Impaired Arterial Compliance and Aerobic Endurance in Kidney Transplant Recipients

Background: Cardiovascular disease is the leading cause of morbidity and mortality in kidney transplant recipients (KTR). Two risk factors for cardiovascular disease that have not been examined in this population are arterial compliance and aerobic capacity. The primary objective was to determine small and large artery compliance and aerobic endurance in KTR. A secondary objective was to explore the relationship between aging and arterial compliance and aerobic endurance in KTR.

Methods: Sixty-two clinically stable KTR were recruited from the University of Alberta Renal Transplant Clinic. Small and large artery compliance was assessed using computerized arterial pulse waveform analysis. Aerobic endurance was determined using the six-minute walk test. Age-matched normative data from healthy individuals was used for comparison.

Results: Small arterial compliance was lower in KTR (5.5+/-3 ml/mm Hg x 100) compared to age-matched healthy individuals' predicted values (7.9+/-0.9 ml/mm Hg x 100, P<0.0001). No difference was found for large artery compliance between KTR (16.0+/-6.6 ml/mm Hg x 10) and age-matched healthy predicted values (15.2+/-1.3 ml/mm Hg x 10, P=0.5). Small and large artery compliance were 35% (P=0.026) and 36% (P=0.005) higher in younger (<51 years) versus older (>51 years) KTR, respectively. The six-minute walk distance was 28% lower in KTR (495+/-92 m) compared to healthy age-predicted values (692+/-56 m P<0.0001).

Conclusions: Compromised arterial compliance and poor aerobic endurance may partially explain the high incidence of cardiovascular disease in KTR. Interventions demonstrated to improve these parameters may afford substantial clinical benefit in this population.