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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Compressão extrínseca da artéria poplítea em indivíduos assintomáticos atletas e não atletas /

Almeida, Marcelo José de. January 2003 (has links)
Orientador: Winston Bonetti Yoshida / Resumo: A Síndrome do Aprisionamento da Artéria Poplítea (SAAP) é uma doença caracterizada pela compressão extrínseca dessa artéria, causada pelo desvio de seu trajeto anatômico habitual ou por estruturas músculo-tendinosas da fossa poplítea. Os sintomas clínicos costumam aparecer quando os indivíduos realizam esforços físicos. Distinguem-se dois tipos de SAAP: a clássica ou congênita e a funcional ou adquirida. Na forma clássica, distúrbios do desenvolvimento embrionário provocam anomalias da artéria poplítea ou de estruturas adjacentes que ocasionam a compressão. Na forma funcional ou adquirida, identifica-se apenas hipertrofia dos músculos gastrocnêmios como possível causa do encarceramento. O diagnóstico, em ambos os tipos, é feito pela detecção de oclusão ou estenose significativa da artéria poplítea às manobras de dorsiflexão e hiperextensão ativa dos pés, utilizando-se o mapeamento dúplex, a ressonância magnética ou a arteriografia. A identificação desses testes positivos em indivíduos assintomáticos e sem alterações anatômicas, trouxe questionamentos a respeito da especificidade dos testes diagnósticos. Neste trabalho é feita uma revisão da SAAP anatômica e funcional, além de serem discutidas a acurácia, sensibilidade e especificidade dos testes diagnósticos em cada caso. / Abstract: The popliteal artery entrapment syndrome (PAES) is characterized by extrinsic compression of this artery as a result of anatomic deviation from its usual course, or by compression from musculotendinous structures in the popliteal fossa. Clinical symptoms onset when these affect individuals are undergoing stressing exercise. There are two types of PAES: classical or congenital form, and a functional acquired form. In the classical form, disturbances in the embryogenesis lead either directly to popliteal artery anomalies or to alterations of adjacent structures which cause compression of the popliteal artery. In the functional form, hypertrophy of the gastrocnemius muscle secondary to exercise has been postulated as a cause. In both types, diagnosis is made in subjects, on finding total occlusion or important stenosis of the popliteal artery. This is identified by duplex scan, magnetic resonance or arteriography during active plantar flexion-extension. A positive test in non-symptomatic subjects presenting no anatomical anomalies led to discussion regarding its sensibility and specificity. A review of anatomical and functional PAES besides a discussion about accuracy, sensibility and specificity of those diagnostics tests was made in this study. / Mestre
2

Popliteal Artery Aneurysm : Epidemiology, Surgical Management and Outcome

Ravn, Hans January 2007 (has links)
<p>Even if popliteal artery aneurysm (PAA) is the most common peripheral aneurysm, no single surgeon or institution has enough patients to study this disease with appropriate scientific methods, and no population-based investigation exists. </p><p>PAA epidemiology, treatment, management, and outcome were studied in a population-based study of 571 patients (717 legs) primarily operated on for PAAs and 100 episodes of preoperative thrombolysis in Sweden between 1987 and 2002. Patients were identified in the Swedish Vascular Registry and case-records were reviewed. Information on amputation and survival was obtained for all patients, and 190 patients were re-examined with ultrasound, after mean 7.2 years (range 2-18)</p><p>Median age was 71 years; 5.8% were women. Patients with unilateral PAA had AAA in 28%, increasing to 38% when PAAs were bilateral. Crude survival was 91.4% at one and 70% at five years, significantly lower than among age and sex matched controls. The cumulative incidence for operation of PAA in Sweden was estimated to 8.3/million person year. One-year amputation-rate was 8.8 %, increasing to 11% after follow-up (7.2 years). Independent risk factors for amputation within one year were poor run-off, age, emergency procedure, and prosthetic graft. Run-off was improved by preoperative thrombolysis among 87% of legs, when acute ischemia. After surgical repair with a medial approach the risk of late expansion of the aneurysm was 33%, with a posterior approach 8% , p=0.014. Among 190 re-examined patients, 108 (57%) had at least one additional aneurysm at index-operation, increasing to 131 (68%) at re-examination, the total number of aneurysms increasing by 42% (from 244 to 346).</p><p>Conclusions: Multiple aneurysms are common among patients operated on for PAA. Preoperative thrombolysis improves run-off and decreases the amputation-rate in PAAs with acute ischemia. Vein grafts do better than prosthetic grafts, especially when a long bypass is needed. Posterior approach, when possible, reduces the risk of late expansion. A complete examination of the aorto-iliac and femoro-popliteal arteries is warranted at the time of surgery. All patients should be kept under life-long surveillance in order to detect and treat newly developed aneurysms timely. Normal arterial segments should be re-examined after three years.</p>
3

