Abdominal vascular injury

INTRODUCTION — Some of the most challenging and complex injuries involve trauma to vascular structures of the abdomen, retroperitoneum, and pelvis. The hallmarks of vascular injury and its sequelae include difficulty obtaining immediate proximal control and adequate exposure, repairing injury in the face of contamination, managing the consequences of ischemia to critical end organs, and providing long-term surveillance to follow-up for patency.

The general principles for identifying and managing abdominal vascular injury are reviewed here. The initial management of the patient with blunt or penetrating abdominal injury that might result in vascular injury is reviewed separately. (See "Initial evaluation and management of blunt abdominal trauma in adults" and "Initial evaluation and management of abdominal stab wounds in adults" and "Initial evaluation and management of abdominal gunshot wounds in adults".)

MECHANISM OF INJURY — The approach to the patient differs in many respects depending upon the mechanism of injury (ie, blunt versus penetrating). Blunt abdominal trauma can result in diffuse arterial injury while injuries related to penetrating mechanisms occur along the trajectory of the projectile(s). But whereas a knife will only cause direct tissue injury to the location(s) through which it has traveled, gunshot wounds can also cause a significant blast effect in the surrounding tissues.

Blunt injury to the abdominal aorta is much less common compared with blunt injury to the thoracic aorta, occurring in <0.1 percent of blunt injury patients [1]. Blunt injuries to the aorta may arise from compression between a seat belt and the spinal column (ie, seat belt aorta), which may be associated with other compression injuries (ie, seat belt syndrome) such as vertebral (Chance) fracture, solid organ (kidney, spleen), intestinal or pancreatic injuries, and abdominal wall injury (rectus abdominis rupture, abdominal wall disruption) [2].

Injury to the duodenum or pancreas can be also result in injuries to the superior mesenteric artery, superior mesenteric vein, inferior vena cava, or portal vein, particularly in the setting of penetrating trauma. Blunt mechanisms can result in intimal injuries to these vessels but rarely result in full-thickness injury or transection.

Penetrating injuries to the solid organs (ie, spleen, liver, and kidneys) can significantly destroy the major arterial supply and venous drainage. Blunt forces cause vascular injuries usually by stretching of the arteries causing intimal tears, with larger tears at risk for thrombosis and/or embolization downstream to the end organ. However, this is rare, occurring more commonly with the renal arteries. The vasculature within solid organs can be significantly disrupted by either mechanism, producing significant lacerations, pseudoaneurysms, or arteriovenous (AV) fistulas.

Pelvic fracture can be associated with iliac vessel injury with potential bleeding from branches of the internal iliac arteries and veins. However, bleeding causing hemodynamic instability in the setting of pelvic fracture is most commonly due to hemorrhage from the pelvic venous plexus. Transpelvic gunshot wounds can cause partial- or full-thickness injuries to the aortoiliac vessels depending upon the trajectory and blast effect. Contamination from associated rectal injuries complicates repair options.

CLINICAL FEATURES AND DIAGNOSIS

Initial findings — The clinical features associated with abdominal vascular injury are generally nonspecific and can include abdominal distention/pain, back/flank pain, signs of end-organ ischemia (eg, abdominal pain), or signs of ongoing blood loss (eg, hypotension, tachycardia, diaphoresis).

Abdominal distention related to blood loss into the abdominal cavity (ie, hemoperitoneum) from vascular injury is usually associated with hemodynamic instability. Findings of abdominal bruising (eg, seat belt sign), flank bruising (Grey-Turner sign) or scrotal ecchymosis are also nonspecific. Seat belt sign may be associated with "seat belt aorta," with aortic injury that can range from intimal tear to aortic rupture [2].

Flank or scrotal ecchymosis may indicate retroperitoneal bleeding. If retroperitoneal injury is associated with violation of the retroperitoneum such as with penetrating injury, significant hemorrhage will freely enter into the peritoneal cavity, rapidly leading to shock. Blunt injuries often remain contained in the retroperitoneum, but free anterior rupture can also occur. (See "Overview of the diagnosis and initial management of traumatic retroperitoneal injury".)

Minor intimal injury or low-grade solid organ parenchymal injury is not appreciated on clinical examination, but a high degree of suspicion based on mechanism of injury and physical exam may provide clues to its presence. As examples, splenic or hepatic injury may be suspected, depending on the side impacted in motor vehicle accident, and diminished or absent femoral pulses or scrotal hematoma can suggest bleeding from the pelvis. Such findings warrant further investigation.

A diagnosis of abdominal vascular injury is typically heralded by finding free fluid on focused assessment with sonography for trauma (FAST) in the emergency department. However, injuries limited to the retroperitoneum have no or only a small amount of free blood in the intraperitoneal cavity. Significant retroperitoneal venous injuries, such those involving the retrohepatic inferior vena cava, can be subtle, with patients presenting initially with no signs or only with transient hypotension that is responsive to resuscitation. Such patients are at high risk for sudden cardiovascular collapse.

