Introdução: Um dos fatores mais comuns de falha do procedimento das angioplastias vasculares periféricas é a estenose recorrente (reestenose). A inflamação vascular após angioplastia e implante de stent desempenha papel importante na proliferação de células do músculo liso vascular e posterior crescimento de neoíntima hipertrófica. Diversos estudos têm sugerido que a superfície dos stents, quando impregnada com determinadas moléculas, pode limitar a reestenose de forma eficaz. O carbono diamante, polímero de hidrocarboneto amorfo, pode ser usado para essa finalidade, reduzindo liberação de íons metálicos e a trombogenicidade. Diversos mediadores têm sido implicados na resposta inflamatória vascular, como o sistema calicreína-cinina (SCC), as citocinas, proteína C reativa (PCR) e o óxido nítrico (NO). Portanto, estudos clínicos específicos correlacionando o implante do stent aos níveis séricos destes possíveis marcadores podem contribuir no entendimento desse processo. Objetivo: Estudar a perviedade do dispositivo e a evolução clínica de doentes submetidos a angioplastia com stents impregandos de carbono no território vascular periférico, assim como o comportamento de mediadores séricos envolvidos nas fases mais precoces do processo inflamatório pós angioplastia. População e Método: Estudo prospectivo envolvendo 32 pacientes submetidos à angioplastia com stent no segmento ilíacofêmoro-poplíteo, selecionados no Ambulatório de Cirurgia Vascular e Endovascular do HCFMRP/USP. Foram tratadas lesões estenosantes ou oclusivas com angioplastia e colocação de stents de nitinol, com superfície impregnada de carbono (Carbostent®). Foram estudados os seguintes marcadores: SCC - com quantificação dos substratos (cininogênio de alto e baixo peso molecular - CAPM / CBPM) e das enzimas calicreína plasmática e tecidual, além da quantificação da cininase II; a determinação dos níveis de nitrito e nitratos para a avaliação de óxido nítrico; dosagem sérica de PCR e citocinas (IL-1 beta, IL-6, IL-8, IL-10, TNF-alfa e TGFbeta). Também foi realizado a dosagem dos leucócitos. Amostras séricas foram coletadas antes, 24 horas e 6 meses após o implante do stent. Os pacientes foram seguidos por um ano, para avaliação da perviedade nesse período. Resultados: Dos 27 pacientes que completaram seis meses de estudo, houve apenas uma reestenose (3,7%) e nenhuma oclusão (96,3% de perviedade). No período de um ano, quatro pacientes perderam seguimento e todos os 23 doentes avaliados, mantiveram a perviedade dos stents, com exceção do paciente no qual houve reestenose no tempo seis meses. Houve redução significativa das concentrações das citocinas inflamatórias (IL-1 beta, IL-6, IL-8 e TNF-?) no tempo 24 horas e seis meses quando comparado com o pré-procedimento (p<0,05); exceto a IL-8 no tempo 24 horas. As citocinas anti-inflamatórias (IL10 e TGF-beta) comportaram-se de maneira antagônica, com elevação do TGF-beta no tempo 24 horas e elevação, tanto do TGF-beta quanto da IL-10, no tempo 6 meses versus pré-tratamento e 6 meses versus 24 horas (P<0,05). A PCR apresentou queda no tempo seis meses em relação ao tempo 24h (p<0,05). Os níveis de NO não se alteraram entre os tempos; os de leucócitos elevaram-se no tempo 24 horas e reduziram-se no tempo seis meses em relação ao tempo 24 horas (p<0,05). Conclusão: No presente estudo a taxa de reestenose precoce foi de 3,7% nos primeiros 6 meses e 5% em 12 meses de seguimento. O comportamento dos marcadores inflamatórios evidenciou sua correlação direta com o processo de angioplastia e implante de carbostent, em especial o SCC, as citocinas, PCR e os leucócitos. Contudo, não foi possível relacionar a variação dos seus níveis séricos com o processo de reestenose. / Background: One of the most common factors of failure of the peripheral vascular angioplasty procedure is recurrent stenosis (restenosis). Vascular inflammation following angioplasty and stent implantation plays an important role in vascular smooth muscle cell proliferation and subsequent hypertrophic neointimal growth. Several studies have suggested that the surface of stents, when impregnated with certain molecules, can limit restenosis effectively. Diamond carbon, amorphous hydrocarbon polymer, can be used for this purpose, reducing release of metal ions and thrombogenicity. Several mediators have been implicated in the vascular inflammatory response, such as the kallikrein-kinin system (SCC), cytokines, C-reactive protein (CRP) and nitric oxide (NO). Therefore, specific clinical studies correlating stent implantation with serum levels of these possible markers may contribute to the understanding of this process. Objective: To study the patency of the device and the clinical evolution of patients undergoing angioplasty with carbon-impregnated stents in the peripheral vascular territory, as well as the behavior of serum mediators involved in the earlier stages of the inflammatory process after angioplasty. Population and Method: Prospective study involving 32 patients submitted to angioplasty with stent in the iliac-femoro-popliteal segment, selected at the HCFMRP / USP Outpatient Vascular and Endovascular Outpatient Clinic. Stenosis or occlusive lesions were treated with angioplasty and placement of nitinol stents with a carbon impregnated surface (Carbostent®). The following markers were studied: SCC - with quantification of substrates (high and low molecular weight cincinogens - HMWC / LMWC) and plasma and tissue kallikrein enzymes, besides quantification of kininase II; determination of nitrite and nitrate levels for the evaluation of nitric oxide; serum levels of CRP and cytokines (IL-1 beta, IL-6, IL-8, IL-10, TNF-a and