Cardiovascular · Year 1 · from Cardiovascular

Case 3: Deep Vein Thrombosis and Pulmonary Embolism - Virchow's Triad

Clinical Image

Source: Wikimedia Commons - DVT - CC BY-SA 3.0

Patient Presentation

A 45-year-old woman presents to the emergency department with 3 days of left leg swelling and pain. Yesterday she developed shortness of breath with exertion. She returned from a 12-hour flight from Australia 5 days ago. She also mentions she was started on hormone replacement therapy 3 months ago for menopausal symptoms.

Demographics

  • Age: 45 years
  • Sex: Female
  • Past Medical History: Surgical menopause (hysterectomy 6 months ago for fibroids)
  • Medications: Estrogen replacement therapy
  • Social History: Occasional alcohol, no smoking

Chief Complaint

Left leg swelling and pain for 3 days, shortness of breath for 1 day

Physical Examination

  • Blood pressure: 118/76 mmHg
  • Heart rate: 105 bpm
  • Respiratory rate: 22/min
  • Oxygen saturation: 92% on room air
  • Left lower extremity:
  • Circumferential swelling (3 cm larger than right at mid-calf)
  • Warmth and erythema
  • Tenderness along the medial thigh
  • Positive Homan's sign (nonspecific)
  • Pitting edema
  • Cardiovascular: Tachycardic, regular rhythm
  • Respiratory: Clear to auscultation, mild tachypnea

Workup

  • Wells Score for DVT: 4 (moderate-high probability)
  • Wells Score for PE: 4.5 (moderate probability)
  • D-dimer: 3,450 ng/mL (elevated)
  • Compression ultrasound: Non-compressible left common femoral and popliteal veins with echogenic thrombus
  • CT pulmonary angiography: Bilateral segmental pulmonary emboli; no RV strain
  • Troponin: Mildly elevated
  • BNP: 180 pg/mL (mildly elevated)
  • Echocardiography: Normal RV size and function

Diagnosis

Proximal Deep Vein Thrombosis with Submassive (Intermediate-Low Risk) Pulmonary Embolism

Treatment

  1. Anticoagulation initiated immediately:
  • Options: LMWH bridge to warfarin, or DOAC monotherapy (rivaroxaban or apixaban)
  1. Duration: Minimum 3 months; extended duration consideration given provoked by modifiable factors
  2. Discontinue estrogen therapy (major risk factor)
  3. Risk stratification: Intermediate-low risk PE (positive biomarkers but no RV dysfunction) - does not require thrombolysis
  4. Graduated compression stockings for DVT symptoms
  5. Early ambulation (bed rest not required)
  6. Outpatient follow-up; consider IVC filter only if anticoagulation contraindicated

Physiological Principles Demonstrated

  • Virchow's triad: This patient demonstrates all three components:
  • Stasis: Prolonged immobility during long-haul flight
  • Endothelial injury: Recent surgery (hysterectomy)
  • Hypercoagulability: Exogenous estrogen therapy
  • DVT and PE connection: Over 90% of pulmonary emboli originate from lower extremity or pelvic DVT, emphasizing that DVT and PE are the same disease process.
  • Risk stratification: Not all PEs require aggressive intervention. Hemodynamic stability and RV function determine management intensity.
  • Provoked vs. unprovoked: This VTE is provoked by identifiable transient risk factors (travel, estrogen), informing duration of anticoagulation and recurrence risk.

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