Treatment of Tricuspid Regurgitation at Subvalvular Level: Hemodynamic and Morphological Assessment in Ex-Vivo Beating Heart Model

ABSTRACTBackground: Functional tricuspid regurgitation (FTR) treatment is challenging and most therapies targeting tricuspid valve (TV) annulus have shown limited durability with high rate of resid..

Statistical Characteristics of Flow Field through Open and Semi-Closed Bileaflet Mechanical Heart Valve

The formation of thrombi on the streamlined surface of the bileaflet mechanical heart valves is one of the main disadvantages of such valves. Thrombi block the valve leaflets and disrupt the cardiovascular system. Diagnosis of thrombosis of the bileaflet mechanical heart valves is relevant and requires the creation of effective diagnostic tools. Hydroacoustic registration of the heart noise is one of the methods for diagnosing the operation of a mechanical heart valve. The purpose of the research is to determine the statistical characteristics of the vortex and jet flow through the open and semi-closed bileaflet mechanical heart valve, to identify hydroacoustic differences and diagnostic signs to determine the operating conditions of the valve. Experimental studies were conducted in laboratory conditions on a model of the left atrium and left ventricle of the heart between which there was the bileaflet mechanical heart valve. Hydrodynamic noise was recorded by miniature pressure sensors, which were located downstream of the valve. The vortex and jet flow behind the prosthetic heart valve were non-linear, random processes and were analyzed using the methods of mathematical statistics and probability theory. The integral and spectral characteristics of the pressure field were obtained and the differences in the noise levels and their spectral components near the central and side jets for the open and semi-closed mitral valve were established. It was shown that hydroacoustic measurements could be an effective basis for developing diagnostic equipment for monitoring the bileaflet mechanical heart valve operation. Doi: 10.28991/SciMedJ-2020-0204-1 Full Text: PD

Transcatheter Edge-to-Edge Treatment of Functional Tricuspid Regurgitation in an Ex Vivo Pulsatile Heart Model

Although associated with left heart pathologies, functional tricuspid regurgitation (FTR) is often left untreated during left heart surgery. Hence, owing to its degenerative character, reoperation is often needed, encompassing an impressive (25% to 35%) mortality rate. Thus transcatheter approaches to FTR are raising great interest

Effect of Fluid Viscosity on Noise of Bileaflet Prosthetic Heart Valve

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Leaflet kinematics after the Yacoub and Florida-sleeve operations: results of an in vitro study

The Florida-sleeve is a valve-sparing technique that causes minimal interference to leaflet kinematics and aortic root dynamism. The aim of this in vitro study was to evaluate the effects of the Florida-sleeve and Yacoub techniques on aortic leaflet kinematics

Long-arm Clip for Transcatheter Edge-to-Edge Treatment of Mitral and Tricuspid Regurgitation – Ex-Vivo Beating Heart Study

Background: A longer-arm clip design for transcatheter edge-to-edge repair of mitral and tricuspid valves could be beneficial in treating complex valve pathologies. Its hemodynamic effects and usability are unknown. This study aims to assess its new design in an ex-vivo beating heart model. Methods: The long-arm clip was implanted in porcine left (n = 14) and right (n = 6) hearts with induced degenerative mitral regurgitation and functional tricuspid regurgitation, respectively. Hemodynamic conditions were assessed at baseline, pathology and post-treatment. Usability and grasping quality were evaluated during simulated treatment. Results: Mitral valve treatment significantly increased cardiac output (p < 0.001) and decreased mean left atrial pressure during ventricular systole (p = 0.001) with respect to pathological conditions. Tricuspid treatment with grasping involving septal leaflet significantly increased cardiac output (posterior-septal grasping: p = 0.006; anterior-septal grasping: p = 0.04). There was no significant increase of transvalvular gradient pressure nor tissue damage. Conclusion: Long-arm clip treatment was feasible in porcine hearts, it effectively reduced regurgitation and did not significantly increase the transvalvular pressure gradient

A novel system for the treatment of aortic annular dilation: an ex vivo investigation

