OBJECTIVES:To analyze the outcome of vascular procedures performed in patients with COVID-19 infection during the 2020 pandemic. METHODS:This is a multicenter, prospective observational cohort study. We analyzed data from 75 patients with COVID-19 infection undergoing vascular surgery procedures in 17 hospitals across Spain and Andorra between March and May 2020. The primary end point was 30-day mortality. Clinical Trials registry number NCT04333693. RESULTS:The mean age was 70.9 (45-94) and 58 (77.0%) patients were male. Around 70.7% had postoperative complications, 36.0% of patients experienced respiratory failure, 22.7% acute renal failure, and 22.7% acute respiratory distress syndrome (ARDS). All-cause 30-days mortality rate was 37.3%. Multivariate analysis identified age >65 years (P = 0.009), American Society of Anesthesiologists (ASA) classification IV (P = 0.004), preoperative lymphocyte count <0.6 (×109/L) (P = 0.001) and lactate dehydrogenase (LDH) >500 (UI/L) (P = 0.004), need for invasive ventilation (P = 0.043), postoperative acute renal failure (P = 0.001), ARDS (P = 0.003) and major amputation (P = 0.009) as independent variables associated with mortality. Preoperative coma (P = 0.001), quick Sepsis Related Organ Failure Assessment (qSOFA) score ≥2 (P = 0.043), lymphocytes <0.6 (×109/L) (P = 0.019) leucocytes >11.5 (×109/L) (P = 0.007) and serum ferritin >1800 mg/dL (P = 0.004), bilateral lung infiltrates on thorax computed tomography (P = 0.025), and postoperative acute renal failure (P = 0.009) increased the risk of postoperative ARDS. qSOFA score ≥2 was the only risk factor associated with postoperative sepsis (P = 0.041). CONCLUSIONS:Patients with COVID-19 infection undergoing vascular surgery procedures showed poor 30-days survival. Age >65 years, preoperative lymphocytes <0.6 (x109/L) and LDH >500 (UI/L), and postoperative acute renal failure, ARDS and need for major amputation were identified as prognostic factors of 30-days mortality.

espanolLa angulacion en diferentes planos del cuello de los aneurismas de la aorta abdominal puede considerarse un factor limitante en la implantacion de diferentes protesis en el tratamiento de esta patologia. Es necesario realizar una valoracion de los angulos en diferentes planos en estudios rutinarios previos a la planificacion de los procedimientos y muy especialmente mediante AngioTAC. Se valora en el estudio la medicion de 507 pacientes portadores de aneurismas de aorta abdominal y tratados por metodos endovasculares y de los que se disponia la informacion completa a nivel de angulaciones del cuello. Se valoran en un estudio prospectivo y descriptivo la situacion de este sector aortico aportando informacion al respecto con respecto a la tendencia en la presentacion morfologica de la aorta en enfermos portadores de esta patologia. EnglishAngulation in different planes of the neck of abdominal aortic aneurysms may be considered a limiting factor in the implantation of different prostheses in the treatment of this pathology. It is necessary to make an assessment of the angles in different planes in routine studies prior to the planning of the procedures and especially by AngioTAC. The study evaluated the measurement of 507 patients with abdominal aortic aneurysms and treated endovascular procedures and of whom the complete information was available at the level of neck angulations. In a prospective and descriptive study the situation of this aortic sector was evaluate d, contributing information about the tendency in the morphological presentation of the aorta in patients with this aetiology.

Aortic dissection is one of the cardiovascular diseases with a high morbidity and mortality, for which the ideal treatment continues to be a challenge.There is still no absolute evidence to support the routine use of thoracic endovascular aortic repair (TEVAR) in the treatment of type B aortic dissection, nor in favour of medical treatment.The short-term follow up of complicated type B dissections improves with endovascular treatment. In survivors with type B aortic dissection, endovascular treatment is associated with a higher survival and lower disease progression at 5 years. In stable cases of type B dissection and with a favourable anatomy, endovascular repair could prevent delayed complications and achieve better aortic remodelling. By using the safest endovascular procedures, due to the improved skills of the surgeons and the current technology, TEVAR could be considered as first line treatment in type B aortic dissection, owing to its capacity to heal and remodel the aorta, and decreasing the appearance of complications in the medium to long term. (C) 2014 SEACV. Published by Elsevier Espana, S.L.U. All rights reserved.