Popliteal Artery Aneurysm : Epidemiology, Surgical Management and Outcome

Ravn, Hans January 2007 (has links)
Even if popliteal artery aneurysm (PAA) is the most common peripheral aneurysm, no single surgeon or institution has enough patients to study this disease with appropriate scientific methods, and no population-based investigation exists. PAA epidemiology, treatment, management, and outcome were studied in a population-based study of 571 patients (717 legs) primarily operated on for PAAs and 100 episodes of preoperative thrombolysis in Sweden between 1987 and 2002. Patients were identified in the Swedish Vascular Registry and case-records were reviewed. Information on amputation and survival was obtained for all patients, and 190 patients were re-examined with ultrasound, after mean 7.2 years (range 2-18) Median age was 71 years; 5.8% were women. Patients with unilateral PAA had AAA in 28%, increasing to 38% when PAAs were bilateral. Crude survival was 91.4% at one and 70% at five years, significantly lower than among age and sex matched controls. The cumulative incidence for operation of PAA in Sweden was estimated to 8.3/million person year. One-year amputation-rate was 8.8 %, increasing to 11% after follow-up (7.2 years). Independent risk factors for amputation within one year were poor run-off, age, emergency procedure, and prosthetic graft. Run-off was improved by preoperative thrombolysis among 87% of legs, when acute ischemia. After surgical repair with a medial approach the risk of late expansion of the aneurysm was 33%, with a posterior approach 8% , p=0.014. Among 190 re-examined patients, 108 (57%) had at least one additional aneurysm at index-operation, increasing to 131 (68%) at re-examination, the total number of aneurysms increasing by 42% (from 244 to 346). Conclusions: Multiple aneurysms are common among patients operated on for PAA. Preoperative thrombolysis improves run-off and decreases the amputation-rate in PAAs with acute ischemia. Vein grafts do better than prosthetic grafts, especially when a long bypass is needed. Posterior approach, when possible, reduces the risk of late expansion. A complete examination of the aorto-iliac and femoro-popliteal arteries is warranted at the time of surgery. All patients should be kept under life-long surveillance in order to detect and treat newly developed aneurysms timely. Normal arterial segments should be re-examined after three years.
4

Compressão extrínseca da artéria poplítea em indivíduos assintomáticos atletas e não atletas

