Loss of the Normal Gradient in Arterial Compliance and Outcomes of Chronic Kidney Disease Patients.

Background: In dialysis patients, loss of the normal gradient in arterial compliance, assessed by the pulse wave velocity (PWV) ratio, predicts all-cause mortality better than does carotid-femoral PWV (CF-PWV) alone. However, the prognostic significance of the PWV ratio for outcome in chronic kidney disease (CKD) patients remains unclear.

Methods: In this longitudinal cohort study, CKD patients who visited our CKD management clinic between April 27, 2006, and March 27, 2008, were included and followed up. To assess the gradient in arterial compliance, the PWV ratio was calculated using CF-PWV divided by carotid-radial PWV.

Results: A total of 209 patients in CKD stages 1-4 with a median follow-up of 3.74 years were included. Patients with higher PWV ratio were relatively older (p < 0.001) and had worse renal function (p < 0.001), more hypertension (p < 0.001), diabetes mellitus (p < 0.001), and cardiovascular or cerebrovascular disease (p < 0.001). The median time to patient outcome (death, renal replacement therapy, or double increase in serum creatinine from baseline) in the group with a PWV ratio above the median (89.8 months, 95% CI 84.2-95.5) was shorter than that in the group with a PWV ratio below the median (105.3 months, 95% CI 101.3-109.3, p = 0.001). Univariate Cox regression analysis showed that both PWV ratio and CF-PWV were significantly associated with patient outcome. In multivariate Cox regression analysis, both PWV ratio and CF-PWV were associated with patient outcome. However, the HR for CF-PWV (2.177, 95% CI 1.064-4.453, p = 0.033) was slightly higher than that for PWV ratio (2.091, 95% CI 1.049-4.167, p = 0.036). There was a significant interaction effect between PWV ratio and CKD stage. It was shown that patients with advanced CKD stages and higher PWV ratios had a significantly higher risk of adverse CKD outcome (p = 0.006).

Conclusions: The PWV ratio, as a measure of loss of the normal gradient in arterial compliance, was associated with CKD patient outcome. Patients with advanced CKD and a higher PWV ratio had a significantly higher risk of adverse CKD outcome.