Although surgical and transcatheter interventions have significantly improved survival of patients with coarctation of the aorta (CoA) and interrupted aortic arch (IAA), long-term complications including left ventricular (LV) abnormalities and systemic arterial dysfunction remain issues of concern despite successful repair. While new indices of myocardial deformation that reflect diastolic and systolic function in terms of strain, strain rate, and torsion as detected by speckle tracking echocardiography have shown promise in the assessment of LV, left atrial (LA), and right ventricular (RV) mechanics, the understanding of ventricular myocardial deformation after repair of CoA is limited. In this thesis, studies were undertaken to test the hypotheses that LV, LA, and RV myocardial deformation is altered and related to structural and functional arterial alterations in adolescents and young adults late after successful intervention of CoA and IAA, and to explore the LV contractile reserve noninvasively by examining the force-frequency relationship (FFR) in these patients. The LV, LA, and RV mechanics were evaluated with tissue Doppler and speckle tracking echocardiography, while carotid arterial structure and function were determined by radiofrequency-based echocardiographic imaging and oscillometry techniques. Supine bicycle stress exercise testing was used to evaluate the FFR by tracking the changes in LV contractility with increase in heart rate. Patients after CoA and IAA repair had significantly greater carotid arterial stiffness and intima-media thickness when compared with controls. Furthermore, mitral annular systolic and diastolic velocities, LV longitudinal and radial strain and early diastolic strain rates, peak torsion and untwisting velocity, and LA peak positive and total strain, and LA strain rates at ventricular systole, early diastole, and atrial contraction were significantly lower in patients than controls. Increased arterial stiffness and intima-media thickness was associated with worse LV myocardial deformation, while LA total strain and LA strain rate at ventricular early diastole were associated with diastolic annular velocities and strain rates. Multivariate analysis further revealed arterial stiffness as an independent determinant of LA total strain. With regard to dynamic assessment of LV contractile reserve, at submaximal exercise, the systemic blood pressures were significantly greater in patients than controls, while mitral annular systolic and early diastolic velocities remained significantly reduced. The increase in LV myocardial isovolumic acceleration, a relative load independent index of contractility, with increase in heart rate during exercise stress was significantly reduced in patients compared with controls. Flattening of FFR in patients reflected impaired LV contractile reserve, which was found to be associated negatively with increment in systemic blood pressure during exercise. For RV mechanics, patients with CoA repaired exhibited significantly lower tricuspid annular systolic and early diastolic velocities, global RV systolic longitudinal strain, and strain rate during systole, early and late diastole, compared to controls. Impairment of RV deformation was further related to increased LV mass and RV thickness. In conclusion, these findings suggest arterial dysfunction, impaired LV, RV, and LA mechanics, and reduced LV contractile reserve, in patients late after CoA and IAA repair even in the absence of residual aortic narrowing and implicate abnormal arterial-LV-LA and LV-RV interactions. / published_or_final_version / Paediatrics and Adolescent Medicine / Master / Master of Philosophy

No description available.

Introduction: There is progressive stiffening and dilatation of the aorta and large elastic arteries with aging as a result of the repetitive cyclic stress they are exposed to throughout life. Aortic stiffening has a number of detrimental effects including an increase in aortic pulse wave velocity and early wave reflection, isolated systolic hypertension, ventricular-vascular mismatch, impaired coronary blood flow reserve, and is the fundamental cause of heart failure in the elderly. The aim of this thesis is to provide proof of concept for the aortic wrap procedure; a surgical treatment of stiffening and dilatation of the ascending aorta with aging. The surgical procedure involves wrapping an elastic material around the ascending aorta of elderly patients, to reduce the stiffness and diameter of the ascending aorta towards that seen in youth. Methods: Proof of concept is investigated in the following studies. 1. The effect of the elastic wrap on the in-vivo stiffness of the normal aorta. 2. The effect of the elastic wrap on the in-vivo stiffness of the dilated and stiffened aorta. 3. The effect of the elastic wrap on the in-vitro stiffness of the aged human ascending aorta and on aortic pressure. 4. The effect of wrapping the aged human ascending aorta on pulse pressure (mathematical model). 5. The effect of chronic implantation on the structure of the normal aorta. 6. The mechanical properties of the ovine thoracic aorta and the elastic wrap material. Results: 1. Elastic wrap application increased the in-vivo stiffness of the normal aorta. 2. Elastic wrap application decreased the stiffness of the stiffened and dilated aorta. 3. Elastic wrap application decreased the in-vitro stiffness of the elderly human ascending aorta and pulse pressure. 4. A reduction in ascending aortic stiffness was sufficient to reduce ascending aortic pulse pressure. Conclusion: Application of the elastic wrap to the aged human ascending aorta is expected to reduce aortic stiffness, as well as systolic and pulse pressure, and to increase diastolic pressure with a reduction in cardiac load. The aortic wrap procedure may be an effective surgical procedure for the treatment of heart failure and isolated systolic hypertension.

