Sonothrombolysis before and after percutaneous coronary intervention provides the largest myocardial salvage in ST-segment Elevation Myocardial Infarction.

BACKGROUND:Sonothrombolysis is a therapeutic application of ultrasound with ultrasound contrast for patients with ST elevation Myocardial Infarction (STEMI). Recent trials demonstrated that sonothrombolysis, delivered before and after primary percutaneous coronary intervention (pPCI), increase infarct vessel patency, improve microvascular flow, reduce infarct size, and improve ejection fraction. However, it is unclear whether pre-pPCI sonothrombolysis is essential for therapeutic benefit. We designed a parallel three-arm sham-controlled randomised controlled trial to address this. METHODS:Patients presenting with first STEMI undergoing pPCI within six hours of symptom onset were randomised 1:1:1 into three arms: sonothrombolysis pre/post pPCI (Group 1), Sham pre & sonothrombolysis post pPCI (Group 2), and Sham pre/post pPCI (Group 3). Our primary endpoint was infarct size (% LV mass) assessed by Cardiac MRI at day 4±2. Secondary endpoints included myocardial salvage index (MSI) and echocardiographic parameters at Day 4±2 and six months. RESULTS:Our trial was ceased early due to the COVID pandemic. From 122 patients screened between September 2020 and June 2021, 51 patients (Age 60, male 82%) were included post randomisation. Median sonothrombolysis took 5 minutes pre pPCI and 15 minutes post, without significant door-to-balloon delay. There was a trend towards reduction in median infarct size between Group 1 (8%[IQR 4,11]), Group 2 (11%[7,19]) or Group 3 (15%[9,22]). Similarly there was a trend towards improved MSI in Group 1 (79%[64,85]) compared to Groups 2 (51%[45,70]) and 3 (48%[37,73]) No major adverse cardiac events occurred during hospitalization. CONCLUSION:Pre-pPCI sonothrombolysis may be key to improving MSI in STEMI. Multicentre trials and health economic analyses are required before clinical translation.