Almeida, Marcelo José de [UNESP] January 2003 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:22:50Z (GMT). No. of bitstreams: 0 Previous issue date: 2003Bitstream added on 2014-06-13T20:09:57Z : No. of bitstreams: 1 almeida_mj_me_botfm.pdf: 1055929 bytes, checksum: 094af3d450a40ed69470b19fce7d47b7 (MD5) / A Síndrome do Aprisionamento da Artéria Poplítea (SAAP) é uma doença caracterizada pela compressão extrínseca dessa artéria, causada pelo desvio de seu trajeto anatômico habitual ou por estruturas músculo-tendinosas da fossa poplítea. Os sintomas clínicos costumam aparecer quando os indivíduos realizam esforços físicos. Distinguem-se dois tipos de SAAP: a clássica ou congênita e a funcional ou adquirida. Na forma clássica, distúrbios do desenvolvimento embrionário provocam anomalias da artéria poplítea ou de estruturas adjacentes que ocasionam a compressão. Na forma funcional ou adquirida, identifica-se apenas hipertrofia dos músculos gastrocnêmios como possível causa do encarceramento. O diagnóstico, em ambos os tipos, é feito pela detecção de oclusão ou estenose significativa da artéria poplítea às manobras de dorsiflexão e hiperextensão ativa dos pés, utilizando-se o mapeamento dúplex, a ressonância magnética ou a arteriografia. A identificação desses testes positivos em indivíduos assintomáticos e sem alterações anatômicas, trouxe questionamentos a respeito da especificidade dos testes diagnósticos. Neste trabalho é feita uma revisão da SAAP anatômica e funcional, além de serem discutidas a acurácia, sensibilidade e especificidade dos testes diagnósticos em cada caso. / The popliteal artery entrapment syndrome (PAES) is characterized by extrinsic compression of this artery as a result of anatomic deviation from its usual course, or by compression from musculotendinous structures in the popliteal fossa. Clinical symptoms onset when these affect individuals are undergoing stressing exercise. There are two types of PAES: classical or congenital form, and a functional acquired form. In the classical form, disturbances in the embryogenesis lead either directly to popliteal artery anomalies or to alterations of adjacent structures which cause compression of the popliteal artery. In the functional form, hypertrophy of the gastrocnemius muscle secondary to exercise has been postulated as a cause. In both types, diagnosis is made in subjects, on finding total occlusion or important stenosis of the popliteal artery. This is identified by duplex scan, magnetic resonance or arteriography during active plantar flexion-extension. A positive test in non-symptomatic subjects presenting no anatomical anomalies led to discussion regarding its sensibility and specificity. A review of anatomical and functional PAES besides a discussion about accuracy, sensibility and specificity of those diagnostics tests was made in this study.
5

Influencia das variações posturais sobre as forças hemodinamicas e a sua correlação com a espessura intima-media das arterias carotidas e popliteas / Postural changes, hemodynamics forces and correlation with intima-media thickness of carotid and popliteal arteries

Gemignani, Tiago, 1976- 14 August 2008 (has links)
