Postoperative Insulin Dose for Cardiac Artery Bypass Graft and Other Cardiac Surgeries in Patients with Type 2 Diabetes: A Retrospective Study.

Purpose: Recommendations on perioperative glycemic control in cardiac surgery are based on coronary artery bypass graft surgery (CABG), though coronary artery disease and valvular disease are pathologically distinct. We aimed to compare the postoperative insulin requirement between CABG and other cardiac surgeries in type 2 diabetic patients and identify predictive factors for the maximum postoperative insulin dose.

Patients and methods: We retrospectively included 60 Japanese patients with diabetes/glucose intolerance (HbA1c > 37 mmol/mol [5.6%]) who were hospitalized for cardiovascular surgery between April 2017 and March 2019. We categorized the subjects into the CABG and non-CABG groups, and performed subgroup analysis on patients who received postoperative insulin therapy.

Results: The CABG group required a significantly higher insulin dose on postoperative days 2, 5, 6, and 7, and a significantly higher maximum postoperative insulin dose (24.6 U vs 9.7 U, P < 0.001) than the non-CABG group. Multivariate linear regression analyses showed that the independent determinants of the maximum postoperative insulin dose were HbA1c and duration of diabetes in the non-CABG group, and HbA1c in the CABG group.

Conclusion: CABG had a higher postoperative insulin requirement than other cardiovascular surgeries; early aggressive insulin therapy is indicated, especially for patients with higher HbA1c levels/longer duration of diabetes.