RESUMO
BACKGROUND: Accurate diagnosis and treatment of complex cardiac tumors poses challenges, particularly when surgical resection is considered. 3D reconstruction and printing appear as a novel approach to allow heart teams for optimal surgical and post operative care. METHODS: We report two patients with uncommon masses including a cardiac angiosarcoma (CAS) and a IgG4-related disease (IgG4-RD) with exclusive cardiac involvement. In both cases, three-dimensional (3D) reconstruction and 3D-printed models were utilized to aid the surgical team achieve optimal pre-operative planning. Both patients underwent ECG-gated cardiac computed tomography angiography (CCTA) imaging and, due to the complex anatomy of the masses, their large dimensions, proximity to vital cardiac and vascular structures, and unclear etiology, computational and 3D-printed models were created for surgical planning. An exploratory literature review of studies using 3D-printed models in surgical planning was performed. RESULTS: In case 1 (CAS), due to the size and extension of the mass to the right ventricular free wall, surgical intervention was not considered curative and, during thoracotomy, an open biopsy confirmed the imaging suspicion of CAS which guided the initiation of optimal medical treatment with chemotherapy and, after clear tumor retraction, the patient underwent a second surgical intervention, and during the 18 months of follow-up showed no signs of recurrence. In Case 2 (IgG4-RD), the patient underwent uncomplicated total surgical resection; this allowed directed treatment and, at 12 months follow-up, there are no signs of recurrence. Computational and 3D-printed models were used to plan the surgery and to confirm the findings. Limited studies have explored the use of 3D printing in the surgical planning of tumors. CONCLUSIONS: We present two patients with uncommon cardiac tumors, highlighting the significant value of 3D models in the anatomical characterization and assessment of their extension. These models may be essential in surgical planning for complex cardiovascular cases and could provide more information than conventional imaging modalities. Further studies are needed to demonstrate the impact of 3D technologies in studying cardiac tumors.
Assuntos
Neoplasias Cardíacas , Hemangiossarcoma , Impressão Tridimensional , Humanos , Neoplasias Cardíacas/cirurgia , Neoplasias Cardíacas/diagnóstico por imagem , Masculino , Hemangiossarcoma/cirurgia , Hemangiossarcoma/diagnóstico por imagem , Pessoa de Meia-Idade , Imageamento Tridimensional , Feminino , Idoso , Procedimentos Cirúrgicos Cardíacos/métodos , Angiografia por Tomografia ComputadorizadaRESUMO
Vascular grafts (VGs) are medical devices intended to replace the function of a blood vessel. Available VGs in the market present low patency rates for small diameter applications setting the VG failure. This event arises from the inadequate response of the cells interacting with the biomaterial in the context of operative conditions generating chronic inflammation and a lack of regenerative signals where stenosis or aneurysms can occur. Tissue Engineered Vascular grafts (TEVGs) aim to induce the regeneration of the native vessel to overcome these limitations. Besides the biochemical stimuli, the biomaterial and the particular micro and macrostructure of the graft will determine the specific behavior under pulsatile pressure. The TEVG must support blood flow withstanding the exerted pressure, allowing the proper compliance required for the biomechanical stimulation needed for regeneration. Although the international standards outline the specific requirements to evaluate vascular grafts, the challenge remains in choosing the proper biomaterial and manufacturing TEVGs with good quality features to perform satisfactorily. In this review, we aim to recognize the best strategies to reach suitable mechanical properties in cell-free TEVGs according to the reported success of different approaches in clinical trials and pre-clinical trials.
RESUMO
Despite the wide variety of tissue-engineered vascular grafts that are currently being developed, autologous vessels, such as the saphenous vein, are still the gold standard grafts for surgical treatment of vascular disease. Recently developed technologies have shown promising results in preclinical studies, but they still do not overcome the issues that native vessels present, and only a few have made the transition into clinical use. The endothelial lining is a key aspect for the success or failure of the grafts, especially on smaller diameter grafts (<5 mm). However, during the design and evaluation of the grafts, the mechanisms for the formation of this layer are not commonly examined. Therefore, a significant amount of established research might not be relevant to the clinical context, due to important differences that exist between the vascular regeneration mechanisms found in animal models and humans. This article reviews current knowledge about endothelialization mechanisms that have been so far identified: in vitro seeding, transanastomotic growth, transmural infiltration, and fallout endothelialization. Emphasis is placed on the models used for study of theses mechanisms and their effects on the development of tissue-engineering vascular conduits.
