Can severe aortic stenosis be identified by emergency physicians when interpreting a simplified two-view echocardiogram obtained by trained echocardiographers?

Abstract

Background: Aortic stenosis (AS) is a common valve problem that causes significant morbidity and mortality. The goal of this study was to determine whether an emergency physician (EP) could determine severe AS by reviewing only two B-mode echocardiographic views (parasternal long axis (PSLA) and parasternal short axis (PSSA)) obtained by trained echocardiographers.

Methods: A convenience sample of 60 patients with no AS, mild/moderate AS or severe AS was selected for health record and echocardiogram review. The echocardiograms were performed in an accredited echocardiography laboratory. An EP blinded to the cardiologist's final report reviewed the PSLA and PSSA views after the cases were randomly sorted. Severe AS was defined as no cusp movement seen by the EP reviewers. A second EP independently reviewed 25% of randomly selected patients for inter-rater reliability. Collected data included patient demographics, EP interpretation and details of each echo view (quality, the number of cusps visualized, presence of calcification) and compared to final cardiology reports. Analyses included descriptive statistics, test characteristics for severe AS and kappa for agreement.

Results: The mean age was 75.3 years (range 18 to 90) with 36.7% females. The cardiologist's diagnosis was as follows: 38.3% severe AS, 28.3% mild/moderate AS and 33.3% no AS. The PSSA view was poorer in quality compared with the PSLA (33.3% vs. 13.3%, p = 0.02), but the PSSA view was better than PSLA to visualize all three cusps (83.3% vs. 0%, p = 0.001). There was no difference in the presence of calcification between the mild/moderate and severe AS groups (94.1% vs. 100.0%, p = 0.46). The sensitivity and specificity for EP diagnosis of severe AS was 75.0% (95% CI 56.7% to 85.4%) and 92.5% (83.3% to 97.7%). The kappa for severe AS was 0.69 (0.41 to 0.85), and there was no significant difference between observers in the quality of the view, presence of aortic calcification and the number of cusps visible.

Conclusions: PSLA and PSSA views obtained by trained echocardiographers can be interpreted by an EP with appropriate training to identify severe AS with good specificity. Further larger prospective studies are required before widespread use by EPs.