Renal failure in patients undergoing Aortic surgery is associated with a poor outcome. The shortcomings of serum creatinine for measuring renal function are well documented. We examined the value of alternative markers in diagnosing and predicting renal damage in patients undergoing abdominal aortic surgery and those exposed to intravascular contrast media. Cystatin C lacks some of the reservations associated with serum creatinine when used as a marker of glomerular filtration rate. The protease inhibitor alpha-glutathione Stransferase (a-GST) is recovered in urine after injury to proximal tubular cells. Urine microalbumin is a marker of glomerular permeability. Together we used all four assays to detect and characterize the nature of renal injury after surgery and contrast exposure. Cystatin C had a marginally better sensitivity than serum creatinine at detecting baseline renal impairment. It also showed earlier changes in individual patients whose renal dysfunction deteriorated over time. The urinary markers showed an earlier significant rise after the onset of surgery when compared to serum markers, but only a-GST rose significantly after contrast exposure. Patients undergoing a supra-renal cross-clamp showed significantly higher a-GST levels (and not the other three markers) when compared to the infra-renal group. Cystatin C appears to have better sensitivity and specificity for predicting the need for dialysis in patients undergoing surgery. Peak serum creatinine and cystatin C after contrast exposure show good correlation with peak values after surgery. Cystatin C is equivalent to and may be better than serum creatinine in detecting preexisting and deteriorating renal impairment. Although the urinary assays are earlier markers of renal injury, their clinical significance needs to be determined. Elevation in creatinine and cystatin C after contrast exposure parallel those after surgical intervention and may be helpful in selecting out high-risk patients prior to surgery. / Thesis (M.Med.Sc.)-University of Natal, 2003.

Made available in DSpace on 2014-06-11T19:31:32Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-08-03Bitstream added on 2014-06-13T20:22:22Z : No. of bitstreams: 1 rubira_cj_dr_botfm.pdf: 240856 bytes, checksum: 5f30f1a1d2ce6492fd56a190c587cfc5 (MD5) / Universidade Estadual Paulista (UNESP) / A Coarctação da aorta (CoA) é responsável por 5% a 7% das cardiopatias congênitas, com uma incidência de 0,3 a 0,4 por 1000 nascidos vivos. A cirurgia foi a única forma de terapia para CoA até 1982, quando a angioplastia tornou-se uma alternativa disponível para o seu tratamento. Recoarctação, aneurisma e dissecção da aorta permaneceram desvantagens de ambos os tratamentos. Para evitar estes inconvenientes, em 1990, endopróteses vasculares foram introduzidas para coarctação nativa e recoarctação e desde então, tornaramse uma abordagem alternativa. A melhor abordagem para o tratamento da CoA, se cirurgia aberta ou a colocação de endoprótese vascular, não está estabelecida. Analisar a efetividade e a segurança da colocação de endoprótese vascular em comparação com a cirurgia aberta em pacientes com CoA. O Grupo Peripheral Vascular Diseases da Cochrane realizou a busca em seu Registro Especializado (última busca Setembro de 2011) e na Central (2011, nº 3). Nós também procuramos em MEDLINE, EMBASE, CINAHL, AMED, Web of Science e LILACS (última busca em setembro de 2011). Foram avaliadas as referências encontradas e aplicados os critérios de inclusão para os estudos selecionados. Não houve restrição de linguagem. Ensaios clínicos controlados aleatorizados ou quase-aleatorizados que compararam pacientes com CoA submetidos a cirurgia aberta ou a colocação de endoprótese vascular. Os autores da revisão avaliaram independentemente os estudos identificados para a elegibilidade de inclusão. Nós excluímos estudos após reunião de consenso. Os critérios de seleção foram aplicados para avaliação do título e resumo de todos os estudos identificados. No total, foram selecionados cinco estudos para a análise de texto completo. Após avaliação detalhada, foram excluídos todos os estudos porque não havia... / Coarctation of the aorta (CoA) accounts for 5% to 7% of congenital heart disease, with an incidence of 0.3 to 0.4 per 1000 live births. Surgery was the only choice of therapy for CoA until 1982 when balloon angioplasty became an available alternative for its treatment. Re-coarctation, aneurysm and aortic dissection remain the disadvantages of both treatments. To avoid those disadvantages, in 1990 