Aim. Extrinsic compression of the popliteal artery and absence of surrounding anatomical abnormalities characterize the functional popliteal artery entrapment syndrome (PAES). The diagnosis is confirmed to individuals who have typical symptoms of popliteal entrapment and occlusion or important stenosis of the popliteal artery with color duplex sonography (CDS), magnetic resonance imaging (MRI) or arteriography during active plantar flexion- extension maneuvers. However, variable result findings in normal asymptomatic subjects have raised doubts as to the validity of these tests. The purpose of this study was to compare the frequency of popliteal artery compression in 2 groups of asymptomatic subjects, athletes and non-athletes.
Methods. Forty-two individuals were studied. Twenty-one subjects were indoor soccer players, and 21 were sedentary individuals. Physical activity was evaluated through questionnaires, anthropometric measurements, and cardiopulmonary exercise test. Evaluation of popliteal artery compression was performed in lower limbs with CDS, ankle-brachial index (ABI) measurements and continuous wave Doppler of the posterior tibial artery.
Results. The athletes studied fulfilled the criteria of high level of physical activity whereas sedentary subjects met the criteria of low level of activity. Popliteal artery compression was observed with CDS in 6 (14.2%) studied subjects; 2 of whom (4.7%) were athletes and 4 (9.5%) were non-athletes. This difference was not statistically significant (p=0.21). Doppler of the tibial arteries and ABI measurements gave good specificity and sensibility in the identification of popliteal artery compression.
Conclusion. The frequency of popliteal artery compression during maneuvers in normal subjects was 14.2% irrespective of whether or not they performed regular physical activities. Both Doppler and ABI showed good agreement with CDS and should be considered in screening popliteal arteries in individuals suspected of PAES.
[Int Angiol 2004;23:218-29]
Key words: Popliteal artery – Functional entrapment syndrome, diagnosis – Ultrasonography, Doppler, color.
Popliteal artery entrapment syndrome (PAES) is a congenital disease characterized by extrinsic compression of this artery caused either by a deviation of its normal anatomical course or its compression by musculotendinous structures in the popliteal fossa. Different anatomical variations occur as a result of embryological anomalies of arterial or muscle development in this area. The most frequent alterations include: medial deviation of the popliteal artery in relation to the medial head of gastrocnemius muscle, which can have its normal origin in the medial femoral condyle or be laterally inserted in the femoral metaphysis; compressions by the popliteal muscle, plantar muscle or by surrounding fibrous bands.1
In general, symptoms appear in young adults. The repetitive trauma to the popliteal artery by surrounding structures, may result in initially reversible lesions, histologically identified as adventitial fibrosis. The persistence of the pathological factor may cause a lesion of the medial layer, rupture of the external elastic lamina and finally thrombosis due to intimai layer degeneration.2 Clinically, subjects have intermittent claudication and decreased distal pulses with active plantar flexion-extension maneuvers. Early diagnosis is fundamental as it restricts surgical treatment to the removal of elements that entrap the popliteal artery, without vascular reconstruction.
Patients suspected of having PAES initially have their posterior tibial artery evaluated with continuous-wave Doppler and their ankle- brachial index (ABI) measurements taken. The presence of alterations in the curve components, classically described as amplitude reduction, audible Doppler signal reduction or pressure values reduction during provocation maneuvers, are considered important signs for the diagnosis of popliteal entrapment.3,4 PAES is confirmed by the presence of occlusion or important stenosis of the popliteal artery in symptomatic subjects during provocation maneuvers, with (CDS) and/or arteriography.5, 6 Lately, MRI has improved the chances of identifying surrounding structures involved in the entrapment.7
Even more recently, a functional type of popliteal entrapment, which also occurs in young adults, particularly in athletes,8 has been studied. Differently from the anatomical type, there are no morphological alterations of the popliteal artery or surrounding muscles. Symptoms such as plantar paresthesia may occur, probably as a consequence of intermittent trauma to the neurovascular bundle during physical activities. In these cases, popliteal artery thrombosis is a rare but possible event.
