Term | Definition and examples |
No identifiable risk factor (unprovoked) | VTE where no identifiable provoking event or risk factor is evident |
Identifiable risk factor (provoked) | VTE caused by a known event or risk factor (eg, surgery, hospital admission, estrogen) |
Transient risk factor | Risk factors for VTE that are reversible - Major risk factors (ie, transient factors that favor limited-duration anticoagulation):
- Major surgery >30 minutes, hospitalization or confined to bed with "bathroom privileges" for ≥3 days due to acute illness, CS, trauma with fractures, estrogen therapy, pregnancy or puerperium
- Minor risk factors (ie, transient factors that favor continuing anticoagulation):
- Minor surgery <30 minutes, hospitalization <3 days, reduced mobility at home ≥3 days due to acute illness, lower extremity injury without fracture with reduced mobility ≥3 days, long-haul flight
|
Persistent risk factor | Risk factors that persist over a prolonged period of time - Examples include irreversible conditions such as active malignancy, obesity, active inflammatory bowel disease, active autoimmune disease, continued hormonal therapy, nephrotic syndrome, recurrent long-haul flights
|
Proximal DVT of lower extremity | VTE that is in the popliteal, femoral, or iliac veins |
Distal DVT of lower extremity | VTE that is without a proximal component and confined to the calf veins (peroneal, posterior, anterior tibial, and muscular veins) |
Pulmonary embolism | Thrombus in the main, segmental, or subsegmental branches of the pulmonary artery |
Initial anticoagulation | Anticoagulant therapy that is administered immediately following a diagnosis of VTE |
Anticoagulation following initial phase | Anticoagulant therapy that is typically administered for a finite time period (ie, scheduled stop date, typically 3 months) |
Extended anticoagulation | Anticoagulant therapy that is administered beyond the typical 3 months but with a scheduled stop date (eg, 6 to 12 months) |
Indefinite anticoagulation | Anticoagulant therapy that is administered beyond the typical 3 months but without a scheduled stop date |
DOACs | Also known as newer/novel oral anticoagulants (NOAs), non-vitamin K antagonist oral anticoagulants (NOACs), and target-specific oral anticoagulants (TOACs, TSOACs) |