Association of Intrarenal Resistance Index and Systemic Atherosclerosis After Kidney Transplantation

Patients after kidney transplants are at risk of cardiovascular morbidity. An elevated resistance index (RI) is associated with renal graft failure, while a decreased RI can be due to a renal artery stenosis. The RI can also be measured in the carotid artery. Whether a correlation between intrarenal RI after kidney transplant in adult patients and the RI of the internal carotid artery exists is still unclear.

In this prospective cross-sectional study, RI of kidney transplants and of the internal carotid artery were measured with duplex sonography. Carotid intima-media thickness as well as the Framingham risk score and the Augmentation index, all known markers of atherosclerosis, were assessed. Correlations between the RI in Carotid artery and the RI of the kidney transplant were based on Spearmen test with the level of significance set at p<0.05.

Ninety-eight consecutive patients [60% male, mean age of 48.7 (±15.6)] were included. The mean interval after transplantation was 27.5 (±8.5) months and mean serum creatinine was 308 (±220.3) mmol/ml The RI of the internal carotid artery and the renal transplant were significantly correlated (p<0.05). A correlation between the RIs and the Augmentation Index was found.

The RI of the kidney transplant is correlated with the RI of the carotid artery and to markers of general atherosclerosis. This observation may be helpful to identify patients after kidney transplant with higher risk for cardiovascular events and gain indirect information on transplant renal artery stenosis.