Abstract P151: Diagnostic Yield of Elective Cardiac Catheterization After an Abnormal Stress Test: A Quality Initiative Study

Background: Guidelines for triaging patients for cardiac catheterization recommend a risk assessment and noninvasive testing. We determined patterns of noninvasive testing and the diagnostic yield of catheterization among patients with suspected coronary artery disease in our outpatient clinical center at Michigan State University. Methods: We conducted a retrospective cohort study of 133 consecutive patients who underwent elective cardiac catheterization from July 2008 through August 2010. Demographic characteristics, risk factors, symptoms and the results of noninvasive testing were correlated with the presence of obstructive coronary artery disease, which was defined as 50% or more of coronary artery stenosis. Results: The median age was 62 years with 71% men. Risk factors included diabetes 39%; hypertension 77 %; prior CAD 44% and dyslipidemia 79 %. Angina/chest pain was present in 62 % and atrial fibrillation in 7%. Patients with prior CAD receiving percutaneous coronary intervention were 34 % (20/58) as compared to 27% (20/75) without prior CAD. Noninvasive testing was performed in 78 % (104/133) of the patients. Among patients undergoing heart catheterization 53% (71/133) had obstructive coronary artery disease. A total of 97 patients had an abnormal stress test and 52% (50/97) had obstructive CAD. Associations with obstructive coronary artery disease were: male sex (odds ratio [OR], 1.51; 95% confidence interval [CI], 0.71, 3.19), older age (OR per 5-year increment, 1.21; 95% CI, 1.03, 1.42), presence of diabetes (OR= 1.51; 95% CI, 0.75, 3.06), and presence of dyslipidemia (OR=1.42; 95% CI, 0.62 to 3.29). Conclusions: Patients with a positive result on a noninvasive test were more likely to have obstructive coronary artery disease than those who did not undergo any testing but this did not achieve significance (52% vs. 48%; P=.76). A larger patient group may be required to confirm this observation. However, improved strategies for risk stratification could help increase the diagnostic yield of cardiac catheterization in routine clinical practice.