Critical appraisal of cardiac risk stratification before elective vascular surgery

This study was undertaken to evaluate the efficacy of the cardiac risk stratification protocol proposed by the American College of Cardiology/American Heart Association (ACC/AHA) in predicting cardiac morbidity and mortality associated with elective, major arterial surgery. Cardiac risk stratification using ACC/AHA guidelines was done on 425 consecutive patients before 481 elective cerebrovascular (n = 146), aortic/inflow (n = 166), or infrainguinal (n = 169) procedures at an academic Veterans Affairs Medical Center. Cardiac risk was stratified as low, intermediate, or high based on clinical risk factors, such as, Eagle criteria, history of cardiac intervention, patient functional status, results of noninvasive cardiac stress testing, and coronary angiography with coronary revascularization performed when appropriate. Outcomes (myocardial infarction, unstable angina, congestive heart failure, ventricular arrhythmia, cardiac death, and mortality) within 30 days of surgery were compared between the various risk stratification groups. Univariate and multivariate analyses were used to identify clinically useful prognostic variables from the preoperative cardiac evaluation algorithm. Overall mortality (1.7%), cardiac death (0.4%), and adverse cardiac event (4.8%) rates were low, but cardiac death and morbidity were increased (p < 0.05) in high-risk stratified patients (3.4%, 11.9%) compared to intermediate (0%, 2.8%) and low (0%, 4.0%) cardiac risk groups. The presence of 3-vessel angiographic coronary artery occlusive disease was an independent predictor of cardiac morbidity, while inducible ischemia by cardiac stress imaging was not. Previous coronary revascularization was associated with increased mortality as was the development of a non-cardiac complication. Cardiac risk assessment identified 78 (18%) patients with indications for coronary angiography. Angiographic findings resulted in coronary artery intervention (9-angioplasty; 4-bypass grafting) in 13 (3%) patients who experienced no adverse cardiac events after the planned vascular surgery (15 procedures). Cardiac risk stratification using ACC/AHA guidelines can predict adverse cardiac events associated with elective vascular surgery; however, protocol modification by increased reliance on Eagle criteria and less use of cardiac stress testing can improve identification of the "highest risk" patients who may benefit from prophylactic coronary intervention.