Anatomical features and management of bioresorbable vascular scaffolds failure: A case series from the GHOST registry

Procedural Results and One-Year Clinical Outcomes of Treatment of Bioresorbable Vascular Scaffolds Restenosis (from the RIBS VII Prospective Study)

Currently, both drug-eluting stents (DES) and drug-eluting balloons are recommended in patients with in-stent restenosis (ISR) of metallic stents. However, the clinical results of repeated interventions in patients with restenosis of bioresorbable vascular scaffolds (BVS) remain unsettled. We sought to assess the results of interventions in patients with BVS-ISR as compared with those obtained in patients with ISR of DES and bare-metal stents (BMS). Restenosis Intrastent: Treatment of Bioresorbable Vascular Scaffolds Restenosis (RIBS VII) is a prospective multicenter study (23 Spanish sites) that included 117 consecutive patients treated for BVS-ISR. Inclusion/exclusion criteria were similar to those of previous RIBS studies. Patients in the RIBS IV (DES-ISR, n = 309) and RIBS V (BMS - ISR, n = 189) randomized trials, were used as controls. Most patients with BVS-ISR were treated with DES (76%). Patients with BVS-ISR were younger, had larger vessels, and after interventions had higher in-segment residual diameter stenosis (19 ± 13%, 15 ± 11%, 15 ± 12%, p <0.001) than those treated for DES-ISR and BMS-ISR, respectively. At 1-year clinical follow-up (obtained in 100% of patients) target lesion revascularization (6%) was similar to that seen in patients with DES-ISR and BMS-ISR (8.7% and 3.7%, p = 0.32). Freedom from death, myocardial infarction, and target vessel revascularization (primary clinical end point) was 8.5%, also similar to that found in patients with DES-ISR and BMS-ISR (14.2% and 7.4%, p = 0.09). Results were also similar when only patients treated with DES in each group were compared and remained unchanged after adjusting for potential confounders in baseline characteristics. Time to BVS-ISR did not influence angiographic or clinical results. This study demonstrates the safety and efficacy of coronary interventions for patients presenting with BVS-ISR. One-year clinical results in these patients are comparable to those seen in patients with ISR of metallic stents (ClinicalTrials.gov ID:NCT03167424).

Major adverse cardiovascular events after implantation of absorb bioresorbable scaffold: One-year clinical outcomes

Background/Aim: Bioresorbable vascular scaffold (BVS) represents a novel generation of intracoronary devices designed to be fully resorbed after healing of the stented lesion, delivering antiproliferative drug to suppress restenosis, providing adequate diameter of the coronary vessel and preserving the vascular endothelial function. It was supposed that BVS will reduce neointimal proliferation and that their late bioresorption will reduce the negative effects of traditional drug-eluting stents, including the late stent thrombosis, local vessel wall inflammation, loss of coronary vasoreactivity and the need for the long-term dual antiplatelet therapy. The purpose of this research was to investigate efficacy and safety of Absorb everolimus-eluting BVS implantation and the prevalence of major adverse cardiovascular events (MACE) at the mid-term follow-up. Methods: The study encompassed 42 patients selected for BVS implantation and fulfilling inclusion criteria - 37 male and 5 female - admitted to the Dedinje Cardiovascular Institute, Belgrade, Serbia over the one-year period (from January 2015 to January 2016) for percutaneous coronary intervention (PCI). Coronary vessel patency before and after stenting was assessed by the Thrombolysis in Myocardial Infarction flow (TIMI) grades. After the index PCI procedure with BVS all patients were clinically followed by regular (prescheduled or event-driven) visits during the next 12-month period. Results: In the intention-to-treat analysis, all Absorb BVS procedures were successful, without the need for conversion to other treatment modalities. The complete reperfusion (TIMI flow grade 3) after the intervention was established in 97.6 % of patients and 100 % of them achieved the TIMI flow grade ≥ 2. The presence of angina pectoris was reduced significantly by the BVS procedure: stable angina 57.1 % to 11.9 %, (p < 0.001) and unstable angina 31 % to 0 %, respectively (p < 0.001). After the one-year follow-up, the MACE rate was 11.9 %. Myocardial infarction occurred in 4.8 % and the need for PCI reintervention in 2.4 % of cases (not influenced by the gender or the age of patients). There were 4 cases of death (all patients were older and had lower values of left ventricular ejection fraction). Conclusion: The results of the current research demonstrated a high interventional success rate of the Absorb BVS implantation, followed by the early improvement of the anginal status. However, that was not translated into the favourable mid-term clinical outcomes, opening debate about the current status of Absorb BVS and the need for future refinements of stent design and implantation techniques.

