Inferior Vena Cava Filters (IVCFs)

Inferior Vena Cava Filters(IVCFs) Katie Boniface| Melody Chan Carolyn Kwok | Caleb Ollech Duke University Pratt School of Engineering BME 525 – Biomedical Materials December 16, 2012 Start http://www.ivcfilterattorney.com/

Abstract Inferior Vena Cava Filters Deep vein thrombosis (DVT) and pulmonary embolism (PE) are common preventable causes of morbidity and mortality. Anticoagulation is the preferred method of treatment, however some patients have a contraindication to anticoagulation or are intolerant of therapy. For these patients, an inferior vena cava filter (IVCF) is an effective alternative treatment. An IVCF is a surgically implanted device intended to block the passage of pulmonary emboli to the heart and lungs. http://www.cambriasomersetradiology.com/interventional-radiology/ivc-filter This presentation is an educational tool intended to disseminate knowledge on the development and use of inferior vena cava filters. This presentation is strictly informational and should not in any case be used in place of a physician consultation. To Main Menu http://bloodjournal.hematologylibrary.org/content/95/12/3669.long

View Abstract Design & Fabrication Disease State (DVT & Pulmonary Embolism) Main Menu Implant Procedure IVCF Performance & Failure Doctors & Vendors Instructions References Review Quiz

Instructions Home Back button: Takes you back to the last slide viewed Reference Number: For full citations, click to go to the References Page Home button: Takes you to the main menu Instructions [A1] Navigation bar: Displays your location within the tutorial Instructions: Takes you to this page, the tutorial instructions << Back To Main Menu << Felix the Filter: Takes you to the tutorial’s site map for easy navigation through all of the tutorial’s sections. He will occasionally offer helpful advice on certain pages of the tutorial. If a hand ( ) appears when hovering over any portion of the presentation, click to “press” the button and find out more! This presentation is an educational tool intended to disseminate knowledge on the development and use of inferior vena cava filters. This presentation is strictly informational and should not in any case be used in place of a physician consultation.

Disease State Home Deep Vein Thrombosis & Pulmonary Embolism Disease State Risks & Symptoms What is it? Disease Progression Causes How does an IVC filter help?

Disease State What is it? Home Head & upper body Understanding deep vein thrombosis and pulmonary emboli requires knowing how blood flows through the body: Blood Flow & the Circulatory System: Blood flows through our circulatory system in a multi-branching circular pathway. After flowing through the lungs and transporting oxygen to the body’s tissues, our blood becomes oxygen-poor and returns to the heart via the superior or inferior vena cava. Superior vena cava What is it? [B1,B2] Lungs Inferior vena cava Lower body & internal organs Next http://www.humanbody.dke-explore.com/clipart/human/image_human056.htm

Disease State What is it? Home Deep vein thrombosisis a blood clot in an interior vein. A clot inside a blood vessel is known as a thrombosis. DVT formation typically begins inside the vein valves of the calves where blood is relatively oxygen-deprived, activating certain biochemical pathways that cause clotting to occur. What is it? [B1,B3] http://www.sirweb.org/patients/deep-vein-thrombosis/ Back to Disease State Menu

Disease State Risks & Symptoms Home Mouse over each question for more information! Risk Factors & Symptoms [B4,B5] How common is DVT? What are the risk factors for DVT? What are the symptoms of DVT? http://helifeofdebralewis.blogspot.com/2011/07/dvt-deep-vein-thrombosis-what-does-it.html Back to Disease State Menu

Disease State Causes of DVT & PE Home • Blood flow stasis Mouse over each piece of the triad to view definitions! There are three main causes of venous thrombosis, known as Virchow's triad: • Hypercoagulability Causes of DVT/Pulmonary Embolism [B1,B5,B6] • Endothelial injury Back to Disease State Menu

