Version May 2024
INTRODUCTION — Aneurysms of the upper extremities are rare disorders that can affect the arteries extending from the aortic arch to the hand. Prevalence estimates are unknown but are felt to represent about 1 percent of all aneurysmal disease.
While the diameter that defines an aneurysm varies with anatomic location, in general, an artery is considered aneurysmal when its diameter is greater than 1.5 times the normal diameter of the native vessel.
Aneurysms including true aneurysms and pseudoaneurysms involving the vessels of the upper extremity are reviewed. Aneurysmal disease at other anatomic sites is reviewed separately. (See "Clinical manifestations and diagnosis of thoracic aortic aneurysm" and "Overview of abdominal aortic aneurysm" and "Iliac artery aneurysm" and "Femoral artery aneurysm" and "Popliteal artery aneurysm".)
ANEURYSM DEFINITION AND LOCATIONS — True aneurysms involve all layers of the vessel wall, each of which is thinned but intact. False aneurysms (ie, pseudoaneurysms) form as a result of a tear in the vessel wall due to trauma and subsequent periarterial hematoma formation.
As with other locations, an artery is considered aneurysmal when there is a focal dilation with a diameter greater than 1.5 times the normal diameter of the native vessel. Thus, the diameter that defines aortic arch branch or upper extremity arterial aneurysm varies depending on the anatomic location. (See 'Specific aneurysm sites' below.)
PREVALENCE AND ETIOLOGY — Aneurysms of aortic arch branch or upper extremity arteries are rare disorders. Prevalence estimates are unknown but are felt to represent about 1 percent of all aneurysmal disease. Prevalence estimates may be hindered by the fact that most of these aneurysms are asymptomatic and the aneurysm location affects their rate of detection.
●The distal subclavian, axillary, brachial, radial, ulnar, and palmar arteries are all relatively superficial and easily palpable in most individuals.
●The proximal-to-mid subclavian and innominate (ie, brachiocephalic) arteries are located within the chest deep to the clavicle and sternum, which makes them difficult to examine directly or by using ultrasound.
The causes of aortic arch branch or upper extremity arterial aneurysms are varied in comparison with more frequently encountered aortic or other large aneurysms (eg, femoral, popliteal).
●True arterial aneurysms of vessels arising directly from the aortic arch (innominate, common carotid, and proximal subclavian arteries) are most often due to degenerative arterial diseases and may be associated with aneurysms elsewhere in the body.
●By contrast, aneurysms of the distal subclavian artery as well as axillary, brachial, radial, ulnar, and palmar/digital arteries more frequently have a traumatic etiology, which can either be from an acute injury, chronic injury from repetitive use, or iatrogenic trauma. These aneurysms are more commonly pseudoaneurysms, but true aneurysms can occur as well.
●Other etiologies for upper extremity aneurysms include a variety of connective tissue disorders, such as Ehlers-Danlos syndrome and Marfan syndrome (table 1), which can cause aneurysm formation at multiple anatomic locations, arteritis, fibromuscular disease, and infection.
●A common etiology for upper extremity aneurysm is pseudoaneurysm formation or aneurysmal degeneration of an upper extremity arteriovenous hemodialysis access.
●Another unique cause of subclavian artery aneurysm is aberrant right subclavian artery, which arises from the descending aorta and often is associated with aneurysmal degeneration at its origin in the chest (ie, Kommerell diverticulum).
CLINICAL FEATURES AND DIAGNOSIS
Clinical presentation — Most patients with upper extremity aneurysm present with a palpable, pulsatile mass, which may be symptomatic, but most are asymptomatic (70 percent in one review [1]). Upper extremity aneurysm may be detected by the patient or identified incidentally during routine physical examination. Symptomatic presentations are due to localized pain, particularly if the aneurysm has undergone rapid expansion, distal embolization causing ischemic symptoms in the fingers or hand [2], or, less commonly, thrombosis of the aneurysm with acute upper extremity ischemia. Upper extremity emboli comprise approximately 15 to 20 percent of peripheral emboli. While most are of cardiac origin, approximately 1.4 percent of peripheral emboli are atheroemboli or thromboemboli from an arterial source [3]. Kommerell diverticulum, due to its retroesophageal position in the chest, may present with difficulty swallowing, often referred to as dysphagia lusoria. Nerve compression as a presenting symptom is very rare but can occur. Similarly, symptoms of rupture (eg, severe pain, expanding hematoma) occur rarely.
In symptomatic cases with distal embolization or aneurysm thrombosis, the clinical presentation depends on the size of embolic debris and location of arterial occlusion(s). Macroemboli causing large vessel occlusion may present with acute limb ischemia or chronic exertional extremity pain distal to the site of occlusion, which depends on location of obstruction and the effectiveness of the collateral circulation (figure 1A-C). Microemboli may cause obstruction of smaller digital arteries and present with subungual splinter hemorrhages, finger pain, cyanosis, or ulcers. (See "Overview of upper extremity ischemia".)
Physical examination — On physical examination, an upper extremity aneurysm is generally easily palpable as a pulsatile mass due to the relatively superficial location. Exceptions are aneurysms arising from the aortic arch branches, or Kommerell diverticula, which are deep in the mediastinum or chest.
Diagnostic vascular imaging — The initial imaging modality used depends on the location of the suspected aneurysm, and in particular, whether the suspected aneurysm is located more superficially (distally) and therefore easily amenable to duplex ultrasound, or more deeply (proximally) situated, requiring advanced vascular imaging. (See 'Suspected aneurysm in superficial locations' below and 'Suspected aneurysm in deep locations' below.)
Of note, while digital subtraction angiography (DSA) is regarded as the gold standard for many vascular pathologies, it is generally not needed as a purely diagnostic test, as the diagnosis can almost always be made with less invasive methods (ie, duplex ultrasound, computed tomographic [CT] or magnetic resonance [MR] angiography). In addition, since only the arterial flow channel is opacified with DSA, an aneurysm with intraluminal thrombus but a normal flow channel may not be demonstrated. Often only mild luminal irregularity is seen.
However, DSA is particularly helpful in operative planning for those with indications for surgical intervention. If a patient requires a distal bypass due to thrombotic or embolic phenomena stemming from the aneurysm, DSA more clearly defines the suitability of a distal vessel as a bypass target.
