Effects of age and chronic kidney disease on regional aortic distensibility: a cardiovascular magnetic resonance study.

BACKGROUND

Chronic kidney disease (CKD) is associated with increased arterial stiffness, an independent predictor of adverse cardiovascular outcome. Effects of CKD on regional aortic stiffness are unknown. This study aimed to determine the effects of CKD and ageing on regional thoracic aortic distensibility using cardiac magnetic resonance (CMR) imaging.

METHODS

This was a cross-sectional case control study comparing patients with stage II-IV non-diabetic CKD recruited from a university hospital with healthy controls. Aortic distensibility was measured in triplicate using CMR (1.5 T) at ascending, proximal descending and distal descending thoracic aortic levels and calculated using previously validated formulae.

RESULTS

189 patients and 40 controls were recruited. Distensibility was reduced at all three thoracic aortic levels in CKD patients compared to controls (2.8 vs. 4.1 × 10(-3) mmHg(-1); P < 0.0005 for ascending aorta). The cohort was divided into tertiles of age and glomerular filtration rate (GFR); distensibility decreased with increasing age (P < 0.0005) and decreasing GFR (P < 0.02). In univariate analyses age (r = -0.688, P < 0.0005), systolic blood pressure (r = -0.183, P = 0.006) and GFR (r = 0.172, P = 0.009) all correlated with ascending aortic distensibility. In a multivariate regression model age and GFR were independent predictors of aortic distensibility at all three levels with 50% of the variation in ascending aortic distensibility explained (P < 0.0005).

CONCLUSIONS

Patients with early stage chronic kidney disease have reduced distensibility along the entire length of the thoracic aorta. This worsens with ageing and as kidney function declines, emphasizing the importance of early treatment whilst kidney function is still relatively preserved.