17th January 2024

Management 

The first step of managing an acute PE involves a similar approach to any other acute medical scenario by assessing the patient in an ABCDE fashion, identifying and treating features such as hypoxia and hypotension. Once the patient has been stabilised, it is important to risk stratify patients into low, intermediate and high-risk categories. The Pulmonary Embolism Severity Index (PESI) and, later, the simplified PESI (sPESI) have been developed to help clearly delineate risk by calculating 30-day mortality. This should be calculated for any patient presenting with a confirmed PE, unless there is clear evidence of haemodynamic compromise on presentation, in which case a medical emergency algorithm approach should be taken to proceed immediately to thrombolysis. An sPESI score of one or more indicates the patient is at least intermediate risk and should be managed as an inpatient. If the sPESI score is zero, in some scenarios, the patient can be managed on an ambulatory basis (5).

High-risk features in PE:

• Haemodynamic instability – persistent hypotension <90mmHg or a systolic drop of ≥40mmHg lasting for 15 or more minutes, not caused by new-onset arrhythmia, hypovolaemia or sepsis.
• sPESI score of  ≥1
• Features of right ventricular dysfunction on TTE or CTPA
• Elevation of cardiac troponin levels

Table 3 – sPESI score.

Table 3. Source: Jimenez D. Simplified PESI (Pulmonary Embolism Severity Index) – MDCalc [Internet]. Mdcalc.com. Available from: https://www.mdcalc.com/simplified-pesi-pulmonary-embolism-severity-index#use-cases

Pharmacological Management

Anticoagulation

The mainstay of treatment for PE is early anticoagulation. When there is a high clinical suspicion, anticoagulation should be started even prior to confirmation of PE on diagnostic tests. Most commonly, the anticoagulant of choice is once-daily subcutaneous low molecular weight heparin (LMWH) or fondaparinux at a weight-adjusted therapeutic dose. Alternatively, there is also now good evidence for oral anticoagulation with a non-vitamin K oral anticoagulant (NOAC) agent, such as apixaban or rivaroxaban. In the case of poor renal function or significant bleeding risk, unfractionated heparin can be used, although this is associated with a higher risk of heparin-induced thrombocytopenia.

Warfarin monotherapy is not used in the acute setting, as it normally requires several days to reach the required therapeutic range for international normalised ratio (INR). When it is being used as a long-term anticoagulation agent, concurrent use of a LMWH must be maintained until the INR is within the therapeutic range of 2.0-3.0. Following the acute period, all patients will need a period of long-term anticoagulation to prevent recurrence. Most patients can be converted to NOAC treatment, but for patients with active malignancy, guidelines recommend remaining on LMWH, which has been found to be significantly more efficacious at reducing recurrence of VTE than oral agents (6).

Table 4 – Recommendations for anticoagulation in PE

Reperfusion treatment

• Systemic thrombolysis – for patients with features of haemodynamic compromise as defined above (‘massive PE’), intravenous thrombolysis can be undertaken with agents such as recombinant tissue-type plasminogen activator (alteplase) or streptokinase, in the absence of major bleeding risk factors.
• Catheter-directed thrombolysis – there is growing use of targeted thrombolysis therapy and mechanical thrombectomy using percutaneous approach via pulmonary artery catheterisation.
• Surgical embolectomy – open embolectomy of the pulmonary artery clots requiring cardio-pulmonary bypass (7).

Supportive management

• Respiratory support is often required in PE, ranging from nasal cannulae and simple face mask oxygen support to invasive ventilation and, rarely, extracorporeal membrane oxygenation (ECMO).
• Haemodynamic support – intravenous fluids, and in some cases, vasopressor and inotropic support.
• Multidisciplinary pulmonary embolism response teams (PERTs) – there is a growing use of MDTs comprising members from various disciplines, including cardiology, haematology and interventional radiology, amongst others, to make clinical decisions on optimal PE management on an individual basis.

Reperfusion treatment

• Systemic thrombolysis – for patients with features of haemodynamic compromise as defined above (‘massive PE’), intravenous thrombolysis can be undertaken with agents such as recombinant tissue-type plasminogen activator (alteplase) or streptokinase, in the absence of major bleeding risk factors.
• Catheter-directed thrombolysis – there is growing use of targeted thrombolysis therapy and mechanical thrombectomy using percutaneous approach via pulmonary artery catheterisation.
• Surgical embolectomy – open embolectomy of the pulmonary artery clots requiring cardio-pulmonary bypass (7).

Supportive management

• Respiratory support is often required in PE, ranging from nasal cannulae and simple face mask oxygen support to invasive ventilation and, rarely, extracorporeal membrane oxygenation (ECMO).
• Haemodynamic support – intravenous fluids, and in some cases, vasopressor and inotropic support.
• Multidisciplinary pulmonary embolism response teams (PERTs) – there is a growing use of MDTs comprising members from various disciplines, including cardiology, haematology and interventional radiology, amongst others, to make clinical decisions on optimal PE management on an individual basis.

Internal vena cava filters

In patients where anticoagulation in PE is absolutely contraindicated, insertion of an internal vena cava (IVC) filter can be considered. Theoretically, these prevent recurrent PEs from occurring by mechanically blocking the travel of potential venous thromboemboli into the proximal circulation. Whilst they do decrease risk of recurrent PE, they are actually associated with a significantly increased risk of DVT, likely due to instrumentation in the absence of anticoagulation, and thus have no mortality benefit overall.