Selective venography versus nonselective venography before vena cava filter placement: evidence for more, not less

Complications of inferior vena cava filters

Inferior vena cava (IVC) filter placement is a relatively low risk alternative for prophylaxis against pulmonary embolism in patients with pelvic or lower extremity deep venous thrombosis who are not suitable for anticoagulation. There is an increasing trend in the number of IVC filter implantation procedures performed every year. There are many device types in the market and in the early 2000s, the introduction of retrievable filters brought an additional subset of complications to consider. Modern filter designs have led to decreased morbidity and mortality, however, a thorough understanding of the limitations and complications of IVC filters is necessary to weight the risks and benefits of placing IVC filters. In this review, the complications associated with IVC filters are divided into procedure related, post-procedure, and retrieval complications. Differences amongst the device types and retrievable filters are described, though this is limited by a significant lack of prospective studies. Additionally, the clinical presentation as well as prevention and treatment strategies are outlined with each complication type.

Use of a Trellis device for endovascular treatment of venous thrombosis involving a duplicated inferior vena cava

Congenital anomalies of the inferior vena cava (IVC) are increasingly recognized with CT and venography techniques. Although many patients with IVC anomalies are asymptomatic, recent studies have suggested an association with venous thromboembolism. We report the case of a 62-year-old woman with extensive venous clot involving the infrarenal segment of a duplicated left IVC who underwent pharmacomechanical thrombectomy and tissue plasminogen activator catheter-directed thrombolysis with complete deep venous thrombosis resolution. To our knowledge this is the first reported case in the English literature of the use of a Trellis thrombectomy catheter in the setting of duplicated IVC.

Optional inferior vena cava filters in the trauma patient

Trauma patients are at exceedingly high risk of development of venous thromboembolism (VTE) including deep venous thrombosis and pulmonary embolism (PE). The epidemiology of VTE in trauma patients is reviewed. PE is thought to be the third major cause of death after trauma in those patients who survive longer than 24 hours after onset of injury. In fact, patients recovering from trauma have the highest rate of VTE among all subgroups of hospitalized patients. Various prophylactic and surveillance methods have been evaluated and found helpful in certain situations, but VTE complications can occur despite such measures. Therapeutic and prophylactic uses of inferior vena cava (IVC) filters in trauma patients are reviewed. Prophylactic IVC filter use is revealed to be a controversial subject with valid arguments on both sides of the issue. With the lack of prospective randomized trials of IVC filter use in trauma, it is impossible to make evidence-based recommendations. Unfortunately, two sets of guidelines are available for insertion of filters in trauma patients, with conflicting recommendations. The introduction of retrievable IVC filters seems to offer a unique solution for VTE protection in the trauma patient population, which often consists of younger members of our population. Lastly, current generations of FDA-approved retrieval filters are discussed.

Filter Placement for Duplicated Cava

Anatomic variations of the inferior vena cava (IVC) are found in 3-5% of the population. IVC duplication is a well-known anatomic variation that is important when relevant procedures are being planed. Therefore, the identification of IVC anomalies should be checked prior to pertinent interventions. We report two cases of dual IVC filter placement for duplicated cava including a missing left inferior vena cava and subsequent pulmonary embolism. The rationale of one versus two filters and the current literature are discussed.

The value of preprocedure computed tomography for planning insertion of inferior vena cava filters

PURPOSE

To determine if valuable information could be obtained from abdominal computed tomography (CT) performed before insertion of an inferior vena cava (IVC) filter.

MATERIALS AND METHODS

A retrospective review was performed on IVC filter insertions with a CT performed before the procedure. Cavagram and CT were compared for renal vein and IVC anatomy, the diameter of the IVC, and the prevalence of iliocaval thrombus. Correlations were assessed among 3 reference standards for measuring the IVC at cavography.

