Morphological evaluation of experimental autologous rectus fascia sheath vascular grafts used for arterial replacement in a dog model

Although experimental autologous patch or tubular conduit vascular grafts made from the internal rectus fascia sheath (IRFS) have been reported in the literature, thorough morphological evaluation and verification of the histological arterialisation of such grafts are lacking. Four purpose-bred Beagle dogs were utilised to create eight arterial internal rectus fascia sheath (ARFS) grafts implanted between bisected ends of the external iliac arteries. Four out of the eight ARFS grafts were patent after three months. Haematoxylin-eosin and Azan staining verified that the grafts gained a vessel-like layered structure with the presence of large amounts of collagen fibres. Although the inner surface of the intact IRFS was originally covered with claudin-5-negative and pancytokeratin-positive mesothelial cells in control samples, the internal cells of the ARFS grafts became claudin-5 positive and pancytokeratin negative like in intact arteries. Spindle-shaped cells of the wall of ARFS grafts were α-smooth muscle actin (α-SMA) positive just like the smooth muscle cells of intact arteries, but α-SMA immunoreactivity was negative in the intact IRFS. According to these findings, the fibroblast cells of the ARFS graft have changed into myofibroblast cells. The study has proved that ARFS grafts may be used as an alternative in arterial replacement, since the graft becomes morphologically and functionally similar to the host vessel via arterialisation

Incidence, etiology, and outcomes of pre- and post-operative atrial fibrillation in mitral valve procedures: a review

Although pre-procedural and post-procedural atrial fibrillation occur commonly in mitral valve (MV) patients, the impact on patient outcomes and resource utilization has not been well documented. A comprehensive PubMed review was performed using a combination of MeSH terms related to atrial fibrillation, MV disease, MV and atrial fibrillation procedures, and medical management. Additional publications were selected from the reference lists of studies identified in the literature search. This review found that several studies conflict with the short-term outcomes associated with pre- and post-operative atrial fibrillation in MV patients. In general, both pre- and post-operative atrial fibrillation have clear negative long-term impacts on MV patients’ mortality and risk of stroke, major bleeding and other thromboembolic events. Surgical ablation for pre-operative atrial fibrillation and transcatheter ablation for medically resistant post-operative atrial fibrillation appears to be safe and effective procedure; these percutaneous and surgical interventions have been documented to mitigate MV-related thromboembolic risk. For MV patients, evidence suggests that the first step should be to optimize the current medical therapy; for persistent symptoms not addressed medically, ablation procedures should be considered. To optimize MV patients’ quality of care, however, additional research appears warranted to prevent long-term adverse outcomes

Erdbebenbelastung auf Offshorebauwerke Schlussbericht

The objective of the R and D-project 'Earthquake Loading on Offshore Structures' is the development of a practically applicable and code conforming design concept for Concrete Offshore Monotowers. The hydrodynamic analysis has been carried out by the Technical University of Hamburg Harburg, Department of Offshore Technology II (TUHH, Arbeitsgebiet Meerestechnik II). The structural design concept has been developed by the Technical Staff of Bilfinger and Berger Bauaktiengesellschaft in Cooperation with the Gesellschaft fuer Schwingungsuntersuchungen und dynamische Pruefmethoden mbH in Mannheim. As the main results of the research project the following is available: 1. Easy to use graphic solutions for the hydrodynamic actions and fluid-structure-interaction of monotowers of arbitrary geometrical shape, 2. A consistent design concept, where fluid-structure-interaction is implemented in a determination of earthquake effects by the widely used method of design response spectra. Besides some basic investigations into the mechanics of fluid actions on earthquake excited bodies especailly the importane of the earthquake for the design of the structure has been analysed by so called earthquake factors. In addition neighbouring problems of fluid structure interaction of liquid storage tanks and arch dams has been discussed. This final report contains a comprehensive description of the results of the work. Previously released intermediate reports as well as publications and presentations from the project are included in the appendix. (orig.)Das Ziel des Forschungsprojektes Erdbebenbelastung von Offshorebauwerken war die Entwicklung eines praxisgerechten und normenkonformen Konzepts fuer die Bemessung von Offshore-Beton-Monotowern. Die hydrodynamische Analyse wurde von der TUHH, Arbeitsgebiet Meerestechnik II, erarbeitet, waehrend das Bemessungskonzept im Technischen Buero von Bilfinger und Berger Bauaktiengesellschaft in Zusammenarbeit mit der Gesellschaft fuer Schwingungsuntersuchungen und dynamische Pruefmethoden mbH in Mannheim entwickelt wurde. Als wesentliche Arbeitsergebnisse liegt nunmehr vor: 1. Uebersichtsgrafiken fuer die Abschaetzung der Wasserwirkung auf Bauwerke im Frequenzbereich von Erdbeben fuer variable Geometrie zusammengesetzter Zylinder, 2. ein konsistentes Bemessungskonzept, in welchem die Bauwerks-Wasserwechselwirkung bei einer Bemessung mit Antwortspektren beruecksichtigt werden kann. Neben einigen Untersuchungen zur mechanischen Problematik wurde auch die Beurteilung der Relevanz des Lastfalles Erdbeben anhand von bauteilbezogenen Erdbebenfaktoren beschrieben, sowie ein Hinweis auf die Behandlung der benachbarten Problemstellung bei fluessigkeitsgefuellten Behaeltern und Bogenstaumauern gegeben. Der Schlussbericht enthaelt eine umfassende Darstellung der Arbeitsergebnisse des Forschungsprojektes. Abgeschlossene Teilberichte sowie Veroeffentlichungen aus dem Forschungsprojekt sind im Anhang zusammengefasst. (orig.)Available from TIB Hannover: F95B1255+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEBundesministerium fuer Forschung und Technologie (BMFT), Bonn (Germany)DEGerman

Atrial fibrillation in mechanical circulatory support patients

Atrial fibrillation (AF) is known to be one of the most common arrhythmias noted in cardiac procedures and is frequently associated with heart failure. As frequent interventions for patients with heart failure involve implantation of mechanical circulatory assist devices (e.g., left ventricular assist devices), it is timely to review the role this arrhythmia has on adverse clinical outcomes. A comprehensive literature search was conducted for PubMed. Relevant medical subject heading (MeSH) terms used in the initial literature search include “Heart-Assist Devices”, “Extracorporeal Membrane Oxygenation”, “Atrial Fibrillation”, “Heart Failure”, “Mortality”, “Hospital Readmission”, “stroke”, “Postoperative Complications”. In this review, the relevant literature was highlighted to identify the incidence, clinical impacts, and management of AF surrounding mechanical circulatory support implantation. The incidence of AF in this mechanical circulatory support device population was similar to that of patients with other cardiac procedures (10%-40%). Moreover, in most studies, preoperative AF was not significantly associated with adverse outcomes. In contrast, however, it appears that postoperative atrial fibrillation may predispose patients to increased risk for thromboembolic events and adverse long-term outcomes