Hypertriglyceridaemia is associated with early non-patency of coronary bypass grafts

Abstract

C oronary artery bypass grafting (CABG) has prognostic benefit in patients with severe coronary disease and left ventricular dysfunction. It is particularly important in diabetic patients where CABG confers greater long term protection against coronary events than percutaneous angioplasty. However, up to 32% of saphenous vein grafts (SVGs) and 31% of radial artery grafts (RAGs) may be non-patent by one year.1 Hypertriglyceridaemia is associated with increased mortality after CABG, particularly among diabetics, but its relation to early graft patency is unknown.2 3 We investigated the association between metabolic risk factors and early graft occlusion by using non-invasive computed tomography (CT) angiography. METHODSThe study was approved by the institutional review board ethics committee. All patients attending a preoperative clinic for elective CABG between October 2002 and January 2004 in sinus rhythm with normal serum creatinine, but without a history of intravenous contrast allergy, were invited to participate. Written informed consent was obtained. Of 94 consecutive participants, 14 were subsequently excluded: two died postoperatively, one had a stroke, three developed renal impairment, and eight withdrew from the study.Recorded baseline characteristics were age, sex, history of smoking, hypertension (blood pressure . 140/90 mm Hg or pharmacological treatment for hypertension), hypercholesterolaemia (fasting cholesterol . 5.5 mmol/l or taking a cholesterol lowering agent), diabetes, and body mass index (BMI). Fasting preoperative total, low density lipoprotein, and high density lipoprotein cholesterol, triglycerides, glucose, insulin, C reactive protein, haemoglobin A 1c, fibrinogen, activated partial thromboplastin time, and white cell count were measured at a government certified laboratory. Insulin resistance and pancreatic b cell secretory capacity were calculated by means of the homeostasis model assessment for insulin resistance (HOMA-R) and for b cell function (HOMA-b), according to the formulas HOMA-R = fasting glucose (mmol/l) 6 fasting insulin (mU/l)/22.5, and HOMAb = fasting insulin (mU/l)/[fasting glucose (mmol/ l) 2 3.5]. 4 Graft patency was assessed by multislice computed tomographic (CT) angiography (Lightspeed Plus, GE Medical Systems, Waukesha, Wisconsin, USA) at 4-6 weeks postoperatively. Forty three patients were given oral metoprolol to achieve an average (SD) scan heart rate of 62 (9) beats/min. The scan parameters were 4 6 2.5 mm collimation, 1.3-1.5 pitch, 0.5 seconds rotation time, 120 kV, 270 mA, and 150 ml of intravenous non-ionic contrast medium (Ultravist 300, Schering AG, Berlin, Germany) at 3.5 ml/s. The mean breath hold was 27 seconds (range 22-32 s). Two analysers independently assessed each graft for patency (Card IQ, Advantage Workstation 4.0, GE Medical Systems) and, as there was complete agreement, consensus evaluations were not required. The reference diameter and the target native artery stenosis were measured from the preoperative conventional coronary angiograms by ...

Cardiovascular Risk Reduction is Important for Improving Patient and Graft Survival After Ligation and Bypass Surgery for Popliteal Artery Aneurysm

“…Reduced graft patency in patients with hyperlipidemia is almost certainly related to its effect on atherosclerosis. 21 Indeed, the detrimental impact of high cholesterol and triglyceride levels on early and late saphenous vein graft patency in patients undergoing coronary artery bypass grafting is well described, [22][23][24] and lipid-lowering medication has been shown to improve graft patency following both coronary artery and infrainguinal bypass grafting. 25,26 The influence of atherosclerotic risk factors on graft patency following bypass surgery for occlusive disease is described previously; however, this is the first time, to the authors' knowledge, that such risk factors have been quantified as the most important predictors of early graft failure following LGB surgery for aneurysmal disease.…”