Preoperative Troponin Levels and Outcomes of Coronary Surgery Following
Myocardial Infarction
Abstract
Background: This study evaluates the impact of peak preoperative
troponin level on outcomes of coronary artery bypass grafting (CABG) for
non-ST-elevation myocardial infarction (NSTEMI). Methods: This was a
retrospective review of patients undergoing isolated CABG from 2011-2018
with presentation of NSTEMI. Patients were stratified into low- and
high-risk groups based on median preoperative peak troponin (1.95ng/dL).
Major cardiac and cerebrovascular events (MACCE) and mortality were
compared. Multivariable analysis was performed to model risk factors for
MACCE and mortality. Results: This study included 1,211 patients, 607
low- (≤1.95ng/dL) and 604 high-risk (>1.95ng/dL). Patients
were well-matched with respect to age and comorbidity. High-risk
patients had lower median preoperative ejection fraction (46.5% [IQR
35.0%-55.0%] vs 53.0% [IQR 40.0%-58.0%]) and higher incidence
of preoperative intra-aortic balloon pump (15.9% vs 8.73%). Intensive
care unit (47 hours [IQR 26-82] vs 43 hours [IQR 25-69]) and
hospital lengths of stay (10 days [IQR 8-13] vs 9 days [IQR
8-12]) were longer in the high-risk group (each P<0.05).
Postoperative complications and thirty-day, one- and five-year rates of
both MACCE and survival were similar between groups. Peak troponin
>1.95ng/dL was not associated with increased hazards for
MACCE, mortality, or readmission in multivariable modeling. In
sub-analyses, neither increasing troponin as a continuous variable nor
peak troponin >10.00ng/mL were associated with increased
hazards for these outcomes. Conclusions: Higher preoperative troponin
levels are associated with longer lengths of stay but not MACCE or
mortality following CABG. Dictating timing of CABG for NSTEMI based on
peak troponin does not appear to be warranted.