Optical coherence tomography guidance for percutaneous coronary intervention with bioresorbable scaffolds

Systematic Review and Meta-Analysis of the Super High-Pressure Balloon (SIS-OPN) for Percutaneous Coronary Intervention

INTRODUCTION

The super high-pressure NC balloon (OPN NC; SIS Medical AG, Winterthur, Switzerland) is increasingly used in percutaneous coronary intervention (PCI). We performed a systematic review and meta-analysis of its efficacy and safety.

METHODS

A systematic review was conducted using PubMed and the Cochrane Library to identify studies using the OPN NC balloon in PCI. Procedural success, major adverse cardiac events (MACE), coronary perforation, and other complications were pooled using weighted means, confidence intervals (CI), and I² statistics for heterogeneity assessment.

RESULTS

Twenty-nine studies (5 prospective including 2 randomized-controlled trials, 12 retrospective, and 12 case reports) were included in the systematic review, of which 11 (3 prospective, 8 retrospective) were included in the meta-analysis. Of the 1015 meta-analysis patients, 50.7% presented with stable angina and 21.6% with an acute coronary syndrome. Mean lesion length was 22.8 ± 13.7 mm, the prevalence of moderate or severe calcification was 93.7%, and 40.4% of lesions were in-stent. Procedural success was 95.1% (95% CI 89.3%-98.8% with significant heterogeneity: I² = 84.9%). The incidence of periprocedural MACE was 1.9% (95% CI 1.1%-2.8%, I² 86.9%), and the incidence of coronary perforation was 0.6% (95% CI 0.3%-1.5%, I² 87.2%).

CONCLUSIONS

Use of the OPN NC balloon is associated with high success and acceptable complication rates. The heterogeneity of outcomes underscores the need for additional studies and standardized definitions.

Recurrent drug eluting stent, in-stent restenosis (DES-ISR): Epidemiology, pathophysiology & treatment

Coronary artery in-stent restenosis (ISR) is driven by neointimal hyperplasia and neo-atherosclerosis in previously placed stents. Drug eluting stents (DES) have been adopted as first line therapy for the initial episode of ISR. However, recurrent ISR has limited durable salvage options. In this article we review the pathophysiology, incidence, and management options of recurrent DES- ISR.

Current Role of Intracoronary Imaging for Implementing Risk Stratification and Tailoring Culprit Lesion Treatment: A Narrative Review

Our understanding of the pathophysiology of acute coronary syndrome and of the vascular biology of coronary atherosclerosis has made enormous progress with the implementation of intravascular imaging. Intravascular imaging contributes to overcoming the known limitations of coronary angiography and allows for the in vivo discrimination of plaque morphology giving insight into the underlying pathology of the disease process. The possibility of using intracoronary imaging to characterize lesion morphologies and correlate them with clinical presentations may influence the treatment of patients and improve risk stratification, offering the opportunity for tailored management. This review examines the current role of intravascular imaging and describes how intracoronary imaging represents a valuable tool for modern interventional cardiology in order to improve diagnostic accuracy and offer a tailored approach to the treatment of patients with coronary artery disease, especially in the acute setting.

Bioresorbable Scaffolds: Contemporary Status and Future Directions

Percutaneous coronary intervention, which is safe, effective, and timely, has become an important treatment for coronary artery diseases and has been widely used in clinical practice. However, there are still some problems that urgently need to be solved. Permanent vessel caging through metallic implants not only prevents the process of positive vessel remodeling and the restoration of vascular physiology but also makes the future revascularization of target vessels more difficult. Bioresorbable scaffolds (BRSs) have been developed as a potential solution to avoid the above adverse reactions caused by permanent metallic devices. BRSs provide temporary support to the vessel wall in the short term and then gradually degrade over time to restore the natural state of coronary arteries. Nonetheless, long-term follow-up of large-scale trials has drawn considerable attention to the safety of BRSs, and the significantly increased risk of late scaffold thrombosis (ScT) limits its clinical application. In this review, we summarize the current status and clinical experiences of BRSs to understand the application prospects and limitations of these devices. In addition, we focus on ScT after implantation, as it is currently the primary drawback of BRS. We also analyze the causes of ScT and discuss improvements required to overcome this serious drawback and to move the field forward.

