The effect of empagliflozin on peripheral microvascular dysfunction in patients with heart failure with preserved ejection fraction.

BACKGROUND: Empagliflozin is an effective treatment for heart failure with preserved ejection fraction (HFpEF), but its definite mechanism of action is unclear. Systemic microvascular dysfunction strongly relates to HFpEF aetiology, and we hypothesised that empagliflozin improves microvascular function in HFpEF. OBJECTIVE: To investigate the effect of the sodium-glucose cotransporter-2 inhibitor empagliflozin on peripheral microvascular function in HFpEF. METHODS: This is a pre-post intervention study in patients diagnosed with HFpEF who are eligible for treatment with empagliflozin. Microvascular function assessment using laser speckle contrast analysis of the dorsal forearm during iontophoresis of vasoactive stimuli (acetylcholine, insulin sodium nitroprusside) was performed at baseline and after 3 months of empagliflozin treatment (10 mg daily). The primary outcome was the difference in blood flow measured in the forearm microvasculature between baseline and at follow-up (cutaneous vascular conductance, CVC). Secondarily we investigated quality-of-life based on the EQ-5D-5 L questionnaire at baseline and follow-up. RESULTS: Twenty six patients finished the study according to protocol (mean age of 74 ± 7 years, 62% female). We observed a decreased blood flow response to acetylcholine after 3 months of empagliflozin (CVC: 0.77 ± 0.24 vs. 0.64 ± 0.20, p < 0.001). In contrast, the response to insulin improved (CVC: 0.61 ± 0.43 vs. 0.81 ± 0.32, p = 0.03), and the response to sodium nitroprusside remained stable after 3 months. No significant correlations were found between the changes in blood flow and quality of life. CONCLUSION: This study shows that three months treatment with empagliflozin changed peripheral microvascular function in patients with HFpEF. Empagliflozin may enhance microvascular blood flow specifically via vascular actions of insulin, rather than a general effect on endothelial vasoregulation or smooth muscle cell function. As such, systemic microvascular dysfunction can be a modifiable factor in patients with HFpEF, while the clinical implications thereof warrant further investigations. TRIAL REGISTRATION: The trial was preregistered at clinicaltrials.gov (NCT06046612).