Evidence-based estimates of outcome after aortic valve replacement using a microsimulation model

Prognosis after aortic valve replacement (AVR) is determined by multiple interrelated factors. Standard statistical methods do not allow detailed insight into the factors that affect outcome in the individual patient The application of a microsimulation model to predict age- and gender-specific outcome is illustrated using reported estimates of the occurrence of valve-related events and outcomes after AVR with different aortic valve substitutes. Compared to healthy age-matched individuals, the life expectancy of patients after AVR is markedly reduced, especially in the younger age groups. This reduction is mainly due to excess mortality, while valve-related events play a minor role. Re-operation for structural valve deterioration is common in younger patients with tissue valves. Patients with mechanical valves have a high lifetime risk of suffering thrombo-embolic and bleeding events. The life expectancy of old patients is near-normal, illustrating a healthy-patient effect. Microsimulation allows detailed insight into the factors that affect survival after AVR. Microsimulation provides a useful and objective decision support tool.