Study supports more selective echo usage in AMI patients

Though it’s guideline-directed to assess acute MI (AMI) patients with echocardiography following a heart attack, hospitals that follow that rule incur greater costs and lengths of stay than those that employ echo more selectively, a recent study found.

Quinn R. Pack, MD, MSc, and colleagues wrote in JAMA Internal Medicine June 17 that while echocardiography is considered a key prognostic tool for AMI patients—clinical guidelines recommend all victims undergo echo to assess left ventricular ejection fraction (LVEF) and cardiac structure—it does little to improve patient outcomes. The team studied data from 397 hospitals in the U.S., using ICD-9 codes to identify 98,999 hospital admissions for AMI between January and December of 2014.

The authors launched their project in response to a paucity of data linking risk-standardized hospital rates of transthoracic echocardiography and patient outcomes. They said echos can inform treatment decisions for a range of conditions, including cardiogenic shock, coexisting valve disease, pericardial effusion and left ventricular thrombus, but just 32% of echo exams are associated with an active change in management and more than 20% of echocardiography reports are never even acknowledged in a patient’s medical record.

A little over 70% of AMI admissions logged in the Premier Healthcare Informatics inpatient database in 2014—69,652 admissions—included at least one transthoracic echocardiogram, the authors said. The average hospital risk-standardized rate of echocardiography in that pool was 72.5%.

Pack et al. found no difference in inpatient mortality or three-month readmission between the highest and lowest quartiles of echo use (median risk-standardized echo use rates of 83% vs. 54%, respectively), even when adjusting for hospital and patient characteristics. At hospitals with the highest rates of echocardiography use, however, patients stayed an average of 0.23 days longer and hospitals incurred an average $3,164 more per admission compared with centers in the lowest quartile of echo use.

“Rates of echocardiography in the setting of AMI vary between hospitals; however, higher rates were not associated with better clinical outcomes but were associated with higher costs and longer length of stay,” the authors wrote. “Although echocardiography plays an important role in the treatment of many patients with AMI, these findings suggest that a more selective approach may be safe and may reduce costs, particularly at high-use hospitals.”

The researchers said that since individual echocardiograms cost “considerably less” than $3,100, the stark difference in costs between high- and low-use hospitals is likely attributable to more than just a difference in echo usage. Hospitals with higher rates of echo use also had higher rates of nuclear testing and invasive ventriculography, potentially reflecting a hospital culture that encourages more testing and resource usage.

While Pack and his colleagues found no difference between echo rates and AMI patient outcomes, they said it was important to note their results don’t necessarily mean echocardiography is useless for AMI patients. Echos can direct the use of angiotensin-converting enzyme inhibitors and angiotensin receptor blockers in heart attack patients, as well as determine their eligibility for defibrillator use. 

“To be clear, our findings should not be interpreted to mean that echocardiography provides no value in AMI,” the authors wrote. “However, our overall results suggest that, at the margins, there may be clinical circumstances in which an echocardiogram can be safely deferred.”