National trauma databank analysis of mortality and limb loss in isolated lower extremity vascular trauma.

OBJECTIVES: Lower extremity injury is common in trauma patients; however, the influence of arterial injury on devastating patient and limb outcomes can be confounded by the presence and physiological derangement of concomitant head or thoracoabdominal injuries. We analyzed isolated lower extremity injuries with an arterial component. Our aim was to elucidate factors associated with mortality and limb loss in this selected population.

METHODS: We reviewed trauma incidents from the National Trauma Data Bank (2002-2006) containing isolated lower extremity injury codes and a specified infrainguinal arterial injury. Demographics, injury patterns, clinical characteristics, and adverse outcomes (death, amputation) during initial hospitalization were collected. Multivariate logistic regression was used to identify risk factors for limb loss.

RESULTS: There were 651 isolated infrainguinal arterial injuries. Death (18) and early limb loss (42) were studied by mechanism (penetrating, n = 431; blunt, n = 220). Half of the deaths involved injury to the common femoral artery (CFA), and over 80% had injury to the CFA or superficial femoral artery (SFA). Death was three times as frequent in the CFA/SFA than in the popliteal/tibial injuries (P = .02). Penetrating injuries were present in almost 80% of deaths, and most of these were gunshot wounds. Patients who died had mean initial systolic blood pressure of 59.7 mm Hg, and almost 40% had no blood pressure on arrival. Mean initial Glasgow Coma Score was 4.5, and almost 80% arrived with a Glasgow Coma Score of 3 despite the absence of head injury. Twenty-seven above- and 15 below-the-knee amputations were performed. The popliteal artery was injured in half of the amputations, with injury isolated to the popliteal or tibial arteries in about three-quarters. Amputation was twice as frequent in popliteal/tibial than CFA/SFA injury (P = .03) and twice as frequent in blunt than penetrating injury (P = .05). Multiple arterial injuries (odds ratio, 5.2; 95% confidence interval, 1.7-15.6; P = .003), and fracture (odds ratio, 2.2; 95% confidence interval, 1.1-4.2; P = .02) independently predicted amputation, while the presence of nerve injury and soft tissue disruption did not.

CONCLUSIONS: Isolated lower extremity trauma with vascular injury has a nearly 10% rate of mortality or limb loss. Mortality is associated with penetrating mechanism and early shock, likely resulting from prehospital proximal arterial hemorrhage. In contrast, early limb loss is more common with blunt distal vascular injury, especially to the popliteal and tibial arteries. Neither nerve nor soft tissue injury predicted limb loss but may result in delayed amputations not captured in this acute outcomes dataset.