This comprehensive article outlines the process of kidney transplantation, from patient and donor selection to surgical techniques and post-operative care, including potential complications and rejection types.

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Indications

Chronic kidney disease stage 5 needs either dialysis or transplant. The most common etiologies of renal failure are diabetes and hypertension.

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Contraindications

Absolute contraindications are:

• Inability to tolerate surgery due to severe cardiac or pulmonary disease
• Active malignancy
• Active infection
• Active drug abuse
• Uncontrolled psychiatric disease

Relative contraindications are more variable and may differ depending on the institution and geographic region: morbid obesity, history of noncompliance with dialysis schedule or medication regimen, frailty, psychiatric problems, and limited life expectancy.

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Patient Selection

Most ESRD patients have multiple co-morbidities and complications resulting from their kidney disease. As such, they are carefully screened for their ability to tolerate surgery and the subsequent immunosuppression which accompanies transplant surgery. Below is a summary of the evaluation of comorbid conditions:

Cardiovascular disease: The leading cause of death after kidney transplantation is cardiovascular disease. Therefore, if noninvasive testing is positive, these patients should undergo cardiac revascularisation before transplant surgery.

Cerebrovascular disease: Any patient with a history of a cerebrovascular accident, including a transient ischemic attack, should be evaluated for carotid artery disease, if not already done.

Gastrointestinal disease: Anyone with a family or personal history of colon cancer or above the age of 50 should have a screening colonoscopy.

Hematologic disorder: Patients with a history of thrombosis should be evaluated for possible hypercoagulable disorders which may require treatment with anticoagulation.

Malignancy: Most transplant centres will require a cancer-free period of 2 to 5 years, depending on the type of cancer, to minimise the risk of post-transplant recurrence/metastasis potentiated by immunosuppressive therapy.

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Donor selection

Donors can be divided into living donors or deceased donors.

1. Deceased donors

Deceased donors are broken down into those who are brain dead (DBD) and those who donate after cardiac death (DCD). As the term would indicate, brain-dead donors are those who have satisfied formal criteria for brain death testing. DCD donors are patients who, while they do not meet the criteria for formal brain death, are deemed by neurologists as being unlikely to experience a meaningful neurologic recovery.

2. Living kidney donors

Living kidney donation offers the best graft and recipient survival, even when considering paired kidney exchange, which involves organ transport before implantation. The current eligibility criteria requirements are ages 18 to 65 years, BMI less than 35 kg/m, no active malignancy, no active infection, and adequate kidney function (~ GFR > 80).

Absolute contraindications to living kidney donation:

• BMI greater than 40 kg/m
• Active malignancy
• HIV positivity
• GFR less than 70 mL/min/1.72m,
• Albuminuria
• Hypertension requiring more than 1 medication
• Diabetes Mellitus
• Pelvic or horseshoe kidneys
• Psychiatric disorders

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Surgery

Transplant surgery always involves two surgeries, the donor and the recipient.

Implantation in the recipient is performed in an open fashion, where the kidney is placed heterotopically in the pelvis, anastomosing the vessels to the external iliac vessels and the ureter to the bladder.

Laparoscopic and/or robotic surgery is both considered minimally invasive and can be used to procure either kidney.

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Organ preservation

Once the kidneys are procured, they must be preserved before eventual implantation. During this process the kidneys experience ischemia.

Cold ischemia time begins as soon as normal perfusion stops and ends when the kidney is reperfused in its recipient – the kidney should be on the ice for as much of this time as possible to diminish metabolic demand and minimise injury.

Warm ischemia time is considered more harmful to the organ. It is classically described as the “sew-in” time when the organ is removed from cold storage until it is ultimately reperfused following vascular anastomosis.

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Complications of surgery

1. Haemorrhage – As with any vascular surgery, haemorrhage is always possible, both on the table and in the early postoperative period.
2. Thrombosis – Renal vein thrombosis is fortunately rare but is associated with a high risk of graft loss.
3. Infection – Infections are common as patients are placed on immunosuppression immediately postoperatively. They are most heavily immune-suppressed in the first 3-6 months post-operatively, putting them at heightened risk of infection during that window.
4. Patients are often placed on prophylactic antivirals and antibiotics to decrease the risk of infection in the first 3-6 months – most commonly Bactrim for PCP, Valcyte for CMV, as well as some form of anti-fungal coverage.
5. Arterial stenosis – This is a late complication and is often asymptomatic.

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Rejection

Renal transplant rejections can be classified broadly under the following categories:

1) Hyperacute rejection: This happens minutes after transplant, and it is related to the preformed antibody or ABO incompatibility; this is rarely seen now due to the very sensitive cross-match tests performed before the transplant.

2) Acute rejection: This can happen any time after the transplant, usually within days to weeks after the transplant. It classifies into the following:

1. Antibody-Mediated rejection
2. Acute T - Cell-mediated rejection

3) Chronic rejection: It usually develops more than three months post-transplant. It can either be chronic antibody-mediated rejection or chronic T cell-mediated rejection.

4) A mixture of acute rejection superimposed on chronic rejection.

Factors with an increased risk of rejection:

• Prior sensitisation - high panel reactive antibodies
• Type of transplant: A deceased donor has a higher rejection than a living transplant
• The advanced age of the donor
• Prolonged cold or warm ischemia time
• HLA mismatch
• Positive B cell crossmatch
• ABO incompatibility
• Recipient’s age: Younger recipients have more rejection than older ones
• Delayed graft function
• Therapy non-compliance
• Previous episodes of rejections
• Inadequate immunosuppression

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Recent advances

ABO-incompatible renal transplant: People of different blood groups can now also act as donors with the help of desensitisation and potent immunosuppression. However there mildly increased risk for infection and rejection.

Paired kidney exchange: In this living donor kidneys are swapped so each recipient receives a compatible transplant. There can be 2 ways or 3 ways or any number of swaps which helps in overcoming compatibility.

Disclaimer- The views and opinions expressed in this article are those of the author and do not necessarily reflect the official policy or position of M3 India.

About the author of this article: Dr Bhavin Mandowara is a practising nephrologist at Zydus Hospital, Ahmedabad.