Pulmonary Emboli (PE) are responsible for more deaths annually than breast cancer, AIDS and motor vehicle accidents combined. Prevention of Pulmonary embolism represents an important aspect of care for the vascular practioner. Numerous filters are available for implantation to prevent pulmonary embolus. Available filter types are listed below
IVC filter brands
- B Braun Tempofilter IVC filter (retrievable)
- B Braun VenaTech LGM IVC filter (no longer sold)
- B Braun VenaTech LP IVC filter
- Bard G2 IVC (retrievable, unlimited indwell time)[2]
- Bard Recovery IVC filter (retrievable) (no longer sold)
- Bard Simon Nitinol IVC filter[3]
- Boston Greenfield IVC filter
- Cook Birds Nest IVC filter
- Cook Celect IVC filter (retrievable)
- Cook Gunther Tulip IVC filter (retrievable)
- Cook Gianturco-Roehm Bird's Nest IVC Filter (not retrievable)
- Cordis OptEase IVC filter (retrievable, 23 day indwell time)[4]
- Cordis TrapEase IVC filter
- Mobin-Uddin Umbrella IVC filter (no longer sold)
- ALN IVC filter (retrievable)
- Rex Medical Option IVC filter (retrievable) (in clinical trials)
Recent data has emerged that the Optease/TrapEase device from Cordis are associated with a higher incidence of vena caval thrombois. Singer et al in JVIR 2009 Jun;20(6):799-805 and Leask RL et al JVIR 2004 May;15(5):485-90 used different models to assess the TrapEase's function. Singer et al using a three dimensional computer model of the TrapEase filter, examined the hemodynamics of steady state flow in the unoccluded and parially occluded filter. The study concluded that the upstream trapping position of the TrapEase filter leads to a potentially thrombogenic region of stagnant and or recirculating flow with low shear stress. Furthermore, the authors stated "these findings are supported by clinical studies showing an increased incidence of occlusive and nonocclusive thrombi"
Leask et al summarized that "there is a tendency for clots to be trapped between the filter and the vessel wall in the inferior inlet region. A clot in this region will generate a large region of flow stagnation/recirculation that is considered to be prothrombotic. In addition, a significant amount of the filter wire will be embedded in this region, which may promote thrombosis."
I would be interested to hear the feedback of practicing clinicians. I suspect that there is a specturm of opinions depending upon the type of practice ie vascular surgeon, IR and the setting ie community, academic. An extensive caval thrombus patient is likely to require lysis and if the filter placement individual is not the person that performs thrombolysis or if the patient is transferred to another facility do to extensive caval thrombus, then the person who placed the filter might not be aware of this type of potentially delayed complication.
Elsewhere,recently companies like Cook Medical have introduced technical iterations on currently existing devices like the Celect and Tulip vena caval devices. The NavAlign delivery system, available for both the Cook Celect® and Günther Tulip™ filters, is designed to minimize trauma and streamline filter placement with features unavailable on any other existing deployment system. A hemostatic valve minimizes blood loss at the point of entry, while a multipurpose dilator has radiopaque sizing bands and flushing sideports that decrease fluoroscopy time and the amount of contrast medium required.
I suggest that the the OptEase and TrapEase have had market share because of the first entry advantage and the associated clinical ease of deployment, however with advances in technology ongoing re-evaluation of practice patterns are necessary to provide the best outcomes to our patients
View deployment of the Guenther Tulip from Cook Medical