Tratamento endovascular dos aneurismas da aorta abdominal com anatomia complexa: resultados preliminares com a segunda geração de endoprótese com arcabouço metálico circular

INTRODUÇÃO: O tratamento endovascular dos aneurismas da aorta abdominal tem revolucionado o tratamento dessa afecção, em decorrência das baixas taxas de morbidade e mortalidade. Apesar dos avanços tecnológicos ocorridos nas endopróteses, ainda existem limitações anatômicas para o emprego da técnica. Este estudo teve por objetivo avaliar os resultados imediatos do tratamento de pacientes portadores de aneurisma da aorta abdominal com anatomia complexa com uma endoprótese de segunda geração. MÉTODOS: Estudo observacional, prospectivo, não-randomizado, realizado em um único centro, em uma série de pacientes submetidos a tratamento endovascular de aneurismas da aorta abdominal infrarrenais complexos, com prótese com arcabouço metálico disposta em anéis (Anaconda - Vascutek, Terumo, Inchinnan, Escócia). Foram avaliados as características clínicas e angiográficas, o sucesso técnico, o sucesso terapêutico, a morbidade e a mortalidade, e a taxa de reintervenção perioperatória. RESULTADOS: Foram analisados, no período de fevereiro de 2010 a dezembro de 2011, 108 pacientes consecutivos portadores de aneurisma da aorta, dos quais 16 eram portadores de aneurisma da aorta abdominal com anatomia complexa tratados com a prótese Anaconda . A média de idade foi de 76 + 7 anos e 75% eram do sexo masculino. Houve sucesso técnico em 94% e êxito terapêutico em 75% dos casos. Ocorreu um óbito no pós-operatório. As complicações perioperatórias mais prevalentes foram sangramento da ferida operatória (2/16) e embolia periférica (2/16). Foram necessárias reintervenções em 12,5% dos pacientes durante o seguimento. CONCLUSÕES: Neste estudo, a segunda geração da endoprótese Anaconda foi efetiva e apresenta resultados imediatos satisfatórios no tratamento do aneurisma da aorta abdominal infrarrenal de anatomia complexa.

Mechanical simulation of the endovascular repair of abdominal aortic aneurysms

Ce travail de thèse porte sur la simulation du déploiement des prothèses vasculaires de type stent-graft (SG) lors de la réparation endovasculaire (EVAR) des anévrismes de l’aorte abdominale (AAA). Cette étude se présente en trois parties: (i) tests mécaniques en flexion et compression de SG couramment utilisés (corps et jambage de marque Cook) ainsi que la simulation numérique desdits tests, (ii) développement d’un modèle numérique d’anévrisme, (iii) stratégie de simulation du déploiement des SG. La méthode numérique employée est celle des éléments finis. Dans un premier temps, une vérification du modèle éléments finis (MEF) des SG est realisée par comparaison des différents cas de charge avec leur pendant expérimental. Ensuite, le MEF vasculaire (AAA) est lui aussi vérifié lors d’une comparaison des niveaux de contraintes maximales principales dans la paroi avec des valeurs de la littérature. Enfin, le déploiement est abordé tout en intégrant les cathéters. Les tests mécaniques menés sur les SG ont été simulés avec une différence maximale de 5,93%, tout en tenant compte de la pré-charge des stents. Le MEF de la structure vasculaire a montré des contraintes maximales principales éloignées de 4,41% par rapport à un modèle similaire précédemment publié. Quant à la simulation du déploiement, un jeu complet de SG a pu être déployé avec un bon contrôle de la position relative et globale, dans un AAA spécifique pré-déformé, sans toutefois inclure de thrombus intra-luminal (TIL). La paroi du AAA a été modélisée avec une loi de comportement isotropique hyperélastique. Étant donné que la différence maximale tolérée en milieu clinique entre réalité et simulation est de 5%, notre approche semble acceptable et pourrait donner suite à de futurs développements. Cela dit, le petit nombre de SG testés justifie pleinement une vaste campagne de tests mécaniques et simulations supplémentaires à des fins de validation.

