Trauma is the leading cause of death in patients under the age of 44 in the United States. North American trauma centers have an incidence of penetrating trauma of 35% as compared with 5% to 8% in Europe, the difference being ex- plained by the higher rate of weapon-related crimes in North America. The treatment of trau- matic vascular injuries today is based on prin- ciples gained during the military conflicts of the 20th century; previously treatment of vascular injuries was limited to the staunching of bleed- ing by cautery, compression, and ligature. The concept of repair was documented in anecdotal reports only. William Hunter in 1759 recounts the first successful vascular repair on a brachial artery using a farrier’s stitch.
Reports of vein grafting were available in the early 20th century; however, these tech- niques were not suitable for the injuries en- countered during World War I, in which the amputation rate was noted to be 72.5%. In 1946 DeBakey and Simeone published a review of World War II experiences with vascular surgery.
They concluded that ligation was “of stern necessity,” required to control hemorrhage;
attempts at vascular repair were superior to ligation and led to an amputation rate of 49%.
The application of vessel reconstruction in the Korean War, despite the mean lag time of over 6 hours between injury and repair, reduced the lower limb amputation rate to 13% (Hughes, 1959); a comparable figure was achieved during the Vietnam War. The Vietnam Vascular Regis-
try was established during the Vietnam War;
surgeons were able to document and analyze the long-term management and outcome of vascu- lar trauma (Rich and Hughes, 1969). The significantly improved long-term results of vas- cular repair were attributed to faster evacuation of casualties within 3 hours of injury, thereby allowing surgeons to treat injuries that had pre- viously been otherwise fatal. Operations were performed by experienced surgeons using auto- logous vein grafts.
The rise of civilian trauma in the United States has resulted in surgeons becoming more adept and experienced at dealing with vascu- lar injuries (Mattox et al., 1989). Penetrating injuries have been the number one cause of vascular trauma in both urban and rural com- munities, whereas blunt trauma has accounted for approximately 50% of vascular injuries, most commonly secondary to road traffic accidents.
Regardless of the etiology of the vessel injury, the essential principles of treatment are emer- gency resuscitation at the scene, triage and rapid transport to an appropriate hospital, vig- orous resuscitation, diagnosis, and definitive surgery. Ideally, vascular injuries should be treated by surgeons with expertise in vascular reconstruction and trauma, in an environment with the necessary ancillary support services to allow the best results.
This chapter reviews the workup and treat- ment of traumatic vascular injuries involving the head and neck, chest, abdomen, and extrem-
Vascular Trauma
Kathleen J. Ozsvath, R. Clement Darling III, Laila Tabatabai, Sacha Hamdani, Alun H. Davies, and Meryl Davis
125
ities, and discusses the approach to iatrogenic injuries and the endovascular treatment of vas- cular injuries.
Mechanisms of Injury
Vascular injuries can be divided into penetrat- ing and blunt. Penetrating injuries include stab- bing and gunshot wounds. Stab wounds are usually clean with minimal soft tissue injury;
however, in the neck and upper limb concurrent nerve damage must also be suspected.
Gunshot wounds are classified according to the bullet velocity. Low velocity bullets have a velocity of less than 250 m/s, whereas 750 to 900 m/s represents the speed of high-velocity bullets. Low-velocity bullets injure the tissue through which they pass, whereas high-velocity bullets create a cavitational effect, thereby caus- ing a suctional effect contaminating the entire wound. If a high-velocity bullet strikes bone, there is extensive comminution with a large exit wound. Shotgun injuries particularly to a limb can cause vascular damage at several levels.
Bombs, mines, and rocket-propelled grenades produce complex injuries that frequently result in amputation.
Blunt vascular trauma is often caused by deceleration in road traffic accidents and is fre- quently associated with other injuries. Femoral shaft fractures and fracture dislocations of the knee carry a 10% to 40% incidence of vascular injury. It is important to realize that although the artery can remain intact, intimal damage with concomitant thrombosis risk can occur.
Blunt trauma to the upper limb is often asso- ciated with avulsion injuries to the brachial plexus. Extensive crush injuries to the limbs are associated with a poor prognosis due to soft tissue damage and reperfusion injury.
Iatrogenic injuries are increasing in inci- dence as a consequence of invasive procedures.
Cardiological and radiological catheterization cause between 60% and 76% of all iatrogenic injuries. Orthopedic procedures including joint replacements may cause vascular injury, com- monly to the external iliac, common femoral, or popliteal arteries. In such cases where iatrogenic arterial injury is suspected, expeditious referral to a vascular surgeon must be made.
