Sonothrombolysis in Patients with ST-elevation Myocardial Infarction with Electrocardiographic No-Reflow after Percutaneous Coronary Intervention: a Randomized Controlled Trial.

BACKGROUND AND AIMS:Approximately 50% of patients with ST-elevation myocardial infarction (STEMI) treated with percutaneous coronary intervention (PCI) suffer from microvascular no-reflow. Pre- and post-PCI sonothrombolysis has shown to decrease infarct size and improve left ventricular (LV) systolic function in STEMI patients receiving urgent PCI. The aim of this study was to investigate whether post-PCI sonothrombolysis alone in STEMI patients with persistent ST-elevation could reduce no-reflow and infarct size. METHODS:STEMI patients with symptoms <12 hours, who had persistent ST-elevation (≤70% ST-resolution) after primary PCI. were randomized to sonothrombolysis or control. The primary endpoint was summed (Σ) ST-elevation 60 minutes after study intervention. Secondary endpoints included infarct size, myocardial perfusion score, LV ejection fraction on cardiovascular magnetic resonance (CMR) imaging at two months follow up, and clinical outcome at six months follow up. RESULTS:67 STEMI patients with persistent ST-elevation after PCI were randomized (49 left anterior descending, 18 right coronary/left circumflex artery). No difference was observed in Σ ST-elevation 60 minutes after study intervention (mean difference: 0.6mm, 95% CI: -1.1 - 2.2, p=0.50). Complete ST-resolution occurred in 14 (40%) of patients treated with sonothrombolysis compared to six (19%) of controls (p=0.16). Myocardial perfusion score index (1.5 ±0.3 vs. 1.5 ±0.3, p=0.93), infarct size (18.0±10% vs. 16.8±11%; p=0.29) or LV ejection fraction on CMR (46±8% vs.47±11% in the control group; p=0.86) were comparable. Incidence of all-cause death, acute coronary syndrome and hospital admission for heart failure at six months follow up was similar between the groups (sonothrombolysis: 2, control: 5). CONCLUSION:In STEMI patients with persistent ST-elevation after PCI, post-PCI sonothrombolysis did not result in more ST-resolution or smaller infarct size compared to control subjects. The incidence of the combined clinical endpoints was remarkably low in this high-risk patient population.