What is the standard of care for a pregnant patient with vaginal bleeding and suspected pulmonary embolism (PE)?

Management of Pregnant Patients with Vaginal Bleeding and Suspected Pulmonary Embolism

For pregnant patients with vaginal bleeding and suspected pulmonary embolism (PE), the standard of care requires immediate diagnostic evaluation with imaging studies while considering anticoagulation therapy, with the specific imaging approach determined by chest X-ray findings.

Initial Assessment and Stabilization

• Assess hemodynamic stability immediately
• If hemodynamically unstable, perform bedside transthoracic echocardiography to assess for right ventricular dysfunction 1, 2
• Evidence of acute RV dysfunction in an unstable patient is sufficient to prompt immediate reperfusion therapy without further testing 2
• Institute anticoagulation therapy as soon as possible while diagnostic workup is ongoing, unless the patient has active bleeding or absolute contraindications 1

Diagnostic Algorithm

Step 1: Basic Diagnostic Tests

• Perform chest X-ray (CXR) as the first radiation-associated procedure 1
• Assess for DVT symptoms, particularly in the left leg (more common in pregnancy) 2
• Consider D-dimer testing, though its utility is limited in pregnancy 1

Step 2: Imaging Selection Based on CXR Results

• If CXR is normal:

  • Perform lung scintigraphy (V/Q scan) as the next imaging test rather than CTPA 1
  • Use dose reduction techniques for V/Q scan: half the usual administered activity of Tc-99m macroaggregated albumin and increase scan time 1, 2

• If CXR is abnormal:

  • Perform CTPA with a low-radiation dose protocol 1
  • Use pregnancy-specific CTPA protocols with automated bolus triggering, high iodine flux, and clear breathing instructions 1

Step 3: Additional Testing When Needed

• If the patient has signs/symptoms of DVT:

  • Perform bilateral compression ultrasonography (CUS) of lower extremities 1
  • If CUS is positive, begin anticoagulation treatment
  • If CUS is negative, proceed with pulmonary vascular imaging 1

• If V/Q scan is nondiagnostic:

  • Proceed to CTPA rather than digital subtraction angiography 1

Treatment Approach

Anticoagulation

• Low molecular weight heparin (LMWH) is the preferred anticoagulant during pregnancy 2
• Unfractionated heparin (UFH) is typically used in high-risk PE, especially peri-partum 1
• Avoid NOACs (non-vitamin K antagonist oral anticoagulants) during pregnancy 1

For High-Risk PE

• Consider thrombolysis or surgical embolectomy for pregnant women with high-risk PE 1
• Thrombolysis should not be used peri-partum except in life-threatening PE 1
• Major bleeding risk following thrombolysis: 18% during pregnancy and 58% in post-partum period 1

Special Considerations for Vaginal Bleeding

• The presence of vaginal bleeding requires careful assessment of the bleeding severity and potential contraindications to anticoagulation
• For minor vaginal bleeding with high clinical suspicion of PE, anticoagulation may still be initiated while expediting diagnostic workup
• For significant vaginal bleeding, consider:
  • Expedited diagnostic testing to confirm or exclude PE
  • Temporary use of inferior vena cava filter if anticoagulation is absolutely contraindicated
  • Consultation with maternal-fetal medicine and hematology specialists

Multidisciplinary Approach

• Involve a multidisciplinary pregnancy heart team including specialists in maternal-fetal medicine, cardiology, hematology, and emergency medicine 1, 2
• Develop jointly agreed, written care pathways for effective communication 1
• Consider specialized interventions for massive or submassive PE with a multidisciplinary approach 2

Key Pitfalls to Avoid

• Delaying diagnostic workup due to concerns about radiation exposure
• Failing to use pregnancy-specific protocols for imaging studies
• Overlooking left-sided DVT, which is more common in pregnancy
• Misinterpreting normal pregnancy symptoms as signs of PE
• Delaying anticoagulation when clinical suspicion is high and bleeding risk is low

Remember that PE is a leading cause of pregnancy-related maternal death in developed countries, accounting for approximately 20% of maternal deaths in the United States 2. A high index of suspicion and prompt, appropriate management are essential to reduce morbidity and mortality.