Association of Increased Arterial Wave Reflections With Decline in Renal Function in Chronic Kidney Disease Stages 3 and 4

BACKGROUND: Increased arterial wave reflections predict cardiovascular events in dialysis patients. Their impact on the progression of renal disease has not been determined. METHODS: We prospectively quantified wave reflections as pressure augmentation (AP) and augmentation index (AIx) using radial applanation tonometry and a transfer function, in 111 patients (mean age 53.6 years; 71 men, 31 diabetics) with chronic kidney disease not requiring dialysis. Primary endpoint was a composite of doubling of serum creatinine, need for dialysis, and transplantation. Secondary endpoint was a combination of renal and cardiovascular events. RESULTS: After a mean follow-up of 41.3 months, 37 and 46 patients reached the primary and the secondary endpoint. AIx and AP proved statistically significant predictors of the renal endpoint (P < 0.05 for all), with a 2.5- and 3-fold increased risk for patients in the highest vs. the lowest tertile, respectively. After adjustment for mean blood pressure (MBP), age, gender, diabetes, serum albumin, hemoglobin, urine albumin/creatinine ratio, and renal function at baseline, AIx (hazard ratio 1.474/10% increase in AIx, P = 0.04) as well as AP (hazard ratio 1.559/10 mm Hg increase in AP, P = 0.04) remained significant predictors of the renal endpoint. In addition, AIx and AP were significant (P < 0.05) predictors of the combined cardiorenal endpoint in univariate analysis and multivariable models. CONCLUSION: Increased arterial wave reflections are independent predictors of renal as well as cardiorenal events in patients with chronic kidney disease.