Sirolimus-Eluting Balloon for the Treatment of Coronary Lesions in Complex ACS Patients: The SELFIE Registry

BACKGROUND

Sirolimus-coated balloons (SCBs) represent a novel therapeutic option for both in-stent restenosis (ISR) and de novo coronary lesions treatment, especially in small vessels. Our registry sought to evaluate the procedural and clinical outcomes of such devices in a complex acute coronary syndrome (ACS) clinical setting.

METHODS AND RESULTS

We treated 74 consecutive patients with percutaneous coronary intervention (PCI) with at least 1 SCB used for ISR and/or de novo coronary lesion in small vessels at our institution. Sixty-two patients presented with ACS, and their data were included in our analysis. The mean age was 67 ± 10 years, and patients presenting with ST-elevated myocardial infarction (STEMI) were 14 (23%). De novo lesions were 52%, whereas ISR was 48%. Procedural success occurred in 100% of the cases. At the 11 ± 7 months follow-up, major adverse cardiovascular events (MACEs) were 3 (4.8%). Cardiovascular death (CD) occurred in 1 (1.6%) patient and myocardial infarction (MI) in 2 patients (3.2%) as well as ischemia-driven target lesion revascularization (TLR). One probable subacute thrombosis occurred (1.6%) with no major bleedings. In a subgroup analysis, the incidence of MACE did not show significant differences between patients treated for de novo lesions and ISR (HR: 0.239; CI 95%: 0.003-16.761, p=0.509).

CONCLUSIONS

In the SELFIE prospective registry, SCB showed a good safety and efficacy profile for the treatment of coronary lesions, both ISR and/or de novo in small vessels, in a complex ACS population of patients at the 11 ± 7 months follow-up.

Optical Coherence Tomography for Coronary Bioresorbable Vascular Scaffold Implantation: A Randomized Controlled Trial

BACKGROUND

We investigated whether optical coherence tomography (OCT) guidance would reduce nonoptimal bioresorbable vascular scaffold (BVS) deployment.

METHODS

This was a randomized controlled trial. Patients who required percutaneous coronary intervention for ischemic heart disease were recruited from 2 centers in Korea. The enrolled patients were randomly assigned to receive either OCT-guided BVS (Absorb; Abbott Vascular) implantation or angiography-guided BVS implantation using an optimized technique. The primary outcome was nonoptimal deployment, which was a composite outcome of the following parameters assessed by OCT: a minimal scaffold area <5 mm², residual area stenosis >20%, incomplete apposition of the scaffold struts >5%, major edge dissection, or scaffold disruption. The secondary outcome was a procedural complication defined by the occurrence of no reflow, coronary perforation, or flow-limiting dissection.

RESULTS

Between September 2016 and January 2018, 88 patients (90 lesions) were assigned to OCT guidance, while 88 patients (89 lesions) were assigned to angiography guidance. The recruitment was prematurely terminated in March 2018 because the manufacturer stopped supplying BVS. Postprocedural OCT data were available for 88 lesions with OCT guidance and for 88 lesions with angiography guidance. There was nonoptimal BVS deployment postprocedurally in 35.2% of patients in the OCT-guidance group and in 38.6% in the angiography-guidance group (absolute difference, -3.7% [95% CI, -19.0% to 11.6%]; P=0.64). There were no procedural complications in either group.

CONCLUSIONS

OCT-guided BVS implantation did not reduce the incidence of nonoptimal deployment compared to that of angiography-guided BVS implantation (using optimized techniques).

CLINICAL TRIAL REGISTRATION

URL: https://www.clinicaltrials.gov. Unique identifier: NCT02894697.

Bioresorbable Vascular Scaffolds-Dead End or Still a Rough Diamond?

Percutaneous coronary interventions with stent-based restorations of vessel patency have become the gold standard in the treatment of acute coronary states. Bioresorbable vascular scaffolds (BVS) have been designed to combine the efficiency of drug-eluting stents (DES) at the time of implantation and the advantages of a lack of foreign body afterwards. Complete resolution of the scaffold was intended to enable the restoration of vasomotor function and reduce the risk of device thrombosis. While early reports demonstrated superiority of BVS over DES, larger-scale application and longer observation exposed major concerns about their use, including lower radial strength and higher risk of thrombosis resulting in higher rate of major adverse cardiac events. Further focus on procedural details and research on the second generation of BVS with novel properties did not allow to unequivocally challenge position of DES. Nevertheless, BVS still have a chance to present superiority in distinctive indications. This review presents an outlook on the available first and second generation BVS and a summary of results of clinical trials on their use. It discusses explanations for unfavorable outcomes, proposed enhancement techniques and a potential niche for the use of BVS.