TGF-b). Leucocytes were also dosed. Serum samples were collected before, 24 hours and 6 months after stent implantation. The patients were followed for one year to assess the patency in this period. Results: Of the 27 patients who completed six months of study, there was only one restenosis (3.7%) and no occlusion (96.3% of patency). In one year, four patients lost follow-up and all 23 patients evaluated, maintained stent patency, with the exception of the patient who had restenosis over time for six months. There was a significant reduction in the concentrations of inflammatory cytokines (IL-1 b, IL-6, IL-8 and TNF-a) in the time 24 hours and six months when compared with the pre-procedure (p <0.05); except for IL-8 in the 24 hour time. Anti-inflammatory cytokines (IL10 and TGF-b) behaved in an antagonistic manner, with TGF-b elevation in the 24 hour time and elevation of both TGF-b and IL-10, at 6 months versus pre- treatment and 6 months versus 24 hours (P <0.05). CRP showed a decrease in time six months in relation to time 24h (p <0.05). NO levels did not change between the times; the leukocytes increased in time 24 hours and reduced in time six months in relation to time 24 hours (p <0.05). Conclusion: In the present study, the rate of early restenosis was 3.7% in the first 6 months and 5% in 12 months of follow-up. The behavior of the inflammatory markers showed its direct correlation with the angioplasty and carbostent implantation process, especially SCC, cytokines, CRP and leukocytes. However, it was not possible to relate the variation of their serum levels to the restenosis process.

Vascular stents have become a standard for treating atherosclerosis due to distinct advantages in trauma and cost with other surgical techniques. Unfortunately, the therapy is hindered by the risk of a new blockage (termed restenosis) developing in the treated artery. Clinical studies have indicated that stent design is a major risk factor for restenosis, with failure rates varying from 20 to 40% for bare metal stents. Subsequently, there has been a significant effort devoted to reducing failure rates by covering stents in polymer coatings in which anti-proliferative drugs are embedded, however complications have arisen (e.g. incomplete endothelization, lack of success in peripheral arteries, lack of long-term follow-up studies) that have limited the success of this technology. It has been thought that restenosis is directly related to the mechanical conditions that vascular stents create. Moreover, it has been hypothesized that stents that induce higher non-physiologic stresses result in a more aggressive pathobiological response that can lead to restenosis development. In this study, a combination of computational modeling and in vivo analysis were conducted to investigate the artery stent-induced wall stresses, and subsequent biological inflammatory response. In particular, variations in stent design were investigated as a means of examining specific stent design criteria that minimize the mechanical impact of stenting. Collectively, these data indicate that stent designs that subject the artery wall to higher stress values result in significantly more neointimal tissue proliferation, therefore, confirming the aforementioned hypothesis. Moreover, this work provides valuable insight into the role that biomechanics can play in improving the success rate of this percutaneous therapy and overall patient care.

Atherosclerosis is the number one cause of death in the United States and one of the most common treatments is the implantation of a stent. In order to eliminate the two most common complications - restenosis and thrombosis - a novel covered stent is investigated. A covered stent membrane should be able to undergo large stretch, prevent restenosis, and be relatively non-thrombogenic. Polyvinyl alcohol (PVA) cryogels are examined as a candidate material for covered stent membranes. Mechanical testing included uniaxial tensile testing, puncture testing, and the fabrication and expansion of PVA cryogel covered stents. Uniaxial testing showed PVA cryogels to have sufficient ultimate stretch which was similar to bare metal stents during deployment. Puncture testing revealed that PVA cryogels are not likely to puncture in vivo. No tears were seen in the PVA cryogel membrane after expansion of the covered stents. Finite element analysis was used to determine a PVA cryogel membrane's effect on artery wall stress. PVA cryogel covered stents reduced both artery wall stress and tissue prolapse when compared to equivalent uncovered stents. Migration assays were used to determine if PVA cryogels are able to block the smooth muscle cell migration seen during restenosis. PVA cryogels significantly reduced cellular migration in modified Boyden chambers - suggesting that they would be able to prevent restenosis in vivo. Thrombogenicity was tested in vitro with a gravity-fed flow loop using porcine blood and in vivo with a sheep model. PVA cryogels were found to be less thrombogenic than polyester controls with the flow loop system. The sheep study demonstrated the feasibility of implanting PVA cryogel covered stents and good early patency. After explantation, the PVA cryogel membranes were intact - providing in vivo evidence for the durability of PVA cryogel covered stents. Overall, this work provides evidence that covered stents made with PVA cryogels are a feasible device in terms of their mechanics, ability to prevent restenosis, and low thrombogenicity. This work represents a major advancement in the development of PVA cryogel covered stents and provides necessary safety and feasibility data for future clinical trials.

