Should We Do Cardiac Stress Tests in Asymptomatic Renal Transplant Candidates?

Abstract

Background: Although the high burden of coronary artery disease in the dialysis population, the expected benefit of screening tests in asymptomatic renal transplant candidates is a controversial topic. Recently, we found that the rates of noninvasive stress testing(stress echocardiogram, or nuclear stress test) range from 20 to 100% depending on which renal specific transplant guidelines(KDOQI, AST, and Lisbon) were applied. Interestingly the positive predictive value of ischemia on noninvasive stress test is about 5% -10% in KDOQI, AST, and Lisbon guidelines. Noninvasive stress tests are more expensive and able to trigger ischemia, and arrhythmia than conventional trans thoracic echocardiography(TTE). We compared episodes of patient death with heart disease, and ischemic heart disease Methods: Kidney transplant candidates who recommended stress test according to the guidelines (KDOQI and AST) were enrolled. Although they had multiple risk factors, they had a good ordinary activity and no symptoms. All of patients were performed TTE and selected that did not show any regional wall motion abnormality, severe valvular disease, and abnormal ejection fraction. 165 paitents were enrolled and divided into two groups. A group underwent only TTE (N=124) and B group underwent TTE with noninvasive stress test (n=41). We measured incidence of patient death with heart disease, and symptomatic ischemic heart disease within 3 years after kidney transplantation. Results: The mean age of group A was 39 ±7 years, and B group was 40 ±5 years. Diabetes patients of group A and B were consisted of 8.8%(11/124) and 9.7% (4/41), respectively. Only 4 patients of group B had a positive result on noninvasive stress test but they had no obstructive coronary disease on coronary angiograms. The total incidence of ischemic heart disease of group A and B were 6.4% (8/124) and 7.3% (3/41), respectively. There was no patient in both groups who death with primary heart problems within 3 years after kidney transplantation. Conclusion: Conventional TTE has a similar effect to predict ischemic heart disease in asymptomatic candidates who are relatively young, and have a good physical functional copacity. Renal transplant specific guidelines recommend widespread pretransplant cardiac test. Therefore we need prospective studies that compare screening tests and their associated clinical outcomes to find proper application of diagnostic strategies in kidney transplant candidates.