Endovascular treatment is also possible in the setting of conventional arteriography, although endovascular treatment is less frequently performed for upper extremity aneurysms compared with aneurysms in other sites.
Suspected aneurysm in superficial locations — Most upper extremity aneurysms suspected in more superficial locations, such as the distal subclavian, axillary, brachial, and more distal arteries, can be confirmed with duplex ultrasound. Features reported from the ultrasound examination include aneurysm diameter, patency, and presence or absence of intraluminal thrombus.
Advance imaging techniques such as CT and MR angiography have less utility as vessel diameter decreases distal to the elbow, but these imaging modalities may still may adequately demonstrate larger aneurysms.
If detailed imaging is needed, standard DSA may be used, which provides better resolution of the vessels of the forearm and hand. The use of magnified views and intraarterial vasodilators, such as nitroglycerine and papaverine, may be needed to provide optimal views of the distal forearm and hand.
Suspected aneurysm in deep locations — For suspected proximal aneurysms arising from the aortic arch and aneurysms associated with an aberrant right subclavian artery, we suggest CT angiography as the first-line study to definitively demonstrate the aneurysm. MR angiography is more limited due to long acquisition times but may be a suitable alternative in selected patients for those who cannot undergo CT angiography (eg, those with allergies to iodinated contrast). Advanced vascular techniques are required due to the location and depth of these aneurysms. While many practitioners regard DSA as the gold standard for diagnosis of aneurysms involving the aortic arch branches, it is more expensive compared with CT or MR angiography and provides less information about surrounding soft tissue structures, and while uncommon, it carries a risk of periprocedural stroke.
Duplex ultrasound is less useful for aneurysms of the aortic arch branches.
●Ultrasound evaluation of the innominate (brachiocephalic) and mid-to-distal subclavian arteries is challenging due to their intrathoracic location and overlying bony structures (sternum, clavicle).
●Duplex ultrasound evaluation of common carotid artery aneurysms is variable. The distal common carotid artery may be amenable to ultrasound evaluation but due to its location within the thorax, the proximal common carotid is much more difficult to evaluate.
However, if aneurysm of an aortic arch branch is large or contains a significant amount of thrombus, dampened Doppler waveforms distal to the aneurysm may be identified, suggesting a more proximal abnormality. Regardless, if an aortic arch branch aneurysm is identified (including distal common carotid artery aneurysm) on ultrasound, the aneurysm should also be evaluated with CT or MR angiography.
DIFFERENTIAL DIAGNOSIS — Most focal masses (pulsatile, nonpulsatile) should be easily differentiated from a patent or thrombosed upper extremity aneurysm with duplex ultrasound or contrast-enhanced cross-sectional imaging.
●The differential diagnosis of a pulsatile upper extremity mass is relatively small. Vascular malformations, while typically congenital, may present as a vascularized upper extremity mass. (See "Venous malformations" and "Arteriovenous malformations of the extremities" and "Overview of vascular intervention and surgery for vascular anomalies".)
●For those aneurysms that present without pulsation (ie, thrombosed aneurysm), the differential diagnosis of upper extremity mass includes upper extremity tumors, both benign (eg, lipoma) and malignant (eg, sarcoma). (See "Clinical presentation, histopathology, diagnostic evaluation, and staging of soft tissue sarcoma".)
●Other potential causes of upper extremity masses include discrete fluid collections such as abscesses, seromas, hematomas, or enlarged lymph nodes. In the neck, aortic arch branch aneurysms can be mistaken for cystic hygroma, branchial cleft cyst, salivary gland tumors, and carotid body tumors.
MANAGEMENT PRINCIPLES — The management of aortic arch branch or upper extremity arterial aneurysms is based largely on observational data consisting of case reports and case series.
Indications for and type of repair — Symptomatic aortic arch branch or upper extremity arterial aneurysms require repair to alleviate symptoms and manage the sequelae of embolization. We also repair asymptomatic aortic arch branch or upper extremity arterial aneurysms that demonstrate significant intraluminal thrombus, or when aneurysm diameter is twice the diameter of the adjacent normal artery, to reduce the risk of upper extremity ischemic complications, which can lead to serious functional impairment. Smaller asymptomatic upper extremity aneurysms without evidence of intraluminal thrombus can be observed with periodic ultrasound examination to evaluate for expansion or thrombus formation.
It is reasonable to repair asymptomatic aneurysms at any diameter, particularly when intraluminal thrombus is present to prevent ischemic complications, which can lead to serious functional impairment, rather than watchful waiting. Unlike aneurysms in other locations, there are no agreed-upon size criteria for repair of aortic arch branch or upper extremity arterial aneurysms; however, a diameter twice the normal adjacent artery is an accepted, although unproven, axiom.
Symptomatic or asymptomatic aneurysms of appropriate size should be managed with open surgical repair, the manner of which depends on aneurysm location and presence and extent of distal embolization. Since upper extremity aneurysms are generally focal, direct repair with interposition grafting is typically feasible. The choice of vascular conduit depends on artery diameter and location. Distal thromboembolectomy or bypass may be needed if extensive embolization with resultant digital ischemia has occurred. In general, due to their superficial location and presence in a highly mobile area, endovascular repair is not appropriate; however, in larger, more centrally located arteries, endovascular treatment is gaining popularity.
Aneurysms associated with an aberrant right subclavian artery, known as Kommerell diverticula, require special consideration. Direct repair requires a thoracotomy for adequate exposure. However, aneurysm exclusion can often be achieved by placing a thoracic aortic stent over the arterial origin and providing a distal extra-anatomic reconstruction (eg, carotid-subclavian bypass or subclavian transposition), completing the aneurysm exclusion.
Evaluation for other aneurysms — Patients with upper extremity aneurysms that have a propensity for aneurysm formation at other arterial sites should undergo screening and surveillance imaging, as appropriate.
In general, upper extremity aneurysms do not predispose to aneurysmal degeneration at other anatomic sites; however, there are exceptions:
●Approximately 30 to 50 percent of patients with degenerative aneurysms of the innominate and subclavian arteries will develop aortoiliac or other peripheral aneurysms. (See "Epidemiology, risk factors, pathogenesis, and natural history of abdominal aortic aneurysm" and "Iliac artery aneurysm" and "Popliteal artery aneurysm".)
