Cardiac Events in 735 Type 2 Diabetic Patients Who Underwent Screening for Unknown Asymptomatic Coronary Heart Disease

Abstract

OBJECTIVE -To report the cardiac events in type 2 diabetic outpatients screened for unknown asymptomatic coronary heart disease (CHD) and followed for 5 years.RESEARCH DESIGN AND METHODS -During 1993, 925 subjects aged 40 -65 years underwent an exercise treadmill test (ETT). If it was abnormal, the subjects then underwent an exercise scintigraphy. Of the 925 subjects, 735 were followed for 5 years and cardiac events were recorded.RESULTS -At the entry of the study, 638 of the 735 followed subjects had normal ETT, 45 had abnormal ETT with normal scintigraphy, and 52 had abnormal ETT and abnormal scintigraphy. The 52 subjects with abnormal scintigraphy and ETT underwent a cardiological and diabetological follow-up; the subjects with just abnormal ETT had a diabetological follow-up only. During the follow-ups, 42 cardiac events occurred: 1 fatal myocardial infarction (MI), 20 nonfatal MIs, and 10 cases of angina in the 638 subjects with normal ETT; 1 fatal MI in the 45 subjects with normal scintigraphy; and 1 fatal MI and 9 cases of angina in the 52 subjects with abnormal scintigraphy. In these 52 subjects all cardiac events were significantly more frequent ( 2 ϭ 21.40, P Ͻ 0.0001) but the ratio of major (cardiac death and MI) to minor (angina) cardiac events was significantly lower (P ϭ 0.002). Scintigraphy abnormality (hazard ratio 5.47; P Ͻ 0.001; 95% CI 2.43-12.29), diabetes duration (1.06; P ϭ 0.021; 1.008 -1.106), and diabetic retinopathy (2.371; P ϭ 0.036; 1.059 -5.307) were independent predictors of cardiac events on multivariate analysis. CONCLUSIONS -The low ratio of major to minor cardiac events in the positive scintigraphy group may suggest, although it does not prove, that the screening program followed by appropriate management was effective for the reduction of risk of major cardiac events.

Diabetic Retinopathy and the Risk of Coronary Heart Disease

“…Studies have shown that diabetic individuals with retinopathy are more likely to have myocardial perfusion defects (11,31,32), poorer coronary flow reserve (33), and lower coronary collateral score (34) than those without retinopathy. Moreover, diabetic retinopathy has also been associated with higher degrees of coronary calcification (35) and more diffuse and severe coronary artery stenosis on angiograms (36).…”

Detection of Silent Ischemia in Patients with Type 2 Diabetes

“…Silent ischemia was significantly related to future coronary events in asymptomatic diabetic patients after 2, 8 years (risk ratio: 21) (Rutter et al, 1999). Similarly, 5-year follow-up of the MISAD (Milan Study on Atherosclerosis and Diabetes) cohort showed that abnormal baseline scintigraphy was associated with fivefold increase in fatal and nonfatal cardiac events (risk ratio: 5,47) (Faglia et al, 2002). Diabetic patients with inducible ischemia on stress myocardial perfusion imaging using single-photon emission computed tomography (SPECT) have a significantly higher annual cardiac death or myocardial infarction rate than nondiabetic patients with ischemia (10% vs. 8%) (Shaw & Iskandrian, 2004).…”

“…Accordingly comparisons between myocardial perfusion imaging and stress echocardiography have shown a higher sensitivity for myocardial perfusion imaging for the detection of multivessel and single-vessel coronary artery disease (Schinkel et al, 2003). In asymptomatic diabetic patients the rate of silent myocardial ischemia diagnosed by stress myocardial perfusion imaging ranges from 6 to 59% (Zellweger et al, 2004;Faglia et al, 2002;, De Lorenzo et al, 2002;Wackers et al, 2004;Rajagapolan et al, 2005;Vanzetto et al, 1999;Cosson et al, 2004). This wide range in the prevalence of silent ischemia is related to differences in patient selection, stress methodology and imaging techniques.…”

“…In the Milan study on Atherosclerosis and Diabetes (MiSAD) asymptomatic patients with diabetes were first screened with exercise stress test and only if this test was abnormal stress myocardial perfusion imaging was performed. It is possible that because the low sensitivity of exercise ECG the overall observed prevalence of silent coronary artery disease was low 6% (Faglia et al, 2002). In DIAD (Detection of Ischemia in Asymptomatic Diabetics) a large prospective study, 1124 type 2 diabetic asymptomatic patients were enrolled.…”

“…Regarding the prognostic value of exercise stress test a study on 68 asymptomatic male veterans (Rubler et al, 1987) with diabetes mellitus found that exercise ECG testing had 50% sensitivity and 83% specificity for predicting subsequent cardiac events over an average of 41 months of follow-up. In the Milan study on Atherosclerosis and Diabetes (Faglia et al, 2002) 735 asymptomatic diabetic patients were screened for coronary artery disease and followed-up for 5 years. In all patients exercise ECG was performed with a positive test prompting stress nuclear testing.…”