Most pulmonary emboli (PE) arise from deep venous thrombosis (DVT) of the proximal veins of the lower extremities (iliac, femoral, and popliteal). The clinical presentation of pulmonary embolism is variable and often nonspecific, making the diagnosis challenging. DVTs are dangerous since they can result in PE which can be deadly.

The underlying causes of DVT and PE may be hereditary (genetic mutations) or acquired. Hereditary causes are rare and include Factor V Leiden, elevated Factor VIII, and deficiencies in protein S, protein C, and antithrombin.

Acquired causes are more common. Precipitating factors for DVT and subsequent PE, include:

• Immobilization due to hospitalization, travel, obesity, or stroke;
• Adverse effects of drugs, such as steroids, oral contraceptives, anticoagulants, and heparin;
• Clinical conditions including major trauma, pregnancy, malignancy, diabetes, and myeloproliferative disorders; and
• Autoimmune diseases such as lupus anticoagulant and antiphospholipid syndrome.

Immobilization leads to venous stasis with accumulation of clotting factors and fibrin, resulting in blood clot formation. 

Healthcare-associated venous thromboembolism (VTE) is a result of hospitalization, surgery, or other healthcare treatment or procedure. According to the CDC, although anyone can develop a DVT, over half are related to a recent hospitalization or surgery and most occur after discharge; approximately 70% of these could be prevented.   

Acute, Chronic, or "History of" DVT and PE

The acuity of DVT and PE should be identified for clinical and coding purposes:

• Acute,
• Chronic, or
• “History of”

Acute DVT or PE is usually treated with heparin-type medications for immediate anticoagulation to prevent further clot growth. None of these medications actually “treat” the acute DVT. The acute blood clots are usually dissolved spontaneously by endogenous processes in the veins within a few days, not by heparin, Coumadin, or Xarelto. A transition is then made to intermediate term (3-12 months) Xarelto or Eliquis, to prevent recurrent DVT/PE.

The first episode of PE or DVT is acute until the clot(s) have resolved – approximately 10-14 days. After that it should be considered resolved, i.e., “history of”, even though anticoagulation to prevent a recurrence is continued up to one year. A subsequent DVT/PE episode requiring admission (or not) would constitute a "recurrent" episode of acute DVT or PE. 

Chronic DVT is a residual clot or fibrosis of a clot that continues to cause deep venous obstruction resulting in edema, pain, or chronic venous ulcers. Chronic PE is a persistent clot or fibrosis causing blockage in pulmonary arteries and chronic pulmonary hypertension. Both require life-long (> 1 year) anticoagulant therapy, such as Eliquis, Xarelto, or Coumadin.

The acute episode of DVT and PE ends when the patient is stabilized, transitioned to Eliquis or Xarelto, and discharged. If such a patient is admitted with “history of DVT (or PE)” and without residual clot or symptoms, the correct status is “history of” DVT/PE, not acute or chronic DVT/PE.

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