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Pulmonary Embolism

Pulmonary embolism (PE) is the most common form of pulmona~y heart disease. The presentation of PE can be extremely variable. It can present with an emergency or go unnoticed depending on the magnitude of the thrombus and associated hypoxia and circulatory changes.


 
Venous Thrsmboembolism (VTE)

VTE consists of two related conditions: Deep vcin thrombosis (DVT) and pulmonary embolism (PE).Despite advances in diagnosis and treatment, VTE remains a potentially life-threatening disorder affecting hospitalized patients as well as osteilsibly heallhy individuals. It has been estimated that the yearly incidence of dcep venous thrombosis (DVT) is as high as 250, 000 cases in the United States alone and as many as 100,000 patients die annually fro111 PE. In addition to early risk of PE, late morbidity may develop from recurrent thrombosis and the post thrombotic syndrome.

Most PE result from thrombi that originate in the dcep veins of the leg, pelvic veins and rarely thrombi in the axillay or subclavian veins embolize to the pulmonary arteries. On the other hand many patients with PE inay not have detectable DVT. In 1884, Rudolph Virchow first proposed that thrombosis was the result of at least 1 of 3 underlying etiologic factors: vascular endothelial damage, stasis of blood flow, and hyper-coagulability of blood. It is now well documented that amongst patients treated for VTE, majority have atleast one risk factol; Furthermore, there is convincing evidence that risk increases in proportion to the number of predisposing factors. The risk factors1 predisposing factors convincingly demonstrated for VTE are shown in Table

When venous thrombi detach from their sites of formation, they flow through the venous system toward the pulmonary arterial circulation and the colldition is called as PE. If an embolus is extremely large, it may lodge at the bifurcation of the pulmonary artery,forming a saddle embolus. More commonly, a major p~llmonary vessel is occluded.


Other Causes of PE The commonest cause of PE remains venous thromboembolic disease (Table ) which can be precipitated by host of conditions as described in Table . The other uncommon causes of PE include embolization of vegetations, tumor mass from right heart to pulmonary circulation. Rarely, fat, air or amniotic fluid er~lbolization can occur (Table ).

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