●Patients with aneurysms associated with connective tissue disorders (eg, Marfan syndrome, Ehlers-Danlos syndrome) can present with aneurysms at multiple locations. (See "Genetics, clinical features, and diagnosis of Marfan syndrome and related disorders" and "Clinical manifestations and diagnosis of Ehlers-Danlos syndromes".)
●Approximately 20 percent of patients with a Kommerell diverticulum have an associated abdominal aortic aneurysm. (See 'Kommerell diverticulum (aneurysm of aberrant proximal subclavian artery)' below and "Clinical features and diagnosis of abdominal aortic aneurysm".)
SPECIFIC ANEURYSM SITES
Innominate artery aneurysm
Clinical summary — Innominate artery (ie, brachiocephalic artery, brachiocephalic trunk) aneurysms are relatively rare, representing 2 to 5 percent of all arch vessel aneurysms and overall less than 1 percent of all peripheral artery aneurysms [1,4-7]. The most common cause of innominate artery aneurysms is degenerative disease or atherosclerosis, which accounts for at least 50 percent of true innominate artery aneurysms [1,4-7]. Other less frequent causes include syphilis, tuberculosis, Kawasaki disease, Takayasu arteritis, Behcet disease, and connective tissue disorders (eg, Marfan syndrome, Ehlers-Danlos syndrome). Trauma is another potential cause, with the majority of these being pseudoaneurysms [1,4-8]. Infected (mycotic) innominate aneurysms are rare but have been reported [9].
Most innominate artery aneurysms are discovered incidentally, with approximately 25 percent presenting with symptoms [1,4-6,10]. Symptoms are variable and can include:
●Pain from expansion or rupture
●Acute or chronic ischemic symptoms from thromboembolism to the:
•Brain manifesting as transient ischemic attack or stroke
•Right upper extremity manifesting as acute limb ischemia or chronic exercise-induced fatigue, rest pain, or tissue loss
●Upper extremity pain or neurologic dysfunction from brachial plexus compression
●Hoarseness from compression of the right recurrent laryngeal nerve
●Dyspnea due to tracheal compression
●Horner syndrome (miosis, ptosis, and anhidrosis) from compression of the cervical sympathetic chain.
●Hemoptysis from erosion into the apex of the lung
●Hemodynamic collapse from aneurysm rupture, which is rare but is potentially life-threatening occurring in approximately 10 percent of patients
The innominate artery is generally too deep to palpate. Occasionally a supraclavicular bruit can be auscultated. Signs of an innominate artery aneurysm detectable on physical exam may include absent or diminished distal pulses, signs of microembolization (eg, splinter hemorrhages or "blue finger" syndrome), neurologic deficits (sensory and motor) from brachial plexus compression, hoarseness secondary to vocal cord dysfunction from recurrent laryngeal nerve compression, or Horner syndrome (miosis, ptosis, and anhidrosis) from compression of the cervical sympathetic chain.
Computed tomographic (CT) angiography is the most reliable method of evaluating innominate artery aneurysms, providing information about aneurysm diameter, thrombus burden, and the relationship of the aneurysm to surrounding structures. (See 'Diagnostic vascular imaging' above.)
Classification and treatment — Any symptomatic innominate aneurysm should be repaired as should those containing thrombus, which presents a risk of thromboembolic stroke or limb-threatening ischemia. Because approximately 25 percent of patients will develop ischemic symptoms with ligation or embolization without restoration of distal perfusion, reconstruction is recommended. For asymptomatic innominate artery aneurysms, there is no definitive guideline, but repair is generally recommended for all saccular aneurysms, or fusiform aneurysms >3 cm diameter.
●Open surgical repair – Open surgical repair remains the standard for treating innominate artery aneurysm, although it is associated with significant morbidity and mortality, largely owing to the need for a median sternotomy and potentially cardiopulmonary bypass. In addition, many of these patients are older, with multiple comorbidities.
Exposure of the innominate artery is performed through a median sternotomy, sometimes with extension of the incision into the right neck, depending on the distal extent of the aneurysm. Depending on individual anatomy, either a full or a partial median sternotomy is performed [1,6-11]. In selected cases, innominate artery aneurysm can be repaired through a cervical approach [12]. (See "Surgical and endovascular techniques for aortic arch branch and upper extremity revascularization", section on 'Innominate/proximal subclavian'.)
The choice of conduit for innominate artery aneurysm repair is usually a prosthetic graft (PTFE or Dacron), which provides a better size match to the native artery compared with autogenous conduit, except in cases of mycotic aneurysm repair, in which case autogenous conduit is used preferentially.
An anatomic classification has been proposed to guide open surgical repair [10].
•Group A: Type A innominate aneurysms involve the innominate artery only, distal to its origin from the aortic arch.
•Group B: Type B aneurysms involve both the innominate and its origin from the aortic arch. This is the most common anatomic variant.
•Group C: Type C aneurysms involve the innominate and its origin, and the ascending aorta is also aneurysmal.
For type A and B innominate aneurysms, the proximal graft anastomosis is usually to the ascending aorta proximal to the origin of the innominate artery, and the innominate artery origin is oversewn or closed with a patch angioplasty, if needed. (See "Surgical and endovascular techniques for aortic arch branch and upper extremity revascularization", section on 'Aortic arch branch reconstruction'.)
For type C aneurysm, the involved aorta is also replaced with a prosthetic graft, from which the innominate artery bypass originates. This type of repair is much more complex, requiring cardiopulmonary bypass and hypothermic circulatory arrest. Distally, the bypass graft extends to normal innominate artery; for cases in which the origins of the right subclavian and common carotid arteries are involved, a bifurcated graft may be necessary. (See "Overview of open surgical repair of the thoracic aorta", section on 'Ascending aorta'.)
