Long-term follow-up of trauma patients with permanent prophylactic vena cava filters

Risk factors of nonretrieval of retrievable inferior vena cava filters

BACKGROUND

Optimal use of retrievable inferior vena cava (IVC) filters is an important health care issue, and despite an exponential rise in the use of retrievable IVC filters, national trends suggest that most of these filters are not removed. The purpose of this study was to identify risk factors associated with nonretrieval of retrievable IVC filters at our institution.

METHODS

A retrospective institutional review of all patients undergoing IVC filter placement from June 2010 to June 2012 was performed. A number of patient parameters were studied, including relevant demographics, indication for filter placement, clinical history, related hospitalization, and whether filter retrieval was performed. Patient parameters were compared by univariate and multivariate logistic regression analyses.

RESULTS

There were 605 retrievable IVC filters placed over a 24-month period by vascular surgery, intervention radiology, and interventional cardiology. The follow-up retrieval rate was 25%. By indication, 272 (45%), 53 (9%), and 280 (46%) filters were placed for absolute, relative, and prophylactic indications, respectively. Independent predictors for nonretrieval by multivariate analysis were age >80 years (hazard ratio [HR], 5.0; 95% confidence interval [CI], 1.7-20; P < 0.001), acute bleed (HR, 2.5; 95% CI, 1.4-5; P < 0.001), current malignancy (HR, 2.0; 95% CI, 1.3-3.3; P = 0.011), postfilter anticoagulation (HR, 0.5; 95% CI, 0.28-0.9; P = 0.017), and history of pulmonary embolism and/or venous thromboembolism (HR, 0.5; 95% CI, 0.28-0.35; P < 0.001). Filter placement team and indication were not identified as independent predictors of nonretrieval of IVC filters.

CONCLUSIONS

Patient variables identified by univariate and multivariate analyses as risk for nonretrieval of retrievable IVC filters have several implications: first, some of these patients may represent a group of patients with a low life expectancy or unresolvable underlying condition in which filter retrieval has diminishing returns and may indicate the clinical option for permanence of the filter; second, identification of risk factors for nonretrieval in patients before filter placement will help to optimize use of retrievable IVC filters and enhance retrieval rates.

Pharmacologic venous thromboembolism prophylaxis after traumatic brain injury: a critical literature review

Despite the frequency and morbidity of venous thromboembolism (VTE) development after traumatic brain injury (TBI), no national standard of care exists to guide TBI caregivers for the use of prophylactic anticoagulation. Fears of iatrogenic propagation of intracranial hemorrhage patterns have led to a dearth of research in this field, and it is only relatively recently that studies dedicated to this question have been performed. These have generally been limited to retrospective and/or observational studies in which patients are classified in a binary fashion as having the presence or absence of intracranial blood. This methodology does not account for the fact that smaller injury patterns stabilize more rapidly, and thus may be able to safely tolerate earlier initiation of prophylactic anticoagulation than larger injury patterns. This review seeks to critically assess the literature on this question by examining the existing evidence on the safety and efficacy of pharmacologic VTE prophylaxis in the setting of elective craniotomy (as this is the closest model available from which to extrapolate) and after TBI. In doing so, we critique studies that approach TBI as a homogenous or a heterogenous study population. Finally, we propose our own theoretical protocol which stratifies patients into low, moderate, and high risk for the likelihood of natural progression of their hemorrhage pattern, and which allows one to tailor a unique VTE prophylaxis regimen to each individual arm.

Risk factors for venous thromboembolism in critically ill trauma patients who cannot receive chemical prophylaxis

BACKGROUND

Standard venous thromboembolism (VTE) prevention for critically ill trauma patients includes sequential compression devices and chemical prophylaxis. When contraindications to anticoagulation are present, prophylactic inferior vena cava filters (IVCF) may be used to prevent pulmonary emboli (PE) in high-risk patients, but specific indications are lacking. We sought to identify independent predictors of VTE in critically-ill trauma patients who cannot receive chemical prophylaxis in order to identify a subset of patients who may benefit from aggressive screening and/or prophylactic IVCF placement.

METHODS

All trauma patients in the surgical ICU from 2008 to 2009 were prospectively followed. Patients with an ICU length of stay ≥2 days who had contraindications to prophylactic anticoagulation were included. Screening duplex exams were obtained within 48 h of admission and then weekly. CT-angiography for PE was obtained if clinically indicated. Patients were excluded if they did not receive a duplex or if they had a post-injury VTE prior to ICU admission. Data regarding VTE rates (lower extremity [LE] DVT or PE), demographics, past medical history (PMH), injuries, and surgeries were collected. Univariate and multivariable analyses were performed to identify independent predictors of VTE with a p<0.05.