Ο σκοπός της παρούσας διπλωματικής εργασίας ήταν να διερευνήσει την ενδεχόμενη συσχέτιση του γενετικού πολυμορφισμού -308 (G→A) του προαγωγέα (promoter) του γονιδίου του TNFα με την κλινική υποτροπή ή αγγειογραφική επαναστένωση, σε 40 Έλληνες ασθενείς μετά από αγγειοπλα-στική των στεφανιαίων αρτηριών (PTCA). Στη μελέτη περιελήφθησε και ένας πληθυσμός 30 υγιών μαρτύ-ρων. Η παρούσα μελέτη αποσκοπούσε ακριβώς στο να διερευνήσει τη συχνότητα της κλινικής υποτροπής ή αγγειογρα-φικής επαναστένωσης 6-8 μήνες μετά από PTCA, σε πληθυσ-μούς της περιοχής μας σε σχέση με το γονότυπο των ασθενών αυτών για το παραπάνω γονίδιο. Η πλειοψηφία των ασθενών 95% (38/40) ήταν ομόζυγοι για τον άγριο τύπο W του αλληλομόρφου και είχαν τον γονότυπο WW, 5% (2/40) ήταν ετεροζυγώτες WM, ενώ δεν ανευρέθησαν ομοζυγώτες MM για τον πολυμορφισμό. Στο δείγμα των 30 υγιών μαρτύρων, 90% (27/30) ήταν ομόζυγοι για τον άγριο τύπο W του αλληλομόρφου και είχαν τον γονότυπο WW, 10% (3/30) ήταν ετεροζυγώτες WM, ενώ δεν ανευρέθησαν ομοζυ-γώτες MM για τον πολυμορφισμό. Αγγειογραφική επαναστέ-νωση συνέβη σε 7 (οι 6/7 ασθενείς έχουν WW γονότυπο και ο 1/7 έχει τον WM γονότυπο) από τους 40 ασθενείς. Στην παρούσα μελέτη, δεν παρατηρήθηκε στατιστικά σημαντική συσχέτιση του -308 γενετικού πολυμορφισμού του TNFα με την αγγειογραφική επαναστένωση ή την κλινική υποτροπή μετά από αγγειοπλαστική των στεφανιαίων αρτηριών (PTCA), δείχνοντας ότι ο -308 γενετικός πολυμορφισμός του TNFα δεν είναι από μόνος του ένας βασικός παράγοντας κινδύνου, τουλάχιστον στον Ελλαδικό πληθυσμό με στεφανιαία νόσο. Βέβαια, τα αρνητικά μας ευρήματα σχετίζονται άμεσα με τη χαμηλή συχνότητα εμφάνισης του συγκεκριμένου πολυμορφισμού στους διάφορους πληθυσμούς, αλλά και με τον πολύ μικρό αριθμό ατόμων των παρατηρήσεων. / A follow-up study was conducted to investigate whether -308 genetic polymorphism of TNF-α gene was associated with the increased risk of restenosis in 40 Greek coronary artery disease patients undergoing coronary angioplasty and stent implanta-tion. For comparison of genotype frequency, a control group of 30 asymptomatic individuals was also studied. The end-point of the current study was the incidence of restenosis at 6-8 months of clinical follow-up. The majority of patients (38/40) had the WW genotype (homozygous for the wild-no polymorphic type allele) and only 2/40 patients had the WM genotype (heterozygous). Patients homozygous for the polymorphism (MM genotype) were not found. The frequency distribution was not different from that of the control subjects. Restenosis occurred in 7 of the 40 patients. In the population studied, -308 genetic polymorphism of TNF-α gene was not found to predispose patients to an increased incidence of restenosis. Nevertheless, these findings should be considered as preliminary, taking into account the small number of patients that were studied and the rarity of the -308 genetic polymorphism of TNF-α gene.

No description available.

Mechanical stresses and flow dynamics alteration in a stented artery region are known to stimulate intimal thickening and increase the risk of restenosis, the closure of a revascularized artery. Particle imaging velocimetry (PIV) is an optical flow visualization technique that can be used to characterize the local flow dynamics around different stent structures. However, the usual cylindrical stent geometries present visualization difficulties when using an optical measurement technique such as the PIV technique. Using a flat configuration of a stent model presents advantages over the usual cylindrical model. A planar stent model makes data acquisition easier in planes cutting through the model due to its flat geometry that is compatible with the PIV planar flow investigation technique. Furthermore, with the planar stent configuration model velocity measurements and their associated flow features can be done without inducing refraction of the laser light sheet occurring with the cylindrical model's curvature. The refraction of light should be avoided since measurement errors and reflections are the resulting effects of this laser light plane deviation when passing through the curvature of a cylindrical stent model. / The spatial and temporal distribution of the Wall Shear Stress (WSS), which is believed to be of primary importance in the development of restenosis should be comparable between the flat and the cylindrical stent configuration models. The velocity and shear strain rate distributions will be compared between the flat and cylindrical stent configurations using computational fluid dynamics (CFD) simulations in order to analyse the feasibility of using a flat instead of a cylindrical version of the stent model for PIV experiments. It will be shown that for a physiological pulsatile flow the flat model yields results in shear strain rate spatial and temporal distribution that is comparable to the cylindrical model. A more PIV compatible, efficient and less refractive error prone validated flat model would be advantageous when several stent designs influence on the local hemodynamics around the strut geometries have to be studied quantitatively and optimized.

