Do Polymers Play any Role in Drug Eluting Stents

The fact that polymers can degrade after drug release seems interesting, more so when there appears to be evidence that they might cause inflammation (manly eosinophil infiltration) given its unwanted consequences. However, nice theories often get a reality check, and the polymer discussion is no exception.

This article, soon to be published in J Am Coll Cardiol Intv, enrolled 7042 consecutive daily routine patients and was unable to show any differences between permanent polymer and bioresorbable polymer devices at 12 months. In fact, there was acute stent thrombosis with bioresorbable polymer devices that did not differ from permanent polymer devices after 12 months.

The aim of this study was to compare the safety and efficacy of a thin-strut biodegradable polymer everolimus eluting stent (Synergy) vs. and a thin-strut, durable-polymer everolimus-eluting stent (Xience) in a population with practically no exclusion criteria.

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Between 2012 and 2016, 3870 patients were exclusively treated with one kind of stent (Xience n= 2527 and Synergy n=1343). Propensity score was used to account for differences on baseline characteristics, leaving 1041 patients in each branch. Primary end point was a composite of cardiac death, target vessel infarction and target lesion revascularization at one year.

The combined end point was similar between both branches (7.8% for Synergy vs 7.1% for Xience; p=0.49). Separate components of primary end point also resulted similar (cardiac death 3% vs 3%, target vessel infarction 3.6% vs 3.1% and target lesion revascularization 3% vs 2.5%; all non-significant).

Acute stent thrombosis rate was significantly higher for the Synergy (1.2% vs 0.3%; p=0.032). At 12 months, definite thrombosis rate resulted similar (1.5% for Synergy vs 0.9% for Xience; p=0.22).

Conclusion

In this consecutive population that reflects the daily clinical practice there were no differences between the resorbable polymer and the permanent polymer drug eluting stents at one year. The highest rate of acute thrombosis happened with biodegradable polymer and did not differ after one year.

Original title: Everolimus-Eluting Biodegradable Polymer Versus Everolimus-Eluting Durable Polymer Stent for Coronary Revascularization in Routine Clinical Practice.

Reference: Christian Zanchin et al. J Am Coll Cardiol Intv 2019, Article in press.

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