Overview
Definition:
Inferior vena cava (IVC) filters are devices placed in the IVC to prevent pulmonary embolism (PE) in patients who cannot tolerate anticoagulation
Peri-operative management encompasses the care provided before, during, and immediately after filter placement to optimize outcomes and minimize complications.
Epidemiology:
PE is a significant cause of morbidity and mortality
IVC filters are indicated in a subset of patients with deep vein thrombosis (DVT) or PE at high risk for recurrence and contraindication or failure of anticoagulation
Incidence varies based on criteria and patient populations, with increasing utilization noted globally.
Clinical Significance:
Effective peri-operative management is crucial for successful IVC filter placement, aiming to prevent life-threatening PE while mitigating procedural risks
It involves careful patient selection, meticulous technique, and vigilant post-procedural monitoring
Proper management ensures the filter achieves its intended prophylactic role and facilitates safe removal when no longer indicated.
Indications And Contraindications
Indications:
Absolute indications include confirmed DVT or PE with documented contraindication to anticoagulation (e.g., active bleeding, recent surgery, hemorrhagic stroke)
failure or recurrence of PE despite adequate anticoagulation
Relative indications include massive PE with hemodynamic instability
pulmonary hypertension secondary to chronic thromboembolic disease
and prophylaxis in high-risk trauma patients.
Contraindications:
Absolute contraindications include an IVC that is too small to accommodate the filter, severe coagulopathy that cannot be corrected, and absence of DVT or PE in a patient with a bleeding risk
Relative contraindications may include caval anomalies, extensive thrombotic burden precluding safe passage of the filter, or concurrent systemic infection.
Patient Selection Criteria:
Careful assessment of the risk of PE versus the risk of anticoagulation is paramount
Guidelines from societies like the Society of Interventional Radiology (SIR) provide a framework for appropriate patient selection
The presence of proximal DVT or PE and the patient's ability to tolerate anticoagulation are key determinants.
Preoperative Preparation
Medical Evaluation:
Thorough review of patient history, including bleeding disorders, anticoagulant use, renal function (contrast administration), allergies, and comorbidities
Assessment of cardiovascular and respiratory status
Confirmation of IVC anatomy via imaging.
Imaging Studies:
Venography (ilio-femoral) to delineate thrombus burden and IVC diameter
CT or MRI may be used to assess IVC anatomy and rule out caval anomalies or existing thrombus extending into the suprarenal IVC.
Laboratory Tests:
Complete blood count (CBC), coagulation profile (PT/INR, aPTT), renal function tests (creatinine, BUN)
Type and screen for potential blood transfusion
Pregnancy test for women of childbearing potential.
Anticoagulation Management:
If the patient is on anticoagulation, strategies for peri-procedural management (e.g., bridging with heparin, holding specific agents) are determined based on the indication for filter placement and the procedural risk
For patients with contraindication, this aspect is less critical but still requires assessment of potential for future anticoagulation.
Informed Consent:
Detailed discussion with the patient and family about the procedure, its benefits, risks (e.g., filter migration, fracture, caval perforation, recurrent thrombosis, post-filter syndrome), alternatives, and expected outcomes
Documentation of informed consent.
Perioperative Management During Procedure
Anesthesia And Sedation:
Typically performed under local anesthesia with conscious sedation
General anesthesia may be required for agitated patients or those undergoing concurrent procedures.
Access Site Preparation:
Usually achieved via percutaneous access of the common femoral vein
Site is prepped and draped sterilely
Ultrasound guidance for venous access can improve success rates and reduce complications.
Procedural Technique:
Guidewire and sheath insertion into the IVC
Accurate filter deployment is critical, typically aiming for infrarenal placement
Imaging (fluoroscopy, venography) is used to confirm appropriate position and filter deployment
Caval venography post-deployment helps assess for thrombus burden and filter patency.
Anticoagulation During Procedure:
Intravenous heparin is often administered during the procedure to maintain anticoagulation and reduce thrombotic complications
Dosing is adjusted based on activated clotting time (ACT) if measured.
Monitoring:
Continuous hemodynamic and oxygen saturation monitoring
Close observation for any signs of adverse reaction to anesthesia, contrast media, or procedural complications.
Postoperative Care And Monitoring
Immediate Postoperative Care:
Bed rest for a specified period (e.g., 4-6 hours) to minimize risk of bleeding at the access site
Vital sign monitoring
Assessment of pain and administration of analgesics
Monitoring for signs of bleeding or hematoma at the access site.
Imaging And Follow Up:
Post-procedure imaging (e.g., duplex ultrasound) of the access site to rule out pseudoaneurysm or deep vein thrombosis
Serial imaging may be performed to assess filter position and patency, and to monitor for recurrent DVT/PE
Long-term follow-up is essential for timely filter retrieval.
Anticoagulation Strategy:
The decision regarding resumption or initiation of anticoagulation post-filter placement is individualized
It depends on the initial indication for filter placement, the presence of residual thrombus, and the patient's bleeding risk
Often, anticoagulation is resumed once bleeding risk has subsided.
Potential Complications Monitoring:
Vigilance for signs of filter migration, embolization, caval perforation, tilting, or obstruction
Monitoring for symptoms suggestive of post-filter syndrome (e.g., lower extremity edema, venous claudication).
Filter Retrieval Considerations:
IVC filters are generally intended for temporary use
A plan for retrieval should be established at the time of placement
Retrieval is typically considered once the risk of PE has diminished and anticoagulation can be safely managed
Delayed retrieval increases the risk of complications.
Complications Of Ivc Filter Placement
Early Complications:
Access site complications (hematoma, bleeding, pseudoaneurysm)
Arrhythmias during manipulation
Allergic reaction to contrast
Caval injury (perforation, dissection)
Filter embolization or migration
Acute IVC thrombosis.
Late Complications:
Post-filter syndrome (chronic venous insufficiency, leg swelling, venous claudication)
Filter fracture or detachment
Recurrent DVT or PE despite filter
Late caval occlusion
Erosion through the caval wall.
Prevention And Management:
Meticulous technique, appropriate patient selection, and judicious use of anticoagulation can mitigate risks
Management of complications depends on the specific event
for example, filter embolization may require surgical or interventional retrieval, while post-filter syndrome may require conservative management and compression therapy.
Key Points
Exam Focus:
Indications for IVC filter placement are crucial
Understand the difference between temporary and permanent filters
Peri-operative management aims to optimize safety and efficacy
Complications like migration, fracture, and post-filter syndrome are high-yield.
Clinical Pearls:
Always document IVC filter placement and retrieval status in patient records
Utilize imaging to confirm correct filter position and rule out complications
Consider filter retrieval once the risk of PE has passed and anticoagulation is safe
Ultrasound guidance for access improves outcomes.
Common Mistakes:
Inappropriate patient selection, failure to perform adequate pre-procedural imaging, incorrect filter deployment leading to suboptimal position, inadequate post-operative monitoring, and failure to plan for filter retrieval.