Numerical study of incomplete stent apposition caused by deploying undersized stent in arteries with elliptical cross-sections

Incomplete stent apposition (ISA) is one of the causes leading to post-stent complications, which can be found when an undersized or under-expanded stent is deployed at lesions. Previous research efforts have focused on ISA in idealized coronary arterial geometry with circular cross-sections. However, arterial cross-section eccentricity plays an important role in both location and severity of ISA. Computational fluid dynamics (CFD) simulations are carried out to systematically study the effects of ISA in arteries with elliptical cross-sections, as such stents are partially embedded on the minor axis sides of the ellipse and malapposed elsewhere. Overall, ISA leads to high time-averaged WSS (TAWSS) at the proximal end of the stent and low TAWSS at the ISA transition region and the distal end. Shear rate depends on both malapposition distance and blood stream locations, which is found to be significantly higher at the inner stent surface than the outer surface. The proximal high shear rate signifies increasing possibility in platelet activation, when coupled with low TAWSS at the transition and distal region which may indicate a nidus for in-stent thrombosis.

Characteristics and outcome of patients with complex coronary lesions treated with bioresorbable scaffolds: three-year follow-up in a cohort of consecutive patients

AIMS

The safety of bioresorbable scaffolds (BRS) has recently been challenged. However, it is unclear whether outcomes depend on the complexity of the lesion or on the technique used to implant the device. The aim of this study was to report on the outcomes after BRS implantation in complex lesions.

METHODS AND RESULTS

This investigator-initiated, single-centre, single-arm observational study recruited 657 consecutive patients (79% male, 66.7% acute coronary syndrome, age 63±12 years). Three hundred and twenty-two lesions (42.3%) in 297 (45.2%) patients with type B2 or C lesions were classified as the "complex lesions group". Post-procedural residual stenosis was slightly but significantly greater in the complex lesions group (15.7±11.3% vs. 13.5±10.2%, p=0.0109). The median follow-up was 1,076 (762-1,206) days without difference between groups. The Kaplan-Meier rates of early scaffold thrombosis (3.5% vs. 1.1%, p=0.0478, HR 3.03 [1.06-8.70]) and scaffold restenosis (9.9% vs. 9.1%, p=0.0262, HR 2.34 [1.11-4.94]) were higher in patients with complex lesions than in those with simple lesions. Late/very late thrombosis, death, repeat myocardial infarction, or repeat coronary interventions were not different. In patients in whom strict guidelines for implantation were applied, the incidence of thrombosis was reduced by 76% in complex lesions and by 92% in simple ones, such that there were no differences between groups (2.3% vs. 0.5%, p=0.3899). In contrast, the incidence of scaffold restenosis was reduced by 59% and 89%, and a difference between groups persisted (7.0% vs. 1.6%, p=0.0235).

CONCLUSIONS

BRS implantation in complex lesions is, as expected, associated with higher incidence of events as compared to simple ones. The technique used at the time of the implantation, however, reduces the incidence of adverse outcomes.

Branch ostial optimization treatment and optimized provisional t-stenting with polymeric bioresorbable scaffolds: Ex-vivo morphologic and hemodynamic examination

The optimal side-branch (SB) ostium treatment after provisional side-branch scaffolding remains a subject of debate in bioresorbable vascular scaffold (BVS) era. In this study, we evaluated a novel optimized provisional T-stenting technique (OPT) and assessed its feasibility by comparison with T and small protrusion technique (TAP).Two provisional SB scaffolding techniques (OPT, n = 5; TAP, n = 5) were performed using polymeric BVS in a bifurcated phantom. The sequential intermediate snuggling balloon dilation, also called ostial optimal technique, was added to OPT but not TAP to dilate the side-branch ostium while the final snuggling balloon dilation applied for both procedures. Microcomputed tomography (microCT) and optical coherence tomography (OCT) were performed to assess morphology, and computational fluid dynamics (CFD) was performed to assess hemodynamics in the scaffolded bifurcations. Compared with TAP in microCT analysis, OPT created shorter neo-carina length than TAP (0.34 ± 0.10 mm vs 1.02 ± 0.26 mm, P < .01), longer valgus struts length (2.49 ± 0.27 mm vs 1.78 ± 0.33 mm, P < .01) with larger MB ostial area (9.46 ± 0.04 mm vs 8.34 ± 0.09 mm, P < .01). OCT found that OPT significantly decreased the struts mal-apposition (13.20 ± 0.16% vs 1.94 ± 0.54%, P < .01). CFD revealed that OPT generated more favorable flow pattern than TAP, as indicated by less percent (4.68 ± 1.40% vs 8.88 ± 1.21%, P < .01) of low wall shear stress (<0.4 Pa) along the lateral walls.By using BVSs for bifurcation intervention, the sequential intermediate snuggling balloon dilation is feasible for optimizing ostial SB and facilitating subsequent SB scaffolding. Results show OPT is better than TAP for bifurcated morphology and hemodynamics in this ex-vivo study.

