Prognostic Value Of Normal Myocardial Perfusion Imaging In Asymptomatic Diabetic Patients With Moderate And High Calcium Scores

The purpose of this study was to evaluate the intermediate prognostic value of normal myocardial perfusion imaging (MPI) in asymptomatic diabetic patients with intermediate and high coronary artery calcium (CAC) scores. Methods: A total of 115 asymptomatic diabetic patients with no known coronary artery disease (CAD) underwent MPI after multi-slice computed tomography CAC assessment for the detection of suspected CAD. The study included 75 patients with normal MPI results. A 17-segment model for myocardial perfusion and function analysis was used. Patients were divided into three groups: I gr-20 patients with a diabetes duration between 1-5 years; II gr-24 patients with a diabetes duration 5-10 years; and III gr-31 patients with a diabetes duration >10 years. End points (cardiac death, non-fatal myocardial infarction, heart failure, new angina, revascularization) were assessed at 6, 12 and 24 months.

All patients had normal resting left ventricular function and normal myocardial perfusion scans. Forty patients had moderate coronary artery calcification with an average CAC of 290+/−95. Thirty-five patients had severe coronary calcification with an average CAC of 568+/−67. A correlation was found between diabetes duration and CAC severity (r-0,62 for diabetes duration over 10 years). Three cardiac events were identified at 24--month follow-up (new angina with percutaneous coronary intervention-PCI). Hard events (cardiac death, nonfatal myocardial infarction) were observed at a rate of 0% in group I, 4.2% in group II and 6.4% in group III. The overall event rate at 24--month follow-up was 4.0%.

MPI and CAC are valuable techniques for the preclinical assessment of CAD in asymptomatic diabetic patients. This could guide decision-making to result in optimal treatment and prognosis. Even diabetic patients with normal MPI are at increased intermediate risk for CV events.