Ozaki, Y.

Coronary CT angiographic characteristics of culprit lesions in acute coronary syndromes not related to plaque rupture as defined by optical coherence tomography and angioscopy (Article)

2011-11-01T00:00:00Z

Aims Pathological and clinical optical coherence tomography (OCT) studies have indicated that acute coronary syndrome (ACS) lesions have either ruptured fibrous caps (RFC-ACS) or intact fibrous caps (IFC-ACS). Although computed tomographic (CT) angiographic characteristics of RFC-ACS include low-attenuation plaques and positive plaque remodelling, features associated with IFC-ACS have not been previously described. The aim of this study was to assess the CT characteristics of IFC-ACS lesions. Methods and resultsSeventy-four patients with ACS/stable angina consented to multimodality imaging, of which 66 underwent CT angiography. Of these, 57 culprit lesions in 57 patients were evaluated with sufficient image quality from all four of OCT, angioscopy, intravascular ultrasound, and CT angiography. Intraluminal thrombus was assessed by OCT/angioscopy, and culprit lesions further classified by OCT-based demonstration of fibrous cap integrity. Of 35 culprit lesions with ACS, OCT revealed IFC with thrombus in 10 (29) and RFC in the remaining 25 (71); all 22 lesions with stable angina had intact fibrous caps. Fibrous caps were significantly thinner in RFC-ACS than IFC-ACS and stable angina (45 ± 12, 131 ± 57, and 321 ± 146 μm, respectively; P 0.001). CT angiography revealed that low-attenuation plaques were more frequently observed in RFC-ACS than IFC-ACS and stable angina (88, 40, and 18; P 0.001) lesions. Similarly, positive remodelling was more predominantly seen in RFC-ACS than IFC-ACS and stable angina (96, 20, and 14; P 0.001). However, none of the specific CT angiography features clearly distinguished IFC-ACS from stable lesions. ConclusionIn contrast to the situation with RFC-ACS, distinct culprit lesion characteristics associated with non-rupture-related mechanisms are not identified by CT angiography. It will therefore not be possible to differentiate plaques likely to develop IFC-ACS from stable plaques.

The fate of incomplete stent apposition with drug-eluting stents: An optical coherence tomography-based natural history study (Article)

2010-06-01T00:00:00Z

Aims To assess the fate of incomplete stent apposition (ISA) after deployment of sirolimus-eluting stents (SESs).Methods and resultsThirty-two patients having intravascular ultrasound (IVUS)-guided PCI with SESs underwent assessment of stent deployment with quantitative coronary angiography, IVUS, and optical coherence tomography (OCT) pre-procedure, post-procedure, and at 10 months follow-up. Incomplete stent apposition was defined as separation of a stent strut from the inner vessel wall by >160 m. At follow-up, 4.67 of struts with ISA at deployment failed to heal and 7.59 which were well apposed did not develop neointimal hyperplasia even after 10 months. Lesion remodelling was responsible for the development of late ISA in only 0.37 of struts. Failure of adequate neointimal hyperplasia was quantitatively the most important mechanism responsible for persistent acute ISA, classified in previous studies, which relied only on follow-up OCT, as late ISA. Thrombus was visualized in 20.6 of struts with ISA at follow-up and in 2.0 of struts with a good apposition (P < 0.001).ConclusionIn patients with SESs, ISA can fail to heal and even complete apposition can be associated with no neointimal hyperplasia. Incomplete stent apposition without neointimal hyperplasia was significantly associated with the presence of OCT-detected thrombus at follow-up, and may constitute a potent substrate for late stent thrombosis

Expert review document on methodology, terminology, and clinical applications of optical coherence tomography: Physical principles, methodology of image acquisition, and clinical application for assessment of coronary arteries and atherosclerosis (Article)

2010-02-01T00:00:00Z

Optical coherence tomography (OCT) is a novel intravascular imaging modality, based on infrared light emission, that enables a high resolution arterial wall imaging, in the range of 10-20 microns. This feature of OCT allows the visualization of specific components of the atherosclerotic plaques. The aim of the present Expert Review Document is to address the methodology, terminology and clinical applications of OCT for qualitative and quantitative assessment of coronary arteries and atherosclerosis.