RESULTS

The mean IVC diameter was 23.0 mm on CT. On cavagram the mean IVC diameter was assessed by using 3 reference standards: 20.7 mm, with the catheter tip as a reference; 26.9 mm, with a radiopaque ruler; and 23.4 mm, by using a lumbar vertebral body. There was good correlation among the 3 measures of IVC diameter (Pearson's r = 0.75, P < .0001) but moderate correlation with CT (r = 0.36-0.56, P < .001). The sensitivity of cavagram for detecting retroaortic and circumaortic renal veins was 40% and 0%, respectively. Nineteen accessory renal veins (12.8%) were not seen by cavagram. Thirteen patients (8.8%) had iliocaval thrombus on cavagram, of which 12 (92.3%) were not previously detected by CT.

CONCLUSIONS

CT is more sensitive than cavagram for detection of renal vein variants and the level of the lowest renal vein. Therefore, if available, the CT should be reviewed before placement of an IVC filter to optimize positioning. Cavagram remains the criterion standard for detection of iliocaval thrombosis and is necessary before IVC filter insertion.

Trombectomia com cateter de Fogarty no tratamento da tromboflebite jugular experimental em eqüinos

Trombose da veia jugular é problema freqüente na medicina eqüina, implicando muitas vezes em conseqüências fatais. O objetivo deste trabalho foi avaliar em eqüinos a aplicabilidade da trombectomia com cateter de Fogarty, técnica rotineiramente empregada pela medicina humana, no restabelecimento da perviedade vascular. Foram utilizados 10 eqüinos divididos em dois grupos de cinco animais, em que se induziu a trombose da veia jugular direita, através do acesso cirúrgico à veia e aplicação de sutura estenosante e injeção de glicose a 50%. No grupo controle avaliou-se a evolução da tromboflebite sem qualquer tipo de intervenção terapêutica. Os animais do grupo tratado foram submetidos à trombectomia com cateter de Fogarty. Foram avaliados os parâmetros clínicos gerais, regionais, ultra-sonográficos e angiográficos, nos momentos pré-indução (M-PRÉ), indução da trombose (MTI) e 10 dias de evolução da trombose (M10). A técnica empregada induziu a tromboflebite, que obstruiu completamente um segmento da veia jugular de todos os animais. Os animais do grupo controle mantiveram os trombos obstruindo totalmente o lume vascular até o final do período de avaliação, sendo que avaliações regionais mostraram principalmente o edema parotídeo e o ingurgitamento vascular, cranial à tromboflebite da veia jugular. O grupo tratado apresentou as veias jugulares pérvias ao final do experimento, confirmadas pelos exames ultra-sonográficos e angiográficos, com remissão total dos sinais clínicos. Concluiu-se que a técnica da trombectomia com cateter de Fogarty foi eficiente na desobstrução da veia jugular submetida à trombose experimental.

Vena cava filters: an update

Venous thromboembolism is a major health problem that results in significant long-term complications and mortality. The management of venous thromboembolism is complex and can be particularly challenging when pharmacological therapy alone cannot be effectively utilized. Vena cava filters provide protection from pulmonary embolism for patients in whom therapeutic anticoagulation is contraindicated or inadequate. Recent innovations in caval interruption have included the use of alternative imaging modalities for filter insertion and the emergence of devices designed to allow temporary caval filtration. These developments have been accompanied by a controversial increase in the use of vena cava filters for prophylactic indications in the absence of venous thromboembolism. In addition to a brief historical perspective on caval filtration, this update reviews the indications for vena cava filter insertion, associated complications, methods of caval imaging and filter insertion and current FDA-approved devices.