In 1985, Rignauld et al.9 first described functional PAES in an individual with symptoms of intermittent claudication and continuous- wave Doppler and arteriography findings indicating extrinsic compression of the popliteal artery during active plantar flexion- extension maneuvers. Despite the suggestive diagnosis of PAES, surprisingly, anatomical alterations were not observed during surgery. Only hypertrophy of the gastrocnemius muscles was observed. In this case, the skin was sutured without closing the muscular fascia. As there was a complete remission of the symptoms in the postoperative period, the treatment was considered successful due to a change in the anatomical relationship of the popliteal artery to the surrounding muscles. In a parallel study, these authors evaluated the posterior tibial artery of asymptomatic subjects with continuous-wave Doppler and identified 30% positive results in militaries and 50% in athletes.
Some authors 8,10,11 have suggested that in the functional type, in subjects who practice sports regularly leg muscle hypertrophy could be responsible for the compression of the popliteal neurovascular bundle during muscle contractions. Others have suggested that the slightly lateralized insertion of the medial head of the gastrocnemius (which can be potentiated by muscular hypertrophy) would be responsible for this compression.12, 13
With the improvement of screening tests and the use of CDS and MRI, asymptomatic subjects started to be evaluated in order to identify possible occurrence of extrinsic compression of the popliteal artery during provocation maneuvers and to analyze the influence of sport activities. Erdoes et al.14 identified 53% positive results in 36 evaluated subjects (20 sedentary subjects and 16 athletes). Huffman et al.15 had 88% positive results in 42 subjects (18 athletes and 24 sedentary subjects). In both studies, there were no significant differences as to the frequency of alterations between athletes and sedentary subjects.
We proposed this study because of the disagreement in the literature as to the percentage of asymptomatic subjects who have extrinsic compression of the popliteal artery during active plantar flexion-extension maneuvers and whether regular physical activity is responsible for positive results. Our purpose was to evaluate the prevalence of this compression in asymptomatic subjects and to observe the influence of regular physical activity in the increase of positive results.
Materials and methods
The Research Ethics Committee of the Medical School of Botucatu – UNESP – approved the present study. The purpose of the study was explained for the volunteers. They freely decided to take part in it and signed the Informed Consent Form.
Healthy, non-smoking subjects (21 indoor-soccer players and 21 sedentary subjects) took part in this study. The subjects’ mean age and standard deviation were 204 years. In the first phase of the study, the groups were analyzed and classified as to their level of physical activity. They were then evaluated to identify extrinsic compression of the popliteal artery.
TABLE I.-Classification after physical activity evaluations.
Initially, the subjects answered the short version of the International Physical Activity Questionnaire (IPAQ)16 and were classified according to the answers given: very or regularly active subjects, performing intense or moderate physical activity, more than 5 times a week and for at least 30 minutes; irregularly active or inactive subjects performing physical activity less than 3 times a week and for less than 30 minutes a day. Direct questioning was also used to determine present and previous physical activity.
The following anthropometric measurements were taken: height, weight, body mass index (BMI) and perimetry in both inferior limbs, at the greatest circumference of the thigh and leg. Percent of body fat was also calculated using the techniques of skin fold fat measurement and bioimpedance.
The determination of percent of body fat using the technique of skin fold fat measurements was performed according to Pollock protocol. Based on these measurements, body density was determined as follows:17
Body density= 1.112-(0.00043499X)+0.00000055 (X2)-(0.0002882Y), for X = sum of skin fold fat measurements (at the triceps, axila, chest, subscapula, suprailium, abdomen and thigh); Y = age of evaluated subject. After that, percent of body fat was determined using the formula of Siri:18 % body fat = (4.95/body density)-4.5.
Weight and bioimpedan\ce were taken with a Tanita electronic scale. Subjects were positioned barefoot on the base of the scale wearing the least amount of clothing possible. Weight and height values previously taken were included and impedance was determined. The calculated data were entered into the scale computer program and percent of body fat was obtained according to the bioimpedance technique.