Orientador: Wilson Nadruz Junior / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas / Made available in DSpace on 2018-08-11T18:42:20Z (GMT). No. of bitstreams: 1 Gemignani_Tiago_M.pdf: 1392345 bytes, checksum: 25697107f179a8a592c3843115eec95e (MD5) Previous issue date: 2008 / Resumo: A aterosclerose de artérias periféricas tipicamente afeta vasos dos membros inferiores, sugerindo que estímulos locais tenham função importante neste processo. O presente estudo avaliou os efeitos das mudanças posturais na tensão circunferencial das artérias poplítea e carótida e investigou a correlação entre a tensão circunferencial vascular local e a espessura íntima-média destas artérias. Cento e dezessete indivíduos não diabéticos, não hipertensos, não fumantes foram avaliados (48 homens e 69 mulheres). A pressão arterial foi mensurada em braço e panturilha dos pacientes, nas posições supina e ortostática. Análise com Eco-Doppler foi realizada em artérias carótida comum e poplítea após medida de pressão arterial. A tensão circunferencial foi calculada de acordo com a Lei de Laplace. Foi encontrado que a mudança da posição supina para a ortostática aumentou a tensão circunferencial poplítea, mas não em artérias carótidas. Análises de correlação parcial, ajustadas por idade e índice de massa corpórea, revelaram que os valores de tensão circunferencial média obtidos em posição supina e ortostática exibiram correlação similar com a espessura íntima-média carotídea, enquanto que a tensão circunferencial sistólica ortostática revelou correlação mais forte com a espessura íntima-média poplítea, que a tensão circunferencial obtida em posição supina. Estes resultados foram confirmados após análise de regressão múltipla incluindo idade, sexo, índice de massa corpórea e níveis de lípides e glicemia como variáveis independentes. Em conclusão, a tensão circunferencial ortostática foi melhor preditor hemodinâmico da espessura íntima-média poplítea do que a tensão circunferencial supina. Estes dados sugerem que a posição ereta seja um fator de risco potencial para aterosclerose poplítea devido ao aumento da sobrecarga hemodinâmica local. / Abstract: Atherosclerosis of peripheral arteries typically affects vessels of the lower limbs, suggesting that local hemodynamic stimuli play a role in this process. The present study evaluated the effects of body posture changes on carotid and popliteal circumferential wall tension (CWT) and investigated the relationship between local CWT and intima-media thickness (IMT) of these arteries. One hundred seventeen nondiabetic, nonhypertensive, nonsmoker subjects (48 men and 69 women) were evaluated. Blood pressure was measured in the arm and calf of subjects in supine and orthostatic positions. Echo-Doppler analysis evaluated the common carotid and popliteal arteries after blood pressure measurements. CWT was calculated according to Laplace's law. Changing from supine to orthostatic posture increased CWT in popliteal but not in carotid arteries. Partial correlation analysis controlled for age and body mass index revealed that supine and orthostatic CWT exhibited comparable correlation coefficients with carotid IMT, while orthostatic CWT displayed a stronger relationship with popliteal IMT than supine CWT. These results were further confirmed by multiple linear regression analysis including age, sex, body mass index, lipid fractions and glucose as independent variables. Orthostatic CWT is a better hemodynamic predictor of popliteal IMT in comparison to supine CWT. These data suggest that orthostatic posture may be a potential risk factor for popliteal atherosclerosis by increasing local hemodynamic burden. / Mestrado / Clinica Medica / Mestre em Clinica Medica
6

