In most individuals, the brachial artery divides to form the radial and ulnar arteries just distal to the elbow. These two arteries are joined distally by an extensive collateral network involving the superficial and deep palmar arches. This means that in more than 90% of people, the radial artery can be sacrificed without compromising the blood supply to the hand; therefore, radial artery cannulation and radial artery harvest are usually safe. The Allen test was originally described by Dr. Allen in 1929 and in this first description it was used in the diagnosis of ulnar artery occlusion secondary to thromboangiitis obliterans. The test was performed by occluding the radial artery at the wrist after emptying the hand vasculature by clenching the fist for 1 minute.1,2 The test is now widely used to assess independent vascular integrity of the radial and ulnar arteries to the hand as well as their interconnection via the palmar arches. Ideally, the hand should remain well perfused when either the radial or ulnar vessels are occluded providing the palmar arches are intact. The Allen test may be described as abnormal in cases where there is ulnar artery occlusion. It is better to describe it as abnormal rather than “positive,” as it can be confusing to remember what “positive” or “negative” can mean in such tests. The Allen test is a simple procedure yielding consistent results, and its ability to predict perfusion of the hand following radial artery harvesting has been demonstrated.2–4 It can be a useful part of the upper limb vascular assessment particularly where there may be signs of decreased perfusion or where the radial or ulnar arteries may be required for harvest. A normal Allen test does not exclude exercise-induced ischemia to the limb, as it assesses only perfusion at rest. It may be that there is a partial occlusion/compression of the distal ulnar artery by a mass or fascial band for example, which allows sufficient flow at rest but not during exertion. A full physical exam of the upper limb should include assessment of the appearance of the hand and fingers including skin color, temperature, turgor, nails, and capillary refill. It should also include a full assessment of motor and sensory nerve function as well as assessment of distal pulses, any obvious masses, and bruits. Any abnormal findings can direct the examiner to consider more specific tests. The Allen test does not provide information regarding the motor or sensory nerve function, nor whether any imaging has been performed.
Conventional angiography remains the gold standard for assessing the upper extremity vasculature in most settings. It is an invasive test that requires arterial access (typically in the groin or contralateral radial artery) and catheter placement in the desired location. It remains the best study to determine stenosis and occlusion in small distal vessels, particularly in patients with calcified vessels when artifact may prevent accurate examination by other modalities. A particular strength of this modality is that endovascular intervention can be undertaken at the same time as diagnostic angiogram. Unfortunately, angiography does expose the patient to ionizing radiation and IV contrast dye as well as the possibility of access complications (e.g., hematoma, arteriovenous [AV] fistula formation).1 CTA/computed tomographic venography is another common modality for assessing the upper extremity vasculature, particularly in the setting of trauma. It is quick with high-quality images and may be used in patients in whom magnetic resonance imaging (MRI) is contraindicated. Disadvantages include exposure to ionizing radiation and contrast dye (which can induce contrast nephropathy and acute kidney injury). Usually, iodine-based contrast agents used in CT are responsible for this effect.2 In contrast, magnetic resonance angiography (MRA/MRV) does not expose the patient to ionizing radiation and the contrast material (gadolinium) used is less nephrotoxic than the iodine-based materials used in CT. However, MRA is more expensive, time consuming, and does not allow for endovascular intervention. While gadolinium is far less nephrotoxic than iodine-based contrast, it is not risk free. For example, it may carry a risk of deposition in the brain, which as yet has no proven specific morbidity, but may do so in the future.3 Ultrasound has a major role in the assessment of upper limb vasculature, especially in vascular malformations. It is pain free, noninvasive, nonionizing, and low cost. Traditionally, it has been limited by the availability of a suitably trained sonographer or radiologist, but with recent advances in technology and equipment availability many surgeons have the potential to develop sonography skills to use in their everyday clinical practice.1
