Bilaterally Occurring Popliteal Artery Health Essay
Bilaterally Occurring Popliteal Artery Health Essay
Chronic Exertional Compartment Syndrome ( CECS ) is characterized by increased intracompartment force per unit areas as a map of exercising and most commonly occurs in the lower leg. During strenuous exercising, arterial influx additions to the musculuss doing them to swell.13 A normal fascial compartment can suit for this addition in muscular volume. However, in the instance of CECS, increased thickness in the fascia consequences in reduced conformity and abnormally elevated tissue pressure.2, 16 Fascial inspissating consequences in reduced ability of the compartment to suit the inflow of blood flow doing an addition in intracompartment force per unit area. Venous escape is so inhibited as the popliteal vena collapses under the force per unit area of the environing tissue ; which is referred to as Popliteal Venous Entrapment Syndrome ( PVES ) .2, 10 Entrapment of the popliteal arteria as it passes through an abnormally developed soleal musculus sling is likely due to hypertrophy of the lower leg musculuss.Bilaterally Occurring Popliteal Artery Health Essay. This categorization of encroachment is typically seen in the athletic population and is termed Functional Popliteal Entrapment Syndrome ( PAES ) .7
Although uncommon, vascular pathologies should non be overlooked when naming and handling CECS.14 In the event of a misdiagnosed vascular abnormalcy, the patient is at an increased hazard for potentially life endangering conditions such as deep vena thrombi, aneurisms, or arteriosclerosis.1 Therefore, a thorough history and proper appraisal are indispensable to positive patient results.
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Case Report
An 18 twelvemonth old female cross state and in-between distance path and field athlete reported to the Athletic Training Room complaining of bilateral shin hurting. The jock reported relentless bilateral lower leg hurting over the anterior and sidelong constructions that worsened with activity. She reported sing similar symptoms as an jock in high school and had antecedently been diagnosed with median tibial emphasis syndrome. To corroborate this diagnosing, bilateral radiogram were ordered in the anteroposterior, sidelong, and oblique positions. All consequences were negative for lytic or blastic osteal lesions – the jock had been misdiagnosed and her intervention mismanaged since high school. As the season progressed and the strength of exercises increased, the jock ‘s symptoms worsened. Initially, ice-cups, cold vortex, and electrical stimulation were used to diminish esthesiss of hurting. The end was to let her to finish a normal exercise hurting free. As the strength of developing continually increased so did the jock ‘s hurting. Alterations were made to her exercising plan and the initial modes to handle hurting through centripetal stimulation continued to supply no alleviation. She reported a painful force per unit area that began at the mortise joint and advanced toward the articulatio genus. Upon tactual exploration, her musculuss felt really steadfast but still fictile, and she reported numbness over the anterior lower leg and sidelong and median malleoli. Homan ‘s Sign was negative for thrombosis and percussion and compaction trials were negative for indicants of breaks. Symptoms were diminished with inactive plantar flexure and inversion at the mortise joint and were wholly relieved with remainder. The jock was referred to the squad doctor, and as CECS was suspected, intracompartment force per unit areas of all 8 compartments of the lower leg were tested pre and post-exercise utilizing the Stryker quick stick method ( see table 1 below ) . Elevations were noted pre and post-exercise bilaterally in the anterior compartments every bit good as post-exercise in the left sidelong compartment consistent with chronic exertional compartment syndrome. Following initial diagnosings of CECS, the jock was restricted from engagement in all exertional exercising as lasting structural harm could happen from drawn-out exposure to elevated intracompartment force per unit areas. The jock participated in aquatic rehabilitation three times per hebdomad to keep cardiovascular wellness. Full return to engagement will non be allowed until she is wholly pain free with exertional exercising and intracompartment force per unit areas remain below 15 mmHg pre-exercise and 30 mmHg 1 infinitesimal post-exercise in all compartments. Bilaterally Occurring Popliteal Artery Health Essay.
pre-exercise
post-exercise
Right Anterior
17
45
Right Lateral
14
25
Right Deep Posterior
10
12
Right Superficial Posterior
15
16
Left Anterior
17
54
Left Lateral
14
30
Left Deep Posterior
12
13
Left Superficial Posterior
14
21
Table 1. Intracompartment force per unit areas of the lower leg measured pre and post-exercise via the Stryker quick stick method.
