Cardiac CTA reveals significant incidental disease beyond the heart

August 17, 2007

A study by University of Maryland researchers has found that CT angiography exams performed after coronary artery bypass surgery can help physicians identify unsuspected, clinically relevant cardiac and noncardiac conditions.

A study by University of Maryland researchers has found that CT angiography exams performed after coronary artery bypass surgery can help physicians identify unsuspected, clinically relevant cardiac and noncardiac conditions.

Imagers learned years ago that many patients undergoing electron beam CT of the heart also showed incidental cardiac and noncardiac disease warranting management. Tests like coronary artery calcium scoring without contrast media, for instance, now popular for use with multislice CT scanners, can show such findings.

Scant information exists, however, on unsuspected disease in patients with known ischemia or those enduring heart surgeries, according to senior investigator Dr. Charles S. White, chief of thoracic radiology at the University of Maryland's Medical Center in Baltimore. Many patients undergo cardiac CTA at his institution, including those followed up after coronary bypass surgery. How many of them would show unrelated but clinically significant conditions affecting their hearts and lungs? White's team set out to find out the answer.

"We wanted to know the effect of using intravenous contrast and thinner slices on the prevalence of these findings," he said.

White and colleagues retrospectively reviewed data from 259 patients who had coronary bypass grafts between October 2002 and March 2006. On average, all patients underwent contrast-enhanced 16-slice CTA scanning about five days after surgery. The investigators found that almost 20% of these patients had at least one unsuspected but potentially dangerous cardiac or noncardiac condition. They published their findings in the August issue of the American Journal of Roentgenology.

Physicians detected ventricular pseudoaneurysms, perfusion deficit, or intracardiac thrombi in 24 patients (9.3%). Thirty-four patients (13.1%) showed noncardiac findings, such as pulmonary emboli, lung cancer, or pneumonia. Fifty-one (19.7%) showed at least one unrelated, potentially significant finding during the immediate postoperative period.

According to White, the number of patients found to have pulmonary embolism after a recent bypass graft was surprising. It is reasonable to suspect that cardiac surgery patients might have these problems, but the connection is not well known in the radiology community, he said.

"There was a fairly high rate of abnormalities that are found incidentally outside the coronary arteries and bypass grafts. The take-home message is that these examinations require physician interpreters who are trained to read the entire CT, not just the coronary vessels," he said.

For more information from the Diagnostic Imaging archives:

Dual-source CT excels in segment-by-segment diagnosis of coronary artery disease

JAMA study raises public awareness of radiation risk from cardiac CT

Coronary CTA dose reduction techniques prove consistency

Cardiac CTA helps in pre- and post-operative setting