Author + information
- Published online February 4, 2019.
- Tamryn K. Law, MD,
- Zachary Bouck, MPH,
- X. Cindy Yin, BASc,
- David Dudzinski, MD, JD,
- Paaladinesh Thavendiranathan, MD,
- Gillian C. Nesbitt, MD,
- Jeremy Edwards, MD,
- Kibar Yared, MD,
- Harry Rakowski, MD,
- Rory B. Weiner, MD,
- R. Sacha Bhatia, RS, MD∗ (, )
- for the EchoWISELY Investigators
- ↵∗Department of Echocardiography, Women’s College Hospital Institute for Health Systems Solutions and Virtual Care, 76 Grenville Street, 6th Floor, Toronto, Ontario M5S 1B2, Canada
The appropriate use criteria (AUC) is intended to facilitate rationale of cardiovascular imaging and aid quality improvement efforts (1,2). Despite emerging research regarding the role of AUC for transthoracic echocardiography (TTE) in clinical practice, little data exist regarding the associations among TTE appropriateness, echocardiographic findings, or clinical outcomes. In a substudy of the EchoWISELY (Will Inappropriate Scenarios for Echocardiography Lessen Significantly) trial (3,4), we aimed to determine the relationship among TTE appropriateness, echocardiographic findings, and clinical outcomes.
The EchoWISELY (3,4) trial is a multicentered, randomized controlled trial of an educational intervention to improve appropriate ordering of TTE. In this study, outpatient TTEs were categorized according to appropriateness (appropriate, maybe appropriate [mA], or rarely appropriate [rA]), and echocardiographic data from TTE reports from 6 Ontario hospitals were entered into a clinical registry. Through a unique patient identifier, these records were linked to large administrative claims databases held at the Institute for Clinical Evaluative Sciences. Patients without a valid identifier (including non-Ontario residents), those who died before the scheduled TTE, or those hospitalized on the same date of the TTE were excluded. Finally, if patients had multiple TTEs on the same date, only the first TTE was included.
Descriptive statistical analysis was used to compare the echocardiographic findings by appropriateness rating for all classifiable TTEs, using chi-square tests of independence or Fisher’s exact tests, when appropriate. Statistical significance was indicated by a 2-tailed p value of <0.05. Statistical analysis was conducted using SAS (version 9.4; SAS Institute, Cary, North Carolina).
Of the 14,697 classifiable TTEs that were part of the EchoWISELY study, 9,230 TTEs from 6 participating hospitals in Ontario were included in this study, and after excluding mA TTEs from the analyses, a total of 8,661 TTEs were included. Table 1 shows the echocardiographic findings by the appropriateness rating, by comparing appropriate TTE versus rA TTE.
After relevant exclusions, 7,621 patients were included in the final clinical outcomes analysis. Patients who had an appropriate TTE had a higher hospitalization rate at 30 days (5.6% vs. 2.5%; p < 0.001), and a higher composite of death and hospitalization at 30 days (5.7% vs. 2.5%; p < 0.001) than those who received a rA TTE. At 1 year, the mortality rate for patients who had an appropriate TTE was higher than those who had a rA TTE (4.1% vs. 2.3%; p = 0.007), together with a higher hospitalization rate (27.5% vs. 19.7%; p < 0.001) and a higher composite rate of death and hospitalization (28.2% vs. 20.3%; p < 0.001).
As Table 1 indicates, this study from a large clinical registry demonstrated that appropriate TTEs had a significantly higher proportion of echocardiographic abnormalities than rA TTEs. Importantly, patients who had an appropriate TTE had a higher rate of adverse outcomes compared with those who had an rA TTE.
One of the major uncertainties surrounding the development of AUC was whether appropriateness was related to higher rates of clinically important cardiac imaging findings, which we confirmed in this study. However, rA TTEs did have a significant proportion of clinically relevant findings. This reinforced the importance of the AUC nomenclature change from “inappropriate” to “rarely appropriate” (5) because rA studies might be warranted to provide valuable clinical information in certain clinical situations. Second, because most of the AUC indication ratings are based on expert panel consensus rather than data from prospective studies, further research is required to determine optimal TTE frequency and reassessment, as well as how these factors may affect clinical outcomes, particularly in subgroups of patients with chronic cardiovascular disease. This is particularly true for surveillance studies in patients with valvular or myocardial abnormalities, and may explain why rA TTEs in our study were more likely to show significant aortic stenosis.
To our knowledge, this was the first study to show a significant association between appropriateness and outcomes. Our findings that patients who had appropriate TTEs had higher rates of adverse outcomes was novel, and reinforced the clinical importance of AUC. Further research is required to better understand the relationship of appropriateness and outcomes, particularly across different patient subgroups.
Please note: Funding was provided by the Peter Munk Cardiac Centre (Toronto, Ontario, Canada), the Ontario Ministry of Health and Long-Term Care, and the Cardiac Care Network of Ontario. Dr. Bhatia is supported by a new investigator grant from the Heart and Stroke Foundation of Canada. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.
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