Análise morfométrica da parede arterial após o implante de stent em aorta abdominal de suínos : estudo comparativo entre stents metálicos não recobertos e recobertos com politetrafluoroetileno

O espessamento intimal e a reestenose que ocorrem após os procedimentos de angioplastia transluminal percutânea e/ou o implante de stents representam uma causa freqüente de falência destes procedimentos. O principal achado patológico responsável pela reestenose parece ser a hiperplasia intimal, já que o dispositivo intravascular é resistente ao remodelamento arterial geométrico. O propósito deste estudo é avaliar, através da morfometria digital, o espessamento intimal presente nas regiões da parede arterial imediatamente proximal e distal ao implante de um stent metálico em configuração em “Z “ não recoberto ou recoberto com PTFE. Vinte e cinco suínos de raça mista, com seis a dez semanas de idade, pesando em média 20 kg foram divididos em três grupos. No grupo I, cinco animais foram submetidos à exposição cirúrgica retroperitoneal da aorta abdominal, aortotomia e manipulação com uma bainha introdutora de 12 F. O grupo II incluiu dez animais que foram submetidos ao implante de um stent metálico auto-expansível não recoberto. No grupo III, incluindo também dez animais, foram implantados stents recobertos com PTFE. Após quatro semanas, todos os animais foram sacrificados e o segmento aorto-ilíaco foi removido. Quatro animais foram excluídos do estudo por trombose da aorta (um animal do grupo II e três animais do grupo III). Para a análise morfométrica foram utilizados os testes não paramétricos de Wilcoxon e de Kruskal-Wallis, para as comparações, respectivamente, no mesmo grupo e entre os grupos. Foi adotado o nível de significância de 5% ( p< 0,05). Quando os espécimes da parede arterial, imediatamente proximal e distal aos stents foram comparados, nenhuma diferença estatisticamente significativa foi encontrada entre as áreas luminal, intimal, média ou índice intimal em cada grupo. Na comparação entre os grupos, as áreas intimal, média e o índice intimal não demonstraram variação estatisticamente significativa. Foram identificadas diferenças entre os grupos quanto às áreas luminais proximais (p = 0,036) e distais (p=0,044). Pelo teste de comparações múltiplas para Kruskal-Wallis (Teste de Dunn) identificou-se diferença significativa entre os grupos I e II. Entretanto, quando estas variáveis foram controladas pelo fator peso (relação área luminal/peso) a diferença não foi mais observada. Concluímos que, após quatro semanas, stents recobertos com PTFE induzem um espessamento intimal justa-stent similar ao observado com stents não recobertos ou com a simples manipulação arterial com uma bainha introdutora. Neste modelo experimental suíno, de curto seguimento, o revestimento com PTFE não foi responsável por adicional espessamento intimal.

Endovascular repair of a juxtarenal saccular aneurysm using the Multilayer Flow Modulator: report of the first case performed in a Public Hospital in Brazil

Endovascular aortic aneurysm repair (EVAR) involving renal and visceral arteries remains a great challenge. Several techniques have been developed over the time to treat juxtarenal, pararenal and thoracoabdominal aneurysms, highlighting the fenestrated and branched endografts, parallel prostheses as Chimney, Periscope and Sandwich Techniques and the use of flow modulation by multilayer stent. We report a case of saccular juxtarenal aortic aneurysm with high surgical risk for complex airway access due to a history of radical laryngectomy for laryngeal neoplasm. Due to chronic aorto-iliac obstructive disease, ostial stenosis of renal artery and limited diameter of the suprarenal aorta, we discarded options involving fenestrated/branched endografts and involving parallel prostheses techniques. We present this case as a therapeutic challenge and a successful treatment option in the short-term evaluation.