Emboli to the upper extremity are relatively uncommon representing less than 20% of all embolic events. However, when they do occur, it is a surgical emergency that requires multifaceted management. The five Ps associated with acute arterial obstruction are: Pain, pallor, pulselessness, paresthesia, poikilothermia) as evident in this case. The standard treatment for acute arterial obstruction is immediate IV heparin therapy in combination with an embolectomy using a Fogarty catheter. This procedure is generally performed by the vascular team. Subsequent anticoagulation treatment with either warfarin or low-molecular-weight heparin is required to prevent recurrence. Other newer alternative medical therapies such as apixaban or rivaroxaban may be considered instead of warfarin. Intra-arterial thrombolysis of the distal upper extremity is not standard practice but has been shown to be effective in select cases. When this is performed, both a thrombolytic agent such as urokinase and a calcium channel blocker are used to achieve simultaneous vasodilation and thrombolysis. Management of emboli secondary to penetrating trauma such as catheter-related brachial artery occlusions is managed differently because many patients will continue to have compromised circulation even once the thrombosis is removed. In these cases, it may be necessary to perform open repair of the involved artery with primary resection and repair, or an interposition vein graft. Long-term anticoagulation is not necessarily required in such cases.1–3
4. Komeda M, Buxton BF, Raman J, Mullaly L, Hare DL. Allen test — new value of the “old” test. J Am Coll Cardiol 1998;31(Ab- stract):425
Aneurysms are classified as either true or false according to the layers of the arterial wall involved. True aneurysms involve all three layers of the arterial wall (intima, media, and adventitia) where false aneurysms do not. Instead, they represent a collection of blood leaking out of a vessel that is confined by the surrounding tissue. False aneurysms are far more common in the upper limb and typically result from arterial perforation such as arterial cannulation or blood gas sampling (i.e., iatrogenic injury). Blood leaks into surrounding tissue and the hematoma later resolves and is replaced with scar. There is no single specific clinical finding with a suspected aneurysm, although frequently a pulsatile painful mass is felt at the site. Other potential signs include cold intolerance, altered sensation, distal embolism, and thrombosis causing critical limb ischemia. Radiologic imaging can help differentiate between true and false aneurysms, which are fusiform or saccular in shape, respectively. There are limited data to guide management of upper extremity aneurysms, but a treatment plan must be individualized to the symptoms of the patient and may include observation only, surgical excision and ligation, or surgical excision and revascularization.1,2
This patient has sustained a common childhood fracture that can be associated with damage to the brachial artery either during the initial injury or during fracture reduction. Loss of arterial flow can occur due to direct compression of the artery within the fracture site or secondary to arterial thrombosis following intimal damage. A persistent abnormality after fracture reduction requires urgent investigation and warrants operative exploration. Brachial artery thrombectomy with arterial repair or vein grafting should be anticipated. This would normally be undertaken with a multidisciplinary approach involving plastic, orthopaedic, and vascular surgeons. It is vital to assess neurovascular status of these children at multiple stages. While this child has a frankly ischemic limb and there is no question that this should be explored, there is perhaps unexpectedly greater controversy regarding the pink pulseless limb. Even if the limb is pink, if it remains pulseless postreduction, it is better to avoid missing a treatable arterial injury and explore the limb.1 An associated neuropathy in a pink pulseless limb, particularly of the median nerve, further increases the likelihood of the brachial artery injury being sufficient to require surgical management and should aid the decision to explore.2 Intraoperatively, the median nerve should be identified just as carefully as the brachial artery, and normal status documented, or repair undertaken, as this lies in close proximity to the artery and is also at risk of injury in a supracondylar fracture. No further imaging is required in this case, but noninvasive Doppler studies may be helpful in documenting abnormal pulses in an injured extremity, where there remains uncertainty about distal perfusion. Arteriography is best avoided in children because of the risk of iatrogenic damage. Embolectomy alone would not be recommended as the artery and median nerve need to be visualized along with the fracture site in this case. The cause of the occlusion (the fracture) must also be addressed.3,4