Η επαναστένωση των στεφανιαίων αρτηριών μετά από αγγειοπλαστική αποτελεί μια συχνή επιπλοκή, που αναπαριστά την επουλωτική απόκριση του αρτηριακού τοιχώματος στο μηχανικό τραυματισμό. Οι στατίνες σταθεροποιούν τις αθηρωματικές πλάκες, αφενός μειώνοντας τα λιπίδια και τη θρομβογενητικότητά τους και αφετέρου μέσω της αντιφλεγμονώδους δράσης τους και της βελτίωσης της ενδοθηλιακής λειτουργίας. Πρόσφατες πειραματικές μελέτες αποδεικνύουν ότι η ιβαμπραδίνη ελαττώνοντας την καρδιακή συχνότητα συντελεί στη μείωση του μεγέθους της αθηρωματικής πλάκας . Πρωταρχικός σκοπός της παρούσας μελέτης είναι η ανάπτυξη ενός καινοτόμου και ασφαλούς μοντέλου διωτιαίας επαγωγής μηχανικού τραυματισμού στην κατιούσα θωρακική αορτή κονίκλων Νέας Ζηλανδίας, διατρεφόμενων με υπερχοληστερολαιμική δίαιτα, ως εναλλακτικό μοντέλο προσομοίωσης της επαναστένωσης των στεφανιαίων αγγείων. Επιπλέον, η μελέτη αυτή σχεδιάστηκε για να καθορίσει αν η υπερχοληστερολαιμική δίαιτα προάγει την εξέλιξη αυθόρμητων και επαγόμενων από αγγειοπλαστική αθηρωματικών βλαβών και αν η σιμβαστατίνη και η ιβαμπραδίνη αναστέλλουν περαιτέρω την αθηρωμάτωση και την επαναστένωση. Υλικό-μέθοδοι: Τα πειραματόζωα τυχαιοποιήθηκαν σε 2 πειραματικά πρωτόκολλα, που περιλάμβαναν 40 κονίκλους το καθένα, ανάλογα με το αν επρόκειτο να υποβληθούν σε μηχανικό τραυματισμό ή όχι. Εν συνεχεία, οι κόνικλοι του κάθε πειραματικού πρωτοκόλλου τυχαιοποιήθηκαν σε 4 ομάδες που περιλάμβαναν 10 ζώα η καθεμιά ως εξής: ομάδα Α- ομάδα αθηρογενετικής δίαιτας (4% δίαιτα εμπλουτισμένη σε χοληστερόλη), ομάδα Β- αθηρογενετική δίαιτα σε συνδυασμό με σιμβαστατίνη (5 mg/kg/day) ομάδα Γ- αθηρογενετική δίαιτα σε συνδυασμό με ιβαμπραδίνη (5 mg/kg/day) και ομάδα Δ – αθηρογενετική δίαιτα σε συνδυασμό με ταυτόχρονη χορήγηση σιμβαστατίνης (5mg/kg/day) και ιβαμπραδίνης (5 mg/kg/day) για 9 εβδομάδες. Μία εβδομάδα αργότερα, διάστημα ικανοποιητικό για την αύξηση των επιπέδων της χοληστερόλης τα πειραματόζωα του πειραματικού πρωτοκόλλου Ι υποβλήθηκαν σε τραυματισμό με μπαλόνι της κατιούσας θωρακικής αορτής μέσω διαδερμικού καθετηριασμού της ωτιαίας αρτηρίας. Στο τέλος των 9 εβδομάδων έγινε ευθανασία των κονίκλων, εκτομή της ανιούσας και της κατιούσας θωρακικής αορτής και ιστολογική / ανοσοϊστοχημική αξιολόγηση με αντισώματα έναντι των αφρωδών μακροφάγων (RAM 11) και της α-ακτίνης λείων μυϊκών κυττάρων (HHF-35). Ενώ, τμήμα της τραυματισθείσας κατιούσας αορτής καταψύχθηκε για μοριακή εκτίμηση της νίτρωσης των πρωτεϊνών με Western Blot. Τέλος, έγινε ιστομορφομετρική ποσοτικοποίηση της υπερπλασίας του νέου έσω χιτώνα και προσδιορισμός του λόγου έσω /μέσου χιτώνα , της αυλικής και της συνολικής περιοχής του αγγείου με το λογισμικό Image J. Αποτελέσματα: Οι τραυματισθείσες κατιούσες αορτές ανέδειξαν ιστολογικά σοβαρότερες αθηρωματικές βλάβες και σημαντική αύξηση του λόγου έσω /μέσου χιτώνα σε σύγκριση με τις μη τραυματισθείσες. Η χορήγηση σιμβαστατίνης πέρα από την ελάττωση των επιπέδων της χοληστερόλης, οδήγησε σε σημαντική ελάττωση του αριθμού των αφρωδών μακροφάγων και των SMCs και σε περαιτέρω αναστολή των αυθόρμητων και των επαγόμενων από αγγειοπλαστική αθηρωματικών βλαβών. Επιπλέον, η σιμβαστατίνη οδήγησε σε σημαντική ελάττωση της υπερπλασίας του έσω χιτώνα και του λόγου έσω /μέσου χιτώνα στις τραυματισθείσες και μη τραυματισθείσες αορτές. Ενώ, η σιμβαστατίνη ανέστειλε σημαντικά την ελάττωση της περιοχής του αυλού και της συνολικής περιοχής της τραυματισθείσας αορτής, διατηρώντας το αγγειακό τοίχωμα σε επίπεδο αντίστοιχο με το φυσιολογικό. Η ιβαμπραδίνη εμφάνισε σημαντική ελάττωση των αφρωδών μακροφάγων στις αυθόρμητες και επαγόμενες από αγγειοπλαστική αθηρωματικές βλάβες, αποκαλύπτοντας μικρότερη αποτελεσματικότητα τη σιμβαστατίνη. Η ιβαμπραδίνη δεν κατόρθωσε να ελαττώσει σημαντικά τον αριθμό των SMCs στις αυθόρμητες βλάβες της ανιούσας και στις επαγόμενες από αγγειοπλαστική αθηρωματικές βλάβες της τραυματισθείσας κατιούσας αορτής. Ωστόσο, εμφάνισε σημαντική ελάττωση των SMCs στις μη τραυματισθείσες κατιούσες αορτές. Η ιβαμπραδίνη ανέστειλε την επαγωγή σοβαρών αυθόρμητων και επαγόμενων από αγγειοπλαστική βλαβών και ελάττωσε σημαντικά την υπερπλασία του έσω χιτώνα και του λόγου έσω / μέσου χιτώνα. Ωστόσο, η ιβαμπραδίνη αποκάλυψε σημαντική απώλεια του αυλού και της συνολικής περιοχής του τραυματισθέντος αγγείου παρά την ελάττωση της υπερπλασίας του έσω χιτώνα. Σε μοριακό επίπεδο η σιμβαστατίνη και η ιβαμπραδίνη ανέστειλαν την επαγόμενη από χοληστερόλη καθώς και την επαγόμενη από χοληστερόλη και αγγειοπλαστική νίτρωση σε θέση τυροσίνης των πρωτεϊνών σε εκχυλίσματα κατιούσας αορτής. Συμπεράσματα: Η σιμβαστατίνη και η ιβαμπραδίνη ανέστειλαν την αθηρογένεση στις