●Endovascular repair – Endovascular treatment is appealing, as it obviates need for a median sternotomy. The available data on stent-graft repair of innominate artery aneurysm suggest that it is feasible and effective for those who are candidates for repair, but most are case reports or limited series with short-term follow-up [1,7,13,14]. No all patients are candidates for treatment with stent-grafts, largely owing to anatomic constraints. True innominate aneurysms rarely have adequate proximal and distal seal zones, and coverage of branch vessels can be associated with complications. In addition, any stent placed in or near the thoracic outlet is at risk of compression and fracture, due to the highly mobile nature of this area. If endovascular treatment is pursued, either balloon-expandable or self-expanding covered nitinol stents can be used.
Common carotid aneurysm
Clinical summary — Common carotid artery aneurysms are very rare, representing only 0.4 to 4 percent of arch vessel aneurysms [4,5,15,16]. Within the carotid arteries, the extracranial internal carotid artery and the carotid bulb are more commonly associated with aneurysmal degeneration than the proximal common carotid artery. Extracranial internal carotid artery aneurysm is reviewed separately. (See "Extracranial carotid artery aneurysm".)
The most common cause of common carotid artery aneurysm is degenerative disease or atherosclerosis, and most patients have a history of hypertension [4,5,15,16]. Traumatic causes have also been reported, including both blunt and penetrating trauma as well as iatrogenic trauma from inadvertent arterial cannulation as a complication of attempted internal jugular central venous access [17]. (See "Blunt cerebrovascular injury: Mechanisms, screening, and diagnostic evaluation" and "Vascular complications of central venous access and their management in adults".)
Other etiologies for common carotid artery aneurysm include arteritides (eg, Takayasu arteritis, Behcet disease), connective tissue disorders (eg, Marfan syndrome, Ehlers-Danlos syndrome), fibromuscular dysplasia, radiation injury, and infection [4,5,15,16,18,19].
Carotid artery aneurysms are more likely to be symptomatic compared with other arch vessel aneurysms, with approximately 14 to 43 percent of patients presenting with symptoms [4,5,15]. Symptoms are variable, and may include:
●Pain from expansion or rupture
●Cranial nerve palsy from compression
●Dyspnea due to tracheal compression
●Neurologic deficits from intracranial thromboembolism (amaurosis fugax, transient ischemic attacks, or strokes)
●Horner syndrome (eg, miosis, ptosis, anhidrosis) due to compression of the cervical sympathetic chain
Aneurysms of the proximal common carotid artery are generally too deep to be palpated on physical exam, though aneurysms of the more distal common carotid artery can be palpated. Occasionally, a bruit can also be auscultated overlying or distal to the aneurysm. Signs of Horner syndrome (eg, miosis, ptosis, anhidrosis) may be apparent.
CT angiography is the most reliable method of evaluating suspected common carotid artery aneurysm and provides information about aneurysm diameter, thrombus burden, and the relationship of the aneurysm to surrounding soft tissue and bony structures. MR angiography is an alternative. Any common carotid artery aneurysm identified using ultrasound should also be evaluated with CT or MR angiography as well. (See 'Diagnostic vascular imaging' above.)
Treatment — The presence of common carotid artery aneurysm is an indication for repair to prevent embolic stroke. Nonoperative observation of carotid artery aneurysm is associated with unacceptable morbidity and mortality. In general, revascularization, rather than simple aneurysm ligation or excision, is recommended, since the risk of ischemic stroke without revascularization approaches 25 percent. However, in cases of rupture with uncontrolled hemorrhage or gross contamination from infection, simple ligation without reconstruction may be the best option [4,5,15,16,20].
Open surgical repair remains the standard for treatment for common carotid artery aneurysm, given the paucity of experience with endovascular repair. However, in two large metaanalyses, clinical outcomes were good regardless of treatment method used (ie, open, endovascular, hybrid) [21,22].
●Open surgical repair – Open surgical exposure of the common carotid artery is obtained by a median sternotomy. The choice of conduit for common carotid aneurysms is prosthetic material such as polytetrafluoroethylene (PTFE), which provides a better size match to the native common carotid artery compared with an autogenous venous conduit; however, for more distal common carotid artery aneurysms, or those that involve the carotid bifurcation, a vein graft bypass may be more appropriate. (See "Surgical and endovascular techniques for aortic arch branch and upper extremity revascularization", section on 'Carotid/mid-to-distal subclavian'.)
●Endovascular repair – Endovascular repair for aneurysms of the common carotid artery is appealing, as it obviates a median sternotomy. Patients must have appropriate anatomy for stent-grafting, including adequate proximal and distal seal zones. If endovascular treatment is pursued, balloon-expandable or self-expanding covered nitinol stents can be used. (See "Percutaneous carotid artery stenting" and "Transcarotid artery revascularization", section on 'TCAR for supra-aortic lesions'.)
Kommerell diverticulum (aneurysm of aberrant proximal subclavian artery)
Clinical summary — An aberrant right subclavian artery arises from the proximal descending thoracic aorta and courses from its origin to the contralateral upper extremity and is a common congenital arterial anomaly that occurs in 0.5 to 2 percent of the population (figure 2) [23-27]. A right-sided aortic arch with aberrant left subclavian artery has also been reported, but this is extremely rare, with an incidence of 0.05 percent in the general population [24] While typically considered a normal variant, prenatal diagnosis of aberrant right subclavian artery can be associated with chromosomal abnormalities, in particular trisomy 21 (Down syndrome) and 22q11 deletion (DiGeorge syndrome) [28]. (See "Vascular rings and slings".)
The course of the aberrant right subclavian artery is usually retroesophageal, but it is sometimes retrotracheal or occasionally anterior to the trachea. Aneurysmal degeneration of the origin of an aberrant subclavian, called a Kommerell diverticulum, occurs in approximately 60 percent of cases [24-27]. Most patients in whom an aneurysm is diagnosed are over the age of 50.
Patients with Kommerell diverticula are often asymptomatic, with the aneurysm identified incidentally on imaging obtained for other purposes. Symptoms occur in about 5 percent. Symptomatic patients may complain of [24-27]:
●Dysphagia from esophageal compression by the aneurysm (termed 'dysphagia lusoria')
●Cough or stridor from tracheal irritation or compression
●Chest pain due to aneurysm expansion or rupture
●Symptoms of ischemia such as exercise-induced arm fatigue
The aberrant subclavian artery is generally too deep to present as a palpable mass; however, findings related to the presence of an aneurysm may be appreciated. Vascular signs of a Kommerell diverticulum may be identified on physical exam, such as absent or diminished distal pulses or signs of microembolization (eg, splinter hemorrhages or "blue finger" syndrome).
