(P175) AMI-PONT PROSPECTIVE RANDOMIZED CLINICAL TRIAL FOR ANTEROLATERAL TERRITORY CORONARY ARTERY BYPASS GRAFTING STRATEGIES

Background: The main objective of the AMI-PONT trial was to assess whether a CABG strategy including a bridge to distribute the LIMA outflow provides non-inferior patency rates compared to conventional CABG surgery with separated LIMA graft to LAD and aorto-coronary SVG to other anterolateral targets. The bridge grafting strategy uses a short SVG interposed between the LAD and at least one other anterolateral target, with the LIMA grafted on the hood of the bridge just above the LAD anastomosis (almost direct LIMA-LAD connection). This technique is easy to implement and has several potential advantages including distribution of LIMA flow to a greater vascular bed, bridge convenience for angioplasty, easier anastomosis of the smaller/fragile LIMA graft on the bridge compared to diseased/intramyocardial LAD targets, and use of shorter SVG.

METHODS AND RESULTS: The power analysis was based on a non-inferiority principle, considering the potential advantages of the bridge technique (unilateral 5% alpha, power 80%). From July 2012 to April 2021, 208 patients were randomized to a bridge (n=105) or conventional grafting strategy (n=103). Patients characteristics were comparable with a mean age of 65±8 years, 93% male, 34% diabetics, 22% recent myocardial infarction and LVEF of 57±9%. Patients underwent isolated CABG with cardiopulmonary bypass and received 4.2±0.9 grafts/patients including 2.2±0.4 grafts/patients on the anterolateral territory. There were three patient crossovers; data was assessed as intention-to-treat. The anterolateral graft patency index (i.e., non-occluded) was assessed using multislice spiral computed tomography at one year. The anterolateral graft patency index was no different at one year (bridge: 91.8% [145/158] vs conventional: 93.6% [160/171]) with a risk difference of 1.8% (90%CI -3.1% to 6.7%), which did not cross the specified boundary of -5%, demonstrating non-inferiority. The LIMA-to-LAD graft patency was no different (98.7% [74/75] vs 96.2% [75/78]; p=0.620). Intraoperatively, the bridge group exhibited greater Medistim doppler flow in the LIMA pedicle (75±48ml/min vs 56±33ml/min; p=0.002) and required shorter SVG length for the anterolateral targets (53±21mm vs 97±34mm; p<.001). The composite outcome of death, myocardial infarction or need for coronary intervention at 30 days was no different (2.9% [3/105] vs 6.8% [7/103]; p=0.212).

Conclusion: The AMI-PONT trial shows non-inferiority of a composite grafting strategy compared to conventional CABG strategy for anterolateral graft patency at one year. The LSVB grafting strategy presents several technical advantages for cardiac surgeons faced with an aging patient population with diffusely diseased target vessels, limited availability of suitable conduits and diseased ascending aortas. Ten-year clinical follow-up is planned.