One-Year Results of Bioresorbable Vascular Scaffolds for Coronary Chronic Total Occlusions

Impact of Selection Preference on Longer-Term Outcomes between Bioresorbable Vascular Scaffold versus Everolimus-Eluting Stent for True Lumen Tracking-Recanalized Chronic Total Occlusion

Creation of sizable subintima during intervention for chronic total occlusions (CTO) could lead to the key selection preference of metallic stents rather than bioresorbable vascular scaffolds (BVS) and then possibly deviate the outcome comparisons in real-world studies. By including recanalized CTO with true lumen tracking, we tested if any selection preference remained and compared the outcomes between everolimus-eluting stent (EES) and BVS implantation.Among 211 consecutive CTO interventions with true lumen tracking from August 2014 to April 2018 when BVS was available, we compared the clinical and interventional features between 28 patients with BVS and 77 patients with EES implantation. With propensity score matching and a median follow-up of 50.5 (37.3-60.3) months, we further assessed 25 patients with BVS and 25 with EES for target vessel failure (TVF: cardiac death, target vessel myocardial infarction, and target lesion revascularization).Multivariate analyses showed that BVS was still favored in the presence of LAD CTO (odds ratio (OR) = 3.4, 95% confidence interval (CI) = 1.0-11.7) and an average scaffold/stent size ≥ 3 mm (OR = 10.5, 95% CI = 3.0-37.3). EES was preferred for lesions with a J-CTO score ≥ 3 (OR = 19.3, 95% CI = 3.4-110.8) and multivessel intervention necessary at index procedure (OR = 11.3, 95% CI = 1.9-67.3). With matched comparisons, the TVF-free survival of EES was better than that of BVS for CTO recanalization (P = 0.049 by log-rank test) at long-term follow-up.Even with true lumen tracking techniques, selection bias remained substantial when determining either device for CTO implantation. The matched comparison of outcomes suggested the unfavorable longer-term impacts of the first generation of BVS on CTO lesions.

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.

Bioresorbable vascular scaffolds for percutaneous treatment of chronic total coronary occlusions: a meta-analysis

BACKGROUND

BRS represent a new approach to treating coronary artery disease. Beneficial properties of BRS regarding the restoration of vasomotility after resorption make them attractive devices in CTO revascularization. However, experience in this setting is limited.

METHODS

We systematically searched Medline, Scholar, and Scopus for reports of at least 9 patients with CTO undergoing BRS implantation. Patients' and procedural characteristics were summarized. The primary outcome of interest was target lesion revascularization (TLR). Pooled estimates were calculated using a random-effects meta-analysis. The study protocol was registered in PROSPERO (CRD42017069322).

RESULTS

Thirteen reports for a total of 843 lesions with a median follow-up of 12 months (IQR 6-12) were included in the analysis. At short-term, the summary estimate rate of TLR was 2.6% (95% CI: 1 to 4%, I2 = 0%, P = 0.887) while at mid to long-term it was 3.8% (95% CI: 2 to 6%, I2 = 0%, P = 0.803). At long-term follow-up (≥12 months), the summary estimate rate of cardiac death was 1.1% (95% CI: 0 to 2%, I2 = 0%, P = 0.887). The summary estimate rates of scaffold thrombosis and clinical restenosis were respectively 0.9% (95% CI: 0 to 2%, I2 = 0%, P = 0.919) and 1.8% (95% CI: 0 to 4%, I2 = 0%, P = 0.448). Finally, the summary estimate rate of target vessel revascularization was 6.6% (95% CI: 0 to 11%, I2 = 0%, P = 0.04).

CONCLUSIONS

Implantation of BRS in a population with CTO is feasible, although further longer-term outcome studies are necessary.

Percutaneous Coronary Intervention in Chronic Total Occlusion

Percutaneous coronary intervention in chronic total occlusion is a rapidly evolving area, being considered the last frontier of interventional cardiology. In recent years, the development of new techniques and equipment, as well as the training of specialized personnel, increased their success rates, making it the most predictable procedure available. Although the number of randomized and controlled studies is still limited, results from large multicentered registries allow us to safely offer this intervention to patients, as another treatment option along with the optimized drug treatment and myocardial revascularization surgery. This review summarizes the last and most relevant publications in the subject in order to provide an overall view of the field’s current status.

Vascular response and healing profile of everolimus-eluting bioresorbable vascular scaffolds for percutaneous treatment of chronic total coronary occlusions: A one-year optical coherence tomography analysis from the GHOST-CTO registry

BACKGROUND

Bioresorbable vascular scaffolds (BVS) have been heralded with potential benefits that are especially desired in long lesions, including chronic total occlusions (CTOs). Procedural feasibility and mid-term outcomes of BVS in CTOs have been reported. However, there is still a paucity of data regarding the vascular and healing response to BVS in CTOs evaluated by optical coherence tomography (OCT).

METHODS

This study included prospectively 21 patients who had a CTO lesion treated with a BVS. Angiography and OCT scan were recorded at either post-implantation and 1-year follow-up. Quantitative coronary angiography and OCT analyses were performed by an independent core laboratory.