In hemodynamically unstable patients, the type and location of abdominal vascular injury is definitively determined in the operating room in the context of damage control surgery. For hemodynamically stable patients, advanced vascular imaging is usually needed to confirm suspected vascular injury. (See 'Abdominal/retroperitoneal exploration' below and 'Advanced vascular imaging' below.)

Delayed presentations — The incidence and timing of delayed presentations are unknown, as these are overall rare. Subtle injury to the abdominal aorta can be asymptomatic and found incidentally on admission imaging. Traumatic intimal tears can manifest as intimal flaps, which can be complicated by thromboembolism and distal ischemia to extremities. (See 'Hemodynamically stable' below and "Embolism to the lower extremities".)

Unless an injury to the superior mesenteric artery has caused complete occlusion, mesenteric ischemia does not typically present acutely. Delayed presentations may be related to thrombosis or progression of a dissection. (See "Overview of intestinal ischemia in adults" and "Acute mesenteric arterial occlusion" and "Mesenteric venous thrombosis in adults".)

Advanced vascular imaging — Suspected abdominal vascular injury in a hemodynamically stable patient requires advanced vascular imaging. It is not uncommon to need more than one imaging modality to diagnose abdominal vascular injury. The choice depends upon the patient's clinical condition, physical examination findings, and availability.

Computed tomographic (CT) angiography with intravascular contrast is widely available and the most sensitive initial study to evaluate for abdominal vascular injury in the hemodynamically stable patient [3]. CT angiography relies on contrast extravasation to demonstrate active bleeding. Thus, abdominal vascular injury cannot be reliably ruled out without the use of contrast. CT angiography has a very low risk for renal toxicity and should generally not be withheld if there is a significant risk of detecting abdominal vascular injury [4]. Surveillance of vascular injuries can be safely performed using repeat CT angiography within 24 to 72 hours. If iodinated contrast cannot be safely administered (eg, severe allergy, renal dysfunction) and noncontrast CT is performed, vascular injury may be suspected if hematoma is seen in the area of concern.

It is important to remember that patients with potentially significant vascular injury who appear hemodynamically stable and who are taken for CT angiography are at high risk for rapid hemodynamic decompensation. A decision to proceed to the CT scanner depends upon resources, time, and distance required to travel to the scanner. At the very least, placing a common femoral arterial catheter for more sensitive hemodynamic monitoring prior to leaving the resuscitation suite is wise. An additional benefit to this practice is the ability to rapidly upsize the arterial catheter for resuscitative endovascular balloon occlusion of the aorta (REBOA). In institutions where REBOA is part of clinical practice, the catheter may be inserted prior to CT, allowing for rapid balloon inflation in the event of hemodynamic collapse. (See 'Role of REBOA' below.)

Conventional catheter-based aortography, which has been used for decades to identify vascular injury, has certain advantages over CT angiography. Aortography is a dynamic study permitting direct visualization of flow through the vessels in real time, particularly in areas of injury causing potential stenosis. In comparison, CT angiography is a static study and represents the presence of contrast at one point in time (or several, depending on phases). The contrast column and visualization of vasculature depends upon cardiac output, contrast concentration, and the timing of the scan. The presence of contrast above and below an area of injury on CT angiography does not guarantee a lesion is not flow-limiting.

Catheter-based aortography also allows the option for treatment once a diagnosis has been made. Aortography can be performed through common femoral, brachial, or radial access depending upon the location of the suspected injury and anticipated ease of access.

Aortography unfortunately requires a large contrast load and results in increased radiation exposure to the operator, staff, and patient. Further disadvantages to conventional catheter-based angiography include the inability to distinguish small intimal tears or lesions (more likely to be seen with CT angiography) that would prompt medical therapies and surveillance, rather than intervention. Such minimal injuries are more likely to be missed if imaging quality is suboptimal; some portable C-arm units are inferior to fixed, high-resolution fluoroscopy units in many anatomic areas.

Intravascular ultrasound (IVUS) is most sensitive for detecting lesions within the vessel lumen (image 1) as all layers of the vessel can be seen. IVUS is found to be more sensitive than CT angiography or conventional catheter-based angiography for identifying these lesions [5]. IVUS is very useful for diagnosing aortic injury and aiding stent-graft placement [6], particularly if a CT angiogram was not performed prior to intervention.

Duplex ultrasound for emergency diagnosis of abdominal aortic injury is not common, and limitations are largely due to patient anatomy and operator-dependent expertise in abdominal ultrasound imaging, as well as availability.

Vascular injury grading — The overall severity of injury is reflected in the abdominal vascular injury scale (table 1). The injury grades correlate with increasing morbidity and mortality, which are lower for smaller vessels, and for venous injury compared to arterial injuries of the same size.

