What is the approach to managing a patient with pulmonary embolism?

Approach to Pulmonary Embolism

Start anticoagulation immediately when PE is suspected based on clinical probability, even before diagnostic confirmation is complete, unless the patient has active bleeding or absolute contraindications. 1

Initial Assessment and Risk Stratification

Hemodynamic Status Evaluation

• Perform bedside transthoracic echocardiography (TTE) immediately in patients presenting with hemodynamic instability to differentiate high-risk PE from other acute life-threatening conditions 1
• Identify high-risk PE by presence of systemic hypotension (systolic BP <90 mmHg), cardiogenic shock, or sudden collapse with elevated jugular venous pressure 1
• Recognize that most PE patients present with breathlessness and/or tachypnea (respiratory rate >20/min) 1, 2

Clinical Probability Assessment

• Use validated diagnostic algorithms incorporating standardized clinical probability assessment and D-dimer testing to avoid unnecessary imaging and radiation exposure 1
• Score major risk factors including: recent immobilization or major surgery, recent lower limb trauma/surgery, clinical deep vein thrombosis, previous proven DVT/PE, pregnancy/postpartum, or major medical illness 1, 2
• Consider classic presentations: sudden collapse with raised JVP, pulmonary hemorrhage syndrome (pleuritic pain/hemoptysis), or isolated dyspnea 1, 2
• Note that PE is rare in patients under age 40 without risk factors 1, 2

Diagnostic Testing

• Normal D-dimer levels exclude PE in patients with low to intermediate clinical probability 1
• Proceed to CT pulmonary angiography (CTPA) for patients with high clinical probability or elevated D-dimer 1
• If CTPA reports single subsegmental PE, consider false-positive findings and discuss with radiology for second opinion before committing to anticoagulation 1

Immediate Anticoagulation Management

Hemodynamically Stable Patients

Prefer novel oral anticoagulants (NOACs) over traditional LMWH-warfarin regimen unless contraindications exist 1

NOAC Therapy (First-Line)

• Rivaroxaban 15 mg twice daily for 21 days, then 20 mg once daily for treatment of acute PE 3
• Administer with food to ensure optimal absorption 3
• Avoid rivaroxaban in hemodynamically unstable patients who may require thrombolysis or pulmonary embolectomy 3
• Do not use in patients with CrCl <30 mL/min, moderate-to-severe hepatic impairment (Child-Pugh B or C), or triple-positive antiphospholipid syndrome 3

Alternative: Weight-Adjusted Heparin

• Initial bolus: 80 IU/kg IV, followed by continuous infusion of 18 IU/kg/hour 1, 2
• Target aPTT 1.5-2.5 times control (45-75 seconds) 1, 2
• Check aPTT 4-6 hours after initial bolus, then daily once therapeutic 1, 2
• Failure to achieve adequate anticoagulation (aPTT >1.5 times control) within 24 hours is associated with 25% risk of recurrent VTE 4
• Continue heparin for 7-10 days while overlapping with warfarin during last 4-5 days 1, 4

Warfarin Transition

• Target INR 2.0-3.0 (therapeutic range 2.0-3.0) 1, 5
• Continue heparin until INR therapeutic for 2 consecutive days 1

Hemodynamically Unstable Patients (High-Risk PE)

Systemic thrombolysis is indicated for patients with systemic hypotension or cardiogenic shock 1, 2

Thrombolytic Regimens

• rtPA: 100 mg IV over 2 hours (first-line) 1, 2
• Streptokinase: 250,000 units over 20 minutes, then 100,000 units/hour for 24 hours (plus hydrocortisone to prevent circulatory instability) 1
• Urokinase: 4,400 IU/kg over 10 minutes, then 4,400 IU/kg/hour for 12 hours 1
• Stop heparin before thrombolysis; resume maintenance dose after completion 1

Rescue Interventions

• Consider surgical embolectomy if thrombolysis is contraindicated or fails to produce clinical improvement within one hour 1
• Catheter-directed treatment is an alternative reperfusion option when surgical expertise is available 1

Intermediate-High Risk PE

• Reperfusion is not first-line treatment 1
• Prospectively plan management strategy with contingency plan ready if clinical deterioration occurs 1
• Monitor closely for signs of hemodynamic decompensation requiring escalation to thrombolysis 1

Special Populations

Cancer Patients

• Low molecular weight heparin (LMWH) is superior to NOACs and should be continued indefinitely while cancer is active 6
• The optimal anticoagulant regimen after the first 6 months requires further study 1

Pregnant Patients

• Consider diagnostic pathways including CTPA or V/Q scan, which can be used safely during pregnancy 1
• Anticoagulation dosing in pregnancy has not been well-studied; promptly evaluate any signs of blood loss 3

Antiphospholipid Syndrome

• Test for antiphospholipid antibodies in unprovoked or recurrent PE 6
• NOACs are contraindicated in triple-positive APS; use warfarin (INR 2.0-3.0) instead 6, 3

Duration of Anticoagulation

Initial Treatment Phase

• Minimum 3 months anticoagulation for all confirmed PE 1, 5
• Continue for 3 months if PE provoked by major transient/reversible risk factor 1, 6

Extended Therapy Decision (After 3-6 Months)

Re-examine patient after initial 3-6 months to weigh benefits versus bleeding risks for extended anticoagulation 1

• Discontinue after 3 months: First episode with strong transient/reversible risk factor 1, 6
• Continue indefinitely: Unprovoked PE, recurrent VTE, or active cancer 1, 6
• Consider reduced-dose anticoagulation for extended therapy to minimize bleeding risk 1

Contraindications and Filters

IVC Filter Indications

Place IVC filter only in patients with: 1

• Absolute contraindication to anticoagulation, OR
• Recurrent PE despite adequate anticoagulation 1

Follow-Up and Long-Term Monitoring

Structured Follow-Up Schedule

• Initial follow-up within 1-2 weeks of discharge 7
• Comprehensive assessment at 6-12 weeks 7
• Yearly examinations for patients on extended anticoagulation 1

Surveillance for Complications

• Ask about persistent or new-onset dyspnea or functional limitation at every visit 1
• If symptomatic after 3 months, implement staged diagnostic workup to exclude chronic thromboembolic pulmonary hypertension (CTEPH) 1, 7
• Screen for VTE recurrence, occult malignancy, and bleeding complications 1
• Routine follow-up imaging is not recommended in asymptomatic patients 1

Critical Pitfalls to Avoid

• Never delay anticoagulation while awaiting diagnostic confirmation in high or intermediate probability cases 1
• Do not use rivaroxaban as initial therapy in hemodynamically unstable PE requiring potential thrombolysis 3
• Avoid premature discontinuation of anticoagulation, as this increases thrombotic risk 3
• Do not lose patients to follow-up after acute treatment; lifelong VTE recurrence risk exists except when provoked by strong transient factors 1
• Ensure adequate initial anticoagulation intensity to prevent the 25% recurrence rate associated with subtherapeutic dosing 4