Peripheral vascular injuries may result from penetrating or blunt trauma to the extremities. If not recognized and treated rapidly, injuries to major arteries, veins, and nerves may have disastrous consequences resulting in the loss of life and limb.
See Medscape's Vascular Surgery Resource Center and Trauma Resource Center for related information.
In the upper extremity, the areas of greatest concern include the axilla and the area from the deltopectoral groove distally across the elbow to the proximal forearm. The axilla, medial and anterior upper arm, and antecubital fossa particularly are considered high-risk areas because of the superficial location of the axillary and brachial arteries in these regions.[1, 2]
Wounds distal to the bifurcation of the brachial artery are less likely to result in serious limb ischemia, as long as either the ulnar or radial artery remains intact. Injuries to a single distal artery can often be managed by ligation alone if the palmar arches are complete and no prior injury is present. This is the case in 95% of these patients.
In the lower extremity, the area of greatest concern extends from the top of the leg marked by the inguinal ligament anteriorly and by the inferior gluteal fold posteriorly, across the knee inferiorly to the level of the mid calf. The inguinal region, medial thigh, and popliteal fossa particularly are considered high-risk locations.[3, 4]
Below the knee, the popliteal artery trifurcates to form the anterior and posterior tibial arteries and the peroneal artery. Arterial wounds affecting a single vessel distal to the trifurcation are unlikely to produce serious limb ischemia. If distal collateralization is adequate, injuries to a single branch may therefore be managed by ligation.
The highest risk of serious vascular injury is associated with high-energy gunshot wounds such as those produced by military rifles and shotguns. Explosives are a frequent cause of vascular injury in military combat. The rate of vascular injury in modern combat (ie, the wars in Iraq and Afghanistan) is 5 times greater than in the past.[5] Blunt and penetrating trauma resulting in extremity fractures also have a high incidence of concomitant vascular injuries, even in the absence of clinical signs. The likelihood of serious vascular injury is lower in patients who sustain low-energy wounds such as those produced by handguns and knives.
Peripheral injuries account for 80% of all cases of vascular trauma. The lower extremities are involved in two thirds of all patients with vascular injuries.
Penetrating trauma accounts for 70-90% of vascular injuries. In the past, iatrogenic injuries related to endovascular procedures accounted for less than 10% of all cases. This percentage is increasing due to the growing use of endovascular procedures for diagnostic and therapeutic purposes.
Mortality/Morbidity
Death due solely to peripheral vascular injuries is uncommon, but does occur due to exsanguination or development of a necrotizing myofascial infection. Major venous injuries accompany 13-51% of significant arterial injuries.
Compartment syndrome may result from ischemia of a muscle compartment. Limb survival is threatened by delays in diagnosis and treatment, particularly when limb perfusion is compromised for more than 6 hours at body temperature ("warm" ischemia).
Extensive concurrent musculoskeletal, nerve, and skin injuries indicate a poor prognosis. Concomitant peripheral nerve injuries may be missed and can lead to long-term disability and deformity.[6]
Crush injuries associated with open tibial fractures are particularly likely to result in loss of the lower leg and amputation.
Sex
Ninety percent of patients with peripheral vascular injuries are male.
Age
Vascular injuries most often occur in patients aged 20-40 years.
In peripheral vascular injury, the mechanism is an important prognostic factor. Shotgun and military rifle injuries, as well as knee dislocations, are particularly high risk for vascular injury.
The time interval between injury and evaluation must be considered. "Warm" ischemia at body temperature for more than 6 hours results in irreversible nerve and muscle damage in 10% of patients. Cooling the extremity may avoid this complication.
Other risk factors include previous history of vascular injury or disease, extensive or pulsatile external hemorrhage, anticoagulation therapy or impaired hemostatic function, and prior venous thrombosis or embolism in the patient or a family member.
Deciding whether the injury requires surgical intervention is a major priority of initial management.
The presence of "hard" signs of vascular injury has a 92-95% sensitivity for injuries requiring intervention. The vast majority of patients exhibiting the following "hard" signs require intervention with a positive predictive value of 95%.
Bruit or thrill: These are present in only 45% of patients with an arteriovenous fistula
Active or pulsatile hemorrhage
Pulsatile or expanding hematoma
Signs of limb ischemia and elevated compartment pressure including the 5 "P's:" Pallor, paresthesias, pulse deficit, paralysis, and pain on passive extension of the compartment." Pain on passive extension is the earliest and most sensitive physical finding.
Diminished or absent pulses: This is not a sensitive prognostic finding, as up to 25% of patients with major vascular injuries requiring repair have normal pulses distal to the injury.
