Abstract:
A mechanical prosthetic heart valve having a ring, multiple hinges, and multiple leaflets. The hinges are attached to the ring and are evenly spaced from one another along the inner circumference of the ring. Each leaflet is rotably attached to a hinge by an opening located in the center of the lower portion of the leaflets. The ring can include multiple protrusions located along the inner circumference of the ring. The protrusions of the ring limit the opening angle of the leaflets. By limiting the opening angle of the leaflets, wear and tear of the hinges and leaflets, as well as the probability of malfunction of the mechanical prosthetic heart valve are reduced. In addition, limiting the opening angle of the leaflets may increase the opening and closing speed of the leaflets, thus improving performance of the mechanical prosthetic heart valve when the patient is experiencing an elevated cardiac frequency.

Description:
BACKGROUND 
       [0001]    1. Field of Art 
         [0002]    The disclosure generally relates to the field of prosthetic heart valves, and more specifically to trileaflet mechanical prosthetic heart valves. 
         [0003]    2. Description of the Related Art 
         [0004]    When one of the valves inside a patient&#39;s heart does not work properly, the heart valve may be replaced with a prosthetic valve. Heart valve diseases may be classified into two different categories: regurgitation and stenosis. Regurgitation, or backflow, occurs if a valve doesn&#39;t close tightly. Blood leaks back into the chambers rather than flowing forward through the heart or into an artery. Stenosis occurs if the flaps of a valve thicken, stiffen, or fuse together. This prevents the heart valve from fully opening. As a result, not enough blood flows through the valve. 
         [0005]    Prosthetic heart valves can be categorized into two main categories: mechanical prosthetic heart valves, and tissue or bio-prosthetic heart valves. Mechanical prosthetic heart valves are durable and may last throughout the remainder of the patient&#39;s lifetime. Currently existing mechanical prosthetic heart valves do not mimic a human natural heart valve shape. Even in the fully opened position, leaflets may partially block the passage of blood through the valve causing turbulence in the blood. The increased turbulence in the blood increases the probability of coagulation of the blood near the regions of high turbulence around the mechanical prosthetic heart valve. Patients with mechanical prosthetic heart valves oftentimes take anticoagulants and/or blood thinners to prevent blood clots from forming and causing a malfunction of the mechanical prosthetic heart valve and/or turning into an embolism. In addition, the opening and closing of the leaflets causes wear and tear near the interface between the leaflets and the hinges to which the leaflets are attached. The leaflets may also be susceptible to being stuck in the opened position if the leaflets open past a threshold angle which causes the backwards blood flow to push the leaflets on the wrong side, holding the leaflets in the opened position instead of pushing the leaflets to rotate to the closed position. 
         [0006]    Tissue valves are made from valves of an animal donor or another animal tissue that is strong and flexible. Tissue valves can last 10 to 20 years and patients with prosthetic tissue heart valves do not need to take anticoagulants or blood thinners. The likelihood of a prosthetic tissue heart valve to malfunction later in the patient&#39;s life due to wear and tear is higher than of mechanical prosthetic heart valves, and thus, patients with prosthetic tissue heart valves may additionally have a second heart surgery to replace the prosthetic tissue heart valve. 
       SUMMARY 
       [0007]    Disclosed is a mechanical prosthetic heart valve having a ring, multiple hinges and multiple leaflets. For example the valve can include a ring with three hinges and three leaflets to form a trileaflet mechanical prosthetic heart valve. This trileaflet design mimic&#39;s the natural human heart valve shape and functions in a similar way to the natural human valve. The ring of the heart valve can include multiple protrusions located along an inner circumference of the ring that prevent the leaflets from opening beyond a certain point, thus avoiding the possibility of the backwards blood flow being able to hold the leaflets in an open position. For instance, a trileaflet mechanical prosthetic heart valve includes three protrusions located along an inner circumference of the ring. The hinges are attached to the ring and are evenly spaced from one another along the inner circumference of the ring. Each leaflet is attached to one of the hinges by an opening located in the center of the lower portion of the leaflets. The hinges can be positioned in the middle of each leaflet allowing the leaflets to swing open and closed along the hinges, and maximizing freedom of movement of the leaflets since each has its own hinge to rotate around. The position of the hinges and the leaflets relative to the ring is such that the leaflets are immediately adjacent to the ring when open and any blockage of the blood flow through the valve by the leaflets is minimized, as well as minimizing turbulence in the blood flow. The leaflets have a unique shape and curvature such that, when open, they generally mimic the shape of the ring, further limiting their interference with the blood flow. 