RESULTS

The angiographic analysis showed a significant increase in the percentage of in-segment diameter stenosis at 1year (11.89±9.5% vs. 21.84±11.7%; p=0.002). The OCT analysis showed a trend (p=0.07) towards increased mean scaffold area and significant reductions in mean lumen diameter (3.1±0.36mm vs. 2.85±0.47mm; p=0.0046), mean lumen area (7.8±1.73mm² vs. 6.76±2mm²; p=0.0082) and minimal lumen area (5.26±1.86mm² vs. 3.56±1.52mm²; p<0.0001). Malapposition area and volume decreased from 0.26±0.17mm² to 0.08±0.1mm² (p=0.0003) and from 14.17±12.92mm³ to 3.99±4.46mm³ (p=0.0014), respectively. The rate of uncovered or malapposed struts, measured at the frame level, was 5.29±6.48% at 1year.

CONCLUSIONS

In a small series of CTO patients treated with BVS implantation, OCT outcomes at 1year displayed an overall favorable vascular response and healing profile.

Procedural and Long-Term Outcomes of Bioresorbable Scaffolds Versus Drug-Eluting Stents in Chronic Total Occlusions: The BONITO Registry (Bioresorbable Scaffolds Versus Drug-Eluting Stents in Chronic Total Occlusions)

BACKGROUND

There is little evidence regarding the efficacy and safety of bioresorbable scaffolds (BRS) for the percutaneous treatment of chronic total occlusions.

METHODS AND RESULTS

We performed a multicenter registry of consecutive chronic total occlusion patients treated with BRS (Absorb; Abbott Vascular) and second-generation drug-eluting stents (DES) at 5 institutions. Long-term target-vessel failure (a composite of cardiac death, target-vessel myocardial infarction, and ischemia-driven target-lesion revascularization) was the primary end point. Inverse probability of treatment weight-adjusted Cox regression was used to account for pretreatment differences between the 2 groups. A total of 537 patients (n=153 BRS; n=384 DES) were included. BRS patients were younger and had lower prevalence of comorbidities. Overall mean Japan-Chronic Total Occlusion (J-CTO) score was 1.43±1.16, with no differences between groups. Procedural success was achieved in 99.3% and 96.6% of BRS- and DES-treated patients, respectively (P=0.07). At a median follow-up of 703 days, there were no differences in target-vessel failure between BRS and DES (4.6% versus 7.7%; P=0.21). By adjusted Cox regression analysis, there were still no significant differences between BRS and DES (hazard ratio, 1.54; 95% confidence interval, 0.69-3.72; P=0.34). However, secondary analyses suggested a signal toward higher ischemia-driven target-lesion revascularization with BRS.

CONCLUSIONS

Implantation of BRS versus second-generation DES in chronic total occlusion was associated with similar risk of target-vessel failure at long-term follow-up. However, a signal toward increased ischemia-driven target-lesion revascularization with BRS was observed. Large randomized studies should confirm these findings.

Bioresorbable vascular scaffolds in coronary chronic total occlusions revascularization: safety assessment related to struts coverage and apposition in 6-month OCT follow-up

Beneficial properties of bioresorbable vascular scaffolds (BVS) regarding to vasomotility restoration and no caging of the vessel make them attractive devices in chronic total occlusions (CTO) revascularization. However, more evidence is needed attending to their use in this specific setting. We aim to determine feasibility and safety of BVS use in CTO revascularization attending to struts coverage and apposition, as well as re-stenosis and stent thrombosis (ST) rates. 29 BVS were deployed in 9 CTO lesions revascularization (mean J-CTO score ≥3) with an acute procedural success rate of 100%. Clinical and angiographic follow-up was performed 6 months later, including intracoronary analyses from optical coherence tomography (OCT) images. 44,723 struts were analyzed within the total 636 mm of scaffolded vessel. Mean length scaffolded per lesion was 70.66 ± 31.01 mm with a mean number of 3.22 BVS. 2051 struts (4.59%) were identified as uncovered, being most of them (98.4%) neither malapposed nor disrupted. Mean thickness of struts' coverage was 0.13 ± 0.05 mm. Incomplete strut apposition (ISA) percentage was 0% as no malapposed struts were detected and 134 struts were identified as disrupted, which represents a 0.29% from the total. Mean vessel, scaffold, and lumen diameters were 3.87 ± 0.51, 2.97 ± 0.49, and 2.68 ± 0.50 mm, respectively. Neither in-stent re-stenosis nor ST was detected. During follow-up, none of our patients died, suffered from stroke or needed target lesion revascularization. Clinical and angiographic 6-month follow-up (including OCT analyses) of BVS in CTO revascularization suggests their effectiveness and safety, even in very complex chronic occluded lesions. Nevertheless, more evidence is needed.