A randomized trial comparing two stent sizing strategies in coronary bifurcation treatment with bioresorbable vascular scaffolds - The Absorb Bifurcation Coronary (ABC) trial

BACKGROUND

Limited information is available on the use of Bioresorbable Vascular Scaffold (BVS) in bifurcations involving significant side branches. When treating bifurcation disease with metal stents, the recommendation is to choose a stent diameter based on the distal main vessel diameter. Whether this sizing strategy is applicable to BVS is currently unknown.

METHODS

We randomised 37 patients undergoing elective PCI for 'false' bifurcation disease (Medina 0,1,0; 1,0,0; 1,1,0) to receive BVS based either on proximal or distal reference diameters. Optical Frequency Domain Imaging (OFDI) measurements were performed pre BVS insertion to obtain proximal and distal reference diameters and post implantation. BVS size was chosen according to the proximal or distal reference diameter as per randomisation. Implantation was performed using the PSP technique tailored to bifurcation stenting. OFDI was repeated post implantation to confirm satisfactory expansion and apposition.

RESULTS

Baseline demographics between the two groups were similar. Patients were aged 62.8 ± 3.3 years; 76% were male. Mean side branch diameter was 2.24 ± 0.13 mm. TIMI III flow in the main vessel was achieved in all cases. Side branch occlusion occurred in 1 case (2.7%). In the distal-sizing arm, there was a greater incidence of significant malapposition (>300 μm) at the proximal end of the scaffold on OCT (2.3% versus 0.8%, p 0.023). The incidence of distal edge dissections was numerically greater in the proximal-sizing group but this was not statistically significant (31.3% vs 11.8%, p 0.17).

CONCLUSION

Both proximal and distal sizing strategies have similar procedural complication rates when using the ABSORB BVS to treat coronary bifurcations. However a proximal sizing strategy is associated with less malapposition and may be preferable.

Optical coherence tomographic analysis of drug-eluting in-stent restenosis at different times: A STROBE compliant study

The imaging characteristics of drug-eluting in-stent restenosis (ISR) at different times varied; however, the mechanism had not yet been elucidated.To analyze the imaging characteristics of drug-eluting ISR at different time points by optical coherence tomography (OCT) and investigate the cause of the stent treatment failure.A total of 70 patients with drug-eluting ISR undergoing OCT were enrolled (intimal hyperplasia ≥50% of stent area) and implanted with drug-eluting stents. According to stent implantation time, the patients were divided into 2 groups: early in-stent restenosis group (E-ISR group) (group A, n = 35, stent age ≤12 months) and late in-stent restenosis group (L-ISR group) (group B, n = 35, stent age ≥24 months). A qualitative analysis of the restenosis tissue included the nature of restenosis tissue (homogeneous and heterogeneous), neoatherosclerosis, thin-cap fibroatheroma (TCFA), and microvessels.The ratio of ≥75% cross-sectional area stenosis between the L-ISR and E-ISR groups was (60.00% vs 34.28%, P < .05). The heterogeneous intima, neoatherosclerosis, TCFA, and microvessels were more prevalent in the L-ISR group as compared to the E-ISR group (71.43% vs 45.71%, P < .05; 48.57% vs 22.86%, P < .05; 25.71% vs 5.71%, P < .05; 22.86% vs 2.86%, P < .05, respectively).The morphological characteristics of L-ISR were significantly different from those in the E-ISR; the former was closer to the atherosclerotic plaque, which provided a new approach for the treatment of drug-eluting ISR.

