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7 • Diagnosis of Vascular Injury 85
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LOWER EXTREMITY VASCULAR INJURIES
Penetrating injuries of the groin and leg produce ndings
Fig. 7.2 Pseudoaneurysm common carotid artery in patient who suffered blunt trauma from striking neck on handle bars of a motorcycle.
He presented to the emergency department complaining of hoarseness. Examination revealed a contusion at the base of the neck and a
bruit over the carotid artery.
similar to the upper extremity with either obvious hemorrhage or distal ischemia.
tures and hip dislocations rarely result in vascular injury,
distal femoral fracture may be associated with supercial femoral arterial injury. The distal supercial femoral
artery and proximal popliteal artery are relatively xed by
the transition through the adductor canal. Stretch injury
and thrombosis may occur. The most common musculoskeletal injury associated with vascular trauma is knee
dislocation.
1,2,10
The popliteal artery is xed proximally by
the adductor canal and distally in the upper calf by the
trifurcation into the anterior tibial, peroneal, and posterior tibial arteries. Posterior displacement of the tibial plateau stretches and disrupts the popliteal artery, resulting
in thrombosis and distal ischemia; and knee dislocation is
associated with as high as a 30% incidence of popliteal vascular injury.
1,3,10
Crush injuries of the lower extremity may cause arterial
disruption at any level. Bumper strike trauma in pedestrians
struck by a motor vehicle are particularly high risk for blunt
vascular injury. Compartment syndrome is also a risk in
this type of injury. All below-knee fractures of the leg must
lead to suspicion of compartment syndrome. However, tibial plateau fracture is the most commonly associated fracture with calf compartment syndrome.
fracture often involve signicant distraction and angulation
of fracture segments with ripping of compartment fascial
planes. An “auto fasciotomy” and decompression of the
compartments often results. Tibial plateau fracture usually
requires signicant force loading but does not result in distraction of fracture segments and the fascial planes remain
2,10
Although proximal femur frac-
3,12
Tibia and bula
Fig. 7.3 (A) CT angiogram coronal reconstruction demonstrating innominate artery pseudoaneurysm in a patient with blunt force compression of the
anterior chest from a high-speed motor vehicle crash. (B) Posterior volume rendering technique view of innominate artery pseudoaneurysm.
A B
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A B
Fig. 7.4 (A) Transiting gunshot wound of volar aspect of the right forearm (outlined by arrow) in patient with distal pulses absent. (B) The patient was
taken directly to the operating room, where the bullet tract was found to transect the brachial artery and both ends were thrombosed and retracted
(arrows). The median nerve was intact.
intact. Intracompartment hemorrhage results with a risk
for compartment syndrome.
OTHER HIGH-RISK INJURY PATTERNS
A high index suspicion for either torso or extremity vascular injury should also attend the evaluation of a variety of
other injuries. High-speed side impacts may be particularly
high risk for thoracic vascular injuries, as well as falls from
signicant height.
9,10
Aircraft crash survivors should all be
evaluated for thoracic aorta and great vessel injuries. Victims of motor vehicle crash with prolonged entrapment
should have careful evaluation for extremity arterial occlusion and compartment syndrome. All crush injuries are
similarly at risk and should prompt a careful evaluation for
the presence of vascular injury.
1,2,10
Physical Examination
Vascular trauma very quickly sorts itself into three major
categories with implications for physician examination and
adjunctive diagnostic measures. First, life-threatening hemorrhage requires immediate action and diagnosis is relatively
quickly made in conjunction with control measures. Second,
limb-threatening arterial occlusive injuries are successfully
diagnosed with an appropriate extremity examination.7 The
third category, occult injuries, is not easily found on physical
examination.
tern recognition of mechanism and associated injuries, are
required to identify these less-than-obvious injuries. There
are commonly described hard and soft signs of vascular
injury which must always be recalled and carefully considered during physical examination (Box 7.2).
The Advance Trauma Life Support guidelines for initial and denitive patient assessment are extremely useful
in the evaluation of patients at risk for vascular injury.5
Acute hemorrhage is addressed during the primary survey.
7,10
Adjunctive measures, often based upon pat-
Box 7.2 Hard and Soft Signs of Vascular Injury
Hard Signs
n Pulsatile hemorrhage
n Expanding hematoma
n Bruit of thrill over area of injury
n Absent extremity pulses
n Injured extremity index <0.9
Soft Signs
n History of hemorrhage
n Wounds of neck or extremities and unexplained hemorrhagic
shock
n Neurologic deficit in peripheral nerve in proximity to vessels
n High-risk fracture, dislocation, or penetrating proximity wound
Life-threatening torso hemorrhage requires immediate operative intervention. Control measures are directly applied to
extremity bleeding, including direct manual pressure and
tourniquet application. Timely operative control and repair
should immediately follow. During the secondary survey, a
thorough physical examination should identify most extremity vascular injuries. In patients with injury mechanisms and
patterns placing them at risk for occult injuries, appropriate
imaging studies should be promptly obtained.
