1. Thoracic Great Vessel Injuries
Niqui Kiffin, M.D.
8 September 2009
Operative Skills Lecture

2. Introduction Injuries to the thoracic great vessels
Aorta & Branches
Brachiocephalic Artery
Subclavian Artery
Carotid Artery
Pulmonary Arteries/Veins
SVC/IVC
Innominate Veins
Azygos Veins
Injuries may be acute or chronic…
Acute
Death by exanguination
Chronic
Fistula formation
Post-traumatic pseudoaneurysm
Be aware of anatomic anomalies when assessing these patients

3. Anatomy

4. Etiology/Pathophysiology
Penetrating trauma
> 90% of thoracic great vessel injuries
GSW SW
Shrapnel
Iatrogenic
CVC placement
CT placement
IABP
ER Thoracotomy
Swan-Ganz balloon overinflation
Self-expanding metal stents (esophageal/tracheal)
Low-riding tracheostomy tubes

5. Etiology/Pathophysiology
Blunt Trauma
Particularly susceptible…
Innominate Artery
Pulmonary Veins
Vena Cava
Thoracic Aorta
Cause 10-15% of deaths following MVC
Prox descending – 54-65%
Ascending/Transverse arch – 10-14%
Mid- or distal descending – 12%
Multiple sites – 13-18%

6. Etiology/Pathophysiology
Blunt Trauma
Mechanisms…
Shear forces
Relative immobility of a portion of the vessel adjacent to a fixed portion
Atrial attachments – Pulmonary Veins, Vena Cava
Descending thoracic aorta - Ligamentum arteriosum/diaphragm
Compression
Between two bony structures
Innominate Artery – May be pinced between sternum and vertebrae
Profound intraluminal HTN

7. Etiology/Pathophysiology
Blunt Trauma (Aortic)
Most commonly full-thickness
Traumatic dissection is very rare
Equivalent to a ruptured aortic aneurysm that is contained by surrounding tissues (intact parietal pleura)
Maintain permissive hypovolemia and control tachycardia

8. Classification Exanguinating Hemorrhage Extensive multisystem injury
Die within 0-2 hrs of injury
Mortality – nearly 100%
Extensive multisystem injury
With hemorrhage often being from sites other than the thoracic aorta
Die within 2-4 hrs of injury
Mortality ~ 96%
CNS Injury
Usually hemodynamically stable, but die anyway
Mortality %

9. Prehospital Management
Judicious IVF administration
Excessive fluid resuscitation with the goal of increasing BP to normal or supernormal levels may actually increase mortality, ARDS, and other postop complications
Increased BP may actually “blow out” a soft perivascular clot
Endotracheal Intubation (+/-)
Rapid Transport

10. H & P
History
Length of knife, firearm type, number of rounds fired, and the patient’s distance to the firearm
Amount of hemorrhage at the scene, intermittent paralysis, or hemodynamic instability
Head-on and side-impact MVC
Commonly cause aortic injuries
Aortic injuries also reported with…
Equestrian accidents
Blast injuries
Auto-pedestrian accidents
Crush Injuries
Falls from height > 30 ft

11. H & P Physical ATLS Protocol Clinical findings…
Pericardial tamponade +/-
Hypotension
Upper extremity HTN
Unequal BP or pulses in the extremities
External evidence of major chest trauma
Expanding hematoma at the thoracic outlet
Intrascapular murmur
Palpable fracture of the sternum
Palpable fracture of the thoracic spine
Left flail chest
50% of pts with aortic/great vessel injury present without physical signs of injury
FAST U/S
Pericardial blood
+/- tamponade

12. Work-Up AP CXR (Penetrating)
Place radiopaque markers over penetrating wounds
Findings:
Large hemothorax
Foreign bodies
FB “out of focus”
Suggests intracardiac location
Trajectory with a confusing course
May indicate a migrating intravascular bullet
“Missing” missile with a GSW to chest
Suggests distal embolization in the arterial tree

13. Work-Up
AP CXR (Blunt)
7% of pts – normal appearing mediastinum on admission CXR
Loss of aortic knob contour
“funny looking” mediastinum
Mediastinal widening
> 8 cm
Tracheal deviation
Depression of the left mainstem bronchus
Apical pleural hematoma
Massive L hemothorax
Fractures
Sternal fracture
Scapula fracture
Multiple left-sided rib fractures
1st rib fractures

14. Initial Management ED Thoracotomy In extremis
4th ICS left anterolateral thoracotomy
Open pericardium
Cross-clamp aorta
Temporize bleeding
Open cardiac massage
Transport to the OR once vital signs re-established

15. Initial Management Tube Thoracostomy Hemo- or PTX
Attach tube to a repository for autotransfusion if significant output is noted.
Urgent Thoracotomy
> 1500cc initial output
> cc/hr