Tensão circunferencial poplítea em posição ortostática se associa à presença local de aterosclerose em pacientes com fatores de risco cardiovascular / Popliteal circumferencial wall tension induced by orthostatic body posture is associated with local atherosclerotic plaques in patients with cardiovascular risk factors.

Gemignani, Tiago, 1976- 22 August 2018 (has links)
Orientador: Wilson Nadruz Junior / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-22T09:54:44Z (GMT). No. of bitstreams: 1 Gemignani_Tiago_D.pdf: 3089084 bytes, checksum: aedee263d43b0d61197caea8058ed566 (MD5) Previous issue date: 2013 / Resumo: As artérias dos membros inferiores são submetidas a uma maior sobrecarga hemodinâmica na posição ortostática. Este estudo avaliou os efeitos da variação postural sobre a tensão circunferencial na parede das artérias poplíteas, carótidas e braquiais, bem como investigou a correlação entre a tensão circunferencial e a presença de placas ateroscleróticas nestas artérias em uma população com fatores de risco cardiovascular. Duzentos e três indivíduos (118 mulheres e 85 homens) com fatores de risco cardiovascular (tabagismo, hipertensão arterial e diabetes mellitus) foram estudados clínica e laboratorialmente, sendo a pressão arterial mensurada nos braços e panturrilhas, tanto em posição supina como ortostática. As artérias foram avaliadas por ultrassonografia, enquanto a tensão circunferencial foi calculada de acordo com a Lei de Laplace. Nos indivíduos participantes, observou-se a presença de placas ateroscleróticas em 47%, 29% e 0% das artérias poplíteas, carótidas e braquiais, respectivamente. As medidas de tensão circunferencial em artérias carótidas não foram associadas à presença de placas ateroscleróticas após ajuste pelas variáveis confundidoras. Por outro lado, as análises de regressão logística e de modelo linear geral mostraram, após ajuste pelas variáveis confundidoras, que a tensão circunferencial sistólica ortostática foi o único parâmetro hemodinâmico local que demonstrou correlação significativa com placas ateroscleróticas poplíteas em toda amostra estudada. Na análise específica por sexos, apesar da correlação positiva com a presença de placas ateroscleróticas poplíteas em ambos os sexos, a tensão circunferencial sistólica ortostática exibiu associação independente com placas ateroscleróticas somente em mulheres, após ajuste pelas variáveis confundidoras. Em conclusão, a tensão circunferencial ortostática poplítea e não a em posição supina, é associada com placas ateroscleróticas em artérias poplíteas, particularmente em mulheres. Estes dados sugerem que a posição ortostática pode desempenhar uma função importante na aterogênese das artérias dos membros inferiores, modificando as forças hemodinâmicas locais, podendo, contudo, haver diferença entre os sexos / Abstract: Lower limb arteries are exposed to higher hemodynamic burden in erectile posture. This study evaluated the effects of body posture on popliteal, carotid and brachial circumferential wall tension (CWT) and investigated the relationship between local CWT and atherosclerotic plaques in subjects with cardiovascular risk factors. Two hundred and three subjects (118 women and 85 men) with cardiovascular risk factors (smoking, hypertension or diabetes mellitus) underwent clinical and laboratory analysis and had their blood pressure measured in the arm and calf in supine and orthostatic positions. Arteries were evaluated by ultrasound analysis, while CWT was calculated according to Laplace's law. Among the enrolled participants, 47%, 29% and none presented popliteal, carotid and brachial plaques, respectively. Carotid CWT measurements were not associated with local plaques after adjustment for potential confounders. Conversely, general linear model and logistic regression analyses adjusted for potential confounders demonstrated that peak orthostatic CWT was the only local hemodynamic parameter showing significant relationship with popliteal plaques in the whole sample. In gender-specific analyses, although positively correlated with popliteal plaques in both genders, local peak orthostatic CWT exhibited an independent association with popliteal plaques after adjustment for potential confounders only in women. In conclusion, popliteal CWT measured in orthostatic posture, rather than in supine position, is associated with popliteal atherosclerotic plaques, particularly in women. These findings suggest that orthostatic posture might play a role in the atherogenesis of leg arteries by modifying local hemodynamic forces and that there may be gender differences in this regard / Doutorado / Clinica Medica / Doutor em Clínica Médica
7

