Transcript A Retrospective Review of Patients with Aortic Trauma

A Retrospective Review of Patients
with Aortic Trauma
Ripal N. Shah
August 5, 2003
Research Mentor: Renan Uflacker, MD
Department of Radiology
Division of Interventional Radiology
Overview of Purpose and Methods

To review several factors that influence the initial management of aortic
injury including radiological studies, injuries to other systems,
morphology of aortic injury, and status on arrival to the hospital.

Charts were reviewed for those patients brought to MUH with
suspected vascular trauma.

The eventual objective of the review is to draw a correlation between
initial patient treatment and management to the subsequent outcome.

Radiographic techniques were analyzed for specificity, sensitivity, and
negative/positive predictive values.

Trends were identified and the statistics are presented.
Anatomy of Aorta
The aorta is the major artery that
supplies blood to the entire body.
Acute injury to the aorta is a severe
injury, and, left untreated, the patient may
become hypoxic or hypovolemic.
Severe brain injury (anoxic
encephalopathy) and ischemic damage to
other viscera can result from untreated
trauma.
As a result, timely, appropriate treatment
is necessary to avoid further morbidity and
mortality.
Causes of Aortic Injury



Overwhelmingly, the major cause of
traumatic aortic rupture is a rapid
deceleration type injury, such as in a
motor vehicle accident involving
anteroposterior force vectors.
In such cases, bony fragments of the
osseous structures of the chest wall
(sternum, manubrium, etc) resulting from
blunt trauma can be retroplused into the
mediastinum, rupturing the vasculature.
Other causes include: fall from a height,
stab wounds, and gunshot wounds.
Morphology of Aortic Injury




Contained rupture (traumatic pseudoaneurysm): in such cases, an intimal
flap is evident on CT, and a “double-barreled” aorta is seen at the level of
the pseudoaneurysm (60% of cases)
Contained partial or total transection of the aorta.
Intramural hematoma
The most common site of aortic injury is the aortic isthmus, the
region distal to the takeoff of the left subclavian and proximal to the
intercostal arteries
How severe is it?



80-90% of patients will not make it to the hospital.
Of those that do make it, 50% will die in 24 hours if
they do not receive appropriate treatment. Mortality
increases with amount of time left untreated.
For patients in which aortic injury is recognized and
treated, 80% are stable upon initial discharge.
Radiological Modalities and their Role in
Recognizing Aortic Injury

Chest X-Ray (CXR): initial study done on nearly all patients




signs on CXR suggestive of aortic injury include: widened
mediastinum (>8 cm), indistinct aortic knob contour, depressed left
main stem bronchus (>40 degrees below horizontal), loss of aortic
pulmonary window, and deviation of nasogastric tube.
Pneumothorax and hemithorax are considered nonspecific findings.
One or more of these findings (particularly widened mediastinum)
in patients with history of blunt chest trauma warrants additional
work up.
Computed Tomography (CT): very useful tool in diagnosing aortic
trauma. The standard of care for an abnormal CT with a conventional
scanner is to follow up with angiography. Newer modalities such as
helical and spiral CT scans have been shown to have a 100% negative
predictive value (ie, no false negatives).
Modalities contd.


Angiography: long considered
the “gold standard” in
diagnosing vascular trauma

sensitivity and specificity
approach 100%

drawbacks include expense,
length of procedure, and
invasiveness
Newer techniques include:
intravascular ultrasound (IVUS)
and transesophageal
echocardiography (TEE)
An example of an angiogram of the aortic arch
showing the takeoff of the great vessels:
bracheocephalic, left common carotid, and left
subclavian arteries.
Review of MUH Patients



48 patients were brought to MUH with the suspicion
of vascular trauma at the scene of the accident
23 patients were found to have aortic trauma upon
CT, angiography and IVUS
Of the remaining 25 patients, 13 were found to have
significant damage to other systems, but no vascular
injury. 12 patients had only minor injuries.
Is age a factor?



The average age of the entire patient set (n=48) is
39±19 yrs, with the youngest being 5 and the oldest 80
years old
The average age of the patients with vascular trauma
(n=23) is 36±19 yrs, with the youngest being 5 and the
oldest 80 years old
These statistics show us that no certain age group is more
likely to sustain aortic trauma than any other group.
Trends/Statistics

The 23 patients with aortic injury were retrospectively separated into two
groups: Group 1 – patients with aortic injury and surgical repair; Group 2 –
aortic injury but no surgery.

Of the entire set (n=23), 70% (n=16) underwent surgical repair, while 26% (n=
6) were treated conservatively, and one died prior to being taken to surgery

One false positive was identified on surgery.

Causes of trauma were as follows: 86% (n=20) MVA, 1 fall from height, 1
gunshot wound, and 1 stab wound

Of the MVAs, 4 were restrained, 6 unrestrained, 1 pedestrian vs. auto, 1
motorcycle vs. auto, 1 rollover, 1 ejection, and 6 of unknown restraint status.

