Silent myocardial ischaemia (SMI) is frequent (50%) in diabetic patients (pts) under dialysis. Current guidelines recommend detection of SMI firstly by exercise stress testing (EST) and then by gated-single photon emission computed tomography (SPECT) or dobutamine stress echocardiography (DSE) when EST is impossible or inconclusive. Whether SPECT and DSE are equivalent in detecting SMI in diabetics under dialysis is unknown. The aim of this study was to assess the efficacy of these two tests compared to coronary angiography (angio) for the detection of SMI in this population.

Methods: 30 asymptomatic dialysed diabetic pts with normal resting ECG, aged 25-75 years were prospectively enrolled and submitted to exercise or dipyridamole SPECT, DSE and angio within 1 month. All investigations were interpreted blindly.

Results: At the time of this preliminary report, 24 pts had undergone all 3 investigations. They were mostly males (19M/5F) with type 2 diabetes (19/5); average age was 61 ± 10 years and known duration of diabetes was 15.8 ± 6.8years; BMI was 27 ± 4.7kg/m², and HbA1C was 6.8 ± 1.4%. Angio was abnormal (at least 1 stenosis? 70%) in 10 pts (42%); 4 pts had 1-vessel, 4 2-vessel and 2 had 3-vessel disease. Five pts underwent a revascularisation procedure (21%): coronary angioplasty with stenting in 4, coronary artery by-pass grafting in 1, both treatments in 1. No serious complication occurred during the procedures. SPECT detected 6 out of 10 stenoses (SPECT1) and 2 out of 5 stenoses in pts who needed a revascularisation procedure (SPECT2). DSE detected only 2 out of 10 stenoses (DSE1) and 1 out of 5 stenoses in revascularised pts (DSE2). The diagnostic value of both investigations is shown in the table. False negative results were mainly observed with both techniques in pts with 1-vessel disease.

Conclusions: This is the first evaluation of both SPECT and DSE in comparison to a systematic angio in asymptomatic diabetic dialysed pts. While DSE has an good specificity, its sensitivity is poor, leading to an unacceptable number of non-diagnosed stenoses. In contrast, SPECT has a slightly better sensitivity but a lower specificity, leading to numerous non useful coronary angiographies. Such non satisfactory results justify evaluating other non invasive techniques, such as coronary scan or MRI.