PHARMACOKINETIC MODELING OF DYNAMIC MR IMAGING IN THE KNEE OF CHILDREN WITH JUVENILE RHEUMATOID ARTHRITIS

WORKIE, DAGNACHEW WALELIGN 14 July 2005 (has links)
No description available.
8

Ενδοαγγειακή απεικόνιση των αγγείων κάτωθεν του βουβωνικού συνδέσμου με Οπτική Συνεκτική Τομογραφία (Optical Coherence Tomography)

Παρασκευόπουλος, Ιωάννης 18 June 2014 (has links)
Η οπτική συνεκτική τομογραφία με τη χρήση συχνοτήτων ( FD-OCT) είναι μια ενδαγγειακή απεικονιστική μέθοδος που χρησιμοποιεί εγγύς στο υπέρυθρο φως, για να παράγει υψηλής ανάλυσης εικόνες του τοιχώματος του αυλού του αγγείου. Όπως και στην τεχνολογία υπερήχων, εκπέμπεται φωτεινή ενέργεια η οποία ανακλάται και εξασθενεί, σύμφωνα με την υφή του προσπιπτομένου ιστού. Το OCT μπορεί να απεικονίσει, με ανάλυση από 10 έως 20 μm, μικροδομές του αγγειακού τοιχώματος με εξαίσια λεπτομέρεια. Μέχρι σήμερα, η δυνατότητα εφαρμογής της μεθόδου είχε περιοριστεί σε μικρές αρτηρίες διαμέτρου έως 4mm και δεν είχε εφαρμοστεί in vivo στα αγγεία των κάτω άκρων, κάτωθεν του επιπέδου των βουβώνων. Σκοπός της παρούσας μελέτης είναι να αναφερθεί για παγκοσμίως πρώτη φορά η ασφάλεια και η σκοπιμότητα της απεικόνισης με Οπτική Συνεκτική Τομογραφία του αρτηριακού άξονα των κάτω άκρων , κάτωθεν του επιπέδου της βουβώνας ( μηροϊγνυακός άξονας και κνημιαία αγγεία), καθώς και οι σχετιζόμενες με το FD-OCT επιπλοκές. Επιπρόσθετα, να διερευνηθούν για πρώτη φορά, με τη χρήση FD-OCT, τα χαρακτηριστικά του αγγειακού τοιχώματος του ανωτέρω άξονα (τόσο πριν όσο και μετά από αγγειοπλαστική ή/και τοποθέτηση stent), η μορφολογία της αθηρωματικής πλάκας, η μορφολογία και η ποσοτικοποίηση της υπερπλασίας του νέου εσωτερικού χιτώνα (neointima) εντός του stent, η επαναστένωση εντός του stent (ISR) και η κακή εναπόθεση (malapposition) των stent struts σε μια σειρά από ασθενείς που πάσχουν από περιφερική αρτηριοπάθεια (PAD). Μελετήθηκαν, με ποσοτική ανάλυση του αυλού τους (Quantitative vascular analysis), αρτηρίες με διάμετρο έως 7 χιλιοστά. Μικτά χαρακτηριστικά από περιοχές πλούσιες σε λιπίδια, εναποθέσεις ασβεστίου και ασβεστοποιημένες πλάκες, νεκρωτικές περιοχές και ίνωση εντοπίστηκαν σε όλες τις απεικονιζόμενες αθηροσκληρωτικές βλάβες. Ωστόσο, με βάση το επικρατέστερο από τα παραπάνω απεικονιστικά χαρακτηριστικά, οι βλάβες στο πλαίσιο της έρευνας ταξινομήθηκαν ως αμιγώς ινωτικές, ως ινοασβεστοποιημένες, ως πλούσιες σε λιπίδια και τέλος ως νεκρωτικές/ασβεστοποιημένες. Συσσώρευση των μακροφάγων εντός της αθηρωματικής πλάκας σημειώθηκε σε μικρό ποσοστό των de novo αθηρωματικών αλλοιώσεων. Ποικίλοι βαθμοί υπερπλασίας του νέου έσω χιτώνα απεικονίσθηκαν σε όλες τις περιπτώσεις ISR αλλοιώσεων, με καθαρά ινωτικά χαρακτηριστικά και σημαντική νεοαγγείωση σε κάποιες από αυτές. Η νεοαγγείωση συνέπεσε με το επίπεδο της μέγιστης στένωσης του αγγειακού αυλού. Σημαντικού βαθμού διαχωρισμός με μεγάλο περιορισμό του αγγειακού αυλού, τέτοιος ώστε να απαιτηθεί να τοποθετηθεί ενδοαυλικό stent, ανιχνεύθηκε σε αρκετές περιπτώσεις της de novo αθηρωμάτωσης. Η ψηφιακή αφαιρετική αγγειογραφία παρέλειψε να προσδιορίσει μεγάλο ποσοστό των σοβαρών διαχωρισμών μετά από αγγειοπλαστική. Η νεοαθηροσκλήρυνση εντός του νέου έσω χιτώνα των κνημιαίων φαρμακευτικών stents (DES), είναι ένα συχνό εύρημα τόσο στους συμπτωματικούς όσο και στους ασυμπτωματικούς ασθενείς. Μπορούμε να υποθέσουμε ότι, κατά αναλογία με τα εμφυτευμένα DES στα στεφανιαία αγγεία, η ελαττωματική ενδοθηλιοποίηση που προκαλείται από την εκλυόμενη φαρμακευτική ουσία, μαζί με την νεοαγγείωση που αναπτύσσεται μεταξύ των stent struts, μπορούν να υποδαυλίσουν την νεοαθηροσκλήρυνση εντός του νέου έσω χιτώνα των κνημιαίων DES, η οποία μπορεί να οδηγήσει σε επαναστένωση εντός του stent (ISR) και απώλεια του εμβαδού του αυλού των περιφερικών αρτηριών. Οι παρατηρήσεις της μελέτης αυτής θέτουν σε αμφισβήτηση το παραδοσιακό τρόπο κατανόησης της περιφερειακής επαναστένωσης εντός του stent ως μιας απλής υπερπολλαπλασιαστικής απάντησης στο βαρότραυμα. Η απεικόνιση με FD-OCT είναι ένα βέλτιστο πειραματικό εργαλείο για την αξιολόγηση της εξέλιξης της αθηροσκληρωματικής νόσου και την επαναστένωση του