As many as 25 percent of the 1.3 million cardiac catheterization performed each year in the United States may not be necessary, according to the recent study presented to the November meeting of the American Heart Associations Scientific Session in Orlando, Florida.
The study—called The Coronary Artery Evaluation Using 64-Row Multidetector Computed Tomography Angiography (CorE 64)—looked at 291 patients from nine US centers and seven foreign centers who subsequently underwent cardiac catheterization. The results were that the 64-Slice CT scanning is almost as accurate as cardiac catheterization in the diagnosis of cardiovascular disease.
Julie Miller, MD, the study’s first author, reported that the 64-slice CT was able to diagnose 91 percent of the lesions seen at cath and exclude 83 percent of the patients without any blockages. This was compared to the older 16-slice CT that could only show 20-30 percent of lesions. The newer scans could visualize 98 percent of the vessels 1.5 mm and larger. The study showed that 64-slice CT had a 85 percent sensitivity and 90 percent specificity in diagnosing lesions that blocked more than 50 percent of the vascular lumen, lesions that might need follow up cardiac catheterization and possibly surgical revascularization.
The new scanners were also quicker than the old scanners, making it possible to consider using it as an alternative to exercise stress testing in the elderly. And since there is no physiologic stress to the patient, there is no need to wait until a patient stabilized to undergo the diagnostic test. Such testing could prove routine to emergency physicians attempting to rule out cardiac causes of chest pain. There are currently about 5,000 64-slice CT scanners world-wide.
At the American Heart Association meeting, Orlando Regional Medical Center’s Dr. David Bello said that “the scans can reliably and quickly weed out nonheart patients from the 5.6 million who flood” the nation’s EDs “annually with chest discomfort.” He added, “The vast majority of people coming to the emergency department with chest pain do not need to spend two days in the hospital.”