Changing Reflections of the Coronary Microcirculation After Percutaneous Aortic Valve Replacement

Abstract

In this issue of Circulation , Davies et al1 assess the changes in coronary blood flow and reserve after the relief of aortic stenosis (AS) by percutaneous aortic valve replacement (PAVR) and implicate these findings as additional mechanisms bearing on the critical role of the coronary microcirculation in this population. Article see p 1565 One cannot help but be intrigued by the novel physiological insights that pulsed wave analysis brings to one of the oldest cardiovascular diseases, AS, and one of the newest procedures in interventional cardiology, namely PAVR. For decades, the diagnosis and treatment of AS have rightly focused on identifying and then ameliorating the adverse consequences of abnormal transvalvular pressure and flow. In the absence of coronary artery disease, the mechanisms of angina in AS were debated and attributed mostly to microvascular insufficiency with ischemia resulting from myocardial oxygen supply/demand imbalance. Left ventricular (LV) muscle mass was increased out of proportion to myocardial capillary oxygen supply.2,3 As one might expect in medical science, this is not the end of the story. Examining the arterial pulsed wave dynamics that characterize features of both epicardial and microcirculatory blood flow, Davies et al detail additional mechanisms beyond coronary reserve impairment to better understand why angina may occur in the AS patient with normal coronary arteries. PAVR produced not only a fall in myocardial microvascular resistance, but also improved diastolic filling waves related to favorable changes in LV wall stress as another postulated mechanism for a reduction in …