APPENDIX B: TORSO VASCULAR INJURY

THORACIC AORTA

- Recommendations: Selective repair
- Utility of temporary shunt: None, except in extremis
- Method/Conduit: Observation and medical optimization or Dacron graft replacement

Pearls

- If a stable blunt injury, MEDEVAC to Role 3 for possible repair versus MEDEVAC to Role 4.
- Permissive hypotension or B-blocker may decrease risk of rupture.
- If hemorrhage from penetrating wounds, clamshell thoracotomy and one lung ventilation to facilitate exposure of the proximal descending aorta.

Management of penetrating injury to the thoracic aorta is very rare given the pre-hospital lethality of this injury. If present, management of thoracic hemorrhage in the setting of penetrating trauma is directed by chest tube location and output (i.e. the hemithorax which is bleeding from tube thoracostomy is the one which is opened). The descending thoracic aorta is approached through the left chest and when injured is surrounded by hematoma. An initial left thoracotomy can be extended into the right chest to approach the thoracic aorta by extending across the sternum (“clam shell” thoracotomy). Aortic control proximal and distal to the hematoma must be obtained including isolation or control of any intercostal arteries in this segment. Aortic clamps are used to arrest flow in this segment and the hematoma is entered with debridement of the injured aorta using scissors. An adequate length of aorta must be debrided to allow placement of large caliber (20-26mm) Dacron graft sewn end-to-end to the proximal and distal segments.

Management of blunt injury to the thoracic aorta (partial transection or pseudoaneurysm) which has reached a temporary stable equilibrium is more common. In this setting and in the absence of hemorrhage from chest tubes, contrast CT imaging is indicated to characterize the injury. Permissive hypotension and selective use of B-blockers is indicated to decrease the risk of aortic rupture during this period. Impulse control parameters should target a goal heart rate of <80 and a systolic blood pressure of <120 mmHg. If CT confirms blunt aortic injury, options include early open repair or MEDEVAC. Blunt aortic injury may have associated thrombus or intimal injury seen on CTA and anticoagulation versus anti-platelet therapy should be considered in the context of concomitant injuries. In a patient at Role 1 or 2 with a suspected blunt aortic injury who has normal and stable vital signs and no signs of active hemorrhage from the thorax, MEDEVAC to the Role 3 should occur. At this location the decision will be made regarding options for open or endovascular repair or medical optimization and critical care transport out of theater. Recent advances in in-theater endovascular capability have made endovascular repair of such injuries possible at certain Role 3 facilities, though this is not common.1,2

ABDOMINAL AORTA

- Recommendations: Repair
- Utility of temporary shunt: Low
- Method/Conduit: Interposition graft with Dacron (rifampin soaked), aortic sizers helpful in determining graft conduit diameter

Pearls

- Supraceliac aortic control requires high midline incision along xyphoid, spreading and suspension of rib cage with retractors and nasogastric tube in the esophagus. Divide the entirety of the right crus overlying the aorta.
- Approach supra-mesocolic Zone I hematomas with left medial visceral rotation (Mattox maneuver).
- Approach infra-mesocolic Zone I hematomas with right medial visceral rotation (Catell-Brash maneuver).
- Keep in mind that supra-mesocolic Zone I hematomas may contain transected pancreas.

Blunt and penetrating injuries to the abdominal aorta present as a central (zone I) hematoma with blood in the abdomen at laparotomy. Zone I hematomas should be considered in two locations, supra- or infra-mesocolic, and should be entered once proximal and distal control is established and blood and access are available for transfusion. Supra-mesocolic, Zone I hematomas are best approached by left medial visceral rotation (i.e. Mattox maneuver) which exposes the supraceliac, paravisceral and infrarenal segments of aorta. Infra-mesocolic Zone I hematomas should be approached with the Catell-Brash maneuver exposing the infrarenal aorta and inferior vena cava up to and behind the liver. Proximal aortic control is obtained through the gastrohepatic ligament by retracting the esophagus to the left and dividing the crus. Alternatively, the Mattox maneuver exposes the supraceliac aorta from the lateral position, enabling proximal control as well. The iliac vessels or distal aorta can next be controlled, providing isolation before entering the hematoma. Repair techniques for the aorta and its branch vessels range from primary pledgetted closure to replacement with a Dacron interposition graft and depend upon the degree of injury.

