AJR: Adverse cardiac events rare one year after negative CTA

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Cardiac CT with Somatom Definition
Image source: Siemens Healthcare

Researchers who followed low- to moderate-risk chest pain patients for one year after a negative cardiac CT angiography (CTA) in the emergency department found no signs or symptoms of adverse cardiac events during follow-up surveys, according to a study published in the October edition of the American Journal of Roentgenology.

Emergency departments (EDs) are increasingly turning to cardiac CTA for the evaluation of patients presenting with low- to moderate-risk chest pain and releasing patients with negative initial cardiac enzymes, negative initial ECG and a cardiac CTA negative for significant coronary artery disease (CAD).

Compared with the traditional standard of care, the CTA model may be associated with shorter length of stay and reduced costs, explained the researchers, led by William P. Shuman, MD, from the department of radiology at the University of Washington School of Medicine in Seattle.

“For earlier discharge based, in part, on negative cardiac CTA results to be clinically efficacious, it must be a safe practice with few subsequent adverse cardiac events,” wrote Shuman. Previous studies established the safety of the CTA model at one-, three- and six-month follow-up and in low-risk chest pain patients. Shuman and colleagues aimed to further establish the safety of the early discharge model by following low- to moderate-risk patients for one year.

The researchers recruited 81 consecutive patients with low- to moderate-risk chest pain, defined as a thrombolysis in myocardial infarction (TIMI) risk score of 0 to 4, between August 2006 and May 2008. After researchers excluded eleven patients for various contraindications, the study group of 70 patients included 40 men and 30 women (average age 54 years).

A radiologist and cardiologist, each with five years experience reading cardiac CTA studies, independently reviewed all data, defining a study as negative via the absence of significant CAD, marked by less than 50 percent diameter stenosis, explained Shuman and colleagues. Negative studies were further divided into no disease, 1 to 29 percent stenosis, and 30 to 49 percent stenosis.

Of the 70-patient cohort, 40 represented the no disease group, 19 had plaque with 1 to 29 percent stenosis, and 11 presented with 30 to 49 percent stenosis.

The researchers contacted patients at three-, six- and 12-months post-procedure with a standard survey including questions about adverse cardiac events such as myocardial infarction, coronary artery stenting, bypass surgery or death and about repeat ED visits, cardiac testing or procedures, hospitalizations related to cardiac diagnoses, cardiac-related care, initiation or change in medications and perception of the cause of chest pain, explained Shuman. The research team also reviewed the EMR at each time point.

“No patient reported any sign, symptom, finding or subsequent diagnosis suggestive of an adverse cardiac event, nor was there any such suggestion in the EMR,” reported Shuman.

The researchers acknowledged that the study population was relatively small, and Shuman suggested that the study should be repeated in a larger multicenter trial.