Transplant Renal Vein Stenosis: Diagnosis and Intervention

Although transplant renal artery stenosis (TRAS) is well documented and studied, transplant renal vein stenosis (TRVS) and venous outflow stenosis are relatively underreported and possibly underrecognized entities, only rarely described in single case reports (1Mei Q. He X. Lu W. Li Y. Renal vein stenosis after renal transplantation: treatment with stent placement.J Vasc Interv Radiol. 2010; 21: 756-758Abstract Full Text Full Text PDF PubMed Scopus (3) Google Scholar, 2Cercueil J.P. Chevet D. Mousson C. Tatou E. Krause D. Rifle G. Acquired vein stenosis of renal allograft—percutaneous treatment with self-expanding metallic stent.Nephrol Dial Transplant. 1997; 12: 825-826Crossref PubMed Scopus (14) Google Scholar, 3Obed A. Uihlein D.C. Zorger N. et al.Severe renal vein stenosis of a kidney transplant with beneficial clinical course after successful percutaneous stenting.Am J Transplant. 2008; 8: 2173-2176Abstract Full Text Full Text PDF PubMed Scopus (25) Google Scholar, 4Pan M.S. Wu R.H. Sun D.P. Tian Y.F. Chen M.J. Renal vein stenosis with transudative ascites from graft after renal transplantation with good response after percutaneous stent placement.Transplant Proc. 2014; 46: 598-601Crossref PubMed Scopus (3) Google Scholar). TRVS can result in graft injury and, if left untreated, irreversible graft failure. Endovascular intervention is a potential treatment option; however, there exist minimal data regarding the technique, safety, and efficacy of these procedures. In this study, the authors conducted a retrospective review of all renal transplants from 1998 to 2020 at a large transplantation center and identified a series of 5 unique patients with venous stenosis after renal transplantation (Table).TableA Case Series of 5 Patients with Transplant Renal Venous StenosisPatient 1Patient 2Patient 3Patient 4Patient 5Age (y), sex40, Female31, Female70, Male61, Male44, FemaleType of transplantCadavericLivingCadavericLivingCadavericLateralityRightLeftRightLeftRightTime of detection of transplant venous stenosis3 mo3 wk5 mo8 y5 moModality of detectionUltrasound, MRVMRVUltrasoundMRVUltrasoundVenous PSV (cm/s)249N/A30N/A299Location of stenosisTRVExternal iliac veinTRVCommon iliac veinExternal iliac vein and TRVStent9-mm × 20-mm SMART (Cordis, Miami Lakes, FL)10-mm × 40-mm Absolute (Abbott, Abbott Park, IL)8-mm × 30-mm Absolute14-mm × 60-mm Venovo (BD, Franklin Lakes, NJ)12-mm × 40-mm SMART (for the iliac vein) and 9-m × 20-mm SMART (for the renal vein)Posttransplant creatinine nadir (mg/dL)0.80.92.01.11.4Preinterventional creatinine (mg/dL)1.07.13.11.51.9Postinterventional creatinine (within 1 mo) (mg/dL)0.82.41.51.11.0Longest follow-up time (y)3N/A223Graft survivalYesNoYesYesYesMRV = magnetic resonance venography; N/A = not available; PSV = peak systolic velocity; TRV = transplant renal vein. Open table in a new tab MRV = magnetic resonance venography; N/A = not available; PSV = peak systolic velocity; TRV = transplant renal vein. Patient age ranged from 31 to 70 years (mean, 49.2 years). Three deceased and 2 living donor kidney transplants were encountered. The donor kidneys were placed into the retroperitoneal space, with a standard end-to-side fashion of the transplant renal vein (TRV) to the external iliac vein. In all cases, an increasing creatinine level prompted further evaluation with either magnetic resonance venography or ultrasound (US). In 2 cases, imaging demonstrated TRVS, and in 2 other cases, stenosis was noted within the adjacent iliac outflow vessel (Fig a). In 1 case, there was TRVS and iliac outflow vessel stenosis, secondary to a twisting/kinking of the vasculature from a rotated graft. The most consistent US finding of stenosis was aliasing at the region of narrowing. Elevated peak velocities (PVs) within the stenosed vein varied greatly, ranging from 30 to 299 cm/s (Fig b). Detection of TRVS occurred at 1 week, 3 weeks, 5 months, and 8 years after transplantation. Immediate endovascular intervention was performed in each patient after diagnosis, with carbon dioxide venography used as the primary diagnostic and therapeutic modality. Minimal (2–3 mL) contrast was used in each case to verify the presence of stenosis and perform