Huge aneurysm of the ascending aorta in a patient with adult-type Pompe's disease: histological findings mimicking fibrillinopathy

Adult-type Pompe's disease (glycogen storage disease type II) has rarely been shown to present with dilatative arteriopathy, suggesting potential smooth muscle involvement in addition to lysosomal glycogen deposits usually restricted to skeletal muscle tissue. We report the case of a middle-aged man under enzyme replacement therapy presenting with an exceedingly large thoracic aortic aneurysm. Surprisingly, the histological work-up of resected aortic tissue revealed changes mimicking those observed in patients with classic connective tissue diseases. Enzyme replacement therapy, in addition to musculoskeletal and pulmonary treatment for patients with Pompe's disease, may prolong survival and lead to patients presenting with vascular alterations that may pose surgical and potential diagnostic challenges in the future.

Statins are associated with decreased mortality in abdominal, but not in thoracic aortic aneurysm patients undergoing endovascular repair: propensity score-adjusted analysis

BACKGROUND: Purpose of this study was to compare the correlation of statin use with long-term mortality in patients with abdominal (AAA) and thoracic aortic aneurysm (TAA). PATIENTS AND METHODS: We compared long-term survival of 731 AAA and 59 TAA patients undergoing elective endovascular repair (EVAR). Kaplan-Meier survival curves were compared by the log-rank method. Propensity score-adjusted multivariable logistic regression models were used to determine independent associations of statin use on vital status after EVAR. RESULTS: Statin use was associated with decreased long-term mortality in AAA patients in bivariate and multivariable regression analysis, in which the effect of propensity to receive a statin was considered (adjusted HR: .613, 95%-CI: .379- .993, p = .047) whereas mortality of TAA patients was not associated with use of statins (adjusted HR: 1.795, 95%-CI: .147 -21.942, p = .647). CONCLUSIONS: Use of statins is an independent predictor of decreased mortality after elective EVAR in AAA, but not in TAA patients. These findings indirectly support the concept of a distinct pathogenesis of AAA and TAA.

Quantitative evaluation of patient-specific conforming hexahedral meshes of abdominal aortic aneurysms and intraluminal thrombus generated from MRI

A novel method for generating patient-specific high quality conforming hexahedral meshes is presented. The meshes are directly obtained from the segmentation of patient magnetic resonance (MR) images of abdominal aortic aneu-rysms (AAA). The MRI permits distinguishing between struc-tures of interest in soft tissue. Being so, the contours of the lumen, the aortic wall and the intraluminal thrombus (ILT) are available and thus the meshes represent the actual anato-my of the patient?s aneurysm, including the layered morpholo-gies of these structures. Most AAAs are located in the lower part of the aorta and the upper section of the iliac arteries, where the inherent tortuosity of the anatomy and the presence of the ILT makes the generation of high-quality elements at the bifurcation is a challenging task. In this work we propose a novel approach for building quadrilateral meshes for each surface of the sectioned geometry, and generating conforming hexahedral meshes by combining the quadrilateral meshes. Conforming hexahedral meshes are created for the wall and the ILT. The resulting elements are evaluated on four patients? datasets using the Scaled Jacobian metric. Hexahedral meshes of 25,000 elements with 94.8% of elements well-suited for FE analysis are generated.

Cirugía Abierta Versus Cirugía Endovascular en el Tratamiento de la Patología de la Aorta Torácica Descendente

