237 research outputs found

    Repair of quadricuspid aortic valve by bicuspidization: a novel technique

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    Quadricuspid aortic valve (QAV) is a rare congenital lesion, generally manifesting with valve regurgitation. Standard treatment involves valve replacement, though anecdotal cases of successful repair by means of valve tricuspidization have been reported. Here, the successful application of a repair technique previously unreported in the setting of QAV is described

    The Early and Middle Holocene Lithic Industries of Ifri n’Etsedda (Eastern Rif, Morocco)

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    Archaeological research has been carried out in the Eastern Rif (Morocco) since 1995 by a collaborative Moroccan-German research team. A major topic of the project is the transition from hunting-gathering to food production and related cultural developments. Innovations such as pottery and domesticated species appeared around 7.6 ka calBP. The cultivation of cereals and pulses is evident at that time. Two of the most important sites in the area are Ifri Oudadane and Ifri n’Etsedda. Both provide Epipaleolithic as well as Neolithic deposits. While innovative technologies such as pottery production and cultivation indicate external influences, lithic artifacts demonstrate local technological and behavioral traditions. Therefore, the study of lithic industries is crucial to understanding the nature of cultural continuity and discontinuity between the hunting-gathering and agricultural populations in the Eastern Rif. Ifri n’Etsedda provides two distinct Epipaleolithic deposits and thus offers the opportunity to study possible changes throughout the Epipalaeolithic and relationship to the later Early Neolithic (ENC). In combination with the earlier phases of Early Neolithic assemblages (ENA, ENB) at Ifri Oudadane, we are now in a better position to understand the development of early-to-mid Holocene lithic technology in the Eastern Rif. We show that the lithic record of Ifri n’Etsedda does not indicate any significant change in raw material supply, blank production, and tool distribution from the Early Epipaleolithic to the Early Neolithic B. Therefore, we argue for behavioral continuity from the Epipaleolithic to the Neolithic period. In contrast, the assemblages of the Early Neolithic C show changes in lithic technology

    An alternative method for neonatal cerebro-myocardial perfusion.

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    Several techniques have already been described for selective cerebral perfusion during repair of aortic arch pathology in children. One method combining cerebral with myocardial perfusion has also been proposed. A novel technique is reported here for selective and independent cerebro-myocardial perfusion for neonatal and infant arch surgery. Technical aspects and potential advantages are discussed

    Role of calcium desensitization in the treatment of myocardial dysfunction after deep hypothermic circulatory arrest

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    Abstract Introduction Rewarming from deep hypothermic circulatory arrest (DHCA) produces calcium desensitization by troponin I (cTnI) phosphorylation which results in myocardial dysfunction. This study investigated the acute overall hemodynamic and metabolic effects of epinephrine and levosimendan, a calcium sensitizer, on myocardial function after rewarming from DHCA. Methods Forty male Wistar rats (400 to 500 g) underwent cardiopulmonary bypass (CPB) through central cannulation and were cooled to a core temperature of 13°C to 15°C within 30 minutes. After DHCA (20 minutes) and CPB-assisted rewarming (60 minutes) rats were randomly assigned to 60 minute intravenous infusion with levosimendan (0.2 μg/kg/min; n = 15), epinephrine (0.1 μg/kg/min; n = 15) or saline (control; n = 10). Systolic and diastolic functions were evaluated at different preloads with a conductance catheter. Results The slope of left ventricular end-systolic pressure volume relationship (Ees) and preload recruitable stroke work (PRSW) recovered significantly better with levosimendan compared to epinephrine (Ees: 85 ± 9% vs 51 ± 11%, P\u3c0.003 and PRSW: 78 ± 5% vs 48 ± 8%, P\u3c0.005; baseline: 100%). Levosimendan but not epinephrine reduced left ventricular stiffness shown by the end-diastolic pressure-volume relationship and improved ventricular relaxation (Tau). Levosimendan preserved ATP myocardial content as well as energy charge and reduced plasma lactate concentrations. In normothermia experiments epinephrine in contrast to Levosimendan increased cTnI phosphorylation 3.5-fold. After rewarming from DHCA, cTnI phosphorylation increased 4.5-fold in the saline and epinephrine group compared to normothermia but remained unchanged with levosimendan. Conclusions Levosimendan due to prevention of calcium desensitization by cTnI phosphorylation is more effective than epinephrine for treatment of myocardial dysfunction after rewarming from DHCA

    Is it possible to assess the best mitral valve repair in the individual patient? Preliminary results of a finite element study from magnetic resonance imaging data

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    ObjectivesFinite element modeling was adopted to quantitatively compare, for the first time and on a patient-specific basis, the biomechanical effects of a broad spectrum of different neochordal implantation techniques for the repair of isolated posterior mitral leaflet prolapse.MethodsCardiac magnetic resonance images were acquired from 4 patients undergoing surgery. A patient-specific 3-dimensional model of the mitral apparatus and the motion of the annulus and papillary muscles were reconstructed. The location and extent of the prolapsing region were confirmed by intraoperative findings, and the mechanical properties of the mitral leaflets, chordae tendineae and expanded polytetrafluoroethylene neochordae were included. Mitral systolic biomechanics was simulated under preoperative conditions and after 5 different neochordal procedures: single neochorda, double neochorda, standard neochordal loop with 3 neochordae of the same length and 2 premeasured loops with 1 common neochordal loop and 3 different branched neochordae arising from it, alternatively one third and two thirds of the entire length.ResultsThe best repair in terms of biomechanics was achieved with a specific neochordal technique in the single patient, according to the location of the prolapsing region. However, all techniques achieved a slight reduction in papillary muscle forces and tension relief in intact native chordae proximal to the prolapsing region. Multiple neochordae implantation improved the repositioning of the prolapsing region below the annular plane and better redistributed mechanical stresses on the leaflet.ConclusionsAlthough applied on a small cohort of patients, systematic biomechanical differences were noticed between neochordal techniques, potentially affecting their short- to long-term clinical outcomes. This study opens the way to patient-specific optimization of neochordal techniques
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