NEW YORK (Reuters Health) – Just 38% of patients with suspected cardiac disease are found to have obstructive coronary disease on elective cardiac catheterization, new research shows. This low diagnostic yield suggests that clinical assessments and noninvasive tests are not doing their job in selecting patients for cardiac catheterization.
“Guidelines recommend continued observation in the case of patients who are at very low risk, noninvasive stress testing to determine the need for cardiac catheterization in the case of patients at intermediate risk, and direct referral for catheterization in the case of patients at high risk,” lead author Dr. Manesh R. Patel and colleagues note.
But whether these recommendations help limit the number of patients without coronary disease who undergo cardiac catheterization was unclear, according to the report in The New England Journal of Medicine for March 11.
To investigate, Dr. Patel, from Duke University Medical Center, Durham, North Carolina, and colleagues analyzed national registry data on nearly 400,000 patients without known coronary disease who had elective cardiac catheterization at 663 hospitals in the U.S.
Obstructive coronary disease was defined as stenosis of at least 50% of the diameter of the left main coronary artery or stenosis of at least 70% of the diameter of a major epicardial vessel.
The median patient age was 61 years and 52.7% of patients were male. Twenty-six percent of subjects had diabetes and 69.6% had hypertension. Roughly 84% had noninvasive tests before cardiac catheterization.
Only 37.6% of patients had obstructive coronary disease at catheterization, the report indicates. Moreover, 39.2% of patients had no coronary disease (stenosis <20% in all vessels).
A positive noninvasive test result slightly increased the likelihood of finding obstructive disease: 41.0% vs. 35.0% (adjusted odds ratio, 1.28, p < 0.001).
In an editorial, Dr. David J. Brenner from Columbia University Medical Center in New York agrees with the authors that a better “gatekeeper” test is needed to select the best candidate for cardiac catheterization. “Ironically,” he notes, “there is evidence that, in many situations, a better gatekeeper test may be yet another radiographic imaging technique—namely, multidetector-row computed-tomographic angiography.”
N Engl J Med 2010;362:886-895,943-945.