specimens were excised during autopsy of which eight could be successfully imaged by ICUS. Histological sections were taken at 5 mm intervals and analyzed. Since most of the plaques were calcified and having a homogeneous appearance, one specimen with a more heterogeneous composition was further examined: at each interval of 5 mm, 15 additional sections (every 100 μm) were evaluated. Plaques were scored for echogenicity against the adventitia: brighter (hyperechogenic) or less bright (hypoechogenic). Areas of hypoechogenicity correlated with the presence of smooth muscle cells. Areas of hyperechogenicity correlated with presence of collagen, and areas of hyperechogenicity with acoustic shadowing correlated with calcium. None of these comparisons showed statistical significant differences. Conclusion: This ex vivo feasibility study shows that automated three-dimensional differential echogenicity analysis of ICUS images allows identification of different tissue types within atherosclerotic plaques. This technology may play a role as an additional tool in longitudinal studies to trace possible changes in plaque composition.

Effect of perindopril on coronary remodelling: Insights from a multicentre, randomized study (Article)

2007-10-01T00:00:00Z

Aims: This study sought to evaluate the effect of perindopril in coronary remodelling. Methods and results: In this sub-study of a double-blind, multicentre trial, patients without clinical evidence of heart failure were randomized to perindopril 8 mg/day or placebo for at least 3 years and IVUS investigation was performed at both time-points. Positive and negative remodelling were defined as a relative increase (positive remodelling) or decrease (negative remodelling) of the mean vessel cross-sectional area (CSA) > 2 SD of the mean intra-observer difference. A total of 118 matched evaluable IVUS (711 matched 5 mm segments) were available at follow-up. After a median follow-up of 3.0 (inter-quartile range 1.9, 4.1) years, there was no significant difference in the change of plaque CSA between perindopril (360 segments) and placebo (351 segments) groups, P = 0.27. Conversely, the change in vessel CSA was significantly different between groups (perindopril -0.18 ± 2.4 mm2vs. placebo 0.19 ± 2.4, P = 0.04). Negative remodelling occurred more frequently in the perindopril than in the placebo group (34 vs. 25%, P = 0.01). In addition, the placebo group showed a larger, although not significant, mean remodelling index (RI) than the perindopril group (1.03 ± 0.2 vs. 1.00 ± 0.2, P = 0.06). The temporal change in vessel dimensions assessed by the RI was significantly correlated with the change in plaque dimensions (r = 0.48, P < 0.0001). Conclusion: In this sub-analysis of a multicentre, controlled study, long-term administration of perindopril was associated with a constrictive remodelling pattern without affecting the lumen.

Follow-up of internal mammary artery stent with 64-slice CT (Article)

2007-08-01T00:00:00Z

We present a case of 81-year-old woman complaining chest pain after minimal efforts who underwent multiple coronary artery bypass grafts (CABGs) during the last 15 years. A significant in-stent re-stenosis was found at ostium of left internal mammary artery (LIMA). A non-invasive CT coronary angiography (CT-CA) was performed after 6-month follow-up. CT-CA is a reliable non-invasive technique for the follow-up of stents in coronary artery bypass grafts.

Long-Term Effect of Perindopril on Coronary Atherosclerosis Progression (from the PERindopril's Prospective Effect on Coronary aTherosclerosis by Angiography and IntraVascular Ultrasound Evaluation [PERSPECTIVE] Study) (Article)

2007-07-15T00:00:00Z

The multicenter EUROPA trial of 12,218 patients showed that perindopril decreased adverse clinical events in patients with established coronary heart disease. The PERSPECTIVE study, a substudy of the EUROPA trial, evaluated the effect of perindopril on coronary plaque progression as assessed by quantitative coronary angiography and intravascular ultrasound (IVUS). In total 244 patients (mean age 57 years, 81% men) were included. Evaluable paired quantitative coronary angiograms were obtained from 96 patients randomized to perindopril and from 98 patients to placebo. Concomitant treatment at baseline consisted of aspirin (90%), lipid-lowering agents (70%), and β blockers (60%). The primary and secondary end point was the difference of minimum and mean lumen diameters (quantitative coronary angiography) or mean plaque cross-sectional area (IVUS) measured at baseline and 3-year follow-up between the perindopril and placebo groups. After a median follow-up of 3.0 years (range 1.9 to 4.1), no differences in change in quantitative coronary angiographic or IVUS measurements were detected between the perindopril and placebo groups (minimum and mean luminal diameters -0.07 ± 0.4 vs -0.02 ± 0.4 mm, p = 0.34; mean luminal diameter -0.05 ± 0.2 vs -0.05 ± 0.3 mm, p = 0.89; mean plaque cross-sectional area -0.18 ± 1.2 vs -0.02 ± 1.2 mm2, p = 0.48). In conclusion, we found no progression in coronary artery disease by quantitative coronary angiography and IVUS with long-term administration of perindopril or placebo, possibly because most patients were on concomitant treatment with a statin.

Plaque sealing: Are the benefits outweighing the risks? (Article)

2007-02-07T00:00:00Z

A 36-year-old man was admitted with reported short attacks of acute chest pain with small increment of troponin and CK-MB and normal ECG. The 64-slice CT coronary angiography revealed a large non-obstructing non-calcified plaque in the proximal left anterior descending artery with positive vessel remodeling. The conventional coronary angiogram was normal but the intravascular ultrasound confirmed the CT findings. A drug eluting stent was implanted to seal the plaque. During the procedure, myocardial damage had occurred. At 6-month follow-up, 64-slice CT revealed minimal in-stent hyperplasia, which was confirmed at conventional angiography.

Incomplete stent apposition after implantation of paclitaxel-eluting stents or bare metal stents: insights from the randomized TAXUS II trial. (Article)

2005-02-22T00:00:00Z

BACKGROUND: The clinical impact of late incomplete stent apposition (ISA) for drug-eluting stents is unknown. We sought to prospectively investigate the incidence and extent of ISA after the procedure and at 6-month follow-up of paclitaxel-eluting stents in comparison with bare metal stents (BMS) and survey the clinical significance of ISA over a period of 12 months. METHODS AND RESULTS: TAXUS II was a randomized, double-blind study with 536 patients in 2 consecutive cohorts comparing slow-release (SR; 131 patients) and moderate-release (MR; 135 patients) paclitaxel-eluting stents with BMS (270 patients). This intravascular ultrasound (IVUS) substudy included patients who underwent serial IVUS examination after the procedure and at 6 months (BMS, 240 patients; SR, 113; MR, 116). The qualitative and quantitative analyses of ISA were performed by an independent, blinded core laboratory. More than half of the instances of ISA observed after the procedure resolved at 6 months in all groups. No difference in the incidence of late-acquired ISA was observed among the 3 groups (BMS, 5.4%; SR, 8.0%; MR, 9.5%; P=0.306), with a similar ISA volume (BMS, 11.4 mm3; SR, 21.7 mm3; MR, 8.5 mm3; P=0.18). Late-acquired ISA was the result of an increase of vessel area without change in plaque behind the stent. Predictive factors of late-acquired ISA were lesion length, unstable angina, and absence of diabetes. No stent thrombosis occurred in the patients diagnosed with ISA over a period of 12 months. CONCLUSIONS: The incidence and extent of late-acquired ISA are comparable in paclitaxel-eluting stents and BMS. ISA is a pure IVUS finding without clinical repercussions.