Pulse examination at the wrist and foot must be carefully performed. There is a very common error in “over calling” pedal pulses as present when they are in fact absent.
The doralis pedis and posterior tibial pulses should only be
called present when they are clearly palpable and as easily
found as a normal radial pulse. The “1+ to 2+” pedal pulses
noted in patients with complete proximal arterial occlusion and ischemia are often either palpation of the examiner’s own pulsation in nger tips or simply imagined. The
chain of error that is initiated by calling a pulse present in
error directly threatens limb viability in the presence of a
proximal traumatic arterial occlusion. Conversely, missing
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a pulse that is, in fact, present by calling it absent leads to
further investigation which conrms adequate ow. The
erroneous palpation of pedal pulses in an ischemic limb is
an unfortunately common event. The need for attention to
detail in this portion of the physical examination and the
need for adjunctive measures when there is not a clearly
present pulse are crucial elements of early diagnosis and
successful management of vascular injuries.
7,10,13
The problem of inaccurate pulse examination is pervasive throughout trauma and emergency care.10 Preventing
these errors in diagnosis calls for an organized approach
to the education of the trauma team members, emergency
department staff, critical nursing staff, and medical- surgical
oor staff in the priorities of peripheral vascular examination. This includes not only careful pulse examination,
but also demonstrating the techniques of adjunctive Doppler pressure measurements. This education effort should
be repeated at regular intervals to refresh the knowledge
base of the team members who are essential in recognizing
extremity vascular compromise.
DOPPLER ULTRASOUND ADJUNCTIVE MEASURES
The primary adjunctive measure in the examination of
extremity blood ow is the use of the Doppler ultrasound
and a blood pressure cuff at the wrist or ankle.14 There are
Doppler “myths” that need to be considered. The rst is that
the presence of arterial signals is equal to the presence of
adequate perfusion. The more dangerous myth is that the
presence of Doppler signals indicates the absence of injury.
Although an experienced Doppler ultrasound operator
can identify the triphasic characteristics of a normal patent extremity artery, most physicians and nurses cannot
distinguish the differences between normal and abnormal
Doppler signals. Collateral ow around an occluded artery
may produce Doppler signals of a diminished quality over
the pedal vessels and may be misinterpreted as the absence
of injury.
The only valid use of the Doppler ultrasound in the early
evaluation of the trauma patient for extremity vascular
injury who has distal Doppler signals present is in conjunction with a blood pressure cuff at the wrist or ankle.14 The
Doppler probe is placed over the distal artery and the cuff
slowly inated. The pressure at the cessation of Doppler
signals equals the systolic blood pressure at the cuff, not at
the distal probe. The ankle or wrist pressure is then compared with the other extremity if it is not injured, and to
an uninjured arm. The ratio of the injured extremity distal arterial pressure compared to a normal extremity is the
injured extremity index (IEI) and should be 0.9 or greater.14
Normal ankle–brachial index (ABI) in an uninjured healthy
young person is 1:1.
preting the IEI in patients who are hypotensive, in severe
pain, or hypothermic. Vasoconstriction not associated with
injured vessels may falsely depress the ABI. Reassessment
after resuscitation, adequate pain control, or re-warming
should be performed.
Duplex color ow imaging, although highly accurate, is
not practical for the acute assessment of vascular injury.16
This technology is highly operator dependent and the ability
to obtain satisfactory images is impaired by wounds, hematoma, the presence of air in the tissue, and the presence of
14,15
Caution should be used in inter-
10
dressings.10 However, it is very useful for subsequent outpatient follow-up following vascular reconstruction.
Clearing the Trauma Patient for
the Presence of Vascular Injury
The physical examination has proven valuable in ruling
out spine injuries in stable trauma patients who can be
adequately examined. This process has been dubbed “clearing the spine.” Similarly, physical examination and adjunctive tests can clear each of the major anatomic areas for the
presence of clinically signicant vascular injury. Numerous
studies have proven the value of a normal pulse examination in the extremity without active hemorrhage or hema-
3,7,13,16,17
toma.
a normal extremity neurovascular examination, vascular
injury is not present. Further imaging studies are not needed.
This includes proximity penetrating trauma not associated
with signicant hemorrhage, hematoma, or distal neurologic decit.
