Mid-term clinical outcomes of ABSORB bioresorbable vascular scaffold versus everolimus-eluting stent for coronary bifurcation lesions

The COBRA II (COmplex Bifurcation lesions: RAndomized comparison of a fully bioresorbable modified-T stenting strategy versus bifurcation reconstruction with a dedicated self-expanding stent in combination with bioresorbable scaffolds) study: Final 5-year follow-up

BACKGROUND

In order to advocate further research in bioresorbable scaffold (BVS) technology we report the final 5-year outcomes of the COBRA II study, the only randomized controlled trial (RCT) performed to investigate the safety, feasibility, and performance of Absorb BVS (Abbott Vascular) in true coronary bifurcations.

METHODS

COBRA II was a prospective single-center RCT. Fifteen patients with true coronary bifurcation lesions were randomized to bifurcation treatment with self-expanding biolimus-eluting Axxess bifurcation device (Biosensors International) combined with additional bioresorbable everolimus-eluting Absorb BVS in the bifurcation branches on (Axxess group) or to 2-stent mod-T stenting technique with Absorb BVS (mod-T group). Optical coherence tomography was performed post-procedure and at 30-months. The primary endpoint was change in minimal luminal area (MLA) on OCT from baseline to 30-months.

RESULTS

Fifteen patients with coronary bifurcation lesions were randomized to the Axxess group (n = 8) or Modified-T group (n = 7). At 30 months, MLAs were significantly smaller than post-procedure in the majority of bifurcation segments treated with BVS due to neointima formation, while MLAs in the proximal Axxess segment remained stable (primary endpoint). Five-year clinical follow-up was available for all patients. Only 1 major adverse cardiac event occurred; a patient underwent target lesion revascularization at 30 months in the Axxess group. There were no cases of cardiac death, spontaneous MI, or stent/scaffold thrombosis.

CONCLUSIONS

In this small RCT bifurcation study, BVS luminal dimensions were significantly smaller at 30 months, with acute strut discontinuities and late Intraluminal dismantling frequently observed, although acceptable clinical outcomes were noted at 5 years.

Histopathologic and physiologic effect of bifurcation stenting: current status and future prospects

Introduction: Coronary bifurcation lesions are involved in up to 20% of all percutaneous coronary interventions (PCI). However, bifurcation lesion intervention is associated with a high complication rate, and optimal treatment of coronary bifurcation is an ongoing debate.Areas covered: Both different stenting techniques and a variety of devices have been suggested for bifurcation treatment, including the use of conventional coronary stents, bioresorbable vascular scaffolds (BVS), drug-eluting balloons (DEB), and stents dedicated to bifurcations. This review will summarize different therapeutic approaches with their advantages and shortcomings, with special emphasis on histopathologic and physiologic effects of each treatment strategy.Expert opinion: Histopathology and clinical data have shown that a more simple treatment strategy is beneficial in bifurcation lesions, achieving superior results. Bifurcation interventions through balloon angioplasty or placement of stents can importantly alter the bifurcation's geometry and accordingly modify local flow conditions. Computational fluid dynamics (CFD) studies have shown that the outcome of bifurcation interventions is governed by local hemodynamic shear conditions. Minimizing detrimental flow conditions as much as possible should be the ultimate strategy to achieve long-term success of bifurcation interventions.

Multimodality intravascular imaging of bioresorbable vascular scaffolds implanted in vein grafts

Introduction

There are no data presenting a serial assessment of vein graft healing after bioresorbable vascular scaffold (BVS) implantation at long-term follow-up.

Aim

To describe ABSORB BVS healing in vein grafts by optical coherence tomography (OCT) and high-definition intravascular imaging (HD-IVUS) at long-term follow-up.

Material and methods: The study group consisted of 6 patients. The first patient had serial OCT assessment of BVS implanted in the saphenous vein grafts (SVG) at baseline and at 3-, 6-, 18-month follow-up and the second patient had OCT assessment of BVS implanted in the SVG at baseline and 24-, 48-month follow-up. The second and the third patients had OCT and HD-IVUS imaging at baseline and 48-month follow-up. The last 3 patients had OCT imaging of BVS implanted in the native coronary artery at 48-month follow-up.

Results

There were no differences in neointimal hyperplasia after BVS implantation between each time point. However, complete scaffold coverage was observed only 48 months after implantation. Out of 202 analyzed scaffold struts, there were 67 (33%) black boxes detectable at 48-month follow-up. HD-IVUS presented plaque burden up to 67% at the segment of BVS implantation at 48-months follow-up. There was a difference in neointimal hyperplasia thickness (1.27 (0.953–1.696) vs. 0.757 (0.633–0.848), p < 0.001) between a native coronary artery and BVS scaffolds at 48-month follow-up.

