Carotid artery injury constitutes 5% to 11% of all arterial injuries and is most often the result of high-velocity penetrating trauma and stab wounds, therapeutic or diagnostic catheterizations in the neck, craniocervical fractures, or blunt trauma to the neck. The incidence of carotid AVFs from penetrating trauma ranges from 4% to 27%. The communication is usually between the carotid artery and the internal jugular vein or its tributaries.^{7,10,11,18,19,21,22}

Subclavian and Axillary Arteries

Approximately 3% of all neck and chest trauma is associated with injuries to the subclavian artery or vein.²³ The subclavian vein is involved in 44% of cases and the artery in 39%; in the remaining 17% of patients, both vessels are injured. As previously noted, most of these vascular injuries are due to penetrating injuries; fractures of the clavicle and first rib rarely cause vascular injury.^23,24 In a series of 57 subclavian injuries reported by du Toit et al, 23% resulted in AVFs.²⁶ In contrast, AVFs are less commonly associated with penetrating axillary artery injuries than with subclavian trauma, with only one AVF identified in a review of 85 penetrating axillary artery injuries.²⁷

Central venous catheterization and therapeutic catheter manipulations to treat dialysis access–related complications may also be complicated by subclavian and axillary AVFs. Inadvertent puncture of the subclavian or carotid arteries occurs with sufficient frequency (up to 8.4%) that one should consider the possibility of this complication if a pulsatile mass or bruit becomes evident at the site of catheterization in these areas.^18,19 It is estimated that the incidence of AVF following subclavian vein catheterization is 0.58%.²⁵

Vertebral Artery

Vertebral artery AVFs are characterized by a communication between the vertebral artery and the internal jugular and/or vertebral veins. The incidence of vertebral artery injury due to penetrating trauma ranges from 0.7% to 7.4%, depending on the mechanism of injury (gunshot versus stab wound) and the indications for angiography, which demonstrates these injuries.^8,28 Blunt trauma from cervical spine fractures, chiropractic manipulation, or closed head injury accounts for a small number of cases.²⁸ The vertebral artery can also be injured during operative procedures on the cervical spine and catheterization of the jugular vein. In a series of vertebral AVFs reported by Vinchon et al, 56% were the result of trauma; of these, 64% (18 of 28) were due to iatrogenic injury.^28,29

Brachial and Forearm Arteries

Upper extremity vascular injuries accounted for 25% of all vascular injuries in a report by Clouse et al⁷ Brachial and forearm arteries were involved in 22% of cases and were transected in 23% of cases reported by Fox et al, with no mention of AVFs involving these vessels.⁶ In a series of civilian AVFs due to stab wounds, 22% of which were in the upper extremity, 12% of patients had AVFs involving forearm vessels.¹⁰ Other potential causes of AVFs in these locations include diagnostic and therapeutic cardiac and vascular catheter manipulations to treat coronary, visceral, and subclavian stenotic lesions and the placement of percutaneous intravenous central catheters.^30–32

Femoral Artery

The common femoral artery is the preferred access site in about 85% to 90% of percutaneous cardiovascular interventions and is also the most common site of iatrogenic AVFs. In addition to the common femoral artery, the superficial femoral artery and profunda femoris artery are frequently involved. The incidence of iatrogenic AVFs diagnosed by physical examination ranges from 0.006% to 0.86% following cardiac catheterization, and femoral AVFs are slightly more frequent after interventional rather than diagnostic procedures. A higher incidence of AVFs (2.8%) has been reported when duplex scanning is used to evaluate patients after cardiac procedures.^12,13 The factors predisposing to iatrogenic femoral AVFs are listed in Box 86-1.

Penetrating injuries due to GSWs, stab wounds, or fragment injuries from improvised explosive devices or fractures of the long bones can also lead to femoral AVFs.^6,7,12,13,33 The incidence of AVFs as a result of such injuries varies considerably between the military and civilian populations. In a review of 558 AVFs and pseudoaneurysms due to military injuries reported by Rich et al, 28% (74 of 262) of the AVFs involved the superficial femoral or profunda femoris arteries,¹¹ whereas in a civilian series of AVFs predominantly due to stab wounds, the femoral artery was involved in 12% of cases.¹⁰ Sporadic cases have also been reported of spontaneous AVFs involving the superficial femoral artery and vein.⁷⁵ With increased use of endovascular techniques for venous interventions, AVFs following endovenous ablation for varicose veins have also been reported.¹⁴⁰