OBJECTIVES: The main reason for aortic repair failures is recurrent annular dilatation. The fibrous portion of left ventricular outflow tract dilates. A novel device was designed to tackle this problem. METHODS: The device consists of an internal ring applied at the aortic annulus plus an external flexible band at the level of the aortic root. The internal ring has a semi-rigid portion (40%, placed at ventriculo-arterial junction) and a flexible portion to allow it to conform along the curves of the non-coronary/right coronary leaflet and right coronary/left coronary leaflet commissures. The external band acts as a reinforcement to the internal ring. A pulsatile mock loop capable of housing porcine aortic valve was used. Working conditions were 60 bpm of heart rate, 75 of stroke volumes and 120-80mmHg of simulated pressure. Mean gradient, effective orifice area, annular diameter, coaptation height and length were recorded on 11 aortic root units (ARUs). High-speed video and standard echocardiographic images were also recorded. All data were acquired in the following conditions: (i) basal (untreated ARU); (ii) pathological condition (left coronary/non-coronary triangle was dilated by suturing an aortic patch); and (iii) ARU treated with the device. RESULTS: Gradients and effective orifice area were respectively 0.9 \ub1 0.64mmHg and 3.1 \ub1 0.7cm2 (pathological) and 3.7 \ub1 1.1mmHg and 1.5 \ub1 0.2cm2 (treated, P < 0.05). Left coronary/non-coronary diameter decreased from 2.4 \ub1 0.2 cm (pathological) to 2.0 \ub1 0.2 (treated, P < 0.05). Coaptation length and height were fully restored to basal values following treatment. Visual inspection showed proper dynamics of the leaflet, confirmed by high-speed video and echocardiography. CONCLUSIONS: The device allowed for restoring physiologic-like coaptation in the experimental model, without inducing clinically relevant worsening of the haemodynamics of the treated ARU

Design of a simple coronary impedance simulator for the in vitro study of the complex coronary hemodynamics

Several novel approaches were recently developed to treat aortic root pathologies. The alteration induced by some of these approaches to the biomechanics of the aortic root could possibly affect the coronary perfusion, compromising the procedural outcome. In this scenario, the need to replicate in vitro the coronary flow pattern in physiological and pathological conditions is becoming crucial for the functional assessment of novel devices and techniques. This article describes the design of an easy-to-use, left-and-right coronary impedance simulator, coupled with native aortic roots for in vitro pulsatile tests. Experiments were performed in order to assess the performances of the coronary impedance simulator when coupled with healthy aortic valves (cardiac output: 3.8  ±  0.26 l min(-1); mean systemic pressure: 95  ±  1.3 mmHg; mean coronary flow rate: 272  ±  13.4 ml min(-1)) or with regurgitant valves (cardiac output: 1.9  ±  0.24 l min(-1); mean systemic pressure of 45  ±  3.3 mmHg; mean coronary flow rate:149  ±  21.9 ml min(-1)). The acute systemic response to valve regurgitation was also replicated, with increased beat rate and afterload, aimed at restoring the systemic pressure (cardiac output: 2.5  ±  0.23 l min(-1); mean systemic pressure of 109  ±  6.1 mmHg; mean coronary flow rate: 262  ±  35.5 ml min(-1)). In the test conditions, the system was able to replicate in vitro the main determinants of the coronary circulation with physiological left/right coronary flow rate repartition, and a realistic interaction between coronary and systemic hemodynamics. The coronary simulator appears to be a suitable platform to study and optimize the interactions between novel approaches to aortic valve pathology and the coronary perfusion

TCT-17 Tricuspid Valve Regurgitation Reduction Following Concomitant Subvalvular and Annulus-level Treatment – Ex-vivo Study

En este artículo analizamos uno de los personajes y de los momentos de mayor grandeza realizados por el gran Francisco Pizarro; su vida, sus heroicos hechos en América y en especial en Perú, y de su final. Destacando el valor de aquel extremeño sin par y de su conquista del Imperio Inca, visto a través de las crónicas coetáneas y de los principales personajes que colaboraron en tales hechos.In this article we analyse one of the characters and the glorious actions carried out by the great Francisco Pizarro; his life, his heroic deeds in America and especially in Peru and his tragic end. We will emphasize the courage of that inhabitant of Extremadura and his conquest of the Inca empire, analysed through the contemporary chronicles and those main characters who intervened in such events.peerReviewe