Factor V Deficiency and Mechanical Valve Replacement: Challenges in Perioperative Hemostasis and Anticoagulation.

Factor V deficiency is a rare autosomal recessive bleeding disorder marked by impaired thrombin generation and variable bleeding risk. Perioperative management becomes particularly challenging in high-risk surgeries, such as aortic valve replacement, due to the absence of targeted replacement therapies and the limited efficacy of fresh frozen plasma (FFP) in restoring factor V levels. We report the case of a 30-year-old woman with congenital factor V deficiency (baseline activity 18%) who underwent successful mechanical aortic valve replacement and mitral valve repair for infective endocarditis. She received preoperative FFP aiming for a factor V level >20%. Her perioperative management included careful monitoring with a total of 23 units of FFP administered. Despite persistently low postoperative f levels (<20%), she experienced minimal bleeding complications, limited to transient anemia and one episode of gross hematuria requiring platelet transfusion. Outpatient follow-up revealed heterozygosity for both factor V Leiden and a prekallikrein variant, potentially explaining her relatively mild bleeding phenotype. This case highlights the disconnect that may exist between laboratory values and clinical bleeding risk, emphasizing the need for individualized perioperative planning and cautious anticoagulation management.