Despite the paucity of randomized controlled trials and strong observational studies supporting the efficacy of inferior vena cava filters (IVCFs) in venous thromboembolism (VTE) prevention, indications for placement of IVCFs have increased. Further, evidence-based guidelines for removal of retrievable filters do not exist. The purpose of this study was to characterize contemporary IVCF practices in the prevention and management of VTE, and clarify the stakeholders in IVCF placement and retrieval among trauma centers across the United States.
In September 2011 a web-based survey was distributed to 1206 members of the Eastern Association for the Surgery of Trauma (EAST) in 3 waves over 3 weeks. This 31-question multiple choice and open-ended survey addressed: 1) provider and practice characteristics, 2) trauma patient population, 3) clinical practice of IVCF placement and retrieval, and 4) pharmacologic prophylaxis (PP).
Of the 1059 eligible providers that care for trauma patients on a routine basis, 281 completed the survey (27% response rate); 27% were identified as trauma directors. Seventy-two percent of all responents practiced in an academic setting and 74.7% in a level-1 trauma center. Sixty percent of trauma directors reported more than 1,000 trauma admissions per year. Familiarity with the 2002 EAST and 2008 American College of Chest Physicians guidelines for IVCF placement was noted by 84.3% and 63.0% of respondents, respectively.
The majority of trauma centers placed IVCFs (98.9%), of which 3.6% placed only permanent IVCFs, 27.3% only retrievable IVCFs, and 67.3% both. Only 28.4% of centers had an institutional clinical protocol for IVCF placement and 25.5% for removal of IVCFs. The most common indication for IVCF placement was acute VTE and contraindication to therapeutic anticoagulation (32.4%). Prophylactic IVCFs (pIVCFs) in high-risk patients without known VTE were utilized by 97.6% of respondents. Indications for pIVCFs included inability to receive PP (26.5%), incomplete spinal cord injury (19.8%), and complex pelvic fracture with long bone fracture (19.6%). Filter insertion was performed by interventional radiologists (48.1%), vascular surgeons (35.6%), and/or trauma surgeons (15.5%) at each institution. Ultrasound guidance was used in 23.3% of IVCFs placed and 14.0% of insertions occured at the bedside. Acute and long-term complications encountered by providers included filter migration (21.0%), recurrent VTE (15.5%), hematoma (15.5%), and inferior vena cava thrombosis (13.8%). Surveillance for lower extremity deep vein thromboses in trauma patients was performed by 52% of centers.
A registry to track patients with IVCFs was maintained by 38% of centers. Decisions to refer patients for IVCF removal were made by the proceduralist service (37.7%), ordering service (38.7%), and/or service following patients after discharge (12.7%). Only 2.5% of respondents removed IVCFs prior to hospital discharge. Screening for VTE prior to IVCF removal was performed with ultrasound (28%), venogram (14.4%), or computed tomography (2.5%), however 43.3% were uncertain of the screening method.
In addition to IVCFs, adjunctive VTE prophylaxis indicated by respondents were sequential compression devices (26.7%), low molecular weight heparin (39.0%), unfractionated heparin (25.2%), fondaparinux (5.4%), or aspirin (2.0%). Only 1% of respondents indicated not using PP in trauma patients with IVCFs. Formal institutional PP guidelines existed in 92.9% of institutions. The most common reasons for contraindication to PP included pelvic or retroperitoneal hematoma requiring transfusion of blood products (20.0%), traumatic brain injury (18.3%), ocular injury with hemorrhage (16.3%), coagulopathy (13.6%), and solid intra-abdominal organ injury (11.4%). Sixty-one providers (7.1%) did not indicate any absolute contraindications for PP outside of acute phase of the above injuries.
This study confirms the widespread use of IVCFs for both acute VTE and prophylactic indications. However, considerable variation in practice patterns with regards to institutional protocols for IVCF placement and retireval as well as utilization of adjunctive pharmacologic prophylaxis exists. These differences highlight the need for well-designed randomized controlled trials to address the efficacy and safety of IVCFs in trauma patients.
No relevant conflicts of interest to declare.
Asterisk with author names denotes non-ASH members.