With Kommerell diverticula, more so than with other arch vessel aneurysms, a thorough consideration of the anatomy is crucial, as these aneurysms are frequently associated with other congenital arterial abnormalities, such as a right-sided aortic arch or a duplicated arch. CT angiography is the most reliable method of evaluating Kommerell diverticulum, providing information about aneurysm diameter, thrombus burden, and relationship to surrounding structures. CT angiography also identifies associated aneurysmal disease. Approximately 20 percent of patients with a Kommerell diverticulum have an associated abdominal aortic aneurysm. MR angiography is an alternative to CT angiography. A patient in whom there is clinical suspicion of a Kommerell diverticulum on duplex ultrasound should undergo advanced vascular imaging.
Treatment — Most Kommerell diverticula warrant repair based on either symptomatology or diameter. Many patients experience symptoms given the proximity of the aneurysm to the aerodigestive tract. There is no guideline regarding the diameter for asymptomatic Kommerell diverticulum given its rarity, but a diameter threshold of >3 cm has been proposed [24-26,29,30].
A variety of techniques for repair have been described, and the approach undertaken should be determined by the anatomy of the aneurysm, the patient's fitness for surgery, and the clinical presentation. Regardless of the approach used, intervention must address the aneurysm itself as well as revascularization of the upper extremity.
●Open surgical repair – Open surgical repair is associated with potential morbidity since it requires major thoracic surgery, often with hypothermic circulatory arrest or partial left heart bypass. However, because many of these patients present at a younger age and have fewer comorbidities, periprocedural morbidity and mortality is lower than comparable innominate or proximal subclavian aneurysms from other etiologies (eg, degenerative atherosclerotic aneurysm) [23-26,31].
Open surgical repair involves resection the Kommerell diverticulum and revascularization of the aberrant subclavian artery either simultaneously or in a staged fashion.
•Kommerell diverticulum resection can be accomplished through a left thoracotomy, right thoracotomy (in cases of a right-sided aortic arch), or median sternotomy depending on the specific anatomy.
•Revascularization can be performed to the aortic arch through a sternotomy or may be extra-anatomic through a supraclavicular approach (eg, carotid-subclavian bypass or transposition). When bypass grafting is pursued, either from the aorta or carotid, the choice of conduit is usually a prosthetic graft (PTFE or Dacron), which provides a better size match to the native aortic arch branches compared with autogenous conduit.
●Hybrid repair – Hybrid repair using an aortic endograft and extra-anatomic bypass is an appealing option to reduce the morbidity associated with sternotomy or thoracotomy and aortic cross-clamping. Multiple small cohort studies and case series have demonstrated lower rates of peri-procedural complications and overall mortality compared with open repair, with at least reasonable short- and mid-term aneurysm-related outcomes. One drawback of hybrid repair is the inability to excise the aneurysm sac, so although the aneurysm is excluded and no longer pressurized, patients may still experience compressive symptoms [32-34]. Lifelong surveillance is recommended due to risk of endoleak and aneurysm sac expansion.
●Endovascular – Purely endovascular interventions are feasible using advanced endovascular techniques such as chimney or snorkel stent-grafts or newer branched thoracic endografts. Given the rarity of this diagnosis and the sophisticated endovascular skills required, reports of total endovascular repair are scarce [35].
Subclavian artery aneurysm
Clinical summary — Subclavian artery aneurysms are very rare. The most frequent causes are atherosclerotic degeneration or trauma (acute, chronic) [1,36-38]. Atherosclerotic degeneration leads to proximal (intrathoracic) subclavian artery aneurysms, while traumatic injury causes distal (extrathoracic) subclavian artery aneurysms [36]. The subclavian artery is in a relatively protected position, so it is not typically affected by direct external trauma in the absence of skeletal injury.
A frequent cause is repetitive arterial injury due to arterial thoracic outlet syndrome (aTOS) [39-43]. Such patients most often have a cervical rib causing direct trauma to the artery with arm motion, but aTOS can also occur in the absence of cervical rib from arterial impingement between the clavicle and first rib, or by the anterior and middle scalene muscles. This disorder is occasionally seen in competitive athletes such as baseball pitchers, swimmers, and rowers [44]. Patients with history of clavicular fracture, especially with any degree of malunion, are particularly susceptible. (See "Overview of thoracic outlet syndromes".)
Other causes of subclavian artery aneurysm include a variety of connective tissue disorders such as Ehlers-Danlos syndrome and Marfan syndrome, infection (ie, mycotic aneurysm), fibromuscular dysplasia, tumor, instrumentation, and vasculitis (eg, giant cell [temporal] arteritis and Takayasu arteritis, although vasculitis is typically associated with arterial stenosis rather than dilatation) [1,36,38,45,46].
Most subclavian artery aneurysms are asymptomatic, presenting as a pulsatile supraclavicular mass.
●When symptoms occur, the most common are ischemic manifestations of distal embolization.
•Macroemboli can cause acute or chronic upper extremity ischemia with upper extremity pain on exertion or at rest depending on the size, location, and duration of emboli.
•Microemboli can cause digital symptoms including subungual splinter hemorrhages or digital pain, discoloration, or ulceration.
●Rarely, subclavian artery aneurysms can cause symptoms of local nerve compression, which can present with a Horner syndrome (recurrent laryngeal nerve) [36,38].
●Arterial TOS can also occur in conjunction with neurogenic TOS (nTOS) manifesting with upper extremity motor or sensory abnormalities in the brachial plexus distribution [39,40].
Physical examination should include palpation and auscultation in the supraclavicular fossa and infraclavicular region. While sometimes obscured by the overlying clavicle, a pulsatile mass is often present on palpation, and a bruit can occasionally be heard on auscultation. Distal pulses should also be palpated, since emboli from the aneurysm can cause distal arterial occlusion. The hands should also be examined for evidence of distal emboli (subungual splinter hemorrhages, digital discoloration, or ulceration).
