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The use of coronary computed tomography ( CT ) angiography in the emergency room can successfully triage at-risk chest-pain patients and can do so faster and less expensively than standard diagnostic testing, the results of a new study.

"I think the reassurance is that both strategies are very safe," said lead investigator Dr James Goldstein (William Beaumont Hospital, Royal Oak, MI). "We've chosen a chosen a low-risk population—we don't want anybody to go home with a heart attack. We already know that the standard of care is a very fine strategy, and we've gotten very good at evaluating chest pain, but it is cumbersome and expensive."

Although the use of CT to rule out coronary artery disease should not be used in all patients, especially those with manifest ischemia, electrocardiogram abnormalities, or elevations in enzymatic biomarkers, among low-risk patients, "wisely and prudently applied," CT angiography is a powerful addition to the armamentarium of clinicians, said Goldstein.

The results of the study, known as the Computed Tomographic Angiography for the Systematic Triage of Acute Chest Pain Patients to Treatment (CT-STAT) trial, were presented at the American Heart Association 2009 Scientific Sessions.

Missed MIs a concern for ER doctors

During a morning press conference, Dr Kavitha Chinnaiyan (William Beaumont Hospital), a co-principal investigator, said that more than six million visits to the emergency department for chest pain occur in the US each year. Although estimates vary, she said that MI is missed in 4% to 13% of patients, and of these patients, mortality rates range from 10% to 25%. These missed MIs result in "huge litigation dollars," said Chinnaiyan, and account for 20% of all emergency-department malpractice dollars spent.

In CT-STAT, investigators included 750 patients with chest pain in the past 12 hours who presented to the emergency department and who had normal ECG and cardiac enzymes. These patients were randomized to a standard diagnostic workup or to the CT-angiography arm. Among the CT-treated patients, those with severe stenosis, >70%, were taken immediately to the catheterization lab for invasive angiography, while those with intermediate stenosis or uninterpretable CT images were sent for a nuclear stress test. An abnormal stress test resulted in invasive angiography, while patients with a normal result were sent home.

In the CT-angiography arm, there was no significant stenosis detected in 82.3% of patients, leading to an immediate discharge of 190 of 262 patients. At least one significant stenosis (>50%) was detected in 7.5% of CT patients, and moderate stenosis (25% to 50%) was detected in 9% of patients. Among those undergoing conventional care, myocardial perfusion imaging was normal in 90% of patients. Both CT angiography and conventional care led to similar number of patients referred for invasive coronary angiography, 6.9% and 6.2%, respectively.

Regarding the primary outcome, the time to diagnosis and hospital costs were significantly reduced with CT angiography. CT patients were discharged in approximately three hours compared with seven hours for those who received standard care. The costs were reduced 38% among those treated with CT, reduced from roughly $3500 with standard care to $2000 for CT angiography.

Source: Heartwire

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