Long-term follow-up of incomplete stent apposition in patients who received sirolimus-eluting stent for de novo coronary lesions: an intravascular ultrasound analysis. (Article)

2003-12-02T00:00:00Z

BACKGROUND: Incomplete stent apposition (ISA) has been previously documented after sirolimus-eluting stent (SES) implantation. The aim of this study was to investigate the long-term intravascular ultrasound (IVUS) findings of ISA in patients who received SES. METHODS AND RESULTS: A total of 13 patients who received SES and showed ISA at follow-up IVUS (follow-up I) were investigated. IVUS was performed on all of these patients 12 months later (follow-up II). Quantitative ISA area measurement was also performed at follow-up I and II. No vascular remodeling was observed in the vessel segment with ISA; external elastic membrane area was 19.4+/-6.6 versus 19.5+/-6.4 mm2 at follow-up I and II, respectively. There was also no significant change in external elastic membrane area between vessel segment with ISA and without ISA (+1.5% versus -3.0%, respectively; P=0.27) at late follow-up. The ISA area, either including (2.5+/-1.7 versus 3.8+/-6.3 mm2; P=NS) or excluding (2.5+/-1.8 versus 2.4+/-1.7 mm2; P=NS) a single patient with aneurysm formation, was not significantly different between follow-up I and II. One patient manifested a coronary aneurysm in the stented segment at late follow-up that was probably present at the initial follow-up but masked by thrombus. It was successfully treated with a covered stent. All patients were asymptomatic, and no patient experienced late thrombotic occlusion. CONCLUSIONS: Vessel dimensions and area of ISA did not change over time, except for 1 coronary aneurysm that became apparent. ISA after implantation of a SES was not associated with adverse events at late follow-up.

Usefulness of shear stress pattern in predicting neointima distribution in sirolimus-eluting stents in coronary arteries. (Article)

2003-12-01T00:00:00Z

The true 3-dimensional neointimal thickness distribution in sirolimus-eluting stents was investigated in relation to the shear stress distribution, which was obtained from computational fluid dynamics calculations. Small pits were observed between the stent struts in all patients, and a significant inverse relation between neointimal thickness and shear stress was found, indicating that deeper pits were present in the outside curve of the stented segments.

Coronary restenosis after sirolimus-eluting stent implantation: morphological description and mechanistic analysis from a consecutive series of cases. (Article)

2003-07-22T00:00:00Z

BACKGROUND: We describe the clinical and morphological patterns of restenosis after sirolimus-eluting stent (SES) implantation. METHODS AND RESULTS: From 121 patients with coronary angiography obtained >30 days after SES implantation, restenosis (diameter stenosis >50%) was identified in 19 patients and 20 lesions (located at the proximal 5-mm segment in 30% or within the stent in 70%). Residual dissection after the procedure or balloon trauma outside the stent was identified in 83% of the proximal edge lesions. Lesions within the stent were focal, and stent discontinuity was identified in some lesions evaluated by intravascular ultrasound. CONCLUSIONS: Sirolimus-eluting stent edge restenosis is frequently associated with local trauma outside the stent. In-stent restenosis occurs as a localized lesion, commonly associated with a discontinuity in stent coverage. Local conditions instead of intrinsic drug-resistance to sirolimus are likely to play a major role in post-SES restenosis.

TAXUS III Trial: In-Stent Restenosis Treated With Stent-Based Delivery of Paclitaxel Incorporated in a Slow-Release Polymer Formulation (Article)

2003-02-04T00:00:00Z

BACKGROUND: The first clinical study of paclitaxel-eluting stent for de novo lesions showed promising results. We performed the TAXUS III trial to evaluate the feasibility and safety of paclitaxel-eluting stent for the treatment of in-stent restenosis (ISR). METHODS AND RESULTS: The TAXUS III trial was a single-arm, 2-center study that enrolled 28 patients with ISR meeting the criteria of lesion length < or =30 mm, 50% to 99% diameter stenosis, and vessel diameter 3.0 to 3.5 mm. They were treated with one or more TAXUS NIRx paclitaxel-eluting stents. Twenty-five patients completed the angiographic follow-up at 6 months, and 17 of these underwent intravascular ultrasound (IVUS) examination. No subacute stent thrombosis occurred up to 12 months, but there was one late chronic total occlusion, and additional 3 patients showed angiographic restenosis. The mean late loss was 0.54 mm, with neointimal hyperplasia volume of 20.3 mm3. The major adverse cardiac event rate was 29% (8 patients; 1 non-Q-wave myocardial infarction, 1 coronary artery bypass grafting, and 6 target lesion revascularization [TLR]). Of the patients with TLR, 1 had restenosis in a bare stent implanted for edge dissection and 2 had restenosis in a gap between 2 paclitaxel-eluting stents. Two patients without angiographic restenosis underwent TLR as a result of the IVUS assessment at follow-up (1 incomplete apposition and 1 insufficient expansion of the stent). CONCLUSIONS: Paclitaxel-eluting stent implantation is considered safe and potentially efficacious in the treatment of ISR. IVUS guidance to ensure good stent deployment with complete coverage of target lesion may reduce reintervention.

Sirolimus-eluting stent for treatment of complex in-stent restenosis: the first clinical experience. (Article)

2003-01-15T00:00:00Z

The treatment of ISR remains a therapeutic challenge, since many pharmacological and mechanical approaches have shown disappointing results. The SESs have been reported to be effective in de-novo coronary lesions.

Dynamic Three-Dimensional Echocardiography Offers Advantages for Specific Site Pacing (Article)

2003-01-01T00:00:00Z

We have developed a novel technique for specific site pacing.