CT angiography is the most reliable method of evaluating subclavian artery aneurysms, demonstrating the aneurysm but also any intraluminal thrombus that may be responsible for distal embolization. MR angiography can be used as an alternative. The ability to evaluate subclavian artery aneurysms using ultrasound is variable. The overlying clavicle often obscures the subclavian artery; however, the aneurysm can still be imaged in many cases; in most cases, additional imaging is still necessary. Catheter-based digital subtraction angiography (DSA) is most useful for the evaluation of the distal runoff when distal embolization is a concern. With appropriate techniques, including hand warming, magnified views, and, if necessary, use of intra-arterial vasodilators, DSA provides the greatest detail in patients being evaluated for arterial reconstruction.
Treatment — All symptomatic subclavian artery aneurysms and asymptomatic aneurysms with intraluminal thrombus should be repaired. Small asymptomatic aneurysms without intraluminal thrombus may be managed conservatively and evaluated with serial imaging. There is no consensus on an aneurysm diameter threshold above which repair should be considered; however, two times the diameter of the adjacent normal artery is a generally accepted criteria [36].
Open surgical repair is considered the standard for the treatment of subclavian artery, but endovascular repair is gaining in popularity and applicability in both the acute and chronic setting.
●Open surgical repair – Focal aneurysms can be repaired with interposition grafting through a supraclavicular approach. Prosthetic grafts (eg, Dacron, PTFE) usually provide the best size match. Autogenous conduit (ie, saphenous or femoral vein) can also be used but must be of good size match. For patients with distal thrombosis/embolus, additional revascularization may be necessary. In acute situations, embolectomy may adequately restore distal perfusion. For subacute/chronic situations, bypass to a suitable distal target may be necessary. Since these are often longer bypasses to smaller arteries in the upper arm or forearm, autogenous vein (usually great saphenous) is the conduit of choice [47-49].
For cases of thoracic outlet syndrome, concomitant surgical thoracic outlet decompression is also performed. For those with a cervical rib, cervical rib excision alone may be all that is needed to provide adequate decompression. In the absence of cervical ribs, first rib resection with anterior/middle scalenectomy is typically performed [39-42,49]. (See "Overview of thoracic outlet syndromes", section on 'Thoracic outlet decompression'.)
●Endovascular repair – Endovascular repair typically involves placement of covered stents across the aneurysmal segment.
In the proximal subclavian artery, endovascular repair can be limited by inadequate proximal or distal sealing zones, with the proximal limitation being the aortic arch, and the distal limitation being the vertebral artery. In the mid and distal subclavian artery, stents are limited by external compression.
Stenting is generally discouraged for managing aTOS in the absence of concomitant thoracic outlet decompression. However, despite this limitation, several case reports and series have reported excellent results with endovascular repair in properly selected patients [49,50].
Axillary artery aneurysm
Clinical summary — Axillary artery aneurysms are extremely rare. Most are associated with traumatic arterial injury, either acute (eg, penetrating trauma, iatrogenic injury) [51-53] or chronic (eg, prolonged crutch use, repetitive use) vessel injury [54-56]. Other potential causes include atherosclerotic degeneration, arteritis [57], connective tissue disorders [58,59], or congenital or idiopathic etiologies [60,61].
As with subclavian artery aneurysms, most axillary artery aneurysms are asymptomatic on presentation and present with a pulsatile axillary mass. Arm symptoms can occur in the presence of distal embolization or nerve compression [54,57,62]. Rupture is rare but has been reported [63]. Palpation of the infraclavicular region or axilla allows for detection of most axillary artery aneurysms. Evaluation of the distal arm and hand should be performed to assess for signs of distal embolization.
The axillary artery is well suited to evaluation by ultrasound, and most axillary artery aneurysms are easily seen with ultrasound. CT or MR angiography may be used to confirm the diagnosis and assist with operative planning. DSA is not necessary for the diagnosis of axillary artery aneurysms but has a role in evaluating the arterial runoff distal to the aneurysm in cases where distal arterial revascularization is necessary.
Treatment — Criteria for repair of axillary artery aneurysm include symptomatic aneurysms of any diameter or asymptomatic aneurysms twice the diameter of the adjacent normal artery [51,64,65]. In most cases, open surgical repair is the recommended treatment for axillary artery aneurysms. Endovascular repair is typically not suitable for repairing axillary artery aneurysms due to the motion and possible external compression of the axillary artery. (See "Surgical and endovascular techniques for aortic arch branch and upper extremity revascularization", section on 'Axillary' and "Surgical and endovascular techniques for aortic arch branch and upper extremity revascularization", section on 'Local repair'.)
●Open repair – Repair of axillary artery aneurysm typically involves interposition grafting. One caveat in repairing axillary artery aneurysms is their close association with the brachial plexus, so great care should be taken when dissecting the aneurysm to avoid injury to adjacent nerve structures.
Either prosthetic conduit or autogenous conduit can be used depending on arterial diameter and length of repair. In general, larger arteries and shorter repairs can be performed with prosthetic conduit, whereas small arteries and longer repairs are better managed with autogenous vein grafts.
●Endovascular repair – Reports of endovascular repair are becoming more frequent, particularly in cases of focal aneurysms, palliation, or as a bridge to surgical repair in the acute setting. Covered self-expanding stents should be used in this setting to prevent crushing from external compression [65,66].
Brachial artery aneurysm
Clinical summary — Brachial artery aneurysms are extremely rare. The majority are due to trauma, with less frequent causes including connective tissue disorders, atherosclerosis, infection, and congenital or idiopathic causes [51,67-70]. Due to its frequent use for dialysis access inflow, brachial artery pseudoaneurysms can occur at the site of current or former arteriovenous hemodialysis access [71-73]. Also, due to its accessibility, the brachial artery can be injured during illicit drug injection, and pseudoaneurysms, sometimes fatal, can occur at this site [74].
As with most upper extremity aneurysms, brachial artery aneurysms typically present as a pulsatile mass. This can either be an asymptomatic mass or symptomatic depending on its diameter, rate of expansion, and impingement on adjacent structures. Symptoms can include pain, numbness, and paresthesias. Due to its location adjacent to the median nerve, sensorimotor deficits of the first, second, and third fingers can be present. Brachial artery aneurysms can also be the source of peripheral emboli causing ischemic symptoms in the forearm, hand, or fingers. Rupture is rare but can occur in cases of pseudoaneurysms, particularly those caused by illicit drug injection.