Diagnosis
The clinical manifestations of vascular injury are divided into hard and soft signs (Table 11.1).
The management of penetrating limb trauma in the presence of one hard sign is exploration in the operating room. In blunt trauma, closed head injuries, spinal damage, and cervical and brachial plexus injuries may complicate the clinical findings; a careful neurological exami- nation is mandatory.
Clinical examination in blunt and complex penetrating trauma may be unreliable, and trauma centers advise early angiography. The role of duplex ultrasound in vascular trauma is less clear; currently it has a major role in the diagnosis of occult vascular injuries and in postoperative assessment. Doppler arterial pres- sure index (API) is a useful tool. It is the systolic arterial pressure in the injured extremity divided by the arterial pressure in a noninjured arm. A result of <0.90 has been found to have a sensitivity of 95% and specificity of 97% for major arterial injury (Johansen et al., 1991).
Once the diagnosis of major vascular injury has been made, the majority of patients require exploration and repair. The principles of emer- gency vascular repair are to control bleeding and prevent limb ischemia. Hemorrhage is usually apparent, but ischemia may be insidious and must be sought. Time is paramount; it is generally accepted that more than 6 to 8 hours of warm ischemia time makes limb survival unlikely. If there is significant concurrent nerve damage, then limb reconstruction may not be appropriate and amputation should be per- formed. The input of multidisciplinary teams is vital to ensure optimal treatment.
Table 11.1. The clinical manifestations of vascular injury are divided into hard and soft signs
Hard signs Soft signs
No pulse Hematoma (small)
Thrill or bruit History of bleeding at scene Active bleeding Hypotension
Hematoma (large/ Nerve damage expanding)
Distal ischemia
Vascular Injuries in the Neck
Wounds of major vessels are often lethal, and frequently these patients have multiple injuries.
This is particularly true in penetrating in- juries of the brachiocephalic vessels, where air- way compromise, hemorrhage, and neurological damage secondary to impaired brain blood flow may occur, along with associated injuries to the pharynx, esophagus, and brachial plexus.
In the neck penetrating trauma is more common than blunt trauma, although vascular injuries caused by blunt trauma can be more difficult to diagnose and treat. Blunt injuries include steering wheel injuries, deceleration forces, and crushing blows.
Injuries to the carotid artery occur in 6% of penetrating injuries to the neck and make up 22% of all vascular neck injuries, whereas 3% to 5% of carotid injuries are secondary to blunt trauma (Demetriades et al., 1996). The mortal- ity rate of patients with penetrating neck vas- cular trauma is 5% to 20%. Patients presenting with obvious signs of penetrating vascular injury (expanding hematoma, pulsatile bleed- ing) should be rapidly explored operatively.
Treatment of vascular injuries in the neck is based on dividing the neck into three zones:
zone I is 1 cm above the manubrium including the thoracic outlet, zone II extends from the upper limit of zone I to the angle of the man- dible, and zone III lies between the angle of the mandible and the base of the skull (Fig. 11.1).
Zone I injuries are best explored through a median sternotomy, which can then be extended superiorly along the anterior border of the ster- nocleidomastoid muscle as needed. Penetrating trauma to vessels in zone II can be approached directly for definitive repair. Zone III injuries can be difficult to access and sometimes require subluxation of the mandible or mandibular osteotomy. Patients with zone III asymptomatic, angiographically documented injuries are now being managed with endovascular stenting or embolization (Feliciano, 2001).
Arterial defects are repaired with primary repair, transposition, patch, or bypass. Patients found to have an acutely occluded carotid artery are anticoagulated in an effort to prevent clot propagation. Neurologically impaired patients with carotid injuries are aggressively treated surgically. Patients with small intimal defects
and dissections of the carotid artery who are otherwise stable may be followed with physical examination and follow-up duplex ultrasound, because these lesions may resolve without inter- vention. Venous injuries may be dealt with by ligation. In the unusual circumstance of both internal jugular veins having been damaged it is imperative that one vein be reconstructed.
Patients with blunt carotid artery injuries can be difficult to diagnose due to either other distracting injuries or altered mental status.
Carotid artery blunt injuries are associated with a high mortality and poor neurological out- comes in most patients.
Mechanisms of blunt carotid artery in- juries include hyperextension, direct injury, basilar skull fractures, and intraoral injuries.
Patients may present with carotid artery dissec- tions, thrombosis, pseudoaneurysms, carotid- cavernous sinus fistulas, or arterial disruption.
Carotid artery dissections and thrombosis are treated with anticoagulation. Cogbill et al.