In order to evaluate functional capacity, both groups performed cardiopulmonary exercise tests. The test was administered in a treadmill without ramp, according to the protocol of variable speed.19 The test consisted of warming up, workload and recovery phases. Initially the subject remained 2 minutes at rest and then warmed up for 4 minutes at 6 km/h. The test started at 7 km/h and 1 km/h was incremented at every 2 minutes. The test ended when the subject reached the VO^sub 2^max, in the presence of clinical symptoms or when maximum effort was established according to Borgs scale 20 (linear scale, in which the subject classifies his/her effort form 0 to 10). The recovery phase lasted 4 minutes with controlled speeds of 7, 5, 4 and 3 km/h. During the exercise in the treadmill, arterial pressures were taken using the method of indirect auscultation. Heart frequency was monitored with a transmitter attached to the chest by an elastic band, which continuously sent information to the computer program. A facial polyethylene mask was used to analyze inhaled and exhaled gases. At regular intervals, a vacuum bomb withdrew samples from the mask reservoir bag to measure the exhaled oxygen fractions (EO^sub 2^) and exhaled carbon dioxide fractions (ECO^sub 2^F). The variables (respiratory frequency, current volume, pulmonary ventilation, oxygen consumption, carbon dioxide, respiratory coefficient, oxygen pulse, exhaled oxygen fractions and exhaled carbon dioxide fractions) were analyzed through a computerized microprocessor that controlled the (unctions of the gas analyzer, entered the data, and made the necessary calculations to determine oxygen consumption (VO^sub 2^). VO^sub 2^max was obtained when oxygen consumption was stabilized, despite the increments of workload. This happened when VO^sub 2^ values reached a plateau or when maximum oxygen consumption at the end of the exercise was observed. Before every test, the volume (by injecting a known gas volume in the mask) and the composition of the gases (by analyzing the pattern mixture with 16% of O2 and 5% of CO2) were calibrated.
Once the physical evaluations were finished, the obtained data were compared with the values on Table I 21-23 to analyze the characteristics of athlete and non-athlete groups.24
In the second phase of the study, evaluations of positional compression of the popliteal artery (extrinsic compression during provocation maneuvers) with CDS and continuous-wave Doppler of the posterior tibial artery were made. These tests were performed at the Vascular Service of the ‘Hospital das Clinicas” at the Medical School of UNESP in Botucatu City, So Paulo State, Brazil. The examination room temperature was kept at about 22C.
Figure 1.-Alterations identified with CDS in the posterior tibial artery (arrow indicates beginning of maneuvers): altered waveforms curve with monophase curve of low amplitude (A), identified using CDS in subjects with total popliteal artery occlusion; waveforms altered with irregularities at the peak of high systolic speed (B) or at the biphase curve of reduced amplitude (C). These alterations were found using CDS in individuals with partial compression of popliteal artery.25
Continuous-wave Doppler, CDS tests and ABI measurements were performed in the resting position and during active plantar flexion- extension maneuvers which were obtained by pushing the foot against the hand of the operator with voluntary and simultaneous contraction of the femoral quadriceps.
The same investigator performed the continuous-wave Doppler tests. The subject was positioned in horizontal dorsal decubitus with extended lower limbs. The probe was placed over the posterior tibial artery at the medial retromaleolar region, using an angle of 60 degrees. Three evaluations were repeated in each subject and the final result corresponded to the presence of, at least, 2 coincidental values.
Based on these tests, the results obtained with continuous wave Doppler of the posterior tibial artery were:
– Normal Doppler (ND): without curve alterations at rest and with active plantar flexion-extension maneuvers.
– Altered Doppler (AD): identification of alterations in continuous wave Doppler findings during provocation maneuvers (Figure 1).25
ABI measurements were taken in all subjects at horizontal dorsal decubitus, at rest and during provocation maneuvers. Each measurement was taken 3 times and the obtained mean values were calculated. Pressures were determined with continuous wave Doppler, by first taking the systolic pressure of the right brachial artery, then by taking the pressure at the ankle with a probe positioned at the posterior tibial artery. The ABI was calculated by dividing the systolic mean values of the posterior tibial artery by those of the right brachial artery. Based on the results, ABI was considered altered when values inferior to 1 were obtained and normal when values equal or superior to 126 were obtained.
CDS tests were made with the patient in horizontal ventral decubitus and feet in neutral position and during active plantar flexion-extension maneuvers.
