Persistent platelet reactivity in patients with unprotected left main disease treated by percutaneous coronary intervention

Abstract

Purpose: Angioplasty is emerging as an alternative technique for patients with unprotected left main disease (ULMD). Persistent platelet reactivity (PPR) under aspirin or thienopyridines is associated with acute events after angioplasty. We aimed to determine the rate and potential clinical impact of PPR in patients treated by angioplasty for ULMD. Methods: We prospectively included 125 patients referred for angioplasty for ULMD in a single-centre registry. For the first 64 patients (ALMA-1), angioplasty was performed under aspirin and clopidogrel treatment without previous platelet reactivity assessment. For the last 61 patients (ALMA-2), platelet reactivity was assessed (light transmission aggregometry triggered by arachidonic acid and ADP and VASP index) systematically before angioplasty: patients found to have aspirin-related PPR were administered aspirin twice daily and those with clopidogrel-related PPR had their daily clopidogrel dose doubled or replaced by prasugrel. Results: Overall, patients mean age was 69±13y.o., 37% were diabetic, 37% had NSTEMI and 62% had multivessel disease. The left main lesion was ostial in 23%, medial in 8% and distal or both in 69%. Mean SYNTAX score was 22.8±9.2. More than 30% of the patients have an additive EuroSCORE≥6. Procedural characteristics were similar in both groups. Follow-up was successful at 1 year in all patients. In ALMA-2, concerning aspirin pathway, mean maximal aggregation intensity (MAI) was 15.4±17.0%. The proportion of patients with aspirin-related PPR (MAI≥20%) was 28% and aspirin was switched twice a day in those patients. Concerning thienopyridines pathway, mean MAI triggered by ADP 20μmol was 53.6±18.5%, mean VASP index was 46±19% and considering both MAI>65% and VASP>50%, 26% of patients (n=16) had PPR under thienopyridines. Following these results, 31% of patients (n=19) were switched to prasugrel and 26% (n=16) were treated by high-dose clopidogrel. Finally, 8% of patients (n=5) had PPR under both, aspirin and thienopyridine treatment. Dual antiplatelet therapy at 1 year was continued in 86% of patients in ALMA-1 and 92% in ALMA-2 (p=NS). The rate of 1-year major cardiovascular events was significantly decreased in ALMA-2 vs. ALMA-1 (8.2% vs. 20.8%; p=0.04) as a composite endpoint of cardiovascular death and stent thrombosis (0.0% vs. 8.3%; p=0.02). Conclusion: In our real life study, PPR for dual antiplatelet therapy is frequent in patients undergoing angioplasty for ULMD and appears to be strongly associated with subsequent major events.