Intravascular Ultrasound Findings in the Multicenter, Randomized, Double-Blind RAVEL (RAndomized study with the sirolimus-eluting VElocity balloon-expandable stent in the treatment of patients with de novo native coronary artery Lesions) Trial (Article)

2002-08-13T00:00:00Z

Background— The goal of this intravascular ultrasound investigation was to provide a more detailed morphological analysis of the local biological effects of the implantation of a sirolimus-eluting stent compared with an uncoated stent. Methods and Results— In the RAVEL trial, 238 patients with single de novo lesions were randomized to receive either an 18-mm sirolimus-eluting stent (Bx VELOCITY stent, Cordis) or an uncoated stent (Bx VELOCITY stent). In a subset of 95 patients (sirolimus-eluting stent=48, uncoated stent=47), motorized intravascular ultrasound pullback (0.5 mm/s) was performed at a 6-month follow-up. Stent volumes, total vessel volumes, and plaque-behind-stent volumes were comparable. However, the difference in neointimal hyperplasia (2±5 versus 37±28 mm3) and percent of volume obstruction (1±3% versus 29±20%) at 6 months between the 2 groups was highly significant (P<0.001), emphasizing the nearly complete abolition of the proliferative process inside the drug-eluting stent. Analysis of the proximal and distal edge volumes showed no significant difference between the 2 groups in external elastic membrane or lumen and plaque volume at the proximal and distal edges. There was also no evidence of intrastent thrombosis or persisting dissection at the stent edges. Although there was a higher incidence of incomplete stent apposition in the sirolimus group compared with the uncoated stent group (P<0.05), it was not associated with any adverse clinical events at 1 year. Conclusions— Sirolimus-eluting stents are effective in preventing neointimal hyperplasia without creating edge effect and without affecting the plaque burden behind the struts.

Usefulness of multislice computed tomography for detecting obstructive coronary artery disease. (Article)

2002-04-15T00:00:00Z

The latest generation of multislice spiral computed tomography (MSCT) scanners is capable of noninvasive coronary angiography. We evaluated its diagnostic accuracy to detect stenotic coronary artery disease (CAD). In 53 patients with suspected CAD, contrast-enhanced MSCT and conventional angiography were performed. The CT data were acquired within a single breathhold, and isocardiophasic slices were reconstructed by means of retrospective electrocardiographic gating. Coronary segments of ≥2 mm in diameter, measured by quantitative angiography, were evaluated. In 70% of the 358 available segments, image quality was regarded as adequate for assessment. The overall sensitivity, specificity, and positive and negative predictive values to detect ≥50% stenotic lesions in the assessable segments were 82% (42 of 51 lesions), 93% (285 of 307 nonstenotic segments), and 66% and 97%, respectively, regarding conventional quantitative angiography as the gold standard. Proximal segments were assessable in 92%, and distal segments and side branches in 71% and 50%, respectively. Including the undetected lesions in nonassessable segments, overall sensitivity decreased to 61% but remained 82% for lesions in proximal coronary segments. MSCT correctly predicted absent, single, or multiple lesions in 55% of patients. Thus, despite potentially high image quality, current MSCT protocols offer only reasonable diagnostic accuracy in an unselected patient group with a high prevalence of CAD.

Initial observation regarding changes in vessel dimensions after balloon angioplasty and stenting followed by catheter-based beta-radiation. Is stenting necessary in the setting of catheter-based radiotherapy? (Article)

2002-04-01T00:00:00Z

AIMS: We sought to compare the effect of intracoronary beta-radiation on the vessel dimensions in de novo lesions using three-dimensional intravascular ultrasound quantification after balloon angioplasty and stenting. METHODS AND RESULTS: Forty patients (44 vessels; 28 balloon angioplasty and 16 stenting) treated with catheter-based beta-radiation and 18 non-irradiated control patients (18 vessels; 10 balloon angioplasty and 8 stenting) were investigated by means of three-dimensional volumetric intravascular ultrasound analysis post-procedure and at 6-8 months follow-up. Total vessel (EEM) volume enlarged after both balloon angioplasty and stenting (+37 mm(3) vs +42 mm(3), P=ns), but vessel wall volume (plaque plus media) also increased similarly (+33 mm(3) vs +49 mm(3), P=ns) in the irradiated patients. Lumen volume remained unchanged in both groups (+3 mm(3) vs -7 mm(3), P=ns). In the stent-covered segments, neointima at follow-up was significantly smaller in the irradiated group than the control group (8 mm(3) vs 27 mm(3), P=0.001, respectively), but the total amount of tissue growth was similar in both groups (33 mm(3) vs 29 mm(3), P=ns). CONCLUSIONS: Intracoronary beta-radiation induces vessel enlargement after balloon angioplasty and/or stenting, accommodating tissue growth. Additional stenting may not play an important role in the prevention of constrictive remodelling in the setting of catheter-based intracoronary beta-radiotherapy.

Images in Cardiovascular Medicine. True three-dimensional reconstructed images showing lumen enlargement after sirolimus-eluting stent implantation (Article)

2002-01-01T00:00:00Z

Left Main Rapamycin-Coated Stent (Article)

2002-01-01T00:00:00Z

A 47-year-old man with a history of recurrent coronary interventions underwent percutaneous coronary intervention (PCI) of the left main coronary artery with implantation of a rapamycin-coated stent (BX Velocity 4.0x18 mm). At 6-month follow-up, with no physical complaints, he underwent conventional and multislice spiral computed tomography (MSCT) coronary angiography.

Intravascular ultrasound findings in the multicenter, randomized, double-blind RAVEL (RAndomized study with the sirolimus-eluting VElocity balloon- expandable stent in the treatment of patients with de novo native coronary artery Lesions) trial (Article)

2002-01-01T00:00:00Z

BACKGROUND: The goal of this intravascular ultrasound investigation was to provide a more detailed morphological analysis of the local biological effects of the implantation of a sirolimus-eluting stent compared with an uncoated stent. METHODS AND RESULTS: In the RAVEL trial, 238 patients with single de novo lesions were randomized to receive either an 18-mm sirolimus-eluting stent (Bx VELOCITY stent, Cordis) or an uncoated stent (Bx VELOCITY stent). In a subset of 95 patients (sirolimus-eluting stent=48, uncoated stent=47), motorized intravascular ultrasound pullback (0.5 mm/s) was performed at a 6-month follow-up. Stent volumes, total vessel volumes, and plaque-behind-stent volumes were comparable. However, the difference in neointimal hyperplasia (2+/-5 versus 37+/-28 mm3) and percent of volume obstruction (1+/-3% versus 29+/-20%) at 6 months between the 2 groups was highly significant (P<0.001), emphasizing the nearly complete abolition of the proliferative process inside the drug-eluting stent. Analysis of the proximal and distal edge volumes showed no significant difference between the 2 groups in external elastic membrane or lumen and plaque volume at the proximal and distal edges. There was also no evidence of intrastent thrombosis or persisting dissection at the stent edges. Although there was a higher incidence of incomplete stent apposition in the sirolimus group compared with the uncoated stent group (P<0.05), it was not associated with any adverse clinical events at 1 year. CONCLUSIONS: Sirolimus-eluting stents are effective in preventing neointimal hyperplasia without creating edge effect and without affecting the plaque burden behind the struts.

