Influence of Transvalvar Pressure Gradient on Hinge Washing in Closed Mechanical Prosthetic Cardiac Valves Under Pulmonary Pressure Conditions: A Comparative In Vitro Study

2019 ◽  
Vol 10 (2) ◽  
pp. 145-150
Author(s):  
Hanna Pragt ◽  
Joost P. van Melle ◽  
Massimo A. Mariani ◽  
Gijsbertus J. Verkerke ◽  
Tjark Ebels
Keyword(s):  
Pressure Difference ◽  
Diastolic Pressure ◽  
In Vitro Study ◽  
Test Fluid ◽  
Closed Position ◽  
Valve Position ◽  
The Right ◽  
Bileaflet Mechanical Valves ◽  
The Relationship

Objective: Hinge washing is a crucial factor in the prevention of mechanical prosthetic valvar thrombosis, especially in the pulmonary valve position. The aim of this laboratory study was to determine the relationship between pressure difference and the amount of hinge washing in the closed position, using the pressures that are normal for the right ventricle and pulmonary artery. Methods: In an in vitro setting, four different bileaflet mechanical valves were tested for hinge washing in closed position. Based on similarity in inner diameter (range: 20.5-21.4 mm), the following valves were tested: Abbott SJM Regent size 23, Cryolife On-X size 23, LivaNova Carbomedics-R size 25, Medtronic Open Pivot (M-OP)-A size 25. Tests were carried out in a range between 3 and 100 mm Hg pressure difference, using water as a test fluid. The amount of leakage per minute through the closed valve was measured. Results: All four valves showed an increase in leakage with increasing transvalvar gradient, and the relationship between pressure and leakage behaves in logarithmic fashion. Leakage under normal pulmonary diastolic pressure conditions (10 mm Hg) was between 23.3% and 29.3% of the leakage under aortic diastolic pressure conditions (80 mm Hg). The Cryolife On-X valve showed the highest closed leakage volume under pulmonary conditions (10 mm Hg) 0.254 ± 0.01 (L/min), where the Medtronic M-OP showed the lowest leakage volume with 0.125 ± 0.014 (mL/min). Conclusion: Hinge washing is related to transvalvar pressure difference in closed position. Valve brands differed significantly from each other in the amount of hinge washing.

scholarly journals P1591Assessment of flow disturbances in the right ventricle: an in vitro study using a novel heart model

EP Europace ◽  
2017 ◽  
Vol 19 (suppl_3) ◽  
pp. iii339-iii339
Author(s):  
U. Gulan ◽  
AM. Saguner ◽  
D. Akdis ◽  
C. Brunckhorst ◽  
M. Holzner ◽  
...  
Keyword(s):  
Right Ventricle ◽  
In Vitro Study ◽  
Vitro Study ◽  
Heart Model ◽  
Flow Disturbances ◽  
The Right

scholarly journals P2834An in vitro study on the influence of increased heart rate on the right ventricular kinetic energy and shear stresses

2018 ◽  
Vol 39 (suppl_1) ◽  
Author(s):  
U Gulan ◽  
A M Saguner ◽  
D Akdis ◽  
A Denegri ◽  
M X Miranda ◽  
...  
Keyword(s):  
Heart Rate ◽  
Kinetic Energy ◽  
Right Ventricular ◽  
In Vitro Study ◽  
Vitro Study ◽  
Shear Stresses ◽  
The Right

Abnormal Action Potential Responses to Halothane in Heart Muscle Isolated from Malignant Hyperthermia-susceptible Pigs

1995 ◽  
Vol 82 (4) ◽  
pp. 947-953. ◽  
Author(s):  
Norbert Roewer ◽  
Clemens Greim ◽  
Eckhart Rumberger ◽  
Jochen Schulte am Esch
Keyword(s):  
Malignant Hyperthermia ◽  
Action Potentials ◽  
Myocardial Function ◽  
In Vitro Study ◽  
Resting Potential ◽  
Cardiac Symptoms ◽  
Cardiac Dysrhythmias ◽  
Malignant Hyperthermia Susceptible ◽  
The Right

