Background: Preoperative clinical indexes to stratify cardiac risk have not been validated angiographically. Our aims were to determine the concordance of clinical risk with severity of coronary stenosis and to develop and validate a preoperative clinical index to exclude the presence of significant coronary stenosis.
Methods and results: We carried out a prospective study of 878 consecutive patients (including the derivation and validation sets). "Severe" stenosis was defined as three-vessel (> or = 50% stenosis in each), two-vessel (> or = 50% stenosis in one when the other is > or = 70% stenosis of the left anterior descending), or left main disease (> or = 50%); "critical" stenosis was three-vessel (> or = 70% stenosis in each) and/or left main stenosis > or = 70%. A preoperative clinical index (diabetes mellitus, prior myocardial infarction, angina, age > 70 years, congestive heart failure) was used to stratify patients. A gradient of risk for severe stenosis was seen with increasing numbers of clinical markers. The following prediction rules were developed: The absence of severe coronary stenoses can be predicted with a positive predictive value of 96% for patients who have no (1) history of diabetes, (2) prior angina, (3) previous myocardial infarction, or (4) history of congestive heart failure. The absence of critical coronary stenoses can be predicted with a positive predictive value of 94% for those who have no (1) prior angina, (2) previous myocardial infarction, or (3) history of congestive heart failure.
Conclusions: By reliably identifying a large proportion of patients with a low likelihood of significant stenoses, these prediction rules can help to substantially reduce healthcare costs associated with preoperative cardiac risk assessment for noncardiac surgery.