Raynaud’s disease and Raynaud’s phenomenon are distinctly different, although the terms are often used interchangeably. Raynaud’s disease (primary Raynaud’s) is a condition that involves reversible ischemia of peripheral tissues secondary to vasospasm. It is most commonly treated with nifedipine, a calcium channel blocker, although phosphodiesterase inhibitors such as sildenafil may be helpful too. Other medications sometimes prescribed include angiotensin-converting enzyme inhibitors, angiotensin II receptor antagonists, α-blockers, nitrates, and the selective serotonin receptor uptake inhibitor fluoxetine. Raynaud’s phenomenon (secondary Raynaud’s) refers to the same vasospasm process in association with another illness, which is most commonly autoimmune. The most common association with Raynaud’s phenomenon is scleroderma; however, it is not a given she will have this. Patients first presenting with Raynaud’s should be investigated for an autoimmune condition. In Raynaud’s disease, fingers are most commonly affected, but the nose, ears, and toes may also be involved. Raynaud’s disease can occur at any age, although commonly begins in the second or third decade and is not the typical age of first presentation in this case (i.e., age 45 years). Raynaud’s phenomenon tends to present later in adult life.1,2
Clinical examination findings are frequently normal in TOS, although certain provocative tests aim to aid identification, and so a careful history is very important. Although cervical ribs are involved in most arterial cases, they are rarely present in venous and neurologic cases. The most common site of neurologic compression is the scalene triangle (between the anterior scalene, middle scalene, and upper border of the first rib) and many patients have congenital fibromuscular bands in this region. Females are more commonly affected by TOS than males, and this difference is most apparent in neurologic TOS, with a ratio of 3.5:1. Adson’s test assesses the radial pulse during compression of the subclavian artery with positional change but is unreliable, as patients without TOS may have considerable positional pulse variation.1 Surgical decompression is usually performed using an open supraclavicular approach, or less commonly transaxillary.1
Hemangiomas are a type of vascular tumor that may arise in utero or during the first few weeks of life. They are therefore classified as either infantile or congenital, depending on the time of first presentation. They are distinctly different from vascular malformations.1 Classic infantile lesions show three phases of growth, with first appearance as a vascular papule followed by rapid growth, then involution. Traditional teaching suggests that by the age of 7, approximately 70% of infantile hemangiomas have spontaneously involuted, but not all subtypes do so. Congenital hemangiomas are mature at birth and are classified by their natural history as either rapidly involuting (RICH) or noninvoluting (NICH). Because most hemangiomas involute, surgical intervention is not usually required. Problematic hemangiomas, such as those that ulcerate or affect function, may be treated with surgery, sclerotherapy, laser therapy, or beta-blocker medication. Those that leave a fibrofatty remnant or skin excess may also benefit from surgical excision.1–3
Vascular malformations are inborn errors in embryonic development that occur between weeks 4 and 10 of intrauterine growth. The causes are not well understood and most occur spontaneously. Males and females are equally affected, and although all malformations are present at birth, they may not be clinically evident. For example, a triggering stimulus during puberty or pregnancy can precipitate the first clinical signs of the malformation.1–4
Glomus tumors are benign vascular lesions containing cells from the glomus apparatus involved in thermoregulation that commonly affect the nail bed and fingertip. They often present as a bluish discoloration under the nail plate, with or without nail ridging. Although lesions are often painful and solitary, this is not always the case and multiple painful or painless lesions may be present. Hildreth’s sign is observed in patients with glomus tumors of the hand, where pain is abolished on exsanguination of the limb with inflation of a blood pressure cuff. There is supporting evidence to show the efficacy of this test in the diagnosis of glomus tumors, with sensitivity and specificity above 90%.1 Love’s sign is elicited when point pressure is applied to the nail bed with a pinhead at the site of the tumor, resulting in intense pain. There are usually enough other signs to make a diagnosis without performing this test, which is clearly unpleasant for the patient. The skin color changes described here are more characteristic of those described by patients with Raynaud’s disease, where the hand passes through a series of vascular changes: white (pallor), blue (cyanosis), and red (hyperemia). Although most cases of glomus tumor (75%) are found in the hand, the condition is not exclusively seen in this site. They may be present in the toes or even in extracutaneous sites such as bone and the gastrointestinal tract. Following examination, further imaging with ultrasound or MRI may be useful. Treatment of upper limb glomus tumors is with surgical excision.2,3
