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Local myocardial hypothermia induced by transcoronary infusion of saline at different temperatures can reduce infarct size prior to reperfusion therapy as has been demonstrated in animal models. The feasibility and safety of regional hypothermia conducted using intracoronary infusion of room temperature saline has been confirmed in humans. In this study, we assessed the effect of local myocardial hypothermia as adjuvant therapy to primary percutaneous coronary intervention (PPCI) on outcomes in patients with ST-elevation myocardial infarctions (STEMI).
Fifty patients presenting with STEMI within 6 hours of symptom onset and scheduled to undergo PPCI were randomized to this single center, prospective, randomized controlled study. Local hypothermia was induced by continuous infusion of saline to the infarct-related area at 4 °C in the 25 patients constituting the treatment group; and the mean temperature of regional myocardial tissue reached 33.4±0.6°Cat the first episode of balloon inflation. At day 7 post PPCI, infarct size, left ventricular mass and myocardium at risk were measured by the 3.0 Tesla cardiac magnetic resonance imaging method. Our clinical trial was registered in clinicaltrials.gov (NCT03015155).
The emergency revascularization procedure was performed in all of the enrolled patients without statistical delaying in door-to-balloon times (116.04±30.103 minutes versus 111.60±42.076 minutes, hypothermia versus control, P=0.67). Local hypothermia caused 12% reduction in infarct size normalized to myocardium at risk (44.85±5.894% versus 50.69±10.752%, P=0.022), especially in anterior STEMI subgroup. The clinical endpoints, including cardiac death, stroke, major bleeding, heart failure, re-infarction, stent thrombosis, target vessel revascularization, cardiogenic shock and repeat PCI, did not differ significantly between the two groups at the 30-day follow-up.
As an adjunctive therapy to PPCI, local hypothermia was associated with a reduction in infarct size without improving the clinical endpoints during the follow-up period.
CORONARY: Acute Myocardial Infarction