FRP Offshore Structure Connections Optimization and Validation by Classification Society standards

This paper discusses the use of composite materials in the design process of a horizontal bracing to column connection of an offshore semi-submersible platform to support two wind turbines. The geometry of the connection was optimized to improve the performance and reliability of the connection, columns and bracing tubes. These offshore foundations usually deal with massive structural tubes, and they are used to fit a huge amount of stiffeners. This paper will show how using some horizontal stiffeners combined with their intersection with horizontal bracings tubes, can improve drastically the behavior of the connection. A comparison between conventional materials (steel) and advanced materials (E-glass fibres and epoxy matrix) was performed and it was demonstrated how the use of composite materials makes necessary to modify the connection geometry and configuration to obtain an equivalent performance. This is due to the very different stiffness behavior shown by composites and steel. Therefore, the design of an offshore connection must be approached differently according to the used material. The composite laminate layout design process was also made. The material was evaluated using a Bureau Veritas normative note specifically applicable to composite ship hulls, but adapted to the needs of the materials used in this design, in terms of raw material requirements. The design process of a laminate panel of the connection is shown using the above mentioned standard. All data and results shown here were harvested within the scope of the European research project Fibregy (EU Horizon 2020, Ref. 952966)

Short-course thrombolysis as the first line of therapy for cardiac valve thrombosis

AbstractObjective: To retrospectively evaluate the clinical and echocardiographic criteria of thrombolytic therapy for mechanical heart valve thrombosis. Methods: Nineteen consecutive patients with 22 instances of prosthetic heart valve thrombosis (14 mitral, 2 aortic, 3 tricuspid, and 3 pulmonary) were treated with short-course thrombolytic therapy as first option of treatment in absence of contraindications. The thrombolytic therapy protocol consisted of streptokinase (1,500,000 IU in 90 minutes) (n = 18) in one (n = 7) or two (n = 11) cycles or recombinant tissue-type plasminogen activator (100 mg in 90 minutes) (n = 4). Results: Overall success was seen in 82%, immediate complete success in 59%, and partial success in 23%. Six patients without total response to thrombolytic therapy underwent surgery, and pannus was observed in 83%. Six patients showed complications: allergy, stroke, transient ischemic attack, coronary embolism, minor bleeding, and one death. At diagnosis, 10 patients evidenced atrial thrombus by transesophageal echocardiography, 3 of whom experienced peripheral embolism during thrombolysis. Four episodes of rethrombosis were observed (16%). The survivorship was 84% with a mean follow-up of 42.6 months. Conclusions: A short-course of thrombolytic therapy may be considered first-line therapy for prosthetic heart valve thrombosis. The risk of peripheral embolism may be evaluated for the presence of atrial thrombus by transesophageal echocardiography at diagnosis. (J Thorac Cardiobasc Surg 1998;115:780-4

Fibrilación auricular en el postoperatorio de cirugía cardiaca : factores predisponentes y complicaciones

La fibril·lació auricular és una complicació freqüent en el postoperatori de cirurgia cardíaca que empitjora el pronòstic d'aquest procediment. Per aquest motiu decidim realitzar un estudi prospectiu observacional amb la finalitat de detectar factors relacionats amb l'aparició de fibril·lació auricular postquirúrgica, en el qual es van incloure 101 pacients intervinguts de cirurgia cardíaca en un període de 3 mesos. Es van recollir dades preoperatòries i intraoperatòries, així com complicacions postquirúrgiques. Es va objectivar associació estadística entre l'aparició de fibril·lació auricular i el tipus i durada de la cirurgia, així com augment en les complicacions i en l'estada mitjana.La fibrilación auricular es una complicación frecuente en el postoperatorio de cirugía cardiaca que empeora el pronóstico de este procedimiento. Por dicho motivo decidimos realizar un estudio prospectivo observacional con el fin de detectar factores relacionados con la aparición de fibrilación auricular postquirúrgica, en el que se incluyeron 101 pacientes intervenidos de cirugía cardiaca en un periodo de 3 meses. Se recogieron datos preoperatorios e intraoperatorios, así como complicaciones postquirúrgicas. Se objetivó asociación estadística entre la aparición de fibrilación auricular y el tipo y duración de la cirugía, así como aumento en las complicaciones y en la estancia media