El reparo endovascular de la aorta torácica (REVAT), se ha incrementado en el mundo en los últimos años con relación al abierto. Los resultados de la intervención son controversiales. La información en Colombia es insuficiente. Objetivo: Comparar los resultados clínicos del REVAT frente al reparo abierto en la Fundación Cardio Infantil (Bogotá, Col) entre 2002 y 2011. Metodología: Análisis retrospectivo de la cohorte de pacientes sometidos a reparo abierto (Grupo 1) en comparación de REVAT (grupo 2). En cada uno de los grupos se evaluó el tiempo quirúrgico, tasa de morbilidad (infección, hemo-rragia, isquemia medular, evento cerebrovascular [ECV] y falla renal postoperatoria), mortalidad, reintervención y estancia hospitalaria. Para las comparaciones se realizó un análisis univariado considerando un valor p<0.05 estadísticamente significativo. Resultados: Fueron incluidos 57 pacientes en el análisis (26% reparo abierto; 74% REVAT). Se reintervinieron 2 pacientes por endofugas tipo 1 en el Grupo 2 y un caso por sangrado en el Grupo 1. La mortalidad operatoria fue (Grupo1: 20%; Grupo 2: 2.3%). El tiempo quirúrgico fue de 398 ± 180 min Grupo 1 versus 85.5 ± 35 min en el Grupo 2 (p:0.0001) y el tiempo de estancia hospitalaria promedio fue de 9.8 días:Grupo 1 y 5,3 días Grupo 2 [p:0.01]). El tiempo promedio de seguimiento fue 4,8± 3,1 años. Conclusiones: El REVAT parece ofrecer menor morbilidad, mortalidad, tiempo quirúrgico y estancia hospitalaria respecto al reparo abierto, aunque las pobla-ciones de pacientes incluidos no fueron estrictamente comparables. Se requieren nuevos análisis en un diseño prospectivo, idealmente aleatorizado para documentar los beneficios a largo plazo de este tipo de reparo.

Modified 'Stent-Graft Sandwich' Technique for Treatment of Isolated Common Iliac Artery Aneurysm in Patient With Marfan Syndrome

Isolated iliac artery aneurysms are rare in the general population (0.03%) and represent 2% of all abdominal aneurysms, and the association with Marfan syndrome is even rarer. We report a Marfan syndrome case with an isolated common iliac artery aneurysm treated by using a modified 'stent-graft sandwich' technique, with preservation of the internal iliac artery perfusion. The modified 'stent-graft sandwich' technique involves building an appropriate proximal neck just in the common iliac artery for fittingly housing two new stent-grafts inside, both deployed simultaneously and each one going to both distal iliac arteries (internal and external).

Collagen is reduced and disrupted in human aneurysms and dissections of ascending aorta

In ascending aorta aneurysms, there is an enlargement of the whole vessel, whereas aortic dissections (ADs) are characterized by the cleavage of the wall into 2 sheets at the external half. We searched if alterations in collagen could be related to these diseases. Sections of aortas from 14 case patients with acute dissections, 10 case patients with aneurysms, and 9 control subjects were stained with picrosirius. Slides were analyzed under polarized microscopy to evaluate the structure of collagen fibers. The proportion of collagen was calculated in each half of the medial layer by color detection in a computerized image analysis system. Collagen appearance under polarized light was consistent with collagenolysis. The mean collagen proportions at the inner and outer halves, respectively, were 0.50 +/- 0.13 and 0.40 +/- 0.08 in the control group, 0.20 +/- 0.10 and 0.18 +/- 0.12 in the AD group, and 0.33 +/- 0.12 and 0.19 +/- 0.12 in the aneurysm group. The AD (P < .01) and control (P = .04) groups had less collagen at the external half, no difference was found in the aneurysm group (P = .71). In both halves, there was less collagen in the case patients than in the control subjects (all P < .01), but at the internal half, the decrease was significantly greater in the case patients with aneurysms than in those with dissections (P = .03; at the external half, P = .99). Aortic dissections and aneurysms show a decrease in collagen content that could be related to a weakness of the wall underlying the diseases, but the locations of the decrease differ: in dissections, it is situated mostly at the external portion of the media (site of cleavage), whereas in aneurysms, it is more diffuse, consistent with the global enlargement. (c) 2008 Elsevier B.V. All rights reserved.

