Background: Microbubble-mediated sonothrombolysis has been shown to improvevascular and microvascular thrombotic obstruction. Initial results in ST elevation myocardial infarction (STEMI) seem promising.
Hypothesis: We hypothesized that early application of diagnostic ultrasound (DUS) high mechanical index (MI) during microbubble infusion would augment epicardial and microvascular flow when integrated with the emergent management of acute STEMI with percutaneous coronary intervention (PCI).
Methods: 57 patients (44 males; 59±10 years) with STEMI underwent DUS and microbubbles (3% Definity®). Patients were randomized to either DUS with intermittent high MI impulses (1.2) when microbubbles were visualized within the risk area (therapy group, n=32) or low MI imaging (control group, n=25). The therapy group received sonothrombolysis prior and after PCI. Comparisons between groups were coronary recanalization rate at initial angiography, left ventricular ejection fraction (LVEF), wall motion score index (WMSI) and microvascular perfusion index (MPI) at baseline, 48 h and 30 days.
Results: Angiographic recanalization prior to PCI was 56% in the therapy versus 12% in control group (p<0.001). At baseline, there was no difference between groups in LVEF, WMSI and MPI (Figure). The mean number of segments with persistent microvascular perfusion defects was similar in therapy (7.9±3.3) and control (9.0±2.7);p=0.19. At 48 hours, LVEF was higher in therapy than control while WMSI was lower in therapy than control group. The number of segments with persistent microvascular defects was lower in therapy than control group (6.3±3.5 vs 8.5±3.0;p=0.01). These parameters were maintained at 30 days.
Conclusions: Microbubble-mediated sonothrombolysis with DUS increases both the rate of epicardial recanalization and microvascular perfusion in patients with acute STEMI, resulting in improvement in left ventricular systolic function and myocardial perfusion.