Management of Acute Pulmonary Embolism

Immediate Risk Stratification

Hemodynamic instability (sustained systolic blood pressure < 90 mmHg or shock) mandates immediate aggressive therapy, whereas hemodynamically stable patients receive standard anticoagulation. [@1]

Unfractionated heparin should be started immediately (80 U/kg IV bolus or 5,000–10,000 U bolus) without awaiting imaging confirmation. [@4]
Systemic thrombolysis must be administered promptly to all hemodynamically unstable PE patients who do not have a high bleeding risk; delaying therapy increases mortality. [@4]
Thrombolysis regimens
- Cardiac arrest: give alteplase 50 mg IV bolus during CPR. [@4]
- Deteriorating unstable patient: give alteplase 50 mg IV bolus after senior‑consultant notification. [@4]
- Confirmed massive PE in a stable‑appearing patient: give alteplase 100 mg IV infused over 90 minutes. [@4]
Contraindications to thrombolysis may be overridden in life‑threatening PE because the mortality benefit outweighs bleeding risk. [@4]
After thrombolysis, initiate a weight‑adjusted unfractionated heparin infusion 3 hours later, targeting an aPTT of 1.5–2.5 × control. [@4]

When thrombolysis is absolutely contraindicated or fails, surgical pulmonary embolectomy is the preferred alternative. [@3]
Catheter‑directed therapy or extracorporeal membrane oxygenation (ECMO) may be considered for refractory cases, although supporting evidence is limited. [@1]

Validated risk scores (PESI class I/II, sPESI = 0, or Hestia criteria) identify low‑risk patients suitable for outpatient treatment. [@5]
Exclusion criteria for outpatient care include:
- Oxygen saturation < 90 % on room air.
- Severe pain requiring opioid analgesia.
- Chronic kidney disease stage 4–5 (eGFR < 30 mL/min) or severe liver disease.
- Social circumstances that preclude safe home care.
  (All criteria supported by Thorax 2018.) [@5]

In patients eligible for a non‑vitamin‑K oral anticoagulant (apixaban, dabigatran, edoxaban, or rivaroxaban), a NOAC is the recommended first‑line therapy over warfarin. [@1]

A minimum of 3 months of anticoagulation is required for every PE episode. [@1]
Extended anticoagulation beyond 3 months should be considered for:
- Unprovoked PE in patients with low‑to‑moderate bleeding risk.
- Persistent risk factors (excluding antiphospholipid syndrome).
- Minor transient or reversible risk factors.
  (All supported by European Respiratory Journal 2019.) [@1]
After 6 months, a reduced‑dose regimen of apixaban or rivaroxaban may be used for continued prophylaxis. [@1]
Indefinite anticoagulation is mandatory for:
- Antiphospholipid antibody syndrome (use a vitamin‑K antagonist, not a NOAC). [@1]
- Recurrent venous thromboembolism (≥ 1 prior episode) unrelated to major transient risk factors. [@2]

Routine clinical evaluation at 3–6 months after acute PE is required to screen for chronic thromboembolic pulmonary hypertension (CTEPH). [@1]
Patients with persistent symptoms and mismatched perfusion defects on a ventilation‑perfusion scan performed > 3 months after PE should be referred to a pulmonary hypertension expert center. [@1]