Identifying patients at particular risk of injury during repeat sternotomy: Analysis of 2555 cardiac reoperations

Objectives: A variety of protective strategies during repeat sternotomy been proposed; however, it remains unclear for which patients they are warranted. Methods: We identified adults undergoing repeat median sternotomy for routine cardiac surgery at our institution between January 1, 1996, and December 31, 2007. The operative notes and perioperative outcomes were reviewed. Results: Of the 2555 patients, 1537 (60%) had undergone previous coronary artery bypass grafting, 700 (27%) previous mitral valve surgery, and 643 (25%) previous aortic valve replacement (AVR). Sixty-one patients (2%) had prior mediastinal radiotherapy, and 424 (17%) had more than one previous sternotomy. In 231 patients, 267 injuries (9.0%) occurred. Injury occurred during sternotomy in 87 patients (33%) and during prepump dissection in 135 (51%). The hospital mortality rate was 6.5% among those without injury and 18.5% among those with injury (P < .001); when injury occurred during sternal division, the mortality rate was 25%. Injuries were more common after previous coronary artery bypass grafting (11% with previous coronary artery bypass grafting vs 7% without, P = .0012) but not previous AVR, mitral valve surgery, or aortic surgery. Injury was also more common when the current operation was AVR (10% with AVR vs 8% without, P = .04) or aortic surgery (14% vs 8%, P = .004). On multivariate analysis, previous radiotherapy (odds ratio, 4.9), a greater number of previous sternotomies (odds ratio 1.7), and a patent internal thoracic artery (odds ratio, 1.8) predicted injury. Injury was an independent risk factor of hospital death (odds ratio, 2.6). Conclusions: Particular attention to protective strategies should be considered during reoperative sternotomy among patients with multiple previous sternotomies, previous mediastinal radiotherapy, and those with patent internal thoracic artery grafts.