Inpatient echocardiography is on the rise and, with it, questions about potential overutilization. A new study suggests that, on the contrary, during critical cardiovascular hospitalizations, echo may not get tapped enough.

In the February edition of the Journal of the American College of Cardiology, Alexander Papolos, MD, of UC-San Francisco, and colleagues describe how they arrived at this conclusion after conducting a comprehensive review of inpatient echo use as reported over a 10-year period (2001 to 2010) in the Nationwide Inpatient Sample (NIS).

This database afforded them a look into around 8 million annual hospitalizations, which they used to correlate 2010 all-cause inpatient mortality with echocardiography utilization.

Their key finding: Echo use was associated with decreased odds of hospital mortality among five of the top six admission diagnoses—acute myocardial infarction, cardiac dysrhythmia, acute cerebrovascular disease, congestive heart failure and sepsis— for which echo was most commonly reported in the 2010 NIS.

These five diagnoses account for around 3.7 million national hospitalizations annually, but, the authors found, in 2010 the NIS database reported echo use in only 8 percent of cases.

Noting that the absolute volume and incidence of echo use did indeed steadily increase between 2001 and 2011 (at average annual rates of 3.41 percent and 3.04 percent, respectively), Papolos et al. conclude that, because patient selection and appropriate echo use are key to cost efficiency, their study suggests echo “may be underused during critical cardiovascular hospitalizations, most notably in the treatment of acute myocardial infarction.”

The authors acknowledge a number of limitations in their study and advise approaching their findings with caution.

The low use of echo in the NIS database “may simply represent institutional underreporting” of ICD-9 procedure coding in the inpatient claim data, they point out, while the sample size of their single-center validation cohort (18,401 study-qualifying diagnoses of interest at Mount Sinai Medical Center) “was underpowered to demonstrate a significance association between echo and mortality; larger prospective studies are needed.”

In related JACC commentary, the Cleveland Clinic’s Christine Jellis, MD, PhD, and Brian Griffin, MD, applaud the contribution of the study while concurring with the call for more research.

The Papolos et al. paper “reminds us that underutilization of safe, effective technologies such as echocardiography may have a broad economic impact,” they write, “and that healthcare strategies that may limit their utilization should be subjected to clinical trials and the cleansing light of actual data.”

Jellis and Griffin also note that the evident relationship between inpatient echocardiography and better clinical outcomes does not necessarily show causality.

“Prospective studies are required to determine if these findings can be replicated more broadly,” they write, “and if outcomes can be directly influenced by consistently adhering to appropriateness criteria and guideline recommendations for performance of echocardiography.”