Indices of Systemic Atherosclerosis Are Superior to Ultrasound Resistance Indices for Prediction of Allograft Survival

Background: In renal allograft recipients, ultrasound resistance indices (RI) have been discussed as predictors of transplant survival. RI measurements are correlated with subclinical atherosclerosis. It is thus unclear whether RI measurements represent specific markers of allograft damage or merely reflect systemic vascular damage. We studied whether RI are superior outcome predictors compared to markers of subclinical atherosclerosis and global cardiovascular risk.

Methods: In 105 renal transplant patients, intrarenal RI and common carotid intima-media thickness (IMT) were measured. Risk for coronary heart disease was determined by Framingham risk scoring (FRS). Patients were followed up for 5.4 +/- 0.4 years. The combined end point was a decrease of > or =50% in estimated glomerular filtration rate, need for dialysis or death.

Results: Both an increased IMT and a high FRS were predictors of the combined end point. In contrast, increased RI did not significantly predict the combined end point in the entire cohort. Only among low-risk patients with either normal IMT or FRS < or =20%, high RI measurements were associated with allograft loss.

Conclusions: Compared to markers of cardiovascular risk or systemic atherosclerosis, renal RI are inferior outcome predictors in unselected transplant recipients. Only in patients with mild or moderate cardiovascular risk may RI measurements allow additional risk stratification.