The role of the ankle brachial pressure index in the diagnosis of peripheral arterial injury.

Background: Angiography is the "gold standard" diagnostic tool for patients presenting soft signs of arterial injury. To reduce the number of unnecessary angiographies, we aimed to evaluate the role of the ankle brachial pressure index (ABPI) in the diagnosis of peripheral arterial injury in extremity trauma with soft signs.

Methods: The data of 1772 patients with the suspicion of peripheral arterial injury was recorded prospectively. Two hundred eighty-three patients (16%) with any hard sign underwent immediate surgery. ABPI was calculated in 1489 patients with soft signs. Patients with ABPI <1 were evaluated by duplex ultrasonography and/or angiography, and if arterial injury was detected, the patients underwent surgery. Patients with an ABPI > or =1 were followed up conservatively.

Results: 1343 (90%) patients had ABPI > or =1; seven (0.5%) of them developed symptoms and signs of arterial injury and healed without morbidity. One hundred forty-six (10%) patients had ABPI <1; with DUS/angiography, arterial injury was detected in 39 of them (26.7%), and they underwent surgery. The sensitivity of ABPI <1 was 84.8%; specificity 92.6%; positive predictive value 26.7%; negative predictive value 99.5%; and overall accuracy 92.3%.

Conclusion: ABPI excludes arterial injury in 99.5% of patients with soft signs of arterial injury and avoids unnecessary examinations in 90% of patients. In the management of extremities with soft signs, ABPI measurement should be the first-line diagnostic choice.