Clinical Utility of Duplex Ultrasonography in the Recognition of Transplant Renal Artery Stenosis: A Single Center Experience

<b>Introduction:</b> Renal artery stenosis can significantly impact long-term graft survival rates following kidney transplant. Early recognition and management can improve the longevity of the kidney allograft. We aimed to evaluate the clinical role of duplex ultrasound in the diagnosis of renal artery stenosis (RAS). We also wanted to evaluate the current incidence of renal artery stenosis at our institute. <b>Methods:</b> A retrospective, consecutive series of 367 patients who underwent renal transplantation between 1 January 2020 and 30 December 2024 was conducted. We collected data regarding the recipients' age, body mass index, and comorbidities. All patients diagnosed with renal artery stenosis were identified. The incidence of kidney transplant artery stenosis and presentation were recorded. All general physical parameters and laboratory data were collected and analyzed. <b>Results:</b> A total of 28 patients had initial suspicion of renal artery stenosis, documented via initial dedicated duplex ultrasound of the transplanted kidney. The initial mean systolic BP at initial US was 151 (99-213) mmHg, and mean creatinine was 2.43 (1.28-6.38) mg/dL. However, on repeat duplex ultrasound, three patients showed no features of renal artery stenosis and had no physical parameters consistent with RAS. A total of 25 patients diagnosed with RAS on initial duplex ultrasound underwent angiography. Twenty-four patients were confirmed with RAS on angiography, while one patient had a normal angiogram. Among patients diagnosed with TRAS, the mean resistive index was 0.71 ± 0.17 at the upper pole, 0.73 ± 0.19 at the mid pole, and 0.71 ± 0.21 at the lower pole. The mean peak systolic velocity was 462.57 ± 166.28 cm/s. <b>Conclusions:</b> Duplex ultrasound is an important initial tool for diagnosing transplant renal artery stenosis. An increase in peak systolic velocity was observed in our cohort; however, resistive indices were largely within acceptable limits. Management should be guided by clinical parameters (e.g., elevated systolic BP and rising creatinine) alongside imaging findings.