VENA CAVA

- Recommendations: Repair
- Utility of temporary shunt: Low
- Method/Conduit: Lateral repair, patch angioplasty or interposition graft / ePTFE

Pearls

- Establish resuscitation lines above the diaphragm for abdominal vena cava injuries.
- Vena cava injuries should be exposed using the Catell-Brash and Kocher maneuvers.
- Lateral repair is acceptable provided that no more than 1/3rd of the lumen is compromised.
- If occlusion of the cava results in hypotension, clamp the aorta to support central perfusion.
- Retrohepatic, retroperitoneal hematomas should not be disturbed if not actively bleeding.
- Several specific strategies applicable to repair of the injured vena cava are listed in the Large Vein Injuries section.
- Equipment: Self retaining retractor system (i.e. Omni or Bookwalter)

The approach to the vena cava in the abdomen should be performed using the Cattell-Brasch and Kocher maneuvers to expose the cava, renal veins, and the distal portion of retrohepatic segment. Mobilization of the liver is required to expose the retro-hepatic vena cava; however, retrohepatic hematomas should not be disturbed if there is no active bleeding.

Attempts should be made to identify large lumbar veins feeding into the injured segment which may bleed as much as the main channel of the vena cava if not controlled. Because repair of the vena cava is likely to require intermittent occlusion (i.e. sponge sticks or vascular clamps) or ligation in extreme cases, central venous access should be established above the diaphragm (i.e. subclavian or jugular veins) to allow effective volume resuscitation. If compressing or occluding the vena cava results in significant hypotension, the adjacent infrarenal abdominal aorta may be temporarily occluded to support central pressures while resuscitation takes place. Repair of tangential injuries to the cava can be accomplished using lateral suture repair (i.e. running venorrhaphy) provided that the lumen is not narrowed more than ½ of its native diameter. If lateral repair results in significant narrowing, there is a higher risk of thrombosis leading to pulmonary emboli and anticoagulation should be initiated postoperatively if possible. In instances where lateral repair will result in more than 50% narrowing, patch angioplasty or resection and interposition graft using ePTFE is preferable. Ligation of the infrarenal cava is acceptable as a damage control maneuver, although this carries a significant mortality risk and major morbidity in the form of decreased cardiac preload and significant lower extremity edema. If infrarenal ligation is needed, it should always be accompanied by bilateral lower leg fasciotomies to reduce the risk for compartment syndrome. Suprarenal occlusion of the IVC is generally not compatible with survival and should be considered a measure of last resort.3

PORTAL VEIN AND HEAPTIC ARTERY

- Recommendations: Repair
- Utility of temporary shunt: Low (high probability of shunt thrombosis)
- Method/Conduit: Primary repair, patch angioplasty, interposition graft / ePTFE or Dacron or saphenous vein

Pearls

- Access to gastrohepatic ligament by Pringle maneuver should precede exploration of the porta hepatis.
- Ligation of hepatic artery injuries is acceptable if the portal vein is patent.
- Lateral venorrhaphy is preferred, ligation of portal vein results in massive bowel edema and systemic hypovolemia.
- Several specific strategies applicable to repair of the injured portal vein are listed in the Large Vein Injuries section (section VII).

Portal vein and hepatic artery injuries typically present as hematomas of the porta hepatis and should be explored after isolation of the gastrohepatic ligament and application of a Pringle maneuver. Next, careful dissection of the porta is performed to determine which structures have been injured. Injuries to the hepatic artery may be repaired with lateral suture placement if limited in severity; ligation of the hepatic artery is acceptable if the portal vein is uninjured. Repair of the portal vein should be attempted using the technique of lateral venorrhaphy if possible. If a large segment of the portal vein is damaged, vein patch angioplasty, or in rare instances, interposition vein graft may be performed. Ligation of the portal vein is an option of last resort and will result in hepatic ischemia and splanchnic congestion and hypervolemia for several days. Importantly, if the capabilities are available, then imaging of the biliary system should be considered for associated injuries of the common bile duct and can be performed with cholangiography through the gall bladder.

MESENTERIC ARTERIES

- Recommendations: Repair
- Utility of temporary shunt: Low (high probability of shunt thrombosis)
- Method/Conduit: Primary repair, patch angioplasty, interposition graft / ePTFE or Dacron or saphenous vein

Pearls

- Present as supra-mesocolic Zone I hematoma.
- Repair proximal mesenteric artery and vein injuries including portal vein.
- Ligation can be performed for distal artery and vein injuries or as damage control.

Upon entering a supra-mesocolic Zone I hematoma, one may find injury to the mesenteric vessels (artery or vein). Under most circumstances, repair of the proximal superior mesenteric artery and vein, including the portal vein, is indicated using the techniques of primary pledgetted repair, vein patch angioplasty or replacement of the injured segment with interposition saphenous vein graft. The specific type of repair will depend on the location and extent of vessel injury. In cases where injury to the artery or vein is distal (i.e. beyond the middle colic artery or jejunal vein branches) or in which the patient’s physiology is severely compromised, the vessels can be ligated.