(1994) reported that two thirds of patients with carotid dissections eventually have normal studies on follow-up, whereas one third pro- gress. Pseudoaneurysms may be treated surgi-
I II III
Figure 11.1. Treatment of vascular injuries in the neck is based on dividing the neck into three zones: zone I is 1 cm above the manubrium to include the thoracic outlet, zone II extends from the upper limit of zone I to the angle of the mandible, and zone III lies between the angle of the mandible and the base of the skull.
cally or radiologically depending on their size.
Carotid–cavernous sinus fistulas are generally treated by endovascular techniques. Complete disruption of the carotid artery is associated with a high mortality.
Injury to the vertebral arteries is rare. The anatomical location of the injury determines the best operative approach when intervention is required. Proximal vertebral artery exposure is performed by a transverse supraclavicular inci- sion or an anterior cervical incision. The cervi- cal vertebral artery is best approached through an incision along the anterior border of the ster- nocleidomastoid muscle, and can be extended to the posterior auricular area. Once the verte- bral artery takes its course from the C2 foramen and enters the skull, the exposure becomes very difficult. Ligation or occlusion of the vertebral artery is usually the treatment of choice. Per- cutaneous techniques have been successfully employed in managing arteriovenous fistulas, pseudoaneurysms, and occlusions (Halbach et al., 1993).
Thoracic Vascular Injuries
Thoracic vascular trauma constitutes approxi- mately 10% of vascular trauma (Bongard et al., 1990). Although penetrating trauma remains the most common etiology of thoracic vascular injuries, deceleration injuries and crush injuries can result in major thoracic vascular trauma.
Injuries to the vessels in the thoracic cavity can lead to rapid blood loss and hemodynamic collapse; many patients die before reaching the hospital. It is often more appropriate to bypass the nearest hospital and transfer the patient to a unit able to manage cardiothoracic problems.
These patients may require immediate treat- ment for tension pneumothorax or cardiac tam- ponade. Thoracotomy may be required as an emergency procedure and is usually carried out via a left anterolateral thoracotomy incision (which can be extended across the sternum) or a posterolateral thoracotomy. Access to carotid arteries and innominate artery can be obtained through a median sternotomy. Middle and distal subclavian artery injuries can be controlled with infra- and supraclavicular approaches.
Clinical findings suggesting thoracic injury include external evidence of severe chest
bruising, reduced or absent lower limb pulses, raised jugular venous pressure, and unex- plained hypotension. The chest radiograph may show a widened mediastinum, fracture of the first or second rib, hemothorax, and thoracic spine injury.
In stable patients the investigations of choice are chest radiographs (suggesting great vessel or aortic injury), spiral computed tomography (CT) with contrast, angiography, and trans- esophageal echocardiography.
The most common intrathoracic injury caused by deceleration involves disruption of the descending thoracic aorta at the isthmus.
Sudden death is common, and it is estimated that 90% die before reaching the hospital; of those who reach the hospital, 25% die within 24 hours.
Commonly the site of aortic disruption is distal to the left subclavian artery. Access is gained via a left posterior thoracotomy with cardiopulmonary bypass. The incidence of paraplegia is approximately 8%. Recent endolu- minal treatment has been described and shown to be successful with a lower mortality rate.
The subclavian arteries are relatively well protected from blunt trauma. Patients may present with absent distal pulses, and injury should be suspected in patients with a first rib fracture or traction injury to the brachial plexus. In stable patients, careful clinical assess- ment of the brachial plexus and magnetic reso- nance imaging (MRI) should be performed prior to surgical exploration.
Direct repair of the vessel, patch, and pros- thetic or autologous interposition grafts are possible choices in repairing aortic and great vessel injuries. Some centers are now opting to use endovascular techniques (Ohki et al., 1997).
At present this method of treatment should be pursued only in institutions with adequate sur- gical and radiological expertise.
Abdominal Vascular Injuries
One third of patients with vascular trauma pre- sent with abdominal vascular injuries. These patients are more commonly victims of pene- trating injuries, with mortality rates averaging 50%. Deceleration and compression injuries are common blunt injuries and may cause damage to the renal or superior mesenteric arteries and
portal vein tributaries. Vessels can be injured by transection or partial transection, or have intimal defects causing thrombosis. Major vas- cular injury in the abdomen is often associated with injuries to other intraabdominal organs. Of those patients who reach the hospital, the mor- tality postsurgery remains high (50% to 70%
for aortic injury and 30% to 53% for vena caval injury).
Resuscitation is based on Advanced Trauma Life Support (ATLS) guidelines, with unstable patients being transferred promptly to the oper- ating room (Fig. 11.2). Intrathoracic injuries are associated in up to 25% of patients with gunshot wounds of the abdomen.
