To evaluate the clinical value of contrast-enhanced ultrasound (CEUS) in evaluating the short-term outcome of stent implantation for transplant renal artery stenosis (TRAS).

A total of 25 TRAS patients with stent implantation were admitted to Jinling Hospital affiliated to Nanjing University (Eastern Theater Command General Hospital) from January 2011 to December 2020. CEUS was performed 24 h after the surgery, and the time-intensity curve (TIC) was analyzed to obtain the area under curve (AUC). All patients were divided into either a poorly-perfused group (AUC≤865 dB·s; 9 cases) or a well-perfused group (AUC＞865 dB·s; 16 cases) according to the AUC. Clinical data including age, gender, course of disease, site and degree of stenosis, blood pressure, renal function, and TIC parameters (arrival time, peak intensity, and time to peak), and postoperative renal function deterioration were compared using the independent sample t test or χ² test.

Compared with the well-perfused group, the poorly perfused group had shorter course of stenosis after balloon dilation [(3.5±2.1) months vs (4.8±1.6) months], the degree of renal artery stenosis was more severe [(85.4±8.6)% vs (80.1±7.9)%], and the stenosis was longer [(15.5±7.4) mm vs (13.5±6.3) mm]; the differences were statistically significant (t=3.457, 5.452, and 7.746; P=0.049, 0.035, and 0.021, respectively). After stent implantation, compared with the well-perfused group, serum creatinine in the poorly perfused group was higher [(325.6±115.3) μmol/L vs (212.5±103.4) μmol/L] and estimated glomerular filtration rate was lower [(61.8±11.7) ml/(min·1.73 m²) vs (72.5±12.4) ml/(min·1.73 m²)], while cortical peak intensity was weaker [(28.8±8.6) dB vs (33.4±10.3) dB] and time to peak was longer [(24.6±7.9) s vs (20.9±6.7) s]; the differences were statistically significant (t=5.735, 5.343, 6.125, and 7.950; P=0.019, 0.026, 0.020, and 0.009, respectively). The mean follow-up time was 10.5±1.6 months, and the proportion of patients in the poorly perfused group was significantly higher than that in the well-perfused group (12.0% vs 4.0%, χ²=5.297, P=0.021).

CEUS can be used to evaluate the short-term outcome of TRAS stent implantation by evaluating renal cortical blood perfusion. Lower peak intensity and longer time to peak on CEUS can predict poor cortical blood perfusion of the transplanted kidney and increased possibility of short-term transplant renal function deterioration after stent implantation in TRAS patients, thus providing a reference for screening patients suitable for interventional therapy.