The aim of this study is to assess how the shape of the abdominal aortic aneurysms (AAA) affects the hemodynamic wall stresses. With this purpose, different AAAs are studied through simplified models based on geometrical parameters of the aneurism such as its maximum and minimum diameter, length and asymmetry. Then, a computational fluid dynamics analysis is performed on the simplified models in order to compute pressure and wall shear stresses on the aneurysm sac. The results obtained show that blood pressure is the main dynamic load acting on the artery wall, and that the morphology of the aneurysm could be a good indicator of risk of failure. Furthermore, the computational results are compared with patient-specific real models with the objective to assess the reliability of the proposed simplified approach. (C) 2013 CIMNE (Universitat Politecnica de Catalunya). Published by Elsevier Espana, S.L.U. All rights reserved.

El Aneurisma de Aorta Abdominal es la dilatación localizada, irreversible y progresiva que experimenta la pared aortica. Esta patología ha sido reconocida como un importante problema de salud, puesto que su ruptura está asociada mayormente a consecuencias fatales. La falta de criterios fiables, respecto a los actualmente utilizados, para la evaluación del riesgo de ruptura, constituye un inconveniente en la gestión clínica de la enfermedad. El presente trabajo tiene como objetivo evaluar el riesgo de ruptura de Aneurismas de Aorta Abdominal, mediante indicadores numéricos, como es previsto por el enfoque biomecánico. Fueron utilizadas técnicas de modelación por elementos finitos para determinar el comportamiento del flujo sanguíneo y el estado tensional de la pared arterial. Los resultados mostraron que ninguno de los aneurismas analizados presenta riesgo de ruptura elevado y que la evaluación del riesgo de ruptura mediante índices numéricos, es un camino viable para prever la ruptura de un aneurisma específico.Palabras claves: aneurisma de aorta abdominal, factores biomecánicos, interacción fluido-sólido, riesgo de ruptura.______________________________________________________________________________AbstractAbdominal Aortic Aneurysm is a localized, progressive and permanent dilation of the infra-renal aorta.AAA has increasingly been recognized as an important health problem in the last decades. The AAA rupture is mostly associated with fatal consequences. The lack of more reliable criteria for rupture riskassessing, results in a problem in the clinical management of the disease. This paper aims to assess the rupture risk of abdominal aortic aneurysms by means of numerical indexes, as envisaged by the biomechanical approach. Finite Volume Techniques were used to determine the blood flow behavior within aneurysmatic sac and the structural state of the arterial wall. The results showed that none of the assessed aneurysms is at high rupture risk. The rupture risk assessment by using numerical indices is a viable way to predict the rupture of a specific aneurysm.Key words: abdominal aortic aneurysm, biomechanical factors, fluid-solid interaction, rupture risk.

Calcifying nanoparticles (NPs) have been detected recently in calcified human arterial specimens and are involved in the process of calcification. This study was designed to test the hypothesis that human-derived NPs could worsen the response to arterial endothelial injury and induce vascular calcification.The right carotid artery of 24 New Zealand rabbits was injured with an angioplasty balloon. Animals were perfused intravenously with saline (100 mL) during the experiment and divided into three groups: group-A, control; group-B, exposed to NPs (2 mL) obtained from calcified aortic valves; and group-C, exposed to NPs (2 mL) and treated postoperatively with atorvastatin (2.5 mg/kg/24 h). At 30 days, both carotid arteries were removed and examined histologically. Blood measurements were monitored during the study.The intimal hyperplasia area was significantly larger in the injured right carotid artery compared with the left unoperated carotid artery in all groups. There was no significant variation in medial area between groups. Morphometrically, the intima/media ratio (IMR) was significantly higher in damaged carotids compared with controls. A significant increase of IMR was found in group-B (1.81 ± 0.41) compared with group-A (0.38 ± 0.59; p = .004) or group-C (0.89 ± 0.79; p = .035). Differences between groups C and A were not significant (p = .064). Calcifications were observed in six animals, all of which had been exposed to NPs (4 in group-B, 2 in group-C, p = .027). Plasma levels of cholesterol and triglycerides remained stable.This research confirms the ability of systemic inoculation of human-derived NPs to accelerate hyperplasia and stimulate calcification in localized areas of arteries previously submitted to endothelial damage, while it was harmless in healthy arteries. Atorvastatin was demonstrated to slow down this process.

There is no evidence on which to base the ideal technique for the treatment of aorto-enteric fistulas (AEFs). A 54-year-old man presented with an AEF. He had previously undergone aortobifemoral bypass with an end-to-side proximal anastomosis. An Endurant II aorto-uni-iliac endograft and a Complete SE stent soaked in rifampicin were implanted. After 12 hours, a second staged intervention was performed. The original graft was removed and the communication with the duodenum was repaired. A staged combination of endovascular repair for acute bleeding control and open surgical treatment, combined with systemic and local antibiotics might be considered the option of choice.