Optical coherence tomography guidance during bioresorbable vascular scaffold implantation

Bioresorbable vascular scaffold (BRS) represent a revolutionary concept in interventional cardiology. After initial enthusiasm, recent real world registries, including patients with increasing lesion complexity, reported not trivial rates of scaffold thrombosis (ScT). The importance of correct patients selection as well as technical aspects during BRS implantation procedures has been highlighted in several studies suggesting that the high rate of ScT might be related to uncorrected patients/lesions selection together with underutilization of intracoronary imaging guidance leading to suboptimal BRS implantation. The high-resolution power together with the lack of shadowing observed beyond polymer struts makes optical coherence tomography (OCT) the optimal imaging technique to guide BRS implantation and identifies eventually scaffolds failures.

BRS implantation in long lesions requiring device overlapping: myth or reality?

Dealing with bioresorbable vascular scaffolds (BVS) implantation in long lesions requiring device overlapping in this particular moment might seem a little provocative for several reasons. First, most studies testing BVS have focused on their safety and efficacy profile in simple patients with simple lesions. Second, ABSORB II did not meet its primary endpoint, while ABSORB III showed a higher rate of target vessel-myocardial infarction (TV-MI) at 2 years. Third, data on porcine model showed that overlapping zone has delayed but greater neointimal proliferation with consequent higher risk for scaffold thrombosis in the short-term and of in-scaffold restenosis in the long-term. Fourth, recently published data showed higher risk of TVF in patients treated with ≥60 mm BVS. Given all these premises, it may seem right to put aside this technology, while it may seem inappropriate to hypothesize the use of BVS in long lesions. The aim of the present review is precisely to critically review the available evidences regarding BVS with particular regard to overlapping BVS in order to understand whether this technology has a future per se and especially in long coronary lesions requiring overlap.

Long-term outcome of bioresorbable vascular scaffolds for the treatment of coronary artery disease: a meta-analysis of RCTs

BACKGROUND

Coronary bioresorbable scaffolds (BRS) were developed to overcome the limitations of standard metallic stents, especially to address late events after percutaneous coronary interventions. The aim of this meta-analysis was to evaluate the efficacy and safety of BRS, compared with Everolimus-eluting stents (EES), using the data available from randomized trials, with a focus on long-term outcomes.

METHODS

Published randomized trials comparing BRS to EES for the treatment of coronary artery disease were searched for within PubMed, Cochrane Library and Scopus electronic databases up to April 4th 2017. The summary measure used was odds ratio (OR) with 95% confidence intervals.

RESULTS

A total of 5 studies were eligible, including 5219 patients. At 2 years, BRS was associated with higher rates of target lesion failure (9.4% vs 7.2%; OR = 1.33; 95% CI 1.07 to 1.63; p = 0.008) and device thrombosis (2.3% vs 0.7%; OR = 3.22; 95% CI 1.86 to 5.57; p < 0.0001) compared with EES. The incidence of both early (within 30 days after implantation, 1.1% vs 0.5%, OR 1.97, 95% CI 1.02 to 3.81; p = 0.05) and very-late device thrombosis (>1 year, 0.6% vs 0.1%, OR 4.03, 95% CI 1.37 to 11.82; p = 0.01) was higher with BRS compared with EES.

CONCLUSIONS

BRS may be associated with worse two-years clinical outcomes compared with EES in patients with coronary artery disease.

Bioresorbable vascular scaffolds - basic concepts and clinical outcome

The introduction of percutaneous treatment of coronary artery stenosis with balloon angioplasty was the first revolution in interventional cardiology; the advent of metallic coronary stents (bare and drug-eluting) marked the second and third revolutions. However, the latest generation of drug-eluting stents is limited by several factors. Permanent vessel caging impairs arterial physiology, and the incidence of very late stent thrombosis - although lower with the second generation than with the first generation of drug-eluting stents - remains a major concern. This complication is mainly related to the presence of permanent metallic implants, chronic degeneration triggered by an inflammatory response to the coating polymer, and/or adverse effects of antiproliferative drugs on endothelial regeneration. In 2011, self-degrading coronary stents - the bioresorbable vascular scaffolds (BVS) - were introduced into clinical practice, showing good short-term results owing to their adequate strength. The advantage of these devices is the transient nature of vascular scaffolding, which avoids permanent vessel caging. In this Review, we summarize the latest research on BVS, with a particular emphasis on the implantation technique (which is different from that used with metallic stents) to outline the concept that BVS deployment methods have a major effect on procedural success and prognosis of patients with coronary artery stenosis. Furthermore, the clinical outcome of BVS in randomized clinical trials and in phase IV studies are discussed in different pathophysiological settings, such as stable or acute coronary disease. Finally, all the available data on the safety profile of BVS regarding scaffold thrombosis are discussed.