Disease State Home Disease Progression The most serious complication is a life-threatening pulmonary embolism, the result of a thrombosis detaching from (embolizing) and traveling to the lungs. DVT and pulmonary embolism are parts of the same disease process called venous thromboembolism. Superior vena cava Progression of DVT to Pulmonary Embolism [B1] Inferior vena cava Embolus Femoral vein Thrombus Saphenous vein Venous valve Popliteal vein Click to learn more about pulmonary emboli

Disease State Home Disease Progression Progression of DVT to Pulmonary Embolism [B1] If an embolus breaks off a clot in the lower body and travels to the lungs (pulmonary embolism), symptoms are more severe and frequently include: • Shortness of breath • Chest pain (similar to heart attack, worse with exertion) • Weak pulse • Cough (often with bloody sputum) • Lightheadedness/fainting Click to see how an embolus gets to the lungs

Disease State Home Disease Progression How does deep vein thrombosis (DVT) progress to pulmonary embolism (PE)? Progression of DVT to Pulmonary Embolism http://www.youtube.com/watch?v=zyNTlx5eWtk&feature=related Back to Disease State Menu Click here if video does not load

Disease State How does an IVC filter help? Home An inferior vena cava filter (IVCF) is a surgically implanted device intended to block the passage of pulmonary emboli to the heart and lungs. Click the button below to view an animation of how an IVCF prevents flow of pulmonary emboli. How does an IVC filter help? Screenshots taken from: http://vimeo.com/18934756 Click to learn about IVC filter indications

Disease State IVC Filter Indications Home Indications of IVC Filter Placement [A1] Causes of contraindication include… • Bleeding diathesis • Recent major surgery • Intracranial neoplasm • Hemorrhagic stroke Potential Indications To learn more about indications for IVC placement, click on the following: Unsubstantiated Indications

Disease State IVC Filter Indications Home Potential Indications [A1] Scroll over each indication for more information! Next

Disease State IVC Filter Indications Home These indications are “unsubstantiated” due to a lack of clinical data confirming the benefit of IVC filter placement. Unsubstantiated Indications [A1] Scroll over each indication for more information! Back to Main Menu

Home IVC Filter Design Click on the blue buttons to learn more! “The goal of filter placement is to try to obtain high quality filtering efficiency (large and small emboli) without impedance of blood flow and with reduced device-related thrombosis while minimizing migration and without penetration of the vessel wall.” – U.S. Food and Drug Administration IVC Filter Design Materials Selection Filter Design Overview Medical Device Testing Timeline of Filter Design Fabrication & Packaging http://english.braile.com.br/produto-detalhes.asp?id=45

Home Overview IVC Filter Design Mouse over a component for more information. There are several features on most filters that contribute to its function. Retrieval Hook Filter Design Overview [D1] Primary Filter Leg Secondary Filter Leg Anchor/Foot http://www.bariatricnews.net/?q=news/research/prophylatic-ivc-filter-insertion-%E2%80%9Cmore-risks-benefits%E2%80%9D

Home Timeline IVC Filter Design Click the arrow to advance the timeline. You can also click on each filter for more info! Timeline of Designs [C2,C7,C10] Stainless Steel Greenfield (1973) Bird’s Nest (1982) Mobin-Uddin (1967) 1970 1975 1980 Current permanent filters Current retrievable filters

Home Timeline IVC Filter Design Titanium Greenfield (1989) Vena Tech LGM (1989) Simon Nitinol (1990) 1985 1990 1995

Home Timeline IVC Filter Design Celect (2008) TrapEase (2000) Vena Tech LP (2001) OptEase (2004) Günther Tulip (2003) ALN (2008) Option (2009) SafeFlo (2009) Crux (pending) G2 (2008) 2000 2005 2010 Click to learn more about the debate between permanent and retrievable IVC filters! The market trend has shifted to manufacturing of Retrievable Filters