Two vascular ultrasound operators performed CDS evaluations. The tests were recorded in a videocassette and reviewed by a 3rd investigator who was not aware of the reports and of the groups. The popliteal arteries of both inferior limbs were examined with CDS, using an angle of 60 degrees. The whole extension of the popliteal artery was evaluated using B mode in longitudinal and transverse cuts. The popliteal fossa was also studied to identify surrounding anatomical anomalies. The popliteal artery was visualized by CDS with color gain to observe turbulence or interruptions in the flow signal. It was possible to observe the curve characteristics and to measure the speed through the analysis of the Doppler curve. The popliteal artery was evaluated at rest and during active plantar flexion-extension provocation maneuvers.
Figure 2.-Normal CDS: example of normal examination; popliteal artery seen at rest (1) and during dorsifiexion of the foot (2).
Figure 3.-Occlusion: example of altered examination with total occlusion of the popliteal artery due to its extrinsic compression when foot was in forced active plantar flexion-extension maneuvers.
Figure 4.-CDS: stenosis. A) Popliteal artery is normal with feet in neutral position; B) during active plantar flexion-extension maneuvers, a reduction of the popliteal artery caliber can be observed. Using Doppler spectral curve, the speed in the proximal segment of the artery was 79 cm/s and in the stenotic segment was 270 cm/s (rare of 3.4 [b/a], which corresponded to a stenosis higher than 70%).27
Popliteal artery alterations identified with CDS are shown in Figures 2-4.27
According to popliteal artery alterations identified with CDS, the results were classified as follows:
– Normal (N): differences in the popliteal artery at rest or with maneuvers were not identified.
– Occlusion (O): total obstruction of the popliteal artery during maneuvers.
– Stenosis (E): identification of important stenosis in B mode and color Doppler. Velocity ratios higher than 2.5 obtained with Doppler spectral curve, which corresponded to a stenosis higher than 70%. This ratio was calculated by dividing the area’s systolic speed by the proximal segment speed.
In order to evaluate the accuracy, sensitivity and specificity of continuous-wave Doppler findings of the posterior tibial artery and ABI, a study comparing them to CDS findings, considered in this case as gold-standard,28 was carried out.
TABLE II.-Summary of the procedures and materials used.
In the statistical analysis, size of the sample was determined using percent values obtained in the literature, with 5% significance and 90% power test. The Student t-test was used to compare the groups, considering whether the populational observations were homogenous or not for each variable. In the evaluation of the quantitative variables, Fisher’s test was used. A significance level of 5% was used.
Details of the procedures, materials, and protocols used are described in Table II.
Results
Evaluation results of the physical fitness: age, history of physical activity, anthropometry, and maximum oxygen consumption are shown in Table III.
The International Physical Activity Questionnaire (IPAQ) showed that all subjects in the athlete group were very active. In the non- athlete group, 6 or 28.6% were inactive and 15 (71.4%) were irregularly active.
According to Tables I and III, it was observed that all subjects in the athlete group fulfilled the definition criteria compatible with high levels of physical fitness, whereas all subjects in the non-athlete group fulfilled the criteria of sedentary subjects.
Tables IV-VI show the results of CDS of the popliteal artery and Doppler evaluation of the posterior tibial artery.
Alterations in CDS findings were identified in 10 inferior limbs of 6 subjects (4 bilateral). Bilateral alterations in CDS findings occurred in 2 subjects of the athlete group and in 2 subjects of non- athlete group. In both groups, occlusion in inferior dominant limb and stenosis on the other limb were observed (Table V).
TABLE III.-Mean and deviation pattern of the variables referring to the physical fitness evaluation.
TABLE IV.-Distribution of absolute and relative frequencies in the CDS, continuous-wave Doppler and ABI tests in relation to studied inferior limbs and according to groups.
At rest, all subjects obtained ABI values higher than or equal to 1. Altered ABI during provocation maneuvers range\d from 0.33 to 0.8 (mean of 0.59).
According to the results obtained and having CDS as gold- standard to identify positional popliteal compression, sensitivity, specificity and accuracy of continuous wave doppler Doppler and of ABI were studied (Tables VII, VIII).
