Case report. Thrombus formation on left atrial appendage clip: surgical exclusion and anticoagulation do not obviate transesophageal echocardiography prior to cardioversion

BACKGROUND: The cornerstone treatment for atrial fibrillation (Afib) is based on the prevention of cardioembolism with the use oral anticoagulants, which inherently increase the risk of bleeding. An alternative for these patients corresponds to left atrial appendage (LAA) exclusion/closure techniques such as Atriclip. CASES SUMMARY: Patient 1: Seventy-two-year-old female who presented with decompensated heart failure, non ST elevation myocardial infarct, and paroxysmal Afib. She underwent coronary artery bypass graft, MAZE procedure, mitral valve repair, and Atriclip (40 mm). Recurrence of Afib postoperatively led to a precardioversion transesophageal echocardiogram (TEE) which demonstrated a LAA pouch thrombus. Patient 2: Sixty-seven-year-old male who underwent electively mitral and tricuspid valve repairs, MAZE procedure, and Atriclip (35 mm). He had recurrent atrial flutter/Afib postoperatively. He received apixaban in addition to rate control medications, and he was readmitted for precardioversion TEE which also demonstrated a LAA pouch thrombus. DISCUSSION: Atriclip is a stapler exclusion device via epicardial approach which has shown excellent exclusion rates in contemporary data. One of the pitfalls of this technique is the possibility of leaving a LAA remnant stump or pouch that is highly thrombogenic. The optimal timing for stopping anticoagulation and the need for precardioversion echocardiography remain uncertain.