The impact of the use of bioresorbable vascular scaffolds and drug-coated balloons in coronary bifurcation lesions

BACKGROUND

Despite the improvement in techniques and tools, coronary lesions involving a bifurcation are still challenging and the outcome with drug-eluting stents is not always optimal. The role of bioresorbable vascular scaffolds (BVS) and drug-coated balloons (DCB) in this setting has not been adequately investigated yet.

RESULTS

From the databases of 6 italian centers with high proficiencies in newer technologies, we retrospectively collected all consecutive cases of coronary bifurcations managed or attempted with the implantation of at least one BVS in the main vessel and the use of one DCB in the side branch (SB). Primary study endpoint was the occurrence of major adverse cardiovascular events (MACE) at the longest available follow-up. Fourty patients fulfilled the enrollment criterion, 22.5% had diabetes and 50% an acute coronary syndrome. Average syntax score was 15.04 ± 7.18, all lesions were de novo, and 27 patients (67.5%) had a type 1,1,1 Medina lesion. Twenty-three lesions (57.5%) involved the proximal left anterior-descending artery/first diagonal branch. Only 32.5% of patients underwent an intravascular imaging-guided angioplasty. Average lesion length was 21.4 mm in the main vessel and 11.49 mm in the SB. MV was always predilated and BVS received a postdilation in 100% of the cases. In 42.5% of the cases, the DCB was used during final kissing balloon inflation, and in no cases, a stent/BVS was required in the SB. Procedural success was achieved in 100% of the cases. After an average follow-up of 15.5 (± 11.5) months, we observed no MACE with only one case of target vessel revasularization (2.5%).

CONCLUSIONS

Management of coronary bifurcation lesions with the use of newer technologies including BVS and DCB seems feasible and effective at mid-term and long-term clinical follow-up.

Impact of calcium on procedural and clinical outcomes in lesions treated with bioresorbable vascular scaffolds - A prospective BRS registry study

BACKGROUND

There is limited data on the impact of calcium (Ca) on acute procedural and clinical outcomes in patients with lesions treated with bioresorbable vascular scaffolds (BRS). We sought to evaluate the effect of calcium on procedural and clinical outcomes in a 'real world' population.

METHODS

Clinical outcomes were compared between patients with at least 1 moderately or heavily calcified lesion (Ca) and patients with no/mild calcified lesions (non-Ca) enrolled in our institutional BRS registry.

RESULTS

455 patients (N) with 548 lesions (L) treated with 735 BRS were studied. Patients in the Ca group (N=160, L=200) had more complex (AHA B2/C lesion: 69.0% in Ca vs 14.9% in non-Ca, p<0.001) and significantly longer lesions (27.80±15.27 vs 19.48±9.92mm, p<0.001). Overall device success rate was 99.1% with no significant differences between the groups. Despite more aggressive lesion preparation and postdilation compared to non Ca, acute lumen gain was significantly less in Ca lesions (1.50±0.66 vs 1.62±0.69mm, p=0.040) with lower final MLD (2.28±0.41 vs 2.36±0.43, p=0.046). There were no significant differences in all-cause mortality, total definite scaffold thrombosis (ST), target lesion revascularization and myocardial infarction between the 2 groups. Late ST was more frequent in the Ca group compared to non Ca group (late ST: 2.1 vs 0%, p=0.02).

CONCLUSIONS

Clinical outcomes after BRS implantation in calcified and non-calcified lesions were similar. A remarkable difference in timing of thrombosis was observed, with an increased rate of late thrombosis in calcified lesions.

Occurrence and management of bioresorbable vascular scaffold failure in real-life studies

Bioresorbable vascular scaffold (BVS) has emerged as a new technology aiming at overcoming some drawbacks of the conventional metallic stent. In spite of the initial promising results, this technology stumbled upon numerous challenges, which were revealed in the real world studies. Thanks to real world trials and registries findings, our knowledge about the BVS has grown over time, thus we have understood on BVS behavior in various settings and formulated better implantation techniques. In this article, we will review the incidence of BVS failure in real world studies, its different etiologies and management strategies.

