In regions of the U.S. where cardiologists perform high numbers of cardiac catheterizations to diagnose heart problems, patients may be receiving PCI more than they need or want, according to a study published in the December 16/23 issue of Circulation.
In the study, researchers analyzed the relationship between cardiac catheterizations and the two most common invasive cardiac treatments: PCI and coronary artery bypass graft (CABG) surgery. They found a very high correlation between cardiac catheterization rates and PCI rates; and noted a much weaker connection between cardiac catheterization and the number of CABGs.
"Several recent studies on managing heart disease have touted the benefits of treatment with medication and lifestyle changes—as opposed to invasive treatment,” said the study’s principal investigator F. Lee Lucas, PhD, from the Maine Medical Center Research Institute in Scarborough. “The results from our study reflect what might be a tendency for physicians to opt for treating invasively rather than conservatively if they see anything unusual during the diagnostic process.”
To obtain their findings, the researchers reviewed a 20 percent sample of Medicare part B claims nationwide and calculated the rates of testing and treatment by region of the country, adjusting for regional demographic differences.
They found that cardiac catheterization rates varied substantially across regions, ranging from 16 per 1,000 in some regions to 77 per 1,000 in others. And, they saw a strong correlation of cardiac catheterization rates to total treatments (R 2=0.84). However, they also discovered a much weaker correlation between the tests and CABG rates (R 2=0.41) with the suggestion of a threshold, beyond which further testing did not result in additional surgeries.
On the other hand, Lucas and colleagues found that the correlation between cardiac catheterization testing rates and PCI rates was very strong (R 2=0.78) and linear, meaning the more tests conducted, the greater the numbers of PCIs performed.
The Northeast region had some of the lowest cardiac catheterization rates in the country, according to the authors.
Lucas and her team said that this study “sheds light on the real challenges that now face the medical community in the management of heart disease—the need for developing clearer criteria for performing these procedures, which are not without risks and the importance of taking the individual patient's preferences into account.”
“What we need to ask ourselves is 'Should we be testing more people?' And, once tested, should we treat every lesion, even if the individual's symptoms and quality of life are not likely to be impacted?” Lucas stated.
The Foundation for Informed Medical Decision Making in Boston funded the study.