The pattern of restenosis and vascular remodelling after cold-end radioactive stent implantation. (Article)

2001-08-22T00:00:00Z

Background Edge restenosis is a major problem after radioactive stenting. The cold-end stent has a radioactive mid-segment (15·9mm) and non-radioactive proximal and distal 5·7mm segments. Conceptually this may negate the impact of negative vascular remodelling at the edge of the radiation. Method and Results ECG-gated intravascular ultrasound with three-dimensional reconstruction was performed post-stent implantation and at the 6-month follow-up to assess restenosis within the margins of the stent and at the stent edges in 16 patients. Angiographic restenosis was witnessed in four patients, all in the proximal in-stent position. By intravascular ultrasound in-stent neointimal hyperplasia, with a >50% stented cross-sectional area, was seen in eight patients. This was witnessed proximally (n=2), distally (n=2) and in both segments (n=4). Echolucent tissue, dubbed the ‘black hole’ was seen as a significant component of neointimal hyperplasia in six out of the eight cases of restenosis. Neointimal hyperplasia was inhibited in the area of radiation: Δ neointimal hyperplasia=3·72mm3(8·6%); in-stent at the edges of radiation proximally and distally Δ neointimal hyperplasia was 7·9mm3(19·0%) and 11·4mm3(25·6%), respectively (P=0·017). At the stent edges there was no significant change in lumen volume. Conclusions Cold-end stenting results in increased neointimal hyperplasia in in-stent non-radioactive segments.

Three dimensional intravascular ultrasonic assessment of the local mechanism of restenosis after balloon angioplasty (Article)

2001-01-01T00:00:00Z

OBJECTIVE: To assess the mechanism of restenosis after balloon angioplasty. DESIGN: Prospective study. PATIENTS: 13 patients treated with balloon angioplasty. INTERVENTIONS: 111 coronary subsegments (2 mm each) were analysed after balloon angioplasty and at a six month follow up using three dimensional intravascular ultrasound (IVUS). MAIN OUTCOME MEASURES: Qualitative and quantitative IVUS analysis. Total vessel (external elastic membrane), plaque, and lumen volume were measured in each 2 mm subsegment. Delta values were calculated (follow up - postprocedure). Remodelling was defined as any (positive or negative) change in total vessel volume. RESULTS: Positive remodelling was observed in 52 subsegments while negative remodelling occurred in 44. Remodelling, plaque type, and dissection were heterogeneously distributed along the coronary segments. Plaque composition was not associated with changes in IVUS indices, whereas dissected subsegments had a greater increase in total vessel volume than those without dissection (1.7 mm(3) v -0.33 mm(3), p = 0.04). Change in total vessel volume was correlated with changes in lumen (p < 0.05, r = 0.56) and plaque volumes (p < 0.05, r = 0.64). The site with maximum lumen loss was not the same site as the minimum lumen area at follow up in the majority (n = 10) of the vessels. In the multivariate model, residual plaque burden had an influence on negative remodelling (p = 0.001, 95% confidence interval (CI) -0.391 to -0.108), whereas dissection had an effect on total vessel increase (p = 0.002, 95% CI 1.168 to 4.969). CONCLUSIONS: The mechanism of lumen renarrowing after balloon angioplasty appears to be determined by unfavourable remodelling. However, different patterns of remodelling may occur in individual injured coronary segments, which highlights the complexity and influence of local factors in the restenotic process.

Aneurysm of the abdominal aorta (Article)

2001-01-01T00:00:00Z

Prominent role of tensile stress in propagation of a dissection after coronary stenting: computational fluid dynamic analysis on true 3d-reconstructed segment (Article)

2001-01-01T00:00:00Z

"Edge Effect" of 32P Radioactive Stents Is Caused by the Combination of Chronic Stent Injury and Radioactive Dose Falloff (Article)

2001-01-01T00:00:00Z

BACKGROUND: Radioactive stents have been reported to reduce in-stent neointimal thickening. An unexpected increase in neointimal response was observed, however, at the stent-to-artery transitions, the so-called "edge effect." To investigate the factors involved in this edge effect, we studied stents with 1 radioactive half and 1 regular nonradioactive half, thereby creating a midstent radioactive dose-falloff zone next to a nonradioactive stent-artery transition at one side and a radioactive stent-artery transition at the other side. METHODS AND RESULTS: Half-radioactive stents (n=20) and nonradioactive control stents (n=10) were implanted in the coronary arteries of Yucatan micropigs. Animals received aspirin and clopidogrel as antithrombotics. After 4 weeks, a significant midstent stenosis was observed by angiography in the half-radioactive stents. Two animals died suddenly because of coronary occlusion at this mid zone at 8 and 10 weeks. At 12-week follow-up angiography, intravascular ultrasound and histomorphometry showed a significant neointimal thickening at the midstent dose-falloff zone of the half-radioactive stents, but not at the stent-to-artery transitions at both extremities. Such a midstent response (mean angiographic late loss 1.0 mm) was not observed in the nonradioactive stents (mean loss 0.4 to 0.6 mm; P< 0.01). CONCLUSIONS: The edge effect of high-dose radioactive stents in porcine coronary arteries is associated with the combination of stent injury and radioactive dose falloff.

Relationship between tensile stress and plaque growth after balloon angioplasty treated with and without intracoronary beta-brachytherapy. (Article)

2000-12-01T00:00:00Z

AIMS: We investigated the influence of tensile stress on plaque growth after balloon angioplasty with and without beta-radiation therapy. METHODS AND RESULTS: Thirty-one consecutive patients successfully treated with balloon angioplasty were analysed qualitatively and quantitatively by means of an ECG-gated three-dimensional intravascular ultrasound post-procedure and at follow-up. Eighteen patients were irradiated with catheter-based beta-radiation ((90)Sr/(90)Y source) and 13 were not (control). Studied segments were divided into 2 mm subsegments. Thus 184 irradiated and 111 non-irradiated subsegments were included. Tensile stress was calculated according to Laplace's law. The radiation dose was calculated by means of dose-volume histograms. Plaque growth was positively correlated to tensile stress in both the radiation and control groups (r=0.374, P=0.0001 and r=0.305, P=0.001). Low-dose subsegments (<6 Gy) had a significant correlation (r=0.410, P=0.0001) whereas no correlation was observed in the effective-dose subsegments (> or = 6 Gy). Multivariate analysis identified tensile stress as the only independent predictor of plaque increase in non-irradiated subsegments, whereas actual dose and plaque morphology were stronger predictors in irradiated subsegments. CONCLUSION: The results of this study suggest that plaque growth is related to tensile stress after balloon angioplasty. Intracoronary brachytherapy may alter the biophysical process on plaque growth when the prescribed dose is effectively delivered.

