Effect of Aortic Clamping Strategy on Postoperative Stroke in Coronary Artery Bypass Grafting Operations

IMPORTANCE Aortic clamping technique has been implicated in stroke risk at the time of on-pump coronary artery bypass grafting (CABG) procedures. We hypothesized that partial aortic clamping (PAC) use in performing proximal coronary anastomosis does not increase risk of stroke. OBJECTIVE To determine whether postoperative stroke incidence is influenced by single aortic clamping (SAC) or side-biting PAC use in performing proximal anastomosis during CABG procedures. DESIGN, SETTING, AND PARTICIPANTS In a retrospective cohort study, we analyzed data from 1819 patients who underwent conventional, isolated, nonemergent, first-time, arrested-heart, on-pump CABG at a single US major academic, tertiary/quaternary medical center from January 1, 2005, to December 31, 2013. Postoperative stroke was defined according to Society of Thoracic Surgeons (STS) criteria as any confirmed neurological deficit of abrupt onset that did not resolve within 24 hours. Institutional STS data including STS predicted risk of postoperative stroke score were used to compare patients receiving proximal aortic anastomoses performed with either SAC (n = 1107) or combined PAC (n = 712) techniques. EXPOSURES Use of SAC or PAC in performing proximal coronary anastomosis. MAIN OUTCOMES AND MEASURES Thirty-day periprocedural postoperative stroke rates. RESULTS There were no significant differences in preoperative risk or STS predicted risk of mortality between groups. Patients in the SAC group had longer myocardial ischemic time compared with those in the PAC group (mean [SD], 73.2 [22.8] vs 66.5 [22.8] minutes, respectively; P < .001) but shorter overall perfusion time (mean [SD], 96.6 [30.1] vs 102.2 [30.1] minutes, respectively; P < .001). The 30-day observed mortality rates between the SAC and PAC groups were equally low (21 of 1107 patients [1.9%] vs 13 of 712 patients [1.8%], respectively; P > .99) and congruent with STS predicted risk of mortality. Preoperative STS predicted risk of postoperative stroke scores were nearly identical between the SAC and PAC groups (mean [SD], 1.5%[1.4%] vs 1.6%[1.4%]; P = .95), and the 30-day actual observed postoperative stroke rates between the SAC and PAC groups were similar (17 of 1107 patients [1.5%] vs 10 of 712 patients [1.4%], respectively; P > .99). CONCLUSIONS AND RELEVANCE In this contemporary study of on-pump CABG, we did not identify any significant differences in the incidence of postoperative stroke regardless of the clamping method used to perform proximal anastomosis.