| BACKGROUND:Type 2 diabetes mellitus (DM) is associated with a two to four fold increased incidence of coronary artery disease(CAD). The prognosis is worse in CAD patients with type 2 DM than in those without after whatever treatments including medical, percutaneous transluminal coronary angioplasty (PTCA) or bypass surgery. The question of whether the severity, extent or diffuseness of CAD is different in diabetic patients compared with non-diabetic subjects is controversial. Some early angiographic comparisons have suggested that patients with diabetes or impaired glucose tolerance have more triple-vessel CAD and less single-vessel CAD than those with normal glucose tolerance. Some autopsy studies reported that diabetic patients had a greater incidence of left main coronary artery stenosis and more extensive and diffuse disease compared with nondiabetic subjects. But it has been questioned in more recent studies. Waller found that the severity of CAD was the same between diabetic and non-diabetic patients. Hochman JS et al's autopsy study also demonstrated that CAD patients with DM had the same stenosis distribution in proximal, middle or distal vessels. Pia Pajunen suggested that CAD patients, with and without DM , who had similar symptoms at a given age, had similar severity and extent of CAD. Francois think that the situation ofCAD in mild DM patients (fasting glucose between 7nM/L and 7.7mM/L) is similar to non-diabetic patients. Most of these angiographic studies emphasized on the number of diseased vessels, like one-vessel disease, two-vessel disease and triple-vessel disease. Concerning the stenosis, generally only stenosis>70% was considered. This may bias the assessment of CAD, for it may underestimate the importance of those non-significant stenosis without rheology significance. Furthermore, many concepts are confused, especially the definition of diffuseness. Someone defined it as multi-vessel disease, someone defined it as a lesion >2cm, others also defined it as multi-lesions in one segment.The predictive factors of cardiac events after bypass surgery include age, preoperative left ventricular function, DM, cessation of smoking after bypass surgery, the number of diseased vessels, the classification of angina, hypertension, myocardial infarction history, renal failure, congestive heart failure, obesity and lack of using internal mammary artery. But anatomically, distal diffuse lesions or small vessel may theoretically restrict the blood flow, which predispose to stasis and thrombosis, resulting in both graft failure and vessel occlusion distal to the point of graft insertion. Even when the graft and the native artery remain patent, the ischemia caused by inadequate blood flow may predispose to recurrent angina, arrhythmia, congestive heart failure, re-intervention, myocardial infarction and cardiac death. The prognostic value of distal diftuseness score on cardiac event after bypass surgery has not been reported.OBJECTIVE:The present study seeks to show that the angiographic features of CAD with type 2 DM can be assessed by a structured quantificational reading of the coronary angiogram, especially distal difiuseness lesions, and that the distal difiuseness score predicts cardiac events after bypass surgery.METHODS:1. Patient selection:107 consecutive Isolated, non-emergency bypass surgery patients performed in Cardiac Science, National Guard Hospital, Saudi Arabia were included. 40 were non-diabetic, 67 were diabetic.Including criteria: Saudi nationality; Angiography were performed within 1 month before bypass surgery; isolated bypass surgery; first time bypass surgery; bypass surgery were performed under cardio-pulmonary bypass; at least one internal mammary artery was used.2. Data collection:(1)All demographic, CAD risk factors and clinical features of CAD were obtained from the database in Cardiac Science, which include nationality, gender, age, smoking, obesity, hyperlipidemia, DM, hypertention, classification of angina, heart function(NYHA) an...
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