         [0008]    In some embodiments, the mechanical prosthetic heart valve is covered by a bio-hemo-compatible material. Furthermore, the ring, the hinges, and the leaflets may be composed of titanium, or other materials. In some embodiments, the ring, hinges, and leaflets are composed of titanium coated with a layer of a bio-hemo-compatible material, such as, titanium oxide. 
         [0009]    The protrusions of the ring prevent the leaflets from forming an angle that is greater than 90° with respect to the transversal plane of the ring. Since the leaflets cannot open to greater than 90°, it is not possible for the blood to flow against the leaflets on the wrong side of the leaflets such that they are held in an open position and prevented from closing. Instead, the leaflets rotate open as blood flows through the valve and immediately rotate back to the closed position afterwards to prevent backflow. By limiting the opening angle of the leaflets, wear and tear of the hinges and leaflets, as well as the probability of malfunction of the mechanical prosthetic heart valve are reduced. In addition, limiting the opening angle of the leaflets may increase the opening and closing speed of the leaflets, thus improving performance of the mechanical prosthetic heart valve when the patient is experiencing an elevated cardiac frequency. The protrusions of the ring may be evenly spaced relative to each other along the inner circumference of the ring. For instance, the protrusions may be located on an upper portion of the hinges. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0010]    The disclosed embodiments have other advantages and features which will be more readily apparent from the detailed description, the appended claims, and the accompanying figures (or drawings). A brief introduction of the figures is below. 
           [0011]    Figure ( FIG. 1  illustrates a human heart. 
           [0012]      FIG. 2A  illustrates a conventional mechanical prosthetic heart valve  200  with leaflets  220  in an opened position. 
           [0013]      FIG. 2B  illustrates a conventional mechanical prosthetic heart valve  200  with leaflets  220  in a closed position. 
           [0014]      FIG. 3A  illustrates a trileaflet mechanical prosthetic heart valve with leaflets in an opened position, according to one embodiment. 
           [0015]      FIG. 3B  illustrates the trileaflet mechanical prosthetic heart valve with leaflets in a closed position, according to one embodiment. 
           [0016]      FIG. 3C  illustrates a top view of the trileaflet mechanical prosthetic heart valve with leaflets in an opened position, according to one embodiment. 
           [0017]      FIG. 3D  illustrates a top view of the trileaflet mechanical prosthetic heart valve with leaflets in the closed positions, according to one embodiment. 
           [0018]      FIG. 4A  illustrates a side view of a leaflet of the trileaflet mechanical prosthetic heart valve, according to one embodiment. 
           [0019]      FIG. 4B  illustrates a front view of the leaflet of the trileaflet mechanical prosthetic heart valve, according to one embodiment. 
           [0020]      FIG. 4C  illustrates a top view of the leaflet of the trileaflet mechanical prosthetic heart valve, according to one embodiment. 
           [0021]      FIG. 4D  illustrates a perspective view of the leaflet of the trileaflet mechanical prosthetic heart valve, according to one embodiment. 
           [0022]      FIG. 4E  illustrates a side view of a leaflet  320  of the trileaflet mechanical prosthetic heart valve  300  showing the dimensions of the leaflet  320 , according to one embodiment. 
           [0023]      FIG. 4F  illustrates a front view of the leaflet  320  of the trileaflet mechanical prosthetic heart valve  300  showing the dimensions of the leaflet  320 , according to one embodiment. 
           [0024]      FIG. 4G  illustrates a top view of the leaflet  320  of the trileaflet mechanical prosthetic heart valve  300  showing the dimensions of the leaflet  320 , according to one embodiment. 
           [0025]      FIG. 4H  illustrates an auxiliary view of the leaflet  320  of the trileaflet mechanical prosthetic heart valve  300  showing the dimensions of the leaflet  320 , according to one embodiment. 
