1Universitäres Herz- und Gefäßzentrum Hamburg Klinik für Herz- und Gefäßchirurgie Hamburg, Deutschland
Objectives: Wound healing disorders (WHD) and in particular deep sternal wound infection (DSWI) remain a serious complication after coronary artery bypass grafting (CABG). We herein aimed to stratify diabetic patients who underwent CABG using BIMA for levels of glycated hemoglobin A1c (HbA1C) and compare postoperative outcomes.
Methods: Between 01/2010 and 08/2020, 4186 consecutive patients underwent isolated CABG at our center. In 3229 patients preoperative HbA1c levels were available. Primary endpoints were WHD, DSWI and 30-day mortality. Patients were divided into subgroups according to preoperative HbA1c levels (group 1: HbA1c˂6.5%, group 2: HbA1c≥6.5%).
Results: In unadjusted analysis patients with poor diabetic status presented with a higher rate of WHD (2.8 vs. 5.6%; p < 0.001) but not DSWI (1.0 vs. 1.5%; p=0.3). Group 2 also presented a higher mortality rate (0.9 vs. 2.1%, p=0.006), more frequent stroke (1.5 vs. 2.8%, p=0.037), more frequent renal failure (5.6 vs. 8.5%, p=0.025) and a prolonged postoperative ICU stay (2.52± 2.59 vs. 3.08± 5.60 days; p < 0.001). After adjustment no differences in mortality and stroke rates were seen between groups. WHD was more frequent in group 2 (2.8 vs. 5.6%; adjusted p = 0.002; adjusted OR 1.853 [1.243 - 2.711]) but not DSWI (1.0 vs. 1.5%; adjusted p = 0.543; adjusted OR 1.247 [0.612 - 2.5409). In patients with poor diabetic status a less frequent use of BIMA grafting was seen (60.3 vs. 55.5%; p = 0.016). BIMA use showed a higher rate of WHD (no BIMA: 3.0%; BIMA: 7.7%; adjusted p = 0.002; adjusted OR 4.766 (1.747 - 13.002)) but not DSWI (no BIMA: 1.1%; BIMA: 1.8%; adjusted p = 0.615; adjusted OR 1.591 (0.260 - 9.749)) in patients with HbA1c≥6.5%. When stratifying WHD/DSWI according to different levels of HbA1c a significant increase of WHD/DSWI was seen in patients with HbA1c >9% when compared to patients with HbA1c>6% (HbA1c 5-5.9 vs. >9%: WHD/DSWI 2.5 vs. 15%; p˂0.001; HbA1c 6-6.9 vs. >9%: WHD/DSWI 2.5 vs. 4.5%; p=0.01).
Conclusions: Intraoperative utilization of BIMA is not connected with an increase of DSWI but higher rates of WHD in patients with poor diabetic status and HbA1c≥6.5%. Therefore, application of BIMA may be taken into consideration even in patients with poor diabetic status, while identification of special subsets of patients which are at particular high risk for DSWI is of paramount importance to prevent this serious complication.