Cardiovascular Responses to Exercise following Renal Transplantation

Abstract

Patients with Chronic Kidney Disease (CKD) treated with dialysis have severely limited exercise capacity and report extremely low levels of physical functioning. Successful renal transplant (RTX) results in significant improvements in VO2peak, however the mechanism of this increase has not been identified. PURPOSE: To measure cardiovascular changes following RTX. METHODS: We tested 6 patients before and 6 months after RTX (4 males/2 females; age 34.1 ± 4 yr) and a group of 8 patients who stayed on hemodialysis (CHD) (7 males; 1 female; age 43.4 ± 11.5 yr) over the same amount of time. Testing included symptom-limited treadmill testing with measurement of VO2peak. Cardiac output (CO) was measured using open circuit acetylene wash-in technique. Arterial blood gases were obtained to determine arterial O2content (CaO2). a-vO2difference, Stroke volume (SV) and total peripheral resistance (TPR) were calculated. Paired t-tests were performed on baseline and 6 month data in each of the groups. Significance was set at p<.05. RESULTS: All subjects achieved respiratory exchange ratios >1.0 and RPE >17. RTX resulted in significant increases in VO2peak, CO, HR and decreased TPR. There were no changes over 6 months in the CHD group. Data is presented below (mean ± SD; * p<.05).TableCONCLUSIONS: This data suggests that VO2peak increases following successful transplantation are due primarily to changes in cardiovascular function, since there was an increase peak cardiac output and peak heart rate. It is also possible that oxygen delivery to the working muscle increased as evidenced by significant reduction in total peripheral resistance at peak exercise.