Do we perform too many invasive heart tests?

Nearly 40 percent of patients who underwent cardiac catheterization to diagnose heart disease were found to have no narrowing of their arteries, according to a study in the New England Journal of Medicine. The study by researchers at Duke University,  University of California at San Francisco, and the University of Texas examined the records of 398,078 patients, treated at 663 hospitals from January 2004 through April 2008.

The study was aimed at determining whether noninvasive tests and risk assessments for heart disease were good at identifying patients who needed more invasive testing such as a cardiac catheterization. This involves inserting a catheter into the patient's blood vessels usually through a small incision in the groin. The catheter is threaded up to the patient's heart where ink can be injected to help doctors see blood flow (and any obstructions) through the heart using real-time x-rays.

The researchers found that no coronary artery disease was found in 39.2 percent of the patients. Serious narrowing was found in 37.6 percent of the patients included in the study.

The researchers concluded that "better strategies for risk stratification are needed to inform decisions and increase the diagnostic yield of cardiac catheterization in routine clinical practice."

An analysis of hospital bills from Philadelphia and its four suburban Pennsylvania counties found that in 2008, 4,303 patients underwent cardiac catheterizations during an elective hospitalization. Overall, 22,507 patients in the five county area underwent cardiac catheterizations in 2008.