endovascular stents were introduced for native coarctation and re-coarctation and since then they have become an alternative approach to surgical repair. The best approach to treat the CoA, whether open surgery or by stent placement, is not clear. To analyze the effectiveness and safety of stent placement compared with open surgery in patients with coarctation of the thoracic aorta. The Cochrane Peripheral Vascular Diseases Group searched their Specialised Register (last searched September 2011) and CENTRAL (2011, Issue 3).We also searched MEDLINE, EMBASE, CINAHL, AMED, Web of Science and LILACS (last searched in September 2011). We evaluated the located references and applied the inclusion criteria to selected studies. There was no restriction on language. Randomized or quasi-randomized controlled clinical trials that compared patients with CoA undergoing open surgery or stent placement. The review authors independently assessed the studies identified for eligibility for inclusion. We excluded studies after a consensus meeting. All identified studies were screened and had the selection criteria applied to the title and abstract. In total, we selected five studies for full-text analysis. After detailed evaluation, we excluded all studies because there was no comparison between stent placement and open surgery. There is insufficient evidence with regards to the best treatment for coarctation of the thoracic aorta. This review... (Complete abstract click electronic access below)

Orientador: Paulo Eduardo de Oliveira Carvalho / Coorientador: Antônio José Maria Catâneo / Banca: Luiz Eduardo Villaça Leão / Banca: Marcos Augusto Moraes Silva / Banca: Olavo Ribeiro Rodrigues / Banca: Rúbio Bombonato / Resumo: A Coarctação da aorta (CoA) é responsável por 5% a 7% das cardiopatias congênitas, com uma incidência de 0,3 a 0,4 por 1000 nascidos vivos. A cirurgia foi a única forma de terapia para CoA até 1982, quando a angioplastia tornou-se uma alternativa disponível para o seu tratamento. Recoarctação, aneurisma e dissecção da aorta permaneceram desvantagens de ambos os tratamentos. Para evitar estes inconvenientes, em 1990, endopróteses vasculares foram introduzidas para coarctação nativa e recoarctação e desde então, tornaramse uma abordagem alternativa. A melhor abordagem para o tratamento da CoA, se cirurgia aberta ou a colocação de endoprótese vascular, não está estabelecida. Analisar a efetividade e a segurança da colocação de endoprótese vascular em comparação com a cirurgia aberta em pacientes com CoA. O Grupo Peripheral Vascular Diseases da Cochrane realizou a busca em seu Registro Especializado (última busca Setembro de 2011) e na Central (2011, nº 3). Nós também procuramos em MEDLINE, EMBASE, CINAHL, AMED, Web of Science e LILACS (última busca em setembro de 2011). Foram avaliadas as referências encontradas e aplicados os critérios de inclusão para os estudos selecionados. Não houve restrição de linguagem. Ensaios clínicos controlados aleatorizados ou quase-aleatorizados que compararam pacientes com CoA submetidos a cirurgia aberta ou a colocação de endoprótese vascular. Os autores da revisão avaliaram independentemente os estudos identificados para a elegibilidade de inclusão. Nós excluímos estudos após reunião de consenso. Os critérios de seleção foram aplicados para avaliação do título e resumo de todos os estudos identificados. No total, foram selecionados cinco estudos para a análise de texto completo. Após avaliação detalhada, foram excluídos todos os estudos porque não havia... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Coarctation of the aorta (CoA) accounts for 5% to 7% of congenital heart disease, with an incidence of 0.3 to 0.4 per 1000 live births. Surgery was the only choice of therapy for CoA until 1982 when balloon angioplasty became an available alternative for its treatment. Re-coarctation, aneurysm and aortic dissection remain the disadvantages of both treatments. To avoid those disadvantages, in 1990 endovascular stents were introduced for native coarctation and re-coarctation and since then they have become an alternative approach to surgical repair. The best approach to treat the CoA, whether open surgery or by stent placement, is not clear. To analyze the effectiveness and safety of stent placement compared with open surgery in patients with coarctation of the thoracic aorta. The Cochrane Peripheral Vascular Diseases Group searched their Specialised Register (last searched September 2011) and CENTRAL (2011, Issue 3).We also searched MEDLINE, EMBASE, CINAHL, AMED, Web