major vascular injury in each anatomic area. Further evaluation with imaging studies is reserved for patients who do not
meet the criteria for clearance. Proceeding with those studies
in the absence of indications risks delay in treatment of other
injuries and, increasingly more important, unnecessary
exposure to radiation. The burden of unnecessary CT imaging in young trauma patients and the resultant cancer risk
should not be ignored.19 Each CT imaging study must be indicated by the real risk of injury and the absence of alternative
diagnostic approaches. Thoughtful serial physical examinations, adjunctive measures, and judicious use of plain lm
Box 7.3 Clearing Trauma Patients for Presence
of Vascular Injury
Head and Neck
n Alert, hemodynamically stable patient
n Absence of high-risk mechanism
n Normal neurologic examination
n Negative physical examination head and neck
n Absence of cervical spine or basilar skull fractures
Chest and Abdomen
n Normal chest and abdominal examination
n Absence of high-risk mechanism
n Normal chest x-ray, pelvis x-ray and negative FAST
Upper Extremity
n Alert, hemodynamically stable patient
n Normal upper extremity neurovascular examination
n Upper extremity fracture or penetrating proximity injury
n absence of significant hematoma or hemorrhage
n absence of neurologic deficit in distal arm or hand
n normal pulse examination or injured extremity index ≥0.9
Lower Extremity
n Alert, hemodynamically stable patient
n Normal lower extremity neurovascular examination
n Lower extremity fracture or penetrating proximity injury
n absence of significant hematoma or hemorrhage
n absence of neurologic deficit in distal leg or foot
n normal pulse examination or injured extremity index ≥0.9
In the hemodynamically stable patient with
3,16–18
Box 7.3 outlines the process of clearing for
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radiography can signicantly reduce the radiation exposure
without missing or delaying diagnosis of vascular injuries.
Definitive Diagnosis of Vascular
Injury
The nal diagnostic steps to conrm or denitively rule out
vascular injury include immediate operation and direct
examination of vessels, emergency center or intraoperative angiography, MDCTA, and formal catheter angiography.3 Each has its role in the denitive diagnosis of vascular
injury. Every trauma center must have the capability and
the practice guidelines to perform each of these denitive
steps. The following discussion provides the context for each
of these diagnostic techniques and presents a practice recommendation that can serve as a template for your trauma
practice group’s guideline.
SURGICAL EXPLORATION FOR VASCULAR INJURY
When should we take our patient at risk for major vascular injury directly to the operating room? Maybe the more
important question in an era of aggressive application of
MDCTA is when do we not need an imaging study before
we operate? The simple answer to these questions is that a
direct trip to the operating room without imaging is called
for when physical examination clearly indicates the location
and extent of injury and imaging adds nothing of signicant
decision-making value or incurs a delay that risks worsening the patient’s outcome.
3,20
Active arterial hemorrhage
from a penetrating wound or complete ischemia secondary to either penetrating or blunt trauma are the two most
frequent indications for immediate operation.3 If a patient
has a tourniquet placed on an extremity for hemorrhage,
the next stop should be the operating room. The value of
immediate operation for either hemorrhage or ischemia
has signicantly increased in the era of vascular damagecontrol techniques. Rapidly establishing vascular continuity with shunts and obtaining control of bleeding allows
time for treatment of other injuries and subsequent imaging studies for further workup without negatively impacting outcome. Fig. 7.5 outlines the indications for immediate
operation and the role of imaging modalities.
PORTABLE ANGIOGRAPHY IN THE TRAUMA BAY
OR OPERATING ROOM
Severely injured patients with severe life-threatening associated injuries who must be taken to the operating room pose a
challenge if vascular injury is suspected but hard signs are not
present. MDCTA may not be possible. An arteriogram can be
obtained in the trauma resuscitation bay or in the operating
room by cannulating the artery proximal to the suspected vascular injury, injecting 20 to 25 mL of full-strength contrast,
and taking an x-ray or using uoroscopy.
a rapid injection to shooting a single plain lm is important.
If these studies are inconclusive and major concern remains
about the presence of a vascular injury, there is a limited role
for operative exploration and direct assessment of the artery.3
However, in the absence of hard signs, these patients are better served by obtaining MDCTA when they are stable.
21,22
The timing from
Active arterial, major
venous hemorrhage
from wound
Hard signs of
vascular injury
Multilevel extremity
injury, unclear vascular
status (i.e., soft signs)
Unclear vascular status
and there is a need for
immediate operation
for other injuries
Fig. 7.5 Algorithm of the indications for immediate operation and the role of imaging modalities.
Ischemia, obvious
site of occlusion
Unstable patient
CT angiography and
positive for major injury
CT angiography and
positive for minimal injury
CT angiography
nondiagnostic
Pressure index < 0.9
Pressure index ≥ 0.9
Ta ke directly to the
operating room.
Ta ke to the operating
room ASAP.
Perform orthopedic
repairs as needed.
Follow closely for
compartment syndrome
and late thrombosis.
Formal catheter angiography
Perform single-injection
local angiography and
operative repair, if indicated.
Serial examinations
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MULTIDETECTOR CT ANGIOGRAPHY
The advent of 64-slice MDCTA has changed the time course
of denitive radiologic imaging for vascular trauma diagnosis.
This imaging technique has largely replaced catheter angiography.23 It is a very accurate and easy-to-obtain study with
excellent diagnostic imaging.24 MDCTA is discussed at length
in a subsequent chapter. However, patients with unequivocal
evidence of active hemorrhage or complete arterial occlusion
well localized by physical examination should not undergo
MDCTA. The delay to the operating room, the small but real
risk of contrast-induced nephropathy, and radiation exposure
are not worth the expense in terms of time delay and morbidity. Unfortunately, the widespread availability of MDCTA leads
to a very high rate of unnecessary studies. Each MDCTA must
be justied by balancing the value of diagnostic information
against the cost in time and morbidity.