16. Initial Management
Avoid CVC in the upper extremities if concerned about a great vessel injury
Blood transfusion
Allow for moderate hypotension
Increased BP may “blow-out” a soft protective perivascular clot
Limit fluid administration until operative control of bleeding is obtained
Avoid HTN
Decreased incidences of ARDS and worsening of pulmonary contusions

17. Initial Management Beta-Blockade Decrease dP/dT
To minimize shear stress on the aortic wall
May be used in hemo-dynamically stable patients who require a delay for definitive treatment
Reduces the risk of fatal rupture
Retrospective data only…
No prospective data has demonstrated the safety or efficacy of such treatment

18. Initial Management Spiral CTA of the Chest Mediastinal hematoma
Intimal flap
Active extravasation

19. Initial Management Angiography
Essential for localizing the injury and planning the appropriate incision or placement of the graft if performing endovascular repair
“Negative” result
May convey false security
Laceration may have temporarily have sealed off
Column of aortic contrast may overly a small area of extravasation
Obtain multiple tangential views
Consider in pts…
Mechanism of injury PE
CXR
CT Chest
Also be aware that patients can have aortic ruptures even after seemingly innocuous mechanisms
Low-speed MVC
With airbag deployment
Intrascapular back blows to dislodge esophageal FB

20. Treatment Options Nonoperative Management
Consider in pts unlikely to benefit from immediate repair
Severe head injury
Risk factors for infection
Major burns
Sepsis
Heavily contaminated wounds
Severe multisystem trauma
Attempt to achieve physiologic optimization and improve the outcome of repair
Avoid HTN
Beta-Blockers
Has been used successfully in cases of “nonthreatening” aortic lesions (may heal spontaneously)
Small intimal flaps ( aorta/brachiocephalic)
Small pseudoaneurysms
Long-term natural history is uncertain, therefore close follow-up is recommended

21. Endovascular Stenting
Began in the 1990’s
Case reports and small series reported endografting of proximal descending thoracic aorta transections
Initially, surgeons were using custom devices with aortic/iliac extenders
Currently, device sizes range from 26-40mm
Avg diameter among patients with aortic injury 19mm
Manufacturers allow for 17% oversizing
When oversized > 17%, the graft is at risk for compression and enfolding
> 85% of injuries are < 1cm from the takeoff of the left subclavian artery
A seating distance on either side of the injury of 2cm is needed, therefore L subclavian artery occlusion is a risk with endovascular repair

22. Endograft vs. Open Techniques

23. Surgical Repair Indications for immediate operative intervention
Hemodynamic instability
Significant hemorrhage from CTs
Radiographic evidence of rapidly expanding mediastinal hematoma
Be aware…
Potential for neurologic complications
Paraplegia
Stroke
Brachial plexus injuries
Document a careful neuro exam
Prophylactic Abx
Limit fluid administration
Autotransfusion
Avoid wide swings in BP during induction

24. Surgical Repair Operative Approach
Depends on overall patient assessment and specific injury
Adequate exposure is critical in order to obtain proximal/distal control
Prep from neck to knees
In stable patients, CTA or formal angiography may help dictate the operative approach
Have appropriate graft material available
Prosthetic graft is preferred for vessel diameter > 5mm
Failure mode of infected graft = pseudoaneurysm
Infected saphenous vein = may cause graft dissolution with acute rupture and uncontrolled hemorrhage

25. Recommended Incisions
Uncertain Injury (Unstable)
L anterolateral thoracotomy
+/- transverse sternotomy
+/- right anterolateral thoracotomy (clamshell)
Ascending Aorta
Median Sternotomy
Transverse Aortic Arch
+/- neck extension
Descending Thoracic Aorta
L posterolateral thoracotomy (4th ICS)
Innominate Artery
Median Sternotomy with R cervical extension

26. “Clam Shell” Exposure

27. Clam Shell Exposure

28. Median Sternotomy Incision

29. Extending Sternotomy into Neck

30. Recommended Incisions
Right Subclavian Artery/Vein
Median Sternotomy with Right Cervical Extension
Left Common Carotid Artery
Median Sternotomy with Left Cervical Extension
Left Subclavian Artery/Vein
L anterolateral thoracotomy
3rd or 4th ICS with separate L supraclavicular incision
+/- connecting median sternotomy (Trapdoor)
Pulmonary Artery
Main/Intrapericardial
Median Sternotomy
Right or Left Hilar
Ipsilateral posterolateral thoracotomy

31. Recommended Incisions
Pulmonary Vein
Ipsilateral posterolateral thoracotomy
Innominate Vein
Median Sternotomy
Intrathoracic Vena Cava