Assuntos
Prótese Vascular , Células Endoteliais/metabolismo , Endotélio Vascular/metabolismo , Neovascularização Fisiológica , Doenças Vasculares/terapia , Remodelação Vascular , Animais , Humanos , Modelos AnimaisRESUMO
In Bi-directional Glenn (BDG) physiology, the superior systemic circulation and pulmonary circulation are in series. Consequently, only blood from the superior vena cava is oxygenated in the lungs. Oxygenated blood then travels to the ventricle where it is mixed with blood returning from the lower body. Therefore, incremental changes in oxygen extraction ratio (OER) could compromise exercise tolerance. In this study, the effect of exercise on the hemodynamic and ventricular performance of BDG physiology was investigated using clinical patient data as inputs for a lumped parameter model coupled with oxygenation equations. Changes in cardiac index, Qp/Qs, systemic pressure, oxygen extraction ratio and ventricular/vascular coupling ratio were calculated for three different exercise levels. The patient cohort (n=29) was sub-grouped by age and pulmonary vascular resistance (PVR) at rest. It was observed that the changes in exercise tolerance are significant in both comparisons, but most significant when sub-grouped by PVR at rest. Results showed that patients over 2 years old with high PVR are above or close to the upper tolerable limit of OER (0.32) at baseline. Patients with high PVR at rest had very poor exercise tolerance while patients with low PVR at rest could tolerate low exercise conditions. In general, ventricular function of SV patients is too poor to increase CI and fulfill exercise requirements. The presented mathematical model provides a framework to estimate the hemodynamic performance of BDG patients at different exercise levels according to patient specific data.
Assuntos
Exercício Físico/fisiologia , Hemodinâmica , Oxigênio/metabolismo , Circulação Pulmonar/fisiologia , Função Ventricular/fisiologia , Criança , Pré-Escolar , Tolerância ao Exercício/fisiologia , Cardiopatias Congênitas/fisiopatologia , Ventrículos do Coração/fisiopatologia , Humanos , Lactente , Recém-Nascido , Descanso/fisiologia , Resistência Vascular/fisiologia , Veia Cava Superior/fisiopatologiaRESUMO
The considerable blood mixing in the bidirectional Glenn (BDG) physiology further limits the capacity of the single working ventricle to pump enough oxygenated blood to the circulatory system. This condition is exacerbated under severe conditions such as physical activity or high altitude. In this study, the effect of high altitude exposure on hemodynamics and ventricular function of the BDG physiology is investigated. For this purpose, a mathematical approach based on a lumped parameter model was developed to model the BDG circulation. Catheterization data from 39 BDG patients at stabilized oxygen conditions was used to determine baseline flows and pressures for the model. The effect of high altitude exposure was modeled by increasing the pulmonary vascular resistance (PVR) and heart rate (HR) in increments up to 80% and 40%, respectively. The resulting differences in vascular flows, pressures and ventricular function parameters were analyzed. By simultaneously increasing PVR and HR, significant changes (p <0.05) were observed in cardiac index (11% increase at an 80% PVR and 40% HR increase) and pulmonary flow (26% decrease at an 80% PVR and 40% HR increase). Significant increase in mean systemic pressure (9%) was observed at 80% PVR (40% HR) increase. The results show that the poor ventricular function fails to overcome the increased preload and implied low oxygenation in BDG patients at higher altitudes, especially for those with high baseline PVRs. The presented mathematical model provides a framework to estimate the hemodynamic performance of BDG patients at different PVR increments.
