What is the treatment for a patient with a suspected pulmonary embolism?

Treatment of Suspected Pulmonary Embolism

Start immediate anticoagulation with weight-adjusted intravenous heparin (80 IU/kg bolus followed by 18 IU/kg/hour infusion) as soon as PE is suspected based on clinical probability, even before diagnostic confirmation, unless active bleeding or absolute contraindications exist. 1, 2, 3

Initial Assessment and Risk Stratification

When PE is suspected, immediately assess hemodynamic stability to determine treatment intensity 3:

• High-risk PE: Systemic hypotension (SBP <90 mmHg), cardiogenic shock, or sudden collapse with elevated jugular venous pressure 4, 3
• Hemodynamically stable PE: All other presentations 1

Recognize classic presentations 1:

• Sudden collapse with elevated JVP (faintness/hypotension)
• Pulmonary hemorrhage syndrome (pleuritic pain/hemoptysis)
• Isolated dyspnea without cough, sputum, or chest pain

Critical pitfall: PE is easily missed in elderly patients, those with severe cardiorespiratory disease, and when isolated dyspnea is the only symptom 4. Most PE patients are breathless and/or tachypneic (respiratory rate >20/min) 4, 1.

Immediate Anticoagulation Management

For Hemodynamically Stable Patients

Initiate weight-adjusted IV heparin immediately 1, 2:

• Initial bolus: 80 IU/kg IV 4
• Maintenance infusion: 18 IU/kg/hour 4
• Target aPTT: 1.5-2.5 times control (45-75 seconds) 4, 1

aPTT monitoring schedule 4:

• First check: 4-6 hours after initial bolus
• After any dose change: 6-10 hours later
• Once therapeutic: Daily monitoring

Transition to oral anticoagulation 4:

• Start warfarin 5-10 mg daily for 2 days, then adjust to INR 2.0-3.0 4
• Discontinue heparin after 5 days if INR ≥2.0 4
• Measure INR every 1-2 days initially 4

Alternative: Direct oral anticoagulants (DOACs) are preferred over traditional LMWH-warfarin regimen unless contraindications exist 3. Rivaroxaban and apixaban are FDA-approved for PE treatment 5, 6, 5.

For Hemodynamically Unstable Patients (High-Risk PE)

Systemic thrombolysis is indicated for patients with systemic hypotension or cardiogenic shock 1, 3.

Thrombolytic regimens 4:

• rtPA: 100 mg IV over 2 hours
• Streptokinase: 250,000 units IV over 20 minutes, then 100,000 units/hour for 24 hours (plus hydrocortisone to prevent circulatory instability)
• Urokinase: 4,400 IU/kg IV over 10 minutes, then 4,400 IU/kg/hour for 12 hours

Before thrombolysis: Stop heparin; after thrombolysis: Resume maintenance dose heparin 4

If thrombolysis contraindicated or fails: Consider surgical embolectomy if no clinical improvement within one hour 3

Duration of Anticoagulation

Minimum 3 months anticoagulation for all confirmed PE 1, 3, 7:

• Discontinue after 3 months: First episode with strong transient/reversible risk factor (recent surgery, immobilization, trauma) 4, 3
• Continue indefinitely: Unprovoked PE, recurrent VTE, or active cancer 1, 3, 7

Re-examine patient after initial 3-6 months to weigh benefits versus bleeding risks for extended anticoagulation 3

Special Populations

Active cancer patients: Low molecular weight heparin (LMWH) is superior to DOACs and should be continued indefinitely while cancer is active 3

Unprovoked or recurrent PE: Test for antiphospholipid antibodies 3. If triple-positive antiphospholipid syndrome, DOACs are contraindicated—use warfarin (INR 2.0-3.0) instead 3

Renal failure patients: Unfractionated heparin is preferred over LMWH 8

IVC Filter Placement

Place IVC filter only in patients with absolute contraindication to anticoagulation or recurrent PE despite adequate anticoagulation 3. This is not routine therapy.

Discharge Criteria and Follow-Up

Before discharge, ensure 4:

• INR between 2.0-3.0
• Patient educated on anticoagulant side effects and drug/food interactions
• Written warfarin information provided
• Anticoagulant supervision appointment scheduled
• General practitioner informed of diagnosis and treatment duration

Follow-up schedule 3:

• Initial follow-up: 1-2 weeks post-discharge
• Comprehensive assessment: 6-12 weeks
• Yearly examinations for patients on extended anticoagulation

At every visit, ask about persistent or new-onset dyspnea or functional limitation 3. If symptomatic after 3 months, implement staged diagnostic workup to exclude chronic thromboembolic pulmonary hypertension (CTEPH) 3.