Table 5.

Suggested risk stratification for perioperative thromboembolism.¹³ CHA₂DS₂ VASc, congestive heart failure, hypertension, age ≥75 (doubled), diabetes mellitus, prior stroke or transient ischaemic attack (doubled), vascular disease, age 65–74, female; TIA, transient ischaemic attack (range 0-9). VKA, vitamin K antagonist. CHADS₂ score: CHAD=1 point each; S=2 points (range: 0–6)

Risk stratum	Indication for VKA therapy			Bridge?
	MHV	AF	VTE
High	Mitral valve prosthesis: any type Aortic valve prosthesis: caged ball and tilting disc Stroke/TIA <6 months prior	CHA2DS2 VASc score: 7–9 Rheumatic valvular heart disease Stroke/TIA <3 months prior	Severe thrombophilia: deficiency of protein C and protein S, and antithrombin and antiphospholipid antibodies Stroke/TIA <3 months prior	Bridging advised
Moderate	Aortic valve prosthesis: bi-leaflet (and one or more of the following risk factors: AF, prior stroke or TIA, hypertension, diabetes, congestive heart failure, and age >75 yr)	CHA2DS2 VASc score of 5 or 6 (without prior stroke or TIA)	VTE 3–12 months prior Non-severe thrombophilia: heterozygous factor V Leiden and prothrombin gene mutation Recurrent VTE Active cancer	Likely no bridging AF group Consider bridging VTE and MHV
Low	Aortic valve prosthesis: bi-leaflet (without other risk factors)	CHA2DS2 VASc score of 0–4 (without prior stroke or TIA)	VTE >12 months prior and no other risk factors	No bridging