Evaluation of inferior vena cava filter retrieval following implementation of dedicated tracking system. Emily Johnson, Justin Siegal, Robert Crane, Elizabeth Thompson, C Craig Blackmore
Disclosures C Craig Blackmore Book royalties: Evidence Based Imaging Springer Publishing.
Purpose August 2010- US Food and Drug Administration safety communication Urge removal of vena cava filters (VCF) Nationally extremely low retrieval rates Safety concerns This study assesses the effectiveness of implementation of VCF registry and follow up protocol on VCF retrieval rates. 3
Quality Improvement Project Sept 2012-quality improvement project (QIP) begins Centralized registry for VCF patients Resolved Filter deemed permanent Filter removed Patient deceased Unresolved Pending clinical circumstances Lost to follow up 4
Quality Improvement Project Interventional Radiology VCF nurse coordinator Maintain VCF registry Add patients using HI-IQ database Update patient VCF status Review medical record to assess patient clinical status Standardized email update to IR physician Date of filter placement Initial indication Referring provider information Standard options for response Standardized follow-up Potential retrieval discussed in consent process Post procedure information given to patient regarding retrieval Patient encouraged to contact referring provider Letter to referring provider 1 month post placement Communication between IR physician and referring provider 5
Method Retrospective cohort study All VCF January 2004 - March 2014 Patient data collected through review of individual patient charts Analysis: Interrupted time series regression adjusted for autocorrelation 6
Results- Demographics Jan 2004 -March 2014 662 filters placed Females - 51% Mean Age - 67.6 years QIP - Sept 2012 Year Total # Filters Female, # Female, % Mean Age, Years 2004 60 27 45.0% 65.7 2005 63 39 61.9% 69.1 2006 68 39 57.4% 70.5 2007 66 37 56.1% 68.5 2008 58 27 46.6% 68.6 2009 71 28 39.4% 66.8 2010 52 33 63.5% 64.8 2011 48 20 41.7% 68.2 2012, total 66 35 53.0% 67.4 2012, Pre 34 15 44.1% 66.4 2012, Post 32 20 62.5% 68.6 2013 76 31 40.8% 64.5 2014 34 20 58.8% 69.7 Pre QIP 520 265 51.0% 67.6 Post QIP 142 71 50.0% 67.6 Total 662 336 51.3% 67.6 Table 1: Patient Demographics by Year
Results- Filter Types Year Total # Filters Bird's Nest Trapease Gunther Recovery Tulip Optease Option Celect Meridian Denali 2004 60 0 42 3 15 0 0 0 0 0 0 2005 63 0 33 2 27 1 0 0 0 0 0 2006 68 2 18 13 17 5 13 0 0 0 0 2007 66 3 15 3 2 8 34 0 1 0 0 2008 58 0 0 3 0 2 34 0 19 0 0 2009 71 0 0 1 0 1 11 5 53 0 0 2010 52 0 0 0 0 0 2 0 50 0 0 2011 48 0 0 0 0 0 0 0 48 0 0 2012 66 0 0 0 0 0 0 0 29 37 0 2013 76 0 0 0 0 0 0 0 2 39 35 2014 34 0 0 0 0 0 0 0 3 1 30 Table 2: Type of Filter by Year. Bird s Nest and Trapease type filters are non-retrievable by design and cannot be removed. The remainder of filter types are retrievable. 8
Results- Filter Types Graph 1: Number of retrievable and non-retrievable filters over time. Retrievable filters were introduced in 2003. Nationally, by 2006 retrievable filters made up half of the market and were increasing in numbers placed. 9
Results- Retrieval Retrievable Retrievable Remove Attempt Total # type filter type filter Remove Remove Attempt %, Retrievable type Time to Year Filters # % Attempt # %, All filters filters Retrieval, days 2004 60 18 30.0% 11 18.3% 61.1% 41.2 2005 63 30 47.6% 9 14.3% 30.0% 27.4 2006 68 48 70.6% 11 16.2% 22.9% 24.1 2007 66 48 72.7% 13 19.7% 27.1% 53.1 2008 58 58 100.0% 13 22.4% 22.4% 24.8 2009 71 71 100.0% 25 35.2% 35.2% 50.5 2010 52 52 100.0% 21 40.4% 40.4% 45.0 2011 48 48 100.0% 16 33.3% 33.3% 54.9 2012, total 66 66 100.0% 23 34.8% 34.8% 88.4 2012, pre 34 34 100.0% 14 41.2% 41.2% 87.2 2012, post 32 32 100.0% 9 28.1% 28.1% 90.1 2013 76 76 100.0% 33 43.4% 43.4% 50.8 2014 34 34 100.0% 12 35.3% 35.3% 56.2 Pre QIP 520 407 80.1% 133 26.8% 34.8% 45.4 Post QIP 142 142 100.0% 54 35.6% 35.6% 65.7 Total 662 549 83.7% 187 28.5% 35.1% 46.9 Table 3: Filter Retrieval Attempts by Year. A trend is present for both proportion of retrievable stents placed over time as well as the number of attempted retrieval.
Results- Retrieval VCF retrieval rate: 18.3% in 2004 40.9% last 4 quarters (April, 2013-March, 2014) Increase of 0.88 percentage points per quarter (p<.001, 95% CI: 0.57-1.19). Graph 2: Proportion of all filters (retrievable and non-retrievable) with removal attempt. Open circles represent pre-qip and closed circles are post-qip. 11
Results- Retrieval However, after adjusting for filter type (retrievable vs non-retrievable) and the underlying temporal trend, there was no significant change in the retrieval rate with implementation of the QIP, p= 0.270. No significant change if exclude filters placed prior to 2006, p= 0.180. Graph 3: Proportion of retrievable type filters with removal attempt. Open circles represent pre-qip and closed circles are post-qip. Red open circles are filters placed before 2006 when retrievable filters made up <50% of all filters 12 placed.
Results Following the QIP Only 2.1% were lost to follow up 9.6% (18/187) failed retrieval rate Primarily due to thrombus in the IVC Time to retrieval Pre-QIP 45.4 days Post-QIP 65.7 days No statistical difference 13
Conclusion We observe a marked improvement in VCF filter retrieval rates between 2004 and 2014. However, despite numerous publications citing the efficacy of creating a centralized database for improving VCF retrieval rates, after adjustment for underlying trends and filter type, we found no significant difference in retrieval rate before and after implementation of the QIP. By creating a centralized database, we were able to achieve a very high rate of patient follow up. 14