The brachial artery extends medially from the axilla to the antecubital fossa, so physical examination findings of a pulsatile mass in the medial upper arm should lead to high suspicion for brachial artery aneurysm. Physical examination should also focus on evidence of distal ischemia, including pulse examination and evaluation of the hands and fingers for signs of distal embolization, such as finger ulcers or subungual splinter hemorrhages. Signs of nerve compression should also be evaluated, particularly pain or paresthesias in the distribution of the median nerve (digits 1 to 3).
Brachial artery aneurysms should be easily evaluated with duplex ultrasound due to their superficial location. CT and MR angiography may also be useful, particularly in identifying intraluminal thrombus as well as evaluating adjacent inflow and outflow vessels. Digital subtraction angiography is useful in operative planning, in particular in cases where the distal runoff needs to be further clarified.
Treatment — Criteria for repair of brachial artery aneurysm include symptomatic aneurysms of any diameter or asymptomatic aneurysms twice the diameter of the adjacent normal artery. The majority of brachial artery aneurysms are repaired surgically [51,67-70,75]. Endovascular repair may be prone to stent fractures due to the superficial location, size, and frequent flexion of the artery.
●Open repair – Focal aneurysms may be amenable to surgical resection with primary repair. However, in most cases, an interposition bypass graft is necessary. Due to its diameter and location, autogenous conduit is preferred, but prosthetic conduit can be used if suitable autogenous conduit is not available.
●Endovascular repair – Endovascular repair with covered stent-grafts has been reported [67,76,77], particularly in cases of pseudoaneurysms at the site of dialysis access; however, the durability of these procedures compared with autogenous surgical repair/bypass has been questioned.
Radial/ulnar artery aneurysms
Clinical summary — Radial or ulnar artery aneurysms can be due to one of several etiologies:
●Hypothenar/thenar hammer syndrome – Hypothenar hammer syndrome is caused by repetitive trauma to the ulnar artery at the wrist due to compression of the artery against the hook of the hamate bone in Guyon space. This is most often seen in males with occupational history involving the use of the hand as a hammer (eg, auto mechanics, carpenters). Over time, this leads to aneurysmal degeneration with distal embolization [78-84]. Histologic analysis of resected arteries has revealed findings consistent with fibromuscular dysplasia, suggesting that patients who develop this disorder secondary to repetitive trauma may have a predisposition for it [84].
Much less frequently, patients may develop a similar disorder in the radial artery, thenar hammer syndrome, felt to be due to repetitive trauma of the radial artery against the scaphoid bone [85].
Aneurysms due to repetitive radial artery trauma in the anatomic snuffbox have also been described [86].
●Acute traumatic injury – With the increased use of radial artery access for percutaneous cardiovascular procedures, the radial artery pseudoaneurysms are being reported with increasing frequency, but with an overall low incidence of <0.1 percent of all transradial access procedures [87-89]. The risk increases with multiple access attempts, anticoagulation, larger sheath size, and inadequate postprocedural compression. Pseudoaneurysm has also been reported with the use of radial artery catheters used for hemodynamic monitoring [90]. In addition to iatrogenic trauma, acute forearm trauma has been reported as a cause of aneurysms of the radial and ulnar arteries [91,92]. Mycotic aneurysms have also been described [93].
●Other disorders – Aneurysms of the radial/ulnar arteries related to congenital abnormalities, connective tissue disorders, and arteritis are less frequent [94-99]. Even in patients with history of connective tissue disorder, the development of radial or ulnar aneurysms is often precipitated by a traumatic event [100]; however, spontaneous aneurysm formation has also been reported [101].
Hypothenar hammer syndrome often presents with digital ischemia in cases in which distal embolization has occurred. The ulnar artery typically supplies the superficial palmar arch, so the third through fifth fingers are most frequently affected, although due to variability in palmar arch anatomy, affected fingers can be variable (figure 1C). While much rarer, patients with thenar hammer syndrome, which affects the deep palmar arch, will most frequently present with ischemic symptoms involving the first and second digits. Presenting symptoms include pain, numbness, cyanosis, cold sensitivity, or digital ulcerations.
Ultrasound is typically the initial imaging modality and is highly sensitive in detecting both aneurysm formation and associated thrombosis. As with other upper extremity aneurysms, cross-sectional imaging with CT or MR angiography can also be performed. Digital subtraction angiography is important for operative planning, particularly when the distal outflow in the hand needs to be determined. In the presence of finger ischemia, digital plethysmography will often reveal dampened waveforms in the affected fingers. However, due to the distal nature of the disease and the presence of paired digital arteries, waveforms may be normal in many cases [84].
Treatment — Surgical repair is indicated for most radial and ulnar artery aneurysms due to symptoms, though asymptomatic patients also benefit [80,81,84,102-105]. The exceptions are those cases in which the aneurysm has thrombosed and distal perfusion is preserved through collaterals, in which case the aneurysm may be managed conservatively [83].
For patients with hypothenar hammer syndrome with no or minimal symptoms, conservative management is occasionally appropriate. This typically consists of avoidance of trauma, smoking cessation, and, potentially, use of vasodilators such as calcium channel blockers. Aspirin therapy is often recommended to prevent platelet aggregation in areas of luminal irregularity.
When surgery is pursued, the extent of surgery depends on clinical presentation and distal arterial anatomy. In most cases, aneurysm resection with autogenous vein reconstruction is performed. If isolated to the forearm and wrist, this can frequently be achieved with a saphenous vein graft and loupe magnification. For bypasses that extend past the wrist into the palm, microsurgical techniques may need to be used [106]. In these cases, use of the inferior epigastric artery has been described as a better size-matched conduit. Surgical results are typically excellent with good functional recovery and 84 percent graft patency at two years [84] and 75 percent at 4.5 years [82]. Aneurysm ligation and excision without reconstruction can be an option if adequate distal collateralization exists. In cases of acute ischemia, catheter-directed thrombolysis has also been described [107].
Post-catheterization pseudoaneurysms can often be managed conservatively with external compression, either manual or with the use of a pneumatic device [108]. Ultrasound-guided thrombin injection has been described [109,110]. Surgical repair of the pseudoaneurysm can be performed if less invasive treatment is not feasible or successful.
