What is the management approach for a patient with acute pulmonary thromboembolism?

Management of Acute Pulmonary Thromboembolism

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

Immediate Assessment and Risk Stratification

High-Risk (Massive) PE:

• Identify by presence of systemic hypotension (systolic BP <90 mmHg), cardiogenic shock, or sudden collapse with engorged neck veins and right ventricular gallop 2, 1
• Perform bedside transthoracic echocardiography immediately in hemodynamically unstable patients to differentiate PE from other acute life-threatening conditions 1
• Administer 50 mg alteplase IV immediately in deteriorating patients or those in cardiac arrest 2
• If thrombolysis is contraindicated or fails to produce clinical improvement within one hour, consider surgical pulmonary embolectomy 2, 1

Stable Patients:

• Most PE patients present with breathlessness and/or tachypnea (respiratory rate >20/min) 1
• Begin anticoagulation immediately while awaiting diagnostic confirmation 2, 1

Initial Anticoagulation Regimen

Preferred approach: Weight-adjusted unfractionated heparin 2, 1

• Bolus: 80 IU/kg IV 2, 1
• Continuous infusion: 18 IU/kg/hour 2, 1
• Target aPTT: 1.5-2.5 times control (45-75 seconds) 2, 1
• Check aPTT 4-6 hours after initial bolus, then 6-10 hours after any dose change, then daily once therapeutic 2

Dose adjustments based on aPTT: 2

• aPTT <35 seconds (<1.2 times control): 80 IU/kg bolus; increase infusion by 4 IU/kg/hour
• aPTT 35-45 seconds (1.2-1.5 times control): 40 IU/kg bolus; increase infusion by 2 IU/kg/hour
• aPTT 46-70 seconds (1.5-2.3 times control): No change
• aPTT 71-90 seconds (2.3-3.0 times control): Reduce infusion rate

Alternative: Low-molecular-weight heparin (LMWH) 3, 4

• Enoxaparin 1 mg/kg subcutaneously twice daily 3, 4
• No monitoring required 3
• Equally effective and safe as unfractionated heparin for non-massive PE 3

Critical caveat: Do NOT initiate rivaroxaban or other NOACs acutely in hemodynamically unstable patients or those who may require thrombolysis or pulmonary embolectomy—use unfractionated heparin instead 5

Thrombolytic Therapy

Indications: 2, 1

• Hemodynamic instability with systemic hypotension
• Cardiogenic shock
• Cardiac arrest due to PE

Regimen: 2

• Alteplase (rtPA): 100 mg IV over 90 minutes for stable confirmed massive PE, or 50 mg IV bolus for deteriorating/arrest patients
• Stop heparin before thrombolysis; resume at maintenance dose 3 hours after completion 2
• Contraindications should be ignored in life-threatening PE 2

Transition to Oral Anticoagulation

Preferred: Novel oral anticoagulants (NOACs) 1

• Rivaroxaban: 15 mg twice daily with food for 21 days, then 20 mg once daily with food 5
• Preferred over traditional LMWH-warfarin regimen unless contraindications exist 1

Alternative: Warfarin 2

• Start on day 1 or 2 of heparin therapy 2
• Initial dose: 5-10 mg daily for 2 days 2
• Target INR: 2.0-3.0 2
• Continue heparin for minimum 5 days AND until INR ≥2.0 for at least 24 hours 2
• Check INR every 1-2 days initially until stable 2

Duration of Anticoagulation

Minimum 3 months for all confirmed PE 2, 1

Discontinue after 3 months: 2, 1

• First episode with strong transient/reversible risk factor (recent surgery, immobilization, trauma, pregnancy)

Continue indefinitely: 1

• Unprovoked PE (no identifiable risk factor)
• Recurrent venous thromboembolism
• Active cancer (use LMWH, not NOACs) 1

Re-evaluate at 3-6 months: 1

• Weigh benefits of extended anticoagulation versus bleeding risks
• Consider testing for antiphospholipid antibodies in unprovoked or recurrent PE 1

Special Populations and Contraindications

Triple-positive antiphospholipid syndrome:

• NOACs are contraindicated 5
• Use warfarin (INR 2.0-3.0) instead 1

Active cancer:

• LMWH is superior to NOACs and should be continued indefinitely while cancer is active 1

Renal impairment:

• Avoid rivaroxaban if CrCl <15 mL/min 5
• Use with caution if CrCl 15-30 mL/min; observe closely for bleeding 5

Hepatic impairment:

• Avoid rivaroxaban in moderate (Child-Pugh B) or severe (Child-Pugh C) hepatic impairment 5

Absolute contraindication to anticoagulation:

• Place IVC filter only if anticoagulation is absolutely contraindicated or if recurrent PE occurs despite adequate anticoagulation 2, 1

Discharge Planning and Follow-Up

Before discharge, ensure: 2

• INR is between 2.0-3.0 (if on warfarin)
• General practitioner is aware of anticoagulation and proposed duration
• Patient understands side effects, drug interactions, and has written information
• Anticoagulant supervision appointment is scheduled

Follow-up schedule: 1

• Initial visit: 1-2 weeks after discharge
• Comprehensive assessment: 6-12 weeks
• Yearly examinations for patients on extended anticoagulation

Screen for chronic thromboembolic pulmonary hypertension (CTEPH): 1

• Ask about persistent or new-onset dyspnea or functional limitation at every visit
• If symptomatic after 3 months, implement staged diagnostic workup to exclude CTEPH

Outpatient Management Considerations

Outpatient treatment may be appropriate if: 2

• Patient is not unduly breathless
• No medical or social contraindications exist
• Efficient protocol is in place (similar to outpatient DVT management)