τραυματισθείσες με μπαλόνι και μη τραυματισθείσες αορτές υπερλιπιδαιμικών κονίκλων. Ειδικότερα, η σιμβαστατίνη και η ιβαμπραδίνη ανέστειλαν την υπερπλασία του έσω χιτώνα και σε μοριακό επίπεδο ελάττωσαν το οξειδωτικό στρες. Καινοτόμο εύρημα της μελέτης αποτελεί η προστατευτική δράση της σιμβαστατίνης στη διατήρηση του αυλού και στην αναστολή της περιοριστικής αναδιαμόρφωσης του αγγείου, μετά από τραυματισμό με μπαλόνι. Η ιβαμπραδίνη αποκάλυψε σημαντική απώλεια του αυλού και επαγωγή της αρνητικής αναδιαμόρφωσης του αγγείου μετά από τραυματισμό με μπαλόνι. Στο σημείο αυτό πρέπει να τονιστεί η δυνητική ευεργετική δράση της ιβαμπραδίνης στην αναστολή της επαναστένωσης μετά από τοποθέτηση stent, όπου η υπερπλασία του έσω χιτώνα αποτελεί το μοναδικό μηχανισμό επαναστένωσης. Συνεπώς, η σιμβαστατίνη και ιβαμπραδίνη δυνητικά κατέχουν ανασταλτικό ρόλο στην επαναστένωση των στεφανιαίων μετά από τοποθέτηση stent, εύρημα που χρήζει περαιτέρω τεκμηρίωση με κλινικές μελέτες. / Coronary post- angioplasty restenosis constitutes a common complication, depicting arterial wall healing response to mechanical injury. Statins stabilize atherosclerotic plaques either by reducing their lipids levels’ and their thrombogenicity or by restoring endothelial function through anti-inflammatory action. Recent studies demonstrate that ivabradine via heart rate reduction contributes to the reduction of atherosclerotic plaque size. Primary aim of this study is the demonstration of an innovative and safe model of transauricular balloon angioplasty in the descending thoracic aorta of high-cholesterol fed rabbits, as an alternative model of coronary restenosis simulation. In addition, this study was designed to determine if hypercholesterolemic diet promotes the development of spontaneous and angioplasty-induced atherosclerotic lesions and further if simvastatin and ivabradine inhibit atherogenesis and restenosis progression. Materials and Methods: Rabbits randomized in two experimental protocols of 40 animals each, based on the mechanical injury induction or not. Rabbits of each experimental protocol further randomized to 4 groups of 10 animals each, as follows: group A or group of atherogenic diet (4% hypercholesterolemic diet), group B or group of atherogenic diet plus simvastatin (5 mg/kg/day), group C or group of atherogenic diet plus ivabradine (5 mg/kg/day), and group D or group of atherogenic diet plus simvastatin (5 mg/kg/day) combined with ivabradine (5 mg/kg/day) for 9 weeks. A week later, after the sufficient elevation of cholesterol levels, rabbits of experimental protocol I underwent transauricular balloon angioplasty of descending aorta. At the end of 9 weeks, rabbits euthanisized and ascending and descending aortas removed for further histological and immunochemical evaluation with a foam macrophage antibody (RAM-11) and a SMCs a-actin antibody (HHF-35). Furthermore, a segment of descending aortas was frozen for the Western Blot evaluation of protein tyrosine nitration. Also, histomorphometric quantification of intimal thickening, intima /media ratio, lumen and total vessel area was performed using Image J software. Results: Injured thoracic aortas revealed more severe histological lesions and further more significant increase of intima/media ratio compared to non-injured. Beyond its lipid lowering effect, simvastatin resulted in significant reduction of the amount of foam cells and SMCs and further inhibition of spontaneous and angioplasty induced lesions. Moreover, simvastatin reduced significantly intimal thickening and intima / media ratio in both injured and non-injured aortas. Also, simvastatin inhibited significantly the lumen and total vessel reduction after balloon angioplasty. Ivabradine revealed a significant reduction of foam cells in spontaneous and angioplasty induced atherosclerotic lesions, showing less effectiveness compared with simvastatin. Ivabradine did not attempt to reduce significantly the number of SMCs in spontaneous lesions of ascending aortas and in angioplasty-induced lesions, respectively. While, ivabradine reduced significantly the amount of SMCs in non-injured descending aortas. Ivabradine inhibited the development of severe spontaneous and angioplasty-induced atherosclerotic lesions as well as intimal thickening and intima/media ratio. Despite the inhibition of intimal hyperplasia, ivabradine revealed a significant lumen and total vessel area reduction. In molecular level simvastatin and ivabradine inhibited both the cholesterol and cholesterol/ angioplasty induction of tyrosine nitration in proteins of descending aortas. Conclusions: Both simvastatin