Reduction of functional cardiovascular reserve in the stages of chronic kidney disease

Abstract

Objective: Patients with chronic kidney disease (CKD) present reduced oxygen consumption at peak exercise (VO2peak). No studies have evaluated objective measures of the cardiovascular reserve, besides VO2peak and VO2at the anaerobic threshold (VO2AT), and compared these measures among ckd patients at different stages of the disease. Methods: Fifty-eight patients [pre-dialysis group (PD)=26, hemodialysis group (HD)=20, and post-kidney transplant group (KT)=12] were included. The following measures of cardiovascular reserve were obtained: 1) peak heart rate (HR); 2) peak systolic blood pressure (SBP); 3) VO2peak and % predicted; 4) VO2AT and % of predicted VO2; 5) peak circulatory power; 6) ventilatory efficiency for the production of carbon dioxide (VE/VCO2 slope); 7) oxygen uptake efficiency slope (OUES); and 8) recovery of gas exchange. Results: The VO2peak and VO2AT in the PD, HD, and KT groups were reduced to 86% and 69%, 70% and 57%, and 79% and 64% of the predicted value, respectively. Patients in the HD group had lower VO2peak (17.5±5.9 vs. 23.2±8.2 [p-value=0.036]) and VO2AT (14.0±5.2 vs. 18.3±4.7 [p-value=0.039]) compared to patients in the KT group. OUES was significantly lower in the HD group compared to the KT group (p-value=0.034). Age in the PD, HD, and KT groups and sedentary lifestyle in the KT group were predictors of VO2peak. Conclusions: CKD patients presented a reduction in cardiovascular reserve regardless of the stage of the disease. However, hemodialysis patients presented a greater reduction of cardiovascular reserve when compared to post-kidney transplant patients.