A retrospective study of the prevalence of isolated prolongation of activated partial thromboplastin time in the preoperative setting

BACKGROUND: Isolated prolongation of activated partial thromboplastin time (APTT) has various causes including inheritable bleeding disorders, and has medical significance as it can lead to the cancelation of surgery. However, even an emergency surgery can be conducted in a patient presenting with severe APTT prolongation, provided careful evaluation and appropriate measures are taken. Hence, the identification of the underlying etiology of the prolonged APTT is crucial. To date, little evidence exists regarding the prevalence of isolated APTT prolongation in Japanese patients undergoing surgery. Herein, we aimed to clarify the prevalence of isolated prolongation of APTT in the preoperative setting and to identify the reasons underlying isolated, severely prolonged APTT. METHODS: Preoperative coagulation data of all elective and emergent patients who presented to the anesthetic department between January 1, 2020, and June 30, 2023, were retrospectively collected. Isolated prolongation of APTT was defined as an APTT ≥ 37 s with an international normalized ratio of prothrombin time < 1.2. The underlying etiology of the patient with isolated, severely prolonged APTT (≥ 46 s) was investigated, and canceled surgical procedures in relation to the isolated APTT prolongation were searched. RESULTS: Overall, 10,684 measurements from 9413 patients were included, of which 725 (6.8%) were identified as having isolated APTT prolongation. The reasons for the severely prolonged APTT (n = 60) were miscellaneous, with the most frequently detected etiology being antiphospholipid antibody positivity. Preoperative isolated APTT prolongation contributed to the cancellation of surgery in elective five cases. CONCLUSIONS: We clarified the prevalence of preoperative isolated prolongation of APTT. The presence of antiphospholipid antibody was the most frequently detected etiology of the patient with isolated, severely prolonged APTT. The present study provides an important dataset regarding the isolated prolongation of APTT in East Asian patients undergoing surgery.