The assessment of stable patients with intra- abdominal pathology has been extensively dis- cussed; ultrasound and CT are the modalities of choice. Angiography in the stable patient with blunt injuries may be useful in documenting unusual injuries.
In unstable patients with significant hemor- rhage, laparotomy should be performed and the abdomen packed, and systematic evaluation of the abdomen undertaken. Large defects in the gastrointestinal tract should be temporarily controlled with soft bowel clamps to reduce contamination. If hemorrhage is not controlled, it may be necessary to cross-clamp the proximal supraceliac aorta via the lesser sac; alternatively (via the left thorax) the descending thoracic aorta may be cross-clamped. The goal is to obtain proximal and distal control of the hem- orrhaging vessels so that repair or ligation can quickly be undertaken. Hypothermia and coag- ulopathy is a serious risk; therefore, expeditious control is important. Aortic injuries can be repaired with a transverse primary repair, a
patch with autologous or prosthetic material, or interposition grafting with prosthetic material.
The use of antibiotic-soaked grafts may over- come concerns regarding the use of prosthetic material in the presence of penetrating injuries.
The decision to explore a retroperitoneal hematoma depends on the mechanism of injury and stability of the patient. For a retroperitoneal hematoma caused by blunt trauma, a conser- vative approach is advised especially when it is associated with pelvic fractures. This can be addressed by external fixation of the pelvis, angiography, and coil embolization. In contrast an expanding or pulsatile retroperitoneal hematoma requires immediate exploration.
Retrohepatic caval injuries are difficult to control and carry a high mortality. Mobilization of the liver with division of the right triangular ligament and right thoracotomy with dissection of the diaphragm may be required. Bleeding from the porta hepatis can be controlled by compression of the hepatic artery and portal vein (Pringle’s maneuver).
The mortality rate for patients with significant superior mesenteric artery (SMA) injury can be high (58% mortality rate). Injuries to the proximal SMA are technically challenging due to the proximity of the pancreas and the presence of multiple short branches. Control of the supramesocolic vessels can be obtained by medial visceral rotation via the left paracolic gutter. Injuries to the celiac artery and branches may present with an expanding hematoma dis- placing the stomach and pancreas forward.
Celiac axis vessels may be ligated if there is a patent SMA. Retropancreatic SMA control may have to be obtained by transection of the pancreas.
Resuscitation as per ATLS guidelines
Haemodynamically Haemodynamically
Unstable Stable
Theatre Ultrasound CT Angiography
Figure 11.2. Algorithm for the management of a patient with abdominal trauma.
Injury or transection of the SMA may require either autologous or prosthetic bypass. Bowel viability may be difficult to assess intraopera- tively; therefore, second-look laparotomy in these patients is advisable.
Inframesocolic vessel injuries can be ap- proached by mobilizing the small intestines and transverse colon superiorly. The inferior mesen- teric artery can be ligated in most patients, as collaterals exist that provide adequate blood to the intestine.
Access to the inferior vena cava, right renal vein, suprarenal aorta, and porta may be gained by an extended mobilization of the duodenum, head of pancreas, and right colon (Kocher maneuver). The infrarenal aorta is exposed by retracting the small bowel to the right and incis- ing the retroperitoneum from the root of the mesocolon to the pelvis. Simple stab wounds to the aorta may be closed primarily; more exten- sive injuries may require a prosthetic patch or bypass graft. In the presence of significant con- tamination, an axillobifemoral bypass may be preferred after ligation of the aorta. Iliac vessel injuries can be approached via the retroperi- toneum; such injuries carry a high mortality (10% to 40%) and morbidity including limb loss.
Renal artery injury may occur after rapid deceleration, resulting in acute renal artery thrombosis or laceration. The diagnosis of thrombosis is often made late, and if explored 12 hours after the injury, renal salvage is often limited. In patients with a functioning kidney on the opposite side, a “watch and wait” policy can be adopted.
The control of venous hemorrhage can be difficult. Simple injuries to the inferior vena cava can be repaired primarily with intermittent digital pressure. In severe hemorrhage, ligation of the infrarenal vena cava may be necessary; in contrast, injury to the suprarenal vena cava requires reconstruction.
Extremity Vascular Injuries
Experience both with trauma patients and with noninvasive techniques are paramount in the management of extremity vascular trauma. A low threshold for angiography should be main- tained to diagnose ischemia.
In those patients requiring surgical inter- vention, vessels are repaired by primary repair, interposition grafting, or bypass with vein (from the uninjured limb) or prosthetic mate- rial; 31% of patients with arterial trauma have concomitant venous injuries. Repair of venous injuries has been found to improve the outcome of patients with combined arterial and venous injuries (Martin et al., 1994; Pappas et al., 1997).