The following "soft" signs are much less useful in predicting or excluding major vascular injuries that require intervention. The positive predictive value of "soft" signs indicating abnormal findings on an arteriogram is only 35%. The vast majority of these lesions do not require emergent repair.
Hypotension or shock
Neurologic deficit due to primary nerve injury occurs immediately after injury. In contrast, ischemic neuropathy is delayed in onset, developing within minutes to hours after injury.
Stable, nonpulsatile or small hematoma
Proximity of the wound to major vascular structures
Causes of peripheral vascular injuries include the following:
Gunshot wounds, particularly high-energy rifle and close-range shotgun wounds, cause 70-80% of all vascular injuries that require intervention.
Stab wounds - Only 5-10% of cases require intervention.
Blunt trauma accounts for 5-10% of cases. The presence of a fracture or dislocation increases the risk. Blunt injuries are often more severe than penetrating injuries due to trauma to adjacent structures. The risk of eventual limb amputation is higher with blunt mechanisms of injury.
Iatrogenic injury now accounts for more than 10% of cases. Endovascular procedures such as cardiac catheterization and central line placement are the two most common iatrogenic causes of vascular injury that require intervention. The incidence of iatrogenic injuries is growing in concert with the increased utilization of endovascular procedures.
The arterial pressure index is useful in detecting patients with major vascular injury and pulses that appear normal. Systolic blood pressure in the affected extremity is divided by systolic pressure in the contralateral normal extremity. A value of less than 90% is considered abnormal.
The sensitivity of the arterial pressure index for injuries requiring intervention ranges from 75-95%, depending on the circumstances. The arterial pressure index is highly sensitive in ruling out popliteal artery injury in patients with knee dislocation. Most injuries that present with an arterial pressure index greater than 90% heal spontaneously.[7]
The ankle-brachial index is equivalent to the arterial pressure index and may be used when multiple extremity injuries are present. This is calculated by dividing the higher of the systolic dorsalis pedis or posterior tibial artery pressure by the ipsilateral brachial artery pressure.
The Allen test is useful for detecting injuries distal to the brachial artery bifurcation. Persistence of pallor of the hand when the radial artery is manually compressed suggests occlusion of the ulnar artery and vice versa.
Conventional angiography remains the criterion standard for evaluation of vascular injuries in trauma patients.[8, 9] The disadvantages include cost, significant time delay in preparation for the test, and a 0.6% major complication rate. Contrast dye load and renal function are important pre-study considerations. Only 1-1.5% of proximity angiograms performed in patients lacking "hard" signs of vascular injury reveal injuries that require intervention. Duplex ultrasonography is a noninvasive technique used to investigate injuries with a high-risk mechanism or location but without "hard" signs or obvious indications for surgical management.
Small, prospective studies suggest that the sensitivity of ultrasonography is 95-100% for diagnosing vascular injuries that lack "hard" signs but require intervention. These results were obtained by highly qualified teams that maintain a high clinical index of suspicion.[10] Recent studies have found color-flow duplex ultrasonography to be a low-yield strategy for predicting therapeutic intervention.[1] The examination is highly operator dependent, and the negative predictive value has been as low as 50% in some series. Duplex ultrasonography is of limited use in the evaluation of poorly accessible vessels, such as the subclavian, profunda femoris, and profunda brachii arteries. Duplex ultrasonography can play a role in the evaluation of patients presenting with "soft" signs of injury; however, its use has largely been supplanted by multidetector CT angiography.
Multidetector helical CT (MDCT) angiography is emerging as a highly sensitive method of diagnosing arterial injuries when compared with conventional angiography and surgical exploration as criterion standards.[11] Studies using 4- and 16-slice MDCT angiography have demonstrated a sensitivity of 90-95% for significant arterial injuries.[12, 13, 14] . A study by Seamon et al demonstrated a sensitivity and specificity of 100% for clinically significant injury using 16-slice and 64-slice technology.[15]
Higher-resolution (64-slice and greater) MDCT angiography and greater institutional experience will further improve the diagnostic accuracy of the modality. In comparison with conventional angiography, MDCT angiography is considerably faster, less expensive and less invasive, and does not require the involvement of interventional radiology. Studies support MDCT angiography as the diagnostic study of choice for blunt and penetrating vascular trauma patients who have do not have obvious indications for immediate operative intervention.[3]
In a retrospective evaluation of 51 patients with penetrating neck injury, MDCT angiography as initial evaluation was found to help guide management decisions if an external carotid artery injury was detected. Sensitivity of CTA for detecting arterial injuries ranged from 75.7% to 82.2%, and specificity ranged from 96.4% to 98.4%. However, according to the authors, negative findings should not preclude close clinical follow-up, repeat CTA evaluation, or, in the presence of high suspicion of arterial injury due to clinical findings or wound trajectory, evaluation with digital subtraction angiography.[16]
Immediately reduce displaced or angulated fractures if any evidence or suspicion of vascular compromise exists. Promptly reduce dislocations of the elbow and knee to prevent further injury to neurovascular structures.
