Yield of CT angiography in penetrating lower extremity trauma.

PURPOSE: CT angiography (CTA) has become a valuable tool in the assessment of suspected arterial injury in patients with penetrating lower extremity trauma. However, expensive imaging such as CTA should be judiciously utilized to ensure value-based care. We therefore assessed the yield of CTA in this setting at a level-1 trauma unit and correlated it with the clinical history provided. METHODS: A retrospective descriptive study from 1 July 2013 to 31 June 2018 at a 1386-bed, tertiary-level, public-sector teaching hospital in Cape Town, South Africa.. All patients undergoing CTA for suspected arterial injury following penetrating lower extremity trauma were included. The imaging yield of clinically significant arterial injury and the predictive value of specific clinical signs were determined. RESULTS: A total of 983 patients (median age 27 years, 91% male) were included; 90% (886/983) had gunshots, 9% (89/983) stabs, and 1% (8/983) other injuries. Despite an average 13% year-on-year increase in CTA performed, there was no change in the proportion demonstrating arterial injury. Thirty-four percent (23/68) of patients with strong (hard) signs of arterial injury (active pulsatile bleeding, rapidly expanding hematoma, absent pulse, palpable thrill, or audible bruit), 11% (49/459) with moderate (soft) signs (history of an arterial bleed, excessive non-pulsatile bleeding, large non-expanding hematoma, major neurological deficit, diminished but appreciable pulse, and arterial proximity), and 5% (24/456) with no indication for imaging had clinically significant arterial injuries. Significant positive correlations were rapidly expanding hematoma (p = 0.009), an absent pulse (p < 0.001), and a diminished pulse (p < 0.001). Significant negative correlations were proximity to a major artery (p = 0.005) and no clinical indication provided (p < 0.001). CONCLUSION: There is poor correlation between clinical details provided and the presence of arterial injury at our institution. In this context, CTA serves a pivotal role in the definitive identification of arterial injury.