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Pulmonary Embolism — Risk Stratification, Anticoagulation, and Thrombolysis

System: Pulmonology • Reviewed: Sep 2, 2025 • Step 1Step 2Step 3

Synopsis:

Suspect PE with unexplained dyspnea, pleuritic pain, or syncope. Use Wells/Geneva and D-dimer to select imaging. Start anticoagulation when probability is high and bleeding risk acceptable. Thrombolysis or catheter therapy is reserved for massive PE (shock) and selected submassive cases with RV dysfunction and clinical deterioration.

Key Points

  • Use the highest‑yield diagnostic test early; do not let testing delay time‑critical therapy.
  • Set objective targets and reassess frequently.
  • Plan definitive source control or disease‑specific therapy when indicated; document follow‑up and patient education.

Algorithm

  1. Assess pretest probability → D-dimer vs direct imaging.
  2. If high probability and low bleed risk, start anticoagulation before imaging if delays expected.
  3. Identify massive vs submassive vs low-risk; consider thrombolysis/catheter therapy when indicated; arrange follow-up for provoked/unprovoked PE and cancer screening.

Clinical Synopsis & Reasoning

Suspect PE with unexplained dyspnea, pleuritic pain, or syncope. Use Wells/Geneva and D-dimer to select imaging. Start anticoagulation when probability is high and bleeding risk acceptable. Thrombolysis or catheter therapy is reserved for massive PE (shock) and selected submassive cases with RV dysfunction and clinical deterioration.


Treatment Strategy & Disposition

Stabilize ABCs. Initiate guideline‑concordant first‑line therapy with precise dosing and continuous monitoring. Escalate to advanced/procedural interventions based on explicit failure criteria. Define ICU, step‑down, and ward disposition triggers; involve specialty teams early.


Epidemiology / Risk Factors

  • Risk varies by comorbidity and precipitants; see citations for condition‑specific data.

Investigations

TestRole / RationaleTypical FindingsNotes
Wells/Rev Geneva + D-dimerPretest probabilityRule-out strategy in low/moderate riskAvoid unnecessary CTPA
CTPA (first-line) or V/Q (if contrast contraindicated)DiagnosisFilling defects or mismatched perfusion defect
Troponin/BNP and echocardiographyRiskRV strain identifies submassive PEGuides disposition

High-Risk & Disposition Triggers

TriggerWhy it mattersAction
Hypotension (SBP <90) or shockMassive PEActivate PE team; thrombolysis or thrombectomy; ICU
RV strain (echo/CT) with elevated troponin/BNPSubmassive PEConsider catheter-directed therapy
Active bleeding/high bleed riskThrombolysis hazardHeparin only; consider IVC filter if anticoagulation contraindicated
Pregnancy or cancerComplex courseSpecialist input; LMWH preferred
Severe hypoxemia or recurrent syncopeInstabilityICU monitoring

Pharmacology

Medication/InterventionMechanismOnsetRole in TherapyLimitations
UFH/LMWH or DOACs (apixaban/rivaroxaban)AnticoagulationHoursFirst-line therapyLMWH preferred in cancer/pregnancy
Systemic thrombolysis (e.g., alteplase 100 mg over 2 h) for massive PEFibrinolysisHoursHemodynamic rescueBleeding risk high
Catheter-directed thrombolysis/thrombectomyInterventionalHoursSelected submassive/massivePE response team decision

Prognosis / Complications

  • Outcome depends on timeliness of diagnosis and definitive therapy; monitor for complications.

Patient Education / Counseling

  • Provide red‑flag education, adherence guidance, and explicit return precautions; arrange timely specialty follow‑up.

References

  1. ESC/ACCP PE guidelines — Link

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