LAUSR

BACKGROUND Temporal changes in fibrinolytic activity after injury and their impact on outcomes remain poorly defined. We conducted a prospective, multicenter cohort study to determine the incidence of fibrinolytic phenotypes after injury and the trajectories and associated outcomes of these phenotypes over time. METHODS We included adults that arrived within 6 hours of injury to three American Level I trauma centers. Clot lysis at 30 minutes (LY-30) was measured at presentation and at 3 hours, 6 hours, 12 hours, 24 hours, 48 hours, 72 hours, 96 hours, and 120 hours. LY-30 was used to categorize patients into the following fibrinolytic phenotypes: fibrinolysis shutdown (SD, LY-30 ⩽0.8%), physiologic fibrinolysis (PHYS, LY-30 >0.8% to <3%), or hyperfibrinolysis (HF, LY-30 ≥3%). We used multivariable logistic regression to estimate adjusted odds ratios for mortality. RESULTS We included 795 adults (median age, 38 years; median Injury Severity Scale score, 21). In total, 44% presented with SD, 36% with PHYS, and 21% with HF. Mortality was highest among those who presented with HF (20%) followed by SD (10%) and PHYS (7%) (p = 0.001). While mortality within the first 24 hours was highest with admission HF (14% vs. 5% SD vs. 4% PHYS; p = 0.001), both admission HF (7%) and SD (6%) had higher mortality after 24 hours compared with PHYS (3%) (p = 0.04). All patients who presented with HF switched into another phenotype or died within 24 hours. The majority of patients that presented in SD remained in that phenotype, including 71% at 24 hours and 72% at 120 hours. Persistent SD at 24 hours was independently associated with increased mortality after 24 hours (odds ratio, 3.20; 95% confidence interval, 1.51–6.67). CONCLUSION Approximately 70% of major trauma patients who present with SD remain in this phenotype up to 120 hours postinjury. In contrast, patients presenting with HF transition into another phenotype or die within 24 hours. While early mortality is highest with the HF phenotype, persistent SD at 24 hours is associated with elevated late mortality. LEVEL OF EVIDENCE Prognostic and epidemiological study, level II.