Is it safe and effective to reduce the target anticoagulation range for patients with mechanical prosthetic aortic valves?

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was ‘Is it safe and effective to reduce the target anticoagulation range for patients with mechanical aortic valves?’ Altogether 922 papers were found using the reported search, of which 7 represented the best evidence to answer the clinical question. Only studies that compared high (target international normalized ratio 2–3) versus low (target international normalized ratio