Prevalence and importance of coronary microvascular dysfunction in patients with heart failure and reduced or mildly reduced ejection fraction.

Abstract

Aims: We investigated the prevalence of coronary microvascular dysfunction (CMD) and its association with severity of heart failure in patients with reduced or mildly reduced ejection fraction (HFrEF and HFmrEF).

Method: Patients with stable, symptomatic heart failure with left ventricular ejection fraction (LVEF) <50% were enrolled. Data collection included physical examination, blood samples, Kansas City Cardiomyopathy Questionnaire (KCCQ), carotid to femoral pulse wave velocity, echocardiography and adenosine-based transthoracic Doppler echocardiography to assess coronary flow reserve (CFR). A CFR <2.5 was used to diagnose CMD. Adjusted multivariable linear regression analysis with CFR as the dependent variable and adjusted multivariate logistic regression with CMD as the dependent variable were performed.

Results: A total of 125 patients were included, of whom 99 (79%) were men. The overall mean age is 73.4 (±7.5) years. In patients eligible for CFR (n=68, 54%), CMD was present in 45 (66%). Patients with CMD had higher N-terminal pro B-type natriuretic peptide (NTproBNP), hsTroponin-T, lower KCCQ score, lower left and right ventricular and left atrial global longitudinal strain (GLS) (p<0.05). In multivariable linear regression, lower CFR was independently associated with reduced GLS, higher NTproBNP and hsTroponin-T. Furthermore, in adjusted logistic regression analysis, lower LVEF, reduced right ventricular GLS and higher biomarkers were independently associated with an increased risk of CMD.

Conclusion: CMD was present in 66% of patients with chronic heart failure and HFrEF or HFmrEF. Markers of more severe heart failure, including reduced GLS and higher NTproBNP and hsTroponin-T, were independently associated with lower CFR. Reduced right ventricular GLS and higher levels of the biomarkers were also independently associated with CMD.