Delayed splenic pseudoaneurysm identification with surveillance imaging.

BACKGROUND: Recent studies have shown that nonoperative management of patients with splenic injury has up to a 90% success rate. However, delayed hemorrhage secondary to splenic artery pseudoaneurysm occurs in 5% to 10% of patients with up to 27% of patients developing a pseudoaneurysm on delayed imaging. The goal of our study was to evaluate the safety and utility of delayed computed tomography (CT) imaging for blunt splenic injury patients. METHODS: A retrospective evaluation of all traumatic splenic injuries from 2018 to 2020 at a single level 1 trauma center was undertaken. Patients were subdivided into four groups based on the extent of splenic injury: grades I and II, grade III, grade IV, and grade V. Patient injury characteristics along with hospital length of stay, imaging, procedures, and presence/absence of pseudoaneurysm were documented. RESULTS: A total of 588 trauma patients were initially included for evaluation, with 539 included for final analysis. Two hundred ninety-seven patients sustained grades I and II; 123 patients, grade III; 61 patients, grade IV; and 58 patients, grade V splenic injuries. One hundred twenty-nine patients (24%) underwent either emergent or delayed (>6 hours) splenectomy with an additional six patients having a splenorrhaphy on initial operation. Of the patients who were treated nonoperatively, 98% of grade III, 91% of grade IV, and 100% of grade V splenic injury patients underwent follow-up CT imaging. The mean ± SD time from admission to follow-up abdominal CT scan was 5 ± 4.4 days. Twenty-two pseudoaneurysms were identified including grade III (10 of 84), grade IV (7 of 22), and grade V (2 of 5) patients; of these patients, 33% of grade III and 30% of grade IV required subsequent splenectomy. CONCLUSION: Routine follow-up CT imaging after high-grade splenic injury identifies splenic artery pseudoaneurysm in a significant proportion of patients. Standardized surveillance imaging for high-grade splenic trauma promotes prospective identification of pseudoaneurysms, allowing for interventions to minimize delayed splenic injury complications. LEVEL OF EVIDENCE: Therapeutic/Care Management; level IV.

Effect of a dalteparin prophylaxis protocol using anti-factor Xa concentrations on venous thromboembolism in high-risk trauma patients.

BACKGROUND: Low anti-factor Xa (anti-Xa) concentrations with twice-daily enoxaparin are associated with venous thromboembolism (VTE) in high-risk trauma patients. Concerns have been raised with once-daily dalteparin regarding effectiveness and achievable anti-Xa concentrations. The purpose of this before-and-after study was to evaluate the effectiveness of a VTE prophylaxis protocol using anti-Xa concentrations and associated dalteparin dose adjustment in high-risk trauma patients. METHODS: Adult trauma patients receiving VTE chemoprophylaxis and hospitalized for at least 3 days were prospectively followed during two 6-month epochs before (PRE) and after (POST) implementation of anti-Xa monitoring. In both groups, high-risk patients received dalteparin 5,000 U subcutaneously once daily; low-risk patients received subcutaneous unfractionated heparin. High-risk POST patients with anti-Xa less than 0.1 IU/mL 12 hours after initial dalteparin dose received dalteparin every 12 hours. All patients underwent routine VTE ultrasound surveillance of the lower extremities. The primary outcome was incidence of VTE. RESULTS: A total of 785 patients (PRE, n = 428; POST, n = 357) were included. Demographics, injury patterns, Injury Severity Score (ISS), red blood cell transfusions, intensive care unit and hospital stays, and mortality did not differ between groups. Overall, POST patients had lower VTE (7.0% vs. 13%, p = 0.009) including acute VTE (6.4% vs. 12%, p = 0.01) and proximal deep vein thromboembolism (2.2% vs. 5.7%, p = 0.019). Between high-risk patients, VTE occurred in 53 (16.3%) PRE compared with 24 (9.0%) POST patients (p = 0.01); there was no difference in VTE between low-risk patients (PRE, 2.0% vs. POST, 1.1%; p = 0.86). Among 190 high-risk POST patients with anti-Xa, 97 (51%) were less than 0.1 IU/mL. Patients with low anti-Xa had higher rates of VTE (14.0% vs. 5.4%, p = 0.05) and deep vein thromboembolism (14.4% vs. 3.2%, p = 0.01). Younger age (odds ratio, 0.97; 95% confidence interval, 0.95-0.99) and greater weight (odds ratio, 1.02; 95% confidence interval, 1.00-1.03) predicted low anti-Xa on multivariate regression. CONCLUSION: A VTE prophylaxis protocol using anti-Xa-based dalteparin dosage adjustment in high-risk trauma patients was associated with decreased VTE. Once-daily dalteparin 12-hour anti-Xa concentrations are suboptimal in a majority of patients and associated with VTE. LEVEL OF EVIDENCE: Therapeutic study, level IV.