Conclusions

Bioresorbable vascular scaffold implanted in SVG characterized moderate neointimal hyperplasia as excessive as compared to native coronary arteries at long-term follow-up. The complete scaffold coverage was observed only 48 months after implantation.

Treatment strategies for coronary bifurcation lesions made easy in the current era by introduction of the BIFURCAID app

Coronary bifurcation lesions account for 15-20% of all percutaneous coronary interventions. Percutaneous revascularization of these lesions is technically challenging and results in lower success rates than nonbifurcation lesions. There are unique procedural considerations and techniques that are employed in the percutaneous revascularization of these lesions. Our objective is to define the procedural complexities of treating coronary bifurcation lesions and describe the leading provisional and dedicated two stent techniques used to optimize procedural and clinical results, as described in the BIFURCAID app.

Angiographic and Midterm Outcomes of Bioresorbable Vascular Scaffold for Coronary Bifurcation Lesions

Data on the angiographic and clinical performance of bioresorbable vascular scaffolds (BVS) for bifurcation lesions treatment are still limited. Data were examined of 107 patients with at least 1 coronary bifurcation lesion involving a side branch ≥2mm. Angiographic and clinical outcomes were collected. Optical coherence tomography analysis was performed in a subgroup of patients. Between July 2009 and December 2015, 423 patients underwent PCI with Absorb BVS. A total of 110 lesions were identified as bifurcations, of which 24.5% were classified as true bifurcation lesions. Lesion complexity B2/C was 68.1%. Ninety-five out of 110 lesions were treated by provisional stenting technique while 2 stenting strategy was the final approach in 15 lesions. Procedural success of main branch was 100% whereas side-branch impairment at the end of the procedure was 4.5%. The mean follow-up was 21 months with one-third of the patients followed up for at least 2 years. The overall target lesion failure and scaffold/stent thrombosis rate at 1 year was 7.8% and 3.9%, respectively. In conclusion the results of the present analysis suggest the BVS implanted in bifurcations lesions are associated with procedural safety and angiographic success as well as acceptable target lesion failure rate at 1 year.

Long-term follow-up of BVS from a prospective multicenter registry: Impact of a dedicated implantation technique on clinical outcomes

OBJECTIVES

The aim of this study was to evaluate the impact of a consistent and dedicated implantation strategy on long-term outcomes after implantation of bioresorbable vascular scaffold (BVS) in a real-world cohort of patients with a high prevalence of complex lesions.

BACKGROUND

Bioresorbable vascular scaffolds may result in a reduced incidence of late and very-late scaffold thrombosis (ScT) after the complete reabsorption of the scaffold, but this hypothesis is hampered by data from RCTs that showed a higher than expected incidence of late events. However, these studies did not adopt a dedicated implantation technique, that proved to be fundamental in reducing the incidence of adverse events.

METHODS

573 consecutive patients (912 lesions) treated with bioresorbable scaffolds between May 2012 and December 2014 were enrolled in 3 high-volume centers that used a dedicated implantation strategy from the beginning. Primary endpoints were target-lesion failure (TLF) and definite and probable ScT. Secondary endpoints included myocardial infarction, target-lesion and target-vessel revascularization.

RESULTS

The registry enrolled a high complexity subset of lesions (69.4% of type B2 or C lesions; 10.3% of severe calcific lesions; 26.1% of bifurcations). Predilatation was performed in almost all cases (99.2%); intracoronary imaging was liberally adopted (37.3%). Mean scaffold length was 42.9 ± 27.4 mm per patient, and post-dilation with a 1:1 high-pressure (22 ± 3.5 atm) balloon was performed in 99.9% of lesions. Median follow-up (available for 98.6% of patients) was 981 days (IQR 802-1133). Overall incidence of ScT was reassuringly low: three thrombotic events occurred during the first year (0.5%), while only one event ensued in the second year of follow-up, and ScT rate remained stable thereafter up to the fourth year (0.7%). Cumulative TLF rates at 1, 2, 3 and 4 years were 3.0%, 6.0%, 7.8% and 12.2%.

CONCLUSIONS

These long-term results from a complex "real-world" population appear to be reassuring as regards to the incidence of ScT and TLF when BVS are implanted by experienced operators with a dedicated implantation technique.