Approach Considerations
In general, hard signs of injury (eg, a change in pulse quality compared to the opposite extremity or a loss of pulse in the extremity) are absolute indications for further diagnostic studies (eg, arteriography or exploration and direct visualization in the operating room). Softer signs (eg, temperature change, color change, delayed capillary refill, or neurologic deficit) should alert the clinician to the need for close observation and monitoring.
If the ankle-brachial index (ABI) is higher than 0.9, many authors advocate observation, but if the ABI is lower than 0.9, further evaluation is warranted. In these cases, many authors now recommend duplex Doppler vascular studies as a rapid, noninvasive method of assessing vascular injury. However, an arteriogram in stable patients and operative exploration in unstable or bleeding patients remain the criterion standards of care.
Preexisting renal insufficiency and allergies (eg, to seafood, iodine, or contrast dye) are relative contraindications for arteriography in the assessment of vascular injury of an extremity. Preangiography volume resuscitation and sodium bicarbonate may help minimize complications.
Persistent massive hemorrhage and hemodynamic instability are the principal contraindications for any diagnostic studies, and patients with these conditions require urgent operative exploration for diagnostic and therapeutic measures. Duplex Doppler studies may provide important information regarding vascular injury in most stable patients who have contraindications to arteriography.
Laboratory Studies
Baseline blood work should consist of a complete blood count (CBC) with platelet count, electrolytes, blood urea nitrogen (BUN), and creatinine evaluations.
Typing and crossmatching of packed red blood cells for 4-8 units, depending on the severity of injury and hemorrhage, is also recommended.
Prothrombin time (PT) and activated partial thromboplastin time (aPTT) may be helpful in patients who are comatose and unable to provide an adequate medical history, though statistically, findings are rarely abnormal when the medical history documents no medications (eg, warfarin) or a history of bleeding problems.
In acute hemorrhage without equilibration, remember that the hematocrit or hemoglobin level may appear to be within the laboratory reference range even though there may be a significant cellular volume loss.
Imaging Studies
Plain radiography
Plain radiography of the injured extremity is a rapid means of determining the presence of fractured bones and foreign bodies. Certain fractures (eg, supracondylar femur fractures) have a higher incidence of vascular injuries, and recognition of these types of injuries alerts the clinician to the risk of vascular injury.
Computed tomography
Computed tomography (CT) has long been used in extremity trauma to visualize bony anatomy and soft tissues. Several studies found multidetector CT angiography (MDCTA) to be a useful modality for assessing lower-extremity vascular injuries. [26, 27, 28] This modality is considered to be the first-line investigation for evaluating the extremities in vascular emergencies. [29]
Angiography
Arteriography in the angiography suite is reserved for patients who are hemodynamically stable and preferably are not experiencing renal failure or insufficiency. Most interventional radiologists require preprocedural BUN and creatinine measurements before proceeding with these studies. As soon as is practicable, blood for these assays should be drawn in the resuscitation area to avoid delays in angiography, which may lead to delays in operative intervention.
In many cases, the surgeon can perform on-table angiography in the operating room with minimal risk to the patient. Surgeons should be familiar with arterial access points and the contrast materials available in their institution. Knowledge of total dye load and baseline renal status minimizes complications in this situation.
Duplex ultrasonography
Duplex Doppler ultrasonography (US) of injured extremities has proved to be a viable alternative to angiography in many centers. This study can be performed by the surgeon in the emergency department or in the resuscitation bay and can provide immediate and valuable information regarding patient vascular status or injury. Duplex Doppler US may be of limited use in patients with splints, extensive orthopedic hardware, or areas of large tissue and skin loss, as well as when it is performed by inexperienced personnel. Johansen et al offer a more detailed discussion of noninvasive tests in a screening situation. [30]
Other Tests
Measurement of the ABI is useful with atherosclerotic peripheral vascular disease and may be helpful in determining vascular insufficiency, but ABI cannot localize the site of injury. Measurement of the ABI is a helpful component of the evaluation of penetrating arterial injury, but again, the ABI will not be able to localize the site of injury.
A prospective study by Lynch and Johansen [31] suggested that measurement of the ABI approaches the accuracy of arteriography in identifying arterial injuries and, more important, accurately identifies injuries needing intervention. Nassoura et al supported this finding in a subsequent prospective trial. [32] No diagnostic test is perfect; nevertheless, measurement of the ABI offers a noninvasive, simple, and reproducible method to accurately screen for penetrating arterial injury.
Algorithms for the management of blunt lower-extremity trauma have recommended additional imaging in patients presenting with soft signs of vascular injury and an ABI below 0.9. A single-center retrospective review by Hemingway et al (N = 125; 133 injured limbs) suggested that a lower ABI threshold (0.6) in these patients might avoid unnecessary imaging without missing vascular injuries requiring intervention. [33] Further prospective studies are needed to validate the safety and effectiveness of a lower ABI threshold.
Assessing for a Doppler signal in peripheral vessels is more sensitive than manual palpation and is helpful in assessing for total occlusion or transection of the arterial tree.
Staging
Organ injury scaling may be helpful in the acute setting but should not override clinical experience and individual patient needs. Vascular injury scaling is also helpful for epidemiological study, peer review, and coding and billing. For information regarding organ injury scaling of peripheral vascular injuries currently sanctioned by the American Association for the Surgery of Trauma, see the study by Moore et al. [34]
The Mangled Extremity Severity Score (MESS) is an objective criterion for amputation prediction after lower- or upper-extremity injury. A MESS of 7 or higher has been used as a cutoff point for amputation prediction.
Prichayudh et al examined the result of upper-extremity vascular injury management and amputation rate as related to MESS in 52 patients. [35] Seven patients underwent amputation (overall amputation rate, 13.46%). On multivariate analysis, the only factor significantly associated with amputation was the MESS. No amputations were performed in 33 patients who had a MESS lower than 7. Secondary amputations (amputation after primary operation) were done in four of 49 patients (8.16%). All amputation patients suffered blunt injuries and had a MESS of 7 or higher (range, 7-11). Amputation was avoided in 12 of 19 patients who had a MESS of 7 or higher.
A MESS of 7 or higher does not always indicate that amputation is required; however, MESS is a better predictor for patients who do not require amputation when the score is below 7. The decision regarding whether or not to amputate should be made individually on the basis of clinical signs and intraoperative findings of irreversible limb ischemia.
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Crushed and mangled foot of a person who was involved in a motor vehicle accident.
