The application of appropriate use criteria for transthoracic echocardiography in a cardiac intensive care unit.

Background: Appropriate use criteria (AUC) represent an important mechanism by which to promote the rational utilization of healthcare resources. No study to date has been conducted assessing the applicability of current AUC to transthoracic echocardiograms (TTEs) performed in a cardiac intensive care unit (CICU). We analyzed 2 years of consecutive TTEs performed in a CICU at a quaternary-care academic medical center, hypothesizing that current AUC may not adequately describe the role of TTE in a modern CICU.

Methods: Indications for TTEs were independently classified by two investigators in accordance with 2011 AUC. If investigators were unable to assign an AUC classification to a given study, it was deemed to be unclassifiable. Disagreements between investigators were resolved by consensus. Cases in which consensus could not be reached underwent definitive adjudication by a third investigator.

Results: Of the 826 TTEs, 619 TTEs were classified as appropriate (74.9%, CI 71.8%-77.9%), 12 as uncertain (1.5%, CI 0.75%-2.5%), 21 as rarely appropriate (2.5%, CI 1.6%-3.9%), and 174 were unable to be classified (21.1%, CI 18.3%-24.0%). The most common unclassifiable indication was "initial evaluation of cardiac structure or function after cardiac arrest of unknown etiology" (n = 101).

Conclusion: Current AUC for TTEs may not adequately address the complexity of clinical cases encountered in the CICU. In our study of 826 consecutive TTEs, 21.1% were unable to be classified, reflecting the difficulty in applying AUC to this unique clinical environment. Further studies are therefore needed to better delineate the appropriateness of TTEs performed in the CICU.