Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
  • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
  • A61F2/02—Prostheses implantable into the body
  • A61F2/24—Heart valves ; Vascular valves, e.g. venous valves; Heart implants, e.g. passive devices for improving the function of the native valve or the heart muscle; Transmyocardial revascularisation [TMR] devices; Valves implantable in the body
  • A61F2/2442—Annuloplasty rings or inserts for correcting the valve shape; Implants for improving the function of a native heart valve
  • A61F2/2445—Annuloplasty rings in direct contact with the valve annulus
  • A61F2/2448—D-shaped rings
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
  • A61F2250/00—Special features of prostheses classified in groups A61F2/00 - A61F2/26 or A61F2/82 or A61F9/00 or A61F11/00 or subgroups thereof
  • A61F2250/0014—Special features of prostheses classified in groups A61F2/00 - A61F2/26 or A61F2/82 or A61F9/00 or A61F11/00 or subgroups thereof having different values of a given property or geometrical feature, e.g. mechanical property or material property, at different locations within the same prosthesis
  • A61F2250/0018—Special features of prostheses classified in groups A61F2/00 - A61F2/26 or A61F2/82 or A61F9/00 or A61F11/00 or subgroups thereof having different values of a given property or geometrical feature, e.g. mechanical property or material property, at different locations within the same prosthesis differing in elasticity, stiffness or compressibility

Definitions

• the present invention relates generally to medical devices, specifically to an annuloplasty ring and related procedure for surgically reconstructing the mitral valve annulus of a patient's heart. More specifically, this invention relates to a mitral valve repair device and corresponding technique that conforms to an abnormal annulus in the pathology encountered with functional mitral regurgitation having a posterior aspect depressed below the anterior aspect.
• the left atrium receives oxygenated blood from the lungs through the pulmonary vein.
• the mitral valve separates the left atrium from the left ventricle.
• oxygenated blood passes through the mitral valve into the left ventricle.
• the aortic valve leading into the ascending aorta closes, allowing the left ventricle to fill with blood.
• a similar flow of venous blood occurs from the right atrium through the pulmonary valve to the right ventricle. Once the ventricles are full, they contract during the systolic phase and pump blood out of the heart.
• the mitral valve closes and the aortic valve opens, thus preventing blood from regurgitating into the left atrium and forcing blood into the aorta, and from there throughout the body. Because of the high pressures associated with the left ventricle during systole, proper functioning of the mitral valve to prevent blood from flowing back through the system is extremely important.
• the various anatomical components of the left ventricle LV and mitral valve MV are depicted in Fig. 1 as seen in vertical cross-section along an anterior-posterior plane.
• the mitral annulus MA comprises a fibrous ring encircling the orifice between the left atrium LA and the left ventricle LV.
• the average human mitral annular cross-sectional area is 5-1 1 cm 2 .
• the anterior aspect of the mitral annulus MA forms a part of the "cardiac skeleton" and includes left and right fibrous trigones, LT and RT.
• Fig. 3 illustrates the mitral valve from the left atrium as exposed during surgery.
• the mitral valve is a bicuspid valve having a posterior leaflet PL that cooperates with an anterior leaflet AL.
• chordae tendineae CT extend between and link the papillary muscles Pi and P 2 and free edges of the anterior and posterior leaflets AL and PL.
• the chordae tendineae are string-like in appearance and are sometimes referred to as "heart strings.”
• chordae tendoneae CT extend between each of the papillary muscles Pi and P 2 and both leaflets.
• dilation of the left ventricle LV generally increases the distance between the papillary muscles Pi and P 2 and the mitral annulus MA. This in turn increases the tension in the chordae tendonae CT.
• the droop or depression of the posterior aspect of the annulus below the datum plane 20 by the distance h in combination with the increased tension in the chordae reduces the ability of the leaflets to come together during systole.
• Annuloplasty rings have been developed in various shapes and configurations over the years to correct mitral regurgitation and other conditions which reduce the functioning of the valve.
• Carpentier, et al. in U.S. Patent No. 4,055,861 disclosed two semi-rigid supports for heart valves, one of which being closed (or D-shaped) and the other being open (or C- shaped). In the closed configuration, the ring is generally symmetric about an anterior-posterior plane, and has a convex posterior side and a generally straight anterior side.
• 5,104,407, 5,201 ,880, and 5,607,471 all disclose closed annuloplasty rings that are bowed slightly upward on their anterior side. Because the anterior aspect of the mitral annulus MA is fibrous and thus relatively inflexible (at least in comparison to the posterior aspect), the upward curve in the anterior side of each ring conforms that ring more closely to the anatomical contour of the mitral annulus, and thus reduces undue deformation of the annulus.