The management of a specific arterial injury depends on the extent of the damage to the vessel. Injury grading is best illustrated for blunt thoracic aortic injury [7,8]. Such a scheme can be extended to serve as a framework for managing other arterial injuries, particularly the abdominal aorta, but possibly others as well. (See "Clinical features and diagnosis of blunt thoracic aortic injury".)

●Type I: Intimal injury

●Type II: Intramural hematoma

●Type III: Pseudoaneurysm

●Type IV: Rupture (eg, periaortic hematoma, free rupture)

Minimal injuries, which have become more prevalent with the use of high-resolution CT angiography, include isolated intimal (type I) defects without extravasation.

Abdominal aortic injuries can be classified by anatomic zone, which is also used to designate placement of resuscitative endovascular balloon occlusion of the aorta (figure 1) [9]:

●Zone I: from the diaphragm to the superior mesenteric artery

●Zone II: from the superior mesenteric artery to the renal arteries

●Zone III: below the renal arteries to the bifurcation

APPROACH TO MANAGEMENT

Hemodynamically unstable — Hemodynamically unstable patients who are at high risk for major abdominal vascular injury should be taken to a hybrid operating room, or alternatively, an operating room equipped with a radiolucent imaging table and vascular C-arm to maximize the options for managing the injury.

Role of REBOA — The role of resuscitative endovascular balloon occlusion of the aorta (REBOA) in patients with abdominal hemorrhage and hemodynamic instability is one of temporization and augmentation, providing time for thoughtful, prompt intervention and treatment. (See "Endovascular methods for aortic control in trauma".)

In the event of arrest from hemorrhage from a subdiaphragmatic source, REBOA can be used in place of resuscitative thoracotomy and aortic cross-clamping. REBOA is contraindicated when there is high suspicion for thoracic aortic injury. Clinical investigations of REBOA suggest a potential survival benefit, particularly in patients who are hypotensive but not yet in cardiac arrest [10]. However, complications from REBOA are significant and can include vascular injury, balloon rupture and loss of hemorrhage control, and distal ischemia, which can result in amputation [11]. Guidewires and catheters, when placed blindly in the resuscitation area, have the potential to migrate out of a large arterial injury [12]. Tactile feedback and imaging help determine if this occurs. The duration of occlusion, systemic complications, and the role of intermittent or partial aortic occlusion are some of the ongoing investigations. The precise role of REBOA has yet to be elucidated.

In patients with hemodynamic instability, REBOA can be used to provide proximal control prior to or during abdominal exploration, or as an adjunct to pelvic stabilization, pelvic packing, and/or angioembolization. The balloon can be inserted and inflated in zone I at the distal thoracic aorta (image 2) for presumed abdominal injury and in zone III at the aortic bifurcation (image 3) for patients for patients with pelvic or junctional bleeding (ie, groin region) [13]. The ability to perform this procedure at the bedside in the resuscitation area is one of its greatest advantages as an adjunct to other hemorrhage control measures. Another distinct advantage is the ability to obtain access and achieve aortic control early in the shock phase, ideally prior to the onset of arrest or irreversible shock.

Abdominal/retroperitoneal exploration — For hemodynamically unstable patients, abdominal exploration is performed in the context of damage control surgery, and the goals are to first contain hemorrhage, limit contamination, and maintain flow to vital organs and the extremities (ie, temporary shunting as needed).

Patient preparation should include the abdomen and both groins to near-circumferential mid-thigh. Midline incisions should stop proximal to the pubic symphysis in the event that a femoral-femoral bypass is required to revascularize the lower extremity. Once the abdomen is opened, bleeding due to intra-abdominal vascular injury is systematically explored following initial packing procedures. Damage control principles with vascular shunting are warranted in patients with complete physiologic devastation and competing injuries, and should be considered for any vascular injury that can accommodate a shunt or temporary stent-graft, including the aorta, mesenteric, and iliofemoral arteries as long as patency and distal perfusion can be monitored [14]. Prior to repair of specific arterial injuries, any shunts that have been placed are removed once appropriate exposure and proximal and distal control have been achieved. Management of specifically identified injuries is discussed below. (See "Overview of damage control surgery and resuscitation in patients sustaining severe injury", section on 'Damage control laparotomy' and 'Repair of specific vascular injuries' below.)

Whether to explore the retroperitoneum depends upon the mechanism of injury and the affected retroperitoneal zone (figure 2). (see "Overview of the diagnosis and initial management of traumatic retroperitoneal injury", section on 'Retroperitoneal zones' and "Overview of the diagnosis and initial management of traumatic retroperitoneal injury", section on 'Surgical approach by zone'):

In summary:

●Hematoma in retroperitoneal zone I, which contains the aorta, inferior vena cava, celiac axis, and the origin of the mesenteric arteries, should be explored.

●Hematoma in retroperitoneal zone II (contains the renal vessels and renal parenchyma) and zone III (contains the iliac vessels) hematomas due to blunt mechanisms should be explored only if the hematoma is expanding, pulsatile, or there is evidence of distal ischemia (eg, no palpable femoral pulse). In general, penetrating mechanisms should be explored if the hematoma is expanding. Some isolated penetrating injuries to the kidneys can be managed nonoperatively if the patient is stable and the hematoma is not expanding.

