Using Workload to Predict Left Main Coronary Artery Stenosis in Candidates for Coronary Angiography

Background: Coronary angiography, albeit a safe procedure, may cause serious complications especially in patients with left main stenosis (LMS). This study was designed to investigate the ef_cacy of workload achieved by exercise tolerance test (ETT) in predicting LMS in candidates for coronary angiography. Methods: A total of 743 patients with a positive ETT who subsequently underwent cardiac catheterization were retrospectively studied. Different risk factors were compared among the patients with and without LMS. A multivariate forward stepwise logistic regression analysis was used to identify the main predictors of LMS. Results: Among our 743 patients, 72% were male and 41(5.5%) had LMS_50%. Patients with LMS, by comparison with those without LMS, were older and were more likely to be male and had higher percentages of ejection fraction less than 35% (EF_35%), history of myocardial infarction, and lower metabolic equivalent (METs). After adjusting for important variables, we found that EF_35%, METs, and the male sex were significant independent predictors of LMS (P < 0.0001, P=0.024, and P=0.006, respectively). When the patients were divided into two groups in terms of METs_7 and METs > 7, LMS was found in 8.3% and 3.6%, respectively (P=0.006). The risk of having LMS in the men with METs_7 was higher than that in those with METs > 7 (OR=3, P=0.003, 95% CI=1.50-6.00). Among the patients with LMS, stenosis_70% was found in 44% in METs_7 and 18.8% in METs > 7. Conclusion: Lower METs correlated with an increased likelihood of significant LMS in the patients, especially if they were male, who had a positive exercise test and were suspected of coronary artery disease. It is, therefore, advisable that patients with METs_7 receive due attention during coronary angiography.