Permanent vs. Retrievable Home IVC Filter Design Permanent filters are designed to hook permanently into the IVC wall. Over time, these filters become overgrown by cells from the IVC wall and there is a high risk of IVC injury if filter removal is attempted. Retrievable filters typically have smaller, thinner hooks and can be pulled back into a catheter and removed from the body, often through the jugular vein. Permanent vs. Retrievable Filters Newer designs and developments in insertion placement techniques mean that some filters can be left in for prolonged periods, and retrievals after a year are now being reported. Next http://www.cookmedical.com/di/datasheetFeature.do?id=4620

Permanent vs. Retrievable Home IVC Filter Design The Society of Interventional Radiology developed the following guidelines to see if someone qualifies for IVC filter removal: Indications for IVC Filter Removal [C4] • No need for permanent filter • Low risk of significant PE • Continuation of anticoagulation therapy • No expected near-term high risk PE • Life expectancy > 6 months • Ability to retrieve the filter • No complications, tear probability, or trauma • Patient consent Back to IVC Filter Design Michael Miller Jr., M.D. “Venous Disease and Management.” 2011.

Material Selection Home IVC Filter Design Click on each blue button to learn more! When a company develops a filter, they must balance what they need and want in a filter based on the materials that are available. Material Selection Wants Needs http://www.dymeintheruff.com/2010/11/official-dyme-scale-revisited.html Material Considerations Material Options

Material Selection Home IVC Filter Design Click on each button to learn more! What should a filter material be? What does a filter material need to be? Considerations [D2] http://www.wwiprocat.com/wwiprocat_seccion_detalle_ing.php?nid=1 http://www.krishnalounge.com/2009/12/human-body-and-cosmic-organism/ http://www.bvhealthsystem.org/?id=42&sid=1 MRI Compatible Non-corrosive Biocompatible Next: What are my options for materials? http://www.invitrogen.com/site/us/en/home/References http://disordersblood.net/blood-clotting-disorders/ Non-thrombogenic Durable

Material Selection Home IVC Filter Design Click on each button to learn more! All filters on the market are made of metal, but there are 5 different metals used… Options [D2,D4] http://en.wikipedia.org/wiki/File:Gateway_arch.jpg http://www.phiengineering.com/nitinol.htm http://www.cartech.com/products.aspx http://www.pinemeadowgolf.com/golf-clubs/irons/command.titanium.irons Cobalt- Chromium Alloys Titanium Alloys Nitinol Stainless Steel Material Options/Current Filter Summary

Fabrication Process Home IVC Filter Design Mouse over each step for a summary. Click on the summary for more details! How do companies make filters? Raw Material Receival Filter Forming Fabrication Process [D7] Thermosetting Packaging & Labeling Sterilization

Device Testing Home IVC Filter Design Click on the blue buttons to learn more! All IVC filters are defined as permanent implant, blood-contacting devices. They must meet specific biocompatibility and filter performance standards as outlined by the Food and Drug Administration. Medical Device Testing [C1] Pre-clinical testing: Biocompatibility Filter Performance Official Document “Manufacturers should demonstrate that the proposed device complies with the specific recommendations of this guidance...to provide assurances of safety and effectiveness.” http://www.fda.gov/MedicalDevices/DeviceRegulationandGuidance/GuidanceDocuments/ucm073776.htm

Device Testing Home IVC Filter Design Biocompatibility Testing [C1] Click on the bubbles to learn more! • Biocompatibility Cytotoxicity • The ability to perform with an appropriate response within the body and not cause the patient harm. Hemocompatibility Carcinogenicity Chronic Toxicity Implantation Genotoxicity Subchronic Toxicity Acute Systemic Toxicity Sensitization Irritation Back to Device Testing

Device Testing Home IVC Filter Design Thrombogenicity Introducer/ sheath suitability MRI compatibility Caval perforation/ filter migration Clot trapping ability Filter fracture Simulated deployment Click on the buttons to learn more! Filter Performance Testing [C1] http://www.sciencedirect.com/science/article/pii/S1350453311003195 Back to Device Testing

