Outcome with Retrievable Inferior Vena Cava Filters: Lost in Translation

Venous thromboembolism (VTE) has an incidence of approximately 100 individuals per 100,000 population each year in the United States. ¹ The most common presentation of VTE is deep venous thrombosis (DVT) or its more feared complication, pulmonary embolism (PE). Each year VTE is responsible for the deaths of at least 100,000 to 200,000 patients in the United States who have an otherwise good prognosis and whose deaths could likewise be preventable. ² Anticoagulation (AC) is the preferred treatment for VTE, however, in selective patient populations, the risk of bleeding from AC outweighs its benefit. For these patients, alternative methods of PE prevention have been developed. ^3,4 Vena cava filters were introduced in the 1960s as a mechanical means to prevent PE. ⁵ Since that time, the number of filters placed has grown steadily to over 40,000 annually in the United States alone. ⁶ Randomized trials have shown that in addition to heparin therapy, the use of permanent filters initially reduces the occurrence of symptomatic or asymptomatic PE without changes in either immediate or long-term mortality. ⁷ It is well known that permanent filters lose their initial benefit in preventing PE by increasing the morbidity of long-term recurrence of DVTs. ⁷ Given these safety concerns, retrievable filters were developed to take advantage of short-term PE prevention benefit without the long-term disadvantages of increasing DVTs in patients with temporary contraindications to anticoagulation. Retrievable filters maintain their position by hooks, radial pressure or barbs, and can either be removed after placement or remain in place permanently. Indications for filter retrieval are based on the clinical situation, and the success rate decreases as the time post placement increases. The maximum successful documented dwell time for some of the filters range from 48 days in the OptEase filter to 357 days for the Celect filter. ¹ In this issue of the Journal, Janjua et al report the results from their retrospective study of 144 patients with retrievable inferior vena cava (IVC) filters. The purpose of their study was to evaluate the incidence of complications after filter implantation and the rate and success of filter retrieval in a community teaching hospital. ⁸ Among the 144 patients in this study, 53% had VTE and contraindication to AC; 14.5% had recurrent VTE despite AC; 25.6% needed greater protection because of a large PE, extensive DVT, compromised pulmonary function or concurrent embolectomy/endarterectomy; and 6% had VTE associated with cancer or thrombophilia. IVC filter-related complications occurred in 8.3% of the patients, half of which after 3 months of insertion. Described complications included IVC thrombosis in 2.1%; new DVT in 4.2%; new DVT with PE in 0.7%; and filter migration in 1.3%. In addition, 6.3% developed post-thrombotic syndrome. In this patient cohort, IVC filter retrieval was attempted in only 10% of the patients (n = 14) and the procedure was successful in 10 of 14 patients (71%). Unsuccessful attempts were performed in 4 patients at months 3, 6, 8 and 9 after insertion. There are several issues raised with this manuscript. First, we agree with the authors that a 10% rate of attempted IVC filter retrieval is very low and may reflect a lack of protocols and guidelines for filter retrieval, inadequate patient follow up and suggest a clear selection bias as to the patients studied. There are other reasons why temporary filters could be left in place permanently including large trapped embolus or filter thrombosis and ongoing indication for a filter. Similar studies in the past have reported an intention to perform filter retrieval up to 93% and as low as 11%, with an average of 54% among all the studies.1 What may be more important is the group in which the filter was not retrieved and why. Previous studies have shown and increased recurrence of DVT up to 11.6% after 2 years in patients with IVC filters; ⁶ in this study, the mean follow-up was 11 ± 10 months and the combined IVC thrombosis and occurrence of new DVT was 6.3%, which may reflect an underestimation of the rate of filter-related complications in this short follow-up period. The possibility of using retrievable filters has increased their rate of implantation in patients to take advantage of the perceived initial PE prevention benefit and to avoid the long-term complications by retrieving the filter on time. However, the process of filter removal requires two important issues to be followed. First, there must be a determination of who is responsible for follow up with the patient to be sure the filter is retrieved, and second, the physicians who place filters need to really be involved and understand the implications of prolonged and unnecessary indwelling filters. We learn from this study that retrievable filters play an important role in our armamentarium for the treatment of VTE and we agree with the authors that formal guidelines should be implemented to improve our current data set and understand where and when to retrieve filters and potentially increase the rate of filter retrieval where appropriate. We can conclude by saying that until practice guidelines for retrievable filter use are available, these devices should be used with caution in all cases. Further, they should be retrieved as soon as the indication for its insertion is resolved to prevent potential failure and long-term complications.

References

1. Tschoe M, Kim HS, Brotman DJ, Streiff MB. Retrievable vena cava filters: A clinical review. J Hosp Med 2009;4:441–448. 2. Buller HR, Agnelli G, Hull RD, et al. Antithrombotic therapy for venous thromboembolic disease. The Seventh American College of Chest Physicians on antithrombotic and thrombolytic therapy. Chest 2004;126:401S–428S. 3. Hann CL, Streiff MB. The role of vena caval filters in the management of venous thromboembolism. Blood Reviews 2005;19:179–202. 4. Baglin TP, Streiff MB. Guidelines on use of vena cava filters. Br J Haematol 2006;134:590–595. 5. Mobin-Uddin K, Smit PE, Martinez LO, et al. A vena caval filter for the prevention of pulmonary embolus. Surg Forum 1967;18. 6. Stein PD, Kayali F, Olson RE. Twenty-one-year trends in the use of inferior vena cava filters. Arch Intern Med 2004;164:1541–1545. 7. Decousus H, Leizorowich A, Parent F, et al. A clinical trial of vena caval filters in the prevention of pulmonary embolism in patients with proximal deep-vein thrombosis. N Engl J Med 1998;338:409–415. 8. Janjua M, Younas F, Moinuddin I, et al. Outcome with retrievable inferior vena cava filters. J Invasive Cardiol 2010;22:235–239.

_______________________________________________________________________ From the Section of Interventional Cardiology and the Vascular Medicine Program, St. Elizabeth’s Medical Center, Boston, Massachusetts. The authors report no conflicts of interest regarding the content herein. Address for correspondence: Lawrence A. Garcia, MD, FACC, FAHA, Chief, Section Interventional Cardiology, Associate Director, Vascular Medicine Program, St. Elizabeth’s Medical Center, 736 Cambridge Street, Boston, MA 02135. E-mail: Lawrence.Garcia@caritaschristi.org