Thrombus formation on transcatheter ASD occluder device in a patient with coagulation factor XII deficiency.

Transcatheter occlusion of cardiac defects has become an effective and less invasive alternative to open heart surgery. Thromboembolic complications are rare events, after both surgical and transcatheter closure of atrial septal defects [Galal et al.: Eur Heart J 15:1381-1384, 1994]. We report on a case of thrombus formation on the atrial septal defect occluder system (ASDOS) [Sievert et al.: Cathet Cardiovasc Diagn 36:232-240, 1995; Hausdorf et al.: Heart 75:83-88, 1996]. Two days after transcatheter occlusion, the patient suffered an acute stroke due to embolism despite anticoagulation with intravenous heparin. A coagulation disorder with reduced factor XII concentration was deduced as the likely cause. Repeated transesophageal echocardiographic (TEE) studies revealed an involution of the intracardial thrombus within weeks of subsequent anticoagulatory treatment. First off, this case shows that patients with factor XII deficiency are at risk for thromboembolism. Second, it again clarifies that even large amounts of intraartrial thrombotic material may not be seen by transthoracic echocardiography (TTE) and underscores the necessity of performing TEE. Screening patients for coagulation disorders (Quick's value (Q), partial thromboplastin time (PTT)) before they are selected for treatment with thrombogenic devices is indispensable. With regard to their personal history (earlier thromboembolism) and the result of this screening (e.g., prolongation of PTT), quantitative determination of coagulation factors is reasonable. If patients endangered by thromboembolic complications nevertheless undergo ASD occlusion procedures, anticoagulation monitoring requires exceptional attention. Furthermore, it is recommended that TEE should be carried out in these patients 2 days after treatment, since transthoracic echocardiography (TTE) might be unable to detect thrombus formation on the device.