Adverse cardiac events after surgery - Assessing risk in a veteran population

OBJECTIVE: To establish rates of and risk factors for cardiac complications after noncardiac surgery in veterans. DESIGN. Prospective cohort study. SETTING: A large urban veterans affairs hospital. PARTICIPANTS: One thousand patients with known or suspected cardiac problem s undergoing 1,121 noncardiac procedures. MEASUREMENTS: Patients were assessed preoperatively for important clinical variables. Postoperative evaluation was done by an assessor blinded to preo perative status with a daily physical examination, electrocardiogram, and c reatine kinase with MB fraction until postoperative day 6, day of discharge , death, or reoperation (whichever occurred earliest). Serial electrocardio grams, enzymes, and chest radiographs were obtained as indicated. Severe ca rdiac complications included cardiac death, cardiac arrest, myocardial infa rction, ventricular tachycardia, and fibrillation and pulmonary edema. Seri ous cardiac complications included the above, heart failure, and unstable a ngina. MAIN RESULTS: Severe and serious complications were seen in 24% and 32% of aortic, 8.3% and 10% of carotid, 11.8% and 14.7% of peripheral vascular, 9. 0% and 13.1% of intraabdominal/intrathoracic, 2.9% and 3.3% of intermediate -risk (head and neck and major orthopedic procedures), and 0.27% and 1.1% o f low-risk procedures respectively. The five associated patient-specific ri sk factors identified by logistic regression are: myocardial infarction <6 months (odds ratio [OR], 4.5; 95% confidence interval [CI], 1.9 to 12.9), e mergency surgery (OR, 2.6; 95% CI, 1.2 to 5.6), myocardial infarction >6 mo nths (OR, 2.2; 95% CI, 1.4 to 3.5), heart failure ever (OR, 1.9; 95% Cl, 1. 2 to 3.0), and rhythm other than sinus (OR, 1.7; 95% CI, 0.9 to 3.2). Inclu sion of the planned operative procedure significantly improves the predicti ve ability of our risk model. CONCLUSIONS: Five patient-specific risk factors are associated with high ri sk for cardiac complications in the perioperative period of noncardiac surg ery in veterans. Inclusion of the operative procedure significantly improve s the predictive ability of the risk model. Overall cardiac complication ra tes (pretest probabilities) are established for these patients. A simple no mogram is presented for calculation of post-test probabilities by incorpora ting the operative procedure.