Assuntos
Altitude , Cardiopatias Congênitas/fisiopatologia , Frequência Cardíaca , Resistência Vascular/fisiologia , Cateterismo Cardíaco , Pré-Escolar , Estudos de Coortes , Técnica de Fontan/métodos , Ventrículos do Coração/fisiopatologia , Hemodinâmica , Humanos , Lactente , Modelos Cardiovasculares , Oxigênio/químicaRESUMO
Objetivo: Evaluar el efecto de la reanimación con lactato de Ringer sobre variables hemodinámicas sistémicas e intestinales en conejos sometidos a shock hemorrágico. Metodología: Se condujo un experimento animal no controlado. Se sometieron 10 conejos Nueva Zelanda a un procedimiento consistente en canalización de arteria de la oreja y de vena femoral, con posterior laparotomía y toracotomía para colocación de transductores de flujo en la base de la aorta y en arteria mesentérica superior. Se indujo hemorragia profunda de 28 mL/kg y posteriormente se hizo reanimación con Lactato de Ringer en relación de 3:1 de volumen perdido. Durante la hemorragia y la reanimación se midieron presión arterial media, fredcuencia cardiaca, gasto cardiaco (índice cardiaco), flujo sanguíneo esplácnico (índice esplácnico) y tasa de flujo intestinal-sistémica (TFIS). Resultados: La presión arterial media disminuyó durante la hemorragia, con recuperación parcial con la reanimación de líquidos. La frecuencia cardiaca aumentó con hemorragia y se estabilizó con la reanimación sin alcanzar los niveles basales. El índice cardiaco y el índice esplácnico disminuyeron significativamente durante la hemorragia y se recuperaron solo de manera parcial durante la reanimación. Sin embargo, la recuperación con respecto a valores basales del índice esplácnico (66%) fue menor que el del índice cardiaco (90%, lo cual es consistente con el comportamiento del TFIS. Conclusiones: La reanimación con Lactato de Ringer es insuficiente para restaurar la circulación esplácnica en mayor medida que para restablecer el índice cardiaco. Es posible que sea recomendable adicionar estrategias terapéuticas adicionales a la reanimación con líquidos para limitar la hipoperfusión intestinal durante shock hemorrágico.
Objective: To evaluate the effect of fluid resuscitation with lactated Ringer's solution on intestinal and systemic hemodynamic variables during hemorrhagic shock in rabbits. Methods: A controlled animal trial was conducted. Ten New Zealand rabbits underwent ear artery and femoral vein cannulation and thoraco-laparotomy in order to place flow transducers around the aortic root and superior mesenteric artery. Hemorrhage was induces up to 28 mL/kg, and then fluid resuscitation with lactated Ringer's solution was performed in a ratio 3:1 to blood loss. During hemorrhagic and resuscitation periods, mean arterial pressure, heart rate, cardiac output (cardiac index), splanchnic blood flow (splanchnic index) and intestinal to systemic flow ratio (TFIS) were measured. Results: Mean arterial pressure decreased during hemorrhage, with partial recovery during fluid resuscitation. Heart rate increased during hemorrhage and got stable during resuscitation not reaching baseline levels. On the other hand, cardiac index and splanchnic index decreased significantly during hemorrhage as well as during resuscitation. However, splanchnic index restoration with respect to baseline (66%) was significantly lower tan cardiac index restoration during fluid resuscitation, which is consistent with TFIS behavior. Conclusions: Fluid resuscitation with lactated Ringer's solution is less able to completely restore splanchnic flow as compared to systemic flow. It would be a useful recommendation to add different therapeutic strategies to fluid resuscitation to limit gut hypoperfusion during hemorrhagic shock.
Assuntos
Animais , Baço , Choque , Débito Cardíaco , Hemorragia , Reanimação Cardiopulmonar , AnimaisRESUMO
Introducción: teniendo en cuenta el envejecimiento progresivo de la población y la alta prevalencia reportada de las lesiones del manguito rotador en ese grupo etario, no es de extrañar que esta patología se convierta en un problema de salud pública. Se sabe que el aumento en el tamaño de una lesión se asocia con la aparición de síntomas, pero no existen herramientas que permitan predecir la evolución del tamaño de una lesión. Con esto en mente, se desarrolló una línea de investigación para estudiar el mecanismo de falla que inicia con la realización de un modelo tridimensional del tendón del músculo supraespinoso sano. Materiales y métodos: se caracterizó el tendón del músculo supraespinoso aplicando cargas uniaxiales en condiciones homogéneas a 7 complejos húmero-tendón-escápula cadavéricos. Con los datos obtenidos se alimentó un modelo tridimensional lineal isotrópico analizando la concentración de esfuerzos de von Mises en el tendón. Resultados: del ensayo uniaxial se obtuvieron curvas esfuerzo-deformación homogéneas para el 20% de la deformación inicial, a partir de las cuales se caracterizó el módulo de Young (14,4 ± 2,3 MPa) y el coeficiente de Poisson (0,14) del tendón. En el modelo se observó una concentración de esfuerzos en la zona central de la cara articular del tendón, cercana a su inserción. Se encontró una disminución del 5% en los esfuerzos al retirar el acromion del modelo. Discusión: se caracterizó de manera exitosa el tendón y se obtuvo un modelo tridimensional del mismo. La distribución de esfuerzos encontrada es compatible con la reportada en la literatura. El acromion no tiene mayor importancia en la magnitud de los esfuerzos en nuestro modelo. Este es el punto de partida para estudiar el mecanismo de falla.
