Long Term Predictors of Graft Patency After Coronary Artery Bypass Graft Surgery (Multi-slice CT Coronary Angiography Study Validated by Coronary Angiography)

Study Overview
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Brief Summary
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To detect and evaluate the predictors of graft patency after coronary artery bypass graft surgery as assessed by multi-slice CT coronary angiography validated by coronary angiography

Detailed Description
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Coronary artery bypass grafting (CABG) is an effective treatment of complex, multi-vessel coronary artery disease(1) .The majority of these patients receive left internal mammary artery (IMA) grafts to the left anterior descending (LAD) coronary artery and saphenous vein grafts (SVGs) or other conduits to the remaining vessels. Based on small studies of selected groups of patients, it is generally believed that SVGs have a 40% to 50% 10-year patency and that the LIMA has a 90% to 95% 10-year patency The success of coronary artery bypass grafting (CABG) is dependent on the long-term patency of the arterial and venous grafts.(2) Graft failure is a surrogate marker for future cardiac events, including repeat revascularization, myocardial infarction ,and death(3)(4). Vein graft occlusion in the perioperative period is due to thrombosis resulting from technical problems. Vein graft occlusion within the first year is attributed to intimal proliferation, although after 1 year, atherosclerosis is thought to be the dominant factor (5) . LIMA graft failure was defined as diffuse and >95% conduit narrowing (string sign When IMA graft failure occurs, technical error is the most common cause in the early postoperative period, while late (and rare) IMA failure include progressive fibro-intimal proliferation and atherosclerosis either in the IMA graft or in the native LAD vessel)(6) Traditionally, graft patency has been evaluated with coronary angiography (ICA) but, since the advent of multi-detector computed tomography (MDCT), the temptation to use a noninvasive and widely available technique to study coronary artery bypass graft (CABG) patients has been stronger. The introduction of scanners like 64-slice and 128-slice upwards-along with new scan protocols opens new perspectives in non-invasive assessment of graft patency.(7) The pooled sensitivity and specificity of detecting complete graft occlusions - according to( Barbero et al ,2016) ,was 99% and 99% respectively as compared to the standard of coronary angiography. (8) Computed tomographic angiography, labeled as Appropriate test for evaluation of bypass grafts and coronary anatomy (9)

Official Title
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Predictors of Long Term Graft Patency After Coronary Artery Bypass Graft Surgery (Multi-slice CT Coronary Angiography Study Validated by Coronary Angiography)

Conditions
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Coronary Artery Disease

Intervention / Treatment
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* Diagnostic Test: multi-slice CT coronary angiography and coronary angiography


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: All patients underwent coronary artery bypass graft surgery more than one year ago complaining of chest pain are included in the study from September 2017 to September 2018 Written consent, free and informed Exclusion Criteria: • Renal insufficiency (serum creatinine >1.6 mg/dl). Contrast hypersensitivity. Irregular heart rhythm (e.g. Atrial fibrillation). Inability to hold breath for at least 10 seconds

Ages Eligible for Study
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Minimum Age: 40 Years
Maximum Age: 80 Years

Sexes Eligible for Study
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All

Study Plan
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How is the study designed?
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Arms and Interventions

| Intervention/Treatment |
| --- |
|Diagnostic Test: multi-slice CT coronary angiography and coronary angiography|multi-slice CT coronary angiography to evaluate graft number and patency validated by coronary angiography|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| detection of predictors of long term graft patency following CABG | a. Primary (main): evaluation of long term predictors of graft patency following coronary artery bypass graft surgery Clinical risk factors e.g Age, gender, smoking, Diabetus mellitus, hypertension, Dyslipidemia, chronic kidney disease, congestive heart failure, medications especially antiplatelet and statin therapy, beta-blockers and calcium channel blockers . Biochemical risk factors e.g HDL, LDL, Total cholesterol level Angiographic risk factors : competitive flow and degree of stenosis in the native vessels. | 1 year | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Assessment of re-hospitalization rate following CABG |  | 1 year | 
| Relation between type of the graft and graft patency |  | 1 year | 
| Detection of sensitivity and specificity of CT coronary angiography for detection and assessment of graft patency |  | 1 year |