Use of ultrasound enhancing agents in transesophageal echocardiography to improve interpretive confidence of left atrial appendage thrombus

Background The value of ultrasound enhancing agents ( UEA ) in patients undergoing transesophageal echocardiography ( TEE ) for the exclusion of left atrial appendage ( LAA ) thrombi prior to direct current cardioversion ( DCCV ) is evolving. Methods We retrospectively identified 88 consecutive TEE s, where a commercial UEA was used during LAA interrogation. De‐identified non‐enhanced (pre‐ UEA ) and enhanced cine loop images (post‐ UEA ) from the same subjects were randomly reviewed by four expert readers in a blinded fashion. Results In 33% of the cases, UEA use was associated with a statistically insignificant improvement in physician confidence (scale, 0‐3) in determining the presence or absence of a LAA thrombus ( P  = 0.071). In instances where non‐enhanced images yielded an uncertain interpretation or when the left atrium contained spontaneous echo contrast ( SEC ), UEA use was associated with an improvement in interpretive confidence in 49% ( P  < 0.001) and 41% of the cases ( P  = 0.001), respectively. Overall, the absolute rate of hypothetical decision to proceed with DCCV rose by 9% with the application of UEA ( P  = 0.004). In instances where non‐enhanced images were interpreted with limited confidence or when SEC was present, there were absolute increases of 16% ( P  < 0.001) and 21% ( P  < 0.001) in hypothetical procession to DCCV , respectively. In cases of a combination of limited interpretive confidence and SEC , UEA use was associated with a 29% absolute increase in the rate of procession to DCCV ( P  < 0.001). Conclusions In patients undergoing TEE interrogation of the LAA , the use of UEA is associated with an increase in the level of interpretive confidence and higher rates of theoretical procession to DCCV .