Renal Transplantation

Introduction

Renal transplantation (RT) is the treatment of choice for patients with end-stage renal disease (ESRD).

Kidneys can be donated from either living donors or deceased donors, with the majority of renal transplants from deceased donors. Deceased donors are either Donation after Brainstem Death (DBD) or Donation after Circulatory Death (DCD).

Living-donor transplants account for up to 30% of all kidney transplantations, either related or unrelated, performed as a laparoscopic donor nephrectomy (rarely this is done as an open nephrectomy in modern practice).

One year survival for DBD transplant recipients is around 97% and for living donor transplant recipients is around 99%.

Indications

All patients with end stage renal failure (GFR<15 ml/min) or those with CKD stage 4 (GFR 15-29 ml/minute) with progressive disease should be assessed for renal transplantation.

Contraindications, both absolute and relative, to kidney transplantation are shown in Table 1.

Table 1 – Contraindications to renal transplantation

Surgical Techniques

Donor Retrieval Procedure

Organs are retrieved in a similar fashion using cold perfusion during both DBD and DCD retrievals. In DBD retrievals, there is also a period of dissection which allows assessment of the organs during the procurement process. During DCD retrieval, a rapid cannulation of the iliac artery with cold perfusion is performed to limit the exposure of the organs to warm ischaemia.

Full exposure of the abdomen is obtained and the bowel is mobilised to access to the retroperitoneal space. The donor is heparinised, then the vessels and ureter(s) are identified and isolated. The kidneys are then removed with the renal artery with a patch of aorta, the renal vein with a patch of the IVC, and the ureter. The organs are then taken to the back table for further examination and perfusion.

For living donor kidney transplantation, the nephrectomy is most commonly performed via a laparoscopic technique. The left kidney is preferred because of a longer renal vein, however no patch of aorta or IVC can be taken in these cases. Again, the kidney, once removed, should be flushed with preservation fluid as soon as possible. The mortality of donor nephrectomy is low, estimated at 1 in 3000 for all surgical approaches.

By TeachMeSeries Ltd (2020)

Figure 1 – The retroperitoneal position of the kidneys

Recipient Procedures

If transported from another centre, the kidney will arrive stored in perfusion fluid (within sterile bags) and surrounded by ice. The kidney should be benched and examined, the renal artery and vein identified, flushed with preservation solution (to check for leaks), and any leaks repaired, with the ureter length fully preserved and any additional surrounding fat removed.

The graft is placed extraperitoneally in the iliac fossa, most commonly the right side. Dissecting retroperitoneally in the iliac fossa, the iliac vessels are exposed and any lymphatics identified are ligated. Termino-lateral anastomoses are performed between donor renal vein and recipient external iliac vein, and between donor renal artery and recipient internal or external iliac artery.

The kidney is reperfused and the ureter is anastomosed to the bladder through the formation of an ureteroneocystostomy. The anastomosis is performed over a ureteric stent which can be removed around six weeks after the transplant.

By Aimee Rowe, TeachMeSurgery [CC-BY-NC-ND 4.0]

Figure 2 – The anatomical and anastomosis arrangement seen in renal transplantation; (A) end-to-end (B) end-to-side

Complications of Renal Transplant

Delayed Graft Function

Delayed graft function (DGF) is defined by the need for dialysis in the first week after transplantation. Its risk increases with prolonged WITs and CITs (therefore is relatively rare with living donor grafts). Whilst most DGF kidneys eventually function, there is a recognised association with increased rejection rates and decreased graft survival rates.

Vascular Complications

Vascular complications are divided in early and late.

Early complications comprise renal artery thrombosis (rare, 1%) and renal vein thrombosis (6%). They must be recognised promptly using a Doppler ultrasound and will require taking back to theatre urgently if identified. Aspirin and/or heparin are often started post-operatively to reduce this risk

Late complications include renal artery stenosis, which usually presents several months post transplantation with uncontrollable hypertension and worsening graft function. Angiography confirms the diagnosis and the treatment of choice is typically angioplasty.

Zeina AR, Vladimir W, Barmeir E. [CC BY 2.0 (https://creativecommons.org/licenses/by/2.0)]

Figure 2 – Angiogram following angioplasty, in patient with renal artery stenosis (in a native kidney)

Ureteral Complications

Ureteric leaks occur from a breakdown of the ureteric-bladder anastomosis, presenting with a decreased urine output and increasing abdominal pain. They often require repeat surgical intervention.

Urinary tract obstruction can also occur, through ischaemic strictures in the distal ureter (treated with dilatation) or extrinsic compression from a lymphocele or haematoma (treated via drainage).

Long-term Complications

The most common cause of mortality post-operatively within the first year is cardiovascular disease.

Most other longer term complications are often related to the use of immunosuppressive agents, such as recurrent infections, diabetes mellitus, or malignancy.