Late-breaking trial data presented at EuroPCR 2019 (20–24 May, Paris, France) on three year outcomes of a substudy of patients with small vessel disease in the BIORESORT randomised controlled trial demonstrate significantly lower target lesion revascularisation rates for the Orsiro drug-eluting stent (Biotronik) than for the Resolute Integrity Stent (Medtronic). Presenting on behalf of the investigators, Clemens von Birgelen (Thoraxcentrum Twente, Enschede, the Netherlands) said: “We feel that strut thickness is the most important parameter in this context.”
The subanalysis of the all-comers BIORESORT trial performed two comparisons—one looked at the ultrathin sirolimus eluting stent Orsiro and Resolute Integrity, a thin strut zotarolimus eluting stent; and the second comparison was between Synergy (Boston Scientific), a very thin everolimus-eluting stent and Resolute Integrity. Participants were 1,506 patients with small coronary vessels; 525 were treated with Orsiro, 485 with Resolute Integrity, and 496 with Synergy drug-eluting stent (DES).
Also published in the Journal of the American Medical Association, the findings show the rate of target lesion failure in favour of Orsiro 7% (Orsiro vs. Resolute Integrity p=0.08), for Resolute Integrity 10% and for Synergy 9.5% (Synergy vs. Resolute Integrity p=0.72). The three stents showed similar results for cardiac death and myocardial infarction, and patients treated with Orsiro experienced significantly fewer repeat target lesion revascularisations than those treated with Resolute Integrity (Orsiro 2.1% vs. Resolute Integrity 5.3%, p=0.009; Synergy 4%).
Divergence seemed more pronounced after the first year post-index procedure, after dual antiplatelet therapy (DAPT) was stopped. This is supported in a target lesion revascularistion landmark analysis between one and three years, where the rate with Orsiro was 1%, with Resolute Integrity 3.7% (p=0.006) and with Synergy 2.7%. Additionally, Orsiro showed a trend towards a lower rate of definite or probable stent thrombosis at 0.6% compared to 1.5% for Resolute Integrity (p=0.16) and 1.5% for Synergy.
von Birgelen said: “The results may be clinically relevant, as they suggest a relation between the use of ultrathin strut sirolimus-eluting stents and a lower repeat revascularisation risk in all-comers patients with small target vessels. Due to a greater relative impact of stent strut size on lumen obstruction, the substantially thinner struts of these new-generation drug-eluting stents may be particularly advantageous in small vessels.”
In the large scale, multicentre BIORESORT trial, 42.9% of the full cohort of 3,514 patients undergoing percutaneous coronary intervention presented the need for small vessel treatment. Although stenting of small coronary vessels is relatively common, there are increased risks of subsequent adverse cardiovascular events.