Purpose: Atherosclerotic vascular disease is the main cause of morbidity and mortality in patients with end-stage renal disease, but the independent contribution of renal failure rather than associated risk factors is unclear. We sought to examine the relative contribution of these factors to the severity of atherosclerosis by measuring intima-medial thickness and brachial artery reactivity in uremic patients and controls.
Subjects and methods: Cardiovascular risk factors, including lipid and homocysteine levels, were evaluated in 213 patients (69 on hemodialysis, 60 on peritoneal dialysis, and 82 nonuremic controls). High-resolution B-mode ultrasonography with automated off-line analysis was used to measure the intima-medial thickness in the common carotid artery and to measure the lumen diameter of the brachial artery at rest, during reactive hyperemia, and after sublingual nitroglycerine. The correlations of risk factors with intima-medial thickness and brachial reactivity were examined using a general linear regression model.
Results: Patients with renal failure had a greater mean (+/- SEM) maximum intima-medial thickness than controls (0.83 +/- 0.02 mm versus 0.70 +/- 0.02 mm, P < 0.05), but the brachial artery response to reactive hyperemia was not significantly different between the renal failure patients and the control group (4.7% +/- 6.1% versus 6.1% +/- 8.6% dilatation, P > 0.05). The uremic state was an independent predictor of intima-medial thickness (r2 = 0.16, P < 0.001) but not of brachial artery reactivity (P = 0.99).
Conclusion: The atherosclerotic burden in patients with renal failure, as indicated by an increased intima-medial thickness, may reflect effects of uremia that are independent of cardiovascular risk factors.