External hemorrhage usually can be controlled with direct pressure, but a blood pressure cuff or tourniquet should be applied proximally to the injury if compression fails or is not possible.
Once the patient has been stabilized, identify peripheral vascular injuries and restore normal circulation as rapidly as possible.
Do not apply clamps or hemostats to vascular structures, since this may make definitive repair more difficult and damage surrounding tissues.
A vascular surgeon must be consulted whenever a major vascular injury is a concern.
Vascular injury sustained during battlefield combat is often managed via revascularization. Reconstruction methods should be a focus of combat surgery training. Ligation is also an effective intervention.[17]
Low-risk injuries without "hard" or "soft" signs may be managed on an outpatient basis with careful follow-up and a strict schedule for repeat evaluations.
All other patients should be admitted for either definitive repair or further evaluation or observation.
Surgical exploration and repair is performed as soon as possible for patients with "hard" signs of vascular injury, refractory hypotension, and obvious limb ischemia. Conventional arteriography to further define the injury may be performed preoperatively at the discretion of the vascular surgeon. Endovascular repair with stent placement is now used with increased frequency.[18]
Patients with "soft" signs of injury should preferentially be further evaluated by MDCT angiography, or, alternatively by duplex ultrasonography. Certain high-risk injuries, such as shotgun wounds and major vessel proximity injuries, may undergo MDCT or conventional arteriography despite the absence of "hard" or "soft" signs. Low-risk injuries without "hard" and "soft" signs should be observed for possible progression of injury either in the hospital or on an outpatient basis. Major venous injuries of the lower extremities are typically repaired because this improves wound healing and decreases the incidence of compartment syndrome, venous thrombosis, and chronic edema.
Delayed diagnosis and treatment may result in thrombosis, embolization, or rupture with exsanguinating hemorrhage.
Risk factors for amputation include elevated compartment pressure, arterial transection, concomitant open fractures, and the combination of injuries above and below the elbow or knee in the same extremity.[19]
Non-occlusive injuries do not disrupt flow and include the following:
Pseudoaneurysms may resolve completely or grow over time presenting months to years later. They may cause neuropathy due to compression or embolization, and can present as a growing pulsatile mass. See the image below.
View Image
Pseudoaneurysm of the axillary artery.
Arteriovenous fistulae typically take months to mature and often require surgical repair. (See the image below)
View Image
Arteriovenous fistula between common femoral artery and vein.
Intimal tears and flaps generally heal spontaneously over time.
Segmental narrowing can cause diminished flow, but pulses may remain intact. This injury may resolve spontaneously with fluids and rest, or, rarely require surgical intervention.
Approximately 10% of patients with nonocclusive, clinically occult injuries require repair within one month of the initial injury.[20] The remaining 90% of patients do not report symptoms or see a physician for vascular problems during long-term follow-up.[21]
Most non-occlusive injuries presenting without "hard" signs resolve over time.[17] Long-term follow-up with scheduled, repeat physical examinations is a safe and effective approach.
Patients must be given explicit instructions to present for neurovascular checks of the extremities on a scheduled basis. Instruct patients to return to the ED if they experience increased pain, edema, or active bleeding from the wound or if any weakness, numbness, or paresthesias develops in the injured extremity.
Niels K Rathlev, MD, FACEP, Professor and Chair, Department of Emergency Medicine, Tufts University School of Medicine and Baystate Medical Center
Disclosure: Nothing to disclose.
Specialty Editors
Francisco Talavera, PharmD, PhD, Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference
Disclosure: Received salary from Medscape for employment. for: Medscape.
David B Levy, DO, FAAEM, Senior Consultant in Emergency Medicine, Waikato District Health Board, New Zealand; Associate Professor of Emergency Medicine, Northeastern Ohio Universities College of Medicine
Disclosure: Nothing to disclose.
Chief Editor
Trevor John Mills, MD, MPH, Chief of Emergency Medicine, Veterans Affairs Northern California Health Care System; Professor of Emergency Medicine, Department of Emergency Medicine, University of California, Davis, School of Medicine
Disclosure: Nothing to disclose.
Additional Contributors
David A Peak, MD, Associate Residency Director of Harvard Affiliated Emergency Medicine Residency; Attending Physician, Massachusetts General Hospital; Assistant Professor, Harvard Medical School
Disclosure: Partner received salary from Pfizer for employment.
){kind=link}
){kind=link}