Insulin resistance and exercise tolerance in heart failure patients: linkage to coronary flow reserve and peripheral vascular function

摘要

Background Insulin resistance has been linked to exercise intolerance in heart failure patients. The aim of this study was to assess the potential role of coronary flow reserve (CFR), endothelial function and arterial stiffness in explaining this linkage. Methods 39 patients with LVEF?2peak), digital measurement of endothelial function and arterial stiffness (augmentation index), dual X-ray absorptiometry scan (DEXA) for body composition and insulin sensitivity by a 2?hr hyperinsulinemic (40?mU/min/m2) isoglycemic clamp. Results Fat free mass adjusted insulin sensitivity was significantly correlated to VO₂peak (r?=?0.43, p?=?0.007). Median CFR was 1.77 (IQ 1.26-2.42) and was correlated to insulin sensitivity (r 0.43, p?=?0.008). CFR (r?=?0.48, p?=?0.002), and arterial stiffness (r?=??0.35, p?=?0.04) were correlated to VO₂peak whereas endothelial function and LVEF were not (all p?>?0.15). In multivariable linear regression adjusting for age, CFR remained independently associated with VO2peak (standardized coefficient (SC) 1.98, p?=?0.05) whereas insulin sensitivity (SC 1.75, p?=?0.09) and arterial stiffness (SC ?1.17, p?=?0.29) were no longer associated with VO2peak. Conclusions The study confirms that insulin resistance is associated with exercise intolerance in heart failure patients and suggests that this is partly through reduced CFR. This is the first study to our knowledge that shows an association between CFR and exercise capacity in heart failure patients and links the relationship between insulin resistance and exercise capacity to CFR.