Vena Cava Filters: Uses and Abuses

Currently, there are more than 10 permanent and optional retrievable vena cava filters in use in North America and Europe. Indications for inferior vena cava (IVC) filter placement are intuitive and filters are used in patients who have deep venous thrombosis (DVT) and contraindications to anticoagulation, or in patients who hemorrhage while anticoagulated for DVT. Multiple studies have proposed broadening the use of IVC filters as primary venous thromboembolism (VTE) prophylaxis in certain patient populations. Many permanent IVC filters have been well studied and have superior performance characteristics. On the other hand, optional retrievable IVC filters are attractive in the patient with a well-defined, short-term risk for VTE and contraindications to anticoagulation. Filter retrieval after the patient can be anticoagulated would eliminate the long-term risk of DVT associated with permanent IVC filter placement. Unfortunately, most optional retrievable filters are relatively new and have little to no data on their long-term performance when used as permanent filters, and the percentage of retrievable filters actually removed is less than 50%. The spirited debate concerning which patient should get which filter is just beginning. More prospective, randomized trials evaluating optional retrievable filters are needed to answer these important questions.

Safety of Contrast Venography prior to Caval Interruption in Patients with Renal Insufficiency

We undertook this study to determine whether the use of contrast venography would adversely affect renal function in patients with renal insufficiency requiring caval interruption. We conducted a retrospective review of all inferior vena cava (IVC) filters inserted at our institution over a 2-year period (January 2002 to January 2004). The indication for caval interruption, insertion technique, type of filter used, pre- and postintervention creatinine level, and the presence of diabetes and hypertension were analyzed. A total of 282 IVC filters were inserted, with 38 of them placed in patients with renal insufficiency as defined by a serum creatinine level of > 1.5 mg/dL. Contrast venography with 15 to 30 mL of iohexol (Omnipaque 300) was used in all cases, and no special measures other than proper hydration were used for renal protection. All filters were successfully deployed. The mean +/- SD preintervention creatinine level was 2.38 +/- 0.79 mg/dL. The mean +/- SD postintervention creatinine levels at 2 and 30 days were 2.26 +/- 0.45 mg/dL and 2.12 +/- 0.94 mg/dL, respectively. No patients required hemodialysis following caval interruption, and no adverse effect on renal function was noted. Contrast venography accurately delineates venous anatomy and facilitates proper caval filter placement with no apparent adverse effect on renal function. We believe contrast venography is safe even in the presence of renal insufficiency.

Comparison of Bedside Transabdominal Duplex Ultrasound versus Contrast Venography for Inferior Vena Cava Filter Placement: What Is the Best Imaging Modality?

While contrast venography is considered the gold standard for imaging prior to inferior vena cava (IVC) filter insertion, bedside placement via transabdominal duplex ultrasound (DUS) has been recognized as a safe and effective alternative. To date, there has been no direct comparison of the efficacy of both imaging modalities for IVC filter placement. A concurrent cohort of patients who underwent IVC filter placement at a single institution over a 7-year period with either contrast venography or transabdominal DUS performed at bedside was retrospectively reviewed. Patient demographics, venous thromboembolism risk factors, indications, technical success, and procedural complications were compared. Of 439 patients initially imaged with transabdominal DUS, IVC filter placement was determined to be technically feasible in 382 patients (87%). The procedural technical success rate for IVC filter placement using transabdominal DUS when IVC visualization was adequate was 97.4% (n = 382 patients), compared to 99.7% (n = 318 patients) for contrast venography (p = 0.018). Patients undergoing IVC filter placement with transabdominal DUS more commonly required IVC filter for venous thromboembolism prophylaxis (81.1% vs. 27.8%, p < 0.001), had increased incidence of multiple traumatic injuries (28% vs. 10%, p < 0.001), and had increased risk from immobilization (91.3% vs. 34.1%, p < 0.001). Overall complication rates were 0.6% for venography and 1.8% for transabdominal DUS (p = NS). When IVC visualization was adequate, contrast venography and transabdominal duplex ultrasound both had high rates of success and a low incidence of complications. A technical success advantage was observed for contrast venography; this difference in technical success must be weighed against the bedside insertion advantage offered by DUS, which may be especially important in the immobilized or critically ill patient. Transabdominal DUS remains our preferred technique when feasible, especially when bedside placement is desired.