Antiplatelet effect of prasugrel and clopidogrel in hypothermic patients after cardiac arrest for acute myocardial infarction
Abstract
Therapeutic hypothermia (TH) is recommended after out-of-hospital cardiac arrest (OHCA). Acute myocardial infarction (AMI) is one of the most common causes of OHCA and survivors receive P2Y12 inhibitors after PCI.
TH can attenuate the effectiveness of drugs, but the effect of TH on efficacy of P2Y12 inhibitors is unknown. The aim of this study was to compare platelet inhibitory effects of prasugrel and clopidogrel in patients with AMI treated by TH.
Methods: The total of 53 patients after OHCA for AMI were enrolled in a single center, prospective, observational study. The subgroup of 24 pts. who underwent PCI, receive P2Y 12 inhibitors, underwent TH and survived more than 3 days was analyzed.
Group A (n=12 pts.) receive clopidogrel (LD 600mg + MD 150mg daily) and group B (n=12 pts.) receive prasugrel (LD 60mg + MD 5/10mg daily). Platelet reactivity index (PRI-VASP) was measured on days 1, 2 and 3.
A PRI-VASP under 50% is defined as effective platelet inhibition. Results: Median values in the clopidogrel group showed significantly higher PRI-VASP compared to the prasugrel group (79% vs. 25% on day 1; 81% vs. 17% on day 2; 76% vs. 19% on day 3; p< 0.001).
The number of patients with ineffective platelet inhibition (PRI-VASP GREATER-THAN OR EQUAL TO 50%) was in group A vs. B 83% (10/12) vs. 8% (1/12) on days 1 and 2, 83% (10/12) vs. 0% (0/12) on day 3.
Conclusions: Prasugrel, but not clopidogrel, is very effective in terms of therapeutic hypothermia in patients after OHCA for AMI.