From the *Borgess Heart Institute and Michigan State University/Kalamazoo Center for Medical Studies, Kalamazoo, Michigan, and Borgess Heart Institute, Kalamazoo, Michigan. The authors report no conflicts of interest regarding the content herein. Manuscript submitted July 13, 2009 and accepted August 10, 2009. Address for correspondence: Vishal Gupta, MD, MPH, Assistant Professor of Medicine, Michigan State University, Director, Medical Device Research Laboratory, Associate Director, Cardiovascular Research Institute, Associate Program Director Interventional Cardiology Fellowship, Borgess Medical Center, 1521 Gull Rd., Kalamazoo, MI 49048. E-mail: firstname.lastname@example.org
ABSTRACT: Pulmonary embolism is the third most common cardiovascular disease. For prevention of pulmonary embolism, vena caval filters are extensively used in the United States. Of the reported complications of vena caval filters, strut fracture of the filter is the least common. We present a rare case of pericardial tamponade from fractured filter strut/leg embolization. We also discuss a possible hypothesis for the filter fracture along with its complications.
J INVASIVE CARDIOL 2009;21:E221–E223
Key words: recovery filter, filter fracture, filter complication, pericardial tamponade, angiography, arrhythmia
Case Presentation. A 31-year-old Caucasian female presented to the emergency department with severe retrosternal chest pain which started 2 days prior to arrival. The pain was positional and worse with inspiration. There was associated nausea and diaphoresis. The pain began after rigorous physical activity 2 days prior to presentation. On examination, she was diaphoretic and tachycardic. Her jugular venous pressure was elevated; her heart sounds were muffled and she had pulsus paradoxus. Her electrocardiogram (ECG) showed diffuse ST-elevation and PR-segment depression consistent with acute pericarditis (Figure 1). Her past medical history included placement of an inferior vena-caval (IVC) Recovery® Filter (C.R. Bard, Tempe, Arizona) for a history of Factor V Leiden deficiency and pulmonary embolism after a motor vehicle accident 4 years prior to presentation. She was also on chronic anticoagulation with warfarin with an admission international normalized ratio (INR) of 2.9. An emergent transthoracic echocardiogram (TTE) (Figure 2) was performed and showed a large pericardial effusion as well as evidence of pericardial tamponade. The running diagnosis at the time of admission was hemorrhagic pericarditis leading to tamponade since she was on chronic anticoagulation, had classic symptoms, and an ECG suggestive of pericarditis prior to admission. She was administered vitamin K intravenously and started on fresh-frozen plasma (FFP) in anticipation of a pericardiocentesis to prevent further accumulation of pericardial fluid. While she was receiving the FFP, the patient deteriorated, becoming unresponsive and hypotensive. She was taken to the cardiac catheterization laboratory emergently and a pericardiocentesis was performed under fluoroscopic guidance. After draining 350 cc of bloody fluid from the pericardial space, she stabilized hemodynamically. After stabilization, the physician was hard-pressed to believe that the hemorrhagic pericarditis could cause such a precipitous tamponade and looked for possible alternative causes. After scrutiny of the fluoroscopic images, they noticed a faint, barely visible object “like a bent wire”, in the area of the pericardium. He undertook magnified cineangiography of the object (Figures 3a and b). Given the patient’s past history and present clinical condition, the keen observation and ability to relate the findings, the physician suspected this object to be a part of an IVC filter. Fluoroscopy of the abdomen was then performed to locate the IVC filter. A magnified view was obtained in order to count the legs of the filter and match this up with the known leg count (12 legs). This magnified view showed that one of the legs of the IVC filter was missing (Figure 4). It was hypothesized that the missing leg of the IVC filter had embolized to the right heart, perforating the wall and leading to pericardial tamponade. Numerous cineangiographic views, including right ventriculography, were obtained to locate the position of the filter leg in the pericardium. A computed tomographic (CT) scan of the chest was also performed to accurately identify the location of the filter leg and it was found to be in the epicardial fat with the sharp edge towards the right ventricular myocardium (Figure 5). Cardiothoracic service was consulted and they removed the filter leg (2.5 cm x 0.1 cm) by lower sternotomy. The patient did extremely well after the procedure and was discharged on postoperative day 5. Discussion. Pulmonary embolism (PE) is the third most common cause of death for cardiovascular disease after acute ischemic syndromes and stroke, accounting for 300,000 deaths annually.1 The incidence of PE in the United States exceeds 1 per 1,000, with a > 15% mortality rate in the first 3 months after diagnosis.2 For prevention of PE, anticoagulation remains the primary therapy, but IVC filters are indicated when anticoagulation is impossible or has failed. For prevention of PE, interruption of the IVC was first suggested by Trousseau in 1868 and was subsequently performed by Bottini in 1893.3,4 Vena-caval (VC) filters were first used in 1967. The Kimray-Greenfilter was the first modern device made of stainless steel. IVC filters can be permanent or temporary and retrievable. There are different VC filters available in the United States; the permanent filters include: the over-the-wire stainless steel alternating hook Greenfield (Boston Scientific Corp., Natick, Massachusetts) filter, the titanium Greenfield filter (Boston Scientific), the Bird’s Nest filter (Cook, Inc., Bloomington, Indiana), the Simon nitinol filter (Nitinol Medical Technologies Group, Woburn, Massachusetts), the Vena Tech LGM LP filters (B. Brown, Evanston, Illinois), the TrapEase filter (Cordis Corp., Miami Lakes, Florida) and the G2 recovery filter (C.R. Bard, Tempe, Arizona). The U.S. Food and Drug Administration approved four temporary/retrievable filters: The Gunther Tulip filter (Cook), the Bard Recovery filter (C.R. Bard), the OptEase® filter (Cordis) and the Celect™ filter (Cook). The Bard Recovery® filter is made of nitinol wire (0.013 inch) and has two parallel planes with six legs in each plane for better clot trapping. It is anchored to the IVC by the legs and can be removed by a special urethane-cone device. VC filters have many complications involving the procedure and the filter itself. Serious procedural complications such as pneumothorax, cerebrovascular accident and death are rare. Filter complications like IVC penetration by filter prongs, tilting, and migration are more common and usually asymptomatic. Other significant complications include erosion of the IVC, visceral perforation, IVC thrombosis, insertion-site thrombosis, recurrence of PE, retroperitoneal hematoma, and small-bowel obstruction. A few cases of migration of the whole filter to the heart and pulmonary arteries have been reported in the literature. Fracture of the filter strut/leg is a very rare complication and its consequence depends upon the site of embolization of the strut. This is the third such reported case,6,7 but only the second case leading to pericardial tamponade. In all of these cases, filter fracture may have occurred during excessive physical activity. Interestingly, all were Bard Recovery filters, including our case. The time gap between filter placement and fracture varied from months to years; in our case, 4 years had elapsed. It was hypothesized that the mechanism of fracture may be due to malapposition or continuous strain leading to metal fatigue. This can be validated by the fact that in all these cases fracture was associated with rigorous physical exercise. The unique aspect of this case is that filter fracture was not initially suggested and could have been overlooked if the interventionalist had not maintained a high level of suspicion. Most complications of the filters are benign, but one should be aware of potentially fatal ones like this. Early identification and prompt surgical removal can save lives. Acknowledgements. We would like to thank Mark Loehrke, MD, FACP, Hemasri Tokala, MD, Mihas Kodenchery, MD, Pradyumna Majumdar, MD, and Michael Khaghany, MD for their support and assistance in the preparation of this article.