PO149 | MANAGEMENT OF ANTITHROMBOTIC THERAPY IN A PATIENT WITH HEMOPHILIA C AND ATRIAL FIBRILLATION

E. Marrone¹, G. Ruggiero², E. Cimino³, P. Conca³, C. Miele⁴, F. Gallucci¹, A. Abate¹, C. Romano¹, D. Leosco², U. Valentino¹ | ¹Department of Medicine 3, Cardarelli Hospital, Napoli, Italy; ²School of Specialization in Geriatrics; ³Department of Internal Medicine and Blood Coagulation; ⁴Department of Laboratory Medicine and Transfusion, Federico II University, Napoli, Italy

Background. Factor XI (FXI) deficiency, also known as hemophilia C, is a rare, autosomal recessive inherited coagulopathy first described in the 1950s. Prevalence in the general population is estimated at around 1 in 1 million. The most common manifestations include prolonged bleeding after trauma or surgery, frequent nosebleeds, easy bruising, bleeding gums, and, in women, menorrhagia and prolonged postpartum bleeding. The management of patients with FXI deficiency presents several critical clinical challenges; elderly patients, in particular, face challenges related to the management of both bleeding and thrombotic complications.
Case Report. We describe the clinical case of an 85-year-old male patient with new-onset arrhythmia and concomitant diagnosis of congenital FXI deficiency. The patient, with a medical history of Parkinson’s disease, was initially admitted to the Emergency Department for dyspnea secondary to pneumonia. During hospitalization, the patient developed new-onset atrial fibrillation with a high ventricular rate, up to 150 bpm. He was initially treated with beta-blockers for rate control, but he soon experienced severe episodes of sinus bradycardia, with his heart rate dropping to 37 bpm. Consequently, beta-blocker therapy was immediately discontinued. Holter monitoring subsequently confirmed a diagnosis of tachycardia-bradycardia syndrome. He was therefore designated a priority candidate for permanent pacemaker implantation (PPM). Laboratory tests revealed an isolated prolongation of the activated partial thromboplastin time (aPTT). Specific hematological analyses ruled out the presence of LAC and factors IX or VIII deficiency, but confirmed a diagnosis of congenital FXI deficiency, with FXI levels measured at 10% and 22% in two separate samples. The clinical management of this patient presents a significant dilemma: balancing cardioembolic and hemorrhagic risks both in anticipation of permanent pacemaker (PPM) implantation and in the long term. In preparation for the planned implantation of a PPM, a multidisciplinary hemostatic plan is established. To manage FXI deficiency, the patient receives perioperative replacement therapy with fresh frozen plasma via continuous infusion. This treatment begins 24 hours before surgery and continues postoperatively to ensure stable hemostasis while the surgical wound heals. For long-term stroke prevention, the strategy focuses on balancing the predominant cardioembolic risk with the patient's general frailty and risk of falls. After a brief period of prophylactic heparin suspension prior to surgery, the patient receives reduced-intensity direct oral anticoagulant (DOAC) therapy. Additionally, percutaneous left atrial appendage closure (LAAC) is considered a strategic alternative in case future complications or frailty make pharmacological anticoagulation unsustainable.
Conclusions. This case highlights the crucial importance of maintaining a high index of clinical suspicion and focusing on the management of rare conditions, such as factor XI deficiency, especially when they coexist with common comorbidities such as atrial fibrillation. Although the current strategy favors a personalized DOAC regimen, the LAAC as a future safety measure allows the treatment plan to remain adaptable to the patient's evolving needs. However, further data from larger patient groups will be useful to better define the long-term outcomes and safety of this integrated approach.