Assuntos
Simulação por Computador , Imageamento Tridimensional , Manguito RotadorRESUMO
A viable blood substitute is still of great necessity throughout the world. Perfluorocarbon-based oxygen carriers (PFCOCs) are emulsions that take advantage of the high solubility of respiratory gases in perfluorocarbons (PFCs). Despite attractive characteristics, no PFCOC is currently approved for clinical uses. Some PFCOCs have failed due to secondary effects of the surfactants employed, like Fluosol DA, whereas others to adverse cerebrovascular effects on cardiopulmonary bypass, such as Oxygent. Further in-depth, rigorous work is needed to overcome the annotated failures and to obtain a safe PFCOC approved for human use. The aim of this study is to review in detail the most-used PFCOCs, their formulation, and preclinical and clinical trials, and to reflect upon causes of failure and strategies to overcome such failures.
Assuntos
Substitutos Sanguíneos/uso terapêutico , Fluorocarbonos/uso terapêutico , Animais , Substitutos Sanguíneos/química , Ensaios Clínicos como Assunto , Emulsões/química , Emulsões/uso terapêutico , Fluorocarbonos/química , Humanos , Falha de TratamentoRESUMO
Use of occluder devices for a patent ductus arteriosus (PDA) closure is restricted to small diameter PDAs and involves high device costs. The objective of this study was to develop a new nitinol implant for the closure of a PDA and to evaluate its safety and efficacy in an animal model. The design consists of a device that promotes thrombus formation in the PDA. The device has a double-cone shape with their vertices joined. The cones are made of a nitinol wire helix with dacron fibers attached. The proximal end of the helix can be screwed to a conventional catheter release wire. In vitro testing was performed to verify the effectiveness of the implantation of the device and its releasing system; all trials (n = 30) were successful, showing accurate placement and release of the device. Complete and successful implantation of the device was achieved in all in vivo experiments (n = 5). There was one case of embolization due to premature detachment; a second device was successfully implanted. Histological evaluation after 42.3 +/- 3.1 days demonstrated complete PDA occlusion. The retrieved PDA showed total closure of the defect, endothelization of the PDA outlets and proper lodging of the device.
Assuntos
Permeabilidade do Canal Arterial/cirurgia , Permeabilidade do Canal Arterial/terapia , Ligas/farmacologia , Animais , Animais Recém-Nascidos , Materiais Biocompatíveis/química , Cateterismo , Bovinos , Embolização Terapêutica/instrumentação , Embolização Terapêutica/métodos , Desenho de Equipamento , Modelos Animais , Próteses e Implantes , Desenho de Prótese/instrumentação , TromboseRESUMO
Oxygen delivery and consumption after hemodilution with a perfluorocarbon-based oxygen carrier (PFCOC) was evaluated at sea level and at 2,600 m above sea level. Fifteen anesthetized rats were subjected to a two-exchange normovolemic hemodilution of 40% of the circulating blood volume each. First exchange was performed with a colloid solution. Second exchange was with 80% PFCOC and 20% colloid. Animals were then ventilated with 100% oxygen. Experiments were performed at barometric pressure of 1.0 atm (sea-level group, n=9) or 0.74 atm (2,600-m group, n=6). Blood gases, hematocrit, fluorocrit, and hemoglobin content were measured at baseline and 15 min after each exchange. After hemodilution, total arterial content was not modified by the PFCOC in either group. In contrast, arteriovenous oxygen difference increased significantly in both groups, as did the oxygen extraction ratio. In the second exchange, although total arterial content was similar between the two groups, the perfluorocarbon and plasma phases contributed significantly more at sea level. Arteriovenous oxygen difference was significantly less at sea level with a higher contribution from the perfluorocarbon and plasma phases. In conclusion, hemodilution with a PFCOC induced changes in oxygen delivery and consumption that differ with altitude. The 2,600-m group exhibited a higher oxygen extraction ratio and arteriovenous oxygen difference, with reduced oxygen delivery and unloading from both the fluorocarbon and plasma phase. Therefore, the efficacy of PFCOCs at 2,600 m above sea level is reduced, and altitude must be taken into account when PFCOCs are used.
Assuntos
Altitude , Substitutos Sanguíneos/farmacologia , Fluorocarbonos/farmacologia , Hemodiluição , Hiperóxia/metabolismo , Oxigênio/sangue , Animais , Transporte Biológico Ativo , Gasometria , Emulsões , Hematócrito , Hemoglobinas/metabolismo , Masculino , Ratos , Ratos Sprague-DawleyRESUMO
Como conclusión la VLP-PFC no muestra ventajas sobre VMC independientemente del PFC utilizado en un modelo experimental de IPA.