Clinical Application of Intracoronary Ultrasound (IVUS) and Quantitative Coronary Angiography (QCA) to Assess Coronary Intervention and Atherosclerosis (Doctoral Thesis)

2005-02-09T00:00:00Z

Ischemic heart disease remains a major cause of mortality and morbidity in Europe, the United States and Japan. It has been proposed that coronary atherosclerosis is the consequence of the vascular response to injurious effects of exposure to the classical cardiovascular risk factors including smoking, diabetes, hypertension and hyperlipidemia. However, the relationship between such coronary risk factors and atherosclerotic coronary plaque burden has not yet been fully elucidated. The epidemic of cardiovascular disease demands further efforts to elucidate the mechanisms of atherosclerosis and further research to develop and guide treatments. Since Andreas R. Grüntzig performed the first percutaneous transluminal coronary angioplasty on September 16th 1977, coronary intervention has become accepted as an effective therapy for patients with coronary artery disease all over the world. The initial success achieved with percutaneous coronary intervention continues to be limited by restenosis. Intracoronary ultrasound (IVUS) studies reveal that late vessel remodeling and plaque growth plays an important role in the restenosis process. Coronary stenting, by supporting the vessel wall, limits early and late vessel remodeling and subsequently decreases restenosis. More recently short- to medium-term restenosis appears to have been further ameliorated by the advent of drug-eluting stent (DES) technologies. However, several limitations still restrict the widespread application of this technique including concerns about subacute or late stent thrombosis, the limited success rates of PCI for complex lesion morphology (e.g. chronic total occlusion (CTO)) and interventional cost. The ultimate goal of interventional cardiology is to disclose the mechanism of progression and regression of coronary atherosclerosis, and to provide less invasive and more effective treatments for the patients suffering from ischemic heart disease. Each interventional device should be carefully sized and deployed using reliable techniques such as intracoronary ultrasound (IVUS) and quantitative coronary angiography (QCA).

Comparison of Coronary Luminal Quantification Obtained From Intracoronary Ultrasound and Both Geometric and Videodensitometric Quantitative Angiography Before and After Balloon Angioplasty and Directional Atherectomy (Article)

1997-01-01T00:00:00Z

Background Debate exists regarding the relationship between angiographic and intracoronary ultrasound (ICUS) measurements of minimal luminal cross-sectional area after coronary intervention. We investigated this and the factors that may influence it by using ICUS and quantitative angiography. Methods and Results Patients who underwent successful balloon angioplasty (n=100) or directional atherectomy (n=50) were examined by using ICUS and quantitative angiography (edge-detection [ED] and videodensitometry [VID]) before and after intervention. Luminal damage postintervention was qualitatively graded into three categories based on angiographic results (smooth lumen, haziness, or dissection). Correlation of minimal luminal cross-sectional area measurements by ICUS and ED was .59 before and .47 after balloon angioplasty. Correlation between ICUS and VID was .50 before and .63 after balloon angioplasty. Postintervention, the difference between ICUS and VID was less than the difference between ICUS and ED (P<.01). Additionally, the correlation was .74 between ICUS and ED measurements and .78 between ICUS and VID measurements in the smooth lumen group, .46 and .63, respectively, in the presence of haziness, and .26 and .46, respectively, in lesions with dissection. Similar results were obtained after directional atherectomy: the agreement between ICUS and quantitative angiography deteriorated according to the degree of vessel damage, but less so with VID than ED. Conclusions Complex morphological changes induced by intervention may contribute to discordance between the two quantitative imaging techniques. In the absence of ICUS, VID may be a complementary technique to ED in lesions with complex morphology after balloon angioplasty and directional atherectomy.

Acute clinical and angiographic results with the new AVE Micro coronary stent in bailout management. (Article)

1995-07-27T00:00:00Z

To determine the feasibility and safety of development of this new stent, we deployed 28 AVE Micro stents in 23 native coronary artery lesions in 20 patients who developed acute or threatened closure after balloon angioplasty (BA). Ten stents were deployed in the left anterior descending artery, 10 in the circumflex, and 8 in the right coronary artery. Luminal dimensions were measured using a computer-based quantitative coronary angiographic analysis system (CAAS II). Stent deployment was successful in 27 of 28 attempts (96%). In 1 patient with a threatened closure of the left anterior descending artery associated with proximal vessel tortuosity, attempted stent deployment was unsuccessful. The clinical course of the other 19 patients in whom stent deployment was successful was free of coronary reintervention, bypass surgery, and death. A myocardial infarction was observed in 2 patients (10%), in 1 of whom the stent was implanted within 24 hours after the onset of acute myocardial infarction, and in the other acute vessel occlusion was present for 58 minutes before stent implantation. No subacute occlusion was observed. Event-free survival at 30 days after stent implantation was 85% (17 of 20 patients). Minimal luminal diameter was 0.85 +/- 0.57 mm before and 1.19 +/- 0.66 mm after BA, 2.61 +/- 0.39 mm during balloon inflation, 3.26 +/- 0.46 mm during and 2.74 +/- 0.51 mm after stenting, 3.43 +/- 0.52 mm during balloon inflation after stenting (Swiss Kiss), and 2.85 +/- 0.48 mm after Swiss Kiss.(ABSTRACT TRUNCATED AT 250 WORDS)