of Science and LILACS (last searched in September 2011). We evaluated the located references and applied the inclusion criteria to selected studies. There was no restriction on language. Randomized or quasi-randomized controlled clinical trials that compared patients with CoA undergoing open surgery or stent placement. The review authors independently assessed the studies identified for eligibility for inclusion. We excluded studies after a consensus meeting. All identified studies were screened and had the selection criteria applied to the title and abstract. In total, we selected five studies for full-text analysis. After detailed evaluation, we excluded all studies because there was no comparison between stent placement and open surgery. There is insufficient evidence with regards to the best treatment for coarctation of the thoracic aorta. This review... (Complete abstract click electronic access below) / Doutor

Made available in DSpace on 2014-06-11T19:35:12Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-10-18Bitstream added on 2014-06-13T19:45:14Z : No. of bitstreams: 1 000740488.pdf: 1738682 bytes, checksum: 833b5e62b7c76ae97194eca5a3b73543 (MD5) / O reparo cirúrgico aberto do aneurisma da aorta abdominal (AAA) é um procedimento com alta taxa de morbimortalidade, internação hospitalar prolongada e custo elevado. Neste cenário, os programas multimodais de aceleração da recuperação pós-operatória (PMARP) podem contribuir para a otimização dos cuidados ao paciente e diminuir a utilização de recursos financeiros, mantendo-se a qualidade e a segurança. O objetivo desta revisão sistemática foi avaliar a eficácia e a segurança destes programas no reparo cirúrgico eletivo do AAA. Realizou-se revisão sistemática de estudos clínicos envolvendo os PMARP no reparo cirúrgico do AAA, avaliando a eficácia e segurança, quando comparados com os cuidados perioperatórios convencionais. Estudos clínicos foram recuperados eletronicamente das bases de dados MEDLINE, EMBASE, LILACS, Cochrane Trials Register (CENTRAL), por meio de estratégia de busca com termos apropriados. Identificaram-se os estudos aleatorizados controlados e os não aleatorizados (série de casos). Formulários padronizados foram utlizados para extração de dados. A análise estatística dos estudos aleatorizados foi executada com o programa REVMAN 5.0.2 e para os estudos não aleatórios foi utilizado o StatsDirect. Foram recuperados 13 estudos de série de casos e um ensaio clínico aleatorizado controlado unicêntrico. No ensaio clínico aleatorizado e controlado verificou-se redução significativa no tempo de hospitalização com o PMARP. A metanálise proporcional de série de casos não resultou em nenhuma diferença significativa entre pacientes tratados pelo PMARP e o tratamento convencional. O PMARP em cirurgias eletivas de AAA reduz o tempo de internação hospitalar, sem aumento de mortalidade. Devido aos níveis baixos de evidências, existe a necessidade de realização de mais ensaios aleatórios controlados para gerar grau de recomendação mais sólido / The open surgical repair of abdominal aortic aneurysm (AAA) is a procedure with high morbidity and mortality rates, prolonged hospital stay and high cost. In this scenario, the multimodal program for accelerated postoperative recovery (MPAPR) can contribute to the optimization of patient care and reduce the use of financial resources, maintaining quality and safety. The aim of this systematic review was to evaluate the efficacy and safety of these programs in elective surgical repair of AAA. We conducted a systematic review of clinical studies involving MPAPR in the surgical repair of AAA, evaluating the efficacy and safety compared with conventional perioperative care. Clinical studies were retrieved electronically from MEDLINE, EMBASE, LILACS, Cochrane Trials Register (CENTRAL), through search strategy with the appropriate terms. Identified the randomized controlled trials and non-randomized (number of cases). Standardized forms were utilized for data extraction. Statistical analysis of randomized trials were performed with the program RevMan 5.0.2 and the non-randomized studies was used StatsDirect. Retrieved 13 studies were case series and a randomized controlled single-center. In randomized controlled clinical trial found a significant reduction in hospitalization time with MPAPR. The meta-proportional number of cases resulted in no significant difference between patients treated by MPAPR and conventional treatment. The MPAPR in elective AAA reduces length of hospital stay without increasing mortality. Due to the low levels of evidence, there is a need for more randomized controlled trials to generate any degree of recommendation

