A systematic review on the use of ultrasound enhancing agents with transesophageal echocardiography to assess the left atrial appendage prior to cardioversion

Background Assessment of the left atrium and atrial appendage (LAA) for thrombus by transesophageal echocardiography (TEE) may be suboptimal due to difficult imaging windows and ultrasound artifacts. The present study analyzed the benefit of using ultrasound enhancing agents (UEAs) with TEE to improve diagnostic accuracy and image quality. Methods A systematic review of studies published through December 2020 was performed, and included investigations comparing the number of cases deemed indeterminate for visualization of LAA thrombi on TEE pre- versus post-UEAs prior to cardioversion for atrial fibrillation or flutter (AF). Study results were pooled where the number of indeterminate cases by conventional TEE were re-classified as thrombus present, indeterminate, or thrombus excluded following administration of UEAs. Results Three studies with a total of 399 patients were identified. Of these, 83 (26%) participants met the inclusion criteria. The mean age of the study population from the three studies was 66 ± 12 years, 29% were female, and prevalence of congestive heart failure or neurologic events was 22% and 5%, respectively. Use of UEAs with TEE re-classified 66% (55/83) of cases initially deemed to be indeterminate for LAA thrombus on conventional TEE. Thrombus was present in 13% (11/83) and excluded in 53% (44/83) of cases; 34% (28/83) of cases remained indeterminate on TEE post-UEAs. There were no complications reported with the administration of UEAs. Conclusion Adjunctive use of UEAs with TEE can facilitate the diagnosis or exclusion of LAA thrombus, and improve the procedural confidence and cost-efficiency of cardioversion for AF.