Assuntos
Fluorocarbonos , Ventilação PulmonarRESUMO
La porcicultura ha evolucionado a tal manera, que el concepto acerca del cerdo de hace tres décadas como portador de enfermedades y poseer una carne con abundante cantidad de grasa nocivas para la salud humana, pasó a ser considerado hoy en día como un alimento seguro y una de las principales fuentes de proteínas, minerales y vitaminas que se conozcan. Los adelantos en la genética y alimentación porcina han permitido obtener animales con un contenido de colesterol similar a las consideradas carnes blancas. La similitud del cerdo en la fisiología y anatomía cardíaca con la del ser humano, han permitido considerar esta especie como uno de los modelos experimentales más ampliamente utilizados y sus aportes al conocimiento científico son incalculables. En nuestra institución desde hace varios años se ha venido trabajando y ganando experiencia en investigación con porcinos en diferentes áreas, tales como fuentes de prótesis valvulares biológicas principalmente para ser utilizadas en posición aórtica, manjeo anestésico, modelos de reestenosis coronaria mediante trauma con balón y Stents, neuro-intervensionismo con modelos de embolización endovascular cerebral y evaluación de hemosustitutos portadores de oxígeno en porcinos en modelos de bypass cardiovascular
Assuntos
Humanos , Animais , Próteses Valvulares Cardíacas , Suínos , Coração/anatomia & histologia , Coração/fisiologia , Coração/fisiopatologia , Próteses Valvulares Cardíacas/veterinária , Suínos/anatomia & histologia , Suínos/fisiologia , Suínos/cirurgiaRESUMO
Es un estudio prospectivo que se realiza a partir deenero de 1995 en los Servicios de Neurología y Pediatría del Hospital Nacional Guillermo Almenara-IPSS. La epilepsia es refractaria al tratamiento médico convencional entre el 10 y 20 por ciento de todas las series. Siguiendo los criterios establecidos logramos identificar a 18 pacientes entre 2 y 18 años de edad, quienes presentaban innumerables crisis a pesar de las asociaciones de fármacos antiepilépticos que venían usando. A la adición de Lamotrigine pudimos observar una disminución evidente en la frecuencia de las diversas crisis epilépticas que iban en el orden del 79 al 100 por ciento. La mayoría de nuestros pacientes presentaban grado variable de retraso psicomotor y en los que además de la efectividad antiepiléptica mostraban mejoría en las esferas de cognición y de lenguaje. Concluimos que Lamotrigine como terapia de adición es altamente efectiva en el control de epilepsia refractaria al tratamiento médico convencional.
Assuntos
Humanos , Masculino , Pré-Escolar , Feminino , Anticonvulsivantes , Epilepsia , Análise Custo-Benefício , Epilepsia Tipo AusênciaRESUMO
El estudio se realiza en los distritos limeños del Rímac, San Martín de Porras y en Bellavista-Callao de Agosto a Diciembre de 1992. Se entrevistó a 2,016 escolares de 9 a 12 años sobre la presencia de crisis convulsivas generalizadas o parciales y los datos fueron procesados según modelo del National Institute of Health (USA). Se entrevistaron a 1214 varones y 802 mujeres. En Bellavista se encontró una prevalencia de 13.9/1000. En el Rímac encontramos una prevalencia de 13.4/1000 y en San Martín de Porres el resultado fue de 8.5/1000; lo que da como prevalencia global de 11.9/1000 niños con epilepsia.
Assuntos
Humanos , Masculino , Feminino , Adolescente , Prevalência , Epilepsia/epidemiologia , Distribuição por Idade , Distribuição por SexoRESUMO
El presente reporte trata acerca de la importancia de realizar una evaluación electrofisiológica completa en los pacientes con severo compromiso de la conciencia y de la función cerebral, utilizando en forma conjunta la electroencefalografía (EEG), potenciales evocados auditivos de tallo (PEAT), y potenciales evocados somato-sensoriales (PESS). Se examinaron 20 pacientes del servicio de Terapia Intensiva del INNN de la ciudad de México de mayo a diciembre de 1990. Concluyendo que esta evaluación tiene un alto grado de confiabilidaden el diagnóstico y pronóstico tanto de sobrevida como de calidad de sobrevida en los pacientes estudiados.