The impact of therapeutic hypothermia on on-treatment platelet reactivity and clinical outcome in cardiogenic shock patients undergoing primary PCI for acute myocardial infarction: Results from the ISAR-SHOCK registry.

INTRODUCTION: Mild therapeutic hypothermia (TH) is standard of care after cardiac arrest of any cause. However, its impact on on-treatment platelet reactivity and clinical outcome in patients with acute myocardial infarction (AMI) complicated by cardiogenic shock and undergoing PCI with P2Y12 receptor inhibitor treatment is less clear. METHODS AND
RESULTS: For the ISAR-SHOCK registry, 145 patients with AMI, cardiogenic shock and primary PCI in two centers (Deutsches Herzzentrum München and Klinikum rechts der Isar, Technical University Munich) between January 2009-May 2012 were analysed. Of these, 64 (44%) patients received TH treatment. The median [IQR] ADP-induced platelet aggregation following thienopyridine loading dose administration (clopidogrel in 95 and prasugrel in 50 patients) did not differ between the two groups (419 [283-684] for TH vs. 355 [207-710] AU x min for non-TH patients, P=0.22). After 30days follow-up, no significant differences were observed between both groups for mortality (42 vs. 44 %, HR: 0.93, 95% CI [0.56-1.53], p=0.77), MI (6 vs. 6%, HR: 0.99 95% CI [0.27-3.7], p=0.99) and TIMI minor bleedings (17 vs. 17%, HR 0.99 95% CI [0.45-2.18], p=0.98). TIMI major bleedings were numerically higher in the TH vs. non-TH cohort (25 % vs. 12 %, HR: 2.1 95% CI [0.95-4.63], p=0.07). Three definite stent thrombosis (ST) were observed in this registry and all STs occurred in the TH group of patients (p=0.09).
CONCLUSION: Results of this registry suggest that TH does not negatively impact on platelet reactivity in shock patients receiving either clopidogrel or prasugrel. The numerically higher rate of major bleedings and the clustering of STs in the TH cohort warrant further investigation.