CATHETER ANGIOGRAPHY
There is a denite role for catheter-based diagnostic imaging—often described as formal angiography. This technique
is particularly relevant when endovascular treatment of
arterial injury is an option. It is also an important step in
denitive diagnosis when MDCTA does not adequately
image vessels at risk (see Fig. 7.5). The presence of multiple
metallic fragments, such as those seen in shotgun injuries,
compromises the quality of MDCTA. Formal angiography
is required for denitive imaging in this setting. This technique is also discussed in a subsequent chapter. The most
important consideration in formal angiography is the time
required to mobilize the personnel to complete this study.
The 1-to-2–hour or more time period required for this study
must be carefully weighed against the overall priorities in
the care of the injured patient.
Compartment Syndrome
Compartment syndrome may occur shortly after injury,
in the subsequent initial resuscitation phase after lifethreatening hemorrhage, or 12 to 24 hours after reperfusion
following vascular repair.
compartment syndrome is one of the most common causes
12,25,26
Failure to diagnose and treat
of preventable limb loss following injury. The most common
location is in the calf, with the anterior compartment particularly vulnerable to this complication. Forearm compartment
syndrome is the next most common. However, compartment
syndrome can occur in the thigh, upper arm, foot, hand, and
buttocks. This syndrome most commonly occurs secondary
to prolonged ischemia or crush injury. A high index of suspicion, including checking for compartment syndrome as
part of an organized approach to the workup of all injured
patients plus frequent physical examination (augmented
with compartment pressure measurements), is necessary to
detect this complication in its early stage.
Although the rst clinical nding is loss of light touch sensation in the distribution of the nerve in the relevant compartment (e.g., peroneal nerve in the anterior compartment
of the lower leg), this nding is difcult to identify in many
patients due to distracting injury or altered mental status
from injury, alcohol, or drug intoxication.
12,25,26
The more
useful initial nding is pain on passive stretch of the extensor
hallucis longus muscle, elicited by pulling the great toe down
and placing its extensor muscle on stretch. Less specic is tenderness on direct compression. In the young and physically t
patient, the turgor and tautness (as opposed to suppleness) of
the compartment during direct digital compression is a discriminating physical nding. Extremity sensory and motor
examination is also not specic enough to be helpful in ruling
out the diagnosis of compartment syndrome. Similarly, the
loss of arterial pulses is a very late and relatively uncommon
nding unless there is underlying arterial injury.
12
The diagnosis of compartment syndrome should be considered in: all fracture dislocations at or below the knee
and elbow; all extremity crush injuries; and in any patient
complaining of increasing pain following injury. In view
of the nonspecic nature of the physical examination ndings and the multiple distracting factors, it is not surprising
that delay in diagnosis is unfortunately very common. Early
diagnosis is only possible through measurement of compartment pressures. Normal tissue compartment pressure
ranges from 0 to 9 mm Hg. Although controversy exists
about the pressure that denes compartment syndrome, the
safest approach is to perform fasciotomy when the compartment pressure exceeds 25 mm Hg.
12,25,26
There is a variety of methods used to measure compartment pressure. The Stryker Pressure Monitor (Fig. 7.6A) is
Fig. 7.6 (A) Stryker Pressure Monitor for compartment pressure monitoring. (B) Alternative device for pressure monitoring constructed from blood pressure cuff gage, pressure tubing, a stopcock, and syringe. Saline is flushed through the line to the 18-gauge needle. The compartment is entered with
the needle and three to five cc of saline are flushed into the compartment. The stopcock is turned to the gage to measure the compartment pressure.
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the most practical and commonly used device. If not available, an alternative device can be created with a blood pressure cuff manometer and saline ush tubing (Fig. 7.6B).
The pressure is measured in the four calf compartments or
the appropriate compartments in other areas of the extremities. If borderline elevation is noted, frequent serial measurements are essential in view of the progressive nature
of extremity compartment swelling. Fasciotomy techniques
are discussed elsewhere in this text.
Summary
Early diagnosis and prompt treatment are essential to the
successful management of vascular trauma. Timely diagnosis requires an organized approach based upon recognition of high-risk injury patterns, thorough physical
examination with adjunctive pressure measurements in the
extremities, and effective imaging techniques. The patient’s
major anatomic regions must each be evaluated for vascular injury by applying this organized approach. The denitive diagnosis of vascular trauma must be tailored to meet
the patient’s resuscitation priorities and orchestrated with
the overall care of associated injuries. This ranges from
immediate operation in unstable patients to delayed imaging in patients with suspected occult injuries.
References
1. Rozycki GS, Tremblay LN, Feliciano DV, McClelland WB. Blunt vascu-
lar trauma in the extremity: diagnosis, management, and outcome.
J Trauma. 2003;55:814–824.
