Perioperative risk of DVT

	DVT (%)		PE (%)
Level of Risk	Calf	Proximal	Clinical	Fatal	Successful Prevention Strategies
Low risk: Minor surgery in patients <40 yr with no additional risk factors	2	0.4	0.2	<0.01	No specific prophylaxis; early and aggressive mobilization
Moderate risk: Minor surgery in patients with additional risk factors; surgery in patients 40-60 yr with no additional risk factors	10-20	2-4	1-2	0.1-0.4	LDUH q12h, LMWH <3400 U daily, GCS, or IPC
High risk: Surgery in patients >60 yr, or 40-60 yr with additional risk factors (prior VTE, cancer, molecular hypercoagulability)	20-40	4-8	2-4	0.4-1.0	LDUH q8h, LMWH >3400 U daily, or IPC
Highest risk: Surgery in patients with multiple risk factors (age >40 yr, cancer, prior VTE); hip or knee arthroplasty, HFS; major trauma; SCI	40-80	10-20	4-10	0.2-5	LMWH (>3400 U daily), fondaparinux, oral VKAs (INR, 2-3), or IPC or GCS + LDUH or LMWH

DVT, deep venous thrombosis; GCS, graduated compression stockings; HFS, hip-fracture surgery; INR, international normalized ratio; IPC, intermittent pneumatic compression; LDUH, low-dose unfractionated heparin; LMWH, low-molecular-weight heparin; PE, pulmonary embolism; SCI, spinal cord injury; VKA, vitamin K antagonist; VTE, venous thromboembolism.

Adapted from Geerts WH, Pineo GF, Heit JA. Prevention of venous thromboembolism: The Seventh ACCP Conference on Antithrombotic and Thrombolytic Therapy. Chest 2004;126:338S-400S.