The Role of CT Angiography in Evaluating Lower Extremity Trauma: 157 Patient Case Series at a Military Treatment Facility.

Abstract

Physical exam and angiography have important roles in the diagnosis of traumatic lower extremity vascular injury with similar reported high rates of sensitivity and specificity. It has been previously shown that CTA is not universally indicated in the setting of acute lower extremity trauma when a reliable physical examination is obtained. As such, the purpose of this study was to determine if obtaining a CTA following physical examination altered the clinical care of patients following high-energy lower extremity trauma and the generalizability to the military population. Retrospective review of all patients who underwent lower extremity CTA during the initial trauma evaluation at a Level 1 Trauma Center from 2007 to 2014. One hundred and fifty-seven patients met inclusion criteria. One hundred and seventeen patient's initial physical exam excluded limb ischemia with 67 vascular injuries on CTA (9 underwent angiogram in the OR) with no reperfusions required. 40 patients had hard signs of ischemia or ABI's <0.90, 29 had injuries on CTA, and fifteen underwent a vascular reperfusion procedure for acute vascular injury. Ten of 15 reperfusions required no further angiography after CTA. The sensitivity and negative predictive value of physical exam for needed reperfusion were both 100%. There were no instances of missed vascular injury or readmission and 53 patients were discharged directly from the emergency room after a negative CTA. This study suggests that physical exam alone achieves a high sensitivity for vascular injury in lower extremity trauma. Physical exam excluded all lower extremity ischemia without the need for advanced imaging. While CTA was useful to confirm and localize the source of acute vascular injury, the majority of vascular injuries identified on CTA did not affect immediate clinical care and lead to additional unnecessary procedures. However, in patients with suspected vascular injury, a negative CTA was also used as rationale for immediate discharge from the emergency department without further clinical observation. When applied to the deployed military setting the results of this study support the use of physical exam to accurately diagnose limb threatening ischemia at the time of injury or Role 1 facilities with CTA reserved for diagnosing the level of the vascular injury and for potential patient clearance prior to prolonged evacuation.