Popliteal Artery

Popliteal AVFs have a similar etiology to femoral AVFs. The number of iatrogenic popliteal AVFs can be expected to increase, owing to use of the popliteal vein for the diagnosis and endovascular treatment of deep venous thrombosis. Blunt trauma associated with comminuted femur and proximal tibia fractures and orthopedic procedures on the knee may also be complicated by AVFs.^35,36 Vascular injuries associated with total knee arthroplasty and arthroscopic procedures on the knee occur in approximately 0.08% of patients undergoing these procedures.³⁶ AVFs of the popliteal artery account for approximately 16% of AVFs reported in the Vietnam registry and 5% to 14% of civilian AVFs.^10,11,34

Tibial and Peroneal Arteries

AVFs of tibial and peroneal arteries are a recognized complication of comminuted leg fractures or fragment injuries of the lower extremity and of balloon catheter thrombectomy of these vessels.^37,38 Approximately 24% of the AVFs reported in the Vietnam registry involved the tibial and peroneal arteries and largely resulted from fragment wounds.¹¹ The use of technically complicated techniques and aggressive interventional approaches can lead to higher risk of AVFs in these arterial beds.^14–17

Aortoiliac

Penetrating trauma due to GSWs, fragments, or stab wounds accounts for 10% to 20% of aortocaval fistulae (see Fig. 86-1). Less commonly, iatrogenic injury during arterial and cardiac catheterization or lumbar disk surgery and, rarely, blunt trauma have been implicated as causative factors in aortic AVFs.^39–42 An additional cause is spontaneous AVF. Rupture or erosion of an abdominal aortic aneurysm (AAA) into the IVC accounts for 80% to 90% of patients with spontaneously acquired AVF. The incidence of spontaneously acquired AVF ranges from 0.2% to 1.3% of patients with AAAs and 3% to 4% of those with ruptured aneurysms.^66–70

Iliac AVFs are uncommon (0.4% to 1.4% of AVFs) and are usually the result of penetrating trauma or lumbar disk surgery.^10,11,43 In the case of lumbar disk surgery, the integrity of the anterior longitudinal ligament is the major barrier between the disk and the aorta, vena cava, and iliac vessels. Anatomic anomalies in these locations may contribute to the occurrence of vascular injuries during orthopedic procedures. Studies have shown that the aortic bifurcation is at the center of the L4-L5 disk space in approximately 18% of patients.⁶⁵ The left common iliac artery and vein are the most common sites of injury with L4-L5 diskectomy, injury to the artery occurring in 77% of cases and injury to the vein occurring in 31% of cases.⁶² However, injuries to the right common iliac artery, IVC, aorta, and iliac veins have all been reported. Although acute arterial or venous bleeding from the operative site is the usual presentation of vessel injury during lumbar disk procedures, there have been a number of case reports of acute AVFs following lumbar diskectomy.^63,64

Renal

Renal AVFs occur most commonly after renal biopsies. Factors predisposing to biopsy-related renal AVFs include use of a large-bore needle, lack of radiologic guidance when performing the biopsy, medullary penetration, and the presence of atherosclerotic vessels.^44,45 Other causes of renal AVFs include placement of percutaneous nephrostomy tubes for ureteric obstruction, laser lithotripsy, and mass ligation of the renal pedicle.^44–47 Renal artery aneurysms may also erode into the renal vein or one of its tributaries resulting in renal AVFs.^70,71 Renal AVFs are discussed further in Chapter 148.

The incidence of biopsy-associated AVF depends on the timing of the investigative testing. Prospective angiographic studies performed immediately after biopsy have demonstrated an AVF incidence of 9% to 11%; this increased to 12% to 18% if angiography was performed 1 to 6 months after biopsy. When angiography was performed between 6 weeks and 4 years after the initial diagnosis of an AVF, 33% to 90% of the AVFs had resolved spontaneously. This is not entirely unexpected because the communication between the vein and artery in patients with procedure-related renal AVFs is usually small.⁴⁴ Isolated renal AVFs due to blunt and penetrating trauma are uncommon.