Although typically overlooked, compartment syndrome and vascular pathologies normally coexist.11 Ankle brachial indices showed unnatural lessenings in systolic blood force per unit areas of the dorsal pedalis arterias post exercising proposing occlusion with activity ( see table 2 and fig. 1 below ) . Without farther diagnostic surveies the extent, location, and nature of the entrapment are educated speculation. The jock is scheduled to see a vascular specializer for audience.
Remainder
1
2
3
4
5
6
R Ankle ( DP )
143
125
137
112
135
131
125
L Ankle ( DP )
135
125
134
130
130
131
136
R Brachial
117
120
112
115
116
113
106
R ABI
1.22
1.04
1.22
0.97
1.16
1.16
1.18
L ABI
1.15
1.04
1.20
1.13
1.12
1.16
1.28
Table 2. Systolic blood force per unit areas recorded at remainder and at one minute intervals following 5 proceedingss of exercising over the brachial and dorsal pedalis arterias.
Figure 1. Graphic representation of systolic blood force per unit areas recorded at remainder and at one minute intervals following 5 proceedingss of exercising. ( DP = dorsal pedalis arteria )
Based on elevated intracompartment force per unit areas and unnatural mortise joint brachial indices, the jock was diagnosed with Chronic Exertional Compartment Syndrome with intuition of Popliteal Artery and Venous Entrapment Syndrome.Bilaterally Occurring Popliteal Artery Health Essay. Isolated venous entrapment without arterial engagement is a rare happening, and arterial entrapment entirely would non account for elevated intracompartment pressures.8 Common derived function diagnosings for exertional leg hurting include emphasis breaks or median tibial emphasis syndrome, every bit good as a assortment of vascular pathologies ( see table 3 below ) . Teasing out the underlying cause of leg hurting is indispensable for successful intervention. It is of import to observe that many of these conditions are non reciprocally sole and can, and often do, coexist. 2, 4
DIFFERENTIAL DIAGNOSIS
Vascular
Musculoskeletal
Condition
endofibrosis
median tibial emphasis syndrome
arterial aneurism
emphasis breaks
coronary artery disease
periostitis
adventitial cystic disease
fascial defects
emboli
nervus entrapment syndrome
deep vena thrombosis
radiculopathy
stricture of iliac arteria
gastrocnemius/soleus strain
Table 3. Differential diagnosing for Chronic Exertional Compartment Syndrome and Popliteal Entrapment Syndrome.
This jock reported to the athletic preparation room towards the terminal of preseason developing complaining of bilateral shin hurting that worsened with intense exercising. Intracompartment force per unit areas were measured in each of the lower leg compartments and important values were recorded bilaterally in the anterior compartments pre and post-exercise every bit good as the left sidelong compartment post-exercise ( see table 1 on pg. 2 ) . Peripheral vascular surveies besides showed reduced systolic blood force per unit areas bilaterally in the dorsal pedalis arterias ( see table 2 on pg. 3 ) . The inside informations of her lameness remains ill-defined until farther diagnostic testing can be performed.
Discussion
Exertional lower leg hurting has a broad array of beginnings. Typically happening together, Popliteal Artery and Venous Entrapment Syndrome and Chronic Exertional Compartment Syndrome are some of the lesser known perpetrators and are responsible for some of the more ruinous results.
