A pilot clinical study of adjunctive therapy with selective intracoronary hypothermia in patients with ST-segment elevation myocardial infarction.

OBJECTIVES: We aimed to assess the effect of selective intracoronary hypothermia on outcomes in patients with ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PPCI). BACKGROUND: Intracoronary hypothermia, the feasibility and safety of which has been validated in humans, induced by selective trans-coronary infusion of saline at different temperatures can reduce infarct size (IS) prior to reperfusion in animal models of STEMI. METHODS: Sixty STEMI patients presenting with thrombolysis in myocardial infarction (TIMI) flow grade 0/1 were randomized after coronary artery angiography. Intracoronary hypothermia was induced by selective trans-coronary infusion of saline at 4°C to the endangered myocardium in the 30 patients. The primary endpoint, absolute IS expressed as IS/myocardium at risk (MaR), was assessed by cardiac magnetic resonance imaging at day 7 post-PPCI in 50 patients. Clinical follow-up was undertaken at day 30 after procedure. RESULTS: Intracoronary hypothermia was successfully performed in hypothermia group, without increase in arrhythmia or hemodynamic instability. The mean temperature reduction of 5.8 ± 1.1°C in distal coronary artery was achieved before reperfusion. Mean IS/MaR was predominantly reduced in the hypothermia group (44.85 ± 5.89% vs. 50.69 ± 10.75%, P = 0.022), especially in the anterior STEMI subgroup (46.12 ± 7.54% vs. 55.27 ± 11.175%, P = 0.023). The clinical events appeared no statistical difference between the two groups at the 30-day follow-up. CONCLUSION: The statistical difference in IS/MaR by intracoronary hypothermia as adjunctive therapy to PPCI is an important observation and warrants a larger pivotal trial fully powered for efficacy.