Background: Diagnostic coronary angiography is often followed by coronary stenting. Therapy with aspirin and clopidogrel is currently the standard treatment for patients undergoing coronary stenting. Clopidogrel loading is usually given prior to the procedure. Some pretreated patients, however, are found to have triple-vessel disease (3VD) or left main disease (LMD) that requires referral for coronary artery bypass graft (CABG) surgery. Surgery in patients pretreated with clopidogrel may be complicated by excessive bleeding or delayed to avoid that risk. Hypothesis: A risk factor-based formula may predict the likelihood that patients referred for coronary angiography will have 3VD or LMD. Methods: Consecutive patients (n = 2,180) referred for coronary angiography constitute the training subset (n = 1,296) used to build the model, and the validation subset (n = 884) used to test the model. Logistic regression models selected five variables showing strong associations with the presence of 3VD or LMD: age, gender, diabetes, hypercholesterolemia, and prior myocardial infarction (MI). A formula based on these variables and on the training subset was constructed to calculate the probability of 3VD or LMD. Results: Applying this model to the validation subset predicted 3VD or LMD with 79% sensitivity, 53% specificity, 45% positive predictive value, and 83% negative predictive value. Conclusions: This simple formula based on five clinical variables is helpful in predicting the likelihood that patients, referred for coronary angiography, will have 3VD or LMD. Use of this formula can help decide in which patients clopidogrel loading prior to angiography should be avoided.
- Coronary artery bypass graft
- Coronary stenting