From the Division of Cardiology, Department of Medicine, University of Utah, Salt Lake City, Utah. The authors report no conflicts of interest regarding the content herein. Manuscript submitted April 2, 2009 and accepted May 4, 2009. Address for correspondence: Andrew D. Michaels, MD, MAS, Division of Cardiology, University of Utah, 30 North 1900 East, Room 4A100, Salt Lake City, UT 84132-2401. E-mail: firstname.lastname@example.org
_______________________________________________ ABSTRACT: A 77 year-old female was referred for percutaneous patent foramen ovale (PFO) closure after suffering a cryptogenic stroke. Transesophageal echocardiography demonstrated a PFO with atrial septal aneurysm and probable right atrial pacemaker lead thrombus immediately adjacent to the PFO. She underwent successful, uncomplicated PFO closure using intracardiac echocardiographic guidance, without dislodgement of extensive pacemaker thrombus. Pacemaker lead thrombus is common, and is an underrecognized source of thrombus in patients with cryptogenic stroke. Preprocedure transesophageal echocardiography is critically important prior to PFO closure in pacemaker patients, and should prompt weighing the risks of anticoagulation, percutaneous closure, and surgical closure.
J INVASIVE CARDIOL 2009;21:E224–E225
Case Presentation. A 77 year-old non-smoking female presenting with a cryptogenic stroke was found by transthoracic echocardiography to have a patent foramen ovale (PFO) with an atrial septal aneurysm. She had a history of pacemaker placement for sick sinus syndrome with a total of two right atrial and two right ventricular leads. Evaluation excluded atrial fibrillation, left ventricular dysfunction, significant carotid artery or aortic atherosclerosis, lower-extremity venous thrombosis, and a hypercoagulable state. Transesophageal echocardiography confirmed the presence of the PFO and also identified probable right atrial thrombus on a pacemaker lead. She was referred for percutaneous closure of her PFO. Two weeks after starting warfarin, she underwent PFO closure with intracardiac echocardiographic (ICE) guidance. ICE imaging clearly showed two areas of large mobile thrombus adherent to one or more of the four pacemaker leads coursing through her right atrium, very close to the PFO (Figure 1). Using extremely careful technique to avoid dislodgement of the right atrial pacemaker lead thrombus, the patient underwent successful PFO closure using an Amplatzer Cribriform 25 mm occluder (AGA Medical Corp., Plymouth, Minnesota) without complication (Figure 2). A repeat echocardiographic bubble study showed no residual interatrial shunting. The patient was continued on warfarin, and has had no recurrent neurologic events after 6 months of follow up. Discussion. This is the first report of a cryptogenic stroke in association with a pacemaker lead thrombus in a PFO patient. Imaging studies have shown that thrombus on pacemaker leads is fairly common. The incidence of thrombus on permanent transvenous pacemaker leads detected by TEE has ranged from 9–32%.1,2 Furthermore, paradoxical emboli may account for as many as 47,000 strokes in the United States annually.3 There is only one report of an infected pacemaker lead presenting with septic paradoxical embolus through a PFO.4 Right atrial lead pacemaker lead entrapment against the atrial septum by the right atrial disk has been reported during PFO closure.5 Performing TEE in pacemaker patients prior to PFO closure is a critically important preprocedure imaging test. If pacemaker thrombus is identified, the operator should strongly consider delaying PFO closure until the thrombus is resolved, or consider surgical PFO closure. Even though our patient had successful, uncomplicated PFO closure in the presence of extensive pacemaker thrombus, there is a definite risk of procedural stroke. On the other hand, there is also a risk of cryptogenic stroke while waiting for the thrombus to resolve with anticoagulation. Conclusion. Pacemaker lead thrombus may be an important and underrecognized source of thrombus in patients presenting with cryptogenic stroke. Echocardiographically-guided PFO closure (preferably with ICE) may be attempted in these patients after carefully weighing the risks of continued anticoagulation, percutaneous closure, and surgical closure. ICE may be superior to TEE for the imaging of pacemaker thrombus because of the close proximity of the ICE catheter in the right atrium. However, the risk of pacemaker thrombus dislodgement must be considered when performing ICE in these patients.