●Hematoma in retroperitoneal zone III due to penetrating mechanisms should also be explored [15].

In the setting of contamination, temporary endovascular repair should at least be considered for injuries requiring repair with synthetic grafts, even if complete exposure and hemorrhage control has already occurred. This includes aortoiliac and mesenteric injury.

An alternative to exploration for vascular injury in the setting of nonexpanding retroperitoneal hematoma in all zones is arteriography, with the understanding that while this approach can be used to diagnose and treat arterial injury, major venous injuries will not be diagnosed. This is most efficiently achieved in the operating room where the patient in undergoing exploration (ie, hybrid room, or fluoroscopy with C-arm). In this manner, arteriography can be performed immediately after the damage control operation without delay or patient transport.

Hemodynamically stable — Hemodynamically stable patients with vascular injury should be evaluated for treatment based on the degree of injury and prognosis (eg, intimal tear, small pseudoaneurysm). When abdominal vascular injury is not life-threatening (ie, the injury is not causing severe hemorrhage or ischemia), and other injuries are more significant and require urgent treatment, management of the vascular injury can be deferred. Intimal tears can be treated with antiplatelet therapy or anticoagulation if deemed significant. Frequent assessment of distal perfusion and imaging surveillance is recommended. Medical management of vascular injury in the setting of severe multiple trauma requires consideration of competing injuries (eg, traumatic brain injury), which may contraindicate antithrombotic therapy. The risks and benefits of antithrombotic agents should involve multidisciplinary discussion.

In a review of the National Trauma Data Bank that included 436 patients with blunt abdominal aortic injury, 90 percent were managed nonoperatively. Low-grade abdominal aortic injuries can be managed with antiplatelet agents, anti-impulse therapy (eg, beta blockade), and imaging surveillance (serial computed tomographic [CT] angiography, ideally) [16]. Any progression of the flap, evidence of thrombosis, significant luminal narrowing, or distal thromboembolism should prompt intervention.

REPAIR OF SPECIFIC VASCULAR INJURIES

Abdominal aorta — Management of aortic injury varies, and risk of death increases with increasing injury severity. In a review of the National Trauma Data Bank of 436 patients among those who underwent aortic repair, 69 percent underwent endovascular repair, with the remainder undergoing open aortic repair and two extra-anatomic bypasses. Reports of endovascular stent placement in cases of aortic injuries have increased in frequency, similar to those of blunt thoracic aortic injury. Several reports have demonstrated its efficacy in both blunt and penetrating trauma [1,17,18].

Identification of aortic injuries during trauma exploration is possible using proximal control, either with an aortic cross-clamp, sponge stick, manual compression above the celiac artery [19], or with resuscitative endovascular balloon occlusion of the aorta (REBOA).

Exposure of the aorta (picture 1) above the renal arteries can be accomplished using a left medial visceral rotation with division of the left crus of the diaphragm (see "Overview of the diagnosis and initial management of traumatic retroperitoneal injury", section on 'Left medial visceral rotation'). A Satinsky or other side-biting clamp can be placed across the injury and used for proximal and distal control; alternatively, if REBOA was performed prior to exploration, the balloon may be deflated or inflated as needed for identification of injury and proximal control.

Exposure to the infrarenal aorta is accomplished by packing the small bowel into the right upper quadrant, lifting the transverse mesocolon superiorly, then opening the ligament of Treitz and dissecting into the retroperitoneum. A vein retractor can be used to mobilize the renal vein superiorly to clamp the aorta just below the renal arteries. Alternatively, aortic balloon occlusion can be used and the balloon repositioned as needed with the position confirmed with palpation and visual inspection.

Small defects or injuries in the aortic wall can be repaired primarily with polypropylene (eg, Prolene) suture while larger defects may require patching with autologous or synthetic material. Significant defects to the aorta may require complete interposition repair with a synthetic graft. Attention should be paid to the diameter of the final lumen to ensure that minimal to no narrowing has occurred. Large changes in the caliber of the aorta can result in dissection flaps and/or thrombus formation, as well as increased tension on the anastomosis.

Injuries to this infrarenal aorta can be repaired primarily with synthetic graft materials [20] or may be amenable to endovascular stent repair if there is an acceptable proximal landing zone below the main renal arteries (ie, not in close proximity to origins of visceral vessels) (image 4). Advantages of endovascular repair include management of injuries that are difficult to expose by conventional means, and the ability to fix the vessel from within, which is helpful in cases with gross contamination, which can jeopardize aortic grafts due to risk of infection.

