|Inferior vena cava filter|
| Inferior vein cava percolate – Gunther Tulip .|
|Other names||IVC filter|
An inferior vena cava filter is a medical device made of metal that is implanted by vascular surgeons or interventional radiologists into the subscript vein cava to prevent a dangerous pneumonic embolism ( PE ) or venous thromboembolism ( VTE ). [ 2 ] [ 3 ] The filter is designed to trap a rake clot and prevent its change of location to the lung where it would form a pneumonic embolism. [ 4 ] [ 3 ] Their effectiveness and safety profile is well established, and they may be used when anticoagulant treatment is not sufficient. [ 5 ] Results from the PREPIC study and early studies which have shown many long-run complications of IVC filters led to the introduction of retrievable IVC filters. [ 6 ] The foremost retrievable IVC filters were approved by FDA in 2003 and 2004. [ 7 ]
In 2012, the American College of Chest Physicians recommended IVC filters for those with contraindications to anticoagulation who either have acute PE or acute proximal ( above the stifle ) deep vein thrombosis ( DVT ). [ 8 ] [ 9 ]
history [edit ]
visualize showing an inferior vein cava filter in its military position The beginning IVC filter was created by Kazi Mobin-Uddin, MD who published his findings in 1969 in the New England Journal of Medicine. [ 10 ] [ 11 ] [ 12 ] [ 13 ] The Mobin-Uddin percolate was late replaced by the Greenfield trickle developed by Lazar Greenfield which had a lower pace of trickle related complications. [ 12 ]
aesculapian uses [edit ]
Inferior vein cava filter as seen on plain X beam of the abdomen While the ability to retrieve a percolate does exist for many models, it can not be guaranteed that all cases of filter placement will allow for, or be indicated for retrieval. frankincense, the requirements and indications for permanent wave placement of filters is used to decide on when to use both permanent and irregular IVC filters. [ 14 ] long-run risk factors must be considered equally well, to include life anticipation of more than six months following insertion, and the ability of the patient to comply with anticoagulation therapy. [ 5 ] The decision to use a filter that is irregular volt permanent wave basically is tied to the expected duration of prison term that security is needed to prevent pneumonic embolus from passing to the heart and lungs. One such guideline is outlined below : [ 14 ]
- Contraindications to anticoagulation; e.g. a patient with DVT or PE who has another condition that puts them at risk of bleeding, such as a recent bleed into the brain, or a patient about to undergo major surgery
- Short-term risk of PE/Short-term contraindication of anticoagulation: Usually merits a retrievable filter
- Uncertain risk of PE and/or lack of control for anticoagulation: Usually results in permanent filters for long term management
- Long-term risk of PE/recurrent PE/recurrent DVT: permanent filter
indication categories [edit ]
While many studies have been done on the efficacy of Vena Cava filters, there still have not been any major studies done on the actual placement and removal of the filters regarding standard guidelines. Which is why the society of Interventional Radiology created a multidisciplinary panel that developed the following guidelines to see if person qualifies for implantation : [ citation needed ]
absolute indications [edit ]
These are patients that should strongly consider having IVC percolate placement, as they are at greatest risk of pneumonic embolus .
- Proven VTE: Venous thromboembolism and contraindication or complication due to anticoagulation therapy
- Recurrent VTE: Despite adequate anticoagulation therapy
relative indications [edit ]
This is a possibly category ; normally it represents patients who could benefit from an IVC percolate, but may be just fine without one arsenic well. [ citation needed ]
- Proven VTE: High risk of contraindication or complication to arise during anticoagulation therapy
- Large, free-floating proximal DVT’s
- Poor Compliance: INR levels are not stable, not taking medicine as directed
- Thrombolysis: Iliocaval DVT’s, which are emboli in the Illiac region
cautionary indications [edit ]
These are normally very controversial reasons to do an IVC filter, and most radiologists and doctors broadly will not recommend an IVC filter if other options are available rather .
- No VTE: Anticoagulation therapy is not possible (high risk of bleeding)
- Transient risk of VTE: Trauma, surgical procedures or medical conditions
other indications [edit ]
- Bariatric patients: Undergoing surgery for weight control, only if BMI greater than 55, previous history of DVT/PE, hypercoagulable state, chronic venous insufficiency, truncal obesity or contraindication to anticoagulation therapy.