• 5,258,021 and 6,231,602 disclose sinusoidal or so-called "scalloped" annuloplasty rings that follow the up-and-down shape of the three cusp aortic annulus. Such rings would not be suitable for correcting a mitral valve deficiency.
• the present invention provides an annuloplasty ring for implantation in a mitral valve annulus that has a pathologic condition such that the posterior aspect thereof droops downward abnormally.
• the annuloplasty ring includes a rounded ring body having an anterior section and a posterior section.
• the ring body is oriented about a central flow axis that defines an upward direction and a downward direction, the downward direction corresponding to the direction of blood flow through the mitral valve annulus.
• the posterior section the ring body bows downward out of a plane perpendicular to the central flow axis.
• the ring body may bow downward between about 2- 15 mm from one end thereof to a lowest point, and desirably bows downward between about 4-8 mm from one end thereof to a lowest point.
• the bow in the ring body may or may not be centered in the posterior section.
• the ring body is made of a malleable material such that the bow in the ring body may be manually reshaped.
• the ring body is made of a semi-rigid material that will retain its posterior bow in opposition to the stresses that will be imparted by muscles of the heart throughout each beating cycle.
• the ring body may be substantially planar except in the posterior section, or an anterior section of the ring body may bow upward from one end thereof to a lowest point.
• the ring body In plan view, as seen along the flow axis, the ring body preferably defines an oval shape with a major axis perpendicular to a minor axis, the minor axis bisecting both the anterior and posterior sections. Further, the bow in the posterior section may begin at symmetric locations across the minor axis that are spaced from the major axis around the ring body by an angle ⁇ of between about 0-45°, more preferably about 30°.
• the ring body may further include two upward bows on either side of the downward bow on the posterior section, and wherein downward bow may be between about 2-15 mm.
• the ring body comprises a plurality of ring elements concentrically disposed. A polymer strip in between each ring element may be provided.
• the ring elements comprise bands that have a substantially larger height in the flow axis dimension than in the dimension perpendicular to the flow axis. Further, the ring elements may have varying heights so that the ring body is more flexible in the posterior section than around the remainder of the ring body.
• Another aspect of the present invention is a method of repairing a mitral heart valve annulus that has a posterior aspect that is depressed downward along the blood flow axis relative to an anterior aspect.
• the method includes implanting an annuloplasty ring having an anterior section sized to fit the anterior aspect of the annulus and a posterior section sized to the posterior aspect, wherein the ring posterior section bows downward parallel to the central axis relative to the anterior section.
• the annuloplasty ring may be malleable and the surgeon adjusts the bow in the posterior section manually.
• Fig. 1 is a cross-section of a healthy left ventricle through the mitral valve between the anterior and posterior leaflets
• Fig. 2 is a cross-section of a dilated left ventricle through the mitral valve between the anterior and posterior leaflets
• Fig. 3 is an atrial view of the mitral valve of Fig. 2 exposed during a surgical procedure;
• Fig. 4 is a plan view of annuloplasty ring of the present invention implanted so as to restore competency to the mitral valve;
• Fig. 5 is a perspective view of an annuloplasty ring of the present invention over an abnormal mitral valve as viewed from the posterior side;
• Fig. 6 is a perspective view of the annuloplasty ring of Fig. 5 over the abnormal mitral valve as seen from the side;
• Figs. 7A-7C are plan, front, and side views of an exemplary annuloplasty ring of the present invention having a posterior bow;
• Figs. 8A-8C are plan, front, and side views of an alternative annuloplasty ring of the present invention having a posterior bow between two raised portions;
• Fig. 10 is a top plan view of an inner ring body of an annuloplasty ring of the present invention showing details of a composite band construction.
• FIG. 4 An exemplary annuloplasty ring 30 of the present invention is shown in Fig. 4 implanted around a mitral annulus MA. As described above, the mitral annulus has an anterior leaflet AL and a posterior leaflet PL. When the ring 30 is implanted, the leaflets are brought closer together and supported so that they meet at a coaptation surface 32. The ring 30 thus corrects the problem of functional mitral regurgitation.
• the ring 30 has an oval or somewhat D-shaped configuration with a relatively straight anterior section 34 opposite a curved posterior section 36.
• a pair of trigone or commissure markers 38a, 38b generally delimit the anterior side 34, while a pair of opposed side sections 40a, 40b extend between each of these markers and the posterior section 36.
• a plurality of knotted suture loops 42 are typically used to secure the ring 30 to the mitral annulus MA, although other fasteners such as staples, fibrin glue, or the like may be used.
• the posterior aspect of the mitral annulus is depressed relative to the anterior aspect, as is illustrated in Fig. 2.
