Baseline platelet reactivity in acute myocardial infarction treated with primary angioplasty - Influence on myocardial reperfusion, left ventricular performance, and clinical events

Background Platelet reactivity is believed to play a key role in the pathophysiology of ST-segment elevation myocardial infarction (STEMI). We sought to determine whether platelet reactivity predicts impaired myocardial reperfusion, left ventricular (LV) dysfunction, and clinical events in an unselected group of patients with STEMI. Methods Platelet reactivity was measured before primary angioplasty in 125 consecutive patients with the use of Platelet Function Analyzer-100. Six-month follow-up was performed. Results Patients were stratified into 4 quartiles according to the collagen adenosine diphosphate closure time (CADP-CT), with the fourth quartile (CADP-CT <= 55 seconds; n = 32) defined as high reactivity. There was an increasing rate of diabetes across quartiles: 6% in the first and 38% in fourth (P <.0001). Myocardial Blush Grade 0 or I and the absence of ST-segment resolution (:5,50%) were observed more often in the fourth quartile than in quartiles I through 3 (84% vs 22%, 27%, 35% and 81 % vs 16%, 17%, 26%, respectively,- P <.000 1 for all). In logistic regression, high reactivity was an independent predictor of Myocardial Blush Grade 0 or I (odds ratio [OR], 22.7; 95% confidence interval [CI], 6.5-7M; P <.0001), ST-segment resolution -,50% (OR, 28.6; 95% Cl, 8.6-95.2; P <.0001), LV remodeling (OR, 10.4; 95% Cl, 3.3-32.7; P <.0001), lack of early (OR, 7.9; 95% Cl, 2.8-22.3; P <.0001) and late LV functional recovery (OR, 7.3; 95% Cl, 2.9-18.8; P <.0001), and clinical events (OR, 7.8; 95% Cl, 2.5-24.9; P =.0005). Conclusions Platelet reactivity is an independent predictor of myocardial reperfusion. Moreover, CADP-CT being a marker of myocardial reflow may also provide early prognostic information concerning LV performance and adverse clinical events after STEMI.