and ivabradine inhibited atherogenesis in injured and non-injured aortas of hyperlipidemic rabbits. Specifically, simvastatin and ivabradine inhibited intimal thickening and further reduced oxidation stress in molecular level. Innovative finding of the study constitutes the protective effect of simvastatin, concerning the lumen restoration and further the inhibition of constrictive remodelling after balloon angioplasty. Ivabradine revealed a significant lumen loss and further induction of constrictive remodelling after balloon angioplasty. However, it should be noted the potential beneficial impact of ivabradine on restenosis inhibition after stent deployment, as intimal hyperplasia comprises the only mechanism of restenosis in this case. Consequently, simvastatin and ivabradine possess a potentially inhibitory role in coronary restenosis after stent deployment, fact that should be further documented with clinical trials.

OBJETIVO: analisar, por meio da morfometria digital, o espessamento intimal presente na artéria ilíaca de suínos, submetidos à angioplastia isoladamente e à angioplastia seguida do implante de stent. MATERIAIS E MÉTODOS: em dez suínos sadios, foi realizada a angioplastia de ambas as artérias ilíacas comuns (AIC) seguida do implante de um “Z” stent autoexpansível na AIC esquerda. Após quatro semanas, os animais foram sacrificados para a retirada de amostras de tecido arterial e preparo das lâminas histológicas de três grupos de peças de cada suíno divididas do seguinte modo: grupo 1, envolvendo o segmento arterial proximal do stent; grupo 2, envolvendo o segmento distal do stent; grupo 3, área da angioplastia da AIC direita. As imagens das lâminas foram digitalizadas e analisadas por programa de morfometria com cálculo da área luminal, área da camada íntima e área da camada média dos cortes histológicos. A análise estatística foi realizada através de média e desvio padrão das áreas em cada grupo, utilizando ANOVA, com teste Post-Hoc de Tukey e LSD. O valor de p≤0,05 foi considerado significativo. RESULTADOS: na análise das médias das áreas obtidas, foi encontrada uma diferença estatisticamente significativa quanto à camada íntima dos grupos 1 (5,41 mm²) e 2 (5,25 mm²), quando comparados ao grupo 3 (0,65 mm²), em relação à camada média dos grupos 1 (3,51 mm²) e 2 (3,70 mm²), quando comparados ao grupo 3 (5,59 mm²) e não se observou diferença significativa nas médias das áreas luminais dos três grupos (grupo 1: 6,63 mm²; grupo 2: 5,25 mm²; grupo 3: 5,78 mm²). CONCLUSÃO: a angioplastia da AIC do suíno, seguida do implante do stent, gerou um espessamento intimal maior do que aquele produzido apenas pela angioplastia; porém, a área da camada média apresentou-se diminuída nos grupos “angioplastia + stent”; a luz arterial não apresentou diferença entre estes grupos. / PURPOSE: to compare through digital morphometry, the intimal thickening of the ilíac arteries in pigs, submitted to isolated angioplasty and angioplasty followed by stent implantation. MATERIAL AND METHODS: the angioplasty was performed in 10 healthy pigs in both common ilac arteries (CIA), followed by a self-expanding stainless steel “Z” stent implantation in the left CIA. After four weeks, the animals where sacrificed and the aorto-iliac segment was dissected free of surrounding structures. Histologic slices where divided in three groups: left CIA in the area of the proximal implantation site of the stent (group 1), left CIA including the distal implantation site of the stent (group 2) and the region of angioplasty in the right CIA (group 3). The histological slices were digitalized to be analysed by morphometry with calculation of the luminal, intimal and media layers areas. Descriptive statistics analysis was performed through average and standard deviation of areas on each group, using ANOVA, with Tukey and LSD Post-Hoc tests. The value of p≤0.05 were considered significant. RESULTS: a significant statistic difference was observed when the median area of intimal layer of the groups 1 (5.41 mm²) and 2 (5.25 mm²) were compared with group 3 (0.65 mm²) and in the media layer area of the groups 1 (3.51 mm²) and 2 (3.70 mm²) when compared with group 3 (5.59 mm²). No difference was observed in luminal areas among the three groups (group 1: 6.63 mm²; group 2: 5.25 mm²; group 3: 5.78 mm²). CONCLUSION: angioplasty followed by stent insertion produces an intimal thickening bigger than that observed after simple angioplasty; however, the area of the media layer is smaller in the “angioplasty plus stent” groups; there is no significant change in the luminal area among the three groups.