Endovascular treatment of pseudoaneurysm of the thoracic aorta from a firearm injury

A 24-year-old male patient was the victim of a firearm wound that penetrated the thorax. He arrived at another hospital hemodynamically unstable and was submitted to exploratory surgery by means of bithoracotomy. A lesion of the left branch of the pulmonary artery was detected and successfully repaired. He was submitted for computer-aided tomography on the fifth postoperative day, and a lesion of the mid-thoracic aorta was detected, which formed a saccular image. Considering that the patient had already been submitted to a bithoracotomy and that a direct approach to repair would involve another thoracotomy within a short period of time, endovascular treatment was chosen in our hospital. The procedure was performed under fluoroscopy. A second computer-aided tomography indicated adequate treatment of the lesion, with no indication of an endoleak. He has undergone ambulatory follow-up for 36 months without any problem related to the procedure. While endovascular treatment of the aorta has developed enormously, multicenter studies are needed to better define the long-term results of this approach. © 2008 Published by European Association for Cardio-Thoracic Surgery. All rights reserved.

Arquitetura da parede vascular de segmentos torácico e abdominais da aorta de macaco prego (Cebus apella)

The intimal layer of the thoracic and abdominal aortic segments of Cebus apella monkey presented an evident inner elastic lamina. The medial layer of the thoracic aorta segment showed a basic lamellar elastic pattern having a medium average of 23.12 lamellae per analyzed cut sections, which appeared disposed circular and oblique relatively to the aortic lumen. The aortic adventitial layer, at this level, was formed mainly by collagen fibers, irregularly disposed between elastic fibers and smooth muscle cells. The aortic abdominal portion, in this monkey, at the suprarenal level presented a medium number of 19.12 elastic lamellae which showed a relatively disorganized and broken up pattern. At the infrarenal level the aortic medium layer showed a medium average of 11.75 elastic lamellae and next to the emission of the internal iliac arteries it was found only a middle average of 8.37 elastic lamellae intermingled with smooth muscle cells and collagen fibers whose concentration seemed to be increased next to the adventitial layer. The external elastic lamina was only present in the more distal aortic segment near to the emission of the internal iliac arteries.

Colocação de endoprótese vascular versus cirurgia para coarctação de aorta: revisão sistemática

Pós-graduação em Bases Gerais da Cirurgia - FMB

Trends in aortic aneurysm- and dissection-related mortality in the state of Sao Paulo, Brazil, 1985-2009: multiple-cause-of-death analysis

Background: Aortic aneurysm and dissection are important causes of death in older people. Ruptured aneurysms show catastrophic fatality rates reaching near 80%. Few population-based mortality studies have been published in the world and none in Brazil. The objective of the present study was to use multiple-cause-of-death methodology in the analysis of mortality trends related to aortic aneurysm and dissection in the state of Sao Paulo, between 1985 and 2009. Methods: We analyzed mortality data from the Sao Paulo State Data Analysis System, selecting all death certificates on which aortic aneurysm and dissection were listed as a cause-of-death. The variables sex, age, season of the year, and underlying, associated or total mentions of causes of death were studied using standardized mortality rates, proportions and historical trends. Statistical analyses were performed by chi-square goodness-of-fit and H Kruskal-Wallis tests, and variance analysis. The joinpoint regression model was used to evaluate changes in age-standardized rates trends. A p value less than 0.05 was regarded as significant. Results: Over a 25-year period, there were 42,615 deaths related to aortic aneurysm and dissection, of which 36,088 (84.7%) were identified as underlying cause and 6,527 (15.3%) as an associated cause-of-death. Dissection and ruptured aneurysms were considered as an underlying cause of death in 93% of the deaths. For the entire period, a significant increased trend of age-standardized death rates was observed in men and women, while certain non-significant decreases occurred from 1996/2004 until 2009. Abdominal aortic aneurysms and aortic dissections prevailed among men and aortic dissections and aortic aneurysms of unspecified site among women. In 1985 and 2009 death rates ratios of men to women were respectively 2.86 and 2.19, corresponding to a difference decrease between rates of 23.4%. For aortic dissection, ruptured and non-ruptured aneurysms, the overall mean ages at death were, respectively, 63.2, 68.4 and 71.6 years; while, as the underlying cause, the main associated causes of death were as follows: hemorrhages (in 43.8%/40.5%/13.9%); hypertensive diseases (in 49.2%/22.43%/24.5%) and atherosclerosis (in 14.8%/25.5%/15.3%); and, as associated causes, their principal overall underlying causes of death were diseases of the circulatory (55.7%), and respiratory (13.8%) systems and neoplasms (7.8%). A significant seasonal variation, with highest frequency in winter, occurred in deaths identified as underlying cause for aortic dissection, ruptured and non-ruptured aneurysms. Conclusions: This study introduces the methodology of multiple-causes-of-death to enhance epidemiologic knowledge of aortic aneurysm and dissection in Sao Paulo, Brazil. The results presented confer light to the importance of mortality statistics and the need for epidemiologic studies to understand unique trends in our own population.

