Temporal Coagulation Biomarker Profiles After Andexanet Alfa Use for Procedure‐Related Cardiac Tamponade

Introduction Procedure‐related cardiac tamponade remains a serious complication of invasive arrhythmia procedures. Although andexanet alfa has been used for refractory pericardial bleeding in patients receiving factor Xa inhibitors, little is known about temporal changes in coagulation biomarkers after its administration in this setting. Methods and Results We conducted a single‐center retrospective observational study of 15 patients with cardiac tamponade secondary to procedure‐related cardiac injury between January 2019 and December 2025. Patients were classified according to andexanet alfa use during tamponade management. Coagulation parameters were evaluated at predefined time points from before tamponade onset through day three. Analyses were primarily descriptive. Of the 15 patients, four were treated with andexanet alfa and 11 were managed without andexanet alfa. All patients in the andexanet alfa group were receiving edoxaban for atrial fibrillation. Hemostasis was achieved in all patients after andexanet alfa administration. Patients treated with andexanet alfa showed a distinctive temporal biomarker pattern, characterized by a more pronounced rise in thrombin‐antithrombin complex and prothrombin fragment 1 + 2 at the early post‐hemostasis time point, whereas D‐dimer showed little apparent change at this time point and appeared to be higher on day one. No thromboembolic complications occurred in the andexanet alfa group during hospitalization. Conclusion In this small descriptive cohort, andexanet alfa administration was followed by prompt hemostasis in all treated patients, while also being accompanied by early increases in thrombin‐generation markers and later evidence of fibrin turnover. These hypothesis‐generating findings support careful use of andexanet alfa as rescue therapy with attention to potential early procoagulant changes.