Skeletonized vs Pedicled Internal Mammary Artery Graft Harvesting in Coronary Artery Bypass Surgery

Abstract

IMPORTANCEThe relative safety and patency of skeletonized vs pedicled internal mammary artery grafts in patients undergoing coronary artery bypass graft (CABG) surgery are unknown.OBJECTIVE To investigate the association of skeletonized vs pedicled harvesting with internal mammary artery graft patency and clinical outcomes 1 year after CABG surgery. DESIGN, SETTING, AND PARTICIPANTS This study was a post hoc analysis of the multicenter, randomized, double-blind, placebo-controlled Cardiovascular Outcomes for People Using Anticoagulation Strategies (COMPASS) clinical trial, which enrolled 27 395 patients from 602 centers in 33 countries from March 2013 through May 2016. Eligibility criteria for the trial included CABG surgery for coronary artery disease with at least 2 grafts implanted and an estimated glomerular filtration rate of at least 30 mL/min. A total of 1002 of 1448 patients were randomized to the CABG arm of the COMPASS trial and underwent skeletonized (282 [28.1%]) or pedicled (720 [71.9%]) internal mammary artery harvesting. The patients had evaluable angiography results 1 year after surgery. Data were analyzed from October 11, 2019, to May 14, 2020. INTERVENTIONS Patients underwent graft harvesting with either the pedicled technique or skeletonized technique. MAIN OUTCOMES AND MEASURES The primary outcome was graft occlusion 1 year after CABG surgery, as assessed by computed tomography angiography. RESULTS A total of 1002 patients underwent skeletonized (282 [28.1%]; mean [SD] age, 65.9 [8.1] years; 229 men [81.2%]; 194 White patients [68.8%]) or pedicled (720 [71.9%]; mean [SD] age, 64.8 [7.6] years; 603 men [83.8%]; 455 White patients [63.2%]) internal mammary artery harvesting. Rates of internal mammary artery graft occlusion 1 year after CABG surgery were higher in the skeletonized group than in the pedicled group (33 of 344 [9.6%] vs 30 of 764 [3.9%]; graft-level adjusted odds ratio, 2.41; 95% CI, 1.39-4.20; P = .002), including the left internal mammary artery to left anterior descending artery (21 of 289 [7.3%] vs 25 of 725 [3.4%]; graft-level adjusted odds ratio, 2.10; 95% CI, 1.14-3.88, P = .02). After a mean follow-up of 23 months, skeletonized graft harvesting was also associated with a higher rate of major adverse cardiovascular events (20 [7.1%] vs 15 [2.1%]; adjusted hazard ratio, 3.19; 95% CI, 1.53-6.67; P = .002) and repeated revascularization (14 [5.0%] vs 10 [1.4%]; adjusted hazard ratio, 2.75; 95% CI, 1.10-6.88; P = .03). CONCLUSIONS AND RELEVANCEThis post hoc analysis of the COMPASS randomized clinical trial found that harvesting of the internal mammary artery during CABG surgery using a skeletonized technique was associated with a higher rate of graft occlusion and worse clinical outcomes than the traditional pedicled technique. Future randomized clinical trials are needed to establish the safety and patency of the skeletonized technique.

Saphenous vein harvesting: A touchy subject

“…In a subgroup analysis of the CABG substudy of the randomized COMPASS trial (Xarelto ± aspirin vs. aspirin alone to reduce cardiovascular events in patients with coronary artery disease), use of a skeletonized ITA was associated with reduced 1-year patency and an increase in the rate of major adverse cardiovascular events including the need for repeat revascularization. 7 Other studies have failed to demonstrate similar angiographic results, and histological data suggest maintenance of endothelial integrity in skeletonized ITAs. 8,9 Although no imaging follow-up was included in the ART trial, it is logical to wonder whether a skeletonized technique may have led to an increased incidence of graft occlusion and diluted the potential effect of BITA grafting.…”

“…Although effective in reducing sternal wound complications compared with a pedicled technique, questions surrounding graft patency have recently arisen. In a subgroup analysis of the CABG substudy of the randomized COMPASS trial (Xarelto ± aspirin vs. aspirin alone to reduce cardiovascular events in patients with coronary artery disease), use of a skeletonized ITA was associated with reduced 1‐year patency and an increase in the rate of major adverse cardiovascular events including the need for repeat revascularization 7 . Other studies have failed to demonstrate similar angiographic results, and histological data suggest maintenance of endothelial integrity in skeletonized ITAs 8,9 .…”

Impact of left ventricular ejection fraction on outcomes after left main revascularization: g-LM Registry

“…In the CABG group, we utilized the pedicle technique more than the skeletonized method (81.5 and 18.5%, respectively) for harvesting LIMA conduits more frequently compared with the COMPASS trial (71.9 and 28.1%, respectively) 25 . Furthermore, our CABG patients had a higher rate of the open technique (61.5%) compared with the endoscopic vein method (38.5%) for SVG harvesting, which is similar to the ROOBY trial (62 and 38%, respectively) 26 .…”

Author Reply to Commentary: Conduit selection in the COMPASS trial: Pointing in the right direction

“…In the Cardiovascular Outcomes for People Using Anticoagulation Strategies coronary artery bypass graft (COMPASS-CABG) study, we were astonished to discover that skeletonization of the internal mammary artery (left internal mammary artery or RIMA), by experienced surgeons, rather than using a pedicle, was associated with poor patency and greater revascularization rate. 4 As the RIMA is frequently harvested with a skeletonization technique, the RIMA results were worse, and we hypothesize that the use of skeletonized RIMA was the reason for the poor performance of the bilateral internal mammary artery in the Arterial Revascularization Trial (ART), Dr Taggart's own trial. Our "alarming" manuscript was quickly followed by Dr Gaudino and colleagues in a post-hoc analysis of the ART, 5 proving our hypothesis was correct.…”