(P207) THE USE OF CARDIAC POINT OF CARE ULTRASOUND (POCUS) VERSUS INPATIENT TRANSTHORACIC ECHOCARDIOGRAM (TTE) IN A LARGE TERTIARY CARE CENTRE: A COMPARABILITY AND APPROPRIATENESS STUDY

Background: Transthoracic echocardiography (TTE) use rates have increased year-over-year for the past decade across Ontario. The American College of Cardiology released appropriate use criteria (AUC) in 2019 for TTE to guide optimal resource utilization. In parallel, there has been increasing use of cardiac point of care ultrasound (POCUS) in clinical care. However, the evidence-base addressing the intersection between AUC, cardiac POCUS, and TTEs is limited. Our objectives were to describe a cohort of patients having underwent cardiac POCUS and TTE, identify the proportion of appropriate TTEs, compare patient outcomes and determine whether POCUS can support TTE triaging to potentially reduce low-yield TTEs.

METHODS AND RESULTS: This was a retrospective cohort study of patients admitted to a large academic hospital from June 1st 2022 to December 31st 2023, who had a General Internal Medicine (GIM) cardiac POCUS consultation. Baseline clinical and echocardiographic characteristics were obtained from electronic medical records. Indications for and administrative information on POCUS and TTEs, appropriateness of TTEs based on AUC, and comparison of left ventricular ejection fraction (LVEF), right ventricular function and pericardial effusion between POCUS and TTEs were extracted. Two independent reviewers assessed the AUC. Additionally, admission information, length of stay and mortality data were collected.

Among 283 patients who underwent a cardiac POCUS consultation, 61% (n=172) had an inpatient TTE. Three quarters (n=220) were admitted to GIM and one third had a prior history of heart failure (n=86). Most indications for POCUS included cardiac function/heart failure (n=111; 39.2%) and dyspnea/hypoxia (n=102; 36%). Of inpatient TTE indications, 84% (n=145) were appropriate and 16% (n=27) were inappropriate or uncertain. Seventy percent of TTEs revealed clinically significant findings, however only 32% of these were new findings from prior TTE. POCUS comparability to TTE for estimation of LVEF, right ventricular function and pericardial effusion was 90.1%. The sensitivity and specificity for POCUS identification of severely reduced LVEF < 30% on TTE was 90.5% and 96.0%, respectively. The median length of stay for those who only had an inpatient POCUS versus inpatient POCUS and TTE was 6.0 and 12.0 days, respectively. In-hospital mortality was comparable for both groups and was 14.8% (n=42) overall.

Conclusion: In conclusion, most inpatient TTE indications were appropriate, and GIM cardiac POCUS yielded similar results to TTEs for pre-specified findings of LVEF, RV function, and pericardial effusion. Analyses are ongoing to identify TTE indications that could be supplemented with cardiac POCUS, and potentially modify AUC for TTEs to optimize healthcare resources.