WSES position paper on vascular emergency surgery

Blunt thoracic vascular injuries

Blunt thoracic aortic injury is the most severe thoracic vascular injury. This is
a specific clinical syndrome related to high impact deceleration injuries and high
injury severity scores. Although treatable, it causes significant mortality related
partially to delayed diagnosis 25]. About 50 % of victims die on impact, in the rest the bleeding is temporarily contained
by the aortic adventitia and pleura and these patients are potentially salvageable.
The injury typically occurs at the site of the ligamentum arteriosum, just distal
to the take off of the left subclavian artery. Shear forces and stretching of the
aorta are likely mechanisms of injury. The classic sign of widened mediastinum is
unreliable and investigation should be carried out in cases where there is a high
index of suspicion 31]. No controversy remains regarding arch arteriography or CT scanning: Moore et al.
demonstrated CT had essentially 100 % negative predictive value 31]. It appears that the use of heparin-bonded shunts allows improved results with a
lower incidence of paraplegia. Endovascular techniques are playing an expanding role
in the treatment of this problem 32]. Massive hemothorax requiring thoracotomy is defined as plus to 1–1.5 L at the time
of insertion of chest drains or 200–300 ml/hr for the subsequent 4 h. Some of these
cases will involve injury to the pulmonary vessels 33], 34]. Operative repair of aortic arch is through a median sternotomy and may require use
of total cardiopulmonary bypass and insertion of a graft.

The overall incidence of blunt aortic injury has remained the same over the past 12 years
despite advances in vehicle restraint systems 33].

Similar mechanisms are implicated in the injury of the non-aortic great vessels as
well. Regardless of the mechanism or mechanisms, the result is vessel wall disruption,
occlusion, or avulsion. Shearing can result in all of these and compression more often
results in occlusion. A small intimal disruption can lead to thrombus formation and
subsequent vascular occlusion 34]. Innominate artery and left carotid injuries usually occur proximally at the vessel
origin. In contrast, blunt subclavian injuries tend to be more distal 11], 35].

Comparing those patients with penetrating injury, blunt thoracic great vessel injuries
are less incident. In general, penetrating injuries result in higher mortality, more
combined arterial and venous injures, and lower morbidity than those presenting with
blunt trauma. Mortality for blunt injury has been reported between zero and 24 %.

Penetrating thoracic vascular injuries

In thoracic penetrating injuries, the trajectory of the projectile or of the blunt
object is the key to determine the anatomic structures involved. In general, missile
trajectories that pass through the midline are at more risk for significant vascular
injuries 36], 37].

Penetrating injuries involving the ascending arch of the aorta are uncommon. Survival
rates approach 50 % for patients having stable vital signs on arrival at a trauma
center. Although primary repair of anterior lacerations can be accomplished without
adjuncts, cardiopulmonary bypass may be required if there is an additional posterior
injury.

For an injury to the transverse aortic arch, extension of the median sternotomy to
the neck allows complete exposure of the arch and brachiocephalic branches. If necessary,
exposure can be enhanced further by division of the innominate vein. Simple lacerations
may be repaired by lateral aortorrhaphy. With difficult lesions such as posterior
lacerations or those with concomitant pulmonary artery injuries, cardiopulmonary bypass
can be employed 38].

Patients with thoracic vascular injuries are either exsanguinating or have a potential
bleeding contained injury. In one way or another one should be followed up in a TICU
or SICU.

Bellow you find author’s recommendations for both blunt and penetrating mechanism
of injury.

Authors recommendations by vessel injury

Innominate Artery Descending Thoracic Aorta

The proximal innominate artery and aortic arch are best approached by a median sternotomy.
Early ligation of the innominate vein as well as associated thymic tissue in the anterior
mediastinum will aid in exposing the aortic arch.

The proximal descending aorta is approached by a postero-lateral thoracothomy.

Traumatic blunt ruptures of the aorta are typically found just distal to the ligamentum
arteriosum.

For selected patients with only partial tears of the aortic arch, a continuous lateral
arteriorrhaphy using 4–0 polypropylene suture is occasionally possible.

If patients have stable thoracic hematomas and concomitant abdominal injuries for
which they are unstable, laparotomy should be the initial procedure.

For patients with rapidly expanding mediastinal hematoma, however, repair of thoracic
injuries should be the primary therapeutic goal.

Injury to the descending thoracic aorta is approached by way of a postero-lateral
thoracotomy through the fourth intercostal space.

The current standard technique of repair involves vascular clamping and direct reconstruction.
Three commonly employed adjuncts to this approach include pharmacologic agents; temporary,
passive bypass shunts; and pump–assisted left heart bypass.

Vascular clamps are applied to the aortic arch, distal aorta, and left subclavian
artery. Close communication between the anesthesiologist and surgeon should occur
to maintain stability of hemodynamic parameters. The hematoma is entered, and care
is taken to avoid indiscriminate ligation of intercostal vessels; only those required
for adequate repair of the aorta should be ligated. The proximal and distal ends of
the aorta are completely transected and dissected away from the esophagus. The injury
then is repaired by either end–to–end anastomosis or graft interposition.

The authors have advocated simple clamp-and-repair for injuries to the descending
thoracic aorta (without the use of systemic anticoagulation or shunts), a technique
that continues to be used with excellent results.

Regardless of the technique used, paraplegia occurs in approximately 8 % of patients
undergoing to descending thoracic aorta repair. Unless operative time is 30 min,
partial left heart bypass is superior to clamp-and -sew in preventing paraplegia.

Subclavian vessels

For subclavian injuries, a cervical extension of a median sternotomy is employed
for exposure of right–sided subclavian injuries. For left subclavian artery injures,
proximal control is obtained through an anterolateral thoracotomy (third intercostal
space), while a separate supraclavicular incision provides distal control.

In subclavian vascular trauma, a high associated rate of brachial plexus injury is
seen.

Documentation of preoperative neurologic status is important, in all thoracic and
neck vascular injuries.

Repair of subclavian arteries can usually be accomplished with either lateral arteriorrhaphy
or graft interposition. Any difficulty in exposure can be managed with division or
resection of the clavicle exposing the more distal subclavian.

Subclavian reconstruction commonly requires the use of a graft (Dacron or PTFE).
In the patient, in extremis flow can be reestablished with the use of a shunt, or
the artery can be ligated as a life–saving measure.

Operative exposure of the subclavian veins is equivalent of that described for subclavian
artery injuries: median sternotomy with cervical extension for right-sided injuries
and left anterolateral thoracotomy with a separate supraclavicular incision for left-sided
injuries.

Repair should be performed by either lateral venorraphy or ligation.

Pulmonary artery veins

The intrapericardial pulmonary arteries should be approached via median sternotomy.

Exposure of the intrapericardial right pulmonary artery is achieved by dissecting
between the superior vena cava and the ascending aorta.

Mortality rates for injury to the central pulmonary arteries or veins are high (70 %).

When there is a major hilar injury, rapid pneumonectomy may be a lifesaving maneuver.

Injuries to the pulmonary veins are difficult to manage through an anterior incision.

With major bleeding, temporary occlusion of the entire hilum may be necessary.

If a pulmonary vein must be ligated, the appropriate lobe will need to be resected.