Oral Anticoagulation after Mechanical Heart Valve Replacement: Low Intensity Regimen can Make the Difference

Despite continuous improvement in the field, the ideal prosthetic heart valve remains to be developed. Patients with mechanical prosthetic heart valves are at risk of thrombosis and systemic embolism. The incidence rate of these serious complications is significantly reduced by lifelong Oral Anticoagulant Therapy (OAC) vitamin K antagonist (VKA) therapy. Despite its undeniable benefits, VKA therapy with warfarin is affected by a number of known limitations, including bleeding complications, dietary and drug interactions, and need for international normalized ratio (INR) monitoring and dose adjustments. In particular, the optimal intensity of anticoagulant therapy remains a delicate equilibrium and continues to be an ongoing matter of debate. A significant number of trials has been published on this topic. In this review article we review the pathogenesis of OAC related complications, the evidences supporting current recommendations along with the results of major prospective randomised trials on low intensity OAC regimens and self-management. Safe and effective chronic OAC therapy after mechanical valve replacement requires a thorough examination of patients' features, optimal surgical techniques, state of the art definition of target INR levels and close surveillance. Based on our and other work, we argue that low-dose anticoagulation is safe and feasible in selected mechanical valve recipients and also it may be of benefit during pregnancy. Concurrently, evidence from most recent reports highlights that even higher risk patients' subsets may profit from low intensity protocols. These data postulate that low intensity regimen of OAC coupled with close INR monitoring can make a significant difference for low to intermediate risk patients with aortic mechanical valve replacement. © 2014 Torella M, et al.