Injuries involving the splanchnic arteries and the portal vein or its tributaries can result in visceral and arterioportal AVFs. These communications may involve the splenic, hepatic, and superior and inferior mesenteric arteries or their branches^48–61 and may communicate directly with the portal vein, with its tributaries, or with tributaries of the inferior vena cava. Tomczak et al reported that 37% of arterioportal AVFs resulted from penetrating trauma and 27% from interventional procedures, with the remainder from congenital and other causes.⁴⁸

Splenic AVFs may be due to blunt or penetrating intra-abdominal trauma, mass ligation of the splenic pedicle, iatrogenic injury during splenoportography, and in rare instances, erosion of a pancreatic pseudocyst into the splenic vessels.^49–53 Rupture of splenic artery aneurysms into an adjacent major vein is sometimes the first manifestation of these lesions.⁵⁷ In fact, 44% of splenic AVFs are due to rupture of a pre­existing aneurysm into the splenic vein or one of its tributaries, especially in patients with noncalcified aneurysms.⁵¹ Hepatic AVFs are usually the result of vehicular or penetrating trauma but may occur after percutaneous needle biopsy and transhepatic diagnostic catheterizations or biliary drainage procedures.^53–59 Hepatic AVFs occur in 5.4% of patients after percutaneous needle biopsy evaluated with celiac angiography and may be either intrahepatic or extrahepatic.^53–59 Hepatic aneurysms and carcinomas are also known to erode into an adjacent artery or vein, resulting in an AVF.^55,73,74 AVFs of the superior mesenteric artery are rare and are usually the result of penetrating trauma or iatrogenic injuries to the artery or its branches.⁶⁰ AVFs may also occur after mass ligation of the vascular pedicle during gastric and small and large bowel resection.⁶¹

Neck and Upper Extremity

A rapidly expanding hematoma, carotid bruit or thrill, and dilated neck veins suggest the diagnosis of a carotid-jugular AVF. Ischemic neurologic symptoms directly attributable to the carotid AVF may result from embolization or shunting of blood through the fistula.^9,22 The clinical diagnosis of vertebral AVFs is often unsuspected; only half of patients present with overt signs and symptoms of vertebral artery injury, and ischemic neurologic symptoms are rare. Subclavian, axillary, and brachial AVFs may manifest with diminished or absent peripheral pulses, abnormal forearm blood pressure measurements, arm swelling, dilated veins, hand ischemic symptoms, and a pulsatile mass with a thrill and bruit. Radial and ulnar AVFs are usually asymptomatic and manifest as a thrill or bruit over a small pulsatile mass.

Aortoiliac

Abdominal or back pain is the presenting symptom in 70% to 80% of patients with spontaneous AVFs involving the aorta and iliac arteries. A pulsatile mass or pronounced aortic pulsation is usually present. In 75% of cases, there is a holosystolic murmur, but a thrill may be palpable in only about 25% of patients. Symptoms of CHF, including fatigue, shortness of breath with exertion, anorexia, nausea, leg swelling, oliguria, hematuria, and rectal bleeding due to rupture of mucosal veins in the bladder and rectum, may be present in 11.5% to 35% of cases. Patients with traumatic AVFs are usually young, healthy males with a history of trauma weeks, months, or years previously.^50,67–70

Renal and Splanchnic

Patients with spontaneous aortorenal fistulae may present with abdominal pain, hypertension, hematuria, varicocele, non–contrast-enhancing “silent” left kidney, CHF, and rarely, renal insufficiency.^70,72 Small renal AVFs are usually discovered incidentally, with a bruit over the kidney the only evidence of their presence. Blood flow through larger renal AVFs is estimated to approach 60% to 82% of the total ipsilateral renal blood flow.⁴⁵ With such high flow rates through the fistula, a significant portion of the kidney perfused by the involved artery may become ischemic, leading to hypertension.

The presentation of patients with symptomatic splanchnic AVFs includes abdominal pain, mesenteric ischemia, gastrointestinal hemorrhage, and symptoms and signs of portal hypertension. Patients who develop AVFs associated with lumbar disk surgery usually manifest symptoms within days or weeks after the procedure, and the clinical presentation may range from a lower abdominal holosystolic murmur with a small, occult fistula to massive leg swelling, signs of CHF, and an abdominal bruit with a large fistula.

Lower Extremity

An expanding hematoma, bruit or thrill, and newly developed lower extremity edema following trauma or interventional procedures suggest the presence of lower extremity AVFs. Most iatrogenic AVFs are small and will seal spontaneously. Certain risk factors, such as large communications, connections at branch points, and anticoagulation, may prevent closure of these procedure-related AVFs. Long-standing AVFs can lead to lower extremity arterial insufficiency due to a “steal” phenomenon. However, more frequent findings include low extremity venous insufficiency secondary to venous hypertension, high-output cardiac failure resulting from increased venous return, or aneurysmal degeneration of the artery. Table 86-1 summarizes the specific vascular injuries and associated incidence and presentation of common peripheral AVFs.