Three-dimensional intravascular ultrasonic volumetric quantification of stent recoil and neointimal formation of two new generation tubular stents (Article)

2000-01-15T00:00:00Z

Currently, several different designs of coronary stents are available. However, only a few of the new generation stents have been investigated in large randomized trials. Mechanical behavior of first-generation stents (Palmaz-Schatz, Gianturco-Roubin) may not be applied to the new designs. We investigated the chronic mechanical behavior (recoil) of 2 stents recently approved by the Food and Drug Administration (MULTILINK and NIR). Forty-eight patients with single-stent implantation (23 MULTILINK and 25 NIR) were assessed by means of volumetric 3-dimensional intravascular ultrasound analysis after the procedure and at 6-month follow-up. In addition, volumetric assessment of neointimal formation was performed. No significant chronic stent recoil was detected in both groups (Δ MULTILINK stent volume: +5.6 ± 41 mm3 [p = NS] and Δ NIR stent volume + 2.1 ± 26 mm3 [p = NS]). A similar degree of neointimal formation at 6 months was observed between the 2 stents (MULTILINK 46 ± 31.9 mm3 vs NIR 39.9 ± 27.6 mm3, p = NS). In conclusion, these 2 second-generation tubular stents did not show chronic recoil and appeared to promote similar proliferative response after implantation in human coronary arteries.

Coronary stent implantation in a septal perforator artery: case report and review of the literature. (Article)

2000-01-01T00:00:00Z

Septal perforator arteries play an important role in the blood supply of the anterior interventricular septum. Their intramyocardial course makes them inaccessible for coronary bypass revascularization. Although modern catheter-based techniques might be superior to coronary bypass grafting in offering the most complete revascularization in selected patient populations, a systematic review of the literature revealed a paucity of data regarding the outcome of these patients. The present report describes coronary stent implantation in a dominant septal perforator artery and the analysis of the anatomic relationship between the stent and the intraventricular septum using a new imaging technique, catheter-based intracardiac ultrasound.

Positive Geometric Vascular Remodeling Is Seen After Catheter-Based Radiation Followed by Conventional Stent Implantation but Not After Radioactive Stent Implantation (Article)

2000-01-01T00:00:00Z

Background—Recent reports demonstrate that intracoronary radiation affects not only neointimal formation but also vascular remodeling. Radioactive stents and catheter-based techniques deliver radiation in different ways, suggesting that different patterns of remodeling after each technique may be expected. Methods and Results—We analyzed remodeling in 18 patients after conventional stent implantation, 16 patients after low-activity radioactive stent implantation, 16 patients after higher activity radioactive stent implantation, and, finally, 17 patients who underwent catheter-based radiation followed by conventional stent implantation. Intravascular ultrasound with 3D reconstruction was used after stent implantation and at the 6-month follow-up to assess remodeling within the stent margins and at its edges. Preprocedural characteristics were similar between groups. In-stent neointimal hyperplasia (NIH) was inhibited by high-activity radioactive stent implantation (NIH 9.0 mm3) and by catheter-based radiation followed by conventional stent implantation (NIH 6.9 mm3) compared with low-activity radioactive stent implantation (NIH 21.2 mm3) and conventional stent implantation (NIH 20.8 mm3) (P=0.008). No difference in plaque or total vessel volume was seen behind the stent in the conventional, low-activity, or high-activity stent implantation groups. However, significant increases in plaque behind the stent (15%) and in total vessel volume (8%) were seen in the group that underwent catheter-based radiation followed by conventional stent implantation. All 4 groups demonstrated significant late lumen loss at the stent edges; however, edge restenosis was seen only in the group subjected to high-activity stent implantation and appeared to be due to an increase in plaque and, to a lesser degree, to negative remodeling. Conclusions—Distinct differences in the patterns of remodeling exist between conventional, radioactive, and catheter-based radiotherapy with stenting.

Residual Plaque Burden, Delivered Dose, and Tissue Composition Predict 6-Month Outcome After Balloon Angioplasty and Beta-Radiation Therapy (Article)

2000-01-01T00:00:00Z

Background—Inhomogeneity of dose distribution and anatomic aspects of the atherosclerotic plaque may influence the outcome of irradiated lesions after balloon angioplasty (BA). We evaluated the influence of delivered dose and morphological characteristics of coronary stenoses treated with ß-radiation after BA. Methods and Results—Eighteen consecutive patients treated according to the Beta Energy Restenosis Trial 1.5 were included in the study. The site of angioplasty was irradiated with the use of a ß-emitting 90Sr/90Y source. With the side branches used as anatomic landmarks, the irradiated area was identified and volumetric assessment was performed by 3D intracoronary ultrasound imaging after treatment and at 6 months. The type of tissue, the presence of dissection, and the vessel volumes were assessed every 2 mm within the irradiated area. The minimal dose absorbed by 90% of the adventitial volume (Dv90Adv) was calculated in each 2-mm segment. Diffuse calcified subsegments and those containing side branches were excluded. Two hundred six coronary subsegments were studied. Of those, 55 were defined as soft, 129 as hard, and 22 as normal/intimal thickening. Plaque volume showed less increase in hard segments as compared with soft and normal/intimal thickening segments (P<0.0001). Dv90Adv was associated with plaque volume at follow-up after a polynomial equation with linear and nonlinear components (r=0.71; P=0.0001). The multivariate regression analysis identified the independent predictors of the plaque volume at follow-up: plaque volume after treatment, Dv90Adv, and type of plaque. Conclusions—Residual plaque burden, delivered dose, and tissue composition play a fundamental role in the volumetric outcome at 6-month follow-up after ß-radiation therapy and BA.

