Nearly two-thirds of patients without confirmed heart disease who received angiograms turned out to not have heart disease, Dr. Manesh Patel of Duke University and his colleagues reported online in the New England Journal of Medicine. Specifically, only about 38 percent of these patients who underwent the elective screening procedure had potentially dangerous blockages in their coronary arteries.
Patel said the recent findings relating to angiograms should cause doctors to "carefully re-evaluate our process for determining" which patients with no history of prior heart disease should be screened using the test.
"It is still a very important place for patients with acute [heart attack], unstable symptoms, and certainly for patients for whom we're concerned about artery blockages," Patel said. But he also said that doctors must rely on other less invasive, less expensive tests as well to determine whether they need this screening.
Such an approach is supported by current guidelines. However, the methods for determining how invasive tests are ordered "are far from perfect," said Dr. Cam Patterson of the University of North Carolina at Chapel Hill, who was not involved in the study.
Researchers looked at 398,978 patients seen at 663 hospitals between January 2004 and April 2008 and found that patients without diagnosed heart disease account for roughly 20 percent of the patients who get angiograms. The vast majority are seen for other conditions that included heart attack and heart failure.
But Patel said that even within the group with no heart disease diagnosis, the fact that only 38 percent had a blockage "was surprising to us."
Angiograms are not the only tests that may be overused. Magnetic Resonance Imaging, or MRIs, CT scans, colonoscopies, and even PSA tests used to detect prostate cancer are all effective tools for the right patients. But according to many experts at times, all of these tests are overused.
"All can be great if used appropriately based on an individual case, and not just as routine for anyone," said Rosemary Gibson, author of the book, "The Treatment Trap." "Overuse is when the harm exceeds the benefits."
Some doctors continue to recommend tests that may not be necessary for the patient in order to keep him or her at ease about their health, said Dr. Harlan Krumholz, associate professor of medicine at Yale University School of Medicine.
"There is pressure from patients, there's concerns about missing something important. There's concerns about litigation," he said. "It has all come together in a culture where we really feel the need to do more and more."
According to Gibson, the current payment system for health care may be another reason why some doctors are quick to recommend tests.
"The open-ended payment system that we have buys right into this overuse," she said .