Orientador: Paulo do Nascimento Junior / Coorientador: Regina Paolicci El Dib / Banca: Yara Marconde Machado Castilia / Banca: Marcone Lima Sobreira / Banca: Luiz Marcelo Sá Malbouisson / Banca: Luís Vicente Garcia / Resumo: O reparo cirúrgico aberto do aneurisma da aorta abdominal (AAA) é um procedimento com alta taxa de morbimortalidade, internação hospitalar prolongada e custo elevado. Neste cenário, os programas multimodais de aceleração da recuperação pós-operatória (PMARP) podem contribuir para a otimização dos cuidados ao paciente e diminuir a utilização de recursos financeiros, mantendo-se a qualidade e a segurança. O objetivo desta revisão sistemática foi avaliar a eficácia e a segurança destes programas no reparo cirúrgico eletivo do AAA. Realizou-se revisão sistemática de estudos clínicos envolvendo os PMARP no reparo cirúrgico do AAA, avaliando a eficácia e segurança, quando comparados com os cuidados perioperatórios convencionais. Estudos clínicos foram recuperados eletronicamente das bases de dados MEDLINE, EMBASE, LILACS, Cochrane Trials Register (CENTRAL), por meio de estratégia de busca com termos apropriados. Identificaram-se os estudos aleatorizados controlados e os não aleatorizados (série de casos). Formulários padronizados foram utilizados para extração de dados. A análise estatística dos estudos aleatorizados foi executada com o programa REVMAN 5.0.2 e para os estudos não aleatórios foi utilizado o StatsDirect. Foram recuperados 13 estudos de série de casos e um ensaio clínico aleatorizado controlado unicêntrico. No ensaio clínico aleatorizado e controlado verificou-se redução significativa no tempo de hospitalização com o PMARP. A metanálise proporcional de série de casos não resultou em nenhuma diferença significativa entre pacientes tratados pelo PMARP e o tratamento convencional. O PMARP em cirurgias eletivas de AAA reduz o tempo de internação hospitalar, sem aumento de mortalidade. Devido aos níveis baixos de evidências, existe a necessidade de realização de mais ensaios aleatórios controlados para gerar grau de recomendação mais sólido / Abstract: The open surgical repair of abdominal aortic aneurysm (AAA) is a procedure with high morbidity and mortality rates, prolonged hospital stay and high cost. In this scenario, the multimodal program for accelerated postoperative recovery (MPAPR) can contribute to the optimization of patient care and reduce the use of financial resources, maintaining quality and safety. The aim of this systematic review was to evaluate the efficacy and safety of these programs in elective surgical repair of AAA. We conducted a systematic review of clinical studies involving MPAPR in the surgical repair of AAA, evaluating the efficacy and safety compared with conventional perioperative care. Clinical studies were retrieved electronically from MEDLINE, EMBASE, LILACS, Cochrane Trials Register (CENTRAL), through search strategy with the appropriate terms. Identified the randomized controlled trials and non-randomized (number of cases). Standardized forms were utilized for data extraction. Statistical analysis of randomized trials were performed with the program RevMan 5.0.2 and the non-randomized studies was used StatsDirect. Retrieved 13 studies were case series and a randomized controlled single-center. In randomized controlled clinical trial found a significant reduction in hospitalization time with MPAPR. The meta-proportional number of cases resulted in no significant difference between patients treated by MPAPR and conventional treatment. The MPAPR in elective AAA reduces length of hospital stay without increasing mortality. Due to the low levels of evidence, there is a need for more randomized controlled trials to generate any degree of recommendation / Doutor