           [0026]      FIG. 5A  illustrates a side view of a portion of a trileaflet mechanical prosthetic heart valve with leaflets in the opened position, according to one embodiment. 
           [0027]      FIG. 5B  illustrates a side view of a portion of a trileaflet mechanical prosthetic heart valve with leaflets in the closed position, according to one embodiment. 
           [0028]      FIG. 6A  illustrates a side view of a portion of a trileaflet mechanical prosthetic heart valve without a leaflet stopper and with leaflets in the opened position, according to one embodiment. 
           [0029]      FIG. 6B  illustrates a side view of a portion of a trileaflet mechanical prosthetic heart valve without a leaflet stopper and with leaflets in the closed position, according to one embodiment. 
           [0030]      FIG. 7  is a flow chart illustrating a method of operation of a trileaflet mechanical prosthetic heart valve, according to one embodiment. 
       
    
    
     DETAILED DESCRIPTION 
       [0031]    The Figures (FIGS.) and the following description relate to preferred embodiments by way of illustration only. It should be noted that from the following discussion, alternative embodiments of the structures and methods disclosed herein will be readily recognized as viable alternatives that may be employed without departing from the principles of what is claimed. 
         [0032]    Reference will now be made in detail to several embodiments, examples of which are illustrated in the accompanying figures. It is noted that wherever practicable similar or like reference numbers may be used in the figures and may indicate similar or like functionality. The figures depict embodiments of the disclosed system (or method) for purposes of illustration only. One skilled in the art will readily recognize from the following description that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles described herein. 
       The Human Heart 
       [0033]      FIG. 1  illustrates the human heart. The human heart is divided into four chambers. The left atrium  110 , the right atrium,  120 , the left ventricle  130 , and the right ventricle  140 . The heart further includes multiple valves that allow the flow of blood in one direction, and block the flow of blood in the opposite direction. 
         [0034]    For instance, during ventricular diastole, blood from the pulmonary veins  160  enters the left atrium  110  and continues flowing through the mitral valve  150 A into the left ventricle  130 . Similarly, blood from the superior vena cava  170 A and the inferior vena cava  170 B enters the right atrium  120  and continues flowing through the tricuspid valve  150 B into the right ventricle. During the ventricular diastole, the aortic valve  150 C prevents blood from the aorta  180  to flow back into the left ventricle  130 , and the pulmonary valve  150 D prevents blood from the pulmonary artery  190  to flow back into the right ventricle  140 . 
         [0035]    During ventricular systole, blood from the left ventricle  130  flows out of the heart  100  into the aorta  180  through the aortic valve  150 C and blood from the right ventricle  140  flows out of the heart  100  into the pulmonary artery  190  through the pulmonary valve  150 D. During ventricular systole, the mitral valve  150 A prevents blood from the left ventricle from flowing back into the left atrium  110 , and the tricuspid valve  150 B prevents blood from the right ventricle from flowing back into the right atrium  120 . 
         [0036]    During the lifetime of a person, the valves  150  of the heart may deteriorate or become defective. For instance, a heart valve  150  may not be able to fully open due to stiff or fused leaflets (valvular stenosis). In this case, a narrowed opening of the heart valve  150  may cause the heart work harder than a heart with a normal valve to allow blood flow through the defective heart valve. Additionally, a heart valve  150  may be unable to fully close, allowing some of the blood to leak backwards across the valve (valvular insufficiency). In this case, the leak in the heart valve  150  may cause the heart to work harder to compensate for the backward blood flow. 
         [0037]    To treat a patient with a deteriorated or defective heart valve, a prosthetic heart valve may be used to replace the deteriorated or defective heart valve. 