Se valora el dano producido por los metodos de clampaje temporal extravascular en un modelo animal en carotida de rata, comparando el dano vascular en sistemas de oclusion tangencial (clamp vascular dentado y clamp vascular no dentado) y sistemas de oclusion circunferencial (lazo de potts y torniquete de rumel)

Resumen es: El Aneurisma de Aorta Abdominal es la dilatacion localizada, irreversible y progresiva que experimenta la pared aortica. Esta patologia ha sido reconocid...

Abdominal aortic aneurysms (AAAs) rupture is one of the main causes of death in the world. This is a very complex phenomenon that usually occurs “without previous warning”. Currently, criteria to assess the aneurysm rupture risk (peak diameter and growth rate) cannot be considered as reliable indicators. In order to improve the predicting of AAA rupture risk, it had been developed a simple method, where the main geometric parameters of aneurysms have been linked into six biomechanical factors, which have been combined to obtain a dimensionless rupture risk index, RI(t). Based on the initial results of the validation tests of this method a broader prospective randomized control study with two hundred and one patients at the Clinic Hospital of Valladolid-Spain using a new set of weighted coefficient values for each biomechanical factor has been carried out in this work. The outcomes of the present work have shown that it is possible to implement a clinical assessment of the AAA rupture risk through its geometric parameters. Defined quantitative indicator is easy to understand. It allows estimating the aneurysms rupture risks and is able to identify the ones that ruptures even when its peak diameter is less than the threshold value. It also identifies those cases where the rupture should not occur regardless the maximum diameter is greater than the rupture threshold value and consequently avoids the patients to be submitted to surgical procedure. According to the results, the most relevant geometric biomechanical factors are the deformation rate and the growth rate. Beside these ones, but less important, resulted the saccular index.

© 2012 Vilalta et al., licensee InTech. This is an open access chapter distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Biomechanical Approach to Improve the Abdominal Aortic Aneurysm (AAA) Rupture Risk Prediction

El síndrome del ligamento arcuato medio (SLAM), o síndrome de compresión del tronco celiaco, es causado por la compresión extrínseca del ligamento arcuato medio, bandas fibrosas prominentes y tejido ganglionar periaórtico. En muchas ocasiones es asintomático, pero puede presentar síntomas como dolor abdominal posprandial o durante el ejercicio náuseas, vómitos y pérdida de peso. Presentamos tres pacientes, uno de ellos asintomático. Los otros dos casos precisaron tratamiento quirúrgico, en uno de ellos mediante liberación laparoscópica y en el otro mediante cirugía abierta. En ambos casos se obtuvo mejoría clínica y seguimiento mediante ecografía doppler-color satisfactorio. El SLAM representa una entidad poco frecuente de dolor abdominal. Las técnicas diagnósticas menos invasivas, como la ecografía doppler-color para el screening y la angioTC preoperatoria, obtienen buenos resultados en comparación con la arteriografía. El tratamiento quirúrgico mediante abordaje laparoscópico, con o sin asociación de tratamiento revascularizador endovascular, constituye una técnica terapéutica segura y eficaz.

An experimental investigation was undertaken to study the characteristics of curved turbulent water jets produced from a vertical slot diffuser with sharp protrusions at the exit plane. The experiments were performed at two different flow rates for which the Reynolds number based on slot width and average velocity were 2050 and 4100. A high resolution particle image velocimetry system was used to perform detailed velocity measurements which were post-processed to obtain the mean velocities, Reynolds stresses and turbulence kinetic energy. The decay of the centerline mean velocity and jet half-width were also obtained to evaluate the mixing characteristics of the present slot configuration vis-à-vis results reported in previous studies. It was observed that the mixing characteristics of the slot configuration investigated in this study are superior to most of the sharp-edged nozzle configurations and curved jets studied in the past. The effects of streamline curvature on the Reynolds stresses in the convex and concave regions were also examined. The results clearly demonstrated that streamline curvature significantly enhanced the level of the streamwise turbulence intensity in the convex region more than in the concave region. On the contrary, the Reynolds shear stress and transverse turbulence intensity are much larger in the concave region than in the convex region. These results, together with the distributions of the Reynolds stress ratios across the jet, provide clear indications that turbulence models that assume local equilibrium and isotropy will not be able to accurately reproduce the flow characteristics of curved turbulent jets.