O presente estudo avaliou próteses vasculares de pequeno calibre feitas de polidimetilsiloxano (PDMS) com reforço de poliéster implantadas em aorta de coelhos através de fluoroscopia. Os objetivos do estudo foram: (1) analisar tubo de PDMS com reforço de poliéster implantado em aorta de coelhos como possível material para prótese vascular, (2) avaliar a patência das próteses através de fluoroscopia, (3) avaliar a condição de implante cirúrgico; (4) avaliar o comportamento macroscópico biológico do implante e (5) analisar o modelo experimental proposto. Próteses vasculares de PDMS foram implantadas na aorta infrarrenal de 64 coelhos cedidos pelo biotério da Faculdade de Medicina da Univesidade de São Paulo. Os exames de fluoroscopia foram realizados em até 150 dias após implantação cirúrgica. As próteses de PDMS foram classificadas em ocluídas e patentes, sendo essas sub-classificadas em diferentes graus de estenose. O tempo de clampeamento da aorta foi aferido durante os procedimentos cirúrgicos. De maneira amostral peças foram encaminhadas para microscopia eletrônica para verificação de endotelização das próteses. As análises estatísticas foram feitas através de teste t-Studant, teste ANOVA e Kaplan-Meier. Dos 64 animais que receberam a prótese, trinta (46,88%) apresentaram boa evolução clínica, vinte e três (35,94%) morreram e onze (17,18%) apresentaram paraplegia de membros posteriores. A patência das próteses em 30 dias foi de 87% (±6,7), em 60 dias foi de 73% (±9,3), em 90 dias foi de 57% (±11) e em 120 dias foi de 48% (±12). Cinquenta por cento (oito) das próteses patente não apresentaram nenhum grau de estenose, 35,5% (seis) apresentaram cinquenta por cento ou menos de estenose e 12,5% (dois) apresentaram estenose entre cinquenta e setenta por cento. Nenhum animal apresentou estenose maior que 70%. O tempo médio de clampeamento da aorta foi de 52 minutos. Não houve diferença significante nem na associação entre tempo de clampeamento da aorta e a evolução clínica dos animais (p=0,67) nem na associação entre o tempo de clampeamento e a patência das próteses (t=1,35; p=0,18). As peças encaminhadas para microscopia apresentaram crescimento endotelial a partir do vaso nativo em direção à prótese de PDMS. Foi possível concluir com este estudo que o PDMS demonstrou-se um material adequado para futuras pesquisas no ramo de próteses vasculares e que o uso da fluoroscopia na avaliação dessas próteses foi de fundamental importância na determinação da patência dos implantes / The present study evaluated small caliber vascular prostheses made of polydimethylsiloxane (PDMS) with polyester reinforcement implanted in the aorta of rabbits by fluoroscopy. The study objectives were: (1) analyze PDMS tube with polyester reinforcement implanted in the aorta of rabbits as possible material for vascular prosthesis, (2) assess the patency of the prosthesis through fluoroscopy, (3) assess the condition of surgical implant (4) evaluate the macroscopic behavior of biological implant and (5) analyze the proposed experimental model. Vascular prostheses were implanted in PDMS infrarenal aorta of 64 rabbits assigned by the animal house of the Faculty of Medicine of the University of São Paulo. Fluoroscopic examinations were performed within 150 days after surgical implantation. The prosthesis of PDMS were classified into occluded and patents, these being sub-classified into different degrees of stenosis. The time of aortic clamping was measured during surgical procedures. Sample pieces were sent for electron microscopy to check endothelialization of prostheses. Statistical analyzes were performed using t-test Studant, ANOVA and Kaplan-Meier. Of the 64 animals that received the prosthesis, thirty (46.88%) showed clinical improvement, twenty-three (35.94%) died and eleven (17.18%) had paraplegia of hind limbs. The patency of the prosthesis in 30 days was 87% (± 6.7), at 60 days was 73% (± 9.3), at 90 days was 57% (± 11) and at 120 days was 48 % (± 12). Fifty percent (eight) of the prosthesis patent did not present any degree of stenosis, 35.5% (six) had fifty percent or less of stenosis and 12.5% (two) had stenosis between fifty and seventy percent. No animal showed stenosis greater than 70%. The mean aortic clamping was 52 minutes. There was no significant difference in the association between duration of aortic clamping and clinical evolution of animals (p = 0.67) nor the association between clamping time and patency of the prosthesis (t = 1.35, p = 0.18). The parts sent for microscopy showed endothelial growth from the native vessel toward the prosthesis PDMS. It can be concluded from this study that the PDMS proved to be a suitable material for future research in the field of vascular prostheses and the use of fluoroscopy in the evaluation of these prostheses was of fundamental importance in determining the patency of the implants

