Risk Factors for Deep Sternal Wound Infection after Off-Pump Coronary Artery Bypass Grafting: a Case-Control Study.

Introduction: The objective of this study was to identify risk factors for deep sternal wound infection (DSWI) after off-pump coronary artery bypass (OPCAB) grafting surgery.

Methods: A total of 8,442 patients undergoing OPCAB from April 1, 2009 to December 31, 2018 were retrospectively analyzed. A total of 956 were eventually enrolled on this study based on our exclusion criteria. All subjects were divided into two groups: group 1 (n=63) - DSWI; group 2 (n=893) - without DSWI. Patients were excluded if they had one of the following: acute coronary syndrome, conversion to OPCAB grafting surgery, redo procedure, concomitant cardiac surgery procedures.

Results: The prevalence of body mass index (BMI) ≥40 kg/m2 (7.9% vs. 1.9%, respectively; P=0.01), lower extremity atherosclerotic artery disease (23.8% vs. 7.2%, respectively; P=0.001) and use of bilateral internal thoracic artery (19.5% vs. 2.5%, respectively; P=0.008) was significantly higher in patients with DSWI. The incidence of morbidities, including reoperation for bleeding (26.4% vs. 2.1%, respectively; P<0.001), stroke (4.8% vs. 0.8%, respectively; P=0.02), acute renal failure (7.9% vs. 0.8%, respectively; P=0.001), delirium (7.9% vs. 1.7%, respectively; P=0.008) and blood transfusion (30.6% vs. 9.8%, respectively; P<0.001) was significantly higher in patients with DSWI.

Conclusions: A BMI of >40 kg/m2, lower extremity artery disease, use of bilateral internal thoracic artery (BITA) graft, postoperative stroke, sepsis, reoperation due to postoperative complications and blood product requirement significantly increased the risk of sternal infection after OPCAB.