Complications after kidney transplantation

part 1

Course topicsPart 1• Urological complications after kidney transplantation• Cardiovascular complications• Infection in renal transplant recipientsPart2• Vascular complications• Liver disease in renal transplant recipients• Neurological complications• Nonmalignant and malignant skin lesions in renal

transplant patients

Urological complications after kidney transplantation

• Ureteral Complications- Ureteral Leak-Ureteral Stenosis

• Use of Prophylactic Ureteral Stents• Urinary Retention• Erectile Dysfunction

• Ureteral leak or obstruction is typically caused by either technical errors or ischemia.

• The native ureter derives its blood supply from renal and pelvic sources, but the transplant ureter must rely on branches from the anastomosed renal artery.

• The ureter becomes more ischemic the more distal it is from the kidney.

• One of the advantages of placing a renal allograft into the pelvis is the short distance to the bladder - it allows a minimal length of transplant ureteral length.

• The other surgical principle to ensure optimal ureteral perfusion is preservation of the blood supply.

• This is accomplished during procurement by removing theureter complete with a significant margin of periureteral tissue, avoiding a “stripped” ureter

• During the back table preparation of the kidney, it is important to preserve the perirenal fat bordered by the ureter and lower pole of the kidney (the “golden triangle”)

Ureteral Leak• Ureteral leaks are reported in 1% to 3% of renal transplants.• The two most common causes are ureteral ischemia with necrosis and surgical technical error. • Technical errors include misplacement of ureteral sutures

and insufficient ureteral length with tension on the anastomosis.

• Leaks resulting from technical errors often occur within the first 24 hours, whereas leaks from necrosis usually occur within the first 14 days.

Ureteral leak – repair techniques

Psoas hitch and Boari flap techniques

• Ureteral Stenosis• Stenosis of the transplant ureter occurs in

approximately 3% of transplant recipients.• The obstruction can be extraluminal

(compression from lymphocele or spermatic cord), ureteral (ischemia), or intraluminal (stone, fungal ball, sloughed renal papilla, foreign body).

• Ureteral stenosis may occur months or years after an otherwise successful transplant.

• Most commonly, ureteral stenosis is gradual and asymptomatic, with an unexplained increase in creatinine leading to discovery of hydronephrosis on ultrasound or computed tomography

• Stents can reduce the incidence of ureteral leaks and early ureteral stenosis and make the early management of leaks easier.

URINARY RETENTION• After renal transplantation, urinary retention may be

due to bladder outflow obstruction or a neurogenic noncontractile bladder.

• Bladder outflow obstruction after transplantation is almost exclusively seen in men and may be due to urethral stricture, benign prostatic hypertrophy, or bladder neck contracture

• Patients with a noncontractile bladder usually have a preexisting history of voiding problems or neurological disorders ( Parkinson’s disease, multiple sclerosis, diabetes with peripheral neuropathy)

ERECTILE DYSFUNCTION

• With an aging transplant population, erectile dysfunction is a prevalent and increasingly identified problem.

• Factors contributing to erectile dysfunction are often the same factors responsible for renal failure, including diabetes, hypertension (and its medical treatment),and vasculopathy.

• Dialysis patients may have elevated serum prolactin, which can depress testosterone and lead to erectile dysfunction; this may explain partly the 20% of patients whose erectile dysfunction improves after transplant.

• The use of internal iliac artery for anastomosis should be avoided in men receiving a second transplant, in whom vasculogenic impotence can occur as a result in 25%.

Cardiovascular complications

Pretransplant Measures to Reduce Cardiovascular Disease

• Screening for Ischemic Heart Disease before Transplantation

• Perioperative β Blockade

Post-Transplant Measures to Reduce Cardiovascular Disease

• Prophylactic Anticoagulation• Aspirin Prophylaxis• Cigarette Abstinence• Hypertension treatment• Dyslipidemias control• Diabetes treatment• Antioxidant Vitamins

Infection in renal transplant recipients

• Transplant recipients are susceptible to a broad spectrum of infectious pathogens, manifest diminished signs and symptoms of invasive infection, and may develop systemic signs (e.g., fever) in response to noninfectious processes (e.g., graft rejection, drug toxicity) with multiple processes often present.

• Immunocompromised patients tolerate invasive, established infection poorly with high morbidity and mortality, lending urgency to the need for an early, specific diagnosis to guide antimicrobial therapy

• Given the T lymphocyte dysfunction inherent to transplantation immunosuppression, viral infections in particular are increased.

• These viral infections not only contribute to graft dysfunction, graft rejection, and systemic illness but also enhance the risk for other opportunistic infections (e.g., Pneumocystis and Aspergillus) and virally mediated cancers

• The risk of infection in a renal transplant recipient is determined by the interaction of two key factors:

1. The epidemiological exposures of the patient, including the timing, intensity, and virulence of the organisms

2. The patient’s “net state of immunosuppression” which reflects a measure of all host factors

contributing to the risk for infection

Factors contributing to the net state of immunosupression

The timeline of infection after transplantation