WHEN THE GRAFT’S LIFELINE NARROWS’- SUCCESSFUL REVASCULARISATION OF A THREATENED ALLOGRAFT

WHEN THE GRAFT’S LIFELINE NARROWS’- SUCCESSFUL REVASCULARISATION OF A THREATENED ALLOGRAFT
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Case summary:

A 22-year-old male with the end stage kidney disease secondary to Nephronophthisis, underwent a live related renal transplantation on 10/12/2025, with his aunt as the donor.

He received antithymocyte globulin (ATG) induction therapy followed by standard triple immunosuppression (Calcineurin inhibitor, antiproliferative agent and corticosteroids). The immediate postoperative period was uneventful, with prompt graft function and satisfactory urine output, suggestive of good early graft perfusion.

However, after the 10th post operative day, while still hospitalized, he developed accelerated hypertension accompanied by a rise in serum creatinine, raising concern for early graft dysfunction. Clinical examination revealed a significant bruit over the graft site, heightening suspicion for a vascular etiology.

Given the scute hemodynamic changes, a non-contrast MR renal angiography was performed, which demonstrated mild to moderate (40-50%) anastamotic stenosis of the transplant renal artery at its origin from the external iliac artery.

In view of worsening renal function and clinically significant hypertension, the patient underwent digital subtraction angiography (DSA) on 21/12/2025, which confirmed the lesion. Percutaneous transluminal angioplasty with renal artery stenting was successfully performed.

Following revascularization, there was rapid improvement in renal function, with serum creatinine declining to 1.46 mg/dl, along with better blood pressure control. The patient was subsequently discharged in a stable condition.

On continued follow up, he remains clinically well with stable graft function and controlled blood pressure, underscoring the importance of early recognition and timely intervention in transplant renal artery stenosis.

TRANSPLANT RENAL ARTERY STENOSIS

Transplant renal artery stenosis (TRAS) is a significant narrowing of the arterial supply to a renal allograft that impairs perfusion, leading to hypertension, graft dysfunction and potential graft loss. Incidence varies widely from 1-10% in various cohorts, with most cases presenting between 3 months to 2 years post transplant, but early and late presentations occur. Anatomic lesions are most commonly at the anastamotic site between the donor renal artery and recipient iliac artery. Risk factors include donor and recipient atherosclerosis, surgical trauma, delayed graft function, diabetes and arterial risk profiles.

PATHOPHYSIOLOGY:

TRAS results from both mechanical/surgical factors and vascular pathology.

Hemodynamic and ischemic cascade:

  • Critical narrowing causes reduced graft perfusion leading to activation of RAAS resulting in resistant hypertension.
  • Sustained ischemia leads to chronic ischemic nephropathy, tubulointerstitial injury and declining eGFR when left untreated.

Lesion characteristics:

  • Anastamotic suture line line stenosis due to technical mismatch or intimal hyperplasia. Recipient iliac atherosclerosis extending into the graft inflow.
  • Endothelial injury/immune-mediated processes potentially contribute but are less well defined.

CLINICAL PRESENTATION:

The presentation is varied and often non-specific:

  • Hypertension- New onset or worsening, resistant hypertension
  • Flash pulmonary edema
  • Graft dysfunction
  • Asymptomatic- found on regular doppler assessments

DIAGNOSIS:

  • Colour Doppler Ultrasound: First line non-invasive screening. Elevated peak systolic velocity (PSV), a high renal to iliac PSV ratio and turbulent flow support TRAS diagnosis.
  • CT angiography (CTA) or MR angiography (MRA) can localize stenosis and assess anatomy; limitations exist with contrast exposure in impaired renal function.
  • Digital subtraction Angiography (DSA): remains the gold standard and enables therapeutic intervention.

MANAGEMENT:

Management aims to improve perfusion, control hypertension, preserve graft function and minimize complications.

Medical management:

Indicated for mild/intermediate stenosis (<50%) with stable graft function. Priniciples of medical care including blood pressure control with careful selection of antihypertensives, antiplatelets and statins for atherosclerotic risk management along with surveillance imaging to track lesion progression.

Limitations: Purely medical therapy generally does not correct hemodynamically significant stenosis and is associated with ongoing risk of hypertension and ischemia.

Endocavscular intervention:

Percutaneous transluminal angioplasty (PTA) with/without stenting is the preferred modality in most centres.

Systematic reviews and cohort analysis show around 89% technical success, improved BP, decreased creatinine and reduced antihypertensive drug burden. Stent placement (especially in ostail/anastamotic lesions) tend to yield better patency and lower restenosis compared with PTA alone, although randomized trials are lacking. Complication rates are relatively low but include dissection, hematoma and restenosis.

Outcomes: Blood pressure control and creatinine improvement are frequently reported; graft survival is often similar to transplant patients without TRAS, when treated promptly.

Surgical management:

Indicated in patients with complex anatomy unsuitable for endovascular intervention, failed endovascular therapy or concomitant surgical needs (eg; pseudoaneurysm, graft revascularization).

Surgical repair historically showed variable outcomes and higher perioperative risks compared with endovascular approaches, making it a secondary option in most contemporary practices.

COMPLICATIONS:

Restenosis: Recurrence of significant narrowing post-intervention. Close surveillance with doppler is critical.

Procedure related complications: Dissection, thrombosis or embolism.

Long term follow up:

Regular BP monitoring, renal function tests and periodic imaging.

Adjust immunosuppressive and cardiovascular risk regimens accordingly.

REFERENCES:

  • Endovascular treatment of Transplant renal artery stenosis: Systematic review and Meta-analysis (Pubmed 2022)
  • Managemnet of post transplant renal artery stenosis and graft outcomes (Nephrology Dialysis Transplantation, 2025)
  • Transplant renal artery stenosis: Case Report and review (Urol J,2024)
  • Transplant renal artery stenosis: Current concepts (Exp Clin Transplant, 2022)
  • Incidence and predictors of TRAS (Am J Nephrol, recent registry data)
  • Dimitrijeva et al, Diagnosis and Endovascular management (Cureus, 2025)

Dr. Rashmi Shivram
Associate Consultant, Department of Nephrology
Kauvery Hospital, Alwarpet, Chennai.

Dr. Balaji Kirushnan
Senior Consultant Nephrologist
Kauvery Hospital, Alwarpet, Chennai.

Dr. R. Balasubramaniyam
Chief Nephrologist
Kauvery Hospital, Alwarpet, Chennai.