|Year : 2018 | Volume
| Issue : 1 | Page : 13-16
Incidence and outcome of transplant renal artery stenosis: A single-center experience
K Kawaskar, T Balasubramaniyan, N Gopalakrishnan, T Dinesh Kumar, K Chandrasekaran, R Sakthirajan, J Dhanapriya
Department of Nephrology, Rajiv Gandhi Government General Hospital, Madras Medical College, Chennai, Tamil Nadu, India
|Date of Web Publication||29-Mar-2018|
Dr. K Kawaskar
Superspeciality Hostel, Rajiv Ghandhi Government General Hospital, Madras Medical College, Chennai - 600 003, Tamil Nadu
Source of Support: None, Conflict of Interest: None
Introduction: Transplant renal artery stenosis (TRAS) is a recognized, potentially curable cause of posttransplant arterial hypertension, allograft dysfunction, and graft loss. Aim: This study aims to study the incidence, clinical presentation, and outcome of TRAS in renal allograft recipients. Materials and Methods: This is a retrospective study done at the Institute of Nephrology, Madras Medical College, from January 2009 to November 2016. Demographic data, type of renal donor, and posttransplant evaluation including delayed graft dysfunction, acute rejection, cytomegalovirus status, blood pressure profile, and graft function were studied. Laboratory and investigation data including serum potassium, lipid profile, Doppler transplant renal artery, and angiogram were analyzed. Results: Five hundred and twenty-six renal allograft recipients were studied; 7 patients had TRAS (1.3%). The timeline of TRAS ranged from 3 to 30 months (median: 5 months) after transplant. Three patients (42%) presented with refractory hypertension, six (85%) patients developed allograft dysfunction, and three (42%) patients presented with anuria. All patients were treated with percutaneous transluminal angioplasty with stenting, and one patient had recurrent TRAS after 1 year and treated with balloon angioplasty and stenting. Among seven patients, three patients have normal graft function, three had chronic graft dysfunction, and one patient had graft loss. Conclusion: The incidence of TRAS in the study was 1.3%. Early detection and correction reduce patients morbidity and allograft dysfunction.
Keywords: Doppler ultrasonography, percutaneous transluminal angioplasty with stenting, transplant renal artery stenosis
|How to cite this article:|
Kawaskar K, Balasubramaniyan T, Gopalakrishnan N, Kumar T D, Chandrasekaran K, Sakthirajan R, Dhanapriya J. Incidence and outcome of transplant renal artery stenosis: A single-center experience. Indian J Transplant 2018;12:13-6
|How to cite this URL:|
Kawaskar K, Balasubramaniyan T, Gopalakrishnan N, Kumar T D, Chandrasekaran K, Sakthirajan R, Dhanapriya J. Incidence and outcome of transplant renal artery stenosis: A single-center experience. Indian J Transplant [serial online] 2018 [cited 2018 Aug 21];12:13-6. Available from: http://www.ijtonline.in/text.asp?2018/12/1/13/228923
| Introduction|| |
Transplant renal artery stenosis (TRAS) is a recognized, potentially curable cause of postrenal transplant arterial hypertension, allograft dysfunction, and graft loss. TRAS usually arises close to the surgical anastomosis, but pre- and post-stenosis may also occur. TRAS occurs most frequently in the first 3–24 months although it can present at any time. Doppler sonography is commonly used as screening tool whereas angiography plays a key role in definite diagnosis. Since TRAS is potentially treatable, timely diagnosis and intervention favors good prognosis. The reported incidence of TRAS in different series ranged from 1% to 12%.
| Materials and Methods|| |
A retrospective analysis of our database between January 2009 and November 2016 was studied. Demographic data, organ donor characteristics, and posttransplant evaluation including delayed graft function, blood pressure (BP) profile, and graft function were studied. Laboratory and investigation data including serum potassium, lipid profile, Doppler renal artery, and angiogram were analyzed. The clinical diagnosis of TRAS was based on uncontrolled refractory/new-onset hypertension and unexplained graft dysfunction in the absence of rejection, obstruction, or infection. All patients with suspected TRAS had Doppler ultrasound measuring peak systolic velocity (PSV), resistive index, arterial, and venous flow. The Doppler criteria for diagnosing TRAS are acceleration time in the transplant renal and intrarenal arteries >0.1 s, PSV in the transplant renal artery >200 cm/s, and a ratio of PSV in the transplant renal to external iliac arteries >1.8. Elevated PSV in the transplant renal artery is the most sensitive Doppler criterion for the detection of high-grade TRAS. Graft characteristics and dilatation of collecting system were noted. The indications for stenting are uncontrolled hypertension, worsening of renal function, and progression of stenosis. Primary outcomes of this study were to assess survival rate, percentage of restenosis, and graft loss. Secondary outcomes were to analyze the reduction of BP, graft function, and number of antihypertensive medications.
| Results|| |
Among 526 renal allograft recipients, seven patients had TRAS (1.3%). The native kidney disease was known in three patients (focal segmental glomerulosclerosis: 1, diabetic nephropathy: 1, IgA nephropathy: 1). Out of 7 patients, four (57%) were males. Six of the seven renal transplant recipients are from deceased donors. Six patients presented with allograft dysfunction, three patients presented with refractory hypertension, and three patients presented with anuria. All donor kidneys had single renal artery anastomosed in end-to-end fashion to internal iliac artery. The timeline of TRAS ranged from 3 to 30 months (median: 5 months) postrenal transplant. Screening Doppler showed significant hemodynamic changes in all patients and intervention done in all cases.
