Myocardial blood flow reserve is impaired in patients with aortic valve calcification and unobstructed epicardial coronary arteries

Abstract

Introduction: Although coronary atherosclerosis is associated with calcific aortic valve disease (CAVD), it is not known whether they share pathophysiological mechanisms in early disease. Aims: To investigate the relationship between myocardial blood flow reserve (MBFR) - a measure of coronary microcirculatory function, and early CAVD. We also determined whether this relationship was independent of coronary artery disease (CAD) and hs-CRP, a marker of systemic inflammation. Methods&Results: 183 patients with chest pain and unobstructed coronary arteries were recruited. AVCS, coronary total plaque length (TPL), and coronary calcium score were quantified from multislice CT. MBFR was assessed using vasodilator myocardial contrast echocardiography. Inflammatory markers were obtained from venous sampling. Mean age was 59.8 years, with 52.5% being male. The mean AVCS was 68AU (SD 258). Mean TPL was 15.6mm, and median coronary calcification score was 43.5AU. The mean MBFR was 2.20 (SD 0.52). Mean hs-CRP was 2.52mg/L (SD 3.86), with 59% participants having normal hs-CRP levels. Multivariate linear regression modelling incorporating demographics, coronary plaque characteristics, MBFR, and inflammatory markers, demonstrated that age (-=+0.05, CI:+0.02,+0.08, P=0.007), hs-CRP (-=+0.09, CI:+0.02,+0.16, P=0.010) and presence of diabetes (-=+1.03, CI:+0.08,+1.98, P=0.033), were positively associated with AVCS. In contrast, MBFR (-=-0.87, CI:-1.44,-0.30, P=0.003), body mass index (-=-0.11, CI:-0.21,-0.01, P=0.033), and LDL cholesterol (-=-0.32, CI:-0.61,-0.03, P=0.029) were negatively associated with AVCS. TPL and coronary calcium score became insignificant when included in multivariate analysis. Conclusions: MBFR is an independent predictor of aortic valve calcification and this effect is independent of the presence of CAD and also systemic inflammation.<br />