August 7, 2009 – Using 64-slice CT coronary angiography can avoid further invasive angiographies, which can add up to significant cost savings, according to a new study in the American Journal of Cardiology (August 2009, vol. 104, issue 4, pages 498-500).
Researchers from the Baylor University Medical Center, Jack and Jane Hamilton Heart and Vascular Hospital, Dallas, Texas, said in a real world, clinical setting the negative predictive value of low-risk CTA is very high and exceptionally helpful in predicting freedom from events for up to three years. They said 64-slice CT coronary angiography is being used more often in the evaluation of patients with chest pain and the strength of this test is its high specificity and negative predictive value in exclusion of coronary artery disease (CAD).
However, they say its use remains controversial because there are theoretical risks of radiation, additional costs of the test, and no long-term data to suggest that excluding CAD by use of this test results in positive patient outcomes. A total of 436 patients underwent 64-slice CTA because of chest pain thought to be anginal. Cardiac CT was ordered by the primary physician or cardiologist based on a low to intermediate pretest probability of flow-limiting CAD. A smaller subset of patients initially underwent stress testing but had equivocal findings or continued symptoms that warranted further evaluation.
Of the total patient cohort, 376 had no significant CAD based on CTA results. Of the 60 patients who were believed on CTA to have flow-limiting CAD, 34 (57 percent) ended up having percutaneous coronary intervention or coronary artery bypass grafting. The remaining 26 patients (43 percent) did not have true flow-limiting disease on coronary catheterization and were treated medically. With follow-up of 36 months, all patients with minimal or no disease by CTA were free of events or intervention.
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