Objective: Presentation of unsual thrombogenic complication during transdermal atrial septal defect (ASD) closure.

Methods: Patients’ data undergoing transdermal closure of ASD or patent foramen ovale (PFO) were reviewed, with emphasis on thrombus formation during such procedures imaged by transesophageal echocardiography (TEE)

Results: Two patients were identified with thrombi during transdermal ASD closure; a 13 year old status post surgical correction of common atrioventricular canal and a residual ASD, and a 28 year old with a PFO and history of strokes. In both, during catheterization and immediately after balloon sizing of their defects, TEE revealed a large echogenic structure in the left atrium associated with the guiding wire and perceived as a thrombus. Routine heparin anticoagulation and therapeutic clotting time (ACT) was documented before inflation of the sizing balloon. Both pts were immediately managed with anticoagulation and thrombolysis. Resolution of the thrombus was achieved in the first case in a few hours, with subsequent removal of the guiding wire and closure of his defect at a later date. In the other case despite thrombolytic efforts the thrombus increased in size and was surgically removed followed with simultaneous surgical closure of the ASD. No evidence of systemic embolization was identified in either pt after clot removal.

Conclusions: Thrombi during transdermal ASD closure are not rare, but are usually associated with the device’s surface. Thrombi formed on guiding-wires used during the procedure, are also an existing risk. TEE is extremely helpful in their imaging and in preventing systemic embolism with their prompt identification.