Summation and Cancellation Effects on QRS and ST-Segment Changes Induced by Simultaneous Regional Myocardial Ischemia

Simultaneous ischemia in two myocardial regions is a potentially lethal clinical condition often unrecognized whose corresponding electrocardiographic (ECG) patterns have not yet been characterized. Thus, this study aimed to determine the QRS complex and ST-segment changes induced by concurrent ischemia in different myocardial regions elicited by combined double occlusion of the three main coronary arteries. For this purpose, 12 swine were randomized to combination of 5-min single and double coronary artery occlusion: Group 1: left Circumflex (LCX) and right (RCA) coronary arteries (n = 4); Group 2: left anterior descending artery (LAD) and LCX (n = 4) and; Group 3: LAD and RCA (n = 4). QRS duration and ST-segment displacement were measured in 15-lead ECG. As compared with single occlusion, double LCX+RCA blockade induced significant QRS widening of about 40 ms in nearly all ECG leads and magnification of the ST-segment depression in leads V1-V3 (maximal 228% in lead V3, p < 0.05). In contrast, LAD+LCX or LAD+RCA did not induce significant QRS widening and markedly attenuated the ST-segment elevation in precordial leads (maximal attenuation of 60% in lead V3 in LAD+LCX and 86% in lead V5 in LAD+RCA, p < 0.05). ST-segment elevation in leads V7-V9 was a specific sign of single LCX occlusion. In conclusion, concurrent infero-lateral ischemia was associated with a marked summation effect of the ECG changes previously elicited by each single ischemic region. By contrast, a cancellation effect on ST-segment changes with no QRS widening was observed when the left anterior descending artery was involved

Persistent Pulmonary Hypertension in Corrected Valvular Heart Disease: Hemodynamic Insights and Long-Term Survival.

Background The determinants and consequences of pulmonary hypertension after successfully corrected valvular heart disease remain poorly understood. We aim to clarify the hemodynamic bases and risk factors for mortality in patients with this condition. Methods and Results We analyzed long-term follow-up data of 222 patients with pulmonary hypertension and valvular heart disease successfully corrected at least 1 year before enrollment who had undergone comprehensive hemodynamic and imaging characterization as per the SIOVAC (Sildenafil for Improving Outcomes After Valvular Correction) clinical trial. Median (interquartile range) mean pulmonary pressure was 37 mm Hg (32-44 mm Hg) and pulmonary artery wedge pressure was 23 mm Hg (18-26 mm Hg). Most patients were classified either as having combined precapillary and postcapillary or isolated postcapillary pulmonary hypertension. After a median follow-up of 4.5 years, 91 deaths accounted for 4.21 higher-than-expected mortality in the age-matched population. Risk factors for mortality were male sex, older age, diabetes mellitus, World Health Organization functional class III and higher pulmonary vascular resistance-either measured by catheterization or approximated from ultrasound data. Higher pulmonary vascular resistance was related to diabetes mellitus and smaller residual aortic and mitral valve areas. In turn, the latter correlated with prosthetic nominal size. Six-month changes in the composite clinical score and in the 6-minute walk test distance were related to survival. Conclusions Persistent valvular heart disease-pulmonary hypertension is an ominous disease that is almost universally associated with elevated pulmonary artery wedge pressure. Pulmonary vascular resistance is a major determinant of mortality in this condition and is related to diabetes mellitus and the residual effective area of the corrected valve. These findings have important implications for individualizing valve correction procedures. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT00862043.This study was funded by the Instituto de Salud Carlos III, Ministerio de Ciencia e Innovación, Spain, the European Union–European Regional Development Fund (EC07/90772 and PI19/00649), and the Consorcio de Investigación Biomédica en Red de Enfermedades Cardiovasculares (CIBERCV).S