Table 5.

Risk stratification for perioperative arterial or venous thromboembolism29,30

Risk stratification	High	Intermediate	Low
	• Any mechanical mitral valve • Mitral/aortic caged ball or tilting disc valve • MHV with history of stroke or TIA in previous 6 months • CHADS2 >5 • Atrial fibrillation with history of stroke or TIA in previous 3 months • Recent (within 3 months) VTE • Deficiency of protein C, protein S, or antithrombin • Presence of antiphospholipid antibodies	• Bileaflet AVR plus major risk factors for stroke • CHADS2 score of 3 or 4 • VTE within 3–12 months • Heterozygous factor V Leiden, prothrombin gene mutation • Active cancer (treatment within 6 months or palliative) • Recurrent VTE	• Bileaflet AVR without major risk factors for stroke • CHADS2 score of 0–2 • No prior stroke or TIA • No VTE in previous 12 months
Anticoagulation recommendations	Bridging anticoagulation recommended	Bridging anticoagulation if low bleeding risk	Bridging anticoagulation not required

Abbreviations: VTE, venous thromboembolism; ATE, arterial thromboembolism; AVR, aortic valve replacement; MHV, mechanical heart valve; CHADS₂, congestive heart failure, hypertension, age >75 years, diabetes mellitus, stroke history; TIA, transient ischemic attack.