Common associated injuries include neurological (closed-head injuries and spinal
cord compromise), abdominal visceral, and orthopedic injuries.
Statistical Analysis





CXR showed at least one suggestive sign of aortic injury in 17 of 23 patients
with vascular trauma (in most cases widened mediastinum)
CT done in 31 of 48 patients

NPV=79%, PPV=100%, Sn=80%, Sp=100%

4 false negatives, 0 false positives
IVUS done in 43 of 48 cases

NPV=100%, PPV=95%, Sn=100%, Sp=96%

0 false negatives, 1 false positive on surgery
Angiography done in 48 of 48 cases

NPV=90%, PPV=95%, Sn=87%, Sp=97%

3 false negatives, 1 false positive on surgery
Notes: NPV/PPV are negative and positive predictive values, Sn is sensitivity and
Sp is specificity; patients were considered positive for vascular injury if so
indicated by angiography or IVUS; mediastinal hematoma on CT is not
considered definitive of aortic injury
Diagnostic Studies




In most cases, patients underwent CT, Angiography and IVUS as
part of the diagnostic work up after initial CXR.
Interestingly, in Group 1 (patients with surgical repair), not a
single diagnostic study was negative. CXRs are not included
since they are not considered conclusive.
However, of the 6 patients in Group 2, 87% (n=5) had at least
one negative study and all patients had significant damage to
other systems, in addition to the vascular trauma.
These findings indicate that although surgical repair is the
preferred treatment of aortic trauma, conservative medical
management is opted for unless aortic injury is clearly seen.
More trends

74% (n=17) patients with vascular trauma had a
pseudoaneurysm or contained vascular leak; 13% (n=3) had a
partial or complete transection of the aorta; and 13% (n=3) had
an intramural hematoma



The diagnosis of intramural hematoma is interesting because the
only modality which can identify such trauma is IVUS.
This accounts for the 3 false negatives from aortography and 3 of
the 4 false negatives from CT
83% (n=19) had trauma in the proximal descending thoracic
aorta (in the region of the aortic isthmus); one patient had
pseudoaneurysm of the brachiocephalic artery, one had a left
common carotid pseudoaneurysm, one had an aortic tear over
the diaphragm, and one had a mid-thoracic aortic tear
Treatment Options

Surgical repair:



The treatment of choice is surgical repair.
Two options are “clamp and sew” and distal aortic perfusion techniques.
Recent studies have found distal perfusion techniques to reduce ischemic
injuries that may be seen with “clamp and sew” methods.
Endovascular stent-graft placement:



A minimally invasive approach to aortic repair.
A small incision is made in the femoral artery and with the aid of
angiography and fluoroscopy, a self-expanding wall stent is placed in the
region of trauma
A recent study found initial technical success to be 100%, with only one
mortality post-op. No mortality of morbidity in the remaining patients at 17
month follow-up.
Medical Management

In some cases, such as when craniotomy or exploratory laparotomy is
indicated, a more conservative course is pursued in the ICU.

In cases where surgical repair is not indicated, a pharmacological
beta-blockade regimen is recommended to reduce heart rate and
force of contraction and to control blood pressure.

Nitroprusside treatment can also be used to control blood pressure
and prevent rupture of the contained aortic rupture and
subsequent exsanguination
Further Study



Assess the impact of status at admission
Analyze discharge status and conduct
retrospective patient outcome survey
Correlate outcome data with hospital course
Case Report



HPI: 21 y/o white male brought to MUH post-MVA. Patient was
a restrained passenger in a single car MVA. Patient required 30
minute extraction time at scene of accident.
Physical Exam:
 Glasgow Coma Scale of 8
 only responded to painful stimuli
 visible fx of right femur and tibiofibular fx
 intubated and sedated at scene
Injuries identified at admission: subarachnoid hemorrhage,
aortic pseudoaneurysm, liver laceration, and serosal tears
intra-abdominally
Radiographic studies for vascular injury


CXR: widened mediastinum,
deviation of nasogastric tube to
right, suggestive of vascular injury
CT chest: traumatic
pseudoaneurysm of proximal
descending thoracic aorta (2 cm
cranio-caudally), mediastinal
hematoma, hemithoraces
(left>right)

Angiography: pseudoaneurysm at
level of ligamentum arteriosum

IVUS: confirmed findings of
angiography
Aortogram indicating pseudoaneurysm at level of
ligamentum arteriosum in this patient.
Hospital Course




After the diagnosis of aortic injury was made, the pt was not
considered a candidate for surgical repair due to his other injuries.
The pt was therefore put on beta blockade and his blood pressure
was closely monitored.
Neurosurgery also opted for conservative management of the
closed head injuries.
Exploratory laparotomy was performed on the day of admission,
and the liver laceration and serosal tears were identified and
repaired.
Pt also had orthopedic repair of femoral shaft fx same day
Course contd.




Once the patient was stabilized during his hospital course,
informed consent was obtained to repair the injured aorta (~17
days after admission)
The aorta was repaired with a Hemashield graft with left atrial
to distal aorta bypass using a posterolateral thoracotomy
incision (through the latissimus dorsi muscle).
The remainder of the hospital course was remarkable for an
infection that was effectively treated and a paralyzed left true
vocal cord.
The patient was discharged to the Marines on day 32 with CT,
neurosurgery, ENT, OT and PT follow ups scheduled.