Definite Device-Related Thrombus on Cardiac Computed Tomography as a Fabric-Related Thrombus Mimic on Transesophageal Echocardiography.

BACKGROUND

Left atrial appendage closure (LAAC) is an established stroke-prevention option for atrial fibrillation patients unsuitable for long-term oral anticoagulation (OAC), while device-related thrombus (DRT) remains a complication. Cardiac computed tomography (CT) and transesophageal echocardiography (TEE) are modalities for its detection.

CASE SUMMARY: A patient after LAAC using WATCHMAN-FLX (Boston Scientific) underwent routine cardiac CT, which demonstrated an irregular, hypoattenuated surface lesion fulfilling criteria for definite DRT. However, the mass had a somewhat atypical configuration. Additional TEE demonstrated bulging confined to the device fabric with no thrombus extending into the left atrium. OAC was not intensified, and the patient remained stable.

DISCUSSION: This case illustrates a pitfall of CT-based DRT diagnosis in WATCHMAN devices. An eccentric fabric elevation can mimic a protruding thrombus.

TAKE-HOME MESSAGE: In post-LAAC patients with atypical CT findings suggesting DRT, adjunctive TEE is helpful to clarify thrombus location and prevent unnecessary OAC.