Comparative study of coronary collaterals in diabetic and nondiabetic patients by angiography

Myocardial ischaemia is known to be significantly related to the development of coronary collaterals, but there are considerable variations in their formation. The nature of this variability is not well understood. Likewise it remains unclear whether diabetes mellitus. DM has any effect on coronary collaterals. The aim of this study was to evaluate the effect of diabetes mellitus on coronary collaterals. This prospective case- control study was done from January to December 2000 in patients undergoing coronary angiography in National Institute of Cardiovascular Diseases (NICVD), Dhaka, who fulfilled the inclusion criteria of having < or = 75% stenosis in at least one coronary artery. The patients with diabetes having CAD without other modifiable major risk factors (hypertension, smoking, dyslipidaemia) were constituted case study group (n=36) and nondiabetic patients having CAD with those risk factors were constituted control group (n=50). Coronary collaterals were graded according to Rentrope scoring system and the collateral score was calculated by summing the Rentrope number of every patient. There was no statistical difference between patients with and without diabetes in clinical characteristics. The mean number of diseased vessel in DM group 2.6+/-0.6 was higher than that in nondiabetic patients (2.1+/-0.8, P>.05). The mean collateral score was 0.5+/-0.6 in DM group and 1.2+/-1.0 in nondiabetic group. These findings suggest that coronary collateral development is significantly poorer in diabetic than on diabetic patients.