Rarely, an aortic injury occurs where the proximal and distal landing zones place branch vessels at risk, and while a stent-graft is an excellent and minimally invasive treatment option, fenestrated and branched aortic stent-grafts are generally not available in emergency circumstances since these are generally custom-designed devices. The chimney technique, in which the branch vessels are stented along with the aorta, may be an option for select patients but also requires increased expertise and time to perform.

Mesenteric arteries

Celiac artery and branches — Injury to the celiac artery is uncommon but challenging in terms of exposure and treatment. Small lesions noted on computed tomographic (CT) angiography without hematoma or thrombosis can be managed with antiplatelet therapy and surveillance. Larger lesions at the origin seen on CT angiography can be treated with endovascular therapy if a guidewire appropriately sized for the device platform can be passed beyond the injury. Patients who have significant hemorrhage due to celiac injury at the time of exploration can should be treated with primary repair, if possible, but most patients tolerate celiac artery ligation if needed [21]. Cholecystectomy should be performed if the celiac artery is ligated.

Injury to the splenic artery causing hemodynamic collapse usually occurs at the splenic hilum, and treatment typically involves splenectomy. While minor arterial injury incidentally identified on imaging in hemodynamically stable patients is very rare, these can be managed according to severity. As an example, a minimal dissection flap might be observed, whereas a larger flap may be amenable to endovascular treatment. For splenic infarction, splenectomy is warranted with ligation of the artery proximal to the site of injury. (See "Management of splenic injury in the adult trauma patient" and "Surgical management of splenic injury in the adult trauma patient".)

Superior mesenteric artery — Injury to the superior mesenteric artery (SMA) carries significant morbidity as loss of perfusion to small and large bowel can be fatal. SMA injuries can be classified by segments corresponding to risk of ischemia and subsequent bowel affected [22].

The proximal SMA can be identified using a left medial visceral rotation or can be exposed at the root of the mesentery, while distal SMA injuries require mobilization of the duodenum off the SMA, or from the left by dividing the ligament of Treitz. Ligation of the SMA is not well tolerated and should be avoided if possible. (See "Overview of the diagnosis and initial management of traumatic retroperitoneal injury", section on 'Right medial visceral rotation' and "Overview of the diagnosis and initial management of traumatic retroperitoneal injury", section on 'Left medial visceral rotation'.)

Primary repair can be performed using simple closure, patch, or interposition grafts, and shunting is an option prior to those treatments [23,24]. Aorto-SMA bypass can be considered for proximal injuries not amenable to repair, and for distal injuries, which are not amenable to stent grafting. For proximal SMA injuries, endovascular stenting can be accomplished using either an antegrade or retrograde approach (picture 2 and image 5).

Because these injuries are usually identified during abdominal exploration, the distal SMA is available for sheath placement and placement of a stent retrograde into the proximal SMA. In the setting of gastrointestinal contamination, antegrade SMA stenting using a femoral or brachial approach avoids making an arteriotomy. Stenting distal SMA injuries is not ideal due to the origins of large branch vessels supplying the bowel (image 5).

The patency of SMA stents in the setting of injury is unknown, but antiplatelet agents should be used, and postoperative surveillance is mandatory. (See 'Surveillance following stenting/stent-grafting' below.)

Inferior mesenteric artery — Injury to the inferior mesenteric artery (IMA) is usually treated with immediate ligation, which is most often well tolerated due to extensive collaterals. However, in patients with atherosclerotic disease in the SMA, ischemia may occur if the IMA contributes significantly to perfusion; this may be evident with the finding of a large-diameter IMA.

Renal arteries — Major renal vascular injuries (renal artery and/or renal vein) are described as active bleeding typically from severe blunt or penetrating injury, or as devascularization injuries (no active bleeding) (image 6), typically from blunt injury forces causing renal artery stretch and dissection, which can lead to thrombosis. (See "Management of blunt and penetrating renal trauma".)

Active bleeding — Treatment of renal artery injury discovered at laparotomy is largely dependent on physiology. Renal vascular injuries with active bleeding may be the source of hemodynamic instability necessitating retroperitoneal exploration. Primary repair of renal arteries is feasible unless luminal narrowing results, in which case patch repair or interposition graft is preferred. The segmental renal arteries are end arteries, and their ligation will result in distal renal ischemia (image 7 and image 8); however, ligation is preferred over nephrectomy. While every effort should be made to repair the kidney, patients in extremis with a functional contralateral kidney may require nephrectomy.

To expose the kidney, dissection of the lateral peritoneum and medial rotation of viscera will expose Gerota's fascia, which should be opened laterally to deliver the kidney. Early renal vascular control proximal to the site of injury before renal exploration can aid repair of renal artery injuries. Midline vascular control with isolation of the main renal vessels has been advocated to reduce unnecessary nephrectomy [25-27]. While this is desirable, proximal control at the midline is not always possible in the patient with massive bleeding. Mobilizing the kidney from its lateral aspect and lifting it medially to obtain control of the renal vessels at the hilum is a rapid maneuver that avoids central dissection (picture 3) [28-31]. (See "Overview of the diagnosis and initial management of traumatic retroperitoneal injury", section on 'Left medial visceral rotation' and "Overview of the diagnosis and initial management of traumatic retroperitoneal injury", section on 'Right medial visceral rotation'.)