2. Mattox KL, Feliciano DV, Burch J, Beall Jr AC, Jordan Jr GL, De Bakey
ME. Five thousand seven hundred sixty cardiovascular injuries in
4459 patients: epidemiologic evolution 1958 to 1987. Ann Surg.
1989;209:698–707.
3. Feliciano DV, Moore FA, Moore EE, etal. Evaluation and management
of peripheral vascular injury. Part 1. Western Trauma Association/
critical decisions in trauma. J Trauma. 2011;70:1551–1556.
4. Reason J. The Human Contribution. Unsafe Acts, Accidents, and Heroic
Recoveries. Surrey, England: Ashgate Publishing Ltd; 2008.
5. American College of Surgeons. Advanced Trauma Life Support. 10th ed.
American College of Surgeons; 2018.http://www.facs.org/trauma/
atls/index.html.
6. Bif WL, Moore EE, Ryu RK, Offner PJ, et al. The unrecognized
epidemic of blunt carotid arterial injuries: early diagnosis improves
neurologic outcome. Ann Surg. 1998;228:462–470.
7. Frykberg ER, Dennis JW, Bishop K, et al. The reliability of physical
examination in the evaluation of penetrating extremity trauma for
vascular injury: results at one year. J Trauma. 1991;31:502–511.
8. Miller PR, Fabian TC, Bee TK, Timmons S, Laneve L, Alexander RH.
Blunt cerebrovascular injuries: diagnosis and treatment. J Trauma.
2001;51:279–286.
9. Wall MJ, Tasi PI, Mattox KL. Heart and thoracic vascular injury. In:
Moore EE, Feliciano DV, Mattox KL, eds. Trauma. 8th ed. New York:
McGraw-Hill; 2017.
10. Shackford SR, Sise MJ. Extremity vascular trauma. In: Moore EE, Feli-
ciano DV, Mattox KL, eds. Trauma. 8th ed. New York: McGraw-Hill;
2017.
11. Dente CJ, Feliciano DV. Abdominal vascular trauma. In: Feliciano DV,
Mattox KL, Moore EE, eds. Trauma. 6th ed. New York: McGraw-Hill;
2004.
12. Whitesides TE, Heckman MM. Acute compartment syndrome:
update on diagnosis and treatment. J Am Acad Orthop Surg. 1996;4:
209–218.
13. Frykberg ER, Vines FS, Alexander RH. The natural history of clini-
cally occult arterial injuries: a prospective evaluation. J Trauma.
1989;29:577–583.
14. Johansen K, Lynch K, Paun M, Copass M. Non-invasive vascular
tests reliably exclude occult arterial trauma in injured extremities.
J Trauma. 1991;31:515–522.
15. Mills WJ, Barei DP, McNair P. The value of ankle-brachial index for
diagnosing arterial injury after knee dislocation: a prospective study.
J Trauma. 2004;56:1281-1265.
16. Kundson MM, Lewis FR, Atkinson K, Neuhaus A. The role of duplex
ultrasound imaging in patients with penetrating extremity trauma.
Arch Surg. 1993;128:1033–1038.
17. Frykberg ER, Crump JM, Vines FS, McLellan GL. A reassessment of the
role of arteriography in penetrating proximity extremity: a prospective study. J Trauma. 1989;29:1041–1052.
18. Dennis JW, Frykberg ER, Crump JM, Vines FS, Alexander RH. New
perspectives on the management of penetrating trauma in proximity
to major limb arteries. J Vasc Surg. 1990;11:85–93.
19. Brenner DJ, Hall EJ. Computed tomography – an increasing source of
radiation exposure. N Engl J Med. 2001;357:2277–2284.
20. Sirinek KR, Levine BA, Gaskill 3rd HV, Root HD. Reassessment of the
role of routine operative exploration in vascular trauma. J Trauma.
1981;21:339–344.
21. O’Gorman RB, Feliciano DV. Arteriography performed in the emer-
gency center. Am J Surg. 1986;152:323–325.
22. Morozumi J, Ohata S, Homma H, etal. Introduction of mobile angi-
ography into the trauma resuscitation room. J Trauma. 2009;67:
245–251.
23. White PW, Gillespie DL, Feurstain I, etal. Sixty-four slice multidetec-
tor computed tomographic angiography in the evaluation of vascular
trauma. J Trauma. 2010;68:96–102.
24. Inaba K, Branco BC, Reddy S, etal. Prospective evaluation of mul-
tidetector computed tomography for extremity vascular trauma. J
Trauma. 2011;70:808–815.
25. Wallin D, Yaghoubian A, Rosing A, Walot I, Chauvapun J, de
Virgilio C. Computed tomographic angiography as a primary diagnostic modality in penetrating lower extremity vascular injuries: a level I
trauma experience. Ann Vasc Surg. 2011;25:620–623.
26. Feliciano DV, Cruse PA, Spjut-Patrinely V, Burch JM, Mattox KL.
Fasciotomy after trauma to the extremities. Am J Surg. 1988;156:
533–536.
