Abstract 17725: Frequency and Prognostic Importance of Troponin and CK-MB Elevations Following Coronary Artery Bypass Grafting: An Analysis from PRIMO I and PRIMO II
Background: Perioperative myocardial infarctions (PMI) following coronary artery bypass grafting (CABG) are associated with increased mortality. PMI is often defined by postoperative elevations in cardiac biomarkers above an arbitrary threshold (5x or 10x the upper limit of normal [ULN]). Little data are available from systematic assessment of both CK-MB and troponin in CABG patients.
Methods: 7,234 patients undergoing CABG with or without valve surgery from the PRIMO I and II trials of pexelizumab were included. Serial CK-MB and troponin-I (cTnI) were collected through 96 hours post-CABG and analyzed by a core laboratory. Adjusted hazard ratios (HR) for 30-day mortality were calculated over a range of peak CK-MB and cTnI thresholds defined relative to the ULN.
Results: Perioperative CK-MB and cTnI data were available for 7050 (97.5%) and 6883 (95.2%) participants, respectively. The median (IQR) peak CK-MB and cTnI elevations were 6.1x ULN (3.9-10.8) and 21.0x ULN (10.3-52.6), respectively. The figure shows the adjusted 30-day mortality HR (95% CI) for CK-MB and cTnI at thresholds ranging from 2-40x ULN. CK-MB elevations of 5, 10, 20, and 40x ULN were associated with an adjusted 30-day mortality HR (95% CI) of 2.89 (1.92-4.35), 2.46 (1.81-3.34), 4.07 (2.97-5.59), and 6.06 (4.12-8.90), respectively. The corresponding adjusted 30-day mortality HR for cTnI were 2.61 (0.96-7.13), 2.80 (1.59-4.91), 2.81 (1.90-4.14), and 3.12 (2.24-4.36).
Conclusion: Elevations in CK-MB and cTnI following CABG are common and independently associated with 30-day mortality across the entire range of thresholds studied. For comparable CK-MB and cTnI elevations, CK-MB elevations are associated with a higher hazard for 30-day mortality. These data have important implications in the design of clinical trials in CABG populations and the biomarker criteria used in PMI definitions. Future work will investigate the additive information provided by other clinical data such as ECG changes.
- © 2012 by American Heart Association, Inc.