         [0038]      FIG. 2A  illustrates a conventional mechanical prosthetic heart valve  200  with leaflets  220  in an opened position; and  FIG. 2B  illustrates a conventional mechanical prosthetic heart valve  200  with leaflets  220  in a closed position. The conventional mechanical prosthetic heart valve  200  includes a ring  210  and two leaflets  220 . When the leaflets  220  of the prosthetic heart valve  220  are in the opened position, blood may flow from a first side  250 A of the heart valve  200  to a second side  250 B of the heart valve  200 . As illustrated in  FIG. 2A , blood may flow through an opening between leaflet  220 A and ring  210 , an opening between leaflet  220 A and leaflet  220 B, or an opening between leaflet  220 B and ring  210 . This increases the amount of turbulence in the blood flow increasing the probability of thrombogenicity and hemolysis. The same is true of any prior design in which a portion of the leaflets sits within the blood flow path, as opposed to being positioned closely to the ring such that a minimal portion of each leaflet is in the blood flow path. 
       Trileaflet Mechanical Prosthetic Heart Valve 
       [0039]      FIGS. 3A-3D  illustrate a trileaflet mechanical prosthetic heart valve, according to some embodiments.  FIG. 3A  illustrates a trileaflet mechanical prosthetic heart valve  300  with leaflets  320  in an opened position;  FIG. 3B  illustrates the trileaflet mechanical prosthetic heart valve  300  with leaflets  320  in a closed position;  FIG. 3C  illustrates a top view of the trileaflet mechanical prosthetic heart valve  300  with leaflets  300  in the opened position; and  FIG. 3D  illustrates a top view of the trileaflet mechanical prosthetic heart valve  300  with leaflets  320  in the closed position, according to one embodiment. 
         [0040]    The trileaflet mechanical heart valve  300  includes a ring  310 , three leaflets  320  ( 320 A,  320 B,  320 C), and three hinges  330  ( 330 A,  330 B,  330 C). In some embodiments, a mechanical prosthetic heart valve may include additional leaflets and hinges. The hinges  330  rotably attach the leaflets  320  to the ring  310 . The hinges  330  are configured such that each leaflet  320  opens and closes by sliding along the hinges at an opening located at the central lower portion of the leaflet  320 . Each hinge  330  may include an open area  340  in the middle of the hinge where protuberances  345  located at the sides of the opening of the central lower portion of the leaflets attach to the hinge  330 . In some embodiments, the leaflets  320  are slidable along the hinge. The leaflets  320  are configured to open as shown in  FIG. 3A  and  FIG. 3C  to allow the flow of blood from a first side  350 A of the heart valve to a second side  350 B of the heart valve. Furthermore, the leaflets  320  are configured to close as shown in  FIG. 3B  and  FIG. 3D  to block the backward blood flow from the second side  350 B of the heart valve to the first side  350 A of the heart valve. 
         [0041]      FIG. 4A  illustrates a side view of a leaflet  320  of the trileaflet mechanical prosthetic heart valve  300 ;  FIG. 4B  illustrates a front view of the leaflet  320  of the trileaflet mechanical prosthetic heart valve  300 ;  FIG. 4C  illustrates a top view of the leaflet of the trileaflet mechanical prosthetic heart valve; and  FIG. 4D  illustrates a perspective view of the leaflet of the trileaflet mechanical prosthetic heart valve, according to one embodiment. Leaflet  320  has a generally triangular shape. Furthermore, leaflet  320  is flat in the longitudinal axis and concave-convex in the transversal axis. In some embodiments, the leaflets are cut from a cylindrical piece. As such, as shown in  FIGS. 3A and 3C , when the leaflets  320  are in the opened position, the outer contour of the leaflets  320  substantially tracks the inner contour of the ring  310  of the heart valve  300 . Thus, this increases the effective opening area of the heart valve  300 , and allows for a better laminar flow and reduction of the turbulence of the blood passing through the heart valve  300 . In some embodiments, the distance between each leaflet and the ring when the leaflets are open (D L-R ) is no more than 1 mm at any point around the circumference of the ring. 
         [0042]    The improved laminar flow of heart valve  300  reduces the probability of thrombogenicity and hemolysis thus, reducing the need of a patient using the prosthetic mechanical heart valve  300  of taking anticoagulants. 
