Ormiston, J.A.

Head-to-head comparison of the neointimal response between metallic and bioresorbable everolimus-eluting scaffolds using optical coherence tomography (Article)

2011-12-01T00:00:00Z

The metallic everolimus drug-eluting stents (DES) and polymeric everolimus bioresorbable vascular scaffolds (BVS) are coated with the same antiproliferative drug. It is uncertain if, during the bioresorption process, the neointimal response of everolimus BVS differs from that of everolimus DES. A total of 31 lesions treated with a single everolimus BVS, and 19 lesions treated with everolimus DES and imaged with optical coherence tomography at 1 year, were investigated. Neointimal response was assessed as a percentage of uncovered struts, neointimal thickness, in-stent/scaffold area obstruction, and pattern of neointima. Both scaffolds presented with similar neointimal response. However, the everolimus BVS presented with a trend toward higher proportion of intraluminal masses than everolimus DES did. This study sought to compare the neointimal response of metallic everolimus drug-eluting stents (DES) and polymeric everolimus bioresorbable vascular scaffolds (BVS) by optical coherence tomography at 1 year. DES decrease the risk of restenosis by reducing the neointimal response. However, DES may impair strut coverage, and this has been associated with late stent/scaffold thrombosis. BVS may overcome the risk of stent/scaffold thrombosis when completely resorbed. It is unknown if, during the bioresorption process, the neointimal response of the everolimus BVS (Absorb, Abbott Vascular, Santa Clara, California) differs from that of the metallic everolimus DES (Xience, Abbott Vascular). A total of 19 lesions were treated with a single everolimus DES, and 31 lesions were treated with everolimus BVS and imaged with optical coherence tomography at 1 year. Neointimal response was assessed as percentage of uncovered struts, neointimal thickness, in-stent/scaffold area obstruction, and pattern of neointima. At 1 year, no significant differences in the angiographic lumen loss were seen for the everolimus DES and everolimus BVS (0.18 ± 0.20 mm vs. 0.29 ± 0.36 mm; p = 0.42). optical coherence tomography analysis of 951 cross sections and 8,385 struts demonstrated similar rates of uncovered struts (5.3% everolimus DES vs. 4.5% everolimus BVS; p = 0.11), mean neointimal thickness (120.6 ± 46.0 μm vs. 136.1 ± 71.4 μm; p = 0.82) and in-stent/scaffold area obstruction (12.5 ± 7.1% vs. 13.6 ± 9.7%; p = 0.91), respectively. There was a trend of higher heterogenic tissue pattern of neointima (21.1% vs. 6.5%; p = 0.12) and less intraluminal masses (0% vs. 12.9%; p = 0.10) with everolimus DES than with everolimus BVS. The everolimus BVS (Absorb) demonstrated a similar neointimal response as the everolimus DES (Xience). However, the presence of intraluminal masses at 12 months in a small proportion of patients warranted watchful follow-up of these cases.

Serial in vivo intravascular ultrasound-based echogenicity changes of everolimus-eluting bioresorbable vascular scaffold during the first 12 months after implantation: Insights from the ABSORB B trial (Article)

2011-12-01T00:00:00Z

Because the bioresorption of the ABSORB bioresorbable vascular scaffold (Abbott Vascular, Santa Clara, California) is characterized by a diminishing gray-level intensity of the struts over time, the evaluation of quantitative changes in hyperechogenicity can be useful to follow the in vivo degradation of the scaffold. Whereas the first ABSORB generation showed at 6 months a 50% reduction in hyperechogenicity, the second ABSORB generation (1.1), designed to prolong the duration of luminal scaffolding, showed a 15% and 20% reduction in hyperechogenicity at 6 and 12 months, respectively, compared with post-implantation. These findings confirm the value of the manufacturing changes and suggest a slower degradation rate of the scaffold. This study sought to investigate quantitative and homogeneity differential echogenicity changes of the ABSORB scaffold (1.1) during the first year after implantation. The imaging of the ABSORB bioresorbable vascular scaffold degradation by intravascular ultrasound (IVUS) has previously demonstrated diminishing gray-level intensity of the struts over time that can be evaluated by IVUS-based differential echogenicity. The first generation of ABSORB (1.0) showed a 50% reduction in hyperechogenicity at 6 months and restoration of the pre-ABSORB implantation values at 2 years. The second generation of ABSORB (1.1), investigated in the ABSORB B trial, was modified to prolong the duration of luminal scaffolding. A total of 63 patients were examined by IVUS immediately post-implantation and at 6-month (Cohort B1, n = 28) or 12-month (Cohort B2, n = 35) follow-up. IVUS-based tissue composition analysis software was used to quantify changes in hyperechogenicity over time in the scaffolded regions. Relative changes in hyperechogenicity were calculated as: 100 × (% hyperechogenicity at follow-up - % hyperechogenicity at baseline)/% hyperechogenicity at baseline. At 6- and 12-month follow-up, there was a 15% (from 22.58 ± 9.77% to 17.42 ± 6.69%, p = 0.001) and 20% (from 23.51 ± 8.57% to 18.25 ± 7.19%, p < 0.001) reduction in hyperechogenicity, respectively, compared with post-implantation values. No difference in hyperechogenicity changes were observed between the proximal, medial, or distal part of the scaffolded segment. Quantitative differential echogenicity changes of the ABSORB scaffold (1.1) during the first 12 months after implantation are lower compared with those previously observed with its first generation (1.0), confirming the value of the manufacturing changes and suggesting a slower degradation rate of the scaffold.

