Bedside Placement of a Retrievable Inferior Vena Cava Filter in a Morbidly Obese Patient Guided by Modified IVUS Approach

ABSTRACT: Deep vein thrombosis and pulmonary embolism are major causes of morbidity and mortality in trauma patients. Anticoagulation therapy is often contraindicated in these patient populations. The retrievable inferior vena cava (IVC) filter provides a good option for preventing pulmonary embolism in the immediate injury and postoperative periods. Bedside IVC filter placement by guidance of intravascular ultrasound eliminates the risk of transportation; it is safe, efficient, and cost effective. We hereby present a case of bedside IVC filter placement in a morbidly obese patient with modified intravascular ultrasound approach.

J INVASIVE CARDIOL  2012;24(12):E311-E313

Key words: inferior vena cava filter, IVC filter, IVUS, morbidly obese

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Deep venous thrombosis (DVT) and pulmonary embolism (PE) are major causes of morbidity and mortality in trauma patients. In this patient population, use of anticoagulation therapy is often contraindicated. Temporary inferior vena cava (IVC) filters provide a good option of preventing PE during the early immediate injury and perioperative periods, and avoid long-term adverse effect of permanent placement of IVC filters. IVC filter placement with contrast-enhanced venography is the standard deployment technique. However, risks include difficulty during transportation from the intensive care unit bed to the operating room or catheterization lab, contrast, and radiation exposure. Transportation of patients to the imaging suite may not be feasible or recommended due to patient’s morbid obesity, hemodynamic or neurologic instability, respiratory failure, open abdomen, risk of dislodgment of invasive monitors, and intracerebral pressure monitors. Alternatively, IVC filters can be placed at bedside while guided by intravascular ultrasound (IVUS), which has been shown to be safe, practical, and cost effective. We hereby present the case of a morbidly obese trauma patient with bedside retrievable IVC filter placement using a modified IVUS technique.

Case Presentation. A 34-year-old morbidly obese (517 lb) male presented to our university hospital after sustaining multiple injuries from an all-terrain vehicle accident. Radiographic studies showed right hemipelvis disruption with complete closed right sacroiliac joint dislocation, complete pubic symphyseal disruption, and left acetabular fractures. Orthopedic surgeon performed open reduction and internal fixation of right sacroiliac joint and open management with internal fixation of pubic symphyseal/anterior pelvis disruption. PE and/or DVT risk was considered to be remarkably high during the postoperative period in this patient, considering pelvic surgery with a prolonged bed rest, immobility and morbid obesity. Anticoagulation therapy as a mode of DVT/PE prophylaxis was relatively contraindicated. Therefore, it was deemed necessary to place an IVC filter for PE prophylaxis. Operating room or catheterization laboratory tables available were not able to accommodate the patient because of table weight limits. Therefore, bedside retrievable IVC filter guided by IVUS was placed on postoperative day 2. It was successfully removed on postoperative day 15.

Technique

Deployment. The nitinol magnetic resonance imaging-compatible OptEase filter (Figure 1) has a unique self-centering design that provides dual-level filtration, and is the only filter that is retrievable via femoral vein approach. Under aseptic conditions, one femoral vein puncture was made, and a 0.035˝ Magic Torque guidewire (Boston Scientific) was introduced into the vena cava. An 8 Fr sheath was introduced over the wire. A 10 MHz IVUS probe (Boston Scientific) was passed to the level of the right atrium. Venous anatomy was interrogated with a pullback technique that enabled easy identification of the liver, hepatic veins, renal artery, and renal veins. The transverse IVC diameter was measured in 2 planes at the infrarenal location to ensure that maximum size of the IVC diameter did not exceed 28 mm. Markers were placed proximally in the IVUS catheter at the site of entry into the sheath in two places; one when the more inferior renal vein was identified and one at the site of the IVC bifurcation into the iliac veins. With a sterile measuring tape, the distance in centimeters from the sheath hub to the ideal place of deployment between the more distal renal vein and IVC bifurcation was determined. The IVC filter sheath was introduced at the ideal distance and then deployed. The introducer, IVUS probe, and sheaths were removed after deployment of the IVC filter. Gentle pressure was applied until hemostasis was achieved. Anteroposterior abdominal x-ray films were obtained to evaluate the IVC filter location. 

