Abstract
PURPOSE The goal of this study was to investigate the effects of the antianginal drugs ranolazine, nicorandil, and ivabradine on coronary microvascular function. METHODS Electronic scientific databases were searched for randomized trials investigating the effects of antianginal drugs on coronary microvascular function. Primary outcomes were changes in the coronary flow reserve (CFR), index of microvascular resistance (IMR), and myocardial perfusion reserve index (MPRI). The secondary outcome was the Seattle Angina Questionnaire scores. The standardized mean difference or weighted mean difference (WMD) (95% CI) served as a summary statistic. FINDINGS The antianginal drugs ranolazine, nicorandil, and ivabradine did not increase the CFR compared with the control drugs (standardized mean difference, 0.39; 95% CI, -0.08 to 0.85; P = 0.10). Ranolazine did not increase the global MPRI compared with the control drugs (weighted mean difference [WMD], 0.11; 95% CI, -0.06 to 0.29; P = 0.21). However, in the subgroups with a baseline CFR <2.5 or a global MPRI <2, ranolazine increased the global MPRI (WMD, 0.19; 95% CI, 0.10 to 0.27; P < 0.0001). In addition, the subendocardial midventricular MPRI (mid-subendocardial MPRI) was improved after ranolazine treatment (WMD, 0.12; 95% CI, 0.03 to 0.20; P = 0.007). Moreover, nicorandil significantly reduced the IMR compared with the control drugs (WMD, -7.63; 95% CI, -11.82 to -3.44; P = 0.0004). In addition, ranolazine and ivabradine improved 3 of the 5 Seattle Angina Questionnaire scores. IMPLICATIONS Ranolazine improved the global MPRI in patients with definite coronary microvascular dysfunction and the mid-subendocardial MPRI with suspicious coronary microvascular dysfunction, and nicorandil reduced the IMR. In addition, ranolazine and ivabradine reduced angina. Moreover, it is possible that the IMR and mid-subendocardial MPRI are more sensitive than the CFR and global MPRI for evaluating coronary microvascular function.
