Age and outcomes following guided deescalation of antiplatelet treatment in acute coronary syndrome patients undergoing percutaneous coronary intervention: Results from the randomized TROPICAL-ACS trial

Aims Guided de-escalation of P2Y₁₂-inhibitor treatment was recently identified as an effective alternative treatment strategy in acute coronary syndrome (ACS) patients undergoing percutaneous coronary intervention. Safety and efficacy of this strategy may differ in relation to patient's age. This pre-specified analysis of the TROPICAL-ACS trial aimed to assess the impact of age on clinical outcomes following guided de-escalation of antiplatelet treatment in ACS patients. Methods and results Patients were randomly assigned in a 1:1 fashion to either standard treatment with prasugrel for 12 months (control group) or to a guided de-escalation regimen (1 week prasugrel followed by 1 week clopidogrel and platelet function testing guided maintenance therapy with clopidogrel or prasugrel from day 14 after hospital discharge; guided de-escalation group). We used Cox regression models to assess the associations of age on clinical endpoints and interactions. In younger patients (age ≤70, n = 2240), the 1 year incidence of the primary endpoint (cardiovascular death, myocardial infarction, stroke, or bleeding ≥ grade 2 according to Bleeding Academic Research Consortium criteria) was significantly lower in guided de-escalation vs. control group [5.9% vs. 8.3%; hazard ratio (HR) 0.70, 95% confidence interval (CI) 0.51-0.96; P = 0.03, number needed to treat = 42]. In elderly patients (age >70, n = 370), the absolute risk of events was higher without significant differences between guided de-escalation vs. control group (15.5% vs. 13.6%; HR 1.17, 95% CI 0.69-2.01; P = 0.56). When the impact of age, as a continuous variable, was analysed on outcomes after guided de-escalation vs. control treatment, an increasing relative risk reduction was observed in the primary endpoint by decreasing age (P_int = 0.02), due to significant reductions in bleeding. Conclusion Treatment effects of guided de-escalation for P2Y₁₂ inhibitors depend on patient's age with younger patients deriving a significant net clinical benefit. Although the safety and efficacy of guided de-escalation in the elderly was similar to uniform prasugrel therapy, this should be further investigated due to the limited sample size of this group.