Devascularization injury — Patients with renal artery injury identified on CT angiography may be candidates for endovascular intervention [32,33] depending on the nature of the injury and physiologic status and time since original injury.

Small intimal flaps or dissections may be treated with antiplatelet therapy. Surveillance of the lesion and renal function is continued as long as there is no evidence of thrombus or significant luminal narrowing. Dissection flaps can be dynamic; thus, assurance of renal perfusion and stability or resolution of the lesion is critical.

In the case of blunt injury, complete occlusion of the renal artery is usually due to a large flap with subsequent thrombosis, which may be amenable to mechanical and/or pharmacologic thrombolysis with treatment of the offending flap with grafting. Rapid identification of renal ischemia is required if renal salvage is to be attempted.

Surgery for devascularization injuries is limited to selected indications such as bilateral devascularization or devascularization of a solitary kidney. Main renal artery occlusion-type devascularization injuries (eg, dissection) may be amenable to endovascular intervention using recanalization techniques [34-36].

Other visceral arteries — Pancreatic branches can be sacrificed, given that the foregut is rich in collaterals and ischemia is rare. Injuries to the hepatic and gastroduodenal artery, if minor, should be treated conservatively with surveillance of both lesion and distal perfusion, while larger injuries can be treated with endovascular embolization, or repaired at the time of exploration.

Iliac arteries — Injuries to the iliac arteries are life-threatening if transmural, or limb-threatening if severely flow-limiting.

Iliac artery exposure can be accomplished by eviscerating the small bowel to the right upper quadrant and exposing the proximal common iliac arteries with entry into the retroperitoneum. The ureters should be identified to avoid injury. Proximal vascular control can be achieved with clamps, vessel loops, or balloon occlusion through the injury or remotely through the common femoral artery. Distal external iliac artery injuries may require dissection and distal control by dividing the inguinal ligament for optimal exposure. Shunting vascular injuries in patients with complete physiologic devastation and competing injuries is warranted [14] so long as patency and distal perfusion is monitored in short intervals. For injuries to the common iliac arteries, temporary balloon control (picture 4) followed by stent-grafting is an option, particularly when there is abdominal contamination.

When common iliac artery injuries have caused complete transection and loss of significant length, interposition grafts can be used for repair. Reversed great saphenous vein is usually inadequate in caliber to be a substitute for the common iliac, and spliced veins are too time consuming. For iliac vein interposition, the femoral vein is a more appropriate size match and can be time consuming to harvest but can be used when the patient's physiology allows. However, most patients with this injury type are in profound shock or may have other serious injuries, necessitating a damage control approach to revascularization. A biologic or polytetrafluoroethylene (PTFE; eg, Gore-Tex) graft, covered with omentum, is expedient. Deep femoral vein becomes a better option when returning to operating room for definitive repair, particularly if a field has become contaminated. Biologic grafts such as bovine carotid (eg, Artegraft) or cadaveric vein (eg, CryoVein) are other options. There are no data regarding long-term patency of these biologics.

For injuries to the external iliac arteries, stent-grafts are adequate if short in length. Stenting near the inguinal ligament increases the risk of stent failure due to the range of motion in that area but is less of an issue with self-expanding grafts compared with balloon-expandable stents. Options for open repair include the above grafts, as well as ligation of the distal ipsilateral hypogastric and primary anastomosis to the native external iliac artery (picture 5). Patch repairs of both common and external iliac arteries are best accomplished with native vein.

Ligation or embolization of the proximal internal iliac arteries is acceptable in cases of life-threatening bleeding from these vessels [37]. While the pelvic collateral circulation is robust and ischemic complications such as gluteal ischemia are rare in the setting of superselective embolization [38], recommendations for postoperative care include vigilant monitoring for buttock compartment syndrome and development of decubitus ulcers.

Abdominal venous injury — Injury to the major venous structures in the abdomen is rare but causes significant morbidity if not controlled and treated quickly.

Mesenteric and portal veins — Mesenteric and portal venous are uncommon, and little evidence is available to guide best practices in these scenarios.

Portal vein and superior mesenteric vein (SMV) bleeding usually results in intraperitoneal bleeding, and exploration of the area is challenging in the face of a large expanding hematoma. Proximal control with a Pringle maneuver (figure 3) followed by dissection of portal structures should be performed quickly. Additional reduction in inflow reduction can be accomplished with aortic clamping or balloon occlusion for patients in extremis. More distal SMV injuries can be accessed with a Kocher maneuver, right medial visceral rotation, or division of the neck of the pancreas [39]. (See "Overview of the diagnosis and initial management of traumatic retroperitoneal injury", section on 'Right medial visceral rotation'.)

