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

SUMMARY

OBJECTIVE

Patients with chronic kidney disease (CKD) present reduced oxygen consumption at peak exercise (VO₂ peak). No studies have evaluated objective measures of the cardiovascular reserve, besides VO₂ peak and VO₂ at the anaerobic threshold (VO₂ AT), 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) VO₂ peak and % predicted; 4) VO₂ AT 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 VO₂ peak and VO₂ AT 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 VO₂ peak (17.5±5.9 vs. 23.2±8.2 [p-value=0.036]) and VO₂ AT (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 VO₂ peak.

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.

Renal insufficiency, chronic; Exercise test; Kidney transplantation; Renal dialysis