Impact of pump status and conduit choice in coronary artery bypass: A 15-year follow-up study in 1412 propensity-matched patients

Abstract

Previous studies have demonstrated that bilateral internal mammary artery (BIMA) grafts lead to superior outcomes compared with single internal mammary artery grafts. This study examines whether cardiopulmonary bypass affects conduit-dependent outcomes of coronary artery bypass grafting (CABG) surgery. From 1994 to 2013, a total of 6666 patients underwent isolated CABG surgery at our institution. Of these procedures, 3548 (53.2%) were performed off pump. A BIMA-saphenous vein graft (SVG) was used in 1544, and 5122 had left internal mammary artery-SVGs. These 2 conduit groups differed significantly in baseline characteristics. Propensity matching based on 22 preoperative variables and using a nearest-neighbor matching algorithm was used to make balanced cohorts, resulting in 2 groups of 1006. To account for the influence of pump status on conduit selection, a second propensity score was developed for pump use. These cases were matched to create 4 patient cohorts of 353 patients each (a total of 1412), balanced for both conduit use and pump status. Late mortality was determined using the Social Security Death Index. No difference was found in survival between patients receiving BIMA-SVGs on or off pump (78.9% vs 79.1%). BIMA-SVGs outperformed the left internal mammary artery-SVGs regardless of whether the procedure was performed off pump (73.9%) or on pump (69.9%). This study demonstrates that the use of cardiopulmonary bypass does not significantly affect the long-term outcomes in these patients as long as full revascularization is achieved. In addition, these results are consistent with prior research showing that the use of BIMAs produces better outcomes than use of a single internal mammary artery when performing CABG.