In extreme cases when hemostasis cannot be achieved, injuries to the PV or SMV can be ligated after confirmation of a patent hepatic artery. SMV is highly morbid due to the visceral ischemia that ensues with outflow obstruction. Splanchnic hypervolemia may also occur, leading to cardiovascular collapse. Reconstruction of the portal vein or SMV is recommended as soon as the patient's condition permits.

Repair of the SMV can be performed primarily, with patch, or with interposition graft. A key to patency of this vessel to ensure the repair lays within the abdomen without torsion or tension. A ringed PTFE graft is ideal, although using a synthetic material in the setting of abdominal contamination is not recommended. Biologics (eg, Artegraft) that have a thicker wall than autologous vein may be useful. Femoral vein interposition grafts can be life-saving in the setting of pancreatic and/or bowel injuries and should be considered before prosthetic materials are used in these scenarios [40].

Regardless of the repair type, ongoing assessment of bowel viability is warranted, as well as imaging for surveillance, preferably by duplex ultrasound. (See 'Follow-up care' below and 'Surveillance following stenting/stent-grafting' below.)

Inferior vena cava — Inferior vena cava (IVC) injury is extremely morbid and particularly challenging to manage as it is not usually identified until the time of exploration.

Surgical exposure to the suprarenal IVC is accomplished by performing a Kocher maneuver with duodenal mobilization. The infrarenal IVC can be examined using a right-sided medial visceral rotation (see "Overview of the diagnosis and initial management of traumatic retroperitoneal injury", section on 'Right medial visceral rotation'). Hemostatic agents and gentle pressure or some simple sutures can be effective as this is a low-pressure vessel. For large injuries, care must be taken to prevent significant luminal narrowing leading to thromboembolic events, including complete occlusion. For patients in extremis, ligation of the infrarenal IVC can be considered. Postoperatively, bilateral lower extremity compression and elevation is required to reduce edema and severe sequelae such as compartment syndrome and venous hypertension.

Retrohepatic caval injuries, particularly those at the junction of the hepatic veins, are life-threatening if the defect is large. Proximal and distal control of the IVC can be difficult since the cava wall is thin. Taking down the falciform, right, and left triangular ligaments and eviscerating the liver medially allows complete exposure of this portion of the IVC.

Translational studies and isolated clinical reports suggest balloon occlusion of the IVC may be feasible for temporization of severe venous hemorrhage [41-44]. This option involves placement of a soft, long, compliant balloon at the site of injury. The sudden decrease in preload in the already hypovolemic patient is not likely to be tolerated without concomitant aortic occlusion and massive transfusion from sites in the upper extremities.

Total hepatic isolation can be achieved with a Pringle maneuver and placement of an occlusion balloon in the IVC (picture 6) and REBOA at zone I. Preload reduction may be lethal without aggressive proximal transfusion and/or vasopressor use.

Open repair of hepatic vein injuries is easiest if primary repair can be accomplished without significant reduction in luminal diameter. Stent repair is a challenge in this area, especially when near the origin of the hepatic veins, but several case reports have described successful outcomes in select cases [45-47].

Iliac vein — Iliac vein injuries are unforgiving, and patients usually present in shock if the injury is transmural. Rapid vascular control with sponge stick or balloon catheter is ideal for these injuries.

Ligation is always an option if physiology dictates a damage control procedure, with imperative postoperative extremity compression and elevation. Shunting, primary repair, patch, or interposition grafting are all options for these injuries depending on degree of injury [48].

Due to the low-flow state of the venous system, anticoagulation after repair is indicated if permissible. Stent-grafting these injuries is an option, although the majority of cases are identified in the operating room (OR) where immediate surgical repair or ligation is usually needed.

REBOA placed in zone III is effective for reducing hemorrhage from pelvic venous plexus hemorrhage associated with pelvic fracture [49] and has been demonstrated to be effective in reducing hemorrhage from major veins in animal models [43].

FOLLOW-UP CARE

Abdominal compartment syndrome and open abdomen management — Any emergent vascular injury repair to the abdominal vessels and in particular the visceral vessels requires temporary abdominal closure and a second look. The abdomen should be reexplored to evaluate bowel perfusion and the integrity of the repairs within 24 hours. Depending on the nature of the injury and repair, postoperative care may include anticoagulation. Thus, patients with an open abdomen are prone to further bleeding episodes. Thus, diligent monitoring is essential not only for clinical signs of failed repair and ischemia, but bleeding as well. (See "Abdominal compartment syndrome in adults" and "Management of the open abdomen in adults".)

Surveillance following stenting/stent-grafting — Following aortic repair, no high-level evidence exists for interval and duration of surveillance imaging in trauma patients treated with stents or aortic stent-grafting. Follow-up for visceral and iliac stenting is similar to that associated with nontraumatic indications. (See "Surgical and endovascular techniques for mesenteric revascularization", section on 'Postoperative imaging and surveillance' and "Endovascular techniques for lower extremity revascularization", section on 'Surveillance after endovascular interventions'.)