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Imaging for the Evaluation and
Treatment of Vascular Trauma
DAVID L. DAWSON
Background
The evolution of imaging for the diagnosis and treatment
of vascular injury has evolved with the development of
imaging technologies, increased availability of advanced
modalities, and changing treatment paradigms. Diagnostic arteriography was rst used in 1927 by Egas Moniz, a
neurologist. The technique for percutaneous access and
catheter exchange over a wire was developed in 1953 by
Sven-Ivar Seldinger, a radiologist. For a time, radiology was
the dominant specialty to perform angiography, but imageguided therapies are now commonly used by other specialties, including surgery. The use of angiography has been
broadened and inextricably melded with treatment.
Medical practice has evolved with the development of
new imaging capabilities. Arteriography was once the standard for nonsurgical evaluation of penetrating extremity
wounds in the absence of “hard signs” of vascular injury,
but noninvasive tests became widely adopted with the introduction of Doppler and ultrasound imaging options. The
increased availability of point-of-care ultrasound (POCUS),
including affordable hand-held systems, has provided
advanced imaging capabilities at the bedside and in the
eld. Computed tomography (CT) scanning was rst introduced to clinical practice in 1972, but it took more than two
decades of innovation, including helical acquisition with
high-resolution multidetector arrays and the development
of image postprocessing capabilities, to develop systems
that could be used for detailed vascular evaluations.
Computed tomography angiography (CTA) is now a standard for evaluation of extremity vascular injuries as well as
for potential injuries in the torso or cervical region.
widespread use of CT imaging for trauma has led to fundamental changes in trauma management paradigms, with
less invasive or nonoperative treatment strategies becoming
more common.3 Table 8.1 and the following paragraphs
provide an in-depth description of the various imaging
modalities used in the diagnosis, management, and followup of vascular trauma.
1,2
The
Imaging Modalities
ANGIOGRAPHY
Angiography is the term for direct imaging of any vascular
structure. Arteriography and venography refer more specically to imaging of arteries or veins, respectively. Intravascular injection of contrast agents allows visualization
of vascular anatomy and can be accomplished after direct
vascular puncture and placement of a needle or a catheter,
or by injection through a catheter that is manipulated into
the desired position from a remote access site. Angiographic
techniques are standard parts of general, trauma, and vascular surgery practice and may be applied in the resuscitation suite or operating room (OR). Diagnostic studies and
interventions are also performed by radiologists in specialized imaging suites. Transcatheter angiography provides
the highest-resolution imaging of most vascular beds. It
provides anatomic denition and a road map for surgical
planning or intervention (Tables 8.1 and 8.2)
Interpretation of angiography requires knowledge of
anatomy, physiology, and consideration of injury mechanisms. Vascular injury associated with hemorrhage can be
demonstrated by extravasation of contrast when bleeding is
brisk and ongoing, but extravasation may not be visualized
if the bleeding is slow or under tamponade. Bleeding may
also be overlooked on an imaging study if the injected contrast bolus is too small, if it is injected into a different vessel,
or if image acquisition is terminated too soon.
Angiographic interruption of vessel continuity indicates vessel disruption or thrombosis. With sufcient contrast injected, distal reconstitution of ow (i.e., beyond
the disrupted segment) from collateral vessels may be
demonstrated. Imaging of distal arterial beds can be compromised by hypoperfusion and vasoconstriction, typical
manifestations of hemorrhagic shock. Vasospasm, with
tapering of arteries (sometimes to occlusion) and slow
ow, can be more prominent in young patients who have a
greater degree of vasomotor reactivity. These ndings are
not necessarily indicative of injury or increased compartment pressure.
Early lling of the venous circulation following contrast
injection into the artery is a sign of an arteriovenous stula. Traumatic pseudoaneurysms result from focal disruption of arterial-wall integrity, with blood ow contained
only by the adventitia or surrounding tissues. A pseudoaneurysm appears as a focal outpouching of contrast beyond
the normal artery wall. Intimal aps and focal segments of
nonocclusive thrombosis may be detected as lling defects
or lucencies within the contrast column, sometimes with a
delay in distal contrast ow.
Indications
Transcatheter angiographic evaluation is a useful tool for
trauma patients, both to diagnose and to localize and treat
vascular injury. Conventional angiography may be necessary when images on CTA are obscured by artifacts caused
by metallic fragments, by soft-tissue air, or streak artifacts.
