Background and purpose: The combination of myocardial contrast echocardiography with dobutamine-atropine stress echocardiography has shown promising results in the diagnostic approach of coronary heart disease (CHD). However, its diagnostic value in specific patient populations has not been clearly specified. The aim of the present study was to assess the value of stress contrast echocardiography (SCE) in diagnosing significant coronary heart disease in diabetic versus non-diabetic patients.
Methods: 127 individuals (60 males, 62±9.8 years old) with no known history of CHD, among which 59 patients with Type 2 diabetes mellitus, were submitted to stress echocardiography (four-stage dobutamine protocol 10 – 40 mcg/kg/min, with use of atropine as required to reach 90% of age-adjusted target heart rate), combined with intravenous contrast use to perform myocardial contrast echocardiography. New or worsening wall motion abnormalities during stress or reversible perfusion defects in >2 contiguous segments were considered as signs of ischemia. Significant CHD was defined as >50% stenosis in a major epicardial artery on coronary angiography (CAG).
Results: Among the 68 non-diabetic subjects and the 59 diabetics, 58 (85.3%) and 45 (76.3%) were found to have significant CHD on CAG, respectively. There were no significant differences as regards to age, sex and other major risk factors between diabetics and non-diabetics. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) in the total of 127 patients were 92%, 63%, 91%, 65% and 87%, respectively. These diagnostic parameters in non-diabetic vs. diabetic subjects were 93% vs. 91% (p=
NS
), 90% vs. 43% (p<0.01), 98% vs. 84% (p<0.05) and 69% vs. 60% (p=
NS
).
Conclusions: Stress contrast echocardiography is an exceptionally reliable technique for CHD diagnosis. However, our findings suggest that in diabetic patients it appears to exhibit inferior specificity and PPV compared to non-diabetics. A possible explanation could be that microcirculation abnormalities, which are common in diabetes, may cause appearance of signs of ischemia (wall-motion abnormalities and/or perfusion defects) on SCE, without presence of angiographically significant CHD.
Clinical effect of atorvastatin-trimetazidine combined treatment of coronary heart disease
