Table 1 Suggested risk stratification... | American Society of Hematology

Table 1

Suggested risk stratification scheme for perioperative arterial and venous thromboembolism

Thromboembolic risk category	Clinical indication for warfarin therapy
Thromboembolic risk category	Atrial fibrillation	Mechanical heart valves	Venous thromboembolism
High	CHADS₂ score: 5 or 6 Recent (< 3 months) stroke/TIA Rheumatic valvular heart disease	Any mechanical mitral valve Older aortic mechanical valve (caged-ball, tilting disk) Recent (< 3 months) stroke or TIA	Recent (< 3 months) VTE Severe thrombophilia*
Moderate	CHADS₂ score: 3 or 4	Bileaflet aortic valve prosthesis with at least one risk factor†	VTE within past 3-12 months Non-severe thrombophilia‡ Recurrent VTE Active cancer
Low	CHADS₂ score: 0-2 (without previous stroke or TIA)	Bileaflet aortic bileaflet without any risk factors†	VTE > 12 months ago

Thromboembolic risk category	Clinical indication for warfarin therapy
Thromboembolic risk category	Atrial fibrillation	Mechanical heart valves	Venous thromboembolism
High	CHADS₂ score: 5 or 6 Recent (< 3 months) stroke/TIA Rheumatic valvular heart disease	Any mechanical mitral valve Older aortic mechanical valve (caged-ball, tilting disk) Recent (< 3 months) stroke or TIA	Recent (< 3 months) VTE Severe thrombophilia*
Moderate	CHADS₂ score: 3 or 4	Bileaflet aortic valve prosthesis with at least one risk factor†	VTE within past 3-12 months Non-severe thrombophilia‡ Recurrent VTE Active cancer
Low	CHADS₂ score: 0-2 (without previous stroke or TIA)	Bileaflet aortic bileaflet without any risk factors†	VTE > 12 months ago

Adapted with permission from Douketis J, et al. Chest. 2008;133(6 suppl):299S-339S.⁷

CHADS₂ indicates Cardiac failure-Hypertension-Age-Diabetes-Stroke; VTE, venous thromboembolism; and TIA, transient ischemic attack.

Severe thrombophilia: deficiency of protein C, protein S, or antithrombin; antiphospholipid syndrome, or multiple abnormalities.

Risk factors: atrial fibrillation, cardiac failure, hypertension, age > 75 years, diabetes, stroke, or TIA.

Non-severe thrombophilia: heterozygous factor V or factor II mutation.