RENAL ARTERIES

- Recommendations: Selective repair
- Utility of temporary shunt: Low
- Method/Conduit: Primary repair or patch angioplasty/Dacron or vein

Pearls

- Explore Zone II hematomas from penetrating injury.
- Establish status of contralateral kidney by contrast study or manual palpation.
- Priority is “save-life,” and early nephrectomy is required with complex injuries.
- With a renal warm ischemic time > 30-60 minutes, complex repairs are not indicated.
- Injury to the renal pedicle (blunt or penetrating) is closely associated with injury to the parenchyma; isolated arterial injury is rare. Essential considerations in the management of renal artery injury in wartime are the warm ischemic time of 30-60 minutes and complexity of renal artery repair, as times longer than this has dismal renal preservation rates. Both of these limits what the surgeon can accomplish in the context of renal artery injury other than ligation and nephrectomy.
- If arterial injury manifests as occlusion with renal ischemia, it will be too late to restore flow and function to the kidney by the time the diagnosis is made in the operating room or CT scanner. If the artery is patent and bleeding, an associated Zone II or lateral hematoma requiring exploration will be present and attempts to stop hemorrhage and repair are indicated. These maneuvers may include pledgetted primary repair of the renal artery, patch angioplasty or very rarely interposition graft replacement (aorto-renal bypass). Again, considering the warm ischemic time of the kidney, complex operations to maintain or reestablish perfusion in the renal artery are not recommended and should be abandoned in favor of nephrectomy in most cases.
- The method by which to approach an expanding or penetrating Zone II hematoma is controversial and case specific. Isolation of the renal pedicle before exploring the hematoma is doctrine in many institutions and has the advantage of aortic isolation and definitive proximal control. However, from a practical standpoint, mobilization of the damaged kidney from a lateral to medial direction without hilar control may be faster depending upon the appearance of the injury. The lateral to medial approach is like the medial visceral rotation performed for Zone I injuries.

ILIAC ARTERIES

- Recommendations: Repair
- Utility of temporary shunt: High (low probability of shunt thrombosis)
- Method/Conduit: Interposition graft/ ePTFE or Dacron or saphenous

Pearls

- Explore Zone III hematoma from penetrating wound after establishing aortic control above the hematoma.
- Distal control is obtained at the inguinal ligament (i.e. external iliac arteries).
- Wylie hypogastric (internal iliac) clamps facilitate low-profile control of iliac arteries.

Iliac artery injuries generally present as a Zone III or pelvic hematoma with or without extremity ischemia (check femoral pulses). Exploration of the hematoma should be performed after proximal control is obtained at the infrarenal aorta, the contralateral iliac artery if possible, and ipsilateral distal external iliac artery. The distal external iliac artery should be located as it exits the pelvis at the inguinal ligament at a point where it is free from the hematoma. The internal iliac artery may not be initially controlled or visualized before exploring the hematoma, which often requires opening to expose the internal iliac. The inability to initially control all bleeding from the hematoma necessitates preparation including multiple suction devices, Fogarty occlusion balloons (if available) direct tamponade strategies or devices and alerting anesthesia regarding the need for continued resuscitation during exploration. After proximal and distal control of the common and external iliac arteries is obtained, the hematoma is entered which facilitates exposure and clamping of the internal iliac artery and the injured vessel(s). Common and external artery injuries can be controlled and managed with a temporary vascular shunt if needed or repaired with interposition grafting using saphenous vein or prosthetic conduit (6-8mm ePTFE or Dacron). In an unstable patient or a patient where there is contamination of the field, shunt placement with definitive repair or reconstruction done at a later point is a good option.

If the primary injury is to the internal iliac artery (hypogastric), it may be ligated with 3.0 or 4.0 Prolene on an SH needle. Bleeding from associated iliac veins may be severe and difficult to expose. The iliac artery may be divided, if necessary, to facilitate exposure of the iliac vein, followed by repair of the artery. At certain Role 3 facilities with endovascular capabilities, selective embolization of bleeding hypogastric artery or branches is an option, particularly in blunt trauma (e.g., pelvic fracture.) The principles which apply to the management of iliac vein injury are discussed in the Management of Large Vein Injuries Section.

REFERENCES

1. Feliciano DV. Management of traumatic retroperitoneal hematoma. Ann Surg. 1990; 211:109-123.
2. Propper BW, Alley JB, Gifford SM, Burkhardt GE, Rasmussen TE. Endovascular treatment of a blunt aortic injury in Iraq: extension of innovative endovascular capabilities to the modern battlefield. Ann Vasc Surg. 2009;23(5):687.e19-687.
3. Sullivan PS, Dente CJ, Patel S, et al. Outcome of ligation of the inferior vena cava in the modern era. Am J Surg 2009;199:500-6.