Palmar, digital artery aneurysms
Clinical summary — Aneurysms distal to the wrist are exceedingly rare. Existing literature consists only of case reports. Trauma is felt to be the most common etiology. These aneurysms can be due to acute trauma (ie, penetrating, blunt, iatrogenic) or chronic, repetitive use trauma [111-117]. Mycotic aneurysms secondary to endocarditis [118], congenital, and idiopathic causes have also been reported [119-125].
Due to their location, most aneurysms of the hand or fingers present as pulsatile masses, although thrombosed aneurysms will be firm and nonpulsatile. Masses may be either tender or nontender. Possible additional symptoms include numbness, paresthesias, hyperesthesia, and cold sensitivity. Rarely, compression of adjacent nerves can cause symptoms consistent with carpal tunnel syndrome [126]. The hand and fingers usually remain well perfused, but occasionally digital ischemia may be present. Typically, the hand is well collateralized, although circulation can vary (figure 1C), such that vascular reconstruction is not needed. Performance of an Allen Test may be helpful in determining this preoperatively.
A variety of imaging modalities have been used in case reports in the medical literature. These include duplex ultrasound, MR and CT angiography, and DSA. Angiography allows adequate visualization of the inflow and outflow vessels to help guide subsequent therapy [127,128].
Treatment — If asymptomatic, conservative management may be appropriate. In symptomatic cases, or if the presence of the mass in the finger or hand is bothersome to the patient, surgical management is pursued. Ligation and excision, excision with primary artery repair, and excision with interposition vein grafting have all been described with favorable results [111-114]. In rare cases, direct or endovascular embolization may be effective [129].
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: Aortic and other peripheral aneurysms".)
SUMMARY AND RECOMMENDATIONS
●Aneurysms of the aortic arch branch or upper extremity arteries are overall rare; any vessel can be affected. An artery is considered aneurysmal when its diameter is greater than 1.5 times the normal diameter normal diameter of the native vessel. Aortic arch branch or subclavian artery aneurysms are predominantly true aneurysms (involving all layers of the arterial wall), while more peripheral sites, which are more prone to traumatic injury, are more commonly false aneurysms (ie, pseudoaneurysms). (See 'Aneurysm definition and locations' above.)
●The etiologies of aortic arch and upper extremity arterial aneurysms are varied compared with aneurysms at other sites (eg, aorta, lower extremity). The most common factors include atherosclerotic arterial wall generation (aortic arch branches), trauma, connective tissue disease, arteritis, fibromuscular disease, infection (mycotic aneurysm), hemodialysis arteriovenous access, and congenital anomalies. (See 'Prevalence and etiology' above.)
●Most patients with upper extremity arterial aneurysm are asymptomatic and present with a palpable, pulsatile mass identified incidentally on physical examination. Upper extremity aneurysm may also be seen incidentally on radiologic studies obtained for an unrelated condition. Aortic arch branch or upper extremity arterial aneurysms have a propensity to thrombose or embolize distally, rather than to rupture. Symptomatic patients may present with pain at the site of the aneurysm from aneurysm expansion or with symptoms and signs of acute or chronic upper extremity ischemia or hand ischemia due to athero- or thromboembolism. Symptoms related to compression of surrounding structures can occur, varying with the location of the aneurysm. (See 'Clinical features and diagnosis' above and 'Specific aneurysm sites' above.)
●Aortic arch branch or upper extremity arterial aneurysm may be suspected based on physical examination findings (eg, bruit, mass, ischemia), but the diagnosis requires demonstration of a focal dilation of the vessel that is 1.5 times the diameter of the adjacent normal vessel on vascular imaging studies. (See 'Diagnostic vascular imaging' above.)
•For more superficially located (distal) upper extremity arteries, duplex ultrasound is the initial imaging modality of choice.
•For the more deeply situated aortic arch branch or proximal upper extremity arteries, computed tomographic (CT) angiography is the initial imaging modality of choice.
•For patients with indications for aneurysm repair, digital subtraction angiography (DSA) is useful for operative planning. The aneurysm will generally not be adequately demonstrated with DSA since only the flow channel, which is often normal in diameter, will be seen.
●Patients with symptomatic aortic arch branch or upper extremity arterial aneurysms require repair to alleviate symptoms and manage the sequelae of embolization. To prevent stroke, asymptomatic carotid artery aneurysms are also repaired to prevent embolic stroke, regardless of diameter. (See 'Management principles' above.)
●For patients with asymptomatic brachiocephalic (innominate), subclavian, or other upper extremity arterial aneurysm that demonstrates intraluminal thrombus or if the aneurysm diameter is twice the diameter of the adjacent normal artery, we suggest repair to reduce the risk of ischemic complications, which can lead to serious functional impairment, rather than watchful waiting (Grade 2C). Smaller asymptomatic upper extremity aneurysms without evidence of intraluminal thrombus can be observed with periodic ultrasound examination to evaluate for expansion or thrombus formation. (See 'Management principles' above.)
●For most aortic arch branch or upper extremity arterial aneurysms with indications for repair, we suggest surgical repair, rather than an endovascular approach (Grade 2C). Surgical repair involves aneurysm excision and interposition grafting, or aneurysm exclusion (ligation) and bypass, depending on the location of the aneurysm and whether thrombosis or embolization has occurred. Distal thrombectomy may also be required. Endovascular repair may be appropriate in selected situations (eg, innominate [brachiocephalic] aneurysm, Kommerell diverticulum, proximal subclavian); however, endovascular repair is generally not appropriate for more distal aneurysms due to their superficial location and the high mobility of the vessel, which increases the risk for stent compression and fracture. (See 'Indications for and type of repair' above.)
●Management of specific aneurysm sites including innominate (brachiocephalic), common carotid, subclavian, axillary, brachial, radial, ulnar, and palmar arteries are reviewed above. (See 'Specific aneurysm sites' above.)
ACKNOWLEDGMENT — The UpToDate editorial staff acknowledges Jill B Smolevitz, MD, who contributed to an earlier version of this topic review.
آیا می خواهید مدیلیب را به صفحه اصلی خود اضافه کنید؟
