Impact of Presenting Physiology and Associated Injuries on Outcome following Traumatic Rupture of the Thoracic Aorta

Abstract

We hypothesized that the predominant factor influencing outcome of traumatic rupture of the thoracic aorta (TRA) was the degree of shock on presentation and associated injuries. We reviewed our experience with TRA over a 15-year period. Patients were classified as "unstable" if presenting systolic blood pressure was <90 mm Hg or if it decreased to <90 mm Hg after admission. We determined the presence of closed head injury, cardiac risk factors, a preoperative acute lung injury (ALI). The influence of these factors on mortality, postoperative adult respiratory distress syndrome (ARDS), and paralysis was analyzed. One hundred thirty-six patients were admitted with TRA. One hundred twenty underwent operative repair with a mortality of 31 per cent. Operative mortality was significantly higher in unstable patients (62%) versus stable patients (17%, P = 0.001), in patients with cardiac risk factors (71%) versus those without (24%, P = 0.001), and in patients with preoperative free rupture (83%) with versus those without (19%, P = 0.001). Free rupture was the cause of hypotension in only 10 of 42 unstable patients, with the remainder being due to other causes. Preoperative ALI was associated with a marked increase in postoperative ARDS (47% with vs 9% without, P = 0.001) but not operative mortality. Mechanical circulatory support (MCS) was used in 59 cases, none of whom experienced paralysis, whereas eight of 61 operated on without MCS developed paralysis (P = 0.001). When logistic regression was applied the use of MCS was not determined to be statistically significant. However, preoperative instability was found to be a significant predictor of postoperative paralysis with the risk being increased 5.5 times (confidence interval 3.3-10). The predominant factor influencing mortality, postoperative ARDS, and paralysis was preoperative instability and associated injuries. In patients who are hypotensive, other injuries should take precedence over repair of TRA. Patients who are stable but who have cardiac or pulmonary risk factors may be better managed by a period of nonoperative management until their condition improves.