Analysis of 1 year virtual histology changes in coronary plaque located behind the struts of the everolimus eluting bioresorbable vascular scaffold (Article)

2011-11-24T00:00:00Z

Serial intravascular ultrasound virtual histology (IVUS-VH) after implantation of metallic stents has been unable to show any changes in the composition of the scaffolded plaque overtime. The everolimus-eluting ABSORB scaffold potentially allows for the formation of new fibrotic tissue on the scaffolded coronary plaque during bioresorption. We examined the 12 month IVUS-VH changes in composition of the plaque behind the struts (PBS) following the implantation of the ABSORB scaffold. Using IVUS-VH and dedicated software, the composition of the PBS was analyzed in all patients from the ABSORB Cohort B2 trial, who were imaged with a commercially available IVUS-VH console (s5i system, Volcano Corporation, Rancho Cordova, CA, USA), immediately post-ABSORB implantation and at 12 month follow-up. Paired IVUS-VH data, recorded with s5i system, were available in 17 patients (18 lesions). The analysis demonstrated an increase in mean PBS area (2.39 ± 1.85 mm2vs. 2.76 ± 1.79 mm2, P = 0.078) and a reduction in the mean lumen area (6.37 ± 0.90 mm2vs. 5.98 ± 0.97 mm2, P = 0.006). Conversely, a significant decrease of 16 and 30% in necrotic core (NC) and dense calcium (DC) content, respectively, were evident (median % NC from 43.24 to 36.06%, P = 0.016; median % DC from 20.28 to 11.36%, P = 0.002). Serial IVUS-VH analyses of plaque located behind the ABSORB struts at 12-month demonstrated an increase in plaque area with a decrease in its NC and DC content. Larger studies are required to investigate the clinical impact of these findings.

Evaluation of the second generation of a bioresorbable everolimus-eluting vascular scaffold for the treatment of de Novo Coronary Artery stenosis: 12-month clinical and imaging outcomes (Article)

2011-10-04T00:00:00Z

Objectives: The aim of this study was to demonstrate that the prevention of early scaffold area shrinkage of the ABSORB BVS (Rev.1.1, Abbott Vascular, Santa Clara, California) was sustained and not simply delayed by a few months. Background: With improved scaffold design and modified manufacturing process of its polymer, the second iteration of ABSORB (BVS 1.1) has improved performance to prevent a scaffold area reduction at 6 months. Methods: Fifty-six patients were enrolled and received 57 ABSORB scaffolds. Quantitative coronary angiography, intravascular ultrasound (IVUS), analysis of radiofrequency backscattering, echogenicity and optical coherence tomography (OCT) were performed at baseline and at 12-month follow-up. Results: Overall the scaffold area remained unchanged with IVUS as well as with OCT, whereas the radiofrequency backscattering and the echogenicity of the struts decreased by 16.8% (p < 0.001) and 20% (p < 0.001), respectively; more specifically, the strut core area on OCT decreased by 11.4% (p = 0.003). Despite the absence of scaffold area loss, pharmacological vasomotion was restored. On an intention-to-treat basis, the angiographic late lumen loss amounted to 0.27 ± 0.32 mm with an IVUS relative decrease in minimal lumen area of 1.94% (p = 0.12), without significant changes in mean lumen area. The OCT at follow-up showed that 96.69% of the struts were covered and that malapposition, initially observed in 18 scaffolds was only detected at follow-up in 4 scaffolds. Two patients experienced peri-procedural and iatrogenic myocardial infarction, respectively, whereas 2 underwent repeat intervention, resulting in the major adverse cardiac event rate of 7.1% (4 of 56). Conclusions: The 12-month performance of the second-generation ABSORB bioresorbable everolimus-eluting scaffold justifies the conduct of a randomized trial against current best standards. (A Clinical Evaluation of the Bioabsorbable Everolimus Eluting Coronary Stent System [BVS EECSS] in the Treatment of Patients With de Novo Native Coronary Artery Lesions; NCT00856856)

Serial analysis of the malapposed and uncovered struts of the new generation of everolimus-eluting bioresorbable scaffold with optical coherence tomography (Article)

2011-09-01T00:00:00Z

Objectives: The aim of this study is to assess the serial changes in strut apposition and coverage of the bioresorbable vascular scaffolds (BVS) and to relate this with the presence of intraluminal masses at 6 months with optical coherence tomography (OCT). Background: Incomplete strut/scaffold apposition (ISA) and uncovered struts are related to a higher risk of scaffold thrombosis. Bioresorbable vascular scaffolds can potentially avoid the risk of scaffold thrombosis because of its complete resorption. However, during the resorption period, the risk of scaffold thrombosis is unknown. Methods: OCT was performed in 25 patients at baseline and 6 months. Struts were classified according to apposition, coverage, and presence of intraluminal masses. Persistent ISA was defined as malapposed struts present at baseline and follow-up, and late acquired ISA as ISA developing at follow-up, and scaffold pattern irregularities when the strut distribution suggested scaffold fracture. Results: At baseline, 3,686 struts were analyzed: 128 (4%) were ISA, and 53 (1%) were located over side-branches (SB). At 6 months, 3,905 struts were analyzed: 32 (1%) ISA, and 35 (1%) at the SB. Persistent ISA was observed more frequently than late acquired-ISA (81% vs. 16%, respectively; 3% were unmatchable). Late acquired ISA was associated with scaffold pattern irregularities, which were related to overstretching of the scaffold. Uncovered struts (63 struts, 2%) were more frequently observed in ISA and SB struts, compared with apposed struts (29% vs. 1%; p < 0.01). Intraluminal masses (14 cross-sections, 3%; in 6 patients, 24%) were more frequently located at the site of ISA and/or uncovered struts (39% vs. 2% and 13% vs. 2%, respectively; p < 0.01). Conclusions: The lack of strut apposition at baseline is related to the presence of uncovered struts and intraluminal masses at 6 month. An appropriate balloon/artery ratio respecting the actual vessel size and avoiding the overstretching of the scaffold can potentially decrease the risk of scaffold thrombosis. (ABSORB Clinical Investigation, Cohort B [ABSORB B]; NCT00856856)

