Ultrasound-Enhancing Agent Safely Enhances Left Ventricular Visualization by Transthoracic Echocardiography in Patients on ECMO Support.

OBJECTIVE: The authors investigated if the use of ultrasound-enhancing agents (UEA) can safely improve left ventricular (LV) image quality by transthoracic echocardiography (TTE) in patients on extracorporeal membrane oxygenation (ECMO). DESIGN AND SETTING: This study was performed in a tertiary cardiothoracic and ECMO center in London, United Kingdom. PARTICIPANTS: The authors included 18 prospectively identified consecutive patients requiring TEE supported on peripherally implanted ECMO. INTERVENTION AND MEASUREMENTS: TTE was performed before and after the UEA administration. The authors assessed the LV image quality using the biplane (apical-4-chamber and apical-2-chamber views) endocardial border definition index (1 = good, 2 = suboptimal, 3 = poor, and 4 = unavailable), as well as the feasibility of LV ejection fraction (LVEF) measurement. The authors also gathered sequential clinical information for the next 24 hours. MAIN RESULTS: The patients' median age was 47 years (35, 65), and 5 (28%) were women. The biplane endocardial border definition index improved from the suboptimal to the good range (2.167 [1.812, 3.042] v 1.500 [1.417, 1.792], p = 0.0004) after the use of UEA. The feasibility of LVEF tripled from 25% (n = 5) to 83% (n = 15) (p = 0.0008) with UEA use. The UEA did not set off the bubble alarm and did not impact clinical or ECMO parameters. CONCLUSION: The use of UEA significantly improved the quality of LV biplane images by transthoracic echocardiography, transforming them from suboptimal to good in patients supported with peripherally implanted ECMO. UEA use tripled the feasibility of measuring LVEF by TTE without affecting clinical and ECMO parameters.