Discussion and conclusions
Occlusion or important stenosis of the popliteal artery during active plantar flexion-extension maneuvers was accepted as a diagnostic criterion of popliteal entrapment. In the presence of anatomical anomalies of the popliteal artery or surrounding structures, resulting from congenital anomalies, classical PAES would be defined, whereas in the absence of these anomalies functional PAES would be diagnosed.1 However, the presence of positional popliteal compression in asymptomatic subjects who did not have anatornical anomalies brought uncertainties regarding the validity of the tests used to diagnose PAES. Erdoes et al.14 evaluated 36 asymptomatic subjects with CDS and observed that positional popliteal artery occlusion occurred in 53% of the them. Huffman et al.15 identified occlusion of the popliteal artery in 88% of 42 asymptomatic subjects. Subjects who performed different levels of physical activities were compared based on the hypothesis that muscle hypertrophy of inferior limbs caused by exercises could determine popliteal artery compression and a consequent increase in positive results.8-10 However, no important differences between athletes and sedentary subjects were identified in both studies.
TABLE V.-Distribution of absolute and relative frequencies in CDS, Doppler and ABI tests in relation to studied inferior limbs and according to groups.
TABLE VI.-Summary of altered results.
These authors had the initiative of studying positional popliteal compression tests in the normal population using a sophisticated methodology of imaging diagnoses, therefore improving previous studies made by Rignault et al.9 and Dany et al.29 with Doppler. However, in these studies, there was not a discerning selection of the groups regarding physical activity (PA) to appropriately classify the subjects as athletes or non-athletes. In order to avoid this, PA of the subjects in this study was rigorously evaluated, which allowed an unequivocal characterization of the groups.
TABLE VII.-Comparison of continuous-wave Doppler to CDS.
To evaluate the PA questionnaires, physiological measurements determined by cardiopulmonary exercise tests and anthropornetrical analyses 30 were used. The questionnaires proved to be low-cost and easily hcindled instruments that allowed a thorough analysis of the physical activity performed. In the studied groups, present and previous physical activity results showed that daily physical activity, frequency as well as years of practice were greater in the athlete group than in the sedentary group. Cardio-respiratory fitness evaluated through cardiopulmonary exercise tests allowed a precise study of the subjects’ performances during the treadmill test as well as analyses of cardio-circulatory parameters and maximum oxygen consumption.31 In the subjects of the indoor soccer team of Botucatu City, maximum oxygen consumption values were compatible with those of champion teams mentioned by Dantas et al.21 and Suva.22 Whereas in the nonathlete group, the mean values were consonants to the low level of PA performed by these subjects. Body percent fat in athletes was inferior to the body fat percent in sedentary subjects, which represented the regular physical activity of soccer players. Based on these evaluations, it can be concluded that the subjects of the indoor soccer team showed well-defined characteristics of athletes whereas sedentary subjects, in fact, formed the non-athlete group.
The indoor soccer team was chosen as athlete group due to the large number of individuals who practice it in Brazil, which made recruiting volunteers easier. The Botucatu team, in particular, had an adequate and regular level of practice, which made its inclusion unquestionable as athletes of high performance. Besides that, it is interesting for the study of the popliteal artery compression the fact that this practice uses inferior limb muscles intensely. It is possible that the recruitment of athletes who practice other sports such as weight lifting, judo or Volleyball in which a greater muscle hypertrophy can be observed,32 could result in a higher frequency of positive results. Therefore, other studies to evaluate the influence of these sports in the frequency of positional popliteal compression are necessary.
The frequency of positive results in this study, identified in 14% of the subjects, were expressively lower when compared to the studies of Erdoes et al. 14 (53%) and Huffman et al. 15 (88%). This difference occurred despite the similarity of methods used: CDS was used to identify popliteal artery compression during provocation maneuvers of active flexion-extension of the foot; duplex scans were similar and the investigators were experienced. In Hoffman et al.15 study, in particular, active plantar flexion-extension maneuvers were performed against a commercially available resistance scale vertically positioned at the feet and that measured the force used by the subject during maneuvers. This technique was an improvement of the methodology, but it could not separately account for the high percentage of positional popliteal artery compression identified by these authors. Eventually, the participation in the study of athletes who performed different kinds of physical activity may have influenced higher frequency results, however, such fact would not explain the alterations in positional popliteal artery compression found in most sedentary subjects. A multi-centered study using large samples to disperse these frequency differences and to better define their true results is necessary.
