Massive pulmonary embolism
A massive pulmonary embolism (PE) represents the most severe manifestation of venous thromboembolic disease when classified on a continuum of hemodynamic derangement. It is usually characterized by an acute pulmonary embolism accompanied by one or more of the following
- sustained systemic hypotension (systolic blood pressure <90 mm Hg) for at least 15 minutes or which requires inotropic support
- which is not primarily due to another cause, such as left ventricular dysfunction, sepsis, hypovolemia or an arrhythmia
- persistent and profound bradycardia
- defined by the presence of a heart rate < 40 bpm associated with signs of end organ hypoperfusion
Massive pulmonary embolism carries a high mortality rate despite advances in diagnosis and therapy.
Treatment and prognosis
Reversal of the associated hypotension and hypoxia with supplemental oxygen and inotropes/vasopressors should be performed to prevent circulatory collapse. As with other forms of venous thromboembolism, anticoagulation is usually initiated .
Intravenous administration of systemic thrombolytics, such as recombinant tissue type plasminogen activator (rtPA), may be considered. Systemic administration may be preferable to catheter-directed thrombolysis, although this remains controversial. Thrombolytic administration may reduce the clot burden, resulting in an improvement in hemodynamics; however, there is an attendant risk of major arterial bleeding. Absolute contraindications to systemic thrombolytic administration include the following:
- structural intracranial lesions
- history of intracranial hemorrhage
- recent (within 3 months) ischemic stroke
- active bleeding
- presence of a bleeding diathesis
- recent spine or brain surgery
- recent traumatic brain injury
Failure of systemic thrombolytics to resolve hemodynamic instability may warrant surgical or catheter-assisted embolectomy. These may also be considered when thrombolytic administration is contraindicated due to an unacceptably high risk of bleeding.