6-month clinical outcomes following implantation of the bioresorbable everolimus-eluting vascular scaffold in vessels smaller or larger than 2.5 mm (Article)

2011-07-12T00:00:00Z

Objectives: We investigated the 6-month clinical outcomes after implantation of second-generation 3.0-mm bioresorbable everolimus-eluting vascular scaffolds (BVS) in small coronary vessels (<2.5 mm). Background: BVS are a novel approach to treating coronary lesions and are untested in small vessels. Methods: The ABSORB Cohort B Trial is a multicenter, single-arm, prospective, open-label trial assessing the performance of the second-generation BVS, in which 101 patients were enrolled. The pre-procedural reference vessel diameter (RVD) was assessed by quantitative coronary angiography during post hoc analysis. The vessel size was overestimated, by visual assessment, in 41 patients before implantation of 3.0-mm BVS in vessels with a pre-procedural RVD <2.5 mm. The study population was divided into 2 groups, group I (n = 41) with RVD <2.5 mm and group II (n = 60) with RVD <2.5 mm. The composite endpoint of ischemia-driven major adverse cardiac events, defined as ischemia-driven target lesion revascularization, myocardial infarction, or cardiac death, was assessed. Of the 45 patients scheduled for 6-month coronary angiography, 42 patients had the procedure performed, with intravascular ultrasound undertaken in 40 of these patients. Results: At 6 months, no significant differences in ischemia-driven major adverse cardiac events (3 of 41 [7.3%] cases vs. 2 of 60 [3.3%] cases; p = 0.3933) were observed in the small- and large-vessel groups, respectively. No cardiac deaths or episodes of in-scaffold thromboses were seen. Angiographic and intravascular ultrasound follow-up demonstrated no differences in late lumen loss (0.16 ± 0.18 mm vs. 0.21 ± 0.17 mm; p = 0.3525) or percentage lumen area stenosis (17.6 ± 6.0% vs. 19.8 ± 8.5%; p = 0.3643). Conclusions: The second-generation 3.0-mm BVS appears to be safe in small vessels, with similar clinical and angiographic outcomes compared with those of large vessels.

Comparison of in vivo acute stent recoil between the bioresorbable everolimus-eluting coronary scaffolds (revision 1.0 and 1.1) and the metallic everolimus-eluting stent (Article)

2011-07-01T00:00:00Z

Objectives: The ABSORB cohort A trial using the bioresorbable everolimus-eluting scaffold (BVS revision 1.0, Abbott Vascular) demonstrated a slightly higher acute recoil with BVS than with metallic stents. To reinforce the mechanical strength of the scaffold, the new BVS scaffold (revision 1.1) with modified strut design was developed and tested in the ABSORB cohort B trial. This study sought to evaluate and compare the in vivo acute scaffold recoil of the BVS revision 1.0 in ABSORB cohort A and the BVS revision 1.1 in ABSORB cohort B with the historical recoil of the XIENCE V® everolimus-eluting metal stent (EES, SPIRIT I and II). Methods: In the ABSORB cohort B trial, 101 patients with one or two de-novo lesions were enrolled at 10 sites. In ABSORB cohort A, 27 patients treated with a BVS 1.0 were analyzed and compared with EES. Acute absolute recoil, assessed by quantitative coronary angiography, was defined as the difference between mean diameter of the last inflated balloon at the highest pressure (X) and mean lumen diameter of the stent immediately after the last balloon deflation (Y). Acute percent recoil was defined as (X - Y)/X and expressed as a percentage. Results: Out of 101 patients enrolled in the ABSORB cohort B trial, 88 patients are available for complete analysis of acute recoil. Absolute recoil of BVS 1.1 (0.19 ± 0.18 mm) was numerically higher than metallic EES (vs. 0.13 ± 0.21 mm) and similar to BVS 1.0 (0.20 ± 0.21 mm) but the differences did not reach statistical significance (P = 0.40). The acute percent recoil demonstrated the same trend (EES: 4.3% ± 7.1%, BVS 1.0: 6.9% ± 7.0%, BVS 1.1: 6.7% ± 6.4%, P = 0.22). In the multivariate regression model, high balloon/artery ratio (>1.1) (OR 1.91 [1.34-2.71]) was the predictive for high absolute recoil (>0.27 mm) while (larger) preprocedural MLD was protective (OR 0.84 [0.72-0.99]). The stent/scaffold type was not a predictor of acute recoil. Conclusions: The average in vivo acute scaffold recoil of the BVS 1.1 is slightly higher than the metallic EES. However, the scaffold/stent type was not predictive of high acute recoil, while implantation in undersized vessels or usage of oversized devices might confound the results. Copyright

Angiographic geometric changes of the lumen arterial wall after bioresorbable vascular scaffolds and metallic platform stents at 1-year follow-up (Article)