Geographic Miss (Article)

2000-01-01T00:00:00Z

Background—A recognized limitation of endovascular ß-radiation therapy is the development of new stenosis at the edges of the irradiated area. The combination of injury and low-dose radiation may be the precursor of this phenomenon. We translated the radio-oncological concept of "geographic miss" to define cases in which the radiation source did not fully cover the injured area. The aims of the study were to determine the incidence and causes of geographic miss and evaluate the impact of this inadequate treatment on the outcome of patients treated with intracoronary ß-radiation. Methods and Results—We analyzed 50 consecutive patients treated with ß-radiation after percutaneous coronary intervention. The prescribed dose ranged between 12 and 20 Gy at 2 mm from the source axis. By means of quantitative coronary angiography, the irradiated segment (IRS) and both edges were studied before and after intervention and at 6-month follow-up. Edges that were injured during the procedure constituted the geographic miss edges. Twenty-two edges were injured during the intervention, mainly because of procedural complications that extended the treatment beyond the margins of the IRS. Late loss was significantly higher in geographic miss edges than in IRSs and uninjured edges (0.84±0.6 versus 0.15±0.4 and 0.09±0.4 mm, respectively; P<0.0001). Similarly, restenosis rate was significantly higher in the injured edges (10% within IRS, 40.9% in geographic miss edges, and 1.9% in uninjured edges; P<0.001). Conclusions—These data support the hypothesis that the combination of injury and low-dose ß-radiation induces deleterious outcome.

Coronary bifurcation stenting using dedicated bifurcation stents (Article)

2000-01-01T00:00:00Z

We report three cases of successful implantation of three different stents specially designed for bifurcation lesions, guided by intracoronary ultrasound. The BARD and AVE are true bifurcated stents for side-branch access and the NIR-Side Royal is a single modified NIR stent with an aperture to allow provisional bifurcation stenting. These designs introduce a new era in percutaneous management of coronary bifurcation lesions. Cathet. Cardiovasc. Intervent. 49:105–111, 2000.

Diagnosis of an Intracoronary Thrombus With Intravascular Ultrasound (Article)

2000-01-01T00:00:00Z

A60-year-old man was referred for coronary angiography because of exertional angina (Canadian Cardiovascular Society angina classification type II). Twelve years earlier, he had had a myocardial infarction with a venous bypass graft to the right coronary artery.

Geographic miss: a cause of treatment failure in radio-oncology applied to intracoronary radiation therapy (Article)

2000-01-01T00:00:00Z

BACKGROUND: A recognized limitation of endovascular beta-radiation therapy is the development of new stenosis at the edges of the irradiated area. The combination of injury and low-dose radiation may be the precursor of this phenomenon. We translated the radio-oncological concept of "geographic miss" to define cases in which the radiation source did not fully cover the injured area. The aims of the study were to determine the incidence and causes of geographic miss and evaluate the impact of this inadequate treatment on the outcome of patients treated with intracoronary beta-radiation. METHODS AND RESULTS: We analyzed 50 consecutive patients treated with beta-radiation after percutaneous coronary intervention. The prescribed dose ranged between 12 and 20 Gy at 2 mm from the source axis. By means of quantitative coronary angiography, the irradiated segment (IRS) and both edges were studied before and after intervention and at 6-month follow-up. Edges that were injured during the procedure constituted the geographic miss edges. Twenty-two edges were injured during the intervention, mainly because of procedural complications that extended the treatment beyond the margins of the IRS. Late loss was significantly higher in geographic miss edges than in IRSs and uninjured edges (0.84+/-0.6 versus 0.15+/-0.4 and 0.09+/-0.4 mm, respectively; P<0.0001). Similarly, restenosis rate was significantly higher in the injured edges (10% within IRS, 40.9% in geographic miss edges, and 1.9% in uninjured edges; P<0.001). CONCLUSIONS: These data support the hypothesis that the combination of injury and low-dose beta-radiation induces deleterious outcome.

Residual plaque burden, delivered dose, and tissue composition predict 6-month outcome after balloon angioplasty and beta-radiation therapy (Article)

2000-01-01T00:00:00Z

BACKGROUND: Inhomogeneity of dose distribution and anatomic aspects of the atherosclerotic plaque may influence the outcome of irradiated lesions after balloon angioplasty (BA). We evaluated the influence of delivered dose and morphological characteristics of coronary stenoses treated with beta-radiation after BA. METHODS AND RESULTS: Eighteen consecutive patients treated according to the Beta Energy Restenosis Trial 1.5 were included in the study. The site of angioplasty was irradiated with the use of a beta-emitting (90)Sr/(90)Y source. With the side branches used as anatomic landmarks, the irradiated area was identified and volumetric assessment was performed by 3D intracoronary ultrasound imaging after treatment and at 6 months. The type of tissue, the presence of dissection, and the vessel volumes were assessed every 2 mm within the irradiated area. The minimal dose absorbed by 90% of the adventitial volume (D(v90)Adv) was calculated in each 2-mm segment. Diffuse calcified subsegments and those containing side branches were excluded. Two hundred six coronary subsegments were studied. Of those, 55 were defined as soft, 129 as hard, and 22 as normal/intimal thickening. Plaque volume showed less increase in hard segments as compared with soft and normal/intimal thickening segments (P<0.0001). D(v90)Adv was associated with plaque volume at follow-up after a polynomial equation with linear and nonlinear components (r = 0.71; P = 0.0001). The multivariate regression analysis identified the independent predictors of the plaque volume at follow-up: plaque volume after treatment, D(v90)Adv, and type of plaque. CONCLUSIONS: Residual plaque burden, delivered dose, and tiss composition play a fundamental role in the volumetric outcome at 6-month follow-up after beta-radiation therapy and BA.

Positive geometric vascular remodeling is seen after catheter-based radiation followed by conventional stent implantation but not after radioactive stent implantation (Article)

2000-01-01T00:00:00Z

BACKGROUND: Recent reports demonstrate that intracoronary radiation affects not only neointimal formation but also vascular remodeling. Radioactive stents and catheter-based techniques deliver radiation in different ways, suggesting that different patterns of remodeling after each technique may be expected. METHODS AND RESULTS: We analyzed remodeling in 18 patients after conventional stent implantation, 16 patients after low-activity radioactive stent implantation, 16 patients after higher activity radioactive stent implantation, and, finally, 17 patients who underwent catheter-based radiation followed by conventional stent implantation. Intravascular ultrasound with 3D reconstruction was used after stent implantation and at the 6-month follow-up to assess remodeling within the stent margins and at its edges. Preprocedural characteristics were similar between groups. In-stent neointimal hyperplasia (NIH) was inhibited by high-activity radioactive stent implantation (NIH 9.0 mm(3)) and by catheter-based radiation followed by conventional stent implantation (NIH 6.9 mm(3)) compared with low-activity radioactive stent implantation (NIH 21.2 mm(3)) and conventional stent implantation (NIH 20.8 mm(3)) (P:=0.008). No difference in plaque or total vessel volume was seen behind the stent in the conventional, low-activity, or high-activity stent implantation groups. However, significant increases in plaque behind the stent (15%) and in total vessel volume (8%) were seen in the group that underwent catheter-based radiation followed by conventional stent implantation. All 4 groups demonstrated significant late lumen loss at the stent edges; however, edge restenosis was seen only in the group subjected to high-activity stent implantation and appeared to be due to an increase in plaque and, to a lesser degree, to negative remodeling. CONCLUSIONS: Distinct differences in the patterns of remodeling exist between conventional, radioactive, and catheter-based radiotherapy with stenting.

