Dobutamine stress echocardiography and the resting but not exercise electrocardiograph predict severe coronary artery disease in renal transplant candidates

Background. After renal transplantation half of all deaths are cardiac, so prior detection and treatment of severe coronary artery disease ( CAD) is advocated. The aim of this study was to identify non-invasive predictors of severe CAD in a group of renal transplant candidates. Methods. One hundred and twenty-five renal transplant candidates ( mean age 52 +/- 12 years, 80 male, mean creatinine 608 +/- 272 mmol/l) were studied. All had coronary angiography, dobutamine stress echocardiography, and resting and exercise electrocardiograph ( ECG). Severe CAD was defined as luminal stenosis > 70% by visual estimation in at least one epicardial artery. The resting ECG was recorded as abnormal if there was evidence of pathological Q waves, left ventricular hypertrophy, ST depression or elevation >= 1 mm, T wave inversion or bundle branch block. Total exercise time, maximal ST segment change, maximal heart rate and systolic blood pressure, limiting symptoms and Duke score were calculated during the exercise ECG test. Results. Of the patients, 36 ( 29%) had severe CAD, 55% were on dialysis and 39% were diabetic. Patients with severe CAD were significantly older ( P < 0.001), had higher total cholesterol ( P = 0.05), higher CRP level ( P 0.05), larger left ventricular (LV), end systolic and end diastolic diameter ( P = 0.007 for each), and lower LV ejection fraction ( P = 0.01). A significantly higher percentage were diabetic ( P = 0.05), had previous graft failure ( P 0.05), mitral annular calcification ( P = 0.04), an abnormal resting ECG ( P 0.001) and positive stress echo result ( P < 0.001). Cardiac symptoms and exercise ECG parameters were not significantly different in the two groups. Stepwise logistic regression identified an abnormal resting ECG ( OR 7, 95% CI 2, 34, P = 0.013) and positive stress echo result ( OR 23, 95% CI 6, 88, P < 0.001) as independent predictors of severe CAD. Conclusions. In selecting which potential renal transplant candidates should undergo coronary angiography, resting ECG and dobutamine stress echocardiography are the best predictors of severe CAD.