Abstract 17855: Risk Factors For 30-Day Outcome Following Multivessel Bypass Surgery in Diabetic Patients With Stable CAD: Pre-Operative Glycemic Control and Blood Pressure Management Matter
Background: Diabetic patients with multi-vessel coronary artery disease (CAD) undergoing coronary artery bypass grafting (CABG) surgery are at increased risk for poor 30-day post-operative outcomes. We sought to identify modifiable risk factors that could affect outcome with focus on systolic blood pressure (SBP), low density lipoprotein cholesterol (LDL-C), hemoglobin A1c (HbA1c) and cardiac surgical techniques.
Methods: We analyzed the 30d post-procedure composite outcome (death/stroke/myocardial infarction) in FREEDOM trial subjects who underwent CABG to treat multivessel CAD. We used generalized additive modeling and logistic regression to determine if baseline exam SBP, LDL-C and HbA1c were independent risk factors in addition to demographic, medical history, and cardiac surgical technique variables. We defined low SBP as <120 mmHg (HYPO; 18%); moderate SBP as 120 to <160 mmHg (MedSBP; 72%), and high SBP as ≥160 mmHg (HighSBP; 11%).
Results: In 898 patients undergoing CABG (63±9 yr, 70% men, HbA1c 7.8±1.7%, 31% on insulin, SYNTAX 26±9), there were 56 events at 30d post-procedure (22 deaths, 18 MI, 16 stroke). SBP was nonlinearly related to outcome (nonlin p=0.02) with lowest risk (4.6% of patients) for those with MedSBP and an event in 8.1% of HYPO and 11.4% of HighSBP patients. Stroke comprised 39%, 28%, and 18% of events in the HYPO, MedSBP, HighSBP groups, respectively. In a multivariable model (N=892), SBP remained marginally significant (p=0.057, 2 df) in the presence of HbA1c (hazard ratio [HR] 1.23, 95% CI 1.04-1.47, p=0.02), age<65 yrs (HR 0.39, 95% CI 0.20-0.76, p=0.005), heart rate (HR 1.35, 95% CI 1.04-1.73 per 10 bpm, p=0.02) and the use of crystalloid cardioplegia alone during bypass (HR 2.28, 95% CI 1.09-4.76). The HR for HYPO vs. MedSBP was 1.58 (95% CI 0.71-3.51) and HighSBP vs. MedSBP was 2.51 (95% CI 1.11-5.69).
Conclusions: Higher HbA1c is independently associated with worse 30d surgical outcome in diabetic patients. Both HYPO and HighSBP impart a 2-fold risk for 30-day death/stroke/MI. Judicious medical management prior to surgery to control HbA1c and SBP is warranted to optimize 30d outcomes in stable diabetic patients undergoing CABG.
- © 2013 by American Heart Association, Inc.