Incidence and imaging outcomes of acute scaffold disruption and late structural discontinuity after implantation of the absorb Everolimus-Eluting fully bioresorbable vascular scaffold: optical coherence tomography assessment in the ABSORB cohort B Trial (A Clinical Evaluation of the Bioabsorbable Everolimus Eluting Coronary Stent System in the Treatment of Patients With De Novo Native Coronary Artery Lesions).

OBJECTIVES: This study sought to describe the frequency and clinical impact of acute scaffold disruption and late strut discontinuity of the second-generation Absorb bioresorbable polymeric vascular scaffolds (Absorb BVS, Abbott Vascular, Santa Clara, California) in the ABSORB (A Clinical Evaluation of the Bioabsorbable Everolimus Eluting Coronary Stent System in the Treatment of Patients With De Novo Native Coronary Artery Lesions) cohort B study by optical coherence tomography (OCT) post-procedure and at 6, 12, 24, and 36 months. BACKGROUND: Fully bioresorbable scaffolds are a novel approach to treatment for coronary narrowing that provides transient vessel support with drug delivery capability without the long-term limitations of metallic drug-eluting stents. However, a potential drawback of the bioresorbable scaffold is the potential for disruption of the strut network when overexpanded. Conversely, the structural discontinuity of the polymeric struts at a late stage is a biologically programmed fate of the scaffold during the course of bioresorption. METHODS: The ABSORB cohort B trial is a multicenter single-arm trial assessing the safety and performance of the Absorb BVS in the treatment of 101 patients with de novo native coronary artery lesions. The current analysis included 51 patients with 143 OCT pullbacks who underwent OCT at baseline and follow-up. The presence of acute disruption or late discontinuities was diagnosed by the presence on OCT of stacked, overhung struts or isolated intraluminal struts disconnected from the expected circularity of the device. RESULTS: Of 51 patients with OCT imaging post-procedure, acute scaffold disruption was observed in 2 patients (3.9%), which could be related to overexpansion of the scaffold at the time of implantation. One patient had a target lesion revascularization that was presumably related to the disruption. Of 49 patients without acute disruption, late discontinuities were observed in 21 patients. There were no major adverse cardiac events associated with this finding except for 1 patient who had a non-ischemia-driven target lesion revascularization. CONCLUSIONS: Acute scaffold disruption is a rare iatrogenic phenomenon that has been anecdotally associated with anginal symptoms, whereas late strut discontinuity is observed in approximately 40% of patients and could be viewed as a serendipitous OCT finding of a normal bioresorption process without clinical implications. (ABSORB Clinical Investigation, Cohort B [ABSORB B]; NCT00856856).

The edge vascular response following implantation of the Absorb everolimus-eluting bioresorbable vascular scaffold and the XIENCE V metallic everolimus-eluting stent. First serial follow-up assessment at six months and two years: insights from the first-in-man ABSORB Cohort B and SPIRIT II trials.

AIMS: To assess serially the edge vascular response (EVR) of a bioresorbable vascular scaffold (BVS) compared to a metallic everolimus-eluting stent (EES). METHODS AND RESULTS: Non-serial evaluations of the Absorb BVS at one year have previously demonstrated proximal edge constrictive remodelling and distal edge changes in plaque composition with increase of the percent fibro-fatty (FF) tissue component. The 5 mm proximal and distal segments adjacent to the implanted devices were investigated serially with intravascular ultrasound (IVUS), post procedure, at six months and at two years, from the ABSORB Cohort B1 (n=45) and the SPIRIT II (n=113) trials. Twenty-two proximal and twenty-four distal edge segments were available for analysis in the ABSORB Cohort B1 trial. In the SPIRIT II trial, thirty-three proximal and forty-six distal edge segments were analysed. At the 5-mm proximal edge, the vessels treated with an Absorb BVS from post procedure to two years demonstrated a lumen loss (LL) of 6.68% (-17.33; 2.08) (p=0.027) with a trend toward plaque area increase of 7.55% (-4.68; 27.11) (p=0.06). At the 5-mm distal edge no major changes were evident at either time point. At the 5-mm proximal edge the vessels treated with a XIENCE V EES from post procedure to two years did not show any signs of LL, only plaque area decrease of 6.90% (-17.86; 4.23) (p=0.035). At the distal edge no major changes were evident with regard to either lumen area or vessel remodelling at the same time point. CONCLUSIONS: The IVUS-based serial evaluation of the EVR up to two years following implantation of a bioresorbable everolimus-eluting scaffold shows a statistically significant proximal edge LL; however, this finding did not seem to have any clinical implications in the serial assessment. The upcoming imaging follow-up of the Absorb BVS at three years is anticipated to provide further information regarding the vessel wall behaviour at the edges.

