Study objective: To assess the impact of intraoperative hemodynamics in the development of perioperative myocardial infarction (MI) and myocardial ischemia after noncardiac surgery.
Design: Single-center retrospective cohort study of surgical patients from 2007 to 2012.
Setting: Postanesthesia care unit, intensive care unit, and medical-surgical ward at an academic tertiary medical center.
Patients: A total of 46,799 adult noncardiac, nonthoracic surgery patients, for which 2290 peak cardiac troponin (cTn) levels were available.
Measurements: The 10-point Surgical Apgar Score (SAS) was calculated from intraoperative heart rate, blood pressure, and blood loss. Peak troponin (cTn) levels, hospital length of stay, 7- and 30-day postoperative mortality, patient demographics, and prior medical conditions were gathered. Troponin leak was defined as cTn-I 0.6 to 1.5 ng/mL or cTn-T 0.1 to 0.3 ng/mL; perioperative MI criteria were cTn-I greater than 1.5 ng/mL or cTn-T greater than 0.30 ng/mL.
Main results: Of 46,799 noncardiac surgical cases, 209 (0.4%) and 192 (0.4%) suffered cTn leak and MI, respectively. Low SAS (0-4) was associated with increased risk of cTn leak and perioperative MI (univariate odds ratio, 2.76 and 2.06; 95% confidence interval, 2.20-3.45 and 1.57-2.70, respectively). In multivariable analysis, Surgical Apgar Score, age 65 years or older, American Society of Anesthesiologists physical status greater than or equal to III, emergency surgery, history of MI or hypertension, prolonged intraoperative tachycardia (heart rate >100 beats/min for >59 minutes), and prolonged hypotension (mean arterial pressure <40 mm Hg for >2 minutes) were independently associated with cTn leak and perioperative MI.
Conclusions: Low SAS scores (0-4) may be associated with cTn elevation after noncardiac surgery. SAS-based risk stratification may guide perioperative cTn surveillance in lieu of routine postoperative screening.
Keywords: Ischemia; Myocardial injury; Non-cardiac surgery; Perioperative myocardial infarction; Surgical Apgar Score; Troponin elevation.
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