Home Implant Procedure Implant Procedure Filter Selection Filter Retrieval When to Implant Procedure Details Main Menu http://www.drugs.com/cg/inferior-vena-cava-filter-placement.html

Home When to Implant Implant Procedure Do you need an IVC filter? Take the interactive questionnaire Proceed straight to flowchart

Home When to Implant Implant Procedure Do you need an IVC filter? [C5] Return to Procedure menu Do you have documented DVT/PE? YES NO • Do you have any of the below? • Absolute contraindication to anticoagulation • Documented progression of DVT or recurrent PE while anticoagulated • Complication of anticoagulation requiring termination of therapy • Failure of existing IVC filter (recurrent PE) and continued contraindication to anticoagulation • Massive PE that requires surgical thromboectomy • Do you have any of the below? • High risk of developing DVT/PE (e.g., multiple trauma) • Past history of DVT/PE undergoing surgical procedure with high risk of postoperative DVT/PE YES NO YES NO YES You might benefit from an IVC filter. (Please consult your doctor.) NO You probably do not need an IVC filter. (Please consult your doctor.)

Home When to Implant Implant Procedure There are so many different IVC filters. Which one will you receive? [C6,C9] Duke Hospital uses the filters it considers are the best or have distinct advantages. IVC filter patients at Duke receive one of the following, in order of commonality: Option (Rex Medical) Celect (Cook Medical) OptEase (Cordis) Choice between Celect and Option is usually the preference of the operator Very small introducer (one of the smallest on the market), holds very tight to caval wall Only filter than can be removed femorally Return to Procedure menu Note that all three are retrievable. 40% of the filters placed at Duke are retrieved (no longer needed).

Home Implant Procedure Procedure Details Click on each question box for more information. What comes in an IVC Filter kit? Filter Placement Procedure What happens during the procedure? How is the implant location chosen? What complications can occur during the procedure? What happens after the procedure? Modified from http://www.youtube.com/watch?v=UvtHCMBm0SA Back to Implant Procedure

Home Implant Procedure Procedure Details • What Complications Can Occur During the Procedure? [A2,A3] Click each for more information Sheath perforation Introducer tip detachment Filter deformation/ fracture Premature release or incomplete opening Improper placement Sheath/Guidewire kinking Guidewire Entrapment Can result in… For more information about potential complications with the filter after implantation, visit the “IVC Performance & Failure Section” Back to Procedure Details

Home Implant Procedure Procedure Details Mouse over each box for more information. There is no regular check-up schedule for patients with an IVC Filter. What Happens After the Procedure? [D1,D9] Most patients go home shortly after the procedure is complete. http://www.ivcfilter.northwestern.edu/patient-populations/trauma/

Home Implant Procedure Filter Retrieval Filters are not always retrieved, but they may be retrieved if the patient’s risk factors are no longer an issue. If the filter is retrieved, the following procedure is followed: • 1. Initial steps are similar to those in the placement procedure. • Local anesthetic injected at incision site. • Incision made and contrast agent injected. • Guide wire and dilator used to get to filter site. Filter Retrieval [D1,D9] Modified from http://www.cookmedical.com/di/datasheetMedia.do? mediaId=4060&id=4355 Play Animation Next Step

Home IVC Filter Performance & Failure IVC Filter Performance & Failure Failure Modes Filter Performance General Controversy http://bhagia.wordpress.com/article/the-puerperium-question-answers-1phs16i73la7p-110/ Main Menu

Filter Performance Home IVC Filter Performance & Failure Filter Performance [B7] Clinically preferred zone of clot retention • The Basics of Blood Flow Dynamics: • Blood flows faster in the center of the vein than it does near the walls • Thrombi erode most efficiently in a high-flow environment, so an ideal IVC filter arrests clots in the center of the venous flow pattern • Most IVC filters implement cone-shaped designs to suspend the clot in the center of the vessel Flow velocity decreases in proportion to proximity to the vessel wall Next