Due to high rates of misdiagnoses, the incidence of Chronic Exertional Compartment Syndrome is unknown. Frequently, it is mistaken for conditions such as median tibial emphasis syndrome or emphasis breaks ( see table 3 above ) .2 Until late, the merely recognized method for naming CECS involved an invasive technique for mensurating intracompartment tissue pressure.17 With the jock positioned supine or prone on the tabular array – depending on the compartment being tested – a syringe or slit catheter is inserted into the compartment and tissue force per unit areas are recorded pre and post-exercise. However, protocol does non order the place of the mortise joint and articulatio genus during the process. Bilaterally Occurring Popliteal Artery Health Essay. 15 Drastic additions in intracompartment force per unit area ( see table 5 on pg. 5 ) are noted in the anterior and deep buttocks compartments with place 3 and 5 ( see table 4 on pg. 5 ) compared with the resting place – described as knee extension and relaxed plantarflexion.3 Unfortunately, this may take to error in diagnosing and designation of involved compartments. Magnetic Resonance Imaging ( MRI ) utilizing T2-weighted scans has been investigated as a non-invasive option to the traditional tissue force per unit area measurings. This technique measures alterations in the T2-weighted signal strength before and after exercising to find intracompartment force per unit area lifts. The usage of MRI T2-weighted scans as a diagnostic tool may turn out to be an priceless replacing of the traditional invasive method for the diagnosing of CECS.17
Resting
articulatio genus extension with relaxed plantar flexure
Position 1
10A° articulatio genus flexure, ankle impersonal
Position 2
90A° articulatio genus flexure, full inactive plantar flexure
Position 3
90A° articulatio genus flexure, full passive dorsiflexion
Position 4
full articulatio genus extension, full inactive plantar flexure
Position 5
full articulatio genus extension, full passive dorsiflexion
Table 4. Description of articulatio genus and ankle place for intracompartmental force per unit area proving for CECS.
Position
Compartment
Remainder
1
2
3
4
5
Anterior
12
12
14
16
12
17
Deep buttocks
5
8
8
16
4
23
Lateral
8
9
11
12
8
11
Table 5. Intracompartmental tissue force per unit area lifts noted with alterations in mortise joint and knee place.
Popliteal Artery and Popliteal Venous Entrapment, like CECS, is normally misdiagnosed or overlooked. Occlusion may ensue from injury but is more normally the merchandise of embryonic abnormalcies in the development of the popliteal vascular constructions or the gastrocnemius muscle.7 Initial diagnosing for PAES is made via peripheral vascular surveies utilizing Ankle Brachial Indices. Unfortunately, this widely accepted diagnostic tool gives an intolerably high false positive rate ( 72 % ) for PAES.4 Likewise, engagement of venous constructions may do false lift in mensural pressures.6 There are six categorizations of popliteal entrapment syndromes ( see table 6 on pg. 6 ) .1
4, 5 Most normally, entrapment occurs as the consequence of an accoutrement hempen set of the gastrocnemius musculus environing the popliteal arteria as seen in type III PAES.11 Type V entrapment, as suspected with this jock, histories for less than 10 % of entrapment cases.4 Recently, functional entrapment has been found to be more common among jocks than those arising from developmental abnormalities.5 Magnetic Resonance Angiography ( MRA ) is considered the gilded criterion ” for naming PAES and placing divergence of the popliteal arteria and musculus anatomy.14 Without this diagnostic tool, it is impossible to find the specific beginning of occlusion. Bilaterally Occurring Popliteal Artery Health Essay.
Type I
Medial caput of gastrocnemius is normal, popliteal arteria is deviated medially and has an deviant class
Type II
Medial caput of gastrocnemius is located laterally, no deviated of popliteal arteria
Type Three
Abnormal musculus package from median caput of gastrocnemius environing the popliteal arteria
Type Four
popliteal arteria is located profoundly and entrapped by the popliteus musculus or a hempen set
Type V
popliteal vena is besides entrapped with any type of popliteal arteria entrapment
Functional
popliteal arteria is entrapped during activity without structural abnormalcies
Table 6. Categorizations of Popliteal Entrapment Syndrome
Aggressive intervention is recommended for CECS and PES ( PES or Popliteal Entrapment Syndrome refers to arterial and venous entrapment as seen in type V entrapment ) . Surgical intervention of CECS consists of release of the lower leg compartments via fasciotomy. For successful results, attention must be taken to guarantee all involved compartments are to the full and decently released. Decompression of the anterior compartment has shown to hold high success rates ( 96 % ) while less than satisfactory results have been attributed to inadequate release of involved compartments.2 Surgical intercession for PAES operates under the same basic rule ; the end is to let go of the arterial compaction and return the anatomy to its normal place, leting unobstructed arterial flow to the diagnostic limb.7 Delayed intervention may ensue in irreversible arterial harm and the viability of the limb can be impaired.12 Specific surgical attacks are at the discretion of the sawbones and vary harmonizing to the categorization of entrapment. Harmonizing to criterion processs, a posterior attack with an S-or-Z molded scratch is used ; nevertheless, more critical instances may justify a median attack. If arterial harm is important, a saphenous vena transplant may be used as a replacement.7 If functional entrapment is suspected, a median attack is recommended with division of the muscular part of the median caput of the gastrocnemius while continuing the sinew. A saphenous vena transplant may besides be warranted in this procedure.4 Patients who require surgical release entirely and make non undergo vascular Reconstruction study better long term patency rates.6
Chronic Exertional Compartment Syndrome and Popliteal Entrapment Syndrome are normally coexisting pathologies but are non normally diagnosed together. CECS is characterized by increased intracompartment force per unit area with strenuous exercising that consequences in terrible hurting that is merely relieved with remainder. Popliteal Entrapment Syndrome is characterized by occlusion of the popliteal arteria or vena due to unnatural anatomical development or functional damage. Mistakes and inadequacies in the diagnostic processs for these conditions is the primary cause of misdiagnoses. Bilaterally Occurring Popliteal Artery Health Essay. With greater consciousness and instruction, clinicians may break utilize the proper diagnostic tools to measure a patient with exertional leg hurting and find the implicit in cause. If CECS or PES is suspected, it is imperative intervention is non delayed.