The mean of skin fold values taken at the thigh and the right leg of athletes was smaller than that of non-athletes (p=0.01), which indicated a smaller quantity of local fat. As the perimetry evaluated in these extremities was similar in both groups, we could imagine muscle hypertrophy in the athletes. However, more accurate studies visualizing the transversal plane of the inferior limb with MRI or computerized tomography to identify more precisely muscle composition of these extremities should be made.33 There were no important differences between the groups studied (p=0.21) when positional popliteal artery compression was investigated with CDS. Therefore, regular physical activity and greater muscle hypertrophy of the inferior limbs in the athlete group in this study did not interfere in positive results.
In 1974, Darling et al.34 used continuous wave Doppler as initial eveiluation test of the posterior tibial artery in patients with suggestive symptoms of PAES. According to these authors, the presence of alterations in the pattern of the curve during Doppler examination, described as a reduction in the curve amplitude during maneuvers would indicate the suspicion of proximal popliteal stenosis. Based on this description, Doppler examinations started to be largely used in the postoperative control of patients with PAES as well as in the diagnosis of popliteal entrapment.3, 4, 6 In order to observe the correlation of these non-invasive diagnostic methods, this study evaluated sensitivity, specificity, and accuracy of continuous wave Doppler and of ABI, having the visualization of the popliteal compression with CDS as gold standard of evaluation. The results indicated good levels of correspondence between Doppler and ABI with positional popliteal compression detected with CDS. As these examinations have a lower cost compared to the other diagnostic methods, their use could be suggested in the initial screening of individuals suspected of having PAES. It should be emphasized that in this study all identified alterations in the Doppler curve were considered (amplitude reduction, irregularities in the peak of high systolic speed, monophase curve).22 However, technical difficulties in obtaining the flow signal at the posterior tibial artery due to probe deviation caused by muscular contraction during maneuvers, as well as false positive results caused by extrinsic compressions of the leg arteries which would occur bellow the soleus ring, could limit these evaluations.29,35
Arteriography and MRI are used to diagnose and select those requiring surgical treatment of PAES as they identify popliteal compression during provocation maneuvers as well as surrounding structures involved in the entrapment.3, 7, 14 With the arrival of CDS, a precise non-invasive cheaper evaluation in subjects suspected of having PAES was possible. Di Marzo et al.36 observed a good correlation between CDS, arteriography, and internal surgical results of individuals with popliteal entrapment. Erdoes et al. 14 verified that among positive CDS results in asymptomatic subjects, 60% were identified with MRI. The authors believed that, despite being precise in visualizing the artery’s surrounding structures, MRI showed limitations in identifying artery compression as the subject had to remain 6 minutes in continuous muscular contraction (during maneuvers), which produced artifacts in the visualization of the popliteal artery. This fact associated to the high cost of MRI would limit its use. It is possible that faster and modern MRI equipment does not have this technical limitation. Cormier et al.37 and Fermand et al.38 recommended the use of CDS as it is noninvasive and produces a detailed and dynamic study of the popliteal artery. As it became known, CDS started to be used in the diagnosis of patients suspected of having PAES as well as in studies of positional popliteal artery compression in a normal population. In this study, CDS evaluation in B mode produced good visualization of the popliteal artery and surrounding structures, which allowed th\e identification of important occlusion or stenosis of the artery during provocation maneuvers. Besides that, using color Doppler and curve spectral continuous-wave Doppler, it was possible to identify characteristics of the curves of proximal and distal arterial flow and the arterial stenosis, whirling, and alterations in their speed.
