Douglas et al in their article in NEJM compared the outcomes of anatomical
versus functional tests in patients with coronary artery disease.
They randomly assigned 10,003
symptomatic patients to an initial anatomical testing with the use of coronary
computed tomographic angiography (CTA) or to functional testing (exercise
electrocardiography, nuclear stress testing, or stress echocardiography). The
composite primary end point was death, myocardial infarction, hospitalization
for unstable angina, or major procedural complication. Secondary end points
included invasive cardiac catheterization that did not show obstructive CAD and
radiation exposure.
The mean age of the patients was
60.8±8.3 years, 52.7% were women, and 87.7% had chest pain or dyspnea on
exertion. The mean pretest likelihood of obstructive CAD was 53.3±21.4%. Over a
median follow-up period of 25 months, a primary end-point event occurred in 164
of 4996 patients in the CTA group (3.3%) and in 151 of 5007 (3.0%) in the
functional-testing group. CTA was associated with fewer catheterizations
showing no obstructive CAD than was functional testing (3.4% vs. 4.3%, P=0.02),
although more patients in the CTA group underwent catheterization within 90
days after randomization (12.2% vs. 8.1%). The median cumulative radiation
exposure per patient was lower in the CTA group than in the functional-testing
group (10.0 mSv vs. 11.3 mSv), but 32.6% of the patients in the
functional-testing group had no exposure, so the overall exposure was higher in
the CTA group (mean, 12.0 mSv vs. 10.1 mSv; P<0.001).
In symptomatic patients with suspected CAD who required noninvasive
testing, a strategy of initial CTA, as compared with functional testing, did
not improve clinical outcomes over a median follow-up of 2 years suggesting
that patients with chest pain have no less risk of heart attack, dying or being
hospitalized than those who take a simple stress test.