Three-dimensional intravascular ultrasound assessment of noninjured edges of beta-irradiated coronary segments (Article)

2000-01-01T00:00:00Z

BACKGROUND: The "edge effect," late lumen loss at the margins of the treated segment, has become an important issue in the field of coronary brachytherapy. The aim of the present study was to assess the edge effect in noninjured margins adjacent to the irradiated segments after catheter-based intracoronary beta-irradiation. METHODS AND RESULTS: Fifty-three vessels were assessed by means of 3-dimensional intravascular ultrasound after the procedure and at 6- to 8-month follow-up. Fourteen vessels (placebo group) did not receive radiation (sham source), whereas 39 vessels were irradiated. In the irradiated group, 48 edges (5 mm in length) were identified as noninjured, whereas 18 noninjured edges were selected in the placebo group. We compared the volumetric intravascular ultrasound measurements of the noninjured edges of the irradiated vessels with the fully irradiated nonstented segments (IRS, n=27) (26-mm segments received the prescribed 100% isodose) and the noninjured edges of the vessels of the placebo patients. The lumen decreased (6 mm(3)) in the noninjured edges of the irradiated vessels at follow-up (P:=0. 001). We observed a similar increase in plaque volume in all segments: noninjured edges of the irradiated group (19.6%), noninjured edges of the placebo group (21.5%), and IRS (21.0%). The total vessel volume increased in the IRS in the 3 groups. No edge segment was subject to repeat revascularization. CONCLUSIONS: The edge effect occurs in the noninjured margins of radiation source train in both irradiated and placebo patients. Thus, low-dose radiation may not play an important role in this phenomenon, whereas nonmeasurable device injury may be considered a plausible alternative explanation.

Coronary stent implantation in a septal perforator artery: case report and review of the literature (Article)

2000-01-01T00:00:00Z

Comparison of brachytherapy strategies based on dose-volume histograms derived from quantitative intravascular ultrasound. (Article)

1999-04-01T00:00:00Z

PURPOSE: We present in this paper the comparison, by simulation, of different treatment strategies based either on beta- or gamma-sources, both with and without a centering device. Ionizing radiation to prevent restenosis is an emerging modality in interventional cardiology. Numerous clinical studies are presently being performed or planned, but there is variability in dose prescription, and both gamma- and beta-emitters are used, leading to a wide range of possible dose distributions over the arterial vessel wall. This paper discusses the potential merits of dose-volume histograms (DVH) based on three-dimensional (3-D) reconstruction of electrocardiogram (ECG)-gated intravascular ultrasound (IVUS) to compare brachytherapy treatment strategies. MATERIALS AND METHODS: DVH describe the cumulative distribution of dose over three specific volumes: (1) at the level of the luminal surface, a volume was defined with a thickness of 0.1 mm from the automatically detected contour of the highly echogenic blood-vessel interface; (2) at the level of the IVUS echogenic media-adventitia interface (external elastic lamina [EEL]), an adventitial volume was computed considering a 0.5-mm thickness from EEL; and (3) the volume encompassed between the luminal surface and the EEL (plaque + media). The IVUS data used were recorded in 23 of 31 patients during the Beta Energy Restenosis Trial (BERT) conducted in our institution. RESULTS: On average, the minimal dose in 90% of the adventitial volume was 37 +/- 16% of the prescribed dose; the minimal dose in 90% of the plaque + media volume was 58 +/- 24% and of the luminal surface volume was 67 +/- 31%. The minimal dose in the 10% most exposed luminal surface volume was 296 +/- 42%. Simulations of the use of a gamma-emitter and/or a radioactive source train centered in the lumen are reported, with a comparison of the homogeneity of the dose distribution.

Intracoronary ultrasound longitudinal reconstruction of a postangioplasty coronary artery dissection (Article)

1999-01-01T00:00:00Z

Late coronary occlusion after intracoronary brachytherapy (Article)

1999-01-01T00:00:00Z

BACKGROUND: Intracoronary brachytherapy appears to be a promising technology to prevent restenosis. Presently, limited data are available regarding the late safety of this therapeutic modality. The aim of the study was to determine the incidence of late (>1 month) thrombosis after PTCA and radiotherapy. METHODS AND RESULTS: From April 1997 to March 1999, we successfully treated 108 patients with PTCA followed by intracoronary beta-radiation. Ninety-one patients have completed at least 2 months of clinical follow-up. Of these patients, 6.6% (6 patients) presented with sudden thrombotic events confirmed by angiography 2 to 15 months after intervention (2 balloon angioplasty and 4 stent). Some factors (overlapping stents, unhealed dissection) may have triggered the thrombosis process, but the timing of the event is extremely unusual. Therefore, the effect of radiation on delaying the healing process and maintaining a thrombogenic coronary surface is proposed as the most plausible mechanism to explain such late events. CONCLUSIONS: Late and sudden thrombosis after PTCA followed by intracoronary radiotherapy is a new phenomenon in interventional cardiology.

Geometric vascular remodeling after balloon angioplasty and beta-radiation therapy: A three-dimensional intravascular ultrasound study (Article)

1999-01-01T00:00:00Z

BACKGROUND: Endovascular radiation appears to inhibit intimal thickening after overstretching balloon injury in animal models. The effect of brachytherapy on vascular remodeling is unknown. The aim of the study was to determine the evolution of coronary vessel dimensions after intracoronary irradiation after successful balloon angioplasty in humans. METHODS AND RESULTS: Twenty-one consecutive patients treated with balloon angioplasty and beta-radiation according to the Beta Energy Restenosis Trial-1.5 were included in the study. Volumetric assessment of the irradiated segment and both edges was performed after brachytherapy and at 6-month follow-up. Intravascular ultrasound images were acquired by means of ECG-triggered pullback, and 3-D reconstruction was performed by automated edge detection, allowing the calculation of lumen, plaque, and external elastic membrane (EEM) volumes. In the irradiated segments, mean EEM and plaque volumes increased significantly (451+/-128 to 490.9+/-159 mm(3) and 201.2+/-59 to 241.7+/-74 mm(3); P=0.01 and P=0.001, respectively), whereas luminal volume remained unchanged (250.8+/-91 to 249.2+/-102 mm(3); P=NS). The edges demonstrated an increase in mean plaque volume (26.8+/-12 to 32. 6+/-10 mm(3), P=0.0001) and no net change in mean EEM volume (71. 4+/-24 to 70.9+/-24 mm(3), P=NS), resulting in a decrease in mean luminal volume (44.6+/-16 to 38.3+/-16 mm(3), P=0.01). CONCLUSIONS: A different pattern of remodeling is observed in coronary segments treated with beta-radiation after successful balloon angioplasty. In the irradiated segments, the adaptive increase of EEM volume appears to be the major contributor to the luminal volume at follow-up. Conversely, both edges showed an increase in plaque volume without a net change in EEM volume.