The popliteal artery is located behind the knee in the popliteal fossa and is a direct extension of the superficial femoral artery after it passes through the adductor hiatus, an opening in the tendinous slip of the great adductor muscle of the thigh. The popliteal artery lies posterior to the femur and anterior to the popliteal vein. The popliteal artery and vein are normally located between the two heads of the gastrocnemius muscle (,,,Fig 1). Abnormalities in this relationship can produce popliteal artery entrapment syndrome (PAES). In the region of the knee, the popliteal artery gives off genicular and sural branches, eventually dividing into the anterior tibial artery and the tibioperoneal trunk. The tibioperoneal trunk further subdivides into the posterior tibial and peroneal arteries. The proximity of the popliteal artery to the distal femur makes it susceptible to injury when the distal femur is fractured or the knee is dislocated. Bilaterally Occurring Popliteal Artery Health Essay.
Clinical signs and symptoms of diseases that affect the popliteal artery overlap, but the affected patient populations are often distinct. Understanding this fact can aid the radiologist in directing imaging for diagnosis and treatment. In this article, we discuss and illustrate the clinical manifestations, imaging appearances, differential diagnosis, and treatment options in a variety of diseases that affect the popliteal artery, including atherosclerosis, aneurysm, traumatic injury, arterial embolus, PAES, and cystic adventitial disease (CAD).
Atherosclerosis
Atherosclerosis is the leading cause of morbidity and mortality in the United States and is the most common cause of popliteal artery occlusion or stenosis. The pathogenesis of atherosclerosis is well established. Endothelial injury initiates a process whereby overproduction of cellular mediators eventually produces fibrotic plaque. This plaque may calcify, fracture, ulcerate, hemorrhage, and ultimately limit blood flow or cause thrombosis of the vessel. Risk factors for atherosclerosis include smoking, diabetes, advancing age, hyperlipidemia, hypertension, male gender, and a family history of the disease.
Patients can present with a variety of symptoms depending on the degree of disease (,Table 1). Single-level disease commonly manifests as intermittent claudication. Multilevel disease will manifest with more severe ischemic symptoms of rest pain and tissue loss. At physical examination, the patient will have a decreased or absent pulse at or below levels of significant disease. Bruits may be auscultated at levels of significant stenosis.
Noninvasive arterial studies include color duplex ultrasonography (US) and an ABI with segmental lower-extremity arterial pressure readings or pulse volume recordings. These studies are cost effective and can help localize and determine the severity of lower-extremity arterial disease. MR angiography can provide noninvasive, arteriographic localization of disease, but at a greater cost. Gadolinium-enhanced three-dimensional time-of-flight MR angiography can provide diagnostic accuracy similar to that of standard contrast material–enhanced angiography. High-quality imaging requires a certain level of expertise and is best performed with a stepping table (,2) or sequential imaging with multiple injections (,3). Bilaterally Occurring Popliteal Artery Health Essay. There are still problems with variable runoff times and image degradation at the trifurcation due to venous filling. Conventional angiography is usually performed when endovascular or surgical intervention is required.
