Coronary Artery Bypass Grafting Strategies for the Anterolateral Territory: a Prospective Randomized Clinical Trial

The purpose of the AMI-PONT trial is to assess whether the results in term of graft patency with a novel coronary artery bypass (CABG) strategy, including a saphenous vein bridge to distribute the arterial flow of the left anterior mammary artery (LIMA) to all the anterolateral territory, are not inferior than a conventional CABG strategy combining separated LIMA graft to left anterior descending coronary and vein graft for other target vessels of the anterolateral territory.

Purpose: This novel surgical design use a composite-sequential venous graft to distribute left anterior mammary artery (LIMA) inflow directly to the left anterior descending coronary (LAD), but also to the other branches of the anterolateral territory thereby promoting a higher flow through the LIMA pedicle. It is constructed using a short saphenous vein graft (SVG) bridge (LSVB) interposed between the LAD and one (or more) other anterolateral targets, with the LIMA grafted on the hood of the SVG just above the LAD anastomosis.

Objectives. The main objective of the prospective randomized clinical trial AMI-PONT is to assess whether a CABG strategy including a LSVB to distribute the LIMA outflow provides non-inferior patency rates compared to conventional CABG surgery with separated LIMA graft to LAD and SVG to other anterolateral targets.

Methods. Two hundred adult patients undergoing primary isolated CABG, requiring grafting of LAD and at least one other anterolateral target, will be randomized 1:1 in two treatment arms: 1) CABG strategy with LSVB; and 2) conventional CABG strategy with LIMA graft to the LAD and separate aorto-coronary SVG to other anterolateral targets. Patients will be assessed clinically at 30 days, 6 months, one, five and ten years. They will undergo graft patency assessment at one and five years using Multi-Slice Computed Tomography. All patients will undergo CABG using cardiopulmonary bypass (CPB). Patients will be excluded if they have a contraindication to CPB or MSCT graft assessment.

Eligibility Criteria:
Inclusion Criteria: Patients who undergo coronary artery bypass grafting (CABG) surgery (for single, double or triple vessel disease) will be eligible if they:

1. require isolated CABG with median sternotomy on at least one left anterior descending (LAD) site and another anterolateral target;
2. provide written informed consent;
3. are more than 21 years of age.

Exclusion Criteria: A patient will be excluded from the study if he/she does not fulfill the inclusion criteria, the patient or the treating physician refuse the study or if any of the following are observed:

1. concomitant cardiac procedure associated with CABG including valve surgery and ascending aorta surgery;
2. contra-indications to cardiopulmonary bypass (calcified aorta);
3. unusable left internal mammary artery (LIMA) such as uncorrected subclavian artery stenosis, anterior chest trauma, radiation or injury during harvesting precluding the use of the LIMA;
4. concomitant life-threatening disease likely to limit life expectancy to less than 2 years;
5. emergency CABG surgery (immediate revascularization for hemodynamic instability precluding patient consent);
6. prior CABG;
7. severe congestive heart failure with left ventricular ejection fraction less than 30%.

   Other exclusion criteria precluding MSCT include:
8. moderate to severe renal impairment (estimated glomerular filtration rate, eGFR \<50 mL/min/1.73 m2);
9. chronic atrial fibrillation (which can preclude ECG-gating during MSCT);
10. history of severe hypersensitivity to iodinated contrast agents;
11. known or suspected for pheochromocytoma;
12. pregnant/lactating female.

    Furthermore, patients may be excluded at the time of MSCT if they are:
13. in persistent rapid (\>100/min) atrial fibrillation or any other cardiac rhythm that precludes reliable ECG triggering;
14. severe congestive heart failure, New York Heart Association (NYHA) Class IV, despite coronary revascularization and maximal medical treatment.