First serial assessment at 6 months and 2 years of the second generation of absorb everolimus-eluting bioresorbable vascular scaffold: a multi-imaging modality study.

BACKGROUND: Nonserial observations have shown this bioresorbable scaffold to have no signs of area reduction at 6 months and recovery of vasomotion at 1 year. Serial observations at 6 months and 2 years have to confirm the absence of late restenosis or unfavorable imaging outcomes. METHODS AND RESULTS: The ABSORB trial is a multicenter single-arm trial assessing the safety and performance of an everolimus-eluting bioresorbable vascular scaffold. Forty-five patients underwent serial invasive imaging, such as quantitative coronary angiography, intravascular ultrasound, and optical coherence tomography at 6 and 24 months of follow-up. From 6 to 24 months, late luminal loss increased from 0.16±0.18 to 0.27±0.20 mm on quantitative coronary angiography, with an increase in neointima of 0.68±0.43 mm(2) on optical coherence tomography and 0.17±0.26 mm(2) on intravascular ultrasound. Struts still recognizable on optical coherence tomography at 2 years showed 99% of neointimal coverage with optical and ultrasonic signs of bioresorption accompanied by increase in mean scaffold area compared with baseline (0.54±1.09 mm(2) on intravascular ultrasound, P=0.003 and 0.77±1.33 m(2) on optical coherence tomography, P=0.016). Two-year major adverse cardiac event rate was 6.8% without any scaffold thrombosis. CONCLUSIONS: This serial analysis of the second generation of the everolimus-eluting bioresorbable vascular scaffold confirmed, at medium term, the safety and efficacy of the new device. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT00856856.

A comparative assessment by optical coherence tomography of the performance of the first and second generation of the everolimus-eluting bioresorbable vascular scaffolds.

AIMS: The first generation of the everolimus-eluting bioresorbable vascular scaffold (BVS 1.0) showed an angiographic late loss higher than the metallic everolimus-eluting stent Xience V due to scaffold shrinkage. The new generation (BVS 1.1) presents a different design and manufacturing process than the BVS 1.0. This study sought to evaluate the differences in late shrinkage, neointimal response, and bioresorption process between these two scaffold generations using optical coherence tomography (OCT). METHODS AND RESULTS: A total of 12 lesions treated with the BVS 1.0 and 12 selected lesions treated with the revised BVS 1.1 were imaged at baseline and 6-month follow-up with OCT. Late shrinkage and neointimal area (NIA) were derived from OCT area measurements. Neointimal thickness was measured in each strut. Strut appearance has been classified as previously described. Baseline clinical, angiographic, and OCT characteristics were mainly similar in the two groups. At 6 months, absolute and relative shrinkages were significantly larger for the BVS 1.0 than for the BVS 1.1 (0.98 vs. 0.07 mm² and 13.0 vs. 1.0%, respectively; P = 0.01). Neointimal area was significantly higher in the BVS 1.0 than in the BVS 1.1 (in-scaffold area obstruction of 23.6 vs. 12.3%; P < 0.01). Neointimal thickness was also larger in the BVS 1.0 than in the BVS 1.1 (166.0 vs. 76.4 µm; P < 0.01). Consequently, OCT, intravascular ultrasound, and angiographic luminal losses were higher with the BVS 1.0 than with the BVS 1.1. At 6 months, strut appearance was preserved in only 2.9% of the BVS 1.0 struts, but remained unchanged with the BVS 1.1 indicating different state of strut microstucture and/or their reflectivity. CONCLUSION: The BVS 1.1 has less late shrinkage and less neointimal growth at 6-month follow-up compared with the BVS 1.0. A difference in polymer degradation leading to changes in microstructure and reflectivity is the most plausible explanation for this finding.