Atherosclerosis will appear at angiography as irregularity in the vessel lumen in the form of stenosis or occlusion (,Fig 2). When atherosclerosis is the cause of popliteal artery stenosis or occlusion, similar vessel irregularity is found at other locations in the peripheral runoff. Over time, with popliteal artery occlusion or significant stenosis, collateral vessels will reconstitute distal runoff. Commonly, branches of the deep femoral artery will provide collateral vessels for the more distal popliteal or trifurcation vessels via sural or genicular branches.
Interventional therapy for lower-extremity atherosclerotic disease commonly involves percutaneous transluminal angioplasty (PTA), thrombolytic infusion, and, less often, stent placement. Pentecost et al (,4), in conjunction with the American Heart Association task force, designed a classification scheme for popliteal and superficial femoral artery disease to help decide whether treatment should consist of PTA or surgery (,Table 2). Since that time, the SCVIR (Society of Cardiovascular and Interventional Radiology) Transluminal Arterial Revascularization (STAR) registry (,5) analyzed 219 limbs in which PTA of the femoropopliteal artery had been performed. In the STAR registry, category 1 lesions had patency rates of 87% at 36 months, and category 2 and 3 lesions had a patency rate of 69% and 67%, respectively. These patency rates are similar to those achieved with bypass surgery (,,,Fig 3).
Thrombolytic therapy can be used to treat acute and subacute occlusions of the popliteal artery due to underlying stenosis. Thrombolytic therapy is most successful if initiated within 2 weeks after thrombosis (,6). Therapy is initiated with a catheter with multiple side holes that is positioned across the occluded segment. Constant infusion of a lytic agent is usually required for 8–36 hours with intermittent follow-up angiography. Stenoses are often uncovered, which can then be treated with PTA.
Primary stent placement in the popliteal and superficial femoral arteries is not indicated because the long-term patency rates are poor (,7). Stent placement in the popliteal artery should be reserved for cases of failed PTA. Self-expanding stents should be used because of the superficial location of the popliteal artery and concerns about extrinsic compression. Surgical therapies generally consist of bypass grafting (,,,Fig 4) and, less often, endarterectomy and patch angioplasty. When the popliteal artery is bypassed below the knee joint, a vein graft is superior to a synthetic graft. Bilaterally Occurring Popliteal Artery Health Essay.
Popliteal Artery Aneurysms
Generally, aneurysms can be categorized as either true or false. True aneurysms occur when all layers of the arterial wall are abnormally dilated. False aneurysms (pseudoaneurysms) are due to a defect in the arterial wall related to trauma or (mycotic) infection. Trauma may be related to iatrogenic injury due to surgery or intervention.
The popliteal artery is considered aneurysmal if its diameter exceeds 0.7 cm. Aneurysms may rarely be associated with connective tissue diseases such as Marfan syndrome or Ehlers-Danlos syndrome or, even more rarely, with pregnancy. Almost all true aneurysms are nonspecific. Historically, the nonspecific form of aneurysmal disease that affects the abdominal aorta and the iliac, femoral, and popliteal arteries has been described as “atherosclerotic.” Risk factors associated with atherosclerotic disease are also associated with nonspecific aneurysms. However, atherosclerotic disease and these risk factors incompletely define the cause of these aneurysms, which appears to be multifactorial.
True aneurysms of the popliteal artery are the most common peripheral arterial aneurysms. Popliteal artery aneurysms (PAAs) are relatively uncommon compared with abdominal aortic aneurysms (AAAs), but recent studies have identified an increase in the prevalence of PAAs that may be due to greater access to imaging modalities such as US. Consequently, reports vary as to the ratio of PAAs to AAAs, which ranges from 1:8 to 1:23 (,8,,9). PAAs are associated with aneurysms in other locations. An AAA is present in 30%–50% of patients with a PAA. In contrast, PAAs are present in only about 10%–14% of patients with AAAs (,9,,10). PAAs are bilateral in 50%–70% of cases. These associations have important implications. In patients with a PAA, it is important to look for AAAs and a contralateral PAA. Bilaterally Occurring Popliteal Artery Health Essay. PAAs are usually found during the 6th and 7th decades of life and have a strong male predilection, with a male:female ratio ranging from 10:1 to 30:1 in published reports (,10–,12).
