Clinical outcomes of angina treatment in coronary microvascular dysfunction: results of a multicenter observational study

Background Coronary microvascular dysfunction (CMD or CMVD), a major subtype of angina with non-obstructive coronary arteries, affects a substantial proportion of patients and represents an important unmet clinical need, particularly in China. Studies evaluating comparative treatment efficacy in angina populations, especially across CMVD and non-CMVD, remain limited. Objective To assess the efficacy of different therapeutic regimens (nicorandil vs. non-nicorandil treatment) among angina pectoris patients with CMVD. Methods We conducted a retrospective analysis of baseline and follow-up data from nine centres of the GREAT study, including patients with angina from nine hospitals in China treated with nicorandil or non-nicorandil regimens. Patients with and without CMVD (coronary angiography-derived index of microvascular resistance [caIMR], ≥25 vs. < 25) were included, and post-treatment differences in Seattle Angina Questionnaire (SAQ) scores were compared between groups. Results A total of 1,259 patients with angina were included in this study. Among them, 429 patients had CMVD (caIMR ≥25), comprising 170 in the nicorandil group and 259 in the non-nicorandil group, while 830 patients did not have CMVD (nicorandil group, 319; non-nicorandil group, 511). After propensity score matching, the mean SAQ summary score (SAQ-SS) improvement in patients with CMVD, was greater in the nicorandil group than in the non-nicorandil group (mean change: 16.80 vs. 12.60, P = 0.044). Among patients without CMVD, nicorandil therapy resulted in significantly greater SAQ-SS improvement at respective timepoints (3 months: 15.68 vs. 12.15, P = 0.005; 6 months: 18.70 vs. 14.44, P < 0.001; 9 months: 18.11 vs. 15.07, P = 0.008). Conclusion Nicorandil-based regimens may be associated with greater improvement in health status among angina patients with CMVD compared with non-nicorandil treatments.