Synopsis
Use the NICE Wells/D-dimer/CTPA pathway, start timely anticoagulation, identify haemodynamic instability and decide duration and follow-up safely.
- PE ranges from incidental segmental clot to obstructive shock; haemodynamic instability overrides routine outpatient diagnostic sequencing.
- If overall clinical suspicion is low and another diagnosis is feasible, consider the PERC rule to decide whether further PE testing is needed.
- Use the 2-level PE Wells score: more than 4 means PE likely and prompts immediate CTPA; 4 or less means PE unlikely and prompts D-dimer first.
Key red flags
Cardiac arrest, persistent hypotension, shock, altered mentation, cool peripheries or rising lactate indicates obstructive RV failure and needs immediate reperfusion assessment.
Investigation priorities
Select who needs no test, D-dimer or immediate imaging.
Management branches
PE suspected without haemodynamic instability
- If clinical suspicion is low and another diagnosis is feasible, consider PERC; otherwise calculate the 2-level PE Wells score.
- If Wells >4, arrange immediate CTPA; if imaging is delayed, give interim therapeutic anticoagulation after baseline bloods unless contraindicated.
Imaging-confirmed PE without shock
Key medicines
Apixaban10 mg orally twice daily for 7 days, then 5 mg twice daily. If extended prevention is indicated after 6 months of treatment, 2.5 mg twice daily is the licensed recurrence-prevention dose.
Rivaroxaban15 mg orally twice daily with food for 21 days, then 20 mg once daily with food. After day 21 in creatinine clearance 15–49 mL/min, the SmPC allows considering 15 mg once daily if bleeding risk outweighs recurrence risk, but this is pharmacokinetic modelling and was not studied clinically. After at least 6 months, 10 mg once daily (or 20 mg once daily when recurrence risk is high) is licensed for extended prevention.