It is very important to diagnose PAAs because of the risk of limb-threatening thrombotic complications. About 45% of patients with PAAs are asymptomatic at the time of diagnosis. Symptomatic patients present with lower-extremity ischemia, which can manifest as claudication, rest pain, or severe ischemia associated with thrombosis or embolization (,,,Fig 5). In general, US is the most commonly used and the best imaging modality for diagnosing PAAs. US can help determine the presence and patency of an aneurysm and whether the aneurysm contains thrombus. Color Doppler US also helps distinguish an aneurysm from a popliteal mass such as a Baker cyst (,,,,Fig 6). Conventional angiography may not help identify PAA, especially if the artery is occluded. MR imaging may be helpful in that it will delineate the aneurysmal sac and mural thrombus.
PAAs can be complicated by thrombosis, distal embolization of thrombotic material, and, rarely, rupture. Studies have shown that complications occur in 18%–31% of such aneurysms that were not corrected surgically (,13). Thrombolytic therapy is often required in patients who present with acute thrombosis to recanalize the distal popliteal and trifurcation vessels as targets for bypass surgery (,,,,,Fig 7). Despite the thrombus burden present within popliteal aneurysms, thrombolytic therapy is very successful in patients who can withstand an additional period of ischemia (,14).
It is currently recommended that asymptomatic PAAs be repaired unless surgery would put the patient at high risk. This recommendation is based on the high prevalence of complications regardless of the size of the aneurysm, the high amputation rate after complications develop, and the lower graft patency rate in patients who have experienced complications (,9).
Trauma
The popliteal artery is susceptible to injury due to its proximity to the distal femur and knee joint. Anterior and posterior knee dislocations as well as fractures are often associated with popliteal artery injury. Popliteal artery occlusion is seen in 30%–50% of patients with complete knee dislocation (,15). In today’s society, such injuries are most commonly caused by motor vehicle accidents, but injury related to penetrating trauma is not uncommon. These traumatic injuries include laceration, dissection, occlusion, and posttraumatic pseudoaneurysm formation (,,,,,Fig 8). Trauma affecting the popliteal artery and vein will occasionally produce an arteriovenous fistula (,Fig 9).
Diagnosis of popliteal artery trauma requires a high degree of suspicion on the part of the clinician. Any traumatic injury to the knee should prompt a thorough arterial examination of the affected extremity. Bilaterally Occurring Popliteal Artery Health Essay. A knee can be dislocated and subsequently relocated prior to presentation. Furthermore, the clinical findings can be misleading: The presence of distal pulses does not rule out injury to the popliteal artery, nor does normal distal capillary refill (,16–,18). Ultimately, a patient with knee dislocation may require arteriography to rule out injury to the popliteal artery. The angiographic appearance may vary from intimal dissection to complete occlusion of the artery (,Fig 10).
Patients with severe trauma and obvious arterial injury at clinical examination will usually proceed to surgery. Surgical treatment involves bypass grafting or patch angioplasty. Percutaneous treatment currently plays no role in management. Again, timely diagnosis and treatment is critical to decrease morbidity and obviate limb amputation (,16).
Arterial Embolus
The popliteal artery, like any other peripheral artery, can be affected by embolism. Macroemboli have a tendency to lodge in the popliteal artery at the bifurcation into the tibioperoneal trunk and anterior tibial artery. An embolus in the lower extremities most often has a cardiac source. Other sources include aortic aneurysms and proximal arterial plaque or ulceration. Regardless of the source, acute arterial embolism almost always requires urgent treatment.
Patients with arterial embolism present with acute symptoms. The five cardinal signs and symptoms of arterial ischemia are pain, pallor, pulselessness, paresthesia, and paralysis. With an occluding embolus, the patient will experience acute rest pain. The lower leg and foot will appear pale and have no pulses. If the condition is left untreated, it can progress to paresthesia and paralysis. Noninvasive arterial examination may be performed prior to angiography. With acute occlusion, there may be a total lack of Doppler signals at the ankle; thus, an ABI cannot be obtained. Color duplex US can also be used to depict thrombus, but the patient will usually proceed to angiography due to the acute clinical presentation. Thrombus in the popliteal artery appears as a complete angiographic occlusion producing the classic “meniscus sign,” a filling defect or abrupt vessel cutoff (,,,,,Fig 11). Bilaterally Occurring Popliteal Artery Health Essay.
