Venous thromboembolism classification scheme

Editors-in-Chief: C. Michael Gibson, M.S., M.D. Associate Editor-In-Chief: Ujjwal Rastogi, MBBS [mailto:urastogi@perfuse.org]

Overview
Venous thromboembolism (VTE) is an inherently broad parent term which houses two related conditions: deep vein thrombosis (DVT) and pulmonary embolism (PE).

Classification Scheme
VTE is classified in two ways. First, by where the thrombosis formation occurs. Second, by additional attributes specific to thrombosis formation in that area of the body.

I. Deep venous thrombosis refers to the formation of a thrombosis that is in a deep vein.
 * Clinical considerations for furthered classification:
 * Superficial versus deep: A palpable thrombus formation is classified as a superficial venous thrombus. Clots forming in the lower leg and thigh vasculature (lesser and greater saphenous veins, respectively) or the forearm and upper arm vasculature (radial, ulnar, cephalic and basilic vein, respectively) are also superficial.
 * Thrombus formation in the brachiocephalic veins, the internal jugular and the superior vena cava are classified as deep.
 * Proximal versus distal:
 * Proximal venous thrombosis refers to thrombus formation in the popliteal vein or higher. Vasculature commonly involved in a proximal thrombosis include the femoral vein, common femoral vein, iliac vein, and the inferior vena cava.
 * Distal or calf vein thrombosis refers to thrombus formation in one of the three major paired veins in the calf below the popliteal vein. It can also refer to muscular branches of the gastrocnemius and soleus muscle. Vasculature involved in a distal formation include the anterior tibial, posterior tibial and peroneal veins.
 * Subacute versus acute:
 * Subacute thrombosis refers to thrombosis formation involving a narrowing of the vein involved and a hyperechogenic clot; flow may be partially obstructed by this narrowing.
 * Acute thrombosis can refer to:
 * A vein with a thrombus that is normal or, even, wider than usual with the contralateral side of the vein being unaffected.
 * A clot that, during ultrasound echos, is not dense.
 * A clot that may totally or partially obstruct blood flow.
 * In the evaluation of the upper extremity, the subclavian and brachiocephalic veins inability to be compressed may pose challenges for determining subacute versus acute status.

'''II. Pulmonary embolism:''' It is mainly classified as following: Acute PE are also classified as Massive pulmonary embolism or Submassive pulmonary embolism or Low-risk pulmonary embolism.
 * Acute
 * Silent
 * Symptomatic
 * Fatal
 * Chronic