Key Points
- Stabilize ABCs; begin targeted evaluation without delaying life-saving therapy.
- Use system-specific risk tools to guide testing and disposition.
- Order high-yield tests first; escalate imaging when indicated.
- Start evidence-based initial therapy and reassess frequently.
Algorithm
- Primary survey and vitals; IV access and monitors.
- Focused history/physical; identify red flags and likely etiologies.
- Order system-appropriate labs and imaging (see Investigations).
- Initiate guideline-based empiric therapy (see Pharmacology).
- Reassess response; arrange consultation and definitive management.
Clinical Synopsis & Reasoning
PE spans from incidental subsegmental disease to obstructive shock. Evaluate pretest probability (e.g., Wells/Geneva), apply age‑adjusted D‑dimer when appropriate, and use CTPA or V/Q based on renal function, pregnancy, and contrast tolerance. Risk‑stratify by RV dysfunction (echo/CT), biomarkers (troponin/BNP), and clinical instability to anticipate decompensation.
Treatment Strategy & Disposition
Anticoagulate promptly when suspicion is high and bleeding risk acceptable; choose DOACs for most stable patients, LMWH in cancer, and UFH if thrombolysis or procedures are possible. Consider systemic thrombolysis or catheter‑directed therapy for massive/submassive PE with deterioration. Assess for precipitating factors and plan duration of therapy (provoked 3 mo; unprovoked often extended). ICU for shock or advanced support; otherwise ward or outpatient pathways for low‑risk cases with reliable follow‑up.
Epidemiology / Risk Factors
- Atherosclerotic risk (HTN, DM, HLD, smoking)
- Age/family history of premature CAD
Investigations
| Test | Role / Rationale | Typical Findings | Notes |
|---|---|---|---|
| EKG | Rhythm/ischemia | ST-T changes/arrhythmia | Serial |
| Troponin | Myocardial injury | Dynamic rise/fall | Trend |
| CXR | Pulmonary edema/size | Cardiomegaly/edema | |
| BMP/Mg2+ | Electrolytes/renal | Derangements | |
| CBC/Coags | Bleeding risk | Abnormal/INR |
Anticoagulation Snapshot
| Agent | Use |
|---|---|
| Direct oral anticoagulant | Outpatient eligible and stable |
| Heparin infusion | Inpatient or planned procedures |
| Thrombolytic | Massive PE with shock when no contraindication |
Pharmacology
| Medication | Mechanism | Onset | Role in Therapy | Limitations |
|---|---|---|---|---|
| Apixaban/Rivaroxaban | Direct factor Xa inhibition | Hours | First-line for most stable PE/DVT | Bleeding; interactions; ED use |
| Enoxaparin (LMWH) | Xa>IIa inhibition | Hours | Preferred initial AC in many stable cases; cancer VTE | Avoid severe renal failure; ED use |
| Unfractionated heparin (IV) | Antithrombin-mediated Xa/IIa inhibition | Immediate | Initial AC when lysis/cath possible or renal failure | Bleeding, HIT; monitor aPTT; ED use |
| Alteplase (systemic) | Plasminogen activation (fibrinolysis) | Rapid | Massive PE with shock or arrest | ICH/major bleed; contraindications; ED use |
| Catheter-directed therapy | Localized fibrinolysis/thrombectomy | Rapid | When systemic lysis high risk or ineffective | Bleeding; expertise required; ED use |
Prognosis / Complications
- Prognosis by ischemic burden/LV function
- Arrhythmias and HF are complications
Patient Education / Counseling
- Explain red flags and when to seek emergent care.
- Reinforce medication adherence and follow-up plan.
Notes
Consider pregnancy, renal failure, and contrast allergy when selecting tests and agents. Engage multidisciplinary response for high risk PE.