Options for treatment of acute embolism include systemic anticoagulation therapy, percutaneous thrombolytic therapy, surgical embolectomy, and mechanical thrombectomy. The degree of ischemia that the patient is experiencing will often dictate therapy. If the ischemia has progressed but is possibly reversible, surgical options might be more timely, considering the time it takes to perform thrombolysis. Thrombolytic therapy has proved to be effective, with minimal risk of hemorrhagic complications, and reduces the need for surgical procedures with similar limb salvage rates (,6,,19,,20). Other interventional techniques involve mechanical thrombectomy devices that decimate or suction the thrombus (,21,,22). Treatment should be initiated within hours of the onset of symptoms for the best prognosis.
Popliteal Artery Entrapment Syndrome
The abnormal relationship of the popliteal artery to the gastrocnemius muscle was first described by a medical student, T. P. Anderson Stuart, in 1879 (,23). It wasn’t until the 1960s that the term popliteal artery entrapment syndrome, or PAES, was first used (,24). PAES is a developmental abnormality that results from an abnormal relationship of the popliteal artery to the gastrocnemius muscle or, rarely, an anomalous fibrous band or the popliteus muscle. The abnormal position causes deviation and compression of the artery. There are essentially four anatomic variants of PAES (,Fig 12). Type V is any of the four anatomic variants that includes the popliteal vein (,25).
Recently, a “functional” PAES has been described in patients with normal anatomy (type VI [,Fig 12]). In such cases, compression of the popliteal artery may be due to an anatomically normal but hypertrophic muscle. This entity is usually seen in well-conditioned athletes.
The true prevalence of PAES is unknown. Patients are typically young (60% <30 years old), healthy males (15:1 male predilection) (,25). Bilaterally Occurring Popliteal Artery Health Essay. Early reports cited a prevalence of 0.165% in young males entering military service (,26), and a postmortem study found PAES in 3.5% of cases (,27). PAES may be more common than previously recognized. In young athletes with calf claudication, 60% of cases may be due to PAES (,28). Bilateral popliteal artery involvement has been reported in 22%–67% of presenting patients (,29). Turnipseed (,30) found that patients with functional PAES are younger than those with the anatomic types (mean age, 24 vs 43 years) and are more commonly female (60% vs 28% of cases). Patients with PAES usually present with calf claudication and, rarely, with ischemia due to thrombosis. At physical examination, these patients may have normal pulses that disappear or decrease with plantar flexion or dorsiflexion of the foot. In patients with PAES, resting ABIs will usually be normal, but ankle pressures will decrease with exercise. Duplex US may demonstrate stenosis at color imaging and increased velocities with the flexion maneuvers. MR imaging and MR angiography are valuable noninvasive studies because of their capacity to demonstrate the vessel lumen as well as the surrounding anatomy to help determine if the artery-muscle relationship is normal. Stress angiography (ie, angiography performed in the neutral position as well as with the foot in either dorsiflexion or plantar flexion to elicit the compression) is usually performed to confirm the diagnosis prior to surgery. Imaging commonly shows a normal arterial lumen with the foot in the relaxed position, with narrowing of the arterial lumen during stress maneuvers (,,,Fig 13).
If left untreated, PAES almost invariably progresses to permanent narrowing of the popliteal artery due to repeated microtrauma to the vessel, with subsequent fibrosis making the vessel susceptible to thrombosis (,28). Surgical release of the muscle or tendon is the ultimate treatment in PAES types I–V (,28). Interventional thrombolysis would be appropriate therapy for patients who present with occlusion due to PAES. Thrombolysis of the distal popliteal and runoff vessels can be very important prior to surgical correction. The affected segment of the popliteal artery is usually bypassed or replaced once thrombosis has developed due to fibrosis. There are no indications for angioplasty or stent placement in patients with PAES. In patients with functional PAES, myomectomy of the medial head of the gastrocnemius muscle can result in complete relief of symptoms but is recommended for patients with “discrete and typical symptoms” because narrowing of the popliteal artery with plantar flexion or dorsiflexion may occur in up to 50% of the general population (,31). Bilaterally Occurring Popliteal Artery Health Essay.
