Medical Grand Rounds

Kidney transplant: New opportunities and challenges

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Release date: February 1, 2018
Expiration date: January 31, 2019
Estimated time of completion: 1 hour

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ABSTRACT

Progress in kidney transplant has improved survival while creating challenges. The pool of eligible patients is increasing, but organ supply remains inadequate. Waiting-list issues, adequate pretransplant assessment, judicious use of potent immunotherapy, and management of infections must be considered.

KEY POINTS

  • Kidney transplant improves survival and long-term outcomes in patients with renal failure.
  • Before transplant, patients should be carefully evaluated for cardiovascular and infectious disease risk.
  • Potent immunosuppression is required to maintain a successful kidney transplant.
  • After transplant, patients must be monitored for recurrent disease, side effects of immunosuppression, and opportunistic infections.


 

References

Much has improved in renal transplantation over the past 20 years. The focus has shifted to using stronger immunotherapy rather than trying to minimize it. There has been increasing recognition of infection and ways to prevent and treat it. Induction therapy now has greater emphasis so that maintenance therapy can be eased, with the aim of reducing long-term toxicity. Perhaps the biggest change is the practice of screening for donor-specific antibodies at the time of transplant so that predictable problems can be prevented or better handled if they occur. Such advances have helped patients directly and by extending the life of their transplanted organs.

LONGER SURVIVAL

As early as the 1990s, it was recognized that kidney transplant offers a survival advantage for patients with end-stage renal disease over maintenance on dialysis.1 Although the risk of death is higher immediately after transplant, within a few months it becomes much lower than for patients on dialysis. Survival varies according to the health of the patient and the quality of the transplanted organ.

In general, patients who obtain the greatest benefit from transplants in terms of years of life gained are those with diabetes, especially those who are younger. Those ages 20 to 39 live about 8 years on dialysis vs 25 years after transplant.

CONTRAINDICATIONS TO TRANSPLANT

Contraindications to solitary kidney transplant

There are multiple contraindications to a solitary kidney transplant (Table 1), including smoking. Most transplant centers require that smokers quit before transplant. Long-standing smokers almost double their risk of a cardiac event after transplant and double their rate of malignancy. Active smoking at the time of transplant is associated with twice the risk of death by 10 years after transplant compared with that of nonsmokers.2 Cotinine testing can detect whether a patient is an active smoker.

WAITING-LIST CONSIDERATIONS

Organs are scarce

The number of patients on the kidney waiting list has increased rapidly in the last few decades, while the number of transplants performed each year has remained about the same. In 2016, about 100,000 patients were on the list, but only about 19,000 transplants were performed.3 Wait times, especially for deceased-donor organs, have increased to about 6 years, varying by blood type and geographic region.

Waiting-list placement

Placement on the waiting list for a deceased-donor kidney transplant occurs when a patient has an estimated glomerular filtration rate (GFR) of 20 mL/min/1.73 m2 or less, although referral to the list can be made earlier. Early listing remains advantageous, as total time on the list will be counted before starting dialysis. “Preemptive transplant” means the patient had no dialysis before transplant; this applies to about 10% of transplant recipients. These patients tend to fare the best and are usually recipients of a living-donor organ.

Most patients do not receive a transplant until the GFR is less than 15 mL/min/1.73 m2.

Since 2014, wait time has been measured from the beginning of dialysis rather than the date of waiting-list placement in patients who are listed after starting dialysis therapy. This approach is more fair but sometimes introduces problems. A patient who did not previously know about the list may suddenly jump to the head of the line after 10 years of dialysis, by which time comorbidities associated with long-term dialysis make the patient less likely to gain as much benefit from a transplant as people lower on the list. Time on dialysis, or “dialysis vintage,” predicts patient and kidney survival after transplant, with reduced survival associated with increasing time on dialysis.4

Shorter wait for a suboptimal kidney

The aging population has increased the number of older patients being listed for transplant, presenting multiple challenges. Patients age 65 or older have a 50% chance of dying before they receive a transplant during a 5-year wait.

A patient may shorten the wait by joining the list for a suboptimal organ. All deceased-donor organs are given a Kidney Donor Profile Index score, which predicts the longevity of an organ after transplant. The score is determined by donor age, kidney function based on the serum creatinine at the time of death, and other donor factors.

A kidney with a score higher than 85% is likely to function longer than only 15% of available kidneys. Patients who receive a kidney with that score have a longer period of risk of death soon after transplant and a slightly higher risk of death in the long term than patients who receive a healthier kidney, although on average they still do better than patients on dialysis.5

Older patients should be encouraged to sign up for both the regular waiting list and the suboptimal kidney waiting list to reduce the risk of dying before they get a kidney.

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