Digital thermal monitoring of reactive hyperemia: potential mechanisms and clinical relevance among patients with heart failure with reduced ejection fraction
Am J Physiol Heart Circ Physiol 2026 Apr 1;330(4):H1235-H1238.
doi: 10.1152/ajpheart.00980.2025.Epub 2025 Dec 31.
INTRODUCTION
Chronic heart failure involves functional and structural impairment of ventricular filling or ejection of blood from the ventricles, with ∼50% of cases being heart failure with reduced ejection fraction (HFrEF) (1). Systemic vascular dysfunction has been identified as a key factor in the pathogenesis and progression of HFrEF (1). Endothelial cells, which line the arterial lumen, regulate vascular tone through the synthesis and release of endothelial-derived vasoactive substances, such as the vasodilator nitric oxide (NO), among other vasoactive substances (2). Previous work has reported that HFrEF promotes endothelial cell dysfunction due to increased synthesis of reactive oxygen species and decreased NO bioavailability (2). In this journal, Charfeddine et al. (3) sought to determine whether 3 mo of optimal pharmacological treatment for HFrEF improved endothelial function as assessed by digital thermal monitoring among patients with HFrEF. This longitudinal, prospective study included 120 patients over the age of 18 yr who had previously been diagnosed with HFrEF. Endothelial function, echography, and impedance cardiography were conducted at baseline and after 3 mo of pharmacological therapy as per current guidelines. The pharmacological treatment included renin-angiotensin-aldosterone system inhibitors (e.g., angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers, and angiotensin receptor-neprilysin inhibitors), as well as β-blockers, aldosterone antagonists, and sodium-glucose cotransporter 2 inhibitors (3). Endothelial function was measured using digital-thermal monitoring, in which temperature increases in the index finger were measured in comparison with the contralateral limb following a period of proximal cuff-induced reactive hyperemia. These temperature increases were used to quantify endothelial function via the endothelium quality index (EQI). Participants were monitored for a year after testing to examine the relationship between endothelial function and major cardiac events, rehospitalization, and cardiovascular-related deaths. Charfeddine et al. (3) report an improvement in EQI following 3 mo of optimal treatment, with multivariate analyses highlighting that an angiotensin receptor-neprilysin inhibitor, β-blockers, and quadruple therapy were predictors for improved EQI. Increased EQI was associated with increased left ventricle ejection fraction and cardiac output but decreased vascular resistance (3). Improved EQI was associated with reduced mortality and rehospitalization (3). Overall, this study provides evidence that digital thermal monitoring of reactive hyperemia demonstrates clinical relevance among a population of people with HFrEF, and that current pharmacological guidelines are effective in improving such responses.
Comments