Factor XI Deficiency: Phenotypic Age-Related Considerations and Clinical Approach Towards Bleeding Risk Assessment

Authors: Barg, AA.; Livnat, T; Kenet, G

Affiliations: Sheba Medical Center, Tel Hashomer, Israel. The National Hemophilia Centre, The Amalia Biron Thrombosis Research Institute.

Publication: Blood. 2024

ABSTRACT: Factor XI (FXI) deficiency is a rare bleeding disorder that presents complex challenges in patient assessment and bleeding risk management. Despite generally causing mild to moderate bleeding symptoms, clinical manifestations can vary, and bleeding tendency does not always correlate with FXI plasma levels or genotype. Our manuscript delves into the age-related nuances of FXI deficiency across an individual’s lifespan. We emphasize issues faced by specific groups, including neonates and females of reproductive age experiencing abnormal uterine bleeding and postpartum hemorrhage. Elderly patients present unique challenges and concerns related to the management of bleeding as well as thrombotic complications. The current assortment of diagnostic laboratory assays shows limited success in predicting bleeding risk in the peri-surgical setting of patients with FXI deficiency. This review explores the intricate interplay between individual bleeding profiles, surgical sites, and FXI activity levels. We also evaluate the accuracy of existing laboratory assays in predicting bleeding and discuss the potential role of investigational global assays in peri-operative assessment. Furthermore, we outline our suggested diagnostic approach to refine treatment strategies and decision-making. Available treatment options are presented, including antifibrinolytics, replacement products, and recombinant FVIIa. Finally, we discuss promising non-replacement therapies for the treatment of rare bleeding disorders that can potentially address the challenges faced when managing FXI deficiency-related bleeding complications.