1. Field of the Invention
The present invention relates generally to a device for fixturing a prosthesis to a first mass and methods of making and using the same.
2. Description of the Related Art
Prosthetic heart valves can replace defective human valves in patients. Prosthetic valves commonly include sewing rings or suture cuffs or rings that are attached to and extend around the outer circumference of the prosthetic valve orifice.
In a typical prosthetic valve implantation procedure, the aorta is incised and the defective valve is removed leaving the desired placement site that may include a fibrous tissue layer or annular tissue. Known heart valve replacement techniques include individually passing sutures through the fibrous tissue or desired placement site within the valve annulus to form an array of sutures. Free ends of the sutures are extended out of the thoracic cavity and laid, spaced apart, on the patient's body. The free ends of the sutures are then individually threaded through a flange of the sewing ring. Once all sutures have been run through the sewing ring (typically 12 to 18 sutures), all the sutures are pulled up taught and the prosthetic valve is slid or “parachuted” down into place adjacent the placement site tissue. The prosthetic valve is then secured in place by traditional knot tying with the sutures. This procedure is time consuming as doctors often use three to ten knots per suture.
The sewing ring is often made of a biocompatible fabric through which a needle and suture can pass. The prosthetic valves are typically attached to the sewing rings which are sutured to a biological mass that is left when the surgeon removes the existing valve from the patient's heart. The sutures are tied snugly, thereby securing the sewing ring to the biological mass and, in turn, the prosthetic valve to the heart.
FIG. 1 illustrates a valve prosthesis 2 fixed to a vessel 4 with sutures 6. The vessel 4 has a supra-annular space 8, an intra-annular or trans-annular space 10 and an infra-annular space 12. The natural valve that existed in the vessel has been removed. The placement site of the valve prosthesis 2 can be in the supra-annular space 8, an intra-annular or trans-annular space 10. The placement site is limited to being inferior to, and therefore not blocking, openings of the coronary arteries and superior to a plane defined by the insertion of the anterior leaflet of the mitral valve and the highest portion of the intraventricular septum. In the example shown in FIG. 1, the valve prosthesis 2 is on the shoulder between the supra-annular and trans-annular spaces 8 and 10. The valve prosthesis 2 has a sewing cuff or ring 14 that presses or rests against the supra-annular vessel wall.
FIG. 1 also illustrates two common types of suturing. On the left, the suture 6 can be fed into the vessel wall in the trans-annular or infra-annular space 10 or 12. The trailing end of the suture 6 can be secured to a pledget 16 by a knot 18 in the suture 6 behind the pledget 16. As illustrated in FIG. 2, the suture assembly consists of two curved needles 400 attached by a common length of suture 6. A pledget 16 is typically preloaded onto the suture 6. The pledget 16 braces the trailing end of the suture loop 6 against the vessel wall. The suture 6 then feeds through the vessel wall and exits the vessel wall in the supra-annular space 8. The surgeon passes the suture 6 through the sewing ring 14 and ties a knot 18 behind the sewing ring 14 to secure the sewing ring 14 to the vessel wall.
On the right side of FIG. 1, the suture 6 feeds into the vessel wall in the supra-annular space 8. The suture 6 is then attached to the pledget 16 and fed as described for the suture on the left side of FIG. 1. As the view of the vessel is often from the supra-annular or trans-annular space 8 or 10, this method provides the medical professional a better view of the initial insertion of the suture 6 into the vessel wall.
FIG. 3 illustrates a close-up of a mattress stitch of the suture 6. The two ends of the suture 6 feed separately through the same side of the pledget 16. Both ends of the suture 6 then feed into the vessel wall in the trans-annular or infra-annular space 10 or 12. The pledget 16 braces the suture 6 against the vessel wall. Both ends of the suture 6 then feed through the vessel wall and exit the vessel wall in the supra-annular space 8. Both ends of the suture 6 then pass through the sewing ring 14. The ends of the suture 6 are then tied to each other in the knot 18 behind the sewing ring 14, securing the sewing ring 14 to the vessel wall.
During heart valve replacement procedures, the patient is on heart-lung bypass which reduces the patient's oxygen level and creates non-physiologic bloodflow dynamics. The longer a patient is on heart-lung bypass, the greater the risk for complications including permanent health damage. Existing suturing techniques extend the duration of bypass and increase the health risks due to heart-lung bypass. Furthermore, the fixturing force created by suturing varies significantly because the pre-tensioning of the suture just prior to knot tying is difficult to consistently maintain, even for the same medical professional.
There is a need for a fixturing device to minimize the time required to fix a valve prosthesis to a first mass, which can be the surrounding tissue or a second prosthesis. There is also a need for a fixturing device to use a technique familiar to the users of existing devices. Furthermore, there is a need for a device that complements existing suturing devices and methods and reduces fixturing times. Also, there is a need for a fixturing device that does not require visual contact with, or suture access to, the infra-annular space. There also exists a need to provide a fixturing device that can provide a consistent fixturing force. The is also a need for a technique that could reduce the duration of the bypass procedure and minimize the associated health risks.