This patient has hypothenar hammer syndrome where repetitive blunt trauma to the hypothenar area leads to a true aneurysm (not false) of the ulnar artery in the area of Guyon’s canal. This typically occurs in upholsterers, carpenters, and carpet layers. The repetitive trauma results in tunica media damage followed by aneurysm formation and then eventual arterial thrombosis (not venous). Patients present with cold intolerance, pain at night or with repetitive activity, and skin changes to the ulnar digits. If neglected, the digits can ulcerate.1,2 Patients with minimal symptoms, but normal flow through the radial artery, and a complete palmar arch can be observed, and symptoms treated medically, with acetylsalicylic acid (ASA) and a calcium channel blocker (nifedipine). However, patients with a proven aneurysm, recurrent embolic events, or persistent symptoms despite medical management require surgical intervention with resection of the affected arterial segment and, most likely, reconstruction of the damaged section of the ulnar artery with a vein graft. This procedure also allows for simultaneous decompression of the ulnar nerve in Guyon’s canal which can help alleviate nerve compression symptoms that may also be present secondary to the aneurysm. Unfortunately, repair and revascularization may fail early due to the local anatomy and background cause without lifestyle alteration, i.e., stopping the regular trauma which caused the problem in the first instance.1,2 A false aneurysm tends to occur following arterial puncture as an acute trauma and is usually iatrogenic. Most will settle spontaneously, although a minority will also require surgery to excise the damaged section and graft it. Venous thrombosis typically presents with a swollen upper limb with signs of venous congestion such as bluish skin discoloration and altered capillary refill. Glomus tumors affect the digits most usually at the level of the nail bed resulting in painful subcutaneous nodules. Raynaud’s phenomenon more typically presents with bilateral bouts of ischemia to the digits, which are self-limiting and resolve spontaneously. Neither of these conditions would present as in this scenario.
This woman has the typical features of a glomus tumor, which is a benign vascular lesion commonly affecting the fingertip, most often beneath the nail plate. The glomus apparatus contains an AV shunt that contributes to temperature regulation. The classic clinical triad observed with glomus tumors is cold hypersensitivity, paroxysmal pain, and pinpoint tenderness. Glomus tumors may be classified into three groups: solitary lesions, multiple painful lesions, or multiple painless lesions. Imaging can sometimes be useful with MRI or Doppler ultrasound prior to treatment. MRI may typically show a dark, well-defined lesion on T1-weighted images and a bright lesion on T2-weighted images.1,2 Doppler ultrasound studies can help detect the high blood flow in glomus tumors. Surgical excision of the lesion is generally the treatment of choice, either directly through sterile nail matrix or with a lateral subperiosteal approach.
Thoracic outlet syndrome refers to compression of the neurovascular structures of the upper limb as they pass between the neck/thorax and axilla. It can involve variable combinations of neurovascular signs and symptoms. The patient in this scenario is most likely to have TOS with an arterial component. This would explain the exercise- induced ischemic pain he is experiencing and the time frame over which the problems have been present. The most commonly affected structures in TOS are the brachial plexus (95%), subclavian vein (4%), and subclavian artery (1%). Most presentations are nonemergent and require only symptomatic treatment and referral. There are a number of potential anatomical compression points including the Scalene triangle (between the anterior scalene, middle scalene, and first rib), cervical ribs, and congenital fibromuscular bands of the cervical transverse processes. Arterial problems tend to be associated with the first two areas of compression. Treatment in this case will be to address the site of compression and then to address any ongoing vascular abnormalities.1,2 Buerger’s disease may present in a similar age patient but would tend to affect the lower limb. Compartment syndrome would present with acute-onset pain and swelling to the affected limb, most often after trauma. An arterial thrombosis would tend to present with a pale, cool ischemic limb, while a venous thrombosis would tend to present with a swollen congested limb.1–3
