Risk factors for DVT/PE:
Immobility, w/risk increasing based on duration, e.g. long car ride, plane ride, bed bound
Active cancer → in particular mucin secreting adenocarcinomas, NHL, AML, others
Meds, toxins→ e.g. smoking, estrogen
Trauma/vascular injury, surgery
Chronic intravascular catheters
Pregnancy - w/hypercoag state extending ~6w post-partum
Chronic inflammatory conditions→ IBD, lupus, Behcet's dz, etc
Prior hx DVT or PE
Biochemical predispositions, consider in particular when unexplained DVT: protein S or C deficiency, Anti-thrombin 3 defic, Prothrombin mutation, factor 5 leiden resistance, anti-phospholipid AB (arterial and venous)
Acquired predispositions, often linked to clots in unusual places: nephrotic syndrome (renal vein), p vera (hepatic vein), HIT, ET (arterial and venous), PNH, hyperhomocystinemia
Mechanical predispositions that compress veins→ stasis→ clot
Can have contribution from more than one RF

CT-angiography typically definitive for identifying emboli
V/Q scan less commonly used, unless concern for chronic PE or renal insufficiency limits use CT-a
Ultrasound used to identify DVT
D-Dimer useful in setting of low (and sometimes intermediate) pre-test probability DVT/PE to exclude VTE (high sensitivity)

Pulmonary Embolism