High mechanical index three-dimensional ultrasound combined with microbubbles in improving myocardial reperfusion

Objective: To observe the feasibility of improving thrombolytic effect and ischemic myocardial microperfusion by transthoracic high mechanical index (MI) three-dimensional ultrasound combining with microbubbles. Methods: Fifteen left anterior descending artery occluded pigs were assigned into experimental group (n=8) and control group (n=7). In experimental group, transthorocic high MI three-dimensional ultrasound was applied to precordial chest wall for 30 min with microbubbles infusion after tissue-type plasminogen activator (tPA) administration, while pigs in control group received no transthorocic high MI three-dimensional ultrasound. Recanalization rate of the coronaries 90 min after treatment were compared. Wall thickening of the risk areas, size of risk areas at 90 min after treatment, and ST segment resolution of ECG at 30, 60 and 90 min were compared with baseline in both groups. Results: Significant improvement of wall thickening after treatment were achieved in experimental group, though there was no significant difference of epicardial recanalization rates in both groups at 90 min. Significant ST segment resolution of ECG was observed at 30, 60, 90 min after treatment in experimental group, which were absence until 90 min after treatment in control group. There was significant reduction in the size of risk areas 90 min after treatment, even for those without epicardial recanalization in experimental group. Conclusion: Combined with microbubbles, transthorocic high MI three-dimensional ultrasound has potential ability to improve myocardial reperfusion of the occluded coronary, even without epicardial recanalization in left anterior descending artery occluded pig models.