The patient in this scenario has evidence of acute-onset venous thrombosis of the upper limb, most likely the subclavian vein. This is termed effort vein thrombosis when associated with vigorous upper limb exercise in a healthy individual, as in this case, and can be caused by an underlying undiagnosed thoracic outlet compression. It is a rare condition that tends to affect young, active, and otherwise healthy people and is also known as Paget– Schröetter syndrome. It is thought to occur as a result of repetitive minor trauma to the subclavian vein where it passes between the first rib and clavicle. This type of venous thrombosis is distinctly different from other forms of deep vein thrombosis with respect to the underlying pathophysiology, clinical presentation, and functional consequences, so requires swift management of the thrombus in the acute setting followed by addressing the underlying cause. Management will therefore likely involve early catheter-based venography, thrombolytic therapy, and prompt paraclavicular thoracic outlet decompression with direct subclavian vein reconstruction.1 Buerger’s disease would tend to present in a young patient with signs of limb ischemia similar to an older patient with atherosclerotic disease. An arterial thrombosis would present with a white, cool peripheral limb and would normally be managed with embolectomy. Autoimmune vasculitis can present with numbness and coldness to the affected limb with easy fatigability and altered pulses. There will usually be other systemic clues in the history that raise suspicion of a vasculitis such vascular compromise to internal organs (bowel and kidney), jaw claudication, visual disturbances, and skin changes.2
The patient in this scenario demonstrates features of Buerger’s disease, which includes intermittent claudication of the lower limbs, poor lower limb perfusion, and sparing of the upper limbs in a young person who smokes heavily. The tar staining and lack of other medical comorbidities are strongly suggestive of this diagnosis, which is characterized by inflammatory thrombi affecting both arteries and veins. It typically presents, as in this case, with claudication and later progresses to pain at rest and tissue necrosis. The only proven treatment is complete cessation of smoking; so, support in this is the best management for the scenario given.1 Low-molecular-weight heparin and rivaroxaban are used to treat patients who have a history of venous thromboembolism or are at high risk of developing this such as with atrial fibrillation. Rivaroxaban is an alternative to coumarin (warfarin) that is taken as a daily tablet. Where patients are undergoing major surgery, it is usual to request they stop this medication for 48–72 hours to allow reversal of its anticoagulation effects. Acetylsalicylic acid (aspirin) is used as an antiplatelet agent in patients with ischemic heart or peripheral vascular disease. It is also used in the setting of hypothenar hammer syndrome alongside nifedipine, a calcium channel antagonist, which has a powerful vasodilatory effect on the peripheral vasculature. Nifedipine is also used in Raynaud’s disease for the same physiologic effects.
position. Vascular anomalies are classified as either tumors or malformations. Hemangiomas are tumours, while other benign vascular anomalies are malformations. Malformations are congenital and comprise of abnormal vessels, be it arteries, veins, capillaries, lymphatics, or a combination of these. They are therefore most commonly described as capillary, venous, lymphatic, arteriovenous, or mixed. They can also be classified according to flow rate: low flow, high flow, or mixed flow. These features can often be identified from the history and examination alone and determine aspects of their management. Most vascular malformations can be diagnosed on clinical examination alone because of their specific characteristics; however, imaging may assist in the diagnosis and can also useful in determining extent and flow rate. Lymphatic malformations vary according to whether they are microcystic or macrocystic in nature and according to their location. They may have a soft, fluctuant consistency with minimal change on gravity, or they may be characterized by cutaneous vesicles which may contain clear fluid, or be discolored brown by bleeding. Their color can also vary according to their tissue depth and whether there is any vascular (usually venous) component. Venous malformations tend to have a blue or purple appearance according to depth, location, and size, and usually deflate with elevation of the limb or expand with dependent positioning or exercise. There may be associated firm lumps palpated due to phleboliths. Capillary malformations are not usually affected by gravity or exertion and tend to have a characteristic port- wine stain red/purple appearance. They may be smooth in the early years, or become textured (cobblestoned) in later life. Arteriovenous malformations generally feel warm and have a palpable pulsatility, thrill, or bruit. The last description above represents a hemangioma. These tend to have a characteristic bright red or “strawberry” appearance at presentation, as they represent an abnormal collection of blood vessels. By the age of 10 years, these have generally involuted spontaneously and if this is incomplete, then the color therefore changes to a paler white/pink. This involution can leave a small excess of skin and fat and this may require surgical correction.1–4