Preserved endothelium-dependent vasodilation in coronary segments previously treated with balloon angioplasty and intracoronary irradiation (Article)

1999-01-01T00:00:00Z

BACKGROUND: Abnormal endothelium-dependent coronary vasomotion has been reported after balloon angioplasty (BA), as well as after intracoronary radiation. However, the long-term effect on coronary vasomotion is not known. The aim of this study was to evaluate the long-term vasomotion of coronary segments treated with BA and brachytherapy. METHODS AND RESULTS: Patients with single de novo lesions treated either with BA followed by intracoronary beta-irradiation (according to the Beta Energy Restenosis Trial-1.5) or with BA alone were eligible. Of these groups, those patients in stable condition who returned for 6-month angiographic follow-up formed the study population (n=19, irradiated group and n=11, control group). Endothelium-dependent coronary vasomotion was assessed by selective infusion of serial doses of acetylcholine (ACh) proximally to the treated area. Mean luminal diameter was calculated by quantitative coronary angiography both in the treated area and in distal segments. Endothelial dysfunction was defined as a vasoconstriction after the maximal dose of ACh (10(-6) mol/L). Seventeen irradiated segments (89.5%) demonstrated normal endothelial function. In contrast, 10 distal nonirradiated segments (53%) and 5 control segments (45%) demonstrated endothelium-dependent vasoconstriction (-19+/-17% and -9.0+/-5%, respectively). Mean percentage of change in mean luminal diameter after ACh was significantly higher in irradiated segments (P=0.01). CONCLUSIONS: Endothelium-dependent vasomotion of coronary segments treated with BA followed by beta-radiation is restored in the majority of stable patients at 6-month follow-up. This functional response appeared to be better than those documented both in the distal segments and in segments treated with BA alone.

beta-Particle-emitting radioactive stent implantation. A safety and feasibility study (Article)

1999-01-01T00:00:00Z

BACKGROUND: This study represents the Heart Center Rotterdam's contribution to the Isostents for Restenosis Intervention Study, a nonrandomized multicenter trial evaluating the safety and feasibility of the radioactive Isostent in patients with single coronary artery disease. Restenosis after stent implantation is primarily caused by neointimal hyperplasia. In animal studies, beta-particle-emitting radioactive stents decrease neointimal hyperplasia by inhibiting smooth muscle cell proliferation. METHODS AND RESULTS: The radioisotope (32)P, a beta-particle emitter with a half-life of 14.3 days, was directly embedded into the Isostent. The calculated range of radioactivity was 0.75 to 1.5 microCi. Quantitative coronary angiography measurements were performed before and after the procedure and at 6-month follow-up. A total of 31 radioactive stents were used in 26 patients; 30 (97%) were successfully implanted, and 1 was embolized. Treated lesions were in the left anterior descending coronary artery (n=12), the right coronary artery (n=8), or the left circumflex coronary artery (n=6). Five patients received additional, nonradioactive stents. Treated lesion lengths were 13+/-4 mm, with a reference diameter of 2.93+/-0. 47 mm. Minimum lumen diameter increased from 0.87+/-0.28 mm preprocedure to 2.84+/-0.35 mm postprocedure. No in-hospital adverse cardiac events occurred. All patients received aspirin indefinitely and ticlopidine for 4 weeks. Twenty-three patients (88%) returned for 6-month angiographic follow-up; 17% of them had in-stent restenosis, and 13% had repeat revascularization. No restenosis was observed at the stent edges. Minimum lumen diameter at follow-up averaged 1.85+/-0.69 mm, which resulted in a late loss of 0.99+/-0. 59 mm and a late loss index of 0.53+/-0.35. No other major cardiac events occurred during the 6-month follow-up. CONCLUSIONS: The use of radioactive stents with an activity of 0.75 to 1.5 microCi is safe and feasible.

Usefulness of three-dimensional reconstruction for interpretation and quantitative analysis of intracoronary ultrasound during stent deployment. (Article)

1996-04-01T00:00:00Z

In conclusion, on-line 3-D ICUS is feasible during stent implantation, more sensitive than 2-D ICUS in the assessment of optimal stent expansion, and requires a shorter time for analysis.

Intracoronary Heparin Delivery in Humans (Article)

1995-01-01T00:00:00Z

Background Inefficacy of systemic drug administration for restenosis prevention may partially relate to insufficient local drug concentration. This study aimed to evaluate the acute feasibility and long-term outcome of using an infusion-perfusion coil balloon, Dispatch. Methods and Results In 22 patients after balloon angioplasty, the coil balloon was studied for (1) feasibility of local heparin delivery, (2) symptoms and signs of ischemia during prolonged deployment compared with angioplasty balloon occlusion, (3) coronary pressure and flow distal to the inflated device, and (4) long-term clinical and angiographic results. During prolonged intracoronary deployment of the coil balloon (29±8 minutes), 5 of 22 patients developed mild chest pain versus 20 of 22 during angioplasty (275±283 seconds). Neither hemodynamic nor vectorcardiographic signs of ischemia were detected, in contrast to angioplasty balloon occlusion. Baseline flow across the coil balloon was 44±31 mL/min, increasing by a factor of 1.8±0.7 during pharmacologically induced hyperemia. A mean volume of 14.2±6.1 mL containing 1416±608 IU of heparin was infused locally at a pressure of 122±54 mm Hg. At 7±1-month follow-up, 1 asymptomatic patient had died, and of the remaining 21, 17 (81%) were asymptomatic. Angiographic follow-up was obtained in 15 of 21 patients (71%), including all 4 symptomatic patients. Mean minimal luminal diameter after the procedure was 2.16±0.49 mm and at follow-up, 1.89±0.45 mm, which corresponds to a restenosis rate (diameter stenosis 50%) of 7% (1/15). Conclusions Intracoronary use of the coil balloon after balloon angioplasty proved to be feasible and subjectively as well as objectively well tolerated during prolonged deployment by virtue of its perfusion properties. High volumes of heparin solution can be infused locally at very low pressure. No unfavorable clinical or angiographic long-term effects were observed.