Bioresorbable Scaffolds vs. Metallic Stents in Routine PCI
What is the safety and efficacy of an everolimus-eluting bioresorbable scaffold as compared with an everolimus-eluting metallic stent in the context of routine clinical practice?
The AIDA (Amsterdam Investigator-initiateD Absorb strategy all-comers) trial was an investigator-initiated, randomized trial to compare an everolimus-eluting bioresorbable scaffold with an everolimus-eluting metallic stent. The investigators randomly assigned 1,845 patients undergoing PCI to receive either a bioresorbable vascular scaffold (924 patients) or a metallic stent (921 patients). The primary endpoint was target-vessel failure (a composite of cardiac death, target-vessel myocardial infarction, or target-vessel revascularization). The data and safety monitoring board recommended early reporting of the study results because of safety concerns. This report provides descriptive information on endpoint events.
The median follow-up was 707 days. Target-vessel failure occurred in 105 patients in the scaffold group and in 94 patients in the stent group (2-year cumulative event rates, 11.7% and 10.7%, respectively; hazard ratio, 1.12; 95% confidence interval [CI], 0.85-1.48; p = 0.43); event rates were based on Kaplan–Meier estimates in time-to-event analyses. Cardiac death occurred in 18 patients in the scaffold group and in 23 patients in the stent group (2-year cumulative event rates, 2.0% and 2.7%, respectively), target-vessel myocardial infarction occurred in 48 patients in the scaffold group and in 30 patients in the stent group (2-year cumulative event rates, 5.5% and 3.2%), and target-vessel revascularization occurred in 76 patients in the scaffold group and in 65 patients in the stent group (2-year cumulative event rates, 8.7% and 7.5%). Definite or probable device thrombosis occurred in 31 patients in the scaffold group as compared with eight patients in the stent group (2-year cumulative event rates, 3.5% vs. 0.9%; hazard ratio, 3.87; 95% CI, 1.78-8.42; p < 0.001).
The authors concluded that the bioresorbable scaffold was associated with a higher incidence of device thrombosis than the metallic stent through 2 years of follow-up.
This study reports that the rate of definite or probable device thrombosis in the scaffold group was approximately 3.5 times as high as that in the stent group over the course of 2 years. Furthermore, the higher incidence of scaffold thrombosis was associated with a significantly higher incidence of myocardial infarction. The rate of the primary composite endpoint of target-vessel failure, as well as the rates of death from any cause, cardiac death, and revascularizations, did not differ significantly between the two study groups. Given that the current generation of bioresorbable scaffold takes longer to implant, is more expensive, is less safe, and is no more effective than metallic drug-eluting stents, there is little rationale to implant them over metallic drug-eluting stents, which provide excellent long-term outcomes.
Keywords: Absorbable Implants, Drug-Eluting Stents, Incidence, Myocardial Infarction, Myocardial Revascularization, Percutaneous Coronary Intervention, Stents, Thrombosis
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