Thus, shotgun or wounds with multiple metallic fragments
are often best evaluated with direct catheter angiography
(Fig. 8.1). With complex wounding mechanisms, such as
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Table 8.1 Comparisons of Diagnostic Tests for Vascular Injuries
Diagnostic Modality Advantages Disadvantages Notes
POINT-OF-CARE TESTING
Doppler (continuous wave)• Limb pressure measurements
Ultrasound (POCUS)
ULTRASOUND
Vascular laboratory
ultrasound
ARTERIOGRAPHY
Direct injection
Digital subtraction
angiography
VOLUMETRIC IMAGING
Computed tomography
Magnetic resonance
imaging
FAST, Focused assessment with sonography for trauma; OR, operating room; POCUS, point-of-care ultrasound.
effectively screen for extremity
arterial injury
•
Real-time assessment of vascular patency or shunt function
•
Rapid
•
Safe
•
May add vascular assessment
to FAST
•
Follow-up after screening tests
•
May be used for serial examination of minor injuries
•
Simple
•
May be performed with portable C-arm or static images
•
Diagnostic
•
Guides interventional
therapies
•
Standard assessment tool in
trauma
•
Provides anatomic information
about vascular and nonvascular injuries
•
Specialized applications only
•
Secondary role for trauma
•
Indirect, provides only rough localization
of injuries
•
User dependent results
•
Most centers lack 24/7 availability
•
Not for unstable patients
•
Limited views
•
Risk of vessel injury from access or catheter manipulation
•
Contrast risk
•
Contrast risk, especially with multiple
studies
•
May be overused
•
Appropriate protocol and timing needed
for optimal vascular imaging
•
Long acquisition times
•
Many contraindications
•
Magnetic field limits support equipment
that can be used during imaging
•
•
•
•
•
•
•
•
•
•
Serial examinations may be useful for
monitoring
Available through all phases of care
Applicable to prehospital use
Follow-up after screening tests
Intraoperative assessment of grafts
Follow-up after vascular repairs
May be used to assess results of
revascularization procedures
May be performed with portable
system, imaging suite, or hybrid OR
24/7 availability in most trauma care
settings
Rarely used for trauma assessment
Table 8.2 Angiographic Findings With Common Vascular Injuries
Lesion Findings Notes
Arterial stenosis
Arterial occlusion
Active hemorrhage
Pseudoaneurysm
Arteriovenous fistula
high-energy explosives, vascular injuries needing repair
may be missed during early phases of care. For combatinjured soldiers evacuated through several echelons of
care, physical examination and clinical assessment may
be insufcient. Routine arteriography at centers providing
higher-level care can identify vascular injuries that may be
•
Narrowing of contrast column
•
Delayed distal filling
•
Focal area of lucency with intimal flap
•
Smooth, tapered stenosis with spasm
•
Occluded segment is not visualized
•
Limited collateral may be present with acute occlusion
•
Meniscus sign with embolic occlusion
•
Contrast seen tracking into extravascular tissues
•
Saccular aneurysm appearance
•
May have appearance of outpouching or bubble arising from artery wall
•
Early filling of adjacent arteries
•
Contrast moving into more central venous circulation
amenable to endovascular treatment. Thus, arteriography
should be considered in cases of complex trauma involving
high-energy, penetrating mechanisms or wounds in proximity to named vessels.
Transcatheter angiography is often used as part of a strat-
egy for endovascular therapy of vascular injury. As one
•
Intimal flap
•
Extrinsic compression
•
Spasm
•
Presence of prominent collaterals suggests
preexisting occlusion
•
Patient may be hemodynamically unstable
•
Extravasation may be active if pseudoaneurysm is not contained
•
May have reduced or absent distal arterial
flow
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8 • Imaging for the Evaluation and Treatment of Vascular Trauma 93
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Fig. 8.1 (A) CT overview scan in AP projection demonstrates multiple metallic pellets from a shotgun. (B) Metallic fragments create CT streak artifacts
that degrade imaging and interfere with postprocessing. (C) Digital subtraction arteriography is useful after shotgun or blast injuries with multiple fragments because there is a risk of significant injury to major arteries or branches. (D) Arrows highlight locations of several pseudoaneurysms that appear
as outpouchings from the artery.
example, if angiography demonstrates signicant arterial
injury, low-pressure ination of a compliant balloon may
be used to occlude ow into the damaged area. In these
types of cases, endovascular techniques may be used both
to control bleeding and accomplish denitive treatment of
the injury.
Preparation
As intravascular contrast agents are used for transcatheter arteriography and CTA and have the potential for
nephrotoxicity, it is important to be aware of the risk factors for renal injury. Post-contrast acute kidney injury
(PC-AKI) is the general term used for a decline in renal
function within 48 hours of intravascular administration of iodinated contrast medium. PC-AKI is a correlative diagnosis. It does not indicate that the contrast was
the cause of the observed deterioration in renal function.
Contrast-induced nephropathy (CIN) is the specific term
used when the cause of decline in renal function was
caused by the contrast administration. Factors associated with PC-AKI in trauma patients include hypotension (systolic blood pressure less than 80 mm Hg), heart
failure, advanced age (older than 75 years), anemia,
diabetes, preexisting renal insufficiency, and increasing
volume of contrast. Commonly used criteria for the diagnosis of PC-AKI or CIN include either a greater than 25%
increase of serum creatinine or an absolute increase in
serum creatinine of 0.5 mg/dL after administration of a
contrast agent.
