Background: Sacubitril/valsartan has been shown to reduce hospital admissions and even mortality for heart failure. In heart failure and acute coronary syndrome, the effects of sacubitril/valsartan have been studied, but the effect on coronary artery flow is not known.

Objective: We aimed to understand the effect of sacubitril/valsartan on coronary artery flow by using echocardiographic coronary flow reserve (CFR).

Methods: Thirty-six patients (17 ischemic and 19 non-ischemic) with heart failure with reduced ejection fraction (EF of < 40%) eligible for sacubitril/valsartan treatment and 21 normal controls were recruited. The study group and controls were similar with regard to gender, smoking status, and age distribution (p = 0.874, p = 0.709, and p = 0.765, respectively). Blood pressure, heart rate, 6-minute walk test (6MWT), N terminal pro B type natriuretic peptide (NT-pro-BNP) level, standard echocardiography, from where left anterior descending mid-distal flow was seen, baseline peak diastolic flow rate and 2 minutes after dipyridamole infusion, and hyperemic peak diastolic flow rate were measured, and CFR with echocardiography was assessed prior to and at 6 months after sacubitril/valsartan initiation.

Results: Baseline peak diastolic flow rate did not exhibit a significant difference at 6 months (p = 0.143), but hyperemic peak diastolic flow rate, CFR, EF (%), and 6MWD values were significantly increased (all p < 0.001), and New York Heart Association Functional Class, NT-pro-BNP (pg/mL), left ventricule end diastolic diameter (mm), and left ventricule end systolic diameter (mm) values were significantly decreased (all p < 0.001) after sacubitril/valsartan treatment.

Conclusions: Sacubitril/valsartan significantly alters coronary blood flow, especially its dynamic features, in patients with heart failure with reduced ejection fraction.