Injury grade is a predictor of aortic-related death among patients with blunt thoracic aortic injury

Abstract

Objective: The current Society for Vascular Surgery Clinical Practice Guidelines suggest urgent (<24 hours) thoracic endovascular aortic repair for grade (G) II to G IV blunt thoracic aortic injuries (BTAIs). The purpose of this study was to determine whether some patients may require more emergency treatment.

Methods: We reviewed imaging variables of prospectively collected BTAI patients between 1999 and 2014. We used computed tomographic angiography to classify BTAIs into four categories: G I, intimal tear; G II, intramural hematoma; G III, aortic pseudoaneurysm; and G IV, free rupture. Specific examination of G III injuries was undertaken in an effort to predict aortic-related mortality (ARM) before repair. For this subset, we examined pseudoaneurysm size, lesion/normal aortic diameter ratio, and mediastinal hematoma location and size.

Results: Among 331 patients with BTAIs, 86 died before imaging. Admission computed tomographic angiography was available for 205 patients (71.2% male; mean age, 39.3 years) with BTAIs (24 G I, 49 G II, 124 G III, 8 G IV). The mean Injury Severity Score was 35.6, and 22.4% had hypotension (<90 mm Hg). Overall mortality was 11.2% (G I/G II, 4.1%; G III/G IV, 15.3%; P = .02). ARM was 2.4% (G I/G II, 0%; G III/G IV, 3.8%; P = .09). ARM was significantly greater in G IV (3 of 8 [37.5%]) than G III (2 of 124 [1.6%]) vs G I/II (0 of 73 [0%]) injuries (P < .0001). Medical management alone was used in 53 (20 G I, 18 G II, 13 G III, and 2 G IV). Open repair was performed in 51 (3 G I, 9 G II, 36 G III, and 3 G IV) at a mean time to repair (TTR) of 10.6 hours. Thoracic endovascular aortic repair was conducted for 101 patients (1 G I, 22 G II, 75 G III, and 3 G IV) at a mean TTR of 9.4 hours. Median TTR for the overall population of BTAI patients was 24.0 hours from admission. (G I, 64.5 hours; G II, 24.0 hours; G III, 19.7 hours; and G IV, 3.5 hours). ARM occurred in four of five patients before planned repair (2 G III and 2 G IV), 7.0 ± 3.6 hours from admission. No G I/II ARM occurred. Among eight G IV injuries, there were three ARMs. Focus on G III injuries through regression analysis demonstrated that early clinical/imaging variables (eg, mediastinal hematoma dimensions and lesion/normal aortic diameter ratio) were not significant predictors of ARM.

Conclusions: Injury grade is a predictor of ARM among patients with BTAIs. Aggressive use of the current Society for Vascular Surgery Clinical Practice Guidelines at a busy level I trauma center resulted in low rates of ARM. In this setting, identification of additional physiologic and radiographic criteria indicating the need for emergency (vs urgent) repair of aortic pseudoaneurysms remains elusive.