Perioperative prothrombin time activity trajectories and subsequent mortality after surgical repair of acute type A aortic dissection

Background Perioperative prothrombin time activity (PTA) changes rapidly during surgical repair of acute type A aortic dissection (ATAAD), but single measurements do not capture heterogeneous longitudinal patterns. We sought to identify recurring perioperative PTA trajectories, characterize their clinical context, and examine their association with subsequent all-cause mortality. Methods This single-center retrospective cohort included 284 adults who underwent ATAAD repair from 2021 through 2023. Group-based trajectory modeling used the last preoperative and observed postoperative day (POD) 1–7 PTA measurements. Patients required at least three observed PTA measurements for trajectory modeling. Mortality analyses began immediately after POD7. The primary Cox model adjusted for age and sex; Firth regression addressed sparse events. Incremental information beyond last preoperative PTA was evaluated by a prespecified likelihood-ratio comparison. Results The trajectory cohort comprised 268 patients with 1,895 observations and 27 deaths after POD7. Four perioperative PTA trajectory groups were identified: moderate-stable [87 (32.5%)], low-declining [50 (18.7%)], preserved-rapidly-declining [61 (22.8%)], and high-preserved [70 (26.1%)]. Cumulative mortality differed globally (log-rank P = 0.00210), and trajectory group remained associated with subsequent mortality in the age- and sex-adjusted Cox model (global P = 0.0322) and Firth sensitivity analysis (global P = 0.0481). The prespecified direct low-declining-versus-preserved-rapidly-declining comparison did not demonstrate a clear difference. Adding trajectory group to age, sex, and last preoperative PTA did not show clear incremental information (likelihood-ratio P = 0.304; Firth P = 0.380). After exclusion of mechanical-valve recipients, the principal trajectory structure was largely preserved, although this sensitivity analysis did not exclude treatment-related effects on PTA. Conclusion Four reproducible perioperative PTA trajectories characterized distinct longitudinal patterns and were associated with mortality after the POD7 landmark. These trajectories should be interpreted as composite perioperative patterns reflecting both disease and treatment context rather than as intrinsic coagulation states. They were not ordered mortality-risk tiers and did not show clear incremental prognostic information beyond last preoperative PTA. External validation is required.