Indications for removing IVC filter [edit ]
There is no current published datum confirming the benefit of removing an IVC. Because of this, the Society of Interventional Radiology created a multidisciplinary panel that developed the following guidelines to see if person qualifies for removal : [ 5 ]
- No need for permanent filter: Remove temporary
- Low risk of significant PE: Continued anticoagulation is working, remove temporary
- No expected near-term high-risk PE: Continuation of anticoagulation therapy, remove temporary
- Life expectancy of more than six months: Remove temporary
- Ability to retrieve the filter: No complications, no tear probability, no trauma probability; if so, remove temporary
anticoagulation [edit ]
In those with initial acute accent proximal DVT or acuate PE who had IVC filters placed alternatively of anticoagulation, and who have their risk of bleeding decide, the American College of Chest Physicians suggested, in 2012, that they receive a standard course of anticoagulation. [ 8 ] [ 9 ] While IVC filters are associated with a long condition risk of DVT, [ 16 ] [ needs update ] they are not, entirely, reason enough to maintain extend anticoagulation. [ 8 ] [ 9 ]
side effects [edit ]
The main function of a vein cava trickle is to prevent death from massive pneumonic embolus. long-run clinical follow-up studies have shown that this is accomplished in 96 % of cases having a standard stainless-steel Greenfield percolate. [ 17 ]
Abdominal radiogram shows that one of the leg ( arrows ) of the IVC percolate is pointed away from the expected IVC lumen.
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axial CT picture confirms that one of the branch ( arrow ) of the IVC filter has migrated out of the IVC wall into an adjacent tissue .
FDA communication [edit ]
In August, 2010, the FDA released an initial communication on the risk and adverse events associated with Long Term use of an subscript vein cava percolate. [ 18 ] Over a menstruation of about 5 years, they identify 921 events. While not the majority of cases, that number however represents a statistical significance of the consumption of long-run IVCs. Of these IVC filter side effects, 328 involved device migration, 146 involved embolizations after separation of device components, 70 involve perforation of the IVC, and 56 involved trickle fracture. much of the medical community believes that this large count of adverse events is related to the heart percolate remaining in place for longer than necessary. park issues relating to failure, to include death ( the early 4 % of cases ) include :
- Device-associated morbidity
- Device migration
- Filter embolization
- Filter fracture
- Insertion-site thrombosis
- Perforation of the vena cava
- Recurrent DVT
- Recurrent PE
- Thrombotic complications
- Vena cava thrombosis
Less common adverse reactions [edit ]
While these side effects are not common ( less than 10-20 % of patients ), many do report issues stemming from the placement and complication of the IVC while inside of the body. [ 19 ]
- 9% (12 of 132 patients) delayed filter penetration of the IVC greater than 3 mm
- Parts of filter broke off in 2% (5 of 230 patients)
- Caval filter migrated to heart or pulmonary artery (4 patients)
Numerous belittled published articles and character studies report describe similar issues to the above. Most notably :
- Filter fracture: Broken struts migrate to retroperitoneum, requiring exploration. Also struts can migrate to the heart and can cause pericardial effusion and tamponade.
- Perforation into the duodenum: Resulting in severe diarrhea and weight loss.
- Arterial hemorrhage: Requires surgery to avoid death.
- Misplaced Filter: Causes pericardiac tamponade requiring surgery under cardiopulmonary bypass.
- Filter Migration to Right Atrium: Resulting in acute myocardial infarction.
- Filter Lodged in Heart: Causes life-threatening arrhythmia and often requires pacemakers to resolve condition.
- Heart Migration: Requires surgery to remove IVC from heart.
- Sudden Death: Caused by the filter migrating to an active region in the heart.
- Migration of Filter to Chest: Requires surgery.
- Perforation of filter strut into small-bowel: Requires surgery to repair perforation.
evening though the cases above are the exception, and not the rule, most radiologists object to doing condom percolate insertions in patients who do not have thromboembolic diseases. [ 31 ] For the most separate, whenever possible, interventional radiologists would rather start the patient on anticoagulants than use an IVC, even if requested or referred via a repair. [ 32 ]
magnetic resonance imaging [edit ]
While most IVC filters are made of non-ferromagnetic materials, there are a few types that are weakly ferromagnetic. consequently, IVC filters fall under the MRI Safe and MRI Conditional categories depending by and large on type of fabric used during structure. rarely will one find an MRI not Safe IVC filter, as most of the steel, and early ferromagnetic material devices have been discontinued via the FDA. [ citation needed ] IVC filters are attached to the vein cava via hooks on their ends. Some are compression springs, which compress outward onto the side wall of the vein cava ; however, they hush have little hooks that retain their location. These hooks help in the anchor and healing procedure, as they allow the tissues to ‘ingrow ‘ around them, securing the IVC in place. It is improbable, then, after 4 to 6 weeks of mend, that an MRI of 1.5 tesla, up to 3 tesla, will cause any level of dislodging to occur to the IVC percolate. [ citation needed ] Studies of MR examination of both animals and humans, with plant IVC filters, have not reported complications or diagnostic filter supplanting. [ 33 ] [ 34 ] [ 35 ] [ 36 ] [ 37 ] [ 38 ] several animal studies have even used “ real-time ” MR for the placement of IVC filters to check for rotation, sheer, and other artifacts. [ 39 ] [ 40 ] As separate of the ‘routing ‘ review for MRI studies, patients who have IVC filters will frequently need confirmation from the doctor, or aesculapian records, to submit that the IVC is safe for the MRI. Most patients with weakly or non-safe ferromagnetic implants will be given a card, which they keep on their person at all time, that can help isolate if it is condom to do an MRI. For patients who have been denied MRI scans for safety reasons, doctors normally recommend the CT read with line as an option .