Long-term in vivo corrosion behavior, biocompatibility and bioresorption mechanism of a bioresorbable nitrided iron scaffold

Pure iron as a potential bioresorbable material for bioresorbable coronary scaffold has major disadvantages of slow corrosion and bioresorption. However, so far, there are neither quantitative data of long-term in vivo corrosion nor direct experimental evidence for bioresorption of pure iron and its alloys, which are fundamental and vital for developing novel Fe-based alloys overcoming the intrinsic drawbacks of pure iron. This work systemically investigated scaffold performance, long-term in vivo corrosion behavior and biocompatibility of a nitrided iron coronary scaffold and explored its bioresorption mechanism. It was found that the 70μm Fe-based scaffold was superior to a state of the art Co-Cr alloy stent (Xience Prime™) in terms of crossing profile, recoil and radial strength. Mass loss was 76.0±8.5wt% for the nitrided iron scaffold and 44.2±11.4wt% for the pure iron scaffold after 36months implantation in rabbit abdominal aorta (p<0.05). The Fe-based scaffold showed good long-term biocompatibility in both rabbit and porcine model. Its insoluble corrosion products were demonstrated biosafe and could be cleared away by macrophages from in situ to adventitia to be indiscernible by Micro Computed Tomography and probably finally enter the lymphatics and travel to lymph nodes after 53months implantion in porcine coronary artery. The results indicate that the nitrided iron scaffold with further improvements shall be promising for coronary application.

STATEMENT OF SIGNIFICANCE

Pure iron as a potential bioresorbable material has major disadvantages of slow corrosion and bioresorption. However, so far, there are neither quantitative data of long-term in vivo corrosion nor direct experimental evidence for bioresorption of pure iron and its alloys. Only this work systemically investigated long-term in vivo corrosion behavior and biocompatibility of a nitrided iron coronary scaffold up to 53months after implantation and explored its bioresorption mechanism. These are fundamental and vital for developing novel Fe-based alloys overcoming the intrinsic drawbacks of pure iron. Novel testing and section-preparing methods were also provided in this work to facilitate future research and development of novel Fe-based alloy scaffolds.

Restenosis After Everolimus-eluting Vascular Scaffolding. Angiographic and Optical Coherence Tomography Characterization

INTRODUCTION AND OBJECTIVES

Coronary restenosis after bioresorbable vascular scaffold (BVS) implantation is infrequent and little information is available on the main characteristics of these lesions. The aim of this study was to assess restenotic lesions by using optical coherence tomography (OCT).

METHODS

We studied 330 patients with coronary artery disease who received 398 BVS to treat 380 lesions. These patients were clinically and angiographically evaluated at follow-up and OCT was carried out on detection of restenosis.

RESULTS

After a follow-up of 19 ± 10 months, 18 restenotic lesions were detected in 17 patients (5.4%). Depending on the time of presentation, most cases of restenosis were late or very late (9 ± 4 months). The most frequent angiographic pattern was focal restenosis in 12 (67%) patients, which was mainly located at the proximal border in 9 (75%) whether involving the scaffold or not. The homogeneous pattern was infrequent, occurring in 3 (25%) lesions and was only visualized in 3 out of 6 cases of restenosis located at the margin. When the focal restenosis was located in the platform, OCT showed a heterogeneous or layered pattern. Finally, diffuse restenosis was observed in 6 patients (33%). In diffuse restenosis, OCT revealed a lipid-laden or layered tissue structure and the presence of microvessels or microcalcification, potentially suggesting a neoatherosclerotic process.

CONCLUSIONS

After a mean follow-up of 19 months, the restenosis rate was 5.4%. Most restenotic lesions were focal, located at the proximal border. Diffuse restenosis mostly occurred late or very late and most showed signs suggestive of neoatherosclerosis.

Long-Term Clinical Outcomes After Bioresorbable Vascular Scaffold Implantation for the Treatment of Coronary In-Stent Restenosis: A Multicenter Italian Experience

BACKGROUND

Treatment of in-stent restenosis (ISR) is still challenging. In this setting, the use of bioresorbable vascular scaffold (BVS) seems attractive because it allows drug delivery combined with transient vessel scaffolding. We aimed to investigate the long-term results after BVS use in ISR lesions.

