Coronary Microcirculatory Dysfunction in Aortic Stenosis: Myocardial Contrast Echocardiography Study

Background. The aims of this study were to quantify the microcirculatory dysfunction in aortic stenosis (AS) and to measure the changes in transmural perfusion after aortic valve replacement (AVR), using quantitative myocardial contrast echocardiography. Methods. Myocardial contrast echocardiography was used to quantify the myocardial blood flow in both the subendocardium and subepicardium in 22 patients with AS (A group), before, 2 weeks after, and 1 year after AVR. Healthy volunteers (C group, n = 10) and patients with mitral regurgitation (M group, n = 10) were included as controls. Triggered myocardial contrast echocardiography was performed, and the endosystolic 1.5 harmonic images were recorded. Results. The myocardial contrast echocardiography study showed that, before AVR, the myocardial blood flow in the subendocardium was significantly lower in the A group than in the other groups (CI = -18.6 +/- 3.0 dB, -11.8 +/- 4.1 dB, and -12.7 +/- 4.1 dB, respectively, in A, M, and C groups; p < 0.05), whereas there was no significant difference in blood flow in the subepicardium. In the A group, the myocardial blood flow in the subendocardium was significantly improved 2 weeks after AVR (-13.1 +/- 3.5 dB after AVR), and this improvement was preserved 1 year after AVR. Conclusions. In patients with AS, the myocardial blood flow in the subendocardium declined preoperatively, and the coronary microcirculatory function was recovered after AVR in both the short and long term.