2011-07-01T00:00:00Z

Objectives: The aim of this study was to compare the angiographic changes in coronary geometry of the bioresorbable vascular scaffolds (BVS) and metallic platform stent (MPS) between baseline and follow-up. Background: Coronary geometry changes after stenting might result in wall shear stress changes and adverse events. The BVS have better conformability, compared with MPS, but still modify artery geometry. It is uncertain whether the BVS resorption can restore the coronary anatomical configuration at midterm follow-up. Methods: All patients of the ABSORB (A Clinical Evaluation of the Bioabsorbable Everolimus Eluting Coronary Stent System [BVS EECSS] in the Treatment of Patients With de Novo Native Coronary Artery Lesions) and SPIRIT (A Clinical Evaluation of the XIENCE V Everolimus Eluting Coronary Stent System in the Treatment of Patients With de Novo Native Coronary Artery Lesions) trials treated with a single 3.0 × 18 mm device and imaged at baseline and 6- to 12-month follow-up were eligible. Coronary geometry changes were assessed with quantitative angiography as changes in curvature and angulation. Curvature and angulation changes between systole and diastole were investigated to assess hinging movements of the coronary artery. Results: One hundred sixty-one patients (86 BVS, and 75 MPS) were included. Baseline angiographic characteristics were similar. From post-implantation to follow-up, curvature increased 8.4% (p < 0.01) with BVS and decreased 1.9% (p = 0.54) with MPS; p = 0.01. Angulation increased 11.3% with BVS (p < 0.01) and 3.8% with MPS (p = 0.01); p < 0.01. From pre-implantation to follow-up, BVS decreased 3.4% the artery curvature (p = 0.05) and 3.9% the artery angulation (p = 0.16), whereas MPS presented with 26.1% decrease in curvature (p < 0.01) and 26.9% decrease in angulation (p < 0.01), being larger with MPS (p < 0.01, both). Hinging movements in curvature from pre-implantation to follow-up decreased 19.7% with BVS and 39.0% with MPS (p = 0.27) and decreased 3.9% with BVS and 26.9% with MPS in angulation (p < 0.01). Conclusions: At midterm follow-up, the BVS tended to restore the coronary configuration and the systo-diastolic movements to those seen before implantation. The coronary geometry remained similar to that seen at after implantation with MPS. (A Clinical Evaluation of the Bioabsorbable Everolimus Eluting Coronary Stent System [BVS EECSS] in the Treatment of Patients With de Novo Native Coronary Artery Lesions; NCT00856856)

Bioresorbable scaffold technologies (Article)

2011-03-11T00:00:00Z

Fully bioabsorbable scaffolds (BRS) are a novel approach that provides transient vessel support with drug delivery capability without the long-term limitations of the metallic drug-eluting stents (DES), such as permanent caging with or without malapposition. The technology has the potential to overcome many of the safety concerns associated with metallic DES, and possibly even convey further clinical benefit. Although the technology is still in its infancy, several devices have been tested in clinical trials and the initial results have been very promising. This review will discuss the emerging need for BRS, the theoretical advantages of this new technology over current generation metallic DES and review the status of the currently available BRS. In addition, we will discuss the ideal duration of bioresorption, the proven and potential clinical benefits and future perspectives of this rapidly progressing technology.

Morphological and functional evaluation of the bioresorption of the bioresorbable everolimus-eluting vascular scaffold using IVUS, echogenicity and vasomotion testing at two year follow-up: a patient level insight into the ABSORB A clinical trial (Article)

2010-12-01T00:00:00Z

The aim of this study was to describe vaso-reactivity (by Acetylcholine and Methergine tests) at 2 year follow-up in parallel with the individual changes in the echogenicity characteristics of the polymer struts of the everolimus eluting bioresorbable vascular scaffold (BVS), from post-treatment to 2 year follow-up, in patients enrolled in the ABSORB Cohort A study. Intravascular ultrasound assessment was performed with a phased array catheter (EagleEye, Volcano Corporation, Cordova, CA, USA) with automated pullback at 0.5 mm per second. The % ratio at 6 months and 2 years [(Scaffold Area post PCI- Lumen Area)/Scaffold Area post PCI] was calculated as a measure of scaffold shrinkage. The % change of hyperechogenicity was defined as: ([post-procedural hyperechogenicity] - [2 year follow up hyperechogenicity])/[post-procedural hyperechogenicity]) × 100. The vasomotion test with intracoronary acetylcholine (10-6M) or intravenous methergine (0.4 mg) was performed at 2 years. Overall nine patients received all these analyses and were enrolled in the present analysis. A 50-96% reduction in hyperechogenicity was observed between baseline and 2 years, which corresponded to a change in vasoreactivity between 2 and 22%. A vasoconstriction of the scaffolded segment was observed in the 5 patients, who underwent the methergine test, with a mean decrease in lumen diameter after methergine of 9 ± 7% (P = 0.06), while vasodilatation occurred in the 4 patients who underwent the acetylcholine test with a mean increase in lumen diameter after acetylcholine of 8 ± 5% (P = 0.125). Bioresorption of the BVS is accompanied by re-establishment of both endothelial and non-endothelial dependent vasomotion.

Evaluation of the second generation of a bioresorbable everolimus drug-eluting vascular scaffold for treatment of de novo coronary artery stenosis: Six-month clinical and imaging outcomes (Article)