Coronary arteriography for quantitative analysis: experimental and clinical comparison of cinefilm and video recordings. (Article)

1995-03-01T00:00:00Z

Although use of videotape for the recording of coronary angiograms continues to grow, the validity of quantitative coronary angiographic analysis of video images remains unknown. To estimate the realibility of angiographic images recorded on videotapes, experimental and clinical angiograms were recorded simultaneously on both 35 mm cinefilm and super-VHS videotape with normal images and with spatial filtering of the images (edge enhancement) on a digital cardiac imaging system. The experimental angiographic studies were performed with plexiglass blocks and stenosdis phantom of 0.5 to 3.0 mm in diameter. The clinical angiograms were recorded in 20 patients undergoing percutaneous transluminal coronary angioplasty (31 frames before and 20 frames after percutaneous transluminal coronary angioplasty). The cinefilm and corresponding videotapes were analyzed off-line with the new version of the coronrary angiography analysis system. For the experimental study, measurements of minimal luminal diameter obtained from cinefilm, normal-image videotape, and edge-enhanced videotape were compared with the true phanton diameter. In the clinical study the agrrement between measurements obtained from cinefilm and measurements from normal-image videotape and edge-enhanced videotape was examined. In the phantom series the accuracy and precision of quantitative coronary angiography measurement for cinefilm were −0.10 ± 0.08 mm, for normal-image videotape −0.11 ± 0.18 mm, and for edge-enhanced videotape − 0.10 ± 0.11 mm (mean ± SD). In the clinical series, the differences between measurements from cinefilm and normal-image videotape were 0.14 ± 0.20 mm and from cinefilm and edge-enhanced videotape 0.04 ± 0.13 mm. In the experimental phantom study, the use of cinefilm resulted in the most precise measurements. In the clinical study, edge-enhanced videotape provided the highest agreement with measurements obtained from cinefilm. These findings suggest that cinefilm is moore reliable than video as a recording medium for quantitative coronary analysis in scientific studies; however, for routine practice, videotape and edge-enhanced images may provide an acceptable alternative.

Coronary lumen at six-month follow-up of a new radiopaque Cordis tantalum stent using quantitative angiography and intracoronary ultrasound. (Article)

1995-01-01T00:00:00Z

To determine the reliability of geometric (edge-detection) quantitative coronary angiographic analysis (QCA) of restenosis within a new Cordis tantalum stent, QCA and intracoronary ultrasound (ICUS) measurements were compared in both an experimental restenosis model and in the clinical follow-up of patients. In the experimental series, Plexiglas phantom vessels with concentric stenosis channels ranging from 0.75 to 3.0 mm in diameter and with a reference diameter of 3.0 mm were imaged both before and after their insertion in tantalum stents. In the clinical series, the agreement of QCA and ICUS measurements were studied in 23 patients who had undergone coronary implantation of the new tantalum stent and in 23 patients who had undergone balloon angioplasty 6 months previously. The reliability of QCA declined in the presence of the radiopaque stent (accuracy of QCA decreased from -0.07 to -0.12 mm), whereas the reliability of lumen measurements by ICUS was independent of the presence of the radiopaque stent (-0.12 and -0.13 mm). Without the stent, the average minimal luminal diameter (MLD) obtained by QCA of the 1.00 mm Plexiglas vessel was 1.00 +/- 0.01 mm, and the 3.00 mm reference vessel diameter was 2.81 +/- 0.05 mm, providing a 64 +/- 1% diameter stenosis. After introduction of the stent, the average MLD and reference vessel diameter were 0.99 +/- 0.06 and 3.36 +/- 0.17 mm, respectively, providing a diameter stenosis of 71 +/- 2%. ICUS measurements (2.77 mm) of the reference vessel diameter (3.00 mm) were unaffected by the presence of the stent. (ABSTRACT TRUNCATED AT 250 WORDS)

Ischemia-Related Lesion Characteristics in Patients With Stable or Unstable Angina (Article)

