Coronary Microvascular Dysfunction in Hemodialysis-Dependent End-Stage Renal Disease: Prevalence, Characteristics, and Prognostic Implications.

BACKGROUND: Coronary microvascular dysfunction (CMD) is an established mechanism in cardiovascular diseases and is associated with adverse outcomes. However, CMD in hemodialysis (HD) patients remains poorly characterized. This study evaluated the prevalence, physiological profiles, and prognostic implications of CMD in this high-risk population. METHODS AND RESULTS: Among 894 patients who underwent intracoronary physiological assessment of the left anterior descending artery, 87 were on HD. A control group of 87 non-HD patients was selected using propensity score matching for established CMD risk factors. Microvascular resistance reserve (MRR) and the baseline index of microvascular resistance (b-IMR) and hyperemic IMR were compared. MRR was significantly lower in HD than non-HD patients (median [interquartile range (IQR)] 2.4 [1.9-3.4] vs. 3.8 [2.6-5.0], P<0.001). This was driven primarily by lower b-IMR in the HD than non-HD group (median [IQR] 42.3 [23.6-61.0] vs. 68.7 [42.7-90.9], P<0.001); IMR was comparable between the 2 groups (18.6 [12.0-24.7] vs. 18.3 [12.7-26.0], respectively; P=0.65). In HD patients, an MRR of 2.1 was optimal for predicting the composite endpoint (all-cause mortality, heart failure, and acute myocardial infarction). Kaplan-Meier analysis showed event-free survival was significantly worse in HD patients with MRR <2.1 (log-rank P=0.001). CONCLUSIONS: CMD is highly prevalent in HD patients and is characterized by markedly reduced b-IMR. In this population, MRR serves as a potent prognostic indicator.