2010-11-30T00:00:00Z

Background-: The first generation of the bioresorbable everolimus drug-eluting vascular scaffold showed signs of shrinkage at 6 months, which largely contributed to late luminal loss. Nevertheless, late luminal loss was less than that observed with bare metal stents. To maintain the mechanical integrity of the device up to 6 months, the scaffold design and manufacturing process of its polymer were modified. Methods and results-: Quantitative coronary angiography, intravascular ultrasound with analysis of radiofrequency backscattering, and as an optional assessment, optical coherence tomography (OCT) were performed at baseline and at a 6-month follow-up. Forty-five patients successfully received a single bioresorbable everolimus drug-eluting vascular scaffold. One patient had postprocedural release of myocardial enzyme without Q-wave occurrence; 1 patient with OCT-diagnosed disruption of the scaffold caused by excessive postdilatation was treated 1 month later with a metallic drug-eluting stent. At follow-up, 3 patients declined recatheterization, 42 patients had quantitative coronary angiography, 37 had quantitative intravascular ultrasound, and 25 had OCT. Quantitative coronary angiography disclosed 1 edge restenosis (1 of 42; in-segment binary restenosis, 2.4%). At variance with the ultrasonic changes seen with the first generation of bioresorbable everolimus drug-eluting vascular scaffold at 6 months, the backscattering of the polymeric struts did not decrease over time, the scaffold area was reduced by only 2.0% with intravascular ultrasound, and no change was noted with OCT. On an intention-to-treat basis, the late lumen loss amounted to 0.19±0.18 mm with a limited relative decrease in minimal luminal area of 5.4% on intravascular ultrasound. OCT showed at follow-up that 96.8% of the struts were covered and that malapposition of at least 1 strut, initially observed in 12 scaffolds, was detected at follow-up in only 3 scaffolds. Mean neointimal growth measured by OCT between and on top of the polymeric struts equaled 1.25 mm, or 16.6% of the scaffold area. Conclusion-: Modified manufacturing process of the polymer and geometric changes in the polymeric platform have substantially improved the medium-term performance of this new generation of drug-eluting scaffold to become comparable to those of current drug eluting stents.

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.

A comparison of the conformability of everolimus-eluting bioresorbable vascular scaffolds to metal platform coronary stents (Article)

2010-11-01T00:00:00Z

Objectives The aim of this study was to assess the differences in terms of curvature and angulation of the treated vessel after the deployment of either a metallic stent or a polymeric scaffold device. Background Conformability of metallic platform stents (MPS) is the major determinant of geometric changes in coronary arteries caused by the stent deployment. It is not known how bioresorbable polymeric devices perform in this setting. Methods This retrospective study compares 102 patients who received an MPS (Multi-link Vision or Xience V, Abbott Vascular, Santa Clara, California) in the SPIRIT FIRST and II trials with 89 patients treated with the Revision 1.1 everolimus-eluting bioresorbable vascular scaffold (BVS) (Abbott Vascular, Santa Clara, California) from cohort B of the ABSORB (A bioabsorbable everolimus-eluting coronary stent system) trial. All patients were treated with a single 3 × 18 mm device. Curvature and angulation were measured with dedicated software by angiography. Results Both the MPS and BVS groups had significant changes in relative region curvature (MPS vs. BVS: 28.7% vs. 7.5%) and angulation (MPS vs. BVS: 25.4% vs. 13.4%) after deployment. The unadjusted comparisons between the 2 groups showed for BVS a nonsignificant trend for less change in region curvature after deployment (MPS vs. BVS: 0.085 cm-1 vs. 0.056 cm-1, p = 0.06) and a significantly lower modification of angulation (MPS vs. BVS 6.4° vs. 4.3°, p = 0.03). By multivariate regression analysis, the independent predictors of changes in curvature and angulation were the pre-treatment region curvature, the pre-treatment region angulation, and the used device. Conclusions Bioresorbable vascular scaffolds have better conformability than conventional MPS. The clinical significance of the observed differences will require further investigation.

Temporal changes of coronary artery plaque located behind the struts of the everolimus eluting bioresorbable vascular scaffold (Article)

2010-10-13T00:00:00Z

Implantation of a coronary stent results in a mechanical enlargement of the coronary lumen with stretching of the surrounding atherosclerotic plaque. Using intravascular ultrasound virtual-histology (IVUS-VH) we examined the temporal changes in composition of the plaque behind the struts (PBS) following the implantation of the everolimus eluting bioresorbable vascular scaffold (BVS). Using IVUS-VH and dedicated software, the composition of plaque was analyzed in all patients from the ABSORB B trial who were imaged with a commercially available IVUS-VH console (s5i system, Volcano Corporation, Rancho Cordova, CA, USA) post-treatment and at 6-month follow-up. This dedicated software enabled analysis of the PBS after subtraction of the VH signal generated by the struts. The presence of necrotic core (NC) in contact with the lumen was also evaluated at baseline and follow-up. IVUS-VH data, recorded with s5i system, were available at baseline and 6-month follow-up in 15 patients and demonstrated an increase in both the area of PBS (2.45 ± 1.93 mm2vs. 3.19 ± 2.48 mm2, P = 0.005) and the external elastic membrane area (13.76 ± 4.07 mm2vs. 14.76 ± 4.56 mm2, P = 0.006). Compared to baseline there was a significant progression in the NC (0.85 ± 0.70 mm2vs. 1.21 ± 0.92 mm2, P = 0.010) and fibrous tissue area (0.88 ± 0.79 mm2vs. 1.15 ± 1.05 mm2, P = 0.027) of the PBS. The NC in contact with the lumen in the treated segment did not increase with follow-up (7.33 vs. 6.36%, P = 0.2). Serial IVUS-VH analysis of BVS-treated lesions at 6-month demonstrated a progression in the NC and fibrous tissue content of PBS.

3-dimensional optical coherence tomography assessment of jailed side branches by bioresorbable vascular scaffolds: A proposal for classification (Article)