         [0043]    The bottom portion of the leaflet  320  has a curved shape that substantially tracks the inner contour of the ring  310  of the heart valve  300  when the leaflets are in the closed position. Additionally, the bottom portion of the leaflet  320  includes an opening  410  for coupling the leaflet  320  to the hinge  330 . The leaflet  320  additionally includes at least two protuberances  420  along the sides of the opening  410  guide the movement of the leaflets. In one embodiment, the protuberances  420  form a first portion of the opening  410  above the protuberance and a second portion of the opening  410  between the protuberances. The first portion of the opening  410  is wider than the second portion of the opening  410 . In some embodiments, the opening  410  includes a third portion below the protuberances  420  that is wider than the second portion of the opening  410 . The third portion of the opening  410  may be configured to engage and slide over the hinge during the opening of the leaflet  320 . 
         [0044]    The leaflet  320  is coupled to the ring  310  from a single point located at the center of the transversal axis of the leaflet  320 . This prevents the leaflet from separating from the ring  310  during the opening of the leaflet increasing the size of the central opening of the heart valve  300  and reducing the amount of blood that passes thought the valve from the opening between the leaflet  320  and the ring  310 . As such, turbulence of the blood passing through the heart valve  300  is reduced, thus reducing the probability of thrombogenicity and hemolysis. 
         [0045]    For fluid dynamics reasons, leaflets  320  further include a flat region  430 . Flat regions  430  are located on the left end and the right end of the leaflet  320 . 
         [0046]      FIG. 4E  illustrates a side view of a leaflet  320  of the trileaflet mechanical prosthetic heart valve  300  showing the dimensions of the leaflet  320 ;  FIG. 4F  illustrates a front view of the leaflet  320  showing the dimensions of the leaflet  320 ;  FIG. 4G  illustrates a top view of the leaflet  320  showing the dimensions of the leaflet  320 ; and  FIG. 4H  illustrates an auxiliary view of the leaflet  320  across the AA plane shown in  FIG. 4E  showing the dimensions of the leaflet  320 , according to one embodiment. The leaflet  320  has a height of 16.49 mm and a width of 19.95 mm. The leaflet  320  has a closing angle of 35°. Opening  410  has a width of 2 mm, and protuberances  420  have a radius of 1.5 mm. The leaflets further have an outer radius of 12 mm and an inner radius of 11 mm. 
         [0047]    The size of the leaflet shown in  FIG. 4E-4H  is exemplary for replacing the aortic valve of an adult with an average size heart, and may be scaled up or down depending on the many factors including the size of the heart of the patient, and the heart valve being replaced by the trileaflet mechanical prosthetic heart valve  300 . For instance, the leaflets used for a mitral valve of an adult with an average size heart may be scaled up or down compared to the leaflets shown in  FIG. 4E-4H . 
         [0048]      FIG. 5A  illustrates a side view of a portion of the trileaflet mechanical prosthetic heart valve  300  with a leaflet  320  in the opened position; and  FIG. 5B  illustrates a side of the trileaflet mechanical prosthetic heart valve  300  with the leaflet  320  in the closed position. As illustrated in  FIG. 5A , when the leaflets are in the opened position, the leaflets form an angle substantially perpendicular to the transverse plane (R Y -R X  plane) of the ring  310 . As illustrated in  FIG. 5B , when the leaflets are in the closed position, the longitudinal plane of the leaflets  320  form an angle larger than 0° with the transverse plane of the ring  310 . In some embodiments, the longitudinal plane (L Z -L X  plane) of the leaflets  320  may form an angle (δ L-R ) larger 35° with the transverse plane of the ring  310 . This reduces the swing or trajectory of the leaflets from the closed position to the opened position and vice versa, reducing the amount of time for the heart valve  300  to open and close. As such, the trileaflet mechanical prosthetic heart valve  300  may function properly even when the patient is experiencing an elevated cardiac frequency. 
