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To the Editor:

In her recent review on ‘Cardiac Assessment for Renal Transplantation’, Dr. Pilmore acknowledges the lack of clinical trial evidence for evaluating renal transplant candidates (1), and proposes an algorithm for preoperative testing that could result in tests and procedures with harmful side effects.

The bedrock approach to preoperative risk assessment is evaluation of the patient's risk profile, categorization of the surgery's risk and a testing/treatment strategy geared to protecting the patient. Table 1 in the article lists putative patient factors that would make a patient high risk (including diabetes, men > 45, women > 55, dialysis > 2 years and ‘LV dysfunction’). This list would designate the vast majority of renal transplant candidates as high risk. But Table 1 does not resemble the evidence-based clinical predictors published by the American College of Cardiology (ACC) in their guidelines for preoperative testing. Major clinical predictors from the ACC include recent myocardial infarction (MI), unstable angina, decompensated heart failure, severe valvular disease and serious arrhythmias. If these factors are absent, the patient should not be regarded as high risk. (Diabetes and renal insufficiency are among the intermediate predictors.) (2) As a procedure, renal transplant surgery is low to moderate risk (perioperative mortality should be <1% and morbidity should be <3% in good centers (3)). Thus, tests that predict a threefold increase in risk add little important information in preoperative risk stratification, when event rates are so low. The best perioperative treatment strategy for high-risk patients is beta adrenergic blockade (4).

As to cardiac testing, Pilmore conflates the distinct issues of preoperative risk assessment and long-term cardiac risks faced by renal transplant candidates. No debate exists as to whether renal transplant candidates are at a high risk for cardiac events long term; they are, and maximal medical therapy should be used. The consequence of Pilmore's testing approach, however, will be routine stress tests in asymptomatic transplant candidates. Tests will lead to angiographies, angiographies will find stenoses, and stenoses will lead to angioplasty and surgery, which have complications. Stenting >70% stenoses does not prevent most MI's, because MI's usually happen in nonflow limiting lesions. Stenting may also necessitate clopidogrel use, which increases bleeding risk and is regarded by some transplantation surgeons as a relative contraindication to surgery.

In the worst-case scenario, unnecessary cardiac testing could delay the most life-prolonging therapy for end-stage renal disease patients: renal transplantation. United States Renal Data Service data show that the adjusted 2-year survival for incident hemodialysis patients is 67%, with the majority of deaths cardiac. The adjusted 2-year survival rate for deceased donor transplant patients is 86%, and better with living donor allografts (5). Although the transplant patient population is not the same as the dialysis population, there is consensus that for appropriate candidates, renal transplantation decreases the risk for cardiovascular events by the first few years after surgery.

Dr. Pilmore correctly advocates for well-designed trials that specifically address cardiac risk in renal transplant candidates. Until that information arrives, we suggest that the ACC algorithm guide preoperative workup.

References

  1. Top of page
  2. References
  • 1
    Pilmore H. Cardiac assessment for renal transplantation. Am J Transplant 2006; 6: 659665.
  • 2
    Eagle KA, Berger PB, Calkins H et al. ACC/AHA guideline update for perioperative cardiovascular evaluation for noncardiac surgery–executive summary: A report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (committee to update the 1996 guidelines on perioperative cardiovascular evaluation for noncardiac surgery). J Am Coll Cardiol 2002; 39: 542553.
  • 3
    Davis CL. Evaluation of the living kidney donor: Current perspectives. Am J Kidney Dis 2004; 43: 508530.
  • 4
    ACC/AHA 2006 guideline update on perioperative cardiovascular evaluation for noncardiac surgery: Focused update on perioperative beta-blocker therapy. A report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Writing Committee to update the 2002 Guidelines on perioperative cardiovascular evaluation for noncardiac surgery). 2006. (Accessed on 6/2/2006 at http://www.acc.org/clinical/guidelines/perio/periobetablocker.pdf.)
  • 5
    Reference table: Patient survival. National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases , 2005. (Accessed on 6/2/2006 at http://www.usrds.org/2005/ref/I.pdf)