Long-term outcome of first 300 implanted Absorb bioresorbable vascular scaffolds in an all-comers Middle East population

An integrated mechanical degradation model to explore the mechanical response of a bioresorbable polymeric scaffold

Simulation of bioresorbable medical devices is hindered by the limitations of current material models. Useful simulations require that both the short- and long-term response must be considered; existing models are not physically-based and provide limited insight to guide performance improvements. This study presents an integrated degradation framework which couples a physically-based degradation model, which predicts changes in both crystallinity (Xc) and molecular weight (Mn), with the results of a micromechanical model, which predicts the effective properties of the semicrystalline polymer. This degradation framework is used to simulate the deployment of a bioresorbable PLLA (Poly (L-lactide) stent into a mock vessel and the subsequent mechanical response during degradation under different diffusion boundary conditions representing neointimal growth. A workflow is established in a commercial finite element code that couples both the immediate and long-term responses. Clinically relevant lumen loss is reported and used to compare different responses and the effect of neo-intimal tissue regrowth post-implantation on degradation and on the mechanical response is assessed. In addition, the effects of possible changes in Xc, which could occur during processing and stent deployment, are explored.

Four-Year Outcomes of Left Main Percutaneous Coronary Intervention with a Bioresorbable Scaffold in the Circumflex Ostium

Objectives. The study aimed to investigate the long-term outcomes of a double stent scaffold strategy in patients with left main (LM) bifurcation lesions involving the ostium of the left circumflex artery (LCX), utilizing a drug-eluting stent (DES) in the LM extending into the left anterior descending artery (LAD) and a bioresorbable vascular scaffold (BVS) in the LCX ostium. Background. The high occurrence of in-stent restenosis of the LCX ostium is the major limitation of percutaneous coronary intervention (PCI) for LM lesions with a two-stent strategy. Methods. This was a single-center, prospective, single-arm study of 46 consecutively enrolled patients with a stable coronary artery disease and significant unprotected LM distal bifurcation disease. Patients underwent imaging-guided PCI using DES in the LM-LAD and BVS in the LCX using a T-stent or mini-crush technique. The primary outcome at four years was the composite of death, myocardial infarction, stroke, and target lesion revascularization (TLR). Results. At four years, the primary outcome was identified in 9 patients (19.6%). All events were TLRs except one myocardial infarction due to BVS thrombosis. Seven of the eight TLRs were a result of side branch BVS restenosis. Univariate predictors of the 4-year outcome were higher LDL cholesterol and BVS size ≤2.5 mm. On multivariate analysis, LCX lesion preparation with a cutting balloon and post-procedure use of intravascular ultrasound for optimization were found to be independent protective factors of MACE. Conclusions. In selected patients with LM distal bifurcation disease, an imaging-guided double stent scaffold strategy with DES in the LM and BVS in the LCX ostium was technically successful in all patients and was reasonably safe and effective for four years.

The role of optical coherence tomography guidance in scaffold versus stent optimization

BACKGROUND

Optical coherence tomography showed a great ability to identify adverse features during percutaneous coronary intervention with drug-eluting stents and resulted in better clinical outcomes. The study aimed to assess the impact of optical coherence tomography on intraoperative decision-making during implantation of Absorb bioresorbable scaffolds versus everolimus drug-eluting stents.

RESULTS

We performed an observational study that included 223 consecutive patients post optical coherence tomography-guided implantation of either Absorb bioresorbable scaffolds (162 patients) or everolimus drug-eluting stents (61 patients). We studied the influence of optical coherence tomography on intraoperative decision-making during implantation of bioresorbable scaffolds versus drug-eluting stents by analyzing the total rate of optical coherence tomography-dependent modifications in each device. After satisfactory angiographic results, the total rate of required intervention for optical coherence tomography detected complications was significantly higher in the bioresorbable scaffolds arm compared to drug-eluting stents arm (47.8% versus 32.9%, respectively; p = 0.019). The additional modifications encompassed further optimization in the case of device underexpansion or struts malapposition, and even stenting in the case of strut fractures, or significant edge dissection.

CONCLUSIONS

Compared to drug-eluting stents, Absord scaffold was associated with a significantly higher rate of optical coherence tomography-identified intraprocedural complications necessitating further modifications. The study provides some hints on the reasons of scaffolds failure in current PCI practice; it offers a new insight for the enhancement of BRS safety and presents and adds to the growing literature for successful BRS utilization.