32. Damage Control
Consider for patients with severely compromised physiologic reserve…
1. Definitive repair
2. Abbreviated thoracotomy
Control hemorrhage
Plan for reoperation
Examples:
Pneumonectomy
Temporary vessel ligation
Placement of intravascular shunts
Enmass closure of thoracotomy
Wound VAC
“Bogota Bag”
Sterile plastic bag used for abdominal wall closure

33. Arterial Injuries

34. Distribution of Arterial Injuries with Penetrating Mediastinal Trauma
Innominate 38%
Aortic Arch 28%
L CCA 18%
L Subclavian Artery 8%
Ascending Aorta 7%
K. Buchan and J.V. Robbs, Surgical management of penetrating mediastinal arterial trauma, European Journal of Cardio-Thoracic Surgery Volume 9, Issue 2, 1995, Pages Dept Surgery University of Natal, South Africa

35. Ascending Aorta Rarely survive transportation…
Total cardiopulmonary bypass
Usually required for posterior injuries
Dacron graft
Survival approaches 50% for patients with stable vital signs on arrival to the Trauma center
Always consider the possibility of a peripheral bullet embolus

36. Transverse Aortic Arch
Median sternotomy with extension into the neck
Provides complete exposure of the arch and the brachiocephalic branches
Exposure can be further enhanced by division of the innominate vein
Use of balloon tamponade my limit hemorrhage
Lateral arteriorrhaphy –simple repair
CP Bypass – posterior lacerations, concomitant pulmonary artery injuries
Survival also approaches 50%.

37. Innominate Artery Median Sternotomy +/- Cervical Extension
Blunt – Proximal injuries
Actually represent aortic injuries requiring proximal control at the transverse aortic arch
Penetrating – Injuries anywhere
Divide Innominate vein if necessary

38. Innominate Artery Partial Tears Complex Tears
Running lateral arteriorrhaphy 4-0 Prolene suture
Complex Tears
Bypass Exclusion Technique
Ascending Aorta to the distal innominate artery
Dacron graft
Avoid the area of injury until the areas for bypass insertion are exposed
No need for hypothermia, systemic heparinization or shunts…
Place a pericardial flap between the graft and the vein ( if vein left intact)

39. Innominate Artery

40. Descending Thoracic Aorta
Prehospital mortality 85% - blunt injury
If pts arrive alive, most injuries are located at the aortic isthmus
At the ligamentum arteriosum
Just distal to the take-off of the left subclavian artery

41. Descending Thoracic Aorta
Treatment Options
Clamp/Direct reconstruction with/without an interposition graft
Medical control of proximal HTN
Passive bypass shunts
Pump-assisted bypass
Traditional CP bypass (req. heparinization)
Atrio-femoral bypass using centrifugal pump (Heparin not necessary)
Nonoperative and/or purposeful delay of operation
Medical control of HTN
Close radiological monitoring
Endovascular Stenting

42. Descending Thoracic Aorta
Surgical Repair
Posterolateral Thoracotomy – 4th ICS
Proximal Control
Obtain control of the aortic arch between the L carotid and L subclavian artery
Avoid injury to L recurrent laryngeal nerve
CP should be available
Apply vascular clamps
Proximal aorta
Distal aorta
L subclavian artery
Close communication between surgeon and anesthesiologist
Clamping
Vasodilators – Prevents cardiac strain during clamping
Unclamping
Large volumes of fluid administration – Avoid clamp release hypotension

43. Descending Thoracic Aorta
Surgical Repair
Enter hematoma
Control intercostal artery bleeding
Avoid indiscrimnate ligation of intercostal vessels
Prox/distal ends of aorta are transected
Esophagus!!
Repair
End to End
Interposition graft

44. Descending Thoracic Aorta
Mortality rates
0-55%
Avg 13%
Primarily associated with multisystem trauma
Due to head injury, infection, respiratory insufficiency, and renal insufficiency

45. Descending Thoracic Aorta
Paraplegia
Most feared complication
Passive shunts and CP bypass – considerable debate
“Clamp-and-Repair”
Virtually the same incidence of paraplegia as traditional repairs with bypasses and shunts

46. Paraplegia Determinants are multifactorial… Perioperative hypotension
Injury/ligation of intercostal arteries
Duration of clamp occlusion
Length of cross-clamp time does not directly correlate with the occurance of paraplegia
< 30 minutes has been argued to provide a safe margin against paraplegia
Recommend shunting techniques if > 30 minutes, however shunt provides no protection for the region of spinal cord that is supplied by the clamped arteries
Also, recognize that pts requiring > 30 min of clamp time have more extensive injury…therefore it is likely that the increased paraplegia in this subset of patients is actually secondary to more extensive disruption of intercostal arteries and other flow to the anterior spinal artery caused by the original injury

