DIAGNOSTIC-ACCURACY AND PROGNOSTIC VALUE OF COMBINED DIPYRIDAMOLE-EXERCISE THALLIUM IMAGING IN HEMODIALYSIS-PATIENTS

Background. Non-invasive detection of coronary artery disease in dialy sis patients, a major cause of mortality, often remains difficult. The aim of the study was to test the diagnostic and prognostic accuracies of combined dipyridamole-exercise thallium imaging in dialysis patien ts. Methods. Dipyridamole-exercise thallium imaging and coronary angio graphy were both performed prospectively in 60 asymptomatic hemodialys is patients who were followed up, long term, by recording any major co ronary event. Results. Coronary angiography was abnormal in 13 patient s (21%), and there was abnormal thallium uptake in 17 patients. Sensit ivity, specificity, positive and negative predictive values, and overa ll accuracy of thallium to detect a coronary artery disease were 92, 8 9, 71, 98 and 90%. respectively. After a median follow-up of 2.8 years , 12 patients experienced at least one major coronary event (4 cardiac deaths, 5 myocardial infarctions and 3 revascularizations). Eight of the 17 patients with abnormal thallium uptake (47%) suffered a coronar y event, compared to only 4 of the 43 patients (9%) with a normal thal lium uptake (P < 0.001). The positive prognostic predictive value of t hallium imaging was 47% and its negative predictive value was 91%. The probability of survival free of coronary events was significantly hig her in patients with normal thallium uptake than in those with abnorma l thallium uptake (crude risk ratio 7.6; P < 0.001) even after adjustm ent for several risk factors for cardiovacular disease (adjusted risk ratio 9.2; P < 0.005). Conclusion. In dialysis patients, combined dipy ridamole-exercise thallium imaging is an acurate method for detecting coronary stenosis and for predicting future coronary events.