INCIDENCE OF CORONARY ARTERY DISEASE IN PROPENSITY MATCHED DIABETICS AND NON-DIABETICS USING MYOCARDIAL PERFUSION IMAGING AND ITS CORRELATION WITH CORONARY ANGIOGRAM

Abstract

BACKGROUND: Current guidelines consider diabetes per se as a coronary artery disease (CAD) risk equivalent. Myocardial Perfusion imaging (MPI) has been considered as a powerful non-invasive tool for diagnosing significant CAD. Aims of this study were to detect the incidence of CAD in propensity matched diabetics and non-diabetics by using MPI and to correlate perfusion abnormalities on MPI with coronary angiogram. MATERIAL & METHODS: Total 197 patients were included, 142 (72%) males and 55 (28%) were females, aged between 32 to 74 years (mean age = 58.5, median age =57 years). 92/197 diabetic patients were labeled as group A while remaining 105/197 nondiabetic were labeled as group B. Patients with prior myocardial infarction (MI) or revascularization were excluded. All included patients were subjected to MPI by using Tc99m Methoxy Isobutryl Isontrile (MIBI) with one day stress protocol. Coronary angiogram was done one month prior or after a positive MPS. RESULTS: Both groups were statistically similar in age, sex, weight and non-modifiable risk factor like positive family history of CAD. While hypertension and dyslipidemia was significantly higher in diabetics as compared to non-diabetics (83%:65% and 64%:36% respectively; p<0.05). The incidence of CAD as detected by perfusion defects on MPS was significantly higher in diabetics than non-diabetics (51% Vs 31%; p<0.05). Coronary angiography was available in 103/197 patients and calculated sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy in diabetics versus non-diabetics were 97.9%:84.6%, 44.4%:71.4%, 90.4%:94.3%, 80%:45.5% and 89.5%:82.6% respectively. Sensitivity and NPV was significantly higher in diabetics and specificity was higher in non-diabetics (p <0.05) while accuracy and PPV was statistically similar in both groups. In diabetics there was significantly higher ischemic burden (reversible perfusion defects 37% and transient ischemic dilation TID 18%; p<0.05) with predominance of multi-vessel involvement of 43% (p<0.05). CONCLUSIONS: The incidence of CAD on MPI is significantly higher in diabetic than propensity matched non-diabetics. MPI is more sensitive but less specific for CAD in diabetics but has a comparable accuracy for both groups. Diabetics are more prone to have significant higher ischemic burden than non-diabetics. Key words : Diabetes Mellitus; myocardial perfusion imaging; coronary angiography and coronary artery disease.