Background During human and porcine malignant hyperthermia (MH), cardiac dysrhythmias and altered myocardial function can be observed. It is unknown whether a primary abnormality in cardiac muscle contributes to the cardiac symptoms during MH. An abnormal response to halothane has recently been demonstrated in action potentials (APs) from MH-susceptible (MHS) human skeletal muscles. We investigated the electrophysiologic properties in trabeculae isolated from the right ventricles of normal (MHN) and MHS pigs. Methods The experiments were performed on electrically stimulated (1 Hz) trabeculae isolated from the right ventricles of MHS and MHN pigs. Resting membrane potentials, APs, and tension were measured with and without the presence of 1% halothane. In addition, the halothane-equilibrated muscles were exposed to caffeine in increasing doses (1, 2, and 4 mM). Results In the absence of halothane, resting potential and AP characteristics in MHS and MHN muscles did not differ significantly. Halothane did not alter resting potentials but produced different alterations in the APs in MHS and MHN muscles, whereas the decrease in twitch tension was identical. In contrast to reductions in the AP amplitude and duration in MHN muscle, halothane produced an enlargement of the APs in MHS muscle. The addition of caffeine caused nearly identical prolongations of AP duration in MHS and MHN muscles. Conclusions This in vitro study demonstrates that halothane produces abnormal alterations in the dynamic electric properties of the ventricular excitable membrane from MHS pigs. These results suggest a latent defect in the myocardium of MHS pigs that becomes apparent in the presence of MH-triggering agents.

scholarly journals CNTNAP3 Associated ATG16L1 Expression and Crohn’s Disease

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Yu Qi Qiao ◽  
Mei Lan Huang ◽  
Qing Zheng ◽  
Tian Rong Wang ◽  
An Tao Xu ◽  
...  
Keyword(s):  
Crohn’S Disease ◽  
Crohn's Disease ◽  
Gene Mutations ◽  
In Vitro Study ◽  
Reactive Protein ◽  
Signaling Axis ◽  
Nucleotide Oligomerization ◽  
The Relationship ◽  
Normal Controls

Autophagy is a common physiological process in cell homeostasis and regulation. Autophagy-related gene mutations and autophagy disorders are important in Crohn’s disease (CD). The nucleotide oligomerization domain 2–autophagy genes autophagy 16-like 1 (NOD2–ATG16L1) signaling axis disorder contributes to the dysfunction of autophagy. This paper is focused on the relationship between contactin associated protein-like 3 (CNTNAP3) and ATG16L1 expression in Crohn’s disease. The results indicated that the expression of ATG16L1 is higher in some CD patients compared to normal controls. ATG16L1 was well correlated with the C-reactive protein (CRP) in some CD patients. In vitro study revealed that CNTNAP3 could upregulate the expression of ATG16L1 and increase autophagy vacuoles.

scholarly journals Friction Forces during Sliding of Various Brackets for Malaligned Teeth: An In Vitro Study

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Vito Crincoli ◽  
Letizia Perillo ◽  
Maria Beatrice Di Bisceglie ◽  
Antonio Balsamo ◽  
Vitaliano Serpico ◽  
...  
Keyword(s):  
Friction Force ◽  
In Vitro Study ◽  
Friction Forces ◽  
Orthodontic Wire ◽  
Conventional Brackets ◽  
Frictional Forces ◽  
The Right ◽  
Post Hoc ◽  
Sliding Mechanics

Aims. To measure the friction force generated during sliding mechanics with conventional, self-ligating (Damon 3 mx, Smart Clip, and Time 3) and low-friction (Synergy) brackets using different archwire diameters and ligating systems in the presence of apical and buccal malalignments of the canine.Methods. An experimental setup reproducing the right buccal segment of the maxillary arch was designed to measure the friction force generated at the bracket/wire and wire/ligature interfaces of different brackets. A complete factorial plan was drawn up and a three-way analysis of variance (ANOVA) was carried out to investigate whether the following factors affect the values of friction force: (i) degree of malalignment, (ii) diameter of the orthodontic wire, and (iii) bracket/ligature combination. Tukey post hoc test was also conducted to evaluate any statistically significant differences between the bracket/ligature combinations analyzed.Results. ANOVA showed that all the above factors affect the friction force values. The friction force released during sliding mechanics with conventional brackets is about 5-6times higher than that released with the other investigated brackets. A quasilinear increase of the frictional forces was observed for increasing amounts of apical and buccal malalignments.Conclusion. The Synergy bracket with silicone ligature placed around the inner tie-wings appears to yield the best performance.

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