Significance of Resistive index in Renal Transplantation

Song, Hyun Og; Seong, In Gi; Han, Bo Hyun

Abstract

The increasing use and availability of renal transplantation has resulted in a demand for noninvasive methods to study possible complications. One of the most serious adverse reactions is acute rejection, a possibly reversible cause of transplant failure if treated promptly. Sixty-six donors and recipients were evaluated by duplex Doppler examination of intrarenal arteries. A simplified formula, resistive index(RI) ([peak systolic frequency shift-lowest diastolic frequency shift]/[peak systolic frequency shift]), were used to diagnose rejection. All RI values of donors were within normal limit. RI values of recipients were not significantly different according to the number of renal artery and the ischemic time during operation. With a RI greater than 0.90, a 100% positive predictive value was obtained for the diagnosis of acute rejection. A 88% positive predictive value of acute rejection was obtained with a RI greater than 0.80. A value less than 0.70 was unlikely to be rejection(negative predictive value, 95%). The results suggest that the duplex Doppler examination and the resistive index obtained by simple analysis of the wave form would be used as a valuable noninvasive method for the detection of acute renal transplant rejection. The findings of Doppler examination are not necessarily pathognomonic for one specific process, but they can aid the clinician in deciding the kind of treatment necessary and the need for biopsy.