Ingrid Hein

November 29, 2016

CHICAGO — Hospital admission is lower when patients with chest pain in the emergency department are assessed with stress echocardiography than when they are assessed with coronary CT angiography, results from a new study suggest (NCT01384448).

Stress echo is often overlooked in patients with acute chest pain, but "it's a really reasonable option," said principle investigator Jeffrey Levsky, MD, PhD, from the Montefiore Medical Center in the Bronx, New York.

Acute chest pain is one of the most common reasons for a visit to the emergency department in the United States, accounting for some 8 million visits each year, so the safe and efficient diagnosis of patients is important.

Stress echo, which involves both ultrasound imaging and treadmill exercise, shows how well the heart muscle is working to pump blood to the body and can detect a decrease in blood flow to the heart related to severe narrowing of the coronary arteries. It is a noninvasive test with no wires and no catheter to the heart; however, it requires physician monitoring.

In contrast, coronary CT angiography is a specialized CT scan that images blood vessels in the heart while the patient rests.

"The reason you can compare these two very different modalities is that either can be considered for the same job, even though they measure very different things," Dr Levsky explained. Stress echo looks at physiology, whereas CT looks at anatomy.

"They're very different, but in general, they're considered interchangeable," he added. In many institutions, which tool is used depends on what is available, the local culture, and what lab is open when the patient arrives.

"We wanted to know which is better and safer and which will send more people home," he explained.

Head-to-Head Comparison

Dr Levsky presented results from the head-to-head comparison of the two diagnostic tools here at the Radiological Society of North America (RSNA) 2016 Annual Meeting.

The findings go against "the common thought process in field right now," as the current trend is toward CT scans, he reported.

That trend became stronger after results were released from the multicenter ROMICAT II and ACRIN-PENN randomized trials, which showed that coronary CT angiography improves hospital efficiency. However, those trials did not directly compare early stress echo with early coronary CT angiography.

In their study, Dr Levsky and his colleagues identified 1958 patients presenting to the emergency department with chest pain. They excluded from their analysis patients at very low to intermediate risk for significant coronary disease, those unable to exercise, those with allergies or asthma, those with recent intravenous access or contrast, and those receiving clinical treatment.

The remaining cohort consisted of 400 patients — 199 assessed with stress echo and 201 assessed with coronary CT angiography.

Table 1. Outcomes With Stress Echo and CT Angiography

Outcome Stress Echo (n = 199) Coronary CT Angiography (n = 201) P Value
Rate of hospitalization 11% 19% .02639
Median time spent in the emergency department 4.7 hours 5.4 hours .002
Median length of hospitalization 34 hours 58 hours .0021

 

At 30 days, there were fewer major adverse cardiovascular events in the stress echo group than in the CT angiography group.

Table 2. Adverse Cardiovascular Events During 30-Day Follow-up

Major Cardiovascular Event Stress Echo (n = 199) Coronary CT Angiography (n = 201) Total (n = 400)
Nonfatal myocardial infarction 4 7 11
Nonfatal stroke 3 1 4
Nonfatal cardiac arrest 0 1 1
Death 0 1 1
All major adverse cardiovascular events 7 10 17

 

Although this single-center study was underpowered to detect differences in cardiovascular events and revascularization, the results are nonetheless significant, Dr Levsky said.

"If you can send 8% more people home with stress echocardiography and you are talking about millions of patients, that's significant," he pointed out.

Stress echo has proven to be a fast diagnostic tool that entails no exposure to ionizing radiation and should be considered a first-line option for diagnosing chest pain in the emergency department, he told Medscape Medical News.

Rethinking the Gold Standard

"For the radiologist, this is a sort of a confirmation that there are alternative techniques available that challenge CT-based strategies," said Fabian Bamberg, MD, from the University of Tübingen in Germany.

"CT is the gold standard in imaging. We need to determine if other imaging technologies are effective for offering high standards of patient care," he told Medscape Medical News.

The RSNA community has been focused on assessing image quality, but "we need to assess standards of patient care rather than just looking at beautiful images together," Dr Bamberg said.

Advances in CT technology will likely soon provide better diagnostic information on blood flow, which will match some of the benefits of physiologic tests like stress echo and coronary CT angiography. For example, "CT fractional flow reserve is big in the CT business right now," he reported.

This trial was funded by the American Heart Association. Dr Levsky and Dr Bamberg have disclosed no relevant financial relationships.

Radiological Society of North America (RSNA) 2016 Annual Meeting. Presented November 28, 2016.

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