Kidney transplantation (NTx, NTPL) is the surgical transfer of a kidney. Along with dialysis, it represents an option in renal replacement therapy and is performed in cases of terminal renal insufficiency (= permanent failure of kidney function before, leading to an increase in urinary substances in the blood) or loss of both kidneys.
Indications (areas of application)
- Terminal renal failure
- Loss of both kidneys
Transplants are organs from brain-dead organ donors (death donation) and from living donors. Living donation ideally takes place preemptively, that is, before dialysis.
Prerequisites: Donor and recipient must be thoroughly tested prior to transplantation. This includes tests that can be summarized as histocompatibility testing:
- Blood grouping
- HLA system
Only if these characteristics match, a successful transplant can take place. In addition, the donor’s blood is tested for various pathogens such as cytomegalovirus (CMV), human herpes viruses or Toxoplasma gondii to prevent transmission of pathogens to the recipient.
The surgical procedure
Kidney transplantation is usually performed heterotopically, which means that the donor organ is not transplanted in the place of the patient’s own kidneys, but outside the peritoneum (abdominal wall) in the pelvic area. The blood vessels of the donor kidney are usually sutured to the pelvic vessels, while the transplant ureter is connected directly to the bladder. As a rule, the patient’s own kidneys usually remain in the body; only in special indications do they have to be removed before or after transplantation.
The 5-year functional rate after living donation is 87.5% and after dying donation is about 70%.
Potential complications
- Infections
- Bleeding
- Stenosis (narrowing) of the transplant ureter.
- Graft rejection
- Formation of an incisional hernia (scar hernia) after surgery.
- Occurrence of malignancy (cancer; e.g., cutaneous squamous cell carcinoma/squamous cell carcinoma of the skin) after immunosuppressive therapy (rare).
Pharmacotherapy: after renal transplantation, the recipient must take immunosuppressants for life to prevent graft rejection. Note: The randomized TUMORAPA trial found that patients with cutaneous squamous cell carcinoma after renal transplantation were less likely to develop secondary skin tumors, even five years after switching to sirolimus (rapamycin) for immunosuppression, than patients who continued therapy with a calcineurin inhibitor (22% versus 59%).
Additional notes
- In the absence of a living HLA-compatible donor, there is the possibility of desensitizing the recipient. For this purpose, HLA antibodies are removed from the recipient’s blood by plasma exchange. Subsequent immunosuppressive therapy prevents new antibodies from forming. Additional therapy with rituximab (monoclonal antibody (IgG-1-kappa immunoglobulin) against the surface antigen CD20) inhibits the formation of B cells. Other therapeutic agents include bortezomib (proteasome blockade) and eculizumab (monoclonal antibody directed against complement factor C5). One study compared survival rates of three groups (1st group: living donation after desensitization; 2nd group: HLA-matched kidney donation; 3rd group: patients who never received an organ). Survival rates:
- After 1st year: 95% vs 94% and 89.6%, respectively.
- After the 3rd year: 91.7% versus 83.6% and 72.7%, respectively.
- After the 5th year: 86% versus 74.4% and 59.2%, respectively.
- After the 8th year: 76.5% versus 62.9% and 43.9%, respectively.
