Elective cardiac cath found to have low diagnostic yield

Cardiac catheterization revealed obstructive coronary artery disease (CAD) in less than 40% of patients without previously diagnosed CAD who underwent the procedure, a new analysis found.

Using registry data from 663 U.S. hospitals, the study assessed almost 400,000 patients who underwent elective cardiac catheterization between 2004 and 2008. Of those patients, 37.6% had obstructive coronary disease, defined as stenosis of 50% or more of the left main coronary artery or 70% or more of a major epicardial vessel. Noninvasive testing had already been performed in 83.9% of the patients, but the study found that a positive result on a noninvasive test was only moderately predictive of obstructive disease, compared to patients who weren't tested.

The study did confirm the predictive value of some traditional risk factors for coronary artery disease. Male sex (odds ratio, 2.70; 95% CI, 2.64 to 2.76), older age (odds ratio per 5 years, 1.29; CI, 1.28 to 1.30), insulin-dependent diabetes (odds ratio, 2.14; CI, 2.07 to 2.21), and dyslipidemia (odds ratio, 1.62; CI, 1.57 to 1.67) were all independent predictors of obstructive disease. The study was published in the March 11 New England Journal of Medicine.

Based on the results, study authors called for improvement of current decision-making strategies for the use of invasive angiography. Particular attention should be paid to the 30% of patients who had no symptoms, given that the primary benefit of catheterization is relief of symptoms, and therefore the benefit to these patients is uncertain, they said. Improvement strategies for patient selection for catheterization should include, but not be limited to, improvements to the quality of noninvasive testing, the authors concluded.