Safety of internal thoracic artery use in patients with prior mediastinal radiation undergoing coronary artery bypass grafting: a Maryland statewide propensity-matched analysis.

Background: The safety of internal thoracic artery (ITA) grafting in patients undergoing coronary artery bypass grafting (CABG) with prior mediastinal radiation remains controversial due to concerns regarding compromised sternal perfusion and radiation-induced injury. This study evaluated whether prior mediastinal radiation is associated with adverse perioperative outcomes in patients undergoing CABG with ITA grafting.

Methods: We conducted a retrospective cohort study using the Maryland Cardiac Surgery Quality Initiative (MCSQI) database. A total of 29 206 patients who underwent CABG with ITA use between 1 July 2011 and 31 March 2023 were analysed. Patients with and without prior mediastinal radiation were propensity-matched (1:10) using the nearest neighbour method. The primary outcome was the composite of operative mortality and deep sternal wound infection (DSWI). Secondary outcomes included other infectious complications, major morbidities, postoperative hospital length of stay, and 30-day readmission.

Results: Among 29 206 patients, 294 (1%) had a history of mediastinal radiation. Patients with prior radiation were older (median (IQR) 70 (60-75) vs 66 (59-73) years, p<0.001), more frequently female (66% vs 25%, p<0.001) and had a higher prevalence of chronic lung disease (31% vs 19%, p<0.001). After propensity matching, no significant differences were observed in the primary composite outcome (2% vs 3%, p=0.53) or in secondary outcomes.

Conclusions: In this large retrospective cohort, prior mediastinal radiation was not associated with an increased risk of perioperative adverse events in patients undergoing CABG receiving ITA grafts. These findings demonstrate no evidence of safety concerns with the use of ITA grafting in patients with prior radiation and challenge the practice of excluding these patients from arterial revascularisation strategies.