2010-08-01T00:00:00Z

Objectives The purpose of this study is to assess jailing of side branches (SB) by the everolimuseluting, bioresorbable vascular scaffold (BVS) with 3-dimensional (3D) optical coherence tomography (OCT) reconstruction. Background Because BVS struts at the SB orifice are suspected of being bioresorbed and/or forming a neointimal bridge, OCT has been used to evaluate the struts in detail at that particular site. Our understanding of the 3D relationship of the strut and the SB orifice is limited by the use of 2-dimensional OCT images. Fourier-domain OCT enables reliable 3D reconstruction of coronary vessels. Methods The ABSORB Cohort B (A Clinical Evaluation of the Bioabsorbable Everolimus Eluting Coronary Stent System in the Treatment of Patients With de Novo Native Coronary Artery Lesions) trial is a multicenter single-arm trial to assess the safety and performance of the BVS. Fourier-domain OCT pullbacks (C7-XR system, LightLab Imaging Inc., Westford, Massachusetts) are obtained at pullback speed of 20 mm/s and 3D renderings are performed. The orifices of the SB are assessed visually. The area of SB orifice and the number of strut-free compartments delineated by the BVS struts are evaluated. Results Fifty-one OCT pullbacks were acquired: 33 pullbacks were imaged with Fourier-domain OCT and 27 treated segments had 46 side branches. Three-dimensional assessment was feasible in 87% (40 of 46) of pullbacks. The mean area of the SB orifice was 1.16 ± 1.02 mm2. The mean number of strut-free compartments was 2.0 ± 1.1. The classification of the overhanging struts is proposed. Conclusions This study demonstrates that 3D OCT reconstruction is feasible to evaluate the orifices of SB jailed with BVS.

IVUS radiofrequency analysis in the evaluation of the polymeric struts of the bioabsorbable everolimus-eluting device during the bioabsorption process (Article)

2010-05-01T00:00:00Z

Background: In the ABSORB study cohort A the changes in the amount of dense calcium and necrotic core have not been reported in comparison to the prestenting phase; this evaluation could be useful to better clarify the bioabsorption process. Aim of this study was therefore to evaluate the dynamic changes in plaque size and plaque tissue composition observed between 6 months and 2 years follow-up, and to compare these findings to the prestenting phase. Methods: Angiography, intravascular ultrasound and derived parameters (virtual histology, palpography, and echogenicity) were serially assessed postprocedure, at 6 months and at 2 years in 20 patients. In a subset of 8 patients the same measurements were also recorded in the prestenting phase. Results: In the total population a reduction of 18% in the plaque area was observed between 6 month and 2 year follow-up (7.56 ± 2.32 mm2at 6 months vs. 6.16 ± 2.10 mm2at 2 year follow-up; P < 0.01). In the subgroup of eight patients who underwent IVUS during the pre-stenting phase, the plaque area at 2 year follow-up was not significantly different when compared to the prestenting plaque area (7.29 ± 2.29 mm2at prestenting vs. 7.48 ± 1.45 mm2at 2 year follow-up, P 5 NS). Necrotic core area was reduced by 24% between the 6 month and 2 year follow-up (0.97 ± 0.66 mm2at 6 months vs. 0.74 ± 0.53 mm2at 2 year follow-up; P 5 NS), whilst dense calcium was reduced by 14% from 6 month to 2 year follow-up (0.83 ± 0.50 mm2at 6 months vs 0.72 ± 0.64 mm2at 2 year follow-up; P 5 NS). Whilst the necrotic core at 2 years follow-up was not significantly different when compared to the pre-stenting phase (0.62 ± 0.42 mm2prestenting vs 1.07 ± 0.56 mm2at 2 year follow-up; P 5 NS), the area of dense calcium was significantly higher at follow-up compared to prestenting (0.35 ± 0.35 mm2pre-stenting vs. 0.84 ± 0.66 mm2at 2 year follow-up; P < 0.05). Conclusions: The reduction in the necrotic core component between 6 month and two year followup could be related to a synergistic effect of the bio-absorption process and the antiinflammatory action of everolimus.

Monitoring in vivo absorption of a drug-eluting bioabsorbable stent with intravascular ultrasound-derived parameters: A feasibility study (Article)

2010-03-01T00:00:00Z

Objectives: The aim of this study was to investigate the feasibility of using quantitative differential echogenicity to monitor the in vivo absorption process of a drug-eluting poly-l-lactic-acid (PLLA) bioabsorbable stent (BVS, Abbott Vascular, Santa Clara, CA). Background: A new bioabsorbable, balloon-expanded coronary stent was recently evaluated in a first-in-man study. Little is known about the absorption process in vivo in diseased human coronary arteries. Methods: In the ABSORB (Clinical Evaluation of the BVS everolimus eluting stent system) study, 30 patients underwent treatment with the BVS coronary stent system and were examined with intracoronary ultrasound (ICUS) after implantation, at 6 months and at 2-year follow-up. Quantitative ICUS was used to measure dimensional changes, and automated ICUS-based tissue composition software (differential echogenicity) was used to quantify plaque compositional changes over time in the treated regions. Results: The BVS struts appeared as bright hyperechogenic structures and showed a continuous decrease of their echogenicity over time, most likely due to the polymer degradation process. In 12 patients in whom pre-implantation ICUS was available, at 2 years the percentage-hyperechogenic tissue was close to pre-implantation values, indicating that the absorption process was either completed or the remaining material was no longer differentially echogenic from surrounding tissues. Conclusions: Quantitative differential echogenicity is a useful plaque compositional measurement tool. Furthermore, it seems to be valuable for monitoring the absorption process of bioabsorbable coronary stents made of semi-crystalline polymers.

Bioabsorbable coronary stents (Article)

2009-06-01T00:00:00Z

An ideal stent should furnish best acute outcomes after PCI by sealing intimal flaps and optimizing lumen size. It should control restenosis by limiting negative remodeling and by controlling excessive healing by delivery of an antiproliferative drug. Beyond 6 months, a permanent implant has no useful function and has possible disadvantages including the potential for late thrombosis. The concept of a stent that does its job and disappears has appeal.44 A number of different materials ranging from magnesium to a variety of polymers have been used to construct stents of different designs. Some of these are being tested in clinical trials. The best outcomes to date have been with the BVS everolimus-eluting PLLA stent where in the Absorb trial, cohort A at 2 years, the stent was safe in the small number of patients with simple lesions.9,11 Indeed, there is a suggestion of luminal enlargement between 6 months and 2 years, return of vasomotion, and endothelial function. These findings need to be confirmed in larger trials in more complex lesions. A hope is that a healed, normally functioning vessel free of foreign body and restenosis will be free of the risk of late thrombosis. Time will tell if this dream will come true.