αγγείου. Μπορεί να παρέχει υψηλής ευκρίνειας ενδοαγγειακή απεικόνιση κατά τη διάρκεια αγγειοπλαστικών επεμβάσεων στα κάτω άκρα και θα μπορούσε να αποδειχθεί κλινικά χρήσιμο για τον προσδιορισμό της εντός του stent πρόπτωσης ιστού και του strut malapposition. Παρ 'όλα αυτά, δεν πρέπει να χρησιμοποιηθεί ως εργαλείο για τη συνήθη κλινική πρακτική μέχρι να προκύψουν στοιχεία από περαιτέρω κλινικές δοκιμές για τον καθορισμό των ειδικών ενδείξεων της απεικόνισης με FD-OCT στις περιφερικές αρτηρίες. / Optical coherence tomography (OCT) is a catheter-based imaging method that employs near-infrared light to produce high-resolution intravascular images. OCT can readily visualize vessel microstructure at a 10- to 20-μm resolution with exquisite detail. To date, however, applicability of the method has been limited to small diameter arteries (≤4 mm). To the best of the author’s knowledge, this study is the first worldwide that demonstrates the safety and clinical feasibility of frequency domain Optical Coherence Tomography (FD-OCT) imaging of infrainguinal vessels in vivo during infrainguinal angioplasty procedures. It is also the first study that reports the use of intravascular FD-OCT to detect and characterize in-stent neointimal tissue following infrapopliteal drug eluting stent (DES) placement in patients suffering from critical limb ischemia. Quantitative lumen analysis of arteries with diameter up to 7 mm was performed. High-resolution OCT images provided exquisite two-dimensional axial and longitudinal views of the infrainguinal arteries and allowed thorough investigation of a variety of angioplasty sequela, including and not limited to intimal tears and dissection flaps, white and red thrombus, stent mesh malapposition, and intrastent plaque prolapse. Of interest, OCT identified cases of suboptimal postangioplasty outcome that single-plane subtraction angiography did not recognize and accounted. Mixed features of lipid pool areas, calcium deposits and calcified plaques, necrotic areas, and fibrosis were identified in all of the imaged atherosclerotic lesions. However, based on the predominant baseline imaging findings, lesions under investigation were classified as purely fibrotic, fibrocalcific, mostly lipid-laden and necrotic/calcified. Intraplaque accumulation of macrophages was noted in some of de novo atheromatic lesions. Varying degrees of neointimal hyperplasia were demonstrated in all cases of in stent restenosis (ISR) lesions with purely fibrotic features and considerable neovascularization in some of them. The latter finding coincided with the level of maximum vessel stenosis in all cases. Neoatherosclerosis following infrapopliteal DES placement is a frequent finding in both symptomatic and asymptomatic patients. Our preliminary observations allow us to speculate that analogous to coronary implanted DES, defective endothelialization induced by the eluted drug, along with neovascularization developing between the stent struts, may incite neointimal neoatherosclerosis, which may result in ISR and lumen loss of the peripheral arteries. It also seems that infrapopliteal neoatherosclerosis may be a significant contributing factor for ISR rather than a minor and sporadic process, highlighting the clinical significance of the phenomenon. Our observations put in dispute the traditional way of understanding peripheral in-stent restenosis as a simple hyperproliferative response to barotraumas and may explain the paramount importance of aggressive risk factor modification strategies. Neointimal neoatherosclerosis as identified by FD-OCT may have a role in the development of below-the-knee restenosis and thus warrants further investigation by larger controlled studies. Moreover, it may prove clinically useful for the determination of intrastent tissue prolapse and strut malapposition. FD-OCT should not be utilized as a tool for routine clinical practice until evidence from further clinical trials emerge to determine the specific indications for OCT imaging of the peripheral arteries.

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