Filter Performance Home IVC Filter Performance & Failure Filter Performance [B8] Traditional cone-shaped filters trap clots in the high-flow zone by “funneling” them to the filter tip while allowing non-clotted cells to pass through. As clots occlude the vessel, blood flow and clot formation is directed to the sides where filtering capacity is lower. View Animation View Animation View Animation Next

Filter Performance Home IVC Filter Performance & Failure Filter Performance [B8] View Animation Hexagonal filters echo the cone-shaped design on the upstream and downstream ends, allowing for both inferior and superior implantation. In this design, clots initially tend to be arrested on the cava walls and the filter on the upstream side. This is undesirable from a clinical standpoint because the clot is exposed to lower velocity flow in these areas. Interestingly, hexagonal filters become progressively better filters as the previous occlusions direct subsequent flow toward the center of the vessel. Next

Filter Performance Home IVC Filter Performance & Failure Filter Performance [B8] Filter construction can significantly impact blood flow. Hexagonal filters (Cordis’ OptEaseand TrapEase) initially induce a diverging force at the upstream end of the filter that pushes clots to the outside of the vein, where blood flow is slower and clot erosion is less efficacious. Next http://www.jvir.org/article/S1051-0443%2809%2900201-2/abstract

Filter Performance Home IVC Filter Performance & Failure Filter Performance [B8] These filter types actually become better filters as more thrombi are arrested at the upstream (bottom) end, as subsequent clots are forced through the higher-velocity central flow region where erosion is more efficient. Next http://www.sciencedirect.com/science/article/pii/S1051044309002012

Filter Performance Home IVC Filter Performance & Failure Filter Performance [B8] Intimal hyperplasia Intimal hyperplasia is a physiologic healing response to injury to the blood vessel wall. When the endothelium is injured, endothelial cells release inflammatory mediators that promote smooth muscle cell migration from the media to the intima resulting in swelling of the cell wall and stenosis (narrowing) of the vessel. A number of strategies are under investigation to reduce intimal hyperplasia. Including drug-eluting implants and low-dose, low molecular weight anticoagulants. http://radiopaedia.org/articles/intimal-hyperplasia Next

Filter Performance Home IVC Filter Performance & Failure Filter Performance [B8] Cone-shaped filters Only the distal hooks of the filter struts are in contact with the vena cava wall, so a lesser degree of hyperplasic embedding occurs. Hexagonal filters Filter struts lie parallel against the vena cava wall. This benefits filter stability, but allows for greater contact with the vena cava wall, increasing the likelihood of intimal hyperplasia. View Animation View Animation Back to IVC Performance & Failure Menu

Failure Modes Home IVC Filter Performance & Failure Failure Modes Screnshot: http://www.youtube.com/watch?v=qlaDA_FRA48 http://www.sciencedirect.com/science/article/pii/S1443950609011135 http://www.carincain.com/home/detail.php?detailid=802 Penetration Tilting Fracture Occlusion Migration Greenfield Filter obstructed by renewed thrombus formation http://www.uwmedicine.org/patient-care/our-services/medical-services/radiology-imaging-services/pages/articleview.aspx?subId=245 http://legalmedicalexhibits.com/90027-application-of-greenfield-filter-p-820.html Back to Performance & Failure Menu

Failure Modes Home IVC Filter Performance & Failure Caval Penetration [A2,A3] Penetration of inferior vena cava wall by filter prongs Penetration Back to Failure Modes

Failure Modes Home IVC Filter Performance & Failure Fracture[A2] Individual struts of the filter fail and cause malformation of the device Arm & Leg Fracture Foot Fracture Click to see example of fractured filter removal Back to Failure Modes

Failure Modes Home IVC Filter Performance & Failure Fracture: Surgery [A4] http://www.sciencedirect.com/science/article/pii/S1051044311013601 Back to Failure Modes

Inferior Vena Cava Filters (IVCFs)