Early Cardiac CTA Improves Decision-Making in Suspected ACS

CHICAGO, IL—Incorporating cardiac computed tomographic angiography (CTA) early in the evaluation of patients presenting to emergency departments (EDs) with chest pain can improve triage and clinical decision making compared with standard evaluation, according to results presented March 27, 2012, at the annual American College of Cardiology/i2 Scientific Session.

For the ROMICAT II (Rule-Out Myocardial Ischemia/Infarction using Computer Assisted Tomography) study, Udo Hoffmann, MD, of Massachusetts General Hospital and Harvard Medical School (Boston, MA), and colleagues evaluated 1,000 patients presenting to EDs with chest pain suggestive of acute cardiac syndromes (ACS) between April 2010 and January 2012.

The study is a follow-up to ROMICAT, which was published in the American Journal of Medicine in June 2009. Using a cardiac CTA evaluation strategy, the study found that only 8% of patients had ACS and most had no coronary artery disease (CAD) or non-obstructive plaque. According to Dr. Hoffmann, ROMICAT II was undertaken because data suggest that approximately 2% of patients are discharged from EDs with missed ACS.

Shorter Length of Stay, Similar Safety with Cardiac CTA

In ROMICAT II, patients were randomized to 1 of 2 strategies:

• Cardiac CTA, in which imaging was mandated as the first diagnostic test performed and was initiated as early as possible
• Standard evaluation, in which all care and management (stress testing, perfusion imaging, observation alone, etc), was at the discretion of local physicians

None of the sites routinely performed cardiac CTA as part of urgent care evaluation prior to the trial.

Length of hospital stay, the primary endpoint, was significantly lower in the cardiac CTA group compared with the standard evaluation group. The difference was driven primarily by a shortened length of stay in patients who did not have ACS as a final diagnosis. For the secondary safety endpoints, there were no missed cases of ACS in either study arm, 2 cases of peri-procedural complications (perioperative bleeding and increase in creatinine) in the cardiac CTA arm and similar MACE rates (a composite of death, MI, unstable angina and urgent revascularization) at 28-day follow up (table 1).

Table 1. Primary and Secondary Endpoints

 

Cardiac CTA advantages also carried over to discharge times with 50% of patients being discharged by the 8-hour mark, which was about 18 hours earlier than in the standard evaluation arm, Dr. Hoffmann said. By 12 hours, 3 times as many patients in the cardiac CTA arm had been discharged compared with those undergoing standard evaluation.

In addition, about 4 times as many patients were directly discharged home in the cardiac CTA arm compared with the standard evaluation arm, while about twice as many in the standard evaluation arm than in the cardiac CTA arm required admission for observation. Time to diagnosis was shortened by about 8 hours in the cardiac CTA arm, which was true for both ACS and non-ACS patients. There also were fewer repeat ED visits in the cardiac CTA arm at 28 days but no difference in repeat hospital admissions (table 2).

Table 2. Secondary Effectiveness Endpoints

 

Overall, testing during the index hospitalization was higher in patients receiving cardiac CTA compared with the standard evaluation arm (P < 0.0001), with 22% of patients in the latter group undergoing no tests, compared with 1.8% in the cardiac CTA group. Patients in the cardiac CTA arm also underwent more angiography (12% vs. 8%; P = 0.04) and more cumulative interventions (6.4% vs. 4.2%; P = 0.16).

Cumulative radiation exposure, a tertiary endpoint, also was higher in the cardiac CTA arm (14.3 ± 10.9 mSv vs. 5.3 ± 9.6 mSv; P < 0.0001), which was not surprising given the mandate for cardiac CTA in that arm.

ED costs were 19% lower for the cardiac CTA group compared with the standard evaluation group ($2,053 ± $1,076 vs. $2,532 ± $1,346; P < 0.0001), while total hospital costs were similar.

Significant Evidence Being Garnered

Dr. Hoffmann acknowledged that the study lacks statistical power to determine differences in health outcomes.

Panelist Matthew J. Budoff, MD, of Harbor-UCLA Medical Center (Torrance, CA), said the study adds to data from 2 previous trials (CT STAT and ACRIN PA).

“We’re now garnering significant clinical evidence with three randomized trials that all are very consistent,” Dr. Budoff said. But he also asked why they had chosen sites with no prior experience in cardiac CTA.

Dr. Hoffmann responded that since few EDs were using cardiac CTA at the start of their study, they felt there was “a common starting point” for the majority of centers in ROMICAT.

Concern About Radiation Exposure

One concern that was raised by panel co-chair Elliot M. Antman, MD, of Harvard Medical School (Boston, MA), was the cumulative radiation exposure.

“If one were to adopt this strategy, I think it is important to recognize that patients with chest pain symptoms often re-present to emergency departments that may not be the same hospital where they [first] present,” Dr. Antman said. Therefore, there is the potential for patients to have repeated exposures to procedural radiation.

But Dr. Hoffmann said cumulative radiation exposures for cardiac CTA scans are as low as 1 to 3 mSv, making them still a better overall choice considering that additional testing via a standard evaluation route carries the potential for far higher and more numerous exposures.

Study Details

Patients had 5 or more minutes of chest pain or equivalent within 24 hours prior to presentation and had a mean age of 54 ± 8 years. They were required to be able to hold their breath for at least 10 seconds and to be in sinus rhythm.

 

 

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Sources:1. Hoffmann U. A multicenter randomized comparative effectiveness trial of cardiac CTA vs. standard evaluation in acute chest pain patients in the emergency department: Results from the ROMICAT II trial. Presented at: American College of Cardiology Annual Scientific Session; March 27, 2012; Chicago, IL.

 

2. Lehman SJ, Abbara S, Cury RC, et al. Significance of cardiac computed tomography incidental findings in acute chest pain. Am J Med. 2009;122:543-549.

 

 

 

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