Post-dilatation after implantation of bioresorbable everolimus- and novolimus-eluting scaffolds: an observational optical coherence tomography study of acute mechanical effects

Long-term outcomes following bioresorbable vascular scaffolds

INTRODUCTION

The higher scaffold thrombosis rates observed with the first-generation bioresorbable scaffolds (BRSs) compared to conventional drug-eluting stents were likely due in part to bioresorbable polymers having insufficient radial strength, necessitating larger strut profiles. Meta-analysis of the long-term outcomes from the first-generation Absorb bioresorbable vascular scaffold (BVS) showed that this period of excess risk ended at 3 years. Therefore, current attention has been focused on improving early outcomes by increasing the scaffold's tensile strength and reducing strut thickness.

AREAS COVERED

This review summaries the lessons learned from the first-generation BRS. It updates the long-term clinical outcomes of trials evaluating the ABSORB BVS and metallic alloy-based BRS. In addition, it reviews the next-generation BRSs manufactured in Asia.

EXPERT OPINION

Critical areas to improve the performance and safety of biodegradable scaffolds include further development in material science, surface modification, delivery systems, and long-term follow-up studies.

Dissections after bioresorbable vascular scaffold implantation in the POLAR ACS Registry

Introduction

Percutaneous coronary intervention (PCI) is a common method of treatment for patients with coronary artery disease. One of the most common complications during the PCI procedure is coronary artery dissection. It usually requires an additional action to assure the patency of the treated vessel.

Aim

The aim of the publication is to describe the occurrence of coronary artery dissection after bioresorbable vascular scaffold (BVS) implantation. This selected type of PCI procedure is especially interesting because precise target vessel measurement before BVS implantation is required for optimal determination of scaffold size.

Material and methods

Based on angiographic data gathered in the POLAR ACS Registry, we assessed the frequency of dissections, their localization, and severity. Based on data regarding patients’ demographic, clinical status, and details regarding treatment strategy, the factors that could have an influence on the dissection occurrence were identified.

Results

A group of 100 patients included in the analyses. Group A consisted of 9 patients. This group was defined as patients in whom the significant dissection occurred after the BVS implantation. Group B comprised 91 patients. Both groups were very similar according to demographic data. The frequency of predilatation was similar; post-dilatation was performed more often in group A but without statistical significance. The presence of calcification in the target lesion was an independent factor of dissection during the index PCI procedure.

Conclusions

The occurrence of significant dissection can be effectively treated, and the good angiographic results of this treatment immediately after the initial procedure translate into good clinical results in longer follow-up.

Acute Mechanical Performance of Magmaris vs. DESolve Bioresorbable Scaffolds in a Real-World Scenario

Background: After the bioresorbable PLLA-based vascular scaffold (Absorb BVS) was taken from the market due to its high adverse event rates, a magnesium-based scaffold (Magmaris) was introduced. Objective: To compare the acute performance of the sirolimus-eluting magnesium alloy Magmaris scaffold with that of the novolimus-eluting PLLA-based DESolve scaffold in terms of appropriate scaffold deployment using optical coherence tomography (OCT). Methods and Results: Data from the final OCT pullback of 98 patients were included (19 Magmaris, 79 DESolve) and analyzed at 1-mm intervals. The following indices were calculated: mean and minimal area, residual area stenosis, incomplete strut apposition, tissue prolapse, eccentricity index, symmetry index, strut fracture, and edge dissection. OCT showed a minimum lumen area for Magmaris vs. DESolve of 6.6 ± 1.6 vs. 6.0 ± 1.9 (p = 0.06). Scaffolds with residual area stenosis >20% were predominantly seen in the DESolve group (15.8 vs. 46.8%; p = 0.01). The mean eccentricity index did differ significantly (0.74 ± 0.06 vs. 0.63 ± 0.09; p < 0.001). No fractures were observed for Magmaris scaffolds, but 15.2% were documented for DESolve BRS (p < 0.001). Incomplete scaffold apposition area was significantly higher in the DESolve group (0.01 ± 0.02 vs. 1.05 ± 2.32 mm²; p < 0.001). Conclusion: This is the first study to compare the acute mechanical performance between Magmaris and DESolve in a real-world setting. The acute mechanical performance of Magmaris BRS seems to be superior to that of DESolve BRS, whereas OCT showed a good acute mechanical performance for both BRS in terms of generally accepted imaging criteria.