OBJETIVO: analisar, por meio da morfometria digital, o espessamento intimal presente na artéria ilíaca de suínos, submetidos à angioplastia isoladamente e à angioplastia seguida do implante de stent. MATERIAIS E MÉTODOS: em dez suínos sadios, foi realizada a angioplastia de ambas as artérias ilíacas comuns (AIC) seguida do implante de um “Z” stent autoexpansível na AIC esquerda. Após quatro semanas, os animais foram sacrificados para a retirada de amostras de tecido arterial e preparo das lâminas histológicas de três grupos de peças de cada suíno divididas do seguinte modo: grupo 1, envolvendo o segmento arterial proximal do stent; grupo 2, envolvendo o segmento distal do stent; grupo 3, área da angioplastia da AIC direita. As imagens das lâminas foram digitalizadas e analisadas por programa de morfometria com cálculo da área luminal, área da camada íntima e área da camada média dos cortes histológicos. A análise estatística foi realizada através de média e desvio padrão das áreas em cada grupo, utilizando ANOVA, com teste Post-Hoc de Tukey e LSD. O valor de p≤0,05 foi considerado significativo. RESULTADOS: na análise das médias das áreas obtidas, foi encontrada uma diferença estatisticamente significativa quanto à camada íntima dos grupos 1 (5,41 mm²) e 2 (5,25 mm²), quando comparados ao grupo 3 (0,65 mm²), em relação à camada média dos grupos 1 (3,51 mm²) e 2 (3,70 mm²), quando comparados ao grupo 3 (5,59 mm²) e não se observou diferença significativa nas médias das áreas luminais dos três grupos (grupo 1: 6,63 mm²; grupo 2: 5,25 mm²; grupo 3: 5,78 mm²). CONCLUSÃO: a angioplastia da AIC do suíno, seguida do implante do stent, gerou um espessamento intimal maior do que aquele produzido apenas pela angioplastia; porém, a área da camada média apresentou-se diminuída nos grupos “angioplastia + stent”; a luz arterial não apresentou diferença entre estes grupos. / PURPOSE: to compare through digital morphometry, the intimal thickening of the ilíac arteries in pigs, submitted to isolated angioplasty and angioplasty followed by stent implantation. MATERIAL AND METHODS: the angioplasty was performed in 10 healthy pigs in both common ilac arteries (CIA), followed by a self-expanding stainless steel “Z” stent implantation in the left CIA. After four weeks, the animals where sacrificed and the aorto-iliac segment was dissected free of surrounding structures. Histologic slices where divided in three groups: left CIA in the area of the proximal implantation site of the stent (group 1), left CIA including the distal implantation site of the stent (group 2) and the region of angioplasty in the right CIA (group 3). The histological slices were digitalized to be analysed by morphometry with calculation of the luminal, intimal and media layers areas. Descriptive statistics analysis was performed through average and standard deviation of areas on each group, using ANOVA, with Tukey and LSD Post-Hoc tests. The value of p≤0.05 were considered significant. RESULTS: a significant statistic difference was observed when the median area of intimal layer of the groups 1 (5.41 mm²) and 2 (5.25 mm²) were compared with group 3 (0.65 mm²) and in the media layer area of the groups 1 (3.51 mm²) and 2 (3.70 mm²) when compared with group 3 (5.59 mm²). No difference was observed in luminal areas among the three groups (group 1: 6.63 mm²; group 2: 5.25 mm²; group 3: 5.78 mm²). CONCLUSION: angioplasty followed by stent insertion produces an intimal thickening bigger than that observed after simple angioplasty; however, the area of the media layer is smaller in the “angioplasty plus stent” groups; there is no significant change in the luminal area among the three groups.

Introdução: Um dos fatores mais comuns de falha do procedimento das angioplastias vasculares periféricas é a estenose recorrente (reestenose). A inflamação vascular após angioplastia e implante de stent desempenha papel importante na proliferação de células do músculo liso vascular e posterior crescimento de neoíntima hipertrófica. Diversos estudos têm sugerido que a superfície dos stents, quando impregnada com determinadas moléculas, pode limitar a reestenose de forma eficaz. O carbono diamante, polímero de hidrocarboneto amorfo, pode ser usado para essa finalidade, reduzindo liberação de íons metálicos e a trombogenicidade. Diversos mediadores têm sido implicados na resposta inflamatória vascular, como o sistema calicreína-cinina (SCC), as citocinas, proteína C reativa (PCR) e o óxido nítrico (NO). Portanto, estudos clínicos específicos correlacionando o implante do stent aos níveis séricos destes possíveis marcadores podem contribuir no entendimento desse processo. Objetivo: Estudar a perviedade do dispositivo e a evolução clínica de doentes submetidos a angioplastia com stents impregandos de carbono no território vascular periférico, assim como o comportamento de mediadores séricos envolvidos nas fases mais precoces do processo inflamatório pós angioplastia. População e Método: Estudo prospectivo envolvendo 32 pacientes submetidos à angioplastia com stent no segmento ilíacofêmoro-poplíteo, selecionados no Ambulatório de Cirurgia Vascular e Endovascular do HCFMRP/USP. Foram tratadas lesões estenosantes ou oclusivas com angioplastia e colocação de stents de nitinol, com superfície impregnada de carbono (Carbostent®). Foram estudados os seguintes marcadores: SCC - com quantificação dos substratos (cininogênio de alto e baixo peso molecular - CAPM / CBPM) e das enzimas calicreína