Clinical Outcomes After Inferior Vena Cava Filter (IVCF) Placement in Cancer Patients: A Retrospective Study.
Authors: Narayan Anand , Kim Hyun , Hong Kelvin , Lee Adrea , Streiff Michael B. 
Published: October 2019

Abstract
Abstract 1076
Poster Board I-98

Purpose:
Cancer patients are at increased risk for recurrent venous thromboembolism (VTE) and bleeding during anticoagulation. Therefore, inferior vena cava filters (IVCF) are likely to be considered in VTE treatment in cancer patients. There are few data available to determine the safety and efficacy of IVCF in cancer patients. The purpose of this study was to compare the outcome of patients with and without cancer after IVCF placement.

Materials and Methods:
After institutional review board approval was obtained, consecutive patients who received an IVCF at the Johns Hopkins Hospital were identified using Current Procedural Terminology (CPT) codes. Demographic and clinical data were retrieved from the institutional electronic medical record (EMR). Clinical events including objectively-documented VTE were confirmed by an independent review of the EMR by two investigators. The outcome of patients with and without cancer was compared using compared using non-parametric and parametric statistics. Marginal structural models were used to model the impact of anticoagulation on VTE.

Results:
Between January 1, 2002 and December 31, 2006, 702 patients had an IVCF placed at the Johns Hopkins Hospital. 220 patients (31.3%) had cancer. The median age of the patients with and without cancer was 64 and 55 years, respectively (p < 0.001). Women constituted 47% of patients with and without cancer. 72.6% of patients with and 53.5% without cancer were Caucasian (p < 0.001). The most common cancer types were 77 gastrointestinal cancers (34.5%), 29 genitourinary cancers (13.0%) and 29 gynecologic cancers(13.0%). Metastatic disease was present in 49.5%. Mean follow up was 434 days (range 1 to 2638) for the overall study population and 262 days (1 to 2546) for cancer patients and 524 days (1 to 2638) for non cancer patients. 342 patients (48.8%) died during follow up. Cancer patients were more likely to receive filters for contraindications to anticoagulation and less likely for primary prophylaxis than non-cancer patients (p = 0.024). Cancer patients were more likely to present with pulmonary embolism (PE) (p < 0.001) and IVC thrombus (p = 0.043). Permanent IVCF were more commonly used in cancer patients (48.1% vs 34.6%, p < 0.001). For both cancer and non-cancer patients, the Optease filter was most commonly used retrievable filter (37.1%) while the Trapease filter was the most commonly used permanent filter (30.5%). Anticoagulation (AC) after IVCF placement was used in a similar proportion of cancer and non-cancer patients (42.7% vs. 37.6%, p=0.19). During follow up, 134 patients (19%) experienced VTE events (103 deep vein thrombosis [DVT], 35 pulmonary embolism [PE], 28 IVC thrombosis [IVCT]) Cancer patients were equally likely to suffer DVT (17.4% vs. 13.3%, p = 0.139) and PE (5.8% vs. 4.6%, p = 0.473) as non-cancer patients, but more likely to develop IVCT (6.2% versus 2.8%, p = 0.029). Among 103 cancer patients who were treated with AC post-IVCF, 34(33.0%) developed VTE compared with 40 of 173 non-cancer patients (23.1%) (p=0.07).

Conclusions:
Our retrospective cohort indicates that IVCF are commonly used to treat VTE in cancer patients. VTE was common after IVCF placement. Compared with patients without cancer, cancer patients were equally likely to suffer DVT or PE but more likely to develop IVCT post-IVCF placement. AC post-filter placement did not appear to be protective against VTE and there was a trend toward more VTE among cancer patients despite AC. These data suggest that IVCF may result in more thrombotic events in cancer patients and should be reserved for patients with acute VTE and contraindications to anticoagulation. Prospective studies are warranted to confirm these data.

Disclosures:
No relevant conflicts of interest to declare.