METHODS AND RESULTS

A prospective analysis was performed on all patients who underwent percutaneous coronary intervention with BVS implantation for ISR at 7 Italian Centers. Primary end point was the device-oriented composite end point (cardiac death, target vessel myocardial infarction, and ischemia-driven target lesion revascularization) at the longest follow-up available. From April 2012 to June 2014, 116 patients (127 lesions) underwent percutaneous coronary intervention for ISR with BVS implantation. Among the ISR lesions, the majority were drug-eluting stent ISR (78, 61.6%), de novo ISR (92, 72.4%), and diffuse ISR (81, 63.8%). Procedural success was achieved for all (100%) patients. No in-hospital death, myocardial infarction, or revascularization occurred. At 15 months of follow-up, the incidence of the device-oriented composite end point estimated with the Kaplan-Meier method was 9.1%. No significant differences were reported between drug-eluting stent and bare-metal stent ISR groups in terms of device-oriented composite end point (10.9% versus 6.4%; hazard ratio, 1.7; 95% confidence interval, 0.5-6.5; P=0.425) and its singular components (cardiac death: 2.8% versus 2.0%, hazard ratio, 1.3; 95% confidence interval, 0.1-14.1, P=0.843; target vessel myocardial infarction: 1.5% versus 0%, P=0.421; ischemia-driven target lesion revascularization: 9.6% versus 4.4%, hazard ratio, 2.3; 95% confidence interval, 0.5-10.8, P=0.309).

CONCLUSIONS

Our registry suggests that the use of BVS implantation for the treatment of complex drug-eluting stent and bare-metal stent ISR lesions might be associated with acceptable long-term clinical outcomes.

Role of invasive imaging in acute and long-term assessment of bioresorbable scaffold technology

Fully bioresorbable scaffolds (BRS) represent a novel approach for the percutaneous treatment of coronary artery stenosis, providing temporary vessel scaffolding with drug-eluting capability during the restenosis-prone phase of the vascular healing. Beyond this initial critical period, when mechanical scaffolding support is no longer necessary, the device is bioresorbed, restoring the normal vascular physiology with the aim to eliminate the long-term safety concerns related to permanent metallic implants. Nonetheless, current BRS technology suffers from limited mechanical properties as compared to available metallic platforms, requiring careful attention to lesion preparation, accurate vessel sizing, and implantation technique. Intravascular imaging has played an important role in providing knowledge on the acute effects after BRS deployment, and it helped refine the current technique of BRS implantation. In addition, extensive work with multiple intravascular imaging modalities have also contributed to the understanding of the unique dynamic vascular changes that are experienced in the treated segment from post-implantation up to complete device bioresorption. In this manuscript, we review the role of invasive imaging modalities-from angiography to sound- and light-based techniques-to guide BRS implantation procedures, to assess its acute results postimplantation, and the changes experienced in the long-term until complete bioresorption has ensued. © 2016 Wiley Periodicals, Inc.

Prevalence of parameters of suboptimal scaffold deployment following angiographic guided bioresorbable vascular scaffold implantation in real world practice - an optical coherence tomography analysis

AIM

To assess the prevalence of suboptimal bioresorbable vascular scaffold (BVS, Abbott Vascular, Santa Clara, California) deployment in real world practice with intracoronary optical coherence tomography (OCT) imaging.

METHODS

Consecutive patients who underwent percutaneous coronary intervention using BVS and the final optimization assessed with OCT imaging in two tertiary care centers between December 2012 and February 2015 were evaluated for parameters of suboptimal scaffold deployment by OCT.

RESULTS

Overall, 36 scaffolds were implanted in 27 patients during this period. Mean age of the population was 54.7±8.2years and 19 (70.4%) were type B2/C lesions. The prevalence of parameters of suboptimal scaffold deployment were: underexpansion-22(61.1%), geographic miss-3(8.3%), tissue prolapse-7(25.9%), scaffold pattern irregularity-1(2.8%), longitudinal elongation-7(38.8%). Of the 7 overlaps imaged: excessive overlap was observed in 3 and scaffold gap in one. The median duration of follow up was 679days (range 193-963days). There were four events during this period. None were associated with suboptimal scaffold deployment.

CONCLUSION

OCT based parameters of suboptimal scaffold deployment are common in real world scenario and were not associated with adverse outcomes on long term follow up. These findings need to be confirmed in larger studies.