O presente estudo avaliou próteses vasculares de pequeno calibre feitas de polidimetilsiloxano (PDMS) com reforço de poliéster implantadas em aorta de coelhos através de fluoroscopia. Os objetivos do estudo foram: (1) analisar tubo de PDMS com reforço de poliéster implantado em aorta de coelhos como possível material para prótese vascular, (2) avaliar a patência das próteses através de fluoroscopia, (3) avaliar a condição de implante cirúrgico; (4) avaliar o comportamento macroscópico biológico do implante e (5) analisar o modelo experimental proposto. Próteses vasculares de PDMS foram implantadas na aorta infrarrenal de 64 coelhos cedidos pelo biotério da Faculdade de Medicina da Univesidade de São Paulo. Os exames de fluoroscopia foram realizados em até 150 dias após implantação cirúrgica. As próteses de PDMS foram classificadas em ocluídas e patentes, sendo essas sub-classificadas em diferentes graus de estenose. O tempo de clampeamento da aorta foi aferido durante os procedimentos cirúrgicos. De maneira amostral peças foram encaminhadas para microscopia eletrônica para verificação de endotelização das próteses. As análises estatísticas foram feitas através de teste t-Studant, teste ANOVA e Kaplan-Meier. Dos 64 animais que receberam a prótese, trinta (46,88%) apresentaram boa evolução clínica, vinte e três (35,94%) morreram e onze (17,18%) apresentaram paraplegia de membros posteriores. A patência das próteses em 30 dias foi de 87% (±6,7), em 60 dias foi de 73% (±9,3), em 90 dias foi de 57% (±11) e em 120 dias foi de 48% (±12). Cinquenta por cento (oito) das próteses patente não apresentaram nenhum grau de estenose, 35,5% (seis) apresentaram cinquenta por cento ou menos de estenose e 12,5% (dois) apresentaram estenose entre cinquenta e setenta por cento. Nenhum animal apresentou estenose maior que 70%. O tempo médio de clampeamento da aorta foi de 52 minutos. Não houve diferença significante nem na associação entre tempo de clampeamento da aorta e a evolução clínica dos animais (p=0,67) nem na associação entre o tempo de clampeamento e a patência das próteses (t=1,35; p=0,18). As peças encaminhadas para microscopia apresentaram crescimento endotelial a partir do vaso nativo em direção à prótese de PDMS. Foi possível concluir com este estudo que o PDMS demonstrou-se um material adequado para futuras pesquisas no ramo de próteses vasculares e que o uso da fluoroscopia na avaliação dessas próteses foi de fundamental importância na determinação da patência dos implantes / The present study evaluated small caliber vascular prostheses made of polydimethylsiloxane (PDMS) with polyester reinforcement implanted in the aorta of rabbits by fluoroscopy. The study objectives were: (1) analyze PDMS tube with polyester reinforcement implanted in the aorta of rabbits as possible material for vascular prosthesis, (2) assess the patency of the prosthesis through fluoroscopy, (3) assess the condition of surgical implant (4) evaluate the macroscopic behavior of biological implant and (5) analyze the proposed experimental model. Vascular prostheses were implanted in PDMS infrarenal aorta of 64 rabbits assigned by the animal house of the Faculty of Medicine of the University of São Paulo. Fluoroscopic examinations were performed within 150 days after surgical implantation. The prosthesis of PDMS were classified into occluded and patents, these being sub-classified into different degrees of stenosis. The time of aortic clamping was measured during surgical procedures. Sample pieces were sent for electron microscopy to check endothelialization of prostheses. Statistical analyzes were performed using t-test Studant, ANOVA and Kaplan-Meier. Of the 64 animals that received the prosthesis, thirty (46.88%) showed clinical improvement, twenty-three (35.94%) died and eleven (17.18%) had paraplegia of hind limbs. The patency of the prosthesis in 30 days was 87% (± 6.7), at 60 days was 73% (± 9.3), at 90 days was 57% (± 11) and at 120 days was 48 % (± 12). Fifty percent (eight) of the prosthesis patent did not present any degree of stenosis, 35.5% (six) had fifty percent or less of stenosis and 12.5% (two) had stenosis between fifty and seventy percent. No animal showed stenosis greater than 70%. The mean aortic clamping was 52 minutes. There was no significant difference in the association between duration of aortic clamping and clinical evolution of animals (p = 0.67) nor the association between clamping time and patency of the prosthesis (t = 1.35, p = 0.18). The parts sent for microscopy showed endothelial growth from the native vessel toward the prosthesis PDMS. It can be concluded from this study that the PDMS proved to be a suitable material for future research in the field of vascular prostheses and the use of fluoroscopy in the evaluation of these prostheses was of fundamental importance in determining the patency of the implants