Efficacy and safety of polymer-free stent versus polymer-permanent drug-eluting stent in patients with acute coronary syndrome: a meta-analysis of randomized control trials

Drug-Eluting Stents: Technical and Clinical Progress

Drug-eluting stents (DES) demonstrated superior efficacy when compared to bare metal stents and plain-old balloon angioplasty and are nowadays used in almost all percutaneous revascularization procedures. The design of the stent platforms is constantly improving to maximize its efficacy and safety. Constant development of DES includes adoption of new materials used for scaffold production, new design types, improved overexpansion abilities, new polymers coating and, finally, improved antiproliferative agents. Especially nowadays, with the immense number of available DES platforms, it is crucial to understand how different aspects of stents impact the effect of their implantation, as subtle differences between various stent platforms could impact the most important issue-clinical outcomes. This review discusses the current status of coronary stents and the impact of stent material, strut design and coating techniques on cardiovascular outcomes.

Stent Thrombosis After Percutaneous Coronary Intervention: From Bare-Metal to the Last Generation of Drug-Eluting Stents

Since their introduction in clinical practice in 1986, different types of coronary stents have been developed and become available for the treatment of coronary artery disease. Stent thrombosis (ST) is an uncommon but harmful complication after percutaneous coronary implantation, with a high occurrence of acute myocardial infarction and risk of mortality. Among several procedural and clinical predictors, the type of coronary stent is a strong determinant of ST. This article reviews the available evidence on the most used coronary stent types in the modern era and the related risk of ST.

Safety and efficacy of the polymer-free and polymer-coated drug-eluting stents in patients undergoing percutaneous coronary intervention

INTRODUCTION

The relative safety and efficacy of polymer-free (PF) versus polymer-coated (PC) drug-eluting stents (DES) in patients with angina or acute coronary syndrome (ACS) undergoing percutaneous coronary intervention has received limited study.

METHOD

Digital databases were queried to identify relevant studies. Major adverse cardiovascular events (MACE) and secondary outcomes were compared using a random effect model to calculate unadjusted odds ratios (OR).

RESULTS

A total of 28 studies consisting of 23,198 patients were included in the final analysis. On pooled analysis, there was no significant difference in the odds of MACE (OR 0.98, 95% CI 0.91-1.08) and major bleeding (OR 0.87, 95% CI 0.61-1.24) between patients undergoing PF-DES versus PC-DES. Similarly, the odds of myocardial infarction, stroke, stent thrombosis, cardiovascular mortality and need for target vessel revascularization was similar between the two groups. PF-DES was favored due to significantly lower odds of non-cardiac death (OR 0.78, 95% CI 0.68-89) and all-cause mortality (OR 0.87, 95% CI 0.80-0.95), but had a higher need for target lesion revascularization (OR 1.2, 95% CI 1.02-1.42). A subgroup analysis based on follow up duration, clinical presentation, presence of diabetes and class of eluting drugs mirrored the net estimates for all outcomes with a few exceptions. A sensitivity and meta-regression analysis showed no influence of single-study and duration of antiplatelet therapy on pooled outcomes.

CONCLUSION

In patients presenting with angina or ACS, PF-DES might be favored due to lower all-cause mortality and equal risk of ischemic adverse cardiovascular and major bleeding events compared with PC-DES.

Stent Thrombosis After Percutaneous Coronary Intervention: From Bare-Metal to the Last Generation of Drug-Eluting Stents

Since their introduction in clinical practice in 1986, different types of coronary stents have been developed and become available for the treatment of coronary artery disease. Stent thrombosis (ST) is an uncommon but harmful complication after percutaneous coronary implantation, with a high occurrence of acute myocardial infarction and risk of mortality. Among several procedural and clinical predictors, the type of coronary stent is a strong determinant of ST. This article reviews the available evidence on the most used coronary stent types in the modern era and the related risk of ST.

Polymer-Free vs. Polymer-Coated Drug-Eluting Stents for the Treatment of Coronary Artery Disease: A Meta-Analysis of 16 Randomized Trials

BACKGROUND

Polymer-coating represents one of components of drug-eluting stents (DES) to have experienced a more intensive technological evolution. Polymer-free DES (PF-DES) have offered promising angiographic results, with earlier complete re-endothelization, potentially reducing the thrombotic risk and offering the option of a shorter antiplatelet therapy. However, contrasting prognostic data have been reported so far with PF-DES. Therefore, the aim of the present study was to perform a comprehensive updated meta-analysis of randomized trials (RCT) comparing the impact of PF-DES vs polymer- coated DES (PC-DES) on clinical outcome.

METHODS

Literature and main scientific session abstracts were searched for RCTs comparing PF-DES vs PC-DES for the treatment of CAD. The primary efficacy endpoint was mortality, secondary endpoints were cardiovascular death, myocardial infarction, target lesion revascularization (TLR) and stent thrombosis.

RESULTS

We included 16 randomized clinical trials, with a total of 15,689 patients, including 50.6% randomized to PF-DES. At a median follow-up of 24 months, PF-DES were associated to a significant reduction in mortality as compared to PC-DES (0.82 [0.68, 0.99], p = .03, I2 = 0%; phet = 0.93). However, no significant benefit was observed in terms of cardiovascular death or major ischemic endpoints (respectively CV death: OR [95% CI] = 0.92 [0.71, 1.18] p = .50, I2 = 0.50; phet = 0.84; MI: OR [95% CI] = 1.08 [0.90, 1.29], p = .42; I2 = 0%, phet = 0.98; TLR: OR [95% CI] = 1.02 [0.78, 1.32], p = .91; I2 = 0.63 phet = 0.0003; ST: OR [95% CI] = 0.98 [0.87, 1.10], p = .72; I2 = 0% phet = 0.64). By meta-regression analysis, the mortality benefits of PF-DES were not conditioned by the rate of diabetes mellitus or acute coronary syndromes.

CONCLUSIONS

Based on the current meta-analysis, PF-DES are associated to a significant reduction in mortality as compared to PC-DES, but not in the occurrence of major ischemic events. Future larger studies are certainly needed to further investigate and confirm our findings, especially in particular subsets of patients, such as those with high bleeding risk or acute myocardial infarction.