Trends in aortic aneurysm- and dissection-related mortality in the state of São Paulo, Brazil, 1985–2009: multiple-cause-of-death analysis

Background: Aortic aneurysm and dissection are important causes of death in older people. Ruptured aneurysms show catastrophic fatality rates reaching near 80%. Few population-based mortality studies have been published in the world and none in Brazil. The objective of the present study was to use multiple-cause-of-death methodology in the analysis of mortality trends related to aortic aneurysm and dissection in the state of Sao Paulo, between 1985 and 2009. Methods: We analyzed mortality data from the Sao Paulo State Data Analysis System, selecting all death certificates on which aortic aneurysm and dissection were listed as a cause-of-death. The variables sex, age, season of the year, and underlying, associated or total mentions of causes of death were studied using standardized mortality rates, proportions and historical trends. Statistical analyses were performed by chi-square goodness-of-fit and H Kruskal-Wallis tests, and variance analysis. The joinpoint regression model was used to evaluate changes in age-standardized rates trends. A p value less than 0.05 was regarded as significant. Results: Over a 25-year period, there were 42,615 deaths related to aortic aneurysm and dissection, of which 36,088 (84.7%) were identified as underlying cause and 6,527 (15.3%) as an associated cause-of-death. Dissection and ruptured aneurysms were considered as an underlying cause of death in 93% of the deaths. For the entire period, a significant increased trend of age-standardized death rates was observed in men and women, while certain non-significant decreases occurred from 1996/2004 until 2009. Abdominal aortic aneurysms and aortic dissections prevailed among men and aortic dissections and aortic aneurysms of unspecified site among women. In 1985 and 2009 death rates ratios of men to women were respectively 2.86 and 2.19, corresponding to a difference decrease between rates of 23.4%. For aortic dissection, ruptured and non-ruptured aneurysms, the overall mean ages at death were, respectively, 63.2, 68.4 and 71.6 years; while, as the underlying cause, the main associated causes of death were as follows: hemorrhages (in 43.8%/40.5%/13.9%); hypertensive diseases (in 49.2%/22.43%/24.5%) and atherosclerosis (in 14.8%/25.5%/15.3%); and, as associated causes, their principal overall underlying causes of death were diseases of the circulatory (55.7%), and respiratory (13.8%) systems and neoplasms (7.8%). A significant seasonal variation, with highest frequency in winter, occurred in deaths identified as underlying cause for aortic dissection, ruptured and non-ruptured aneurysms. Conclusions: This study introduces the methodology of multiple-causes-of-death to enhance epidemiologic knowledge of aortic aneurysm and dissection in São Paulo, Brazil. The results presented confer light to the importance of mortality statistics and the need for epidemiologic studies to understand unique trends in our own population.