         [0049]    In one embodiment, the ring  310  includes stoppers  510  that prevent the leaflets  320  from opening beyond a certain angle. For instance, stoppers  510  prevent the leaflets  320  from opening beyond 90° with respect to the transversal plane of the ring  310  (i.e., stoppers  510  prevent δ L-R  from exceeding 90°). Preventing the leaflets  320  from opening beyond 90° with respect to the transversal plane of the ring  310  reduces the turbulence of the blood caused by the leaflets  320 , and reduces the swing or trajectory of the leaflets  320  during the closing and opening of the heart valve  320  (thus reducing the closing and opening time of the heart valve  300 , and the wear and tear of the leaflets  320 ), and reduces the probability of a leaflet from being stuck in the opened position. For example, backflow of blood in the wrong direction in the valve could potentially create a force against the leaflet to hold the leaflet in the open position if the leaflet is allowed to open beyond 90° with respect to the transversal plane of the ring  310 .  FIGS. 5A and 5B  show one example of the stoppers  510 . The stoppers can be otherwise positioned on the ring or shaped differently. For example, the stoppers can be positioned directly above the hinge at the top of the ring or in the middle of the ring. As another example, there can be a stopper positioned on the hinge to stop the lower portion of the leaflet from moving away from the ring beyond a point that positions the ring at 90° with respect to the transversal plane of the ring. 
         [0050]      FIGS. 5A and 5B  also illustrate an open area  505  of the hinge  330 . The hinge attaches at either end around to the ring to form the open area  505 . The open area  505  is shown as circular in the figures, but it can be otherwise shaped. The protuberances  420  (shown in  FIG. 4B ) of the leaflets protrude into this open area  505  of the hinge  330 , as is generally visible in  FIGS. 3A and 3B . These protuberances ensure the leaflets remain attached to the valve even though the leaflets are open below the protuberances, as shown in  FIG. 4B . The wider portion (or first portion) of the opening  410  of the leaflet (above the narrower portion or second portion into which the protuberances protrude, as shown in  FIG. 4B ), engages the hinge and allows the leaflet to slide freely along the hinge to rotate open or closed. The lower wider portion (or third portion) below the protuberances is open to the base of the leaflet. This lower wide portion that is open to the leaflet base allows the leaflet to open by sliding over an engaging the hinge. When the leaflet is closed, this lower portion is generally aligned with the open area  505  of the hinge, but as the leaflet opens, this lower portion slides over one end of the hinge on either side of the hinge, allowing the leaflet to open freely. 
         [0051]      FIG. 6A  illustrates a side view of a portion of a trileaflet mechanical prosthetic heart valve without a leaflet stopper, with leaflets in the opened position; and  FIG. 6B  illustrates a side view of the portion of the trileaflet mechanical prosthetic heart valve without a leaflet stopper, with leaflets in the closed position, according to one embodiment. The leaflets  320  of the heart valve without stoppers  510 , when closed, are positioned similarly to the leaflets  320  of the heart valve with stoppers  510 . Conversely, when the leaflets  320  are in the opened position, the leaflets  320  may be positioned at an angle larger than 90° with respect to the transversal plane of the ring  310 . 
         [0052]    Since each leaflet  320  is independently attached to the ring through an independent hinge  330 , each leaflet may open and close independently of the other leaflets. Thus, if the movement of a leaflet is partially or completely limited (i.e., a leaflet may not completely open or close), the other two leaflets may continue functioning properly, reducing the probability of an acute deterioration of the patients health. 
         [0053]    In some embodiments, the ring  310 , leaflets  320 , and hinges  330  are composed of a metallic material. For instance, the ring  310 , leaflets  320 , and hinges  330  may be composed of titanium or a combination of titanium with titanium oxide or a combination of titanium with other materials. Further, the trileaflet mechanical prosthetic heart valve  300  may be covered with a bio-hemo-compatible material (e.g., titanium oxide). 
         [0054]    Moreover, the trileaflet mechanical prosthetic heart valve  300  may be used as a prosthetic implant for replacement of any of the four natural heart valves in humans, in case of dysfunction, congenital defects, or acquired complications. The replacement of a human heart valve with the trileaflet mechanical prosthetic heart valve  300  may be performed by a surgical procedure at open heart. Furthermore, the trileaflet mechanical prosthetic heart valve  300  may be used in blood pumps, devices for partial circulatory support, in heart prosthesis completely implantable or of external use, and can also be used in vascular conducts made of biological or synthetic material used surgery of large conducts, such as the ascendant aorta and pulmonary trunk. 
