Impact of hyperhomocysteinemia on coronary microcirculation in patients referred for elective coronary angiography

Hyperhomocysteinemia has been identified as an independent risk factor for cardiovascular diseases. The aim of this study was to investigate the impact of hyperhomocysteinemia on coronary microcirculation in patients who have been referred for elective coronary angiography. This study included 79 consecutive participants who were referred for elective coronary angiography due to suspected myocardial ischemia at The Second Hospital of Wenzhou Medical University from May 2014 to December 2015. The index of microvascular resistance (IMR), coronary flow reserve (CFR), and fractional flow reserve (FFR) were measured in coronary arteries with intermediate stenoses. Blood samples were collected to determine homocysteine and high-sensitivity C-reactive protein (hs-CRP) levels. All participants were categorized into two groups according to the plasma homocysteine cutoff value of 10 μmoI/L. Participants in the high-level homocysteine group had higher IMR and lower FFR during hyperemia compared to participants in the normal-level homocysteine group. Linear regression analysis revealed that homocysteine levels were positively correlated with IMR (r = 0.550, P < 0.01) and negatively correlated with FFR (r = -0.173, P < 0. 01). Serum hs-CRP levels were positively correlated with IMR (r = 0.699, P < 0. 01). Multiple regression analysis indicated that homocysteine was an independent predictor of IMR (beta coefficient, 0.50; 95% confidence interval, 0.16-0.85, P = 0.005). Patients with hyperhomocysteinemia were characterized by elevated hs-CRP serum levels, higher IMR, and lower FFR. Hyperhomocysteinemia may cause coronary microcirculatory dysfunction partly by promoting inflammatory responses involving hs-CRP-related mechanisms.