Baseline renal function should be assessed prior to contrast administration, when possible. Patients at risk for
allergic reactions to contrast may be premedicated with
intravenous (IV) corticosteroids and histamine blockers.
Although allergies to shellsh do not predict risk of a contrast reaction, atopy or a history of prior contrast reactions may. Avoiding use of large doses of contrast (as may
occur in patients undergoing multiple imaging procedures),
avoiding hypovolemia (a practical concern in many trauma
patients), and monitoring renal function are recommended.
Use of iso-osmolar contrast (e.g., iodoxinol) and reduced
volumes of contrast reduce CIN risk. There is limited evidence suggesting that the use of N-acetylcysteine, theophylline, sodium bicarbonate, and statins further reduce the
incidence of CIN.
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94 SECTION 2 • Immediate Management and Diagnostic Approaches
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Pitfalls and Danger Points
The risks of contrast angiography include the following:
n Vascular access site complications, such as vessel injury
(e.g., hematoma, pseudoaneurysm, embolization, thrombosis)
n CIN
n Anaphylactic response to the contrast agent
n Technical and time requirements
n False-negative studies
n Risks of ionizing radiation
Catheterization for angiography poses a small risk of
iatrogenic vascular injury at the site of access. The risk of
access site injury is minimized with the use of ultrasound
guidance, direct operative exposure, and/or the initial use
of small-caliber access needles and wires (i.e., micropuncture devices). Diagnostic yield depends on the angiographic
technique used and the size and location of the vessel being
imaged. Injuries may be missed in high-ow vessels (such
as the aorta) due to rapid washout of contrast, or an injury
may be overlooked if imaging is performed in only a single
plane. Improper timing or an insufcient contrast bolus
may result in poor quality imaging, especially if the contrast is not directly administered into the vessel of interest
via selective or subselective catheterization.
There is attendant risk with the use of ionizing radiation
(x-rays) for angiography, though the risks to most patients
are usually negligible. Surgeons and staff who have regular exposure to x-rays during procedures should have specic training in radiation safety and practices to minimize
their own occupational radiation exposures. It is important
to note that scatter from the patient is the main source of
radiation to which medical personnel are exposed. Practices
to maintain exposure to levels as low as reasonably achievable (ALARA) should be mandated. Radiation doses may be
affected by factors that cannot be readily modied, including the size of the patient and the part of the body being
imaged. Specic actions to reduce radiation doses include
reduction of the time of exposure, increase of the distance
from the source of the scattered radiation, and effective use
of shielding (including lead garments and glasses).
Operative Strategy
There are three tiers of technical sophistication for trauma
arteriography, as follows: (1) simple “on table”; (2) portable C-arm; and (3) xed, oor, or wall-mounted system either in a dedicated suite (i.e., radiology department
unit) or in a “hybrid” OR space. Resource availability and
clinical circumstances typically dictate which approach
is used. Patients who are hemodynamically or physiologically unwell may need to be taken immediately to the OR for
management of their injuries. Although modern trauma
centers are moving to building xed imaging systems in
many of their trauma or resuscitative ORs,6 these advanced
capabilities may not be available in most centers. As such,
on-table angiography using several single-picture x-rays or
with a portable C-arm using basic cine loop angiography
(with or without digital subtraction) may be required.
Traumatic injuries of the descending thoracic aorta are
preferentially managed with thoracic endovascular aortic
repair (TEVAR) (Fig. 8.2).
7–9
Early experience with TEVAR
highlighted shortcomings of rst-generation graft devices,
which were designed primarily to treat aortic aneurysms.
However, current devices are available in sizes that better t
a normal-caliber aorta, and that better appose to the distal
transverse arch and proximal descending thoracic aorta.
Endovascular techniques can be used to manage hemorrhagic shock and certain patterns of vascular trauma,
including pelvic fractures with associated retroperitoneal
hemorrhage. Temporary deployment of an endovascular
balloon can provide proximal occlusion of the aorta for
hemorrhage control during open operative resuscitation
or surgical management of vascular injuries.10 In selected
cases, transcatheter management can provide denitive
therapy (Fig. 8.3).
11
The yield of angiographic identication of a pelvic source
of bleeding ranges from 43% to 78%.12 Sources of hemorrhage include injuries to major pelvic arterial and venous
Fig. 8.2 Blunt aortic injury. A pedestrian struck by an automobile arrived in the emergency department with hypotension (systolic BP 60 mm Hg), bilateral
pneumothoraces, and an open femur fracture. (A) Surface-shaded three-dimensional (3-D) rendering of CT angiogram of the chest demonstrated blunt aortic
injury (BAI). There is a pseudoaneurysm of the proximal descending thoracic aorta (yellow arrow). (B) Digital subtraction arteriography in left anterior oblique
projection demonstrates the aortic pseudoaneurysm (left image – yellow arrow) on the initial contrast injection. The follow-up aortogram (right image) after
placement of self-expanding covered stent (TAG Thoracic Aortic Graft, W.L. Gore and Associates) shows complete coverage of the injured segment.
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