A 58-year-old woman presents to the emergency department with acute onset dyspnea and pleuritic chest pain for 6 hours. She underwent total abdominal hysterectomy 4 days ago. On examination: BP 128/82 mmHg, HR 112/min, RR 24/min, SpO₂ 94% on room air. Unilateral leg swelling is noted. D-dimer is elevated at 2.8 μg/mL. CT pulmonary angiography (CTPA) shows a segmental pulmonary artery occlusion in the right lower lobe. What is the most appropriate immediate management?

Explanation

## Diagnosis and Risk Stratification **Key Point:** This patient has confirmed acute pulmonary embolism (PE) with hemodynamic stability (BP normal, no shock) and no contraindications to anticoagulation — she is at intermediate or low risk. **High-Yield:** Segmental PE with normal vital signs and oxygenation is NOT a massive PE and does NOT require thrombolysis. ## Management Algorithm for Acute PE ```mermaid flowchart TD A[Confirmed PE on CTPA]:::outcome --> B{Hemodynamically stable?}:::decision B -->|No - Shock/RV dysfunction| C[Thrombolysis or embolectomy]:::urgent B -->|Yes - Stable| D{Contraindications to anticoagulation?}:::decision D -->|Yes| E[IVC filter]:::action D -->|No| F[Anticoagulation: UFH or LMWH]:::action F --> G[Transition to warfarin/DOAC]:::action G --> H[Long-term anticoagulation]:::outcome ``` ## Anticoagulation in Acute PE | Agent | Indication | Timing | Monitoring | |-------|-----------|--------|------------| | **Unfractionated heparin (UFH)** | Confirmed PE, normal renal function, may need urgent reversal | Bolus 80 U/kg IV, then infusion | aPTT target 1.5–2.5× baseline | | **Low-molecular-weight heparin (LMWH)** | Confirmed PE, outpatient-eligible, renal function >30 mL/min | Weight-based SC injection | No monitoring required | | **Warfarin** | Long-term anticoagulation (NOT first-line for acute PE) | Started after heparin overlap (5–7 days) | INR target 2–3 | | **Direct oral anticoagulants (DOACs)** | Alternative after initial parenteral anticoagulation | After 5–10 days of heparin | No monitoring | **Clinical Pearl:** UFH is preferred in this case because: 1. Immediate anticoagulation is needed (UFH has rapid onset). 2. She is post-surgical (may need urgent reversal with protamine if bleeding occurs). 3. UFH allows flexibility if IVC filter or thrombolysis becomes necessary. **Warning:** Starting warfarin alone without heparin overlap is dangerous — warfarin initially depletes protein C (a natural anticoagulant), paradoxically increasing thrombotic risk for 24–48 hours. Always overlap heparin and warfarin for ≥5 days. ## Why Thrombolysis Is NOT Indicated **Key Point:** Thrombolysis is reserved for **massive PE** (hemodynamic instability, cardiogenic shock, RV dysfunction on echo/RV:LV ratio >0.9 on CT) or **submassive PE with RV dysfunction and elevated troponin**. This patient has: - Normal blood pressure (not hypotensive) - Acceptable oxygenation (SpO₂ 94%) - Segmental (not lobar/massive) PE - No mention of shock or RV strain Thrombolysis carries significant bleeding risk and is not justified.