Clinical and Radiological Predictors of Transplant Renal Artery Stenosis (TRAS)

H. Wadei,¹ D. Hodge,² L. White,² A. Ayub,³ N. Aslam,³ T. Gonwa,¹ G. Frey,⁴ D. Sella,⁴ M. Mai.¹

¹Transplant, Mayo Clinic, Jacksonville, FL
²Biomedical Statistics, Mayo Clinic, Jacksonville, FL
³Department of Medicine, Division of Nephrology and Hypertension, Mayo Clinic, Jacksonville, FL
⁴Diagnostic Radiology, Mayo Clinic, Jacksonville, FL.

Meeting: 2015 American Transplant Congress

Abstract number: 219

Keywords: Angiography, Hypertension, Renal dysfunction, Ultrasonography

Elevated peak systolic velocity (PSV) on Doppler ultrasound at the transplant renal artery (TRA) does not always correlate with true transplant renal artery stenosis (TRAS) Aim: Identify clinical and Doppler criteria that predict a diagnosis of TRAS on angiography. Methods: 42 patients with PCV ≥200 cm/s at the proximal or mid segments of the TRA underwent CO2 angiography. Data regarding BP, number of BP medications, allograft dysfunction (defined as >0.3 mg/dl rise in serum creatinine), clinical and chest X-ray evidence of pulmonary edema (PE) were retrospectively collected. Arcuate artery resistive indices (RI) were determined at the upper, mid and lower zones of the kidney and the average of the 3 readings was obtained. Patients on dialysis at time of angiography were excluded. Results: 14 (33%) patients had TRAS. Table 1 demonstrates clinical and radiological characteristics for patients with and without TRAS

Clinical and Radiological findings of 42 kidney transplant recipients according to TRAS diagnosis

	No TRAS (n=28)	TRAS (n=14)	P
Age at tx	56±12	57±14	0.7
% male	50	0.3	0.3
% Pre-emptive tx	28	7	0.2
% Living donor	18	17	1
% Pre-tx diabetes	64	64	1
Days from tx to angio	154(7-3263)	110(11-3093)	0.9
PSV at proximal TRA (cm/s)	212 ± 110	364 ± 230	0.05
PSV at mid TRA (cm/s)	138±69	220±126	0.03
Average RI	0.8±0.1	0.8±0.2	0.8

On logistic regression, the OR (CI) of TRAS diagnosis were 10.8 (1.07, 108.59) and 4.4 (1.05-18.4) for PE and allograft dysfunction, respectively (P=0.04 for both). In the 14 TRAS patients, the mean ± SD gradients across the stenotic segment were 32±27 and 7±5 mmHg before and after intervention, respectively, (p=0.007). Table 2 summarizes the effects of angioplasty on arterial BP and allograft function.

Table 2: BP and kidney function before and 1-month after angioplasty

	Before Angio (n=14)	1-month post angio (n=14)	P
SBP (mmHg)	142±23	133±13	0.1
DBP (mmHg)	72±12	64±13	0.04
Number of BP meds	3.3±1.2	2.8±1.8	0.2
serum cr (mg/dl)	3±2	1.8±0.6	0.001

Conclusion:1- Only a 33% of patients with elevated PSV on Doppler US have true TRAS. 2- PE and allograft dysfunction were predictive of clinically significant TRAS. 3- Allograft function and diastolic BP improves following successful angioplasty of TRAS.

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