A bioabsorbable everolimus-eluting coronary stent system (ABSORB): 2-year outcomes and results from multiple imaging methods (Article)

2009-03-18T00:00:00Z

Background: Drug-eluting metallic coronary stents predispose to late stent thrombosis, prevent late lumen vessel enlargement, hinder surgical revascularisation, and impair imaging with multislice CT. We assessed the safety of the bioabsorbable everolimus-eluting stent (BVS). Methods: 30 patients with a single de-novo coronary artery lesion were followed up for 2 years clinically and with multiple imaging methods: multislice CT, angiography, intravascular ultrasound, derived morphology parameters (virtual histology, palpography, and echogenicity), and optical coherence tomography (OCT). Findings: Clinical data were obtained from 29 of 30 patients. At 2 years, the device was safe with no cardiac deaths, ischaemia-driven target lesion revascularisations, or stent thromboses recorded, and only one myocardial infarction (non-Q wave). 18-month multislice CT (assessed in 25 patients) showed a mean diameter stenosis of 19% (SD 9). At 2-year angiography, the in-stent late loss of 0·48 mm (SD 0·28) and the diameter stenosis of 27% (11) did not differ from the findings at 6 months. The luminal area enlargement on OCT and intravascular ultrasound between 6 months and 2 years was due to a decrease in plaque size without change in vessel size. At 2 years, 34·5% of strut locations presented no discernible features by OCT, confirming decreases in echogenicity and in radiofrequency backscattering; the remaining apparent struts were fully apposed. Additionally, vasomotion occurred at the stented site and adjacent coronary artery in response to vasoactive agents. Interpretation: At 2 years after implantation the stent was bioabsorbed, had vasomotion restored and restenosis prevented, and was clinically safe, suggesting freedom from late thrombosis. Late luminal enlargement due to plaque reduction without vessel remodelling needs confirmation. Funding: Abbott Vascular (USA).

A bioabsorbable everolimus-eluting coronary stent system for patients with single de-novo coronary artery lesions (ABSORB): a prospective open-label trial (Article)

2008-03-20T00:00:00Z

Background: A fully bioabsorbable drug-eluting coronary stent that scaffolds the vessel wall when needed and then disappears once the acute recoil and constrictive remodelling processes have subsided has theoretical advantages. The bioasorbable everolimus-eluting stent (BVS) has a backbone of poly-L-lactic acid that provides the support and a coating of poly-D,L-lactic acid that contains and controls the release of the antiproliferative agent everolimus. We assessed the feasibility and safety of this BVS stent. Methods: In this prospective, open-label study we enrolled 30 patients who had either stable, unstable, or silent ischaemia and a single de-novo lesion that was suitable for treatment with a single 3·0×12 mm or 3·0×18 mm stent. Patients were enrolled from four academic hospitals in Auckland, Rotterdam, Krakow, and Skejby. The composite endpoint was cardiac death, myocardial infarction, and ischaemia-driven target lesion revascularisation. Angiographic endpoints were available for 26 patients and intravascular-ultrasound endpoints for 24 patients. Clinical endpoints were assessed in all 30 patients at 6 and 12 months. In a subset of 13 patients, optical coherence tomography was undertaken at baseline and follow-up. Analysis was by intention to treat. This study is registered with ClinicalTrials.gov, number NCT00300131. Findings: Procedural success was 100% (30/30 patients), and device success 94% (29/31 attempts at implantation of the stent). At 1 year, the rate of major adverse cardiac events was 3·3%, with only one patient having a non-Q wave myocardial infarction and no target lesion revascularisations. No late stent thromboses were recorded. At 6-month follow-up, the angiographic in-stent late loss was 0·44 (0·35) mm and was mainly due to a mild reduction of the stent area (-11·8%) as measured by intravascular ultrasound. The neointimal area was small (0·30 [SD 0·44] mm2), with a minimal area obstruction of 5·5%. Interpretation: This study shows the feasibility of implantation of the bioabsorbable everolimus-eluting stent, with an acceptable in-stent late loss, minimal intrastent neointimal hyperplasia, and a low stent area obstruction. Funding: Abbott Vascular.

Actinomycin-eluting stent for coronary revascularization: a randomized feasibility and safety study: the ACTION trial. (Article)

2004-10-06T00:00:00Z

OBJECTIVES: We sought to demonstrate the safety and performance of the actinomycin D-coated Multilink-Tetra stent(Guidant Corp., Santa Clara, California) in the treatment of patients with single de novo native coronary lesions. BACKGROUND: Drug-eluting stents (DES) releasing sirolimus or paclitaxel dramatically reduce restenosis. The anti-proliferative drug, actinomycin D, which is highly effective in reducing neointimal proliferation in preclinical studies, was selected for clinical evaluation. METHODS: The multi-center, single-blind, three-arm ACTinomycin-eluting stent Improves Outcomes by reducing Neointimal hyperplasia (ACTION) trial randomized 360 patients to receive a DES (2.5 or 10 microg/cm(2) of actinomycin D) or metallic stent (MS). The primary end points were major adverse cardiac events (MACE) at 30 days, diameter stenosis by angiography, tissue effects, and neointimal volume by intravascular ultrasound (IVUS) at six months. When early monitoring revealed an increased rate of repeat revascularization, the protocol was amended to allow for additional follow-up for DES patients. Angiographic control of MS patients was no longer mandatory. RESULTS: The biased selection of DES patients undergoing IVUS follow-up invalidated the interpretation of the IVUS findings. The in-stent late lumen loss and that at the proximal and distal edges were higher in both DES groups than in the MS group and resulted in higher six-month and one-year MACE (34.8% and 43.1% vs. 13.5%), driven exclusively by target vessel revascularization without excess death or myocardial infarction. CONCLUSIONS: The results of the ACTION trial indicate that all anti-proliferative drugs will not uniformly show a drug class effect in the prevention of restenosis.