Cystic Adventitial Disease
CAD occurs when mucoid cysts in the adventitia compress the popliteal artery. This entity was first described in 1947 by Atkins and Key (,32) in a patient with CAD that affected the external iliac artery. Since then, there have been many case reports, usually involving young men with intermittent claudication in whom surgery revealed a mucoid cyst of the popliteal artery. A review by Jasinski et al (,33) established that CAD occurs where large arteries are associated with joints. The popliteal artery is the most common location (85% of cases), but other investigators have reported involvement of the external iliac, common femoral, radial, and ulnar arteries. The cause of this disease is not completely known. Levien and Benn (,34) discuss the four theories concerning the causes of CAD and the authors who have indicated support for each theory. These theories include (a) a myxomatous systemic degenerative condition associated with a systemic disease, (b) repeated trauma, (c) cysts arising from synovial ganglia that migrate into the adventitia, and (d) mucinous cysts arising from mucin-producing mesenchymal cell rests incorporated into the vessel wall during development (the theory favored by Levien and Benn).
CAD is rare, accounting for only 0.1% of vascular disease. Patients are usually men in their mid-40s who present with intermittent claudication. Claudication can have an acute onset but rarely manifests as rest pain. At physical examination, there is decrease or loss of pulses and, rarely, a popliteal bruit. The ABI will be decreased, and the segmental pressures or pulse volume recordings will indicate a pressure drop across the affected popliteal artery. Duplex US will depict an arterial stenosis with surrounding cysts, which contain no flow. These cysts appear as anechoic or hypoechoic masses in the wall of the vessel. The cysts can manifest as distinctive stenoses of the vessel lumen at angiography.Bilaterally Occurring Popliteal Artery Health Essay. If the cysts are concentric, the stenosis will have an “hourglass” appearance; if they are eccentric, the stenosis will demonstrate the classic “scimitar sign.” Although conventional angiography has traditionally been the study of choice, it has recently been suggested that MR imaging is equal in diagnostic capability. MR imaging provides the most information (,35). Cysts are hyperintense on T2-weighted MR images and have variable signal intensity on T1-weighted images because of the variable amount of mucoid material within the cysts. Compression of the popliteal artery produced by cysts can be seen on axial MR images (,,,,,,Fig 14) and angiographically with three-dimensional time-of-flight imaging.
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Because CAD is a rare condition, treatment methods are derived anecdotally. Cyst aspiration has been described (,36), but cysts may recur. Balloon angioplasty (,37) does not appear to be beneficial because it will not affect the cystic compression of the artery. Surgical evacuation of the cysts with maintenance of the native artery appears to be the preferred treatment. Occasionally, the artery cannot be preserved and a vein graft is required. Although not reported, in the rare case in which thrombosis of the popliteal artery has occurred, thrombolytic therapy would be appropriate prior to surgical correction, which would likely include bypass surgery.
Conclusions
The popliteal artery can be affected by a variety of pathologic conditions, the most common of which is atherosclerosis. Affected patients are usually older, presenting with other risk factors for atherosclerosis, less acute symptoms, and disease at multiple levels. PAA and embolus also manifest in these patients, but symptoms will be more acute with occlusion of the popliteal artery. When aneurysm of the aorta or of the iliac, femoral, or popliteal artery is diagnosed in one location, appropriate imaging should be performed to find associated aneurysms. In younger patients and in those without generalized atherosclerosis, the differential diagnosis includes trauma, CAD, and PAES. A high degree of suspicion may be necessary to make these relatively rare diagnoses. Color duplex US with segmental arterial pressure readings or an ABI can help localize and determine the extent of popliteal artery disease. MR imaging and MR angiography are important imaging tools, especially in CAD and PAES. Angiography is usually performed prior to surgical treatment and in conjunction with interventional therapies such as angioplasty and thrombolytic therapy. Bilaterally Occurring Popliteal Artery Health Essay.
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Bilaterally Occurring Popliteal Artery Health Essay