accurate measurements for stent selection and for posttreatment venography (Fig c). In each case, catheter-directed venography confirmed severe (>75%) iliac vein stenosis (peripheral to the anastomosis) or TRVS. Angioplasty and stent placement were performed, which successfully resolved the venous stenosis in all cases. Stents were oversized by approximately 10% on the basis of the measurements on venography. Patients were maintained on dual antiplatelet therapy after the procedure for 3 months, with aspirin to continue indefinitely thereafter. In all cases, the postinterventional creatinine level immediately improved. Follow-up data for 2 years were reviewed. In 4 patients, creatinine values and follow-up US of the transplant kidney demonstrated durable improvements in graft function and a widely patent TRV (Fig d, e). In 1 patient, graft failure occurred secondary to rejection 3 months after intervention. Impairment of venous outflow results in high vascular back pressures, venous hypertension, and, ultimately, renal failure. This case series demonstrated that endovascular therapy with angioplasty and stent placement can be a rescue therapy for renal transplants with venous stenosis, with durable results reflected in high primary patency on follow-up imaging and improved markers of graft function. Overall, serum creatinine concentration in this study improved by 53% (a mean decrease in creatinine concentration of 1.6 mg/dL) by 1 month after the procedure. Compared with those of TRAS, scant data exist regarding the incidence and treatment of TRVS. This may be related to underrecognition and less vigilance paid to the venous structures at the time of US screening. US, unlike cross-sectional imaging, allows for vascular velocity measurements and waveform analysis and does not require contrast. Although there are numerous metrics to identify TRAS, including PVs, tardus parvus waveforms, and resistive indices, no such agreed upon values for TRVS are available (1Mei Q. He X. Lu W. Li Y. Renal vein stenosis after renal transplantation: treatment with stent placement.J Vasc Interv Radiol. 2010; 21: 756-758Abstract Full Text Full Text PDF PubMed Scopus (3) Google Scholar,2Cercueil J.P. Chevet D. Mousson C. Tatou E. Krause D. Rifle G. Acquired vein stenosis of renal allograft—percutaneous treatment with self-expanding metallic stent.Nephrol Dial Transplant. 1997; 12: 825-826Crossref PubMed Scopus (14) Google Scholar). In this study, the presence of aliasing at the region of stenosis was the most consistent finding. Although all patients also demonstrated elevated velocities at the renal vein, the peak venous velocities varied greatly (30–299 cm/s). TRAS classically develops within days to weeks after transplantation with imminent organ failure if unrecognized and untreated. In contrast, the timing of TRVS is less understood and predictable. In this study, discovery of TRVS differed significantly between patients, ranging from weeks to years after transplantation. Patients who presented more than a month after the postoperative period presented with iliac vein outflow stenosis, whereas patients who presented within the first month after transplant were found to have significant stenosis within the TRV itself. This also suggests that venous outflow stenosis is somewhat tolerated and well compensated and may present as very slow progression of graft dysfunction. These long periods between transplantation and detection of graft dysfunction also highlight the utility of long-term US surveillance. At the authors’ institution, US is used to regularly follow up with patients who underwent renal transplant, especially those with deteriorating kidney function on laboratory analysis, with careful attention paid to elevations in PVs. Magnetic resonance venography with or without contrast can be used to confirm the diagnosis of a venous stenosis. In conclusion, TRVS is a likely underrecognized entity that, if left untreated, could lead to allograft failure. Venous ultrasonography is an effective screening and diagnostic tool, and if venous stenosis is identified, angioplasty and stent placement result in long-term preservation of graft function. The authors thank Dr Nitin N. Katariya for his contributions to this manuscript.