Inferior Vena Cava Filter Placement Patterns: Our experience and a review of the literature Jaideep Patel, Stephanie Detterline, M.D., Robert Ferguson, M.D. ACP Internal Medicine 2010 – Toronto, April 24th, 2010

Available data  case reports, with few animal or in vitro studies, reviews, and prospective studies Only 1 RTC available  Decousus et al Pts with DVT (w/ or w/o PE) randomized to receive  Filter vs no filter Also all patients were anticoagulated for 3 months. filter group had a significantly lower incidence of PE during the first 12 days than the non-filter group. May benefit patients with high risk PE  overlooked that IVC filters have their own inherent risks and complications and may not be the best management strategy for every patient

Concerning because it has great implications for both patient safety and proper utilization of resources.

National Hospital Discharge Survey (1979-1999) Numbers begin to increase sharply in 1988 Increasing use of filters, with development in filter technology (Nonthromogenic, High filtering efficiency , Retrievable) ----------- large and small emboli (without impedance of flow) Secure fixation within the vena cava Rapid percutaneous insertion Smaller caliber Amenable to repositioning Simple release mechanism MRI compatible Low cost Retrievable 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.

Objective Review our institutional practices regarding IVC filter placement and compare this to available published guidelines to better understand our compliance with the available evidence. Want to ensure we are appropriately placing IVC filters because according to the NEJM study, having an IVC filter shows no effect on survival WANTED TO ASSES OUR USE of IVC FILTERS IN OUR INSTITUTION

Methods Retrospective review of patients undergoing temporary or permanent IVC filter implantation from 2001 to 2009. Demographics, clinical presentation, indications for placement according to ACCP (2008) and extended guidelines, filter type, and hypercoagulable risk factors were collected for each case.

Methods In each case, indications for IVC filter placement were determined to be either: Indicated by absolute guidelines (G) Indicated by relative guidelines (EG) Met neither criteria for placement (NG) Also on a case by case basis, IVC filter placement was determined to be

Absolute Guidelines for IVC Filter Placement - ACCP(2008) Proven VTE with contraindications for anticoagulation Proven VTE with complications of anticoagulation treatment Recurrent VTE despite anticoagulation treatment (failure of anticoagulation) Adapted from Chest 1,2

Relative extended guideline indications for IVF Filter placement Recent VTE and operative procedure requiring prolonged withholding of anticoagulation Patients with DVT and limited cardiopulmonary reserve or COPD Patients with DVT who have cancer, burns or are pregnant Large/free floating iliofemoral thrombus in high risk patient Following thrombectomy/embelectomy/thrombolysis of a DVT Propagating iliofemoral thrombus while anticoagulated High risk surgical patients with anticoagulation contraindication Major abdominal surgery within the past 2 days Gastrointestinal or genitourinary bleeding within the past 14 days Chronic PE in patient with pulmonary hypertension and cor pulmonale Malignant hypertension Infective endocarditis Adapted from Blood , J Vasc Interv Radio , Am J Med  Unfortunately, the ACCP Guidelines, are not clear in the definitions of what a contraindications or complications are, and for that reason  many who argue there are other compelling reasons for filter placement  Other than the ABSOLUTE recommended guidelines, there is also a list of RELATIVE guidelines  Often mentioned, but not widely agreed upon and include - read off two of them keep in mind NOT absolute  once again NOT ABSOLUTE

Total Filters Placed During Study Period Results: Total Filters Placed During Study Period Overall INCRESING trend in total number of filters placed * Data collected until September 2009

Results Fully 50% of our filters were guideline indicated, and the remaining ½ were either EG or NG Of our 50% that followed absolute guidelines for placement , 50% were placed in patients who had an acute VTE and a contraindication for IVC placement

Contraindications to Anticoagualtion Therapy If we break down the contraindications to IVC filter placement in our study Major risk of falling n=40 33.3% Overt GI bleed/guiac positive stools n=24 20.0% 1/3 of these filters were not placed due to patient having a high risk of fall This was followed closely by patients being heme positive

Complications of Anticoagulation Therapy 97% of patients encountered bleeding as their complication to AC therapy, and hence received a filter

Results 27% of our patients had filters placed according to the Relative Guidelines for IVC Filter placement

Relative Indications for Placement In regards to RELATIVE Guidelines, 27% 71% of our patients had an IVC filter placed due to the fact that they were undergoing an operative procedure which required holding of AC Attribute it to Union being a surgical center, with a stellar orthopedic unit

Conclusions 50% Indicated by absolute guidelines (G) 27% Indicated by relative guidelines (EG) 23% Met neither criteria for placement (NG) In summary, 50% of our patients had IVC filters placed according to current ACCP guideline What was concerning to us though was the 23% of patients who met neither criteria for IVC filter placement Concerning from a safety standpoint, given that IVC filters have shown no effect on survival

Conclusion Our practices our comparable Limitations Physician understanding Unclear recommendations/guidelines Poor dictation Patient follow-up Kalva (2006) – study from Mass General – 28% prophylaxis; 72% G Moris (2004) – study from U. of Vermont - 48% prophylaxis; 52% G Dorvish et all (2005) – 27% prophylaxis; 73% G – Israeli multicenter study Hammond et al (2008) – 57% G; 37% R; 6% prophylaxis – UK multicenter study Ivette (2007) – 13.6% Prophylaxis; 71% G; 12.2% R – Chilean study Singh et al (2009) - 65% WG, 35% OOG - US Given this data, we seem to fall within the range at which other hospitals are placing IVC filters outside of the accepted guidelines However, we feel a great need for more research on the proper indications, and greater attention to enforce those already in existence Future studies Patient follow-up