A clinical evaluation of VO₂ kinetics in kidney transplant recipients.

ABSTRACT:

Purpose

Aerobic exercise capacity is reduced in patients with chronic kidney disease, partly due to alterations at the muscular and microvascular level. This study evaluated oxygen uptake (VO₂) kinetics as indicator of muscular oxidative metabolism in a population of Kidney Transplant Recipients (KTRs).

Methods

Two groups of KTRs enrolled 3 (n = 21) and 12 months (n = 14) after transplantation and a control group of healthy young adults (n = 16) underwent cardiopulmonary exercise testing on cycle-ergometer. The protocol consisted in two subsequent constant, moderate-load exercise phases with a final incremental test until exhaustion.

Results

The time constant of VO₂ kinetics was slower in KTRs at 3 and 12 months after transplantation compared to controls (50.4 ± 13.1 s and 43.8 ± 11.6 s vs 28.9 ± 8.4 s, respectively; P < 0.01). Peak VO₂ was lower in KTRs evaluated 3 months after transplantation compared to patients evaluated after 1 year (21.3 ± 4.3 and 26.4 ± 8.0 mL/kg/min; P = 0.04). Blood haemoglobin (Hb) concentration was higher in KTRs evaluated at 12 months (12.8 ± 1.7 vs 14.6 ± 1.7 g/dL; P < 0.01). Among KTRs, τ showed a moderate negative correlation with Peak VO₂ (ρ = - 0.52) and Oxygen uptake efficiency slope (OUES) (r = - 0.57) while no significant correlation with Hb and peak heart rate.

Conclusions

KTRs show slower VO₂ kinetics compared to healthy controls. Hb and peak VO₂ seem to improve during the first year after transplantation. VO₂ kinetics were significantly associated with indices of cardiorespiratory fitness, but less with central determinants of aerobic capacity, thus suggesting a potential usefulness of adding this index of muscular oxidative metabolism to functional evaluation in KTRs.

SUBMITTER: Patti A 

PROVIDER: S-EPMC8192378 | biostudies-literature |

REPOSITORIES: biostudies-literature