Transection of anterior mitral basal stay chords alters left ventricular outflow dynamics and wall shear stress.

Background And Aim Of The Study: Anterior mitral basal stay chords are relocated to correct prolapse of the anterior mitral leaflet (AML); it has also been suggested that their transection might be used to treat functional ischemic mitral regurgitation. The study aim was to clarify the effect of stay chord transection (SCT) on the hemodynamic aspects of left ventricular outflow.

Methods: Two three-dimensional left ventricular models including the left ventricular outflow tract and saddle-shaped mitral valve before and after SCT were constructed.

Truly stentless molded autologous pericardial aortic valve prosthesis with single point attached commissures in a sheep model.

Objective: Aortic valve cusp extension and free-hand aortic valve replacement with autologous pericardium has been described. The long-term results were shown to be comparable with commercially available aortic bioprostheses. Nevertheless the relatively demanding surgical technique could not find wide acceptance.

Autologous pericardial pulmonary conduit with single point attached commissures in a sheep model.

Objective: For the surgical treatment of congenital heart disease and in Ross procedure a valved conduit is frequently required. Since homografts are not readily available in every country, a reliable alternative is needed. We developed a novel technique to construct a valved pulmonary conduit with single point attached commissures (SPAC) in a simple and fast way from a small strip of autologous pericardium, molded and briefly treated with glutaraldehyde.

Further information from a sonometric study of the normal tricuspid valve annulus in sheep: geometric changes during the cardiac cycle.

Background And Aim Of The Study: In a previous sono-metric study, changes were described that occurred in the normal tricuspid valve during the cardiac cycle. However, the wealth of data available suggested the need for reporting further findings that should contribute to a better understanding of the dynamics of the tricuspid valve.

Methods: Thirteen sonomicrometry transducers were placed in the hearts of each of seven sheep.

Dimensional ratios of normal mitral valve structures: a tool for determining the degree of geometric distortion in individual patients.

Background And Aim Of The Study: One objective of mitral valve repair is to restore the distorted mitral apparatus geometry to its normal dimensions specific for each patient. Because all dimensions of the normal aortic and mitral valves should be related, it was hypothesized that, in the presence of a normal aortic annulus, it would be possible to determine the dimensions of the structures needed for mitral valve repair.

Methods: In seven sheep, sonometric ultrasound crystals were implanted at the left and right trigones (T1, T2), lateral annulus (P1, P2), and the tips of the anterior and posterior papillary muscles (Ml, M2).

Ventriculo-aortic junction in human root. A geometric approach.

With advances in tissue engineering and improvement of surgical techniques, stentless biological valves and valve-sparing procedures have become alternatives to traditional aortic valve replacement with stented bioprostheses or mechanical valves. New surgical techniques preserve the advantages of native valves but require better understanding of the anatomical structure of the aortic root. Silicone rubber was injected in fresh aortic roots of nine human cadavers under the physiological closing pressure of 80 mmHg.

Forces at single point attached commissures (SPAC) in pericardial aortic valve prosthesis.

Objective: New pericardial aortic bioprostheses (3F Therapeutics and temporarily stented autologous pericardial valve prosthesis) were developed recently. These valves are designed with commissures connected to the aortic wall at only three single points (single point attached commissures (SPAC)). The aim of this study was to investigate the forces acting on SPAC during varying pressure load.

Aortic root dynamics are asymmetric.

Background And Aim Of The Study: The presence of conformational changes in the aortic root during the cardiac cycle is well known, but precise information on time-related changes at each level of the root is lacking.

Methods: High-resolution, 3D sonomicrometry (200 Hz) was applied in an acute sheep model. Twelve crystals were implanted in eight sheep at each base (n = 3), commissure (n = 3), sinotubular junction (n = 3) and ascending aorta (n = 3).

Three-dimensional asymmetrical modeling of the mitral valve: a finite element study with dynamic boundaries.

Background And Aim Of The Study: Previous computational studies of the normal mitral valve have been limited because they assumed symmetrical modeling and artificial boundary conditions. The study aim was to model the mitral valve complex asymmetrically with three-dimensional (3-D) dynamic boundaries obtained from in-vivo experimental data.

Methods: Distance tracings between ultrasound crystals placed in the sheep mitral valve were converted into 3-D coordinates to reconstruct an initial asymmetric mitral model and subsequent dynamic boundary conditions.

Flat or curved pericardial aortic valve cusps: a finite element study.

Background And Aim Of The Study: The finite element method (FEM) has frequently been used to investigate the behavior of the aortic valve, but studies on the performance and behavior of free-hand autologous pericardial aortic valves reconstructed using specially designed valve molds have not been performed. The study aim was to demonstrate the effectiveness of a three-dimensional (3-D) cusp of the authors' design (H-Mold) versus a two-dimensional (2-D) (flat) cusp using a FEM to compare stress distribution and leaflet contact properties.

Methods: Solid models of the aortic root and valve cusps were constructed using a computer-aided design package.

Sonometric study of the normal tricuspid valve annulus in sheep.

Background And Aim Of The Study: Mitral valve dynamic changes during the cardiac cycle have been previously studied in sheep using sonomicrometry. The study aim was to analyze geometric changes of the normal tricuspid annulus in sheep using a similar methodology. This is most likely the first tricuspid valve study using high temporal resolution (200 Hz = 200 data points per second).

Comparison of human and porcine aortic valves.

We compared the anatomy of human and porcine aortic valves. Porcine hearts were collected from the abattoir. Human hearts from patients who had died of non-cardiac causes were examined in the mortuary; only undamaged and anatomically normal hearts were used.

Dynamic balance of the aortomitral junction.

Objective: The aortic and mitral valves have been studied in isolation, as if their functions were independent. We hypothesized that both valves work in synchrony on the basis of the shared myocardial pump and orifice.

Methods: Six sonometric crystals (7 sheep) were placed in both trigones, the midpoint of the anterior and posterior anulus, and the lateral extremities of the posterior anulus.