Impact of Cholesterol Level on Long-term Coronary Bypass Graft Patency

Study Overview
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Brief Summary
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This single-centre cross-sectional study aims to ascertain the impact of dyslipidemia on long-term graft patency after coronary artery bypass grafting (CABG).

Detailed Description
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All consecutive patients who underwent CABG from 1st January 2007 to 31st December 2008 at the Prince of Wales Hospital were eligible for entry. Graft patency will be determined by computed tomography coronary angiogram. The severity of stenosis will be classified by the Fitzgibbon classification system. The levels of individual lipid profile subcomponents, namely LDL-C, high-density lipoprotein cholesterol (HDL-C), total cholesterol and triglycerides (TG) will be obtained. A plot of lipid profile subcomponent measurements against time will be compiled and the area under the curve is calculated to estimate gross exposure after CABG. Average lipid exposure is calculated by dividing the gross exposure by the number of days lapsed between the first and last lipid profile measurements. The association between average cholesterol target attainment and graft patency will then be determined.

Official Title
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Impact of Cholesterol Level on Long-term Angiographic Outcome of Coronary Artery Bypass Grafting

Conditions
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Coronary Artery Disease, Bypass Graft Stenosis, Dyslipidemias, Bypass Graft Occlusion, Coronary Bypass Graft Stenosis, Coronary Artery Stenosis, Hyperlipidemia, Hypercholesterolemia

Intervention / Treatment
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* Radiation: Computed tomography coronary angiogram


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: - All consecutive patients on record who underwent coronary artery bypass graft surgery in 2007 and 2008 Exclusion Criteria: Death Single vessel LIMA-LAD anastomosis only Concomitant valve and aortic procedures Concomitant repair of post-infarct ventricular septal rupture Defaulted follow-up Informed consent cannot be obtained Intermediate to high risk for contrast nephropathy, defined as estimated glomerular filtration rate less than 45 ml/min/1.73m2 or serum creatinine level <1.5 mg/dL (based on American College of Radiology criteria for diagnostic computed tomography risk) Pregnancy

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Intervention/Treatment |
| --- |
|Radiation: Computed tomography coronary angiogram|Preparation Rate control with oral beta-blockers or calcium channel blockers to achieve the target heart rate of 60 to 70 beats per minute Sublingual Nitroglycerin to be given on table if not contraindicated, 5 minutes prior to scanning 18G angiocath at a large antecubital vein for intravenous contrast injection Scanning procedure Contrast CT angiogram (Retrospective gating) Contrast medium and injection protocol: 75ml Omnipaque 350 with 50ml saline chaser Automatic triggering started at the aorta of the level of left main coronary artery when the relative reached 100 Scanning coverage: From the thoracic inlet to diaphragm|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Graft patency | Graft patency as assessed by computed tomographic coronary angiogram, using Fitzgibbon classification | Immediately after CTCA | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Actuarial cardiac events | Events attributable to cardiac causes as adjudicated by the investigators, including congestive heart failure, ischaemic cardiomyopathy, myocardial infarction, ventricular arrhythmias, recurrent angina | Immediately after CTCA | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Bypass graft failure, Dyslipidemia