Exercise gas exchange and echo-derived analysis in HFpEF based on patterns of oxygen peripheral utilization

Abstract

Abstract Background Exercise limitation is a key signature of heart failure with preserved ejection fraction (HFpEF) syndrome evolution with studies highlighting a significant cardiac reserve limitation and others identifying a predominant limit in the peripheral VO2 kinetics and utilization. Aims To clarify the cardiopulmonary and hemodynamic response in HFpEF according to the high or low peripheral O2 utilization patterns during maximal exercise. Materials and Method 38 patients with a HFpEF diagnosis based on the ESC HFpEFF criteria underwent cardiopulmonary exercise test (CPET) combined with stress echocardiography. Patients were divided in two groups according to the median peak c(A-V) O2 difference (Group 1: < 11 mL/dL and Group 2: > 11 mL/dL). Cardiac output (CO) was calculated by echocardiography according to the formula LVOT velocity integral x LVOT area. Data were obtained after a familiarization CPET session. Results Group 1 and 2 presented similar rest demographic, left and right hemodynamic data (table). The relationship between CO and c (A-V) O2 in terms of VO2 isopleths at peak exercise were not related to any difference in CO (figure) Conclusions In HFpEF, an impairment in O2 utilization during exercise appears independent of the cardiac reserve response (similar peak CO increase) but rather peripheral mechanisms implicated in O2 diffusion/release seem to play a dominant role, emerging as selective therapeutic targets for improving functional capacity and symptoms.