Approach to CTO Intervention: Overview of Techniques

OPINION STATEMENT

Successful percutaneous coronary intervention (PCI) of chronic total occlusions (CTOs) has been associated with significant clinical benefits, but remains technically demanding. Failure to cross the CTO with a guidewire is the most common cause of CTO PCI failure. CTO crossing can be achieved in the antegrade or retrograde direction and can be accomplished by maintaining true lumen position throughout or via subintimal dissection/reentry techniques. A procedural plan should be created prior to the procedure through careful angiographic review of four key parameters: (a) morphology of the proximal occlusion cap; (b) length of the occlusion; (c) quality of the distal vessel and presence of bifurcation at the distal cap; and (d) suitability of collateral circulation for retrograde crossing. Dual coronary injection is recommended in all cases with contralateral collaterals for detailed characterization of the lesion. If one approach fails to progress, a quick transition to the next approach is encouraged to maximize efficacy and efficiency. Procedural complications, including vessel perforation, may occur more frequently in CTO as compared with non-CTO PCI; hence, availability of necessary equipment and expertise in treating such complications are essential.

Bioresorbable Vascular Scaffolds for the Treatment of Chronic Total Occlusions: An International Multicenter Registry

BACKGROUND

There are only limited studies reporting clinical outcomes after bioresorbable vascular scaffold (BVS; Absorb; Abbott Vascular, Santa Clara, CA) implantation for coronary chronic total occlusions (CTO). The aim of this study was to evaluate the real-world feasibility and safety of BVS implantation for the treatment of CTO.

METHODS AND RESULTS

We retrospectively evaluated CTO cases treated with BVS from a multicenter registry. The primary end point was target lesion failure defined as a composite of cardiac death, target vessel myocardial infarction, and clinically driven target lesion revascularization. From September 2012 to November 2015, 65 patients with CTO were successfully treated with BVS. The mean age of patients was 60.8±11.0 years; 89.2% were male and 40.0% diabetic. The mean ejection fraction was 57.7±10.8%. The mean reference vessel diameter and CTO lesion length were 3.0±0.4 and 20.2±3.0 mm, respectively. The mean number of BVS deployed per patient was 1.8±0.7, of which mean diameter and total length were 3.0±0.4 and 47.6±19.9 mm, respectively. Postdilatation with noncompliant balloons (mean diameter 3.3±0.3 mm) was performed at high pressures (18.6±5.3 atm) in all cases. Intravascular ultrasound (n=34) or optical coherence tomography (n=31) was performed in all cases. During the follow-up period (median: 453 days, 25th and 75th percentiles: 230 and 703), there were no occurrences of target lesion failure or scaffold thrombosis.

CONCLUSIONS

BVS implantation for the treatment of CTO seems feasible and safe. Appropriate lesion preparation, high-pressure postdilatation, and the use of intravascular imaging are recommended to obtain the best possible final result.

Bioresorbable scaffolds compared with everolimus-eluting stents for the treatment of chronic coronary total occlusion: clinical and angiographic results of a matched paired comparison

OBJECTIVES

Data on bioresorbable vascular scaffolds for recanalization of chronic total occlusions (CTOs) are limited. We compared the bioresorbable scaffold Absorb with everolimus-eluting stents for the treatment of true CTO.

METHODS

After recanalization of CTO, 15 lesions treated with the bioresorbable scaffold Absorb were matched with 15 lesions receiving everolimus-eluting stent (EES) (http://www.clinicaltrials.gov NCT02162082). Match criteria were presence of diabetes mellitus, total device length and maximal device diameter. Angiographic follow-up was scheduled after 9 months and clinical follow-up after 12 months. Dual antiplatelet therapy was administered for 12 months. Quantitative coronary analysis was carried out before and after implantation and at angiographic follow-up. All lesions were predilated. The Absorb scaffolds and drug-eluting stents were carefully placed and postdilatated with high-pressure balloons. Patients received dual antiplatelet therapy for 12 months. The baseline characteristics were similar between both the groups. The mean scaffold length was 81.7±29.1 versus 79.3±27.4 mm for the mean stent length (P=0.82). In-device late lumen loss at the 9-month follow-up was 0.38±0.47 versus 0.46±0.60 mm (P=0.69). The device-oriented composite endpoint was similar in both groups, with 6.7% in the Absorb-group versus 13.3% in the EES group because of target lesion revascularization (P=0.54).

CONCLUSION

In CTOs, the use of a bioresorbable scaffold Absorb after recanalization showed similar 9-month angiographic and 12-month clinical results compared with an EES with 12 months of dual antiplatelet therapy.

Bioresorbable vascular scaffolds technology: current use and future developments

Coronary bioresorbable vascular scaffolds are a new appealing therapeutic option in interventional cardiology. The most used and studied is currently the Absorb BVS™. Its backbone is made of poly-L-lactide and coated by a thin layer of poly-D,L-lactide, it releases everolimus and is fully degraded to H2O and CO2 in 2-3 years. Absorb BVS™ seems to offer several theoretical advantages over metallic stent, as it gives temporary mechanical support to vessel wall without permanently caging it. Therefore, long-term endothelial function and structure are not affected. A possible future surgical revascularization is not compromised. Natural vasomotion in response to external stimuli is also recovered. Several observational and randomized trials have been published about BVS clinical outcomes. The main aim of this review is to carry out a systematic analysis about Absorb BVS™ studies, evaluating also the technical improvements of the Absorb GT1 BVS™.