plasmática e tecidual, além da quantificação da cininase II; a determinação dos níveis de nitrito e nitratos para a avaliação de óxido nítrico; dosagem sérica de PCR e citocinas (IL-1 beta, IL-6, IL-8, IL-10, TNF-alfa e TGFbeta). Também foi realizado a dosagem dos leucócitos. Amostras séricas foram coletadas antes, 24 horas e 6 meses após o implante do stent. Os pacientes foram seguidos por um ano, para avaliação da perviedade nesse período. Resultados: Dos 27 pacientes que completaram seis meses de estudo, houve apenas uma reestenose (3,7%) e nenhuma oclusão (96,3% de perviedade). No período de um ano, quatro pacientes perderam seguimento e todos os 23 doentes avaliados, mantiveram a perviedade dos stents, com exceção do paciente no qual houve reestenose no tempo seis meses. Houve redução significativa das concentrações das citocinas inflamatórias (IL-1 beta, IL-6, IL-8 e TNF-?) no tempo 24 horas e seis meses quando comparado com o pré-procedimento (p<0,05); exceto a IL-8 no tempo 24 horas. As citocinas anti-inflamatórias (IL10 e TGF-beta) comportaram-se de maneira antagônica, com elevação do TGF-beta no tempo 24 horas e elevação, tanto do TGF-beta quanto da IL-10, no tempo 6 meses versus pré-tratamento e 6 meses versus 24 horas (P<0,05). A PCR apresentou queda no tempo seis meses em relação ao tempo 24h (p<0,05). Os níveis de NO não se alteraram entre os tempos; os de leucócitos elevaram-se no tempo 24 horas e reduziram-se no tempo seis meses em relação ao tempo 24 horas (p<0,05). Conclusão: No presente estudo a taxa de reestenose precoce foi de 3,7% nos primeiros 6 meses e 5% em 12 meses de seguimento. O comportamento dos marcadores inflamatórios evidenciou sua correlação direta com o processo de angioplastia e implante de carbostent, em especial o SCC, as citocinas, PCR e os leucócitos. Contudo, não foi possível relacionar a variação dos seus níveis séricos com o processo de reestenose. / Background: One of the most common factors of failure of the peripheral vascular angioplasty procedure is recurrent stenosis (restenosis). Vascular inflammation following angioplasty and stent implantation plays an important role in vascular smooth muscle cell proliferation and subsequent hypertrophic neointimal growth. Several studies have suggested that the surface of stents, when impregnated with certain molecules, can limit restenosis effectively. Diamond carbon, amorphous hydrocarbon polymer, can be used for this purpose, reducing release of metal ions and thrombogenicity. Several mediators have been implicated in the vascular inflammatory response, such as the kallikrein-kinin system (SCC), cytokines, C-reactive protein (CRP) and nitric oxide (NO). Therefore, specific clinical studies correlating stent implantation with serum levels of these possible markers may contribute to the understanding of this process. Objective: To study the patency of the device and the clinical evolution of patients undergoing angioplasty with carbon-impregnated stents in the peripheral vascular territory, as well as the behavior of serum mediators involved in the earlier stages of the inflammatory process after angioplasty. Population and Method: Prospective study involving 32 patients submitted to angioplasty with stent in the iliac-femoro-popliteal segment, selected at the HCFMRP / USP Outpatient Vascular and Endovascular Outpatient Clinic. Stenosis or occlusive lesions were treated with angioplasty and placement of nitinol stents with a carbon impregnated surface (Carbostent®). The following markers were studied: SCC - with quantification of substrates (high and low molecular weight cincinogens - HMWC / LMWC) and plasma and tissue kallikrein enzymes, besides quantification of kininase II; determination of nitrite and nitrate levels for the evaluation of nitric oxide; serum levels of CRP and cytokines (IL-1 beta, IL-6, IL-8, IL-10, TNF-a and TGF-b). Leucocytes were also dosed. Serum samples were collected before, 24 hours and 6 months after stent implantation. The patients were followed for one year to assess the patency in this period. Results: Of the 27 patients who completed six months of study, there was only one restenosis (3.7%) and no occlusion (96.3% of patency). In one year, four patients lost follow-up and all 23 patients evaluated, maintained stent patency, with the exception of the patient who had restenosis over time for six months. There was a significant reduction in the concentrations of inflammatory cytokines (IL-1 b, IL-6, IL-8 and TNF-a) in the time 24 hours and six months when compared with the pre-procedure (p <0.05); except for IL-8 in the 24 hour time. Anti-inflammatory cytokines (IL10 and TGF-b) behaved in an antagonistic manner, with TGF-b elevation in the 24 hour time and elevation of both TGF-b and IL-10, at 6 months versus pre- treatment and 6 months versus 24 hours (P <0.05). CRP showed a decrease in time six months in relation to time 24h (p <0.05). NO levels did not change between the times; the leukocytes increased in time 24 hours and reduced in time six months in relation to time 24 hours (p <0.05). Conclusion: In the present study, the rate of early restenosis was 3.7% in the first 6 months and 5% in 12 months of follow-up. The behavior of the inflammatory markers showed its direct correlation with the angioplasty and carbostent implantation process, especially SCC, cytokines, CRP and leukocytes. However, it was not possible to relate the variation of their serum levels to the restenosis process.