Critically evaluate the role of thrombolytic therapy in massive pulmonary embolism.
1. Define the rationale for thrombolysis
Standard therapy for pulmonary embolism is anticoagulation, which prevents additional thrombus from forming, but does not directly dissolve the clot that already exists. Thrombolysis theoretically gives primary treatment as it dissolves fibrin
2. Define massive PE
Massive PE has traditionally been used to describe clot burden on radiology, but this was of little use clinically. Massive PE is more conventionally defined as a cardiogenic shock or SBP <90mmHg due to PE, either confirmed or strongly suspected on clinical grounds.
3. Discuss the evidence in massive PE
The evidence for thrombolysis to improve mortality in massive PE is not strong, but there is a trend towards improved mortality and resolution of shock with thrombolysis. Most guidelines advocate the use of thrombolysis unless absolutely contraindicated i.e. intracranial haemorrhage
4. Discuss the other options if thrombolysis can’t be done in massive PE
If thrombolysis is not possible or contraindicated then the other options for massive PE are surgical embolectomy or catheter embolectomy and fragmentation.
5. Statement of candidate’s approach to thrombolysis in massive PE
This is one of those "critically evaluate" questions; a structured approach is favoured:
Massive PE is defined as a pulmonary embolism of sufficient size to cause systemic arterial hypotension. A submassive PE, in contrast, is one which only causes right heart dysfunction, without obstructive shock.
Rationale for thrombolysis
Evidence for benefits
Evidence for risks
Thrombolysis is an important and potentially lifesaving step in the management of massive PE. If the patient does not meet criteria for thrombolysis, urgent percutaneous or open surgical embolectomy should be considered.
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