We performed a paired two-sample Student's t-test to compare pre- and post-operative levels of serum creatinine and BP and estimated glomerular filtration rate (eGFR). The number of antihypertensive medications was compared with the use of Wilcoxon rank test. P = 0.05 was considered the threshold of statistical significance.
General demographics and laboratory parameters are shown in [Table 1] and [Table 2].
The mean PSV of transplant renal artery by Doppler USG was 245 ± 20 cm/s. All patients had significant stenosis at anastomotic site; all were treated with percutaneous transluminal angioplasty (PTA) with stenting, and one patient had recurrent TRAS due to in-stent restenosis and treated with balloon angioplasty and stenting. The efficacy of stenting in our study is suggested by decrease in mean systolic and diastolic BP, serum creatinine, and number of BP medications.
The mean serum creatinine [Figure 1] decreased from preprocedure value of 2.18 mg% to 1.6 mg% at 4 weeks and 1.4 mg% at 8 weeks (P< 0.05). The mean eGFR (MDRD formula) [Figure 2] increased from preprocedure value of 39.7 ml/min to 63.5 ml/min at 4 weeks (P< 0.05). The mean number of antihypertensive drug [Figure 3] requirement reduced from 2.5 to 2 drugs after 4 weeks postprocedure (P value not significant). Calcium channel blockers, alpha blocker, diuretics, and angiotensin-converting enzyme (ACE) inhibitors are used. Three patients were on ACE inhibitor during diagnosis. The average systolic BP [Figure 4] at presentation was 168.5 mmHg and it reduced to 140 mmHg after 4 weeks postprocedure (P< 0.05). The average diastolic BP [Figure 5] reduced from 101 to 91 mmHg after surgical intervention (P value not significant).
Out of seven patients, three patients have normal graft function (42.8%), three had chronic graft dysfunction (42.8%), and one patient had graft loss (14.2%). Two patients had pseudoaneurysm at puncture site at femoral artery which was managed conservatively, and one patient had restenosis. About 85.7% of the patients were deceased donor transplant recipients. Graft survival rate following intervention was 86%.
| Discussion|| |
TRAS is an increasingly recognized, potentially reversible complication of kidney transplantation. TRAS may be a consequence of faulty surgical technique, arterial damage during donor nephrectomy or kidney perfusion, kinking and compression of the renal artery, size discrepancy between donor and recipient renal arteries, and atherosclerosis of the donor or recipient renal arteries., Risk factors for TRAS include acute rejection episodes, cytomegalovirus infection, prolonged cold ischemia time, and progression of recipient atherosclerosis.,, The reported incidence of TRAS in different series ranged from 1% to 12%. The incidence of TRAS in our study was 1.3%. In an Indian study by Avinash et al., the incidence of TRAS was found to be 5.06%. PTA/stenting was done in all patients with technical success of 100%, and clinical success was 79.2% at 6 months. The most common presentation of TRAS are new-onset or refractory hypertension, graft dysfunction, or even acute renal failure because of overzealous diuretic therapy or addition of ACE or angiotensin receptor blocker to the antihypertensive treatment. Renal hypoperfusion activates renin-angiotensin system with resulting fluid retention, edema, cardiac failure, and recurrent pulmonary edema. Doppler ultrasonography (DUS) is commonly used as a screening tool in the initial evaluation. DUS has many advantages; it is noninvasive, inexpensive, has good sensitivity (87%–94%) and specificity (86%–100%), can evaluate hemodynamic significance, grading, and localization of stenosis, and can assess revascularization. Screening Doppler showed significant hemodynamic changes in all the patients in our study. Angiography is the gold standard for TRAS and provides a roadmap that is helpful in planning treatment procedure. The treatment modality differs depending on the severity of stenosis. The patient can be managed conservatively with low-dose ACE inhibitor if the stenosis is not hemodynamically significant with cautious monitoring of serum creatinine and potassium level. TRAS should be monitored by Doppler at least every 6 months for progression of stenosis. Hemodynamically significant stenosis is treated with PTA with or without stenting. PTA is minimally invasive procedure with success rate around 70%–90%. The success rate of PTA in our study was 85.7%. One patient had recurrent TRAS after 1 year due to in-stent restenosis at anastomotic site and treated with balloon angioplasty and stenting with successful restoration of graft function. In a largest Indian series, 43 patients with TRAS had been reported by Sriram et al.; only 11 patients with significant stenosis were intervened with significant increase in GFR and BP control after intervention , [Figure 6] and rest of them managed conservatively. Surgical reconstruction of the transplant renal artery is indicated when the restenosis is at the same anastomotic site, kinks, failed PTA, and recurrent lesions. Early diagnosis is crucial for successful restoration of graft function and to prevent complications.
|Figure 6: Computed tomography angio showing stenotic segment in the right side and successful recanalization in the next image|
Click here to view
| Conclusion|| |
- The incidence of TRAS in the study was 1.3%
- About 85.7% of the patients were deceased donor transplant recipients
- Graft survival rate following intervention was 86%.
We would like to thank Dr. Periyakaruppan, interventional radiologist and Dr. Sriram, interventional cardiologist for their contribution in successfully treating the patients.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6]
[Table 1], [Table 2]