64-slice CTA upheld as dependable test for ruling out CAD

Sixty-four-slice coronary CT angiography (CTA) is a reliable alternative to conventional coronary angiography for excluding coronary artery disease (CAD) in patients with diverse clinical presentations, according to Dutch researchers.

"We wanted to know if 64-slice CTA was comparable to invasive conventional coronary angiography in detecting significant coronary stenosis," explained Dr. Willem B. Meijboom in a presentation at the 2007 American College of Cardiology (ACC) meeting in New Orleans.

"We found that this modality has a high sensitivity to detect such lesions," added Meijboom, who is from Erasmus Medical Center in Rotterdam, Netherlands.

In this study involving 300 consecutive patients, the investigators compared 64-slice CTA (Sensation 64, Siemens Medical Solutions, Erlangen, Germany) with conventional angiography. Patients (average age 59) presented with atypical chest pain, stable or unstable angina, and non-ST-segment elevation myocardial infarction. All were scheduled for conventional angiography. Patients who had previously undergone coronary artery bypass graft surgery, as well as those who had had any percutaneous coronary interventions, were excluded.

Two observers read the CTA scans and were unaware of the results of conventional coronary angiography, which served as the reference standard for their statistical analysis. They defined significant stenosis as coronary lesions with at least a 50% luminal narrowing.

According to the results, 64% of the subjects had a significant lesion. The average CT scan time was 12.9 seconds, and the average heart rate was 58.9 beats per minute. The average calcium score was 437. In a segment-by-segment analysis, the 64-slice CTA exam had a sensitivity of 91% for detecting stenosis, and a specificity of 93%. The positive predictive value was 58% and the negative predictive value was 93%.

The most common complications for 64-slice CTA were contrast extravasation (two patients), second-degree atrial-ventricular block due to beta-blockers (one patient), and allergy to the contrast medium (two patients).

The low rate of complications and its high sensitivity make 64-slice CTA a viable alternative to conventional coronary angiography, Meijboom said.

By Paula Moyer
AuntMinnie.com contributing writer
April 30, 2007

Related Reading

Dual-source coronary CTA images the calcium-burdened, April 13, 2007

64-slice cardiac CT points to important incidental findings, March 19, 2007

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