Grossly contaminated wounds and massive soft tissue and bone injuries require a multi- disciplinary team approach to management.
Orthopedic injuries should be reduced with external fixators, and arterial and venous shunts can be used to minimize the ischemia time. Soft tissue coverage either by extraanatomical by- pass or muscle flaps may be necessary to protect vascular repairs.
Debridement of devitalized tissue is impor- tant for postoperative wound care. Fasciotomies are also of great importance in those patients with extremity injuries who have suffered delayed repair, extensive tissue injury, swelling, elevated compartment pressures, and prolonged hypotension. The development of compartment syndrome can lead to myoglobinuria, renal failure, and skeletal muscle necrosis.
Controversies arise in the presence of exten- sive tissue damage, vascular injuries, and con- comitant nerve injuries. Unfortunate patients may be facing the future with a viable limb that is nonfunctioning and painful after multiple operations. These patients may be best served with a primary amputation. This is a difficult decision to make, and therefore should be made only after extensive discussion with the patient and family, and after the expertise of the com- bined team has been sought.
Injuries of the subclavian and axillary vessels rarely cause upper extremity ischemia due to the rich collateral network at the shoulder.
Penetrating and blunt injuries can both lead to brachial plexus injuries. Brachial artery injuries below the level of the profunda brachii may not present with ischemia due to the col- lateral supply around the elbow. Isolated injury to the ulnar or radial arteries may be treated with ligation in the presence of a complete pal- mar arch.
Injuries to the femoral vessels occur in 70%
of all arterial injuries, with penetrating trauma
being the most common etiology. In 20% to 35%
of cases in which the popliteal artery is injured, the popliteal vein and tibial nerve are also involved. Blunt injuries to the knees leading to posterior dislocation can result in popliteal artery injury in 30% to 40% of patients. Single tibial vessel injury can generally be dealt with by ligation; however, if more than one vessel is involved, repair is advocated.
Iatrogenic Vascular Injuries
With an increasing use of percutaneous tech- niques, there is also a higher risk of iatrogenic vascular injuries. In a survey of 10,500 cases following femoral artery puncture, the in- cidence of complications was 0.44% (Dorfman and Cronan, 1991). For cardiac catheterization the incidence was 0.55%, whereas peripheral angiography resulted in a complication rate of 0.17%.
The most important risk is bleeding, which may be controlled with direct pressure after a catheter has been removed. Occasionally, surgi- cal repair is undertaken to repair the punctured vessel; direct repair is adequate in most instances. Retroperitoneal bleeding is generally self-limiting; however, when the patient has been taking anticoagulants blood or pharmaco- logical products may be required to correct clot- ting abnormalities.
Pseudoaneurysms can also complicate punc- tures in 0.5% to 5.5% of diagnostic femoral punctures. Most of these pseudoaneurysms thrombose spontaneously. Many false aneur- ysms respond well to ultrasound-guided com- pression, which has now been superseded by compression with concomitant injection of procoagulant products. Surgical intervention must be undertaken acutely in the presence of a femoral neuropathy, hemodynamic instabil- ity, overlying skin necrosis, and extremity ischemia.
Arteriovenous fistulas usually present late and complicate up to 2% of cardiac catheteriza- tions. Although most of these fistulas throm- bose, a small percentage can lead to congestive heart failure or limb ischemia requiring either radiological or surgical intervention.
Vascular injury secondary to intraarterial injection of drugs can lead to extensive soft
tissue infection, mycotic aneurysm formation, and gangrene.
Endovascular Treatments
With the emergence and development of endo- vascular techniques, arterial trauma is being treated at some centers with coil embolization, intravascular stent grafts, and covered stent grafts. The use of endovascular techniques has minimized the need for extensive operative dis- sections and anesthesia; this is especially impor- tant in injuries involving vessels difficult to assess. Endovascular techniques are best uti- lized in institutions equipped and ready to handle trauma in this fashion.
Conclusion
Improvements in patient transport to a level- one trauma center combined with prehospital care have allowed patients to present earlier for treatment. The multidisciplinary team approach to the management of these patients has led to better outcomes.
In vascular reconstructive surgery autologous bypasses should be used wherever possible (vein being harvested from the uninjured limb).
In the event of this not being possible, the newer antibiotic-soaked prosthetic grafts is advocated.
Interventional radiology with deployment of endoluminal stents will continue to develop its role in vascular trauma. It is important that vas- cular surgeons remain involved in all aspects of vascular trauma to facilitate improvements.
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