RESULTS

411 trauma patients with a mean age of 48 (SD 22) years and 8 (SD 9) ICU days were included. 72% were male and the mean ISS was 22 (SD 13). 30 (7.3%) patients developed VTE: 28 (6.8%) with LEDVT and 2 (0.5%) with PE. Risk factors for VTE with a p<0.2 on univariate analysis included: PMH of DVT, injury severity score (ISS), extremity fractures (Fx), and a pelvis or LE extremity Fx repair. After logistic regression, only PMH of DVT (OR=22.6) and any extremity Fx (OR=2.4) remained as independent predictors.

CONCLUSION

VTE occur in 7% of critically injured trauma patients who cannot receive chemical prophylaxis. Aggressive screening and/or prophylactic IVCF placement may be considered in patients with a PMH of DVT or extremity fractures when anticoagulation is prohibited.

Vena cava filter practices of a regional vascular surgery society

BACKGROUND

Vena cava filter (VCF) use in the United States has increased dramatically with prophylactic indications for placement and the availability of low-profile retrievable devices, which are overtaking the filter market. We surveyed the practice patterns of a large group of vascular surgeons from a regional vascular surgery society to see whether they mirrored current national trends.

METHODS

A 17-question online VCF survey was offered to all members of the Southern Association of Vascular Surgery. The responses were analyzed using the χ(2) goodness of fit tests.

RESULTS

Of the 276 members surveyed, 126 (46%) responded, with 118 (93%) indicating that they placed filters during their practice. Highly significant differences were identified with each question (at least P < 0.002). Regarding the inferior vena cava, the preferred permanent filters were the Greenfield (31%), the TrapEase (15%), the Vena Tech (5%), and a variety of retrievable devices (49%). Fifty percent of the respondents placed retrievable filters selectively; 26% always placed them; and 24% never did. Filters were placed for prophylactic indications <50% of the time by 63% of the respondents. Overall, retrievable filters (when not used as permanent filters) were removed <25% of the time by 64% of the respondents and <50% of the time by 78% of the respondents. The femoral vein was the preferred access site for 84% of the respondents. Major complications were few but included filter migration to the atrium (one), atrial perforation (one), abdominal pain requiring surgical filter removal (two), inferior vena cava thrombosis (12 vena cava thrombosis--4 due to TrapEase filters), strut fracture with embolization to heart or lungs (three Bard retrievable filters), and severe tilting precluding percutaneous retrieval and protection from pulmonary emboli (8 filters with severe tilt--7 of which were Bard). Of the respondents, 59% had never placed a superior vena cava filter, and 28% had placed five or fewer.

CONCLUSIONS

Although VCF insertion overall appears safe, some complications are specific to biconical and certain retrievable filters. Given the low removal rate and lack of long-term experience with retrievable filters, routine use of these devices as permanent filters should be questioned. If used on a temporary basis, there should be a plan for filter removal at the time of implantation.

Deep vein thrombosis prophylaxis in trauma patients

Deep vein thrombosis (DVT) and pulmonary embolism (PE) are known collectively as venous thromboembolism (VTE). Venous thromboembolic events are common and potentially life-threatening complications following trauma with an incidence of 5 to 63%. DVT prophylaxis is essential in the management of trauma patients. Currently, the optimal VTE prophylaxis strategy for trauma patients is unknown. Traditionally, pelvic and lower extremity fractures, head injury, and prolonged immobilization have been considered risk factors for VTE; however it is unclear which combination of risk factors defines a high-risk group. Modalities available for trauma patient thromboprophylaxis are classified into pharmacologic anticoagulation, mechanical prophylaxis, and inferior vena cava (IVC) filters. The available pharmacologic agents include low-dose heparin (LDH), low molecular weight heparin (LMWH), and factor Xa inhibitors. Mechanical prophylaxis methods include graduated compression stockings (GCSs), pneumatic compression devices (PCDs), and A-V foot pumps. IVCs are traditionally used in high risk patients in whom pharmacological prophylaxis is contraindicated. Both EAST and ACCP guidelines recommend primary use of LMWHs in trauma patients; however there are still controversies regarding the definitive VTE prophylaxis in trauma patients. Large randomized prospective clinical studies would be required to provide level I evidence to define the optimal VTE prophylaxis in trauma patients.