Association of Coronary Microvascular Dysfunction With Heart Failure Hospitalizations and Mortality in Heart Failure With Preserved Ejection Fraction: A Follow-up in the PROMIS-HFpEF Study.

Background: Coronary microvascular dysfunction (CMD) is common in heart failure with preserved ejection fraction (HFpEF). We assessed the association of CMD with hospitalization and mortality in HFpEF.

Methods And Results: We assessed the 1-year outcomes in patients from the PROMIS-HFpEF study, a prospective observational study of patients with chronic stable HFpEF undergoing coronary flow reserve measurements. Outcomes were (1) time to cardiovascular (CV) death/first HF hospitalization, (2) CV death/recurrent HF hospitalizations, (3) all-cause death/first HF hospitalization, and (4) first and (5) recurrent all-cause hospitalizations. CMD was defined as coronary flow reserve of <2.5. Time to CV death/first hospitalization was compared by log-rank test and recurrent HF and all-cause hospitalizations by Poisson test. Of 263 patients enrolled, 257 were evaluable at 1 year. Where the coronary flow reserve was interpretable (n = 201), CMD was present in 150 (75%). The median follow-up was 388 days (Q1, Q3 365, 418). The outcome of CV death/first HF hospitalization occurred in 15 patients (4 CV deaths). The incidence rate was in CMD 96 per 1000 person-years, 95% confidence interval 54-159, vs non-CMD 0 per1000 person-years, 95% confidence interval 0-68, P = .023, and remained significant after accounting for selected clinical variables. In patients with CMD, the incidence rates were significantly higher also for CV death/recurrent HF hospitalizations, all-cause death/first HF, and recurrent but not first all-cause hospitalization.

Conclusions: In this exploratory assessment of the prognostic role of CMD in HFpEF, CMD was independently associated with primarily CV- and HF-specific events. The high prevalence of CMD and its CV and HF specific prognostic role suggest CMD may be a potential treatment target in HFpEF.