Novel Use of the ACCUNET Embolic Protection System
During Mechanical Thombolysis of a Prosthetic Aortic Valve

Carotid angioplasty and stenting are emerging as new treatment options for patients with carotid stenosis that are considered high risk for surgical carotid endarterectomy. Neurologic deficits related to embolic debris are the main limitation to these procedures. A variety of cerebral protection devices have thus been developed and are currently undergoing clinical trials. We describe a novel use of the ACCUNET™ Embolic Protection System (Guidant, Indianapolis, Ind.) during mechanical thrombolysis of a thrombosed prosthetic aortic valve. Case Report. An 18-year-old male without prior cardiac disease was healthy until he developed altered mental status, elevated temperatures and shortness of breath. Transthoracic and subsequent transesophageal echocardiography confirmed endocarditis of the aortic valve, prolapse of the right and non-coronary cusps, an extensive aortic valve ring abscess and severe aortic insufficiency (Figure 1). Magnetic resonance imaging of the brain showed a ring enhancing focus within the right parietal area consistent with an abscess. Patch closure of the aortic valve ring abscess cavity and reconstruction of the right and non-coronary cusps was performed. The post-operative course was unremarkable and he was discharged home on hospital day-7. He was readmitted 6 weeks later for progressive shortness of breath. Echocardiography showed a recurrent aneurysm of the aortic root, dehiscence of the previous annular repair, mild dilation of the left ventricle and severe aortic regurgitation. Aortic valve replacement was performed using a CarboMedics S500 Top Hat Valve (23 mm) and the aneurysm was sutured closed. On the third post-operative day, transthoracic echocardiography showed a maximum transaortic gradient of 88 mmHg. Fluoroscopy confirmed a frozen valve leaflet. On the fourth post-operative day, high dose intravenous heparin was begun and continued for 4 days. Thrombolytic therapy was not administered because of recent surgery and the intracerebral abscess. Repeat transthoracic echocardiography continued to show a maximum transaortic gradient of approximately 80 mmHg. In an attempt to avoid re-operation, placement of bilateral embolic protection devices followed by mechanical thrombolysis of the aortic valve was planned. An emergency use device exemption for the ACCUNET Embolic Protection System was obtained from Guidant, an informed consent was obtained and our institutional review board and the FDA were appropriately informed. Six Fr sheaths were placed in the right and left femoral arteries and a 6 Fr sheath was placed in the right brachial artery. The ACCUNET devices were placed in the left and right internal carotid arteries (Figure 2). A 6 Fr pigtail catheter was positioned in the ascending aorta via the right brachial artery (Figure 3). The catheter was vigorously advanced against the aortic valve multiple times without achieving free movement of the frozen valve leaflet. This was repeated unsuccessfully with a 6 French multipurpose catheter. Transeptal puncture using a Brockenbrough needle and Mullin’s sheath was performed to approach the valve in an anterograde direction. A 6 Fr balloon tipped catheter was placed into the left ventricle via the Mullin’s sheath and forcefully advanced multiple times against the aortic valve. Flouroscopy subsequently showed normal movement of the previously frozen valve leaflet (Figure 4). Post-intervention transthoracic echocardiography showed a reduced maximum transaortic gradient of 34 mmHg. Inspection of the left filter basket showed embolic debris. The patient was discharged to home on hospital day 28 receiving coumadin and aspirin. One year following hospital discharge, he continues to do well. Summary. Treatment options for prosthetic valve thrombosis include heparin, thrombolysis and repeat surgical intervention.1-7 Thrombolysis is often contraindicated in the setting of recent cardiac surgery and surgical intervention is associated with significant mortality.8 Mechanical thrombolysis using percutaneously inserted catheters is therefore an attractive alternative to standard therapies, but poses a significant risk for embolism with left-sided cardiac valves. Because of an inadequate response to heparin, a contraindication to thrombolytic therapy and the desire to avoid repeat surgery in a young adult, we deployed bilateral embolic protection devices in the carotid arteries and performed successful mechanical thrombolysis. Inspection of the left filter basket following the procedure showed embolic debris, further confirming the benefit of the ACCUNET Embolic Protection Sytem filter in this case.

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