What management and workup are recommended for a patient with pulmonary embolism (PE) and a non-occlusive thrombus within the right common iliac artery extending to the infrarenal inferior vena cava (IVC), beyond initial heparin (unfractionated heparin) therapy?

Management of PE with Non-occlusive Thrombus in Right Common Iliac Artery Extending to Infrarenal IVC

Beyond heparin infusion, this patient requires urgent consultation with a multidisciplinary PE response team, consideration for IVC filter placement, and comprehensive thrombophilia workup.

Immediate Management

1. Continue Unfractionated Heparin (UFH) Infusion

   • Maintain therapeutic aPTT of 1.5-2.5 times control 1
   • UFH is preferred over LMWH in this case due to:
     • Extensive clot burden involving both pulmonary and systemic circulation
     • Potential need for rapid reversal if intervention becomes necessary 2, 1

2. Urgent Consultation with PE Response Team (PERT)

   • This complex case with both PE and iliocaval thrombosis warrants multidisciplinary evaluation 2
   • The team should include specialists from cardiology, vascular surgery, interventional radiology, and hematology

3. Consider IVC Filter Placement

   • Given the presence of thrombus in the IVC and iliac artery, an IVC filter should be considered to prevent further PE 2
   • This is particularly important as the patient has a large clot burden that could lead to massive PE if it embolizes 2

Additional Workup

1. Assess Hemodynamic Status

   • Echocardiography to evaluate right ventricular function
   • Continuous monitoring of vital signs and oxygen saturation
   • Consider ICU admission if any signs of hemodynamic instability 2

2. Thrombophilia Workup

   • Complete blood count with platelet monitoring
   • Coagulation profile (PT/INR, aPTT)
   • D-dimer levels
   • Antiphospholipid antibodies
   • Factor V Leiden, Prothrombin gene mutation
   • Protein C, Protein S, and Antithrombin III levels
   • Homocysteine levels 2, 1

3. Cancer Screening

   • Comprehensive history and physical examination
   • Age-appropriate cancer screening
   • Chest/abdomen/pelvis CT (if not already performed)
   • Consider tumor markers if clinically indicated 2, 1

Transition to Long-term Anticoagulation

1. Transition to Oral Anticoagulation

   • After at least 5 days of heparin therapy and when clinically stable
   • Direct oral anticoagulants (DOACs) are preferred over vitamin K antagonists for most patients 2
   • Options include:
     • Apixaban: 10 mg BID for 7 days, then 5 mg BID
     • Rivaroxaban: 15 mg BID for 21 days, then 20 mg daily 1

2. Avoid DOACs if:

   • Severe renal impairment (CrCl <30 mL/min)
   • Antiphospholipid antibody syndrome
   • Pregnancy or breastfeeding 2

3. If VKA is chosen:

   • Target INR of 2.0-3.0
   • Continue heparin until INR is therapeutic for at least 2 consecutive days 2, 3

Duration of Anticoagulation

1. Extended anticoagulation (>3 months) is recommended due to:

   • Extensive clot burden
   • Involvement of both pulmonary and systemic circulation
   • Unprovoked nature (unless a clear transient risk factor is identified) 2, 1

2. Reassess at 3-6 months:

   • Evaluate for resolution of thrombi
   • Screen for chronic thromboembolic pulmonary hypertension
   • Reassess risk-benefit ratio of continued anticoagulation 1

Follow-up

1. Short-term (1-2 weeks):

   • Monitor anticoagulation efficacy and safety
   • Repeat imaging to assess thrombus evolution

2. Medium-term (3-6 months):

   • Evaluate for chronic thromboembolic pulmonary hypertension
   • Complete thrombophilia workup if initial results are pending
   • Assess for underlying causes if not previously identified 1

3. Long-term:

   • Regular reassessment of anticoagulation need and bleeding risk
   • Annual imaging if on indefinite anticoagulation

Common Pitfalls to Avoid

1. Delaying IVC filter consideration in patients with iliocaval thrombosis and PE
2. Inadequate thrombophilia workup in patients with extensive, unprovoked thrombosis
3. Premature discontinuation of anticoagulation in patients with extensive clot burden
4. Failure to consult multidisciplinary team for complex VTE cases 2, 1