47. Subclavian Artery Intrathoracic Thoracic Outlet Cervical (Zone I)
Upper Extremity

48. Subclavian Artery R Subclavian Artery L Subclavian Artery
Median Sternotomy +/- cervical extension
L Subclavian Artery
Proximal Control
Anterolateral Thoracotomy (2nd/3rd ICS)
Distal Control
Supraclavicular Incision
Can be combined with infraclavicular incision to avoid removal of clavicle
May be connected with a sternotomy (“Trapdoor”)
Deltopectoral groove incision
May also consider removal of clavicle

49. Subclavian Artery Avoid injuries to phrenic nerve
High associated rate of brachial plexus injuries
Repair
Lateral Arteriorrhaphy
Interposition Graft
Rarely end-to-end anastomosis

50. Left Carotid Artery
Mirrors the approach for an innominate artery injury
Median sternotomy +/- L cervical extension
Transection at the origin
Bypass graft repair
Preferred over end-to-end anastomosis

51. Pulmonary Artery Intrapericardial Median Sternotomy
Minimal dissection – Main/Prox L
Dissect between the SVC and ascending aorta
Anterior injuries – primary repair
Posterior injuries – CP bypass
Mortality rates approach 70%

52. Pulmonary Artery Distal Present with massive hemothorax
Repair via an ipsilateral posterolateral thoracotomy
Rapid Pneumonectomy
May be necessary in a life-threatening situation
Tamponade with balloon…
Exanguinating hemorrhage

53. Internal Mammary Artery
May produce massive hemothorax or pericardial tamponade
Usually discovered by accident when thoracotomy performed for suspected great vessel or cardiac injury
May be ligated for control

54. Intercostal Arteries May cause massive hemothorax
Ligation is necessary for control
May require large sutures taken circumferentially around the rib proximally and distally

55. Venous Injuries

56. Thoracic Vena Cava Isolated injury to suprahepatic IVC or SVC is rare…
Mortality > 60%
Intrathoracic IVC
Hemopericardium +/- tamponade
Exposure is extremely difficult
Usually requires total CP bypass with the inferior cannula in the groin
Enhanced repair by opening the right atrium and placing a balloon in the cava to prevent air embolus and massive blood return t the heart
Repair is done from the inside of the cava via the R atrium
SVC
Lateral venorrhaphy
May require an intracaval shunt
May use…
PTFE or Dacron interpostion graft
May also use saphenous vein panel grafts
Usually too time-consuming
Risk for blow-out

57. Pulmonary Veins Difficult to manage via an anterior incision
Usually requires an ipsilateral thoracotomy
Consider temporary occlusion of the hilum
If ligation is necessary…
Resect the lobe as well

58. Subclavian Veins Operative approach similar to arterial repair Repair:
Lateral venorrhaphy
Ligation

59. Azygos Vein Not usually considered a thoracic great vessel
However…large size and high flow cause injuries to be life-threatening
Best managed by suture ligation of both sides of the injury

60. Special Problems...

61. Systemic Air Embolism
Caused by a penetrating wound that injures a pulmonary vein and bronchiole and forms a fistula
Allows air bubbles to enter the L heart and embolize to the systemic circulation
Coronary Arteries – MI, cardiac arrest
Cerebral Arteries – Seizures, CVA, death
Treatment
Thoracotomy
Clamping of the pulmonary hilum to prevent further embolization
Aspiration of the air from the left ventricle
Trendelenburg position with right side down

62. Foreign Body Embolism
Thoracic great vessels may serve as both an entry site or final resting place for intravascular bullet emboli
May produce infection, ischemia, or injury to organs distant from the site of trauma
25% lodge in the pulmonary arteries
Should be removed to prevent pulmonary thrombosis, sepsis or other complications
May be done via fluoroscopic guidance or open technique

63. Post-Op Management

64. Post-Op Management Careful hemodynamic monitoring
Avoid HTN and hypotension
IVF, pressors, and vasodilators
Pulmonary Complications
Atelectasis
PEEP
Respiratory Insufficiency
Pneumonia
ARDS
Close monitoring of fluid administration

65. Post-Op Management Hemorrhage Technical problem Coagulopathy
Urgent re-operation
Coagulopathy
Monitor/Correct with administration of FFP, cryo, etc…

66. Post-Op Management Graft Infection Long Term Complications
Avoid bacteremia
Strict sterile placement of CVC
Post-op abx as needed
Prophylactic Abx
Prior to invasive procedures
Dental, etc
Long Term Complications
Stenosis
Thrombosis
AV Fistula
Pseudoaneurysm formation

67. Conclusion Many patients with great vessel injury die in the field.
Many die from exanguination, while others have an assortment of associated injuries
Those pts that arrive in the trauma center should be treated rapidly
Follow ATLS protocol
Rapid assessment of injuries
Quick transport to CT/Angio/OR
Be aware of anatomical variations
Have a multitude of incisions in your armamentarium
Be aware of when/where to use damage control operations