Retrieval. Our patient underwent venous color-flow duplex ultrasound scanning of the lower extremities to rule out lower extremity DVT before filter retrieval. IVC filter retrieval was performed in the catheterization laboratory under aseptic conditions via right femoral vein approach as the patient’s weight had decreased to 498 lb and was within table weight limits. A 12 Fr sheath was placed, and a pigtail catheter (Cordis Corporation) was used for imaging (Figure 2). Vena cavography was performed before retrieval, which did not reveal any trapped emboli or thrombi within the IVC filter. Repeat vena cavography was performed after retrieval of the filter with a snare to evaluate IVC patency.

Discussion. PE and/or DVT still remain momentous causes of mortality and morbidity in trauma patients. Obesity puts these patient populations at even higher risk. Often, these patients require IVC filter placement to reduce the risk of PE in the early postoperative period. IVC filter placement with contrast-enhanced venography remains the standard deployment technique. However, it brings the risks associated with transportation, contrast-induced nephropathy, and radiation exposure. Carbon dioxide bedside fluoroscopy has been used for bedside IVC filter placement, but it requires a portable fluoroscopy unit capable of performing venography. In our patient, this option was not feasible due to likelihood of limited visualization on the Hill-Rom bed due to orthopedic devices and morbid obesity. Bedside IVC filter placement with guidance of transabdominal duplex ultrasound or IVUS are other options and not associated with the above-mentioned risks.^1-6 However, transabdominal duplex ultrasound-guided IVC filter placement can be limited by poor visibility of the IVC due to obesity, abdominal wound, and bowel gas.^4,7,8 

Unavailability of the catheterization table, which could accommodate our patient, led us to choose bedside IVC filter via IVUS. There are two techniques available for bedside IVC filter placement via IVUS: single-puncture access or double-puncture access. Double-puncture technique has an advantage of continuous real-time ultrasound scanning of the IVC and renal veins to ensure precise filter placement. However, concern of femoral vein thrombosis is high if the ipsilateral common femoral vein is used for double-puncture access. In our patient, extreme difficulty achieving common femoral vein access led us to use single-puncture access. The need for a larger sheath for an IVUS probe technically limits filter choices for single access to filter-delivery systems with at least an 8 Fr sheath. Other complications associated with both of these techniques are similar to IVC filter placement by contrast-enhanced venography, which includes malposition of filter (suprarenal portion of IVC or common iliac vein), caval thrombosis, IVC wall penetration by filter struts, filter migration to remote locations, filter strut fracture, and femoral arteriovenous fistula.^3,9-12 A major concern associated with using IVUS for IVC filter placement is missing venous anomalies, which can be addressed by obtaining computed tomography scan. 

Besides the above-mentioned benefits, this technique is cost effective. In 1997, Nunn et al noted the adjusted annualized savings for bedside IVC filter placement of approximately $69,000 and $118,000 compared to radiology suite and operating room costs, respectively.⁷ However, Rosenthal et al showed in their study that hospital charge were $5783, $4744, and $4920 per patient for IVC placement in the operating room, radiology suite, and intensive care unit bedside, respectively.¹³ The relatively higher cost with bedside insertion was due to cost of the IVUS probe ($600).¹³

In conclusion, IVC filter placement with IVUS guidance at bedside is safe, effective, accurate, and cost effective. Although IVC filter placement is performed by vascular surgeons and interventional radiologists, this procedure can be safely performed by interventional cardiologists considering our familiarity with IVUS due to frequent uses of it in other procedures. To our knowledge, this is the first reported case in the medical literature of bedside IVC filter placement in a patient >500 lb with IVUS guidance by modified single-puncture technique. 

References

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