Dual Antiplatelet Therapy with 3rd Generation P2Y12 Inhibitors in STEMI Patients: Impact of Body Mass Index on Loading Dose–Response

Purpose: This study aims to assess the association between body mass index (BMI) and platelet reactivity in STEMI patients treated with oral 3rd generation P2Y12 inhibitors. Methods: Overall, 429 STEMI patients were enrolled in this study. Patients were divided into two groups according to BMI (BMI < 25 vs ≥ 25 kg/m2). A propensity score matching (1:1) was performed to balance potential confounders in patient baseline characteristics. Platelet reactivity was assessed by VerifyNow at baseline and after 3rd generation P2Y12 inhibitor (ticagrelor or prasugrel) loading dose (LD). Blood samples were obtained at baseline (T0), 1 h (T1), 2 h (T2), 4–6 h (T3), and 8–12 h (T4) after the LD. High on-treatment platelet reactivity (HTPR) was defined as a platelet reactivity unit value ≥ 208 units. Results: After propensity score matching, patients with BMI ≥ 25 had similar values of baseline platelet reactivity, while they had higher level of platelet reactivity at 1 and 2 h after the LD and higher rate of HRPT. Furthermore, multivariate analysis demonstrated that BMI ≥ 25 was an independent predictor of HTPR at 2 h (OR 2.01, p =.009). Conversely, starting from 4 h after the LD, platelet reactivity values and HRPT rates were comparable among the two study groups. Conclusions: A BMI ≥ 25 kg/m2 is associated with delayed pharmacodynamic response to oral 3rd generation P2Y12 inhibitor LD, and it is a strong predictor of HTPR in STEMI patients treated by dual antiplatelet therapy with ticagrelor or prasugrel.