Mechanical	Biological
Durable—valves lasting 20-30 years	Limited life span—10% of homografts and 30% of heterografts fail within10-15 years
Thrombogenic—patients require lifelong anticoagulant therapy	Low thrombogenic potential—lifelong anticoagulation is not required
Preferred in younger patients with >10-15 years life expectancy	Preferred in older patients with <10-15 years life expectancy
Preferred in patients who require lifelong anticoagulant therapy	Preferred in those who cannot (or will not) take lifelong anticoagulant therapy