EFFECT OF DIABETES MELLITUS ON GRAFT DISEASE PATTERN AFTER CORONARY ARTERY BYPASS GRAFT SURGERY IN SYMPTOMATIC PATIENTS DETECTED BY MULTI SLICE CORONARY COMPUTED TOMOGRAPHY ANGIOGRAPHY

Abstract

ABSTRACT Background: Surgical revascularization of the coronary arteries is one of the most frequent surgical procedures performed worldwide. Although the procedure is one of the major successes of modern medicine, it does not treat the disease underlying the symptoms (atherosclerosis), but only the clinical presentation of coronary artery disease. Multi detector computed tomography (MDCT) accuracy in coronary artery bypass grafting (CABG) patency and stenosis assessment is excellent compared with angiography. Its safety advantages have led to rapidly increasing usage in both native and grafted vessel evaluation. Objective: To evaluate the impact of diabetes mellitus on the patency of arterial and venous grafts after coronary artery bypass surgery assessed by multi slice CT coronary angiography. Patients and methods: One hundred post CABG patients were included, and divided into two groups: Group A (sixty diabetic patients) from which thirty two had NIDDM (53.3% of diabetic patients), twenty eight (46.6% of diabetic patients) had IDDM, and group B (forty non diabetic patients). Patients subjected to our study were symptomatic with recurrent typical chest pain or angina equivalent. All included patients had sinus rhythm, heart rate less than 70 bpm, weight less than 150 kg and serum creatinine <1.5 mg/dl. Patients were investigated by Seimens Somatom Definition Flash 64- dual source MDCT at least 12 months after the surgery. Results: The most common risk factor in our studied population was hypertension affecting 55% of studied population followed by smoking which was prevalent at 54% of studied population. Comparison of the number of diseased grafts in the two study groups according to hypertension showed a statistically significant difference in group A (diabetic group). Comparison of the number of diseased grafts in the two study groups according to dyslipidemia showed a statistically significant difference in group A. Comparison of the number of diseased grafts in the two study groups according to smoking showed a statistically significant difference in group B (non- diabetic group). 101 arterial grafts had been evaluated for patency, 96 LIMA and 5 radial arteries. There were 59 LIMA in diabetic patients and 37 LIMA in non-diabetic patients evaluated. There was no statistically significant LIMA occlusion in group A and group B. In our study, 141 venous grafts were evaluated for patency: 83 venous grafts in diabetic patients, and 58 venous grafts in non-diabetic patients. Comparison of the two study groups as regards patency of venous grafts showed a statistically significant in group A , and revealed also more occluded grafts at diabetic group. There was a statistically significant graft occlusion with longer duration of diabetes mellitus and higher glycosylated hemoglobin HbA1c. Conclusion: Multi-slice CT coronary angiography has an important role in evaluation patency of coronary grafts after coronary artery bypass surgery. Graft occlusions were more common among diabetics compared with non-diabetics. Diabetes was associated with lower vein graft patency but similar arterial graft patency in comparison to non-diabetics. Uncontrolled diabetes mellitus and long duration of disease was found to be a significant predictor for graft occlusion.