Is elective coronary angiography overused in patients with suspected coronary artery disease?

Evaluation of: Patel M, Peterson E, Dai D et al.: Low diagnostic yield of elective coronary angiography. N. Engl. J. Med. 362, 886-895 (2010). Guidelines for triaging patients for cardiac catheterization recommend risk assessment and noninvasive testing. The article by Patel et al. analyzes 398,978 patients and shows that only 37.6% had obstructive coronary artery disease at catheterization. No coronary artery stenosis (defined as <20% stenosis in all vessels) was reported in 39.2% of the patients. Independent predictors of obstructive coronary artery disease included male sex (odds ratio [OR]: 2.70; 95% CI: 2.64-2.76), older age (OR: 1.29; 95% CI: 1.28-1.30), presence of diabetes (OR: 2.14; 95% CI: 2.07-2.21) and dyslipidemia (OR: 1.62; 95% CI: 1.57-1.67). Patients with a positive result on a noninvasive test were moderately more likely to have obstructive coronary artery disease than those who did not undergo any testing (41 vs 35%; p < 0.001; adjusted OR: 1.28; 95% CI: 1.19-1.37). However, an angiogram's results do not tell us whether it was appropriately ordered. As the noninvasive testing variable included a wide range of procedures, we cannot speculate from the data how many diagnostic angiographies could have been avoided.