International Journal of Cardiology 64 (1998) 299–300
A large embolus trapped by an inferior vena cava filter: A case report supporting inferior vena cava filter insertion a, b a Hiroshi Tada *, Nobushige Hayashi , Isamu Miyamori a
The Third Department of Internal Medicine, Fukui Medical University, 23 Shimoaizuki, Matsuoka-Cho, Fukui 910 -1193, Japan b The Division of Radiology, Fukui Medical University, 23 Shimoaizuki, Matsuoka-Cho, Fukui 910 -1193, Japan Received 28 October 1997; received in revised form 25 December 1997; accepted 6 January 1998
Abstract We describe a patient with a deep vein thrombosis causing multiple pulmonary emboli. After inferior vena cava filter insertion, a large embolus was trapped by the filter. Anticoagulation following filter insertion decreased the pulmonary artery pressure, and there was no recurrence of pulmonary embolization. Thus, in the presence of large, multiple thrombi in the proximal veins, inferior vena cava filter had better be inserted before thrombolytic treatment to prevent a lethal pulmonary embolism, and anticoagulant therapy is important after filter insertion. 1998 Elsevier Science Ireland Ltd. Keywords: Inferior vena cava filter; Pulmonary embolism; Deep vein thrombosis
Deep vein thrombosis is a major cause of pulmonary embolism. Preventing pulmonary embolization by interrupting vena cava flow has been utilized since 1893. Both the short-term effectiveness and longterm safety of the use of the Greenfield vena cava filter for the interruption of vena cava flow have been confirmed [1,2]. We present which demonstrates the usefulness of inferior vena cava filters in the prevention of pulmonary embolism from a large thrombus. To our knowledge, trapping of a large thrombus by an inferior vena cava filter has not been previously reported.
1. Case report A 64-year-old Japanese man was admitted with a 1 year history of progressive shortness of breath. *Corresponding author. Tel.: 181 776 613111; fax: 181 776 618111.
Physical examination revealed a blood pressure 100 / 50 mmHg and a regular pulse at a rate of 84 / min. A right ventricular heave was palpable along the left parasternal borders and the intensity of the pulmonic component of the second sound was increased. Arterial blood gas analysis with the patient breathing room air demonstrated severe hypoxemia (PaO 2 48.4 mmHg) and hypocapnia (PaCO 2 30.4 mmHg). A ventilation-perfusion scan revealed multiple segmental defects. Selective pulmonary arteriography revealed multiple obstructions of the bilateral lobular arteries. The pulmonary artery pressure was 70 / 32 mmHg with a mean value of 45 mmHg. Digital subtraction venography of the left lower extremity revealed thrombi in the left common iliac vein (Fig. 1A). A Greenfield filter (Boston Scientific Co., Boston, MA) was placed in the inferior vena cava via the right femoral vein (Fig. 1B). Subsequent digital subtraction venography performed via the right
0167-5273 / 98 / $19.00 1998 Elsevier Science Ireland Ltd. All rights reserved. PII S0167-5273( 98 )00027-8
H. Tada et al. / International Journal of Cardiology 64 (1998) 299 – 300
Fig. 1. (A) Digital subtraction venography of the left lower extremity. Thrombi (arrows) are seen in the left common iliac vein (LCIV). (B) Greenfield vena cava filter placed in the inferior vena cava (IVC). (C) Subsequent digital subtraction venography via the right femoral vein. A large embolus (41 mm317 mm) is trapped by the filter in the inferior vena cava.
femoral vein revealed a large embolus (41 mm317 mm) trapped in the inferior vena cava by the filter (Fig. 1C). After treatment with urokinase, heparin, and antiplatelet agents, a third digital venogram was performed 10 days after filter insertion and showed resolution of the embolus. The pulmonary artery pressure had decreased to a mean pressure of 26 mmHg after therapy. No recurrent pulmonary embolisms occurred during the follow-up period of 2.5 years. The patient remained on warfarin therapy after filter placement and thrombolysis.
2. Discussion Anticoagulation remains the primary therapy for deep vein thrombosis and pulmonary embolism. However, this treatment fails to prevent thromboembolism in 10% of patients and is associated with a mortality rate of up to 15% . In addition, thrombus formation within the inferior vena cava is associated with an embolism rate of 35% despite full anticoagulation . Failure of anticoagulant therapy to prevent recurrent embolism is the second most common indication for filter insertion , suggesting that medical therapy alone may be inadequate in many patients. In particular, patients with chronic pulmonary hypertension have a high incidence of recurrent thromboembolism, and coumarin administration does
not improve survival . Therefore, anticoagulant therapy is not sufficient to prevent recurrent pulmonary embolism. Percutaneous insertion of intracaval devices has replaced the direct surgical interruption of vena cava flow. Caval patency rates exceed 95% with use of the Greenfield filter. Use of the Greenfield filter is associated with an overall recurrent pulmonary embolism rate of 4% over 12 years . In this patient, the inferior vena cava filter trapped a large embolus originating from the proximal veins. If thrombolytic treatment is carried out before placement of an inferior vena cava filter, serious pulmonary embolism may occur. Therefore, an inferior vena cava filter had better be inserted before thrombolytic treatment if large or multiple thrombi are present in the proximal veins. Concomitant anticoagulation after filter insertion is important for several reasons . First, anticoagulation prevents deep vein thrombosis at the site of filter insertion. Second, it prevents inferior vena cava thrombosis and prevents cephalad propagation of clot from an occluded filter. Third, it prevents propagation or recurrence of lower extremity deep vein thrombosis. In our patient, anticoagulation after filter insertion decreased the pulmonary artery pressure to a mean pressure of 26 mmHg, and the patient had no further pulmonary embolisms during the follow-up period. The present case demonstrates the importance of concomitant anticoagulant therapy in patients with a large clot burden.
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