Chronic arterial responses to polymer-controlled paclitaxel-eluting stents: comparison with bare metal stents by serial intravascular ultrasound analyses: data from the randomized TAXUS-II trial. (Article)

2004-01-20T00:00:00Z

BACKGROUND: Polymer-controlled paclitaxel-eluting stents have shown a pronounced reduction in neointimal hyperplasia compared with bare metal stents (BMS). The aim of this substudy was to evaluate local arterial responses through the use of serial quantitative intravascular ultrasound (IVUS) analyses in the TAXUS II trial. 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 IVUS substudy included patients treated with one study stent who underwent serial IVUS examination after the procedure and at 6-month follow-up (BMS, 152 patients; SR, 81; MR, 81). The analyzed stented segment (15 mm) was divided into 5 subsegments in which mean vessel area (VA), stent area (SA), lumen area (LA), intrastent neointimal hyperplasia area (NIHA), and peristent area (VA-SA) were measured. NIHA was significantly reduced in SR (0.7+/-0.9 mm2, P<0.001) and MR (0.6+/-0.8 mm2, P<0.001) compared with BMS (1.9+/-1.5 mm2), with no differences between the two paclitaxel-eluting release formulations. Longitudinal distribution of neointimal hyperplasia throughout the paclitaxel-eluting stent was uniform. Neointimal growth was independent of peristent area at postprocedure examination in all groups. There were progressive increases in peristent area from BMS to SR to MR (0.5+/-1.7, 1.0+/-1.8, and 1.4+/-2.0 mm2, respectively; P<0.001). The increase in peristent area was directly correlated with increases in VA. CONCLUSIONS: Both SR and MR paclitaxel-eluting stents prevent neointimal formation to the same degree compared with BMS. However, the difference in peristent remodeling suggests a release-dependent effect between SR and MR.

Clinical and Angiographic Factors Associated With Asymptomatic Restenosis After Percutaneous Coronary Intervention (Article)

2001-01-01T00:00:00Z

BACKGROUND: Angiographic restenosis after percutaneous coronary interventional procedures is more common than recurrent angina. Clinical and angiographic factors associated with asymptomatic versus symptomatic restenosis after percutaneous coronary intervention were compared. METHODS AND RESULTS: All patients with angiographic restenosis from the BENESTENT I, BENESTENT II pilot, BENESTENT II, MUSIC, WEST 1, DUET, FINESS 2, FLARE, SOPHOS, and ROSE studies were analyzed. Multivariate analysis evaluated 46 clinical and angiographic variables, comparing those with and without angina. The 10 studies recruited 2690 patients who underwent percutaneous revascularization and 6-month follow-up angiography (86% of those eligible). Restenosis (>/=50% diameter stenosis) occurred in 607 patients and was clinically silent in 335 (55%). Male sex (P=0.008), absence of antianginal therapy with nitrates (P=0.0002) and calcium channel blockers (P=0.02) at 6 months, greater reference diameter after the procedure (P=0.04), greater reference diameter at follow-up (P=0.004), and lesser lesion severity (percent stenosis) at 6 months (P=0.0004) were univariate predictors of asymptomatic restenosis. By multivariate analysis, only male sex (P=0.04), greater reference diameter at follow-up (P=0.002), and lesser lesion severity at 6 months (P=0.0001) were associated with restenosis without angina. CONCLUSIONS: Approximately half of patients with angiographic restenosis have no symptoms. The only multivariate predictors of silent restenosis at 6 months were male sex, greater reference diameter at follow-up, and lesser lesion severity on follow-up angiography.

Does angiography six months after coronary intervention influence management and outcome? Benestent II Investigators. (Article)

1999-01-01T00:00:00Z

OBJECTIVES This study was performed to assess whether angiography six months after coronary balloon angioplasty or stent implantation has an influence on clinical management and one-year outcome. BACKGROUND The Benestent II study randomized 827 patients to balloon angioplasty or stent implantation. A subrandomization was undertaken allocating patients to six-month clinical follow-up (CF) or clinical and angiographic follow-up (AF). METHODS Seven hundred and six patients (349 CF and 357 AF) had no intercurrent angiography, so that restenosis and disease progression elsewhere remained unknown until the time of six-month follow-up. These two groups, which were well matched at enrolment, were compared with respect to symptoms, medication and major cardiac events defined as death, myocardial infarction and need for revascularization at six and 12 months. RESULTS At six-month follow-up, 53 (15%) of the CF and 76 (21%) of the AF patients had stable angina (p 5 0.041), while 5 (1%) and 4 (1%) had symptoms of unstable angina. At 12-month follow-up, 44 (13%) patients in both groups had stable angina, and only 1 patient in the CF group had unstable angina. Seventy-seven patients (27 CF and 50 AF; p , 0.01) had major cardiac events between 6 and 12 months. Of the 349 patients in the CF group, 21 underwent repeat percutaneous transluminal coronary angioplasty or coronary artery bypass graft surgery between 6 and 12 months, compared with 44 of the 357 patients in the AF group (relative risk 2.05 [1.24 to 3.37], p 5 0.003). CONCLUSIONS Patients who had AF six months after balloon angioplasty or stent implantation experienced more repeat revascularization procedures than those who had CF. They also had significantly more angina at six-month follow-up but this may be due to bias