1995-01-01T00:00:00Z

Background Postmortem-derived findings support the common beliefs that lipid-rich coronary plaques with a thin, fibrous cap are prone to rupture and that rupture and superimposed thrombosis are the primary mechanisms causing acute coronary syndromes. In vivo imaging with intracoronary techniques may disclose differences in the characterization of atherosclerotic plaques in patients with stable or unstable angina and thus may provide clues to which plaques may rupture and whether rupture and thrombosis are active. Methods and Results We assessed the characteristics of the ischemia-related lesions with coronary angiography and intracoronary angioscopy and determined their compositions with intracoronary ultrasound in 44 patients with unstable and 23 patients with stable angina. The angiographic images were classified as noncomplex (smooth borders) or complex (irregular borders, multiple lesions, thrombus). Angioscopic images were classified as either stable (smooth surface) or thrombotic (red thrombus). The ultrasound characteristics of the lesion were classified as poorly echo-reflective, highly echo-reflective with shadowing, or highly echo-reflective without shadowing. There was a poor correlation between clinical status and angiographic findings. An angiographic complex lesion (n=33) was concordant with unstable angina in 55% (24 of 44); a noncomplex lesion (n=34) was concordant with stable angina in 61% (14 of 23). There was a good correlation between clinical status and angioscopic findings. An angioscopic thrombotic lesion (n=34) was concordant with unstable angina in 68% (30 of 44); a stable lesion (n=33) was concordant with stable angina in 83% (19 of 23). The ultrasound-obtained composition of the plaque was similar in patients with unstable and stable angina. Conclusions Angiography discriminates poorly between lesions in stable and unstable angina. Angioscopy demonstrated that plaque rupture and thrombosis were present in 17% of stable angina and 68% of unstable angina patients. Currently available ultrasound technology does not discriminate stable from unstable plaques.

Comparative validation of quantitative coronary angiography systems. Results and implications from a multicenter study using a standardized approach. (Article)

1995-01-01T00:00:00Z

Background Computerized quantitative coronary angiography (QCA) has fundamentally altered our approach to the assessment of coronary interventional techniques and strategies aimed at the prevention of recurrence and progression of stenosis. It is essential, therefore, that the performance of QCA systems, upon which much of our scientific understanding has become integrally dependent, is evaluated in an objective and uniform manner. Methods and Results We validated 10 QCA systems at core laboratories in North America and Europe. Cine films were made of phantom stenoses of known diameter (0.5 to 1.9 mm) under four experimental conditions: in vivo (coronary arteries of pigs) calibrated at the isocenter or by use of the catheter as a scaling device and in vitro with 50% contrast and 100% contrast. The cine films were analyzed by each automated QCA system without observer interaction. Accuracy and precision were taken as the mean and SD of the signed differences between the phantom stenoses, and the measured minimal luminal diameters and the correlation coefficient (r), the SEE, the y intercept, and the slope were derived by their linear regression. Performance of the 10 QCA systems ranged widely: accuracy, +0.07 to +0.31 mm; precision, ±0.14 to ±0.24 mm; correlation (r), .96 to .89; SEE, ±0.11 to ±0.16 mm; intercept, +0.08 to +0.31 mm; and slope, 0.86 to 0.64. Conclusions There is a marked variability in performance between systems when assessed over the range of 0.5 to 1.9 mm. The range of accuracy, intercept, and slope values of this report indicates that absolute measurements of luminal diameter from different multicenter angiographic trials may not be directly comparable and additionally suggests that such absolute measurements may not be directly applicable to clinical practice using an on-line QCA system with a different edge detection algorithm. Power calculations and study design of angiographic trials should be adjusted for the precision of the QCA system used to avoid the risk of failing to detect small differences in patient populations. This study may guide the fine-tuning of algorithms incorporated within each system and facilitate the maintenance of high standards of QCA for scientific studies.

Advantages and limitations of intracoronary ultrasound for the assessment of vascular dimensions (Article)

1994-02-01T00:00:00Z

Temporal variability and correlation with geometric parameters in vasospastic angina: a quantitative angiographic study (Article)

1994-01-01T00:00:00Z

Long-term changes in vasocontractility were examined in 23 coronary segments from 20 patients with variant angina using computer-based quantitative coronary angiography and ergonovine provocation tests repeated at an interval of 42 +/- 14 months. Measurements of vasospasticity at the sites of fixed stenoses were compared with values predicted by an elementary geometric theory based on the assumption that the cross-sectional area of a vessel wall is constant regardless of its state of vasoconstriction. While all patients were symptomatic initially, only 11 remained symptomatic at follow-up. At the initial provocation test, the response was correctly predicted in four segments, was lower than expected in one, and was stronger in 18. At follow-up, only one of the four segments in which the response had been initially predicted correctly again showed the predicted response and the remaining three showed a response weaker than expected; the one segment which was initially hypocontractile remained hypocontractile at follow-up; and of the 18 segments which were initially hypercontractile, 12 exhibited hypercontractility again, four had the predicted value and the remaining two showed hypocontractility. In only one of 23 segments did the geometric theory predict the behaviour of vasospasticity at the site of fixed stenosis on both tests. Vasospastic responsiveness is a dynamic process demonstrating temporal variability and is not directly predicted by geometric theory.

Experimental validation of geometric and dentitometric coronary measurements on the new generation cardiovascular angiography analysis system (CAAS II) (Article)

1993-01-01T00:00:00Z