Effectiveness of "direct" stenting without balloon predilatation (from the Multilink Tetra Randomised European Direct Stent Study [TRENDS]).

The purpose of the TRENDS trial was to assess the safety, efficacy, and cost effectiveness of a no-predilatation ("direct") stenting strategy in the treatment of de novo native coronary artery lesions using the Multilink Tetra stent system. In this multicenter, prospective clinical trial, 1,000 patients were randomized (1:1) to receive a Multilink Tetra stent with or without balloon predilatation. The primary outcome measurement was major adverse cardiac events (MACEs) at 30 days; secondary end points included resource utilization (including procedural duration, equipment use, and length of hospital stay), MACEs, and angiographic binary restenosis at 180 days. In the predilatation group, 587 stents were implanted in 499 patients; in the direct group, 579 stents were implanted in 501 patients. In the direct group, stents in 31 lesions (5.7%) required predilatation and multivariate analysis identified calcification (odds ratio 5.81), angulation (odds ratio 5.34), and preprocedural minimal lumen diameter (odds ratio 0.09) as direct stenting failure. MACEs at 30 days were similar in the 2 groups, with 19 (3.8%) in the predilatation group and 13 (2.6%) in the direct group (p = NS). Resource utilization favored the direct strategy, with decreases in balloon use, contrast media, and procedure time, but a larger number of guiding catheters was used. The 180-day MACE rate of 9.8% in the direct group was not significantly less than the rate of 10.8% in the predilatation group (p = NS). Quantitative angiographic follow-up at 6 months demonstrated in-stent binary restenotic rates of 11.4% in the predilatation group (late loss 0.88 +/- 0.53 mm) and 12.3% in the direct group (late loss 0.82 +/- 0.51 mm, p = NS) and in-segment restenosis rates of 12.2% and 13.4%, respectively (p = NS). In conclusion, a direct stenting strategy with the Multilink Tetra stent was feasible and safe in 94% of lesions and associated with lower resource utilization compared with a predilatation approach. Direct stenting was not associated with significantly lower MACE and target lesion revascularization rates and had no effect on late angiographic follow-up, with similar late loss reflecting an identical biologic response to bare metal stent placement.

The Frontier stent registry: safety and feasibility of a novel dedicated stent for the treatment of bifurcation coronary artery lesions.

OBJECTIVES: The goal of this study was to evaluate the safety and performance of the Multi-Link Frontier coronary bifurcation stent system (Guidant Corp., Santa Clara, California), a novel dedicated device designed for permanent side branch (SB) access, stent delivery by simultaneous kissing balloon inflation, and optimal main branch (MB) and SB ostium scaffolding. BACKGROUND: The treatment of coronary bifurcation lesions remains challenging, and various approaches using stents have been proposed. METHODS: The primary end point was the 180-day incidence of major adverse cardiac events (MACE) per intent-to-treat analysis. Secondary end points included device success, 30-day MACE, angiographic restenosis, and target lesion revascularization (TLR) rates at 180 days. RESULTS: After a learning phase of two cases per center, 105 patients were prospectively included in 11 centers. The left anterior descending coronary artery/diagonal bifurcation was the target in 80% of cases. The Frontier stent was successfully implanted in 96 patients (91%), and procedural success was obtained in 93%. Two patients suffered in-hospital myocardial infarction (MI) secondary to SB occlusion, and one patient underwent elective coronary artery bypass grafting. At 30 days and 6 months, the MACE rates were 2.9% and 17.1% (no death, no subacute stent thrombosis, Q-wave MI 1.0% and 1.9%, non-Q-wave MI 1.0% and 1.9%, TLR 1.0% and 13.3%). The MB in-stent restenosis was 25.3%, in-segment 29.9%. The SB restenosis was 29.1%. The overall restenosis rate for any branch was 44.8%. CONCLUSIONS: The results of this Frontier registry demonstrate the safety and performance of this dedicated stent system for the treatment of bifurcation lesions. The device can be successfully implanted in more than 90% of all cases, with a high procedural success rate and low 30-day and 6-month MACE rates.