Recommendations for aortic stent-grafts are extrapolated from other indications and include computed tomography (CT) angiogram at 1, 3, 6, and 12 months from intervention [50]. Surveillance can be extended after this time to 12 to 24 months. Risks of radiation exposure and contrast load should be kept in mind when planning any endovascular treatment requiring CT angiography surveillance. Duplex imaging may be an acceptable alternative, but visualization of stent complications requiring reintervention such as fracture or small endoleaks can be challenging and based on operator expertise.

MORBIDITY AND MORTALITY — Mortality rates for abdominal vascular injury vary depending upon the vessels involved and associated injuries. Multiple studies have demonstrated an advantage for endovascular approaches to hemorrhage control and blood vessel injury [51,52]. In a study from the American College of Surgeons National Trauma Data Bank (NTDB), outcomes were compared between matched patients who underwent endovascular and open procedures [51]. Patients undergoing endovascular procedures had significantly lower in-hospital mortality (12.9 versus 22.4 percent) and a decreased rate of sepsis after intervention (7.5 versus 5.4 percent). During the study period (2002 to 2010), the rate of endovascular stent-graft use among trauma patients increased significantly. The most dramatic uptake in use occurred among injured vessels located at sites associated with anatomically challenging exposures such as iliac arteries.

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: General issues of trauma management in adults" and "Society guideline links: Traumatic abdominal and non-genitourinary retroperitoneal injury".)

SUMMARY AND RECOMMENDATIONS

●Clinical features associated with abdominal vascular injury are generally nonspecific (eg, abdominal distention/pain, back/flank pain, hypotension, tachycardia). A suspected diagnosis of abdominal vascular injury is made or confirmed either in the operating room in hemodynamically unstable patients in the context of damage control surgery, or with advanced vascular imaging (typically computed tomographic [CT] angiography) in hemodynamically stable patients. Delayed presentations associated with traumatic intimal tears that progress include development of signs of acute mesenteric ischemia or distal thromboembolism. (See 'Clinical features and diagnosis' above.)

●Resuscitative endovascular balloon occlusion of the aorta (REBOA) may improve survival of hemodynamically unstable patients with noncompressible hemorrhage in the abdomen by providing a window of time that allows for resuscitation and intervention. Placement of these devices is limited to those with appropriate training. Complications can include REBOA balloon rupture with loss of vascular control, further or new vascular injury, and end-organ ischemia, which in the lower extremity can lead to amputation. (See 'Role of REBOA' above and "Endovascular methods for aortic control in trauma".)

●For hemodynamically unstable patients, abdominal exploration is performed in the context of damage control surgery, with the first goal being to contain life-threatening hemorrhage. The vascular injury takes priority over other injuries. Once bleeding is under control, other injuries can be attended to. (See 'Approach to management' above and "Overview of damage control surgery and resuscitation in patients sustaining severe injury".)

●Abdominal exploration and the management of retroperitoneal hematoma by zone of injury in the context of damage control is summarized as follows (figure 2). (See 'Abdominal/retroperitoneal exploration' above and "Overview of the diagnosis and initial management of traumatic retroperitoneal injury", section on 'Surgical approach by zone'.)

•Hematoma in zone I, which contains the aorta, inferior vena cava, celiac axis, and the origin of the mesenteric arteries, should be explored.

•Hematomas due to blunt mechanisms in zone II (contains the renal vessels and renal parenchyma) and zone III (contains the iliac vessels) should be explored only if expanding, pulsatile, or there is evidence of distal ischemia (eg, no palpable femoral pulse).

•In general, penetrating mechanisms should be explored if zone II or zone III hematoma is expanding. Some isolated penetrating injuries to the kidneys can be managed nonoperatively if the patient is stable and the hematoma is not expanding.

●Abdominal vascular injuries were traditionally managed using open surgical techniques; however, use of endovascular methods for treating traumatic vascular injury has increased steadily. Endovascular approaches to hemorrhage control and repair of abdominal vascular injury are associated with lower perioperative mortality. (See 'Introduction' above and 'Repair of specific vascular injuries' above.)

●Conservative nonoperative management of low-grade arterial injuries such as small intimal flaps that have not caused distal embolization is appropriate. Management includes antiplatelet therapy, anti-impulse therapy (eg, beta blockers), and surveillance, ideally with CT angiography. Prompt intervention is indicated for any evidence of progression, thrombus formation, significant luminal narrowing, or distal thromboembolism. (See 'Hemodynamically stable' above.)

●The repair of specific vascular injuries depends on the extent of the injury, its location, and the nature of associated injuries, and may involve primary repair, patch repair, interposition grafting, or endovascular stent placement. In the setting of gastrointestinal contamination, biologic graft material is preferred. Techniques for the arterial or venous repair at the various anatomic sites are reviewed above. (See 'Repair of specific vascular injuries' above.)