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1795. External Validation of a Quantitative Model to Guide Patient Selection for Placement of an Optional or Permanent IVC Filter
Authors * Denotes Presenting Author
  1. Eric Keasler; University of Alabama at Birmingham
  2. S Brown; University of Alabama at Birmingham
  3. Junjian Huang; University of Alabama at Birmingham
  4. Aliaksei Salei *; University of Alabama at Birmingham
  5. Theresa Caridi; University of Alabama at Birmingham
  6. Kush Desai; Northwestern
  7. Andrew Gunn; University of Alabama at Birmingham
Objective:
To externally validate a previously published quantitative model (1) that predicts the likelihood of an optional inferior vena cava filter (IVCF) being kept as a permanent device against a different patient population.

Materials and Methods:
An institutional database of IVCF patients from 2016-2018 was reviewed. As in the published reference (1), if a retrieval was attempted, the IVCF was categorized in the removal group; if no attempt was performed, the filter was categorized as permanent. As in the reference, parameters, such as age, sex, history of venous thromboembolism (VTE), presence of neurologic disease, presence of malignancy, as well as indications for IVC filter placement were collected and analyzed. The previously published formula was applied to this patient population to analyze its ability to predict the likelihood of a retrievable IVCF being kept as a permanent device in a new, external population.

Results:
A total of 291 patients with optional IVCFs were identified (F=135; M=156). 73 filters were retrieved and 218 were kept permanently. Advanced age was the only factor associated with the IVCF being kept permanently versus retrieved (odds ratio (OR) 1.05; 95% confidence interval (CI) 1.03-1.07). None of the other parameters, including sex, history of VTE, presence of neurologic disease, presence of malignancy, or indication for IVCF placement, was statistically significant. The receiver operator characteristic curve for the prediction model based on the previously published formula yielded the area under the curve of 0.68, compared to the previously published value of 0.8. The sensitivity and specificity of the prediction model was 67.3% and 60.3%, respectively.

Conclusion:
Advanced age was associated with optional IVCFs being kept as permanent devices, which could be used for decision-making at the time of placement. However, the previously published formula did not yield an accurate quantitative prediction in this external patient population. Improved decision support tools are needed when selecting between permanent and optional IVCFs.