       Method of Operation of Trileaflet Mechanical Prosthetic Heart Valve 
       [0055]    In use, the heart valve, such as the trileaflet mechanical prosthetic heart valve described above, operates similarly to a natural human heart valve. Initially, the leaflets of the valve can sit in a closed position, as shown in  FIGS. 3B and 3D . The leaflets, when closed, may be positioned at approximately 35° with respect to the transversal plane of the ring, as shown in  FIG. 3B . As the heart muscles contract, blood is advanced within the heart from one chamber to another or between chambers and blood vessels in the direction shown in  FIG. 3A . The muscle contraction causes the blood to put pressure on the valve in the direction shown in  FIG. 3A  to push the leaflets open. As the valve receives  700  pressure due to the blood flow, the leaflets each swing along their individual hinges into an open position. Specifically, the opening of the leaflets allows the upper portion of the leaflet opening to slide  705  along the hinge toward the ring, with the upper wider portion of the opening generally surrounding the arm of the hinge and with the protuberances protruding into the open area of the hinge. The protuberances ensure that the leaflet does not disengage from the hinge during opening and closing. As the leaflet continues to open, the lower wider portion of the leaflet opening slides  705  over the hinge on either side of the hinge to allow the base of the leaflet move along the hinge, moving the lower portion of the opening away from the ring. 
         [0056]    Where the valve includes protrusions or another stopping mechanism, the leaflets swing open until they contact  710  the protrusions/stopping mechanism, which prevents the leaflets from opening beyond a specified point. For example, the leaflets may be prevented from opening more than 90° with respect to the transversal plane of the ring. In one embodiment, the leaflets, when closed, are positioned at approximately 90° with respect to the transversal plane of the ring, as shown in  FIGS. 3A and 3C . 
         [0057]    The curvature of the leaflets closely matches the curvature of the ring, as shown in  FIG. 3C , so valve has a very low profile when the leaflets are open, minimizing blood flow blockage and turbulence. The leaflets will stay in the open position as the blood flows through from chamber to chamber or between vessel and chamber. Once the blood has passed through the valve, the blood puts reverse pressure on the leaflets in the opposite direction of that shown in  FIG. 3A . This receiving  715  of backward pressure causes the leaflets to swing closed. The leaflets each rotate long their individual hinge to slide into a closed position, returning to the position of  FIGS. 3B and 3D . Specifically, the lower portion of the opening of the leaflet slides  720  on either side of the hinge closer to the ring and the upper portion of the opening slides  720  along the hinge away from the ring. The leaflets will remain closed until the next contraction of the heart muscles causes blood to again flow through the valve. 
       Additional Configuration Considerations 
       [0058]    Throughout this specification, plural instances may implement components, operations, or structures described as a single instance. Structures and functionality presented as separate components in example configurations may be implemented as a combined structure or component. Similarly, structures and functionality presented as a single component may be implemented as separate components. These and other variations, modifications, additions, and improvements fall within the scope of the subject matter herein. 
         [0059]    As used herein any reference to “one embodiment” or “an embodiment” means that a particular element, feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. The appearances of the phrase “in one embodiment” in various places in the specification are not necessarily all referring to the same embodiment. 
         [0060]    As used herein, the terms “comprises,” “comprising,” “includes,” “including,” “has,” “having” or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a process, method, article, or apparatus that comprises a list of elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Further, unless expressly stated to the contrary, “or” refers to an inclusive or and not to an exclusive or. For example, a condition A or B is satisfied by any one of the following: A is true (or present) and B is false (or not present), A is false (or not present) and B is true (or present), and both A and B are true (or present). 
         [0061]    In addition, use of the “a” or “an” are employed to describe elements and components of the embodiments herein. This is done merely for convenience and to give a general sense of the invention. This description should be read to include one or at least one and the singular also includes the plural unless it is obvious that it is meant otherwise. 
         [0062]    Upon reading this disclosure, those of skill in the art will appreciate still additional alternative structural and functional designs for a system and a process for trileaflet mechanical prosthetic heart valve through the disclosed principles herein. Thus, while particular embodiments and applications have been illustrated and described, it is to be understood that the disclosed embodiments are not limited to the precise construction and components disclosed herein. Various modifications, changes and variations, which will be apparent to those skilled in the art, may be made in the arrangement, operation and details of the method and apparatus disclosed herein without departing from the spirit and scope defined in the appended claims.