[Evaluation of coronary and peripheral microvascular endothelial dysfunction in patients with heart failure with non-reduced ejection fraction].

<b>Objective:</b> To evaluate the prevalence, potential risk factors, and correlation between coronary and peripheral microvascular dysfunction in heart failure with non-reduced ejection fraction (nHFrEF) patients. <b>Methods:</b> This was a prospective registry study. nHFrEF patients admitted to Zhongshan Hospital affiliated with Fudan University from December 2021 to December 2023 were enrolled. According to coronary flow reserve (CFR) or reactive congestion index (RHI), enrolled patients were divided into coronary microvascular endothelial dysfunction (CMD) group (CFR<2.5) and no CMD group (CFR≥2.5) or peripheral microvascular endothelial dysfunction (MED) group (RHI<1.67) and no MED group (RHI≥1.67). Patients' general information, laboratory and auxiliary examination data were collected. Univariate and multivariate logistic regression were used to analyze the influencing factors of CMD and MED in nHFrEF patients, and Spearman correlation analysis was used to evaluate the correlation between MED and CMD. <b>Results:</b> A total of 142 nHFrEF patients were enrolled, aged 69.0 (59.0, 74.0) years, with a male proportion of 66.9% (95/142). The grouping results were as follows: (1) According to CFR, there were 73 cases in the CMD group and 69 cases in the no CMD group; (2) According to RHI, there were 57 cases in the MED group and 85 cases in the no MED group. The prevalence of CMD and MED in this study was 51.4% (73/142) and 40.1% (57/142), respectively. Univariate logistic regression analysis showed that increased heart rate, chronic kidney disease, atrial fibrillation, elevated N-terminal pro-B type natriuretic peptide levels, and increased urinary albumin/creatinine ratio were risk factors for CMD, while increased RHI was a protective factor for CMD; Atrial fibrillation is a risk factor for MED, while increased CFR is a protective factor for MED. Incorporating clinically significant variables from univariate analysis into multivariate analysis, the results showed that increased heart rate and elevated RHI remained risk and protective factors for CMD, respectively; increased CFR remains a protective factor for MED. Spearman correlation analysis showed that CFR was negatively correlated with lg urinary albumin/creatinine ratio, lg cardiac troponin T, lg N-terminal pro-B type natriuretic peptide, and heart rate; RHI is positively correlated with CFR. <b>Conclusions:</b> The prevalence of CMD and MED in nHFrEF patients is high, and the two have a certain positive correlation. Increased heart rate and RHI are risk and protective factors for CMD, respectively, while increased CFR is a protective factor for MED. MED may be a potential therapeutic target for nHFrEF patients.