Labeling and recommendations [edit ]
Most IVC filters that have been tested have been labeled as “ MRi safe ” ; the remainder of IVC filters that have been tested are “ MR conditional. ” Patients who have been treated with nonferromagnetic IVC filters can undergo MR examination any fourth dimension after filter implantation. In patients who have been treated with a decrepit ferromagnetic IVC percolate ( Gianturco bird nest IVC trickle [ Cook ], stainless steel steel Greenfield vein cava filter [ Boston Scientific ] ), it is advised that the affected role delay at least six weeks before undergoing an MR examen ( because these older devices initially may not be anchored as firm in rate as early devices discussed in the give context ), unless there is a impregnable clinical indication to perform the MR examen sooner after implantation, and a long as there is no reason to suspect that the device is not positioned properly or that it is not firm in place. Most studies of IVC filters have by and large been conducted at 1.5 tesla or less, although many IVC filters have now been evaluated at 3 tesla and deemed acceptable for MR examen. [ 41 ] [ 42 ]
placement [edit ]
IVC filters are placed endovascularly, meaning that they are inserted via the blood vessels. Historically, IVC filters were placed surgically, but with advanced filters that can be compressed into much thin catheters, entree to the venous organization can be obtained via the femoral vein ( the bombastic vein in the breakwater ), the inner jugular vein ( the large vein in the neck ) or the sleeve veins with one blueprint. Choice of route depends chiefly on the number and location of any lineage curdle within the venous organization. To place the filter, a catheter is guided into the IVC using fluoroscopic guidance, then the filter is pushed through the catheter and deployed into the desire location, normally fair below the articulation of the IVC and the lowest nephritic vein. [ 43 ] review of prior cross-sectional visualize or a venogram of the IVC is performed before deploying the percolate to assess for potential anatomic variations, thrombus within the IVC, or areas of stenoses, american samoa well as to estimate the diameter of the IVC. rarely, ultrasound-guided placement is preferred in the set of contrast allergy, chronic kidney disease, and when patient stationariness is desired. The size of the IVC may affect which trickle is deployed, as some ( such as the Birds Nest ) are approved to accommodate larger cavae. There are situations where the filter is placed above the nephritic veins ( e.g. meaning patients or women of childbearing age, nephritic or gonadal vein thromboses, and so forth ). besides, if there is duplication of the IVC, the filter is placed above the confluence of the two IVCs [ 44 ] or a percolate can be placed within each IVC. [ 45 ]
retrieval [edit ]
The concept of a removable IVC filter was first conceived in 1967. [ 46 ] In 2003 and 2004 that the United States Food and Drug Administration beginning approved retrieavable filters. [ 47 ] In 2005 that the Society of Interventional Radiology ( SIR ) convened a multidisciplinary conference to address the clinical application of nonpermanent vein cava filters. [ citation needed ] retrievable filters are fitted with a device ( varying from model to model ) that allows them to be well snared and pulled back into a catheter and removed from the body, often through the jugular vein. Prior to 2004, filters that had been in the IVC for less than three weeks were considered desirable to attempt recovery, as filters that have been in stead long might have been overgrown by cells from the IVC wall and there was an increased risk of IVC wound if the trickle is dislodged. Newer designs, and developments in techniques mean that some filters can now be left in for drawn-out periods and retrievals after a year are now being reported. [ 48 ] This would include the ALN, Bard G2 and G2x, Option, Tulip and Celect filters. [ citation needed ]
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It is important to note that the clinical examination prior to the removal of the filter is full of life in understanding both the risk and pathophysiological effects removing the percolate will have on the patient. Doctors and checkup professionals must consider several key factors ( see Indications for removing IVC filters ). [ citation needed ]