Abstract 15813: Perioperative CK-MB Elevation is a Better Predictor of Survival Than New Q Waves Among Diabetic Patients With Multivessel Coronary Artery Disease Undergoing CABG
Background: Perioperative myocardial infarction (MI) worsens prognosis after coronary artery bypass grafting (CABG). Whether new Q waves or myocardial necrosis biomarker elevation is better to ascertain perioperative MI and determine subsequent prognosis is unknown.
Methods: We compared the prognostic significance of post-CABG CK-MB elevations to new Q waves in 689 FREEDOM patients with diabetes and multivessel coronary artery disease. Cox proportional-hazards regression was used to examine the relationship of cardiovascular (CV) mortality to post-procedure enzyme elevations (maximum CK-MB in the first 24 hours normalized by dividing by the individual laboratory upper limit of normal [ULN]), new Q waves (in first 48 hours or pre-discharge, whichever came first) and key baseline and perioperative patient characteristics. Stepwise regression was used for final model selection. Logistic regression was used to assess odds ratios for post-CABG new Q waves and CK-MB elevations.
Results: CK-MB elevations, but not new Q waves, were independently associated with survival time. Starting with CK-MB 7 times ULN, the HR becomes >2, and increases monotonically with threshold value selected (see Fig). There were 36 CV deaths (adjudicated by monitoring committee) reported for 689 patients (70% male, age at CABG 63±9 yr). In multivariable model the CV mortality was associated with CK-MB elevations (HR=1.06, p<0.001), female gender (HR=2.0, p=0.04), previous MI (HR=2.7, p=0.004), history of renal insufficiency (HR=3.1, p=0.02) and age (HR=1.05, p=0.02)
Conclusions: In patients with diabetes and multivessel coronary artery disease, p eak CK-MB in the first 24 hrs post-CABG, but not new Q waves, is significantly and independently associated with long-term survival. Female gender is an independent risk factor for reduced survival.
Figure: Hazard Ratio (with 95% CI) of CV death at CK-MB thresholds and the percentage of patients with new Q waves above each level of CK-MB
- © 2013 by American Heart Association, Inc.