Pulmonary Thromboembolism

Pulmonary Thromboembolism (PE) is the obstruction of pulmonary arteries by thrombi, usually originating from deep veins of the lower extremities, leading to impaired perfusion, ventilation-perfusion mismatch, and potential right heart strain.

Definition

Pulmonary Thromboembolism (PE) is the obstruction of pulmonary arteries by thrombi, usually originating from deep veins of the lower extremities, leading to impaired perfusion, ventilation-perfusion mismatch, and potential right heart strain.

Epidemiology

Annual incidence of 60–70 per 100,000 population
More common in adults over 60 years
Slight male predominance
Risk increases with hospitalization, surgery, malignancy, or immobility
Major cause of sudden, preventable death in hospitalized patients

Etiology

Thrombi from deep veins of lower limbs or pelvis (DVT)
Hypercoagulable states: inherited (Factor V Leiden, prothrombin mutation) or acquired (cancer, antiphospholipid syndrome)
Surgery, trauma, or prolonged immobility
Pregnancy and postpartum period
Oral contraceptives or hormone replacement therapy
Central venous catheters or indwelling lines

Pathophysiology

Embolization of thrombus to pulmonary arteries
Partial or complete obstruction of pulmonary arterial blood flow
Increased pulmonary vascular resistance and right ventricular afterload
Right ventricular dilation and strain, leading to right heart failure in severe cases
Ventilation-perfusion mismatch causing hypoxemia
Release of vasoactive mediators causing pulmonary vasoconstriction
Hemodynamic compromise and potential cardiogenic shock in massive PE