The present study shows that a large number of normal asymptomatic individuals may have examination findings compatible with positional occlusion of the popliteal artery.14,15 Rignault et al.9 described that these alterations would be similar to the compression of the subclavian vessels by scapular waist in the outlet syndrome. In both cases, the neurovascular bundle is intimately delimited by bone and surrounding tendinous-muscular structures in a relatively restricted space. Any deviation or hypertrophy of these structures could lead to arterial compressions. It is unknown, however, whether this compression would cause any pathological lesion. Tumipseed et al.10 reported, “No clinical evidence exists Lo support the concept that functional entrapment, in the absence of any clinical symptoms, requires a surgical intervention”. Porter,39 in 1999, wrote that the “positional popliteal artery occlusion is normal and should not be used to diagnose abnormal conditions”.
On the other hand, several authors 2,40 described histologie alterations of the popliteal artery in PAES and showed that they were similar to alterations in arteries that suffered repetitive extrinsic trauma of their wall, and that they could occur, therefore, in the anatomical or functional type of the disease. Levien et al.2 reported 3 cases of popliteal artery thrombosis due to chronic extrinsic trauma of the wall in subjects with functional PAES. Therefore, it can be assumed that the extrinsic compression of the popliteal artery, without anatomical alterations, may eventually indicate risk of lesion of the vascular wall and thrombosis.
The reason why some individuals with positional popliteal compression are symptomatic and others are not is unknown. However, it should be emphasized that the presence of symptoms is important in choosing the treatment of functional PAES. In the literature, all patients described with symptoms of functional entrapment practiced sports regularly as a common characteristic. Based on these facts, Melo et al.41 suggested that physical activity could be a determinant for the onset of symptoms. On the other hand, it is possible that some normal individuals with positional occlusion of the popliteal artery may be asymptomatic as their physical activity is insufficient for the onset of clinical complaints. However, they could have typical symptoms of functional PAES when practicing stronger physical activities. Therefore, although physical activity does not interfere with the frequency of positional compression of the popliteal artery, it could determine the onset of symptoms in these individuals.
In view of the results obtained in this study, the presence of extrinsic compression of the popliteal artery was demonstrated in 14% of the evaluated subjects during active plantar flexion- extension maneuvers. These subjects were asymptomatic and did not have anatomical alterations. In the diagnosis of this compression Doppler and ABI showed a good correlation with CDS and therefore could be used in screening examinations. Not only are they non- invasive, but also have a lower cost. It was also observed that indoor soccer practice did not interfere in the frequency of these alterations. Long-term consequences of the positional compression of the popliteal artery in these individuals remain uncertain. Observational studies and clinical follow-ups of these individuals are suggested to understand the real meaning of the positional compression of the popliteal artery in the future.
Acknowledgments.-We gratefully acknowledge Prof Dr Nathanael Ribeiro de MeIo, Dr Daniel Habberman, Vascular Ultrasonograph laboratory of School of Medicine of Botucatu and the Associao Atltica Botucatuense’s indoor soccer players.
The authors worked in the Non-invasive Vascular Laboratory, School of Medicine of Botucatu, “Estadual Paulista” University and the physical activity evaluations was done in Personal Med Clinic.
This original article was presented at:
– First Congress of the Latin American Chapter of the International Union of Angiology. Third Latin American Venous Forum. Brazil. April 9-12, 2003. Belo Horizonte, Brazil.
– First Meeting “So Paulo” of Vascular Surgery. April 4-5, 2003. So Paulo, Brazil.
This original article was partially financed by the Surgery and Orthopedics Department, School of Medicine of Botucatu – UNESP, Botucatu, Brazil.
Received January 14, 2004, Accepted for publication February 19, 2004.
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M. J. DE ALMEIDA 1, W. BONETTI YOSHIDA 1, D. HABBERMAN 2, E. M. MEDEIROS 3 M. GIANNINI 1, N. RIBEIRO DE MELO 4
1 Department of Surgery and Orthopedics, Medical School of Botucatu, UNESP, Botucatu, Brazil
2 Personal Med Clinic, Botucatu, Brazil
3 Ultra-Rad Clinic, Manila, SP, Brazil
4 Department of Surgery at FAMEMA, Medical School of Manila, SP, Brazil
Address reprint requests to: M. J. de Almeida, Rua Professor Francisco Morato 135, CEP17501-020, Marlia, Brazil. E-mail: [email protected]
Copyright Edizioni Minerva Medica Sep 2004
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