Comparison between treatment of "established" versus complex "off-label" coronary lesions with Absorb® bioresorbable scaffold implantation: results from the GABI-R® registry

OBJECTIVES

The purpose of this study was to compare the clinical outcomes of patients treated with bioresorbable scaffold (BRS) for off-label versus approved indications.

BACKGROUND

The BRS promised some advantages in terms of complete biodegradation within 2-4 years, restored vascular physiology, and absence of potential stent-related long-term complications. However, the implication of BRS for off-label indications and further long-term follow-up of this particular patient group is not well described.

METHODS

The short- and long-term outcome after implantation of an everolimus-eluting, poly-L-lactic acid-based bioresorbable scaffold system (ABSORB, Abbott Vascular, Santa Clara, CA, USA) was evaluated in the prospective, non-interventional, multicenter real-world German-Austrian ABSORB RegIstRy (GABI-R).

RESULTS

A total of 3188 patients were enrolled. Patients were divided into two groups: on-label BRS use (33.0%) and off-label use (66.9%) if at least one off-label use criteria was met. The incidence of scaffold thrombosis in confirmed cases was significantly higher in off-label group (1.3% versus 0.5%, p = 0.04; OR 2.41 (95% CI 1.00-5.82) with also a trend toward higher myocardial infarction rate (2.3% versus 1.4%, p = 0.077; OR 1.70 (95% CI 0.95-3.03) and cardiovascular death (1.2% versus 1.1%, p = 0.76, OR 1.11 (95% CI 0.56-2.21) at 6-month follow-up.

CONCLUSIONS

In a real-world setting, the majority patients were treated with BRS for off-label indications. The off-label use of BRS compared to confirmed indications appears to be associated with a higher rate of clinical endpoints considering more complex lesions and higher morbidity in this patients' group. Comparison between treatment of "established" versus complex "off-label" coronary lesions with Absorb^® bioresorbable scaffold implantation: results from the GABI-R^® registry.

Predictors for target lesion microcalcifications in patients with stable coronary artery disease: an optical coherence tomography study

BACKGROUND

The minimal fibrous cap thickness overlying the necrotic lipid core as well as the presence of macrophages are established characteristics of coronary plaque vulnerability. Recently, the presence of microcalcifications has emerged as a novel feature of vulnerable lesions. However, clinical and plaque morphological predictors of microcalcifications are unknown.

METHODS

In patients with stable coronary artery disease, analysis of plaque morphology (n = 112) was performed using optical coherence tomography prior to coronary intervention to assess predictors of microcalcifications.

RESULTS

Microcalcifications were present in 21/112 (18.7%) lesions. Segments with microcalcifications showed a higher total number of calcifications per lesion (6.7 ± 3.0 vs. 3.2 ± 2.5, p < 0.001), a lower percent area stenosis (70.9 ± 11.1 vs. 76.2 ± 9.7%, p = 0.028), and a higher frequency of macrophage infiltration (66.7 vs. 37.4%, p = 0.014). In lesions with vs. without microcalcifications, macrophage infiltration was characterized by a wider macrophage angle (31.1° ± 34.4° vs. 13.7° ± 20.6°, p = 0.003), a higher macrophage index (105.6 ± 269.0 vs. 31.6 ± 66.5° mm, p = 0.020), and an increased frequency of calcium-macrophage co-localization (47.6 vs. 15.6%, p = 0.001). In multivariable logistic regression analysis, the total number of calcifications per lesion (OR 1.53, 95% CI 1.23-1.91, p < 0.001), average macrophage angle (OR 1.28 for 10°-variation, 95% CI 1.03-1.60, p = 0.024), and percent area stenosis (OR 0.59 for 10% increase, 95% CI 0.34-1.04, p = 0.070) were independent predictors for the presence of microcalcifications, whereas the latter did not reach statistical significance.

CONCLUSION

Microcalcifications are related to a less advanced stenosis severity and to extensive plaque inflammation, but not to clinical parameters. Our data may add to the understanding and role of microcalcifications in coronary artery lesions.