Renal Transplantation and Vascular Surgery
Transplant questions test donor and recipient selection, immunosuppression, and the differential diagnosis of a rising creatinine. Vascular questions cover renal artery disease, aortic pathology and the urological complications of transplantation.
Donors, recipients and matching
- Donor types: living, donation after brain death, donation after circulatory death. Living donation gives superior graft survival; donation after circulatory death adds warm ischaemia and raises delayed graft function rates.
- HLA matching, ABO compatibility and a negative crossmatch are prerequisites; cold ischaemia time should be minimised.
- Recipient workup: cardiac assessment, screening for hepatitis B and C, HIV and tuberculosis, malignancy-free intervals, obesity and bladder function.
Immunosuppression
- Induction with basiliximab or anti-thymocyte globulin; maintenance with tacrolimus, mycophenolate and steroids, with mTOR inhibitors in selected patients.
- Calcineurin inhibitor toxicity is dose-related and can mimic rejection; only biopsy with histology and donor-specific antibody testing distinguishes them reliably.
Complications
- Early: vascular thrombosis, delayed graft function, urine leak, acute rejection (T-cell mediated or antibody mediated with donor-specific antibodies and C4d staining), wound infection.
- Later: ureteric stenosis at the ureteroneocystostomy usually between 1 and 3 months, lymphocele, transplant renal artery stenosis between 3 months and 2 years, incisional hernia.
- Infection: cytomegalovirus, BK virus nephropathy with decoy cells and rising BK PCR, Pneumocystis pneumonia prophylaxis for about 6 months, Epstein-Barr virus related post-transplant lymphoproliferative disease.
Vascular disease
- Atherosclerotic renal artery stenosis is ostial, in older smokers; fibromuscular dysplasia is mid-arterial, beaded, in young women. Revascularisation is reserved for refractory hypertension, flash pulmonary oedema or progressive renal impairment.
- Aortic aneurysm with a horseshoe kidney or renal mass with venous thrombus requires tailored operative planning.
Worked example
Three months after a living-donor transplant, creatinine rises from 120 to 210 micromol/L. Tacrolimus trough is 4 ng/mL against a target of 6-8, Doppler is normal, and BK PCR is 100000 copies/mL. The likely diagnosis is BK virus nephropathy, not rejection, so reduce immunosuppression, switch mycophenolate to leflunomide or low-dose sirolimus, and confirm with biopsy. Pulsing steroids here would worsen viral replication.
Traps that cost marks
Treating a rising creatinine as rejection without biopsy or BK testing; missing ureteric stenosis; forgetting Pneumocystis prophylaxis; not dose-adjusting drugs to renal function; overlooking donor-specific antibodies in late graft dysfunction.