Reed Miller

December 03, 2009

December 3, 2009 (Chicago, Illinois) — Age and gender may be "simple" criteria to help pick which patients with acute chest pain should undergo coronary computed tomography angiography (CCTA), a secondary analysis of the Rule Out Myocardial Infarction Using Computer Assisted Tomography (ROMICAT) trial suggests [1].

Dr Fabian Bamberg (Massachusetts General Hospital, Boston) presented an analysis of the clinical utility of CCTA here at the Radiological Society of North America (RSNA) 2009 Scientific Assembly. The analysis shows that men under 55 and women under 65 benefit more from CCTA testing than older patients, supporting what physicians may already suspect, Bamberg said. "If you have an 80-year-old woman, the cardiac CT is going to be very limited anyway in terms of image quality, because of calcium, etc. That's the point of the study.

"We know that the current workup of patients with acute chest pain is somewhat suboptimal--it's not very sensitive or very specific, and there are really substantial practice costs associated with it. We do know that coronary CT may improve the management just by noninvasively excluding the presence of significant CAD," Bamberg said. However, "CT is not a perfect test, as it is associated with radiation and contrast administration, and therefore there is a need to define the target population that will have the greatest diagnostic benefit. So, the specific aim of the study was to identify age and gender subpopulations of patients with acute chest pain in whom coronary CT would yield the highest diagnostic gain."

As previously reported by heartwire , the 368-patient ROMICAT study showed that CCTA can rule out CAD and ACS in 50% of patients with a low to intermediate risk of disease presenting to an emergency room with chest pain [2]. A substudy from ROMICAT showed that the average number of CT cross-section images containing plaque corresponds to the plaque's progression [3].

All the patients in the study had normal initial troponin and a nonischemic electrocardiogram. Each underwent a 64-slice CT angiogram before hospital admission and was followed for six months for major adverse cardiac events. However, neither the patients nor the doctors knew the CCTA results, so further treatment decisions were based on later troponin testing or the emergence of unstable angina pectoris during hospitalization.

Bamberg and colleagues analyzed the prevalence of ACS, coronary stenosis, and diagnostic accuracy of CCTA in predefined age- and gender-specific patient categories--male or female, under 45, 45 to 54, 55 to 64, or over 65--and whether the CCTA results moved the patient into a new risk stratum. The risk strata are: less than 1% (very low risk), 1% to 4% (low risk), 4% to 16% (intermediate risk), and over 16% (high risk).

Importantly, in younger patients, a positive CCTA test for ACS led to restratification from low to high risk or from low to very low risk for a negative CCTA. But a negative CCTA result did not lead to restratification in women over 65 or men over 55.

Overall, 8% of the patients in the study had significant (over 50%) CAD. Presence of at least one significant coronary stenosis shown by CT and the likelihood of ACS increased with age for both men and women (p<0.001). CCTA was 100% sensitive and over 87% specific in women under 65. CCTA was 100% sensitive in men under 45 and 80% sensitive in men 45 to 54. Specificity was over 88.2% in men under 55.

Bamberg's presentation won an RSNA trainee research prize as the best paper presented by a resident.

Bamberg disclosed having no conflicts of interest. One of the coauthors of the paper, Dr Udo Hoffman (Harvard Medical School, Boston, MA), disclosed research grants from Bayer AG and the Bracco Group and advisory board positions with Vital Images, Siemens AG, and Bayer AG.


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