• the posterior aspect will be depressed into the page relative to the anterior aspect.
• the annuloplasty ring 30 of the present invention has a shaped posterior section 36 that generally follows the modified shape of the mitral annulus MA. In other words, the posterior section 36 is bowed into the page relative to the anterior section 34.
• the ring 30 supports the mitral annulus MA in its modified shape, rather than trying to revert the annulus back to the original substantially planar configuration.
• the ring 30 desirably constricts the orifice circumference defined by the annulus so as to bring the anterior leaflet AL and posterior leaflet PL closer together. Because the ring 30 does not pull the posterior aspect of the mitral annulus MA upward from its modified position, high stresses are not set up in the attachment sutures 42 and thus there is less potential for the dehiscence.
• FIG. 7A illustrates orthogonal axes wherein the X- and Y-axes generally define the datum plane 20 as mentioned above with respect to Figs. 1 and 2.
• the X-axis extends across the ring 30 from one side 40a to the opposite side 40b at the point of maximum dimension.
• the X-axis thus defines a major axis of the ring 30.
• the Y-axis defines a plane of symmetry for the ring 30 extending between a midpoint of the anterior side 34 to a midpoint of the posterior section 36.
• the Y-axis also defines a minor axis for the ring 30.
• Several points are noted around the ring 30 to help describe the posterior bow. These points, and the ones shown in Figs. 8A-8B, are imaginary center points through the cross-section of the ring 30. Two points A are symmetrically located on either side of the Y-axis at an angular distance ⁇ from the X-axis. The midpoint of the posterior section 36 is denoted B. The ring 30 has a posterior bow such that the point B is at the lowest elevation along the Z-axis. The magnitude of this posterior bow is indicated by the dimension Z
• the downward bow or posterior bow preferably extends along a majority of the posterior section 36 between the points A, which points are between 0 and 45° from the X-axis ( ⁇ ). More preferably, the points A are between 20-40°, and more particularly about 30° from the X-axis.
• the magnitude of bow Zj may be between about 2-15 mm (0.08-0.59 inches), and more typically is between about 4-8 mm (0.16-0.31 inches), depending on the size of the ring.
• the ring 30 is shown in Figs. 7A-7C as symmetric about the Y- axis, it does not necessarily have to be so.
• the point B may be displaced from the Y-axis such that the downward bow is not centered in the posterior section 36.
• An asymmetric ring is shown and described below with reference to Figs. 9A and 9B.
• Figs. 8A-8C illustrate an alternative annuloplasty ring 50 of the present invention that has both upward and downward bows. Again, the ring 50 is shown complete with a fabric covering.
• the ring 50 includes an anterior section 52, a posterior section 54, and a pair of side sections (not numbered) therebetween.
• the ring 50 is generally planar on the anterior section 52 and shaped on the posterior section 54.
• the points A symmetrically disposed across the Y-axis again denote the locations on each side where the ring 50 begins to curve out of a plane.
• the ring curves upward in the Z- direction from the points A, as best seen in Fig. 8B, to high points C, and then dips downward to the midpoint B of the posterior section 54.
• the downward bow of the ring between points A and B is shown in Fig. 8C as the dimension Z 2 , which has a magnitude similar to that given for Zi in Fig. 7C.
• the upward curve may be selected so as to better match the patient's annulus shape.
• the anterior section 52 may be upwardly bowed by a distance of between about 2-4 mm (0.08-0.16 inches).
• the points A are desirably disposed an angular distance ⁇ from the X-axis of between about 0-15°, and more desirably between about 5-10°.
• the points C of maximum height of the ring 50 are preferably spaced an angular distance ⁇ from the X-axis of between about 15-45°, and more preferably between about 25-35°.
• the lowest point B of the ring 50 may be bowed along the Z-axis as in the embodiment of Figs. 7A-7C, so that, as indicated Fig.
• Z2 is desirably between about 2-15 mm (0.08-0.59 inches), and more typically is between about 4-8 mm (0.16-0.31 inches), depending on the size of the ring. Therefore, the total height of the ring 50 is at least 2 mm, and may be greater than 15 mm.
• Figs. 9A and 9B show an inner ring body 60 for use in an annuloplasty ring of the present invention.
• the ring body 60 has a posterior bow 62 that is offset from the center of a posterior section 64.
• the bow 62 is offset toward the posterio-medial side (to the right) by about 20% of the entire major axis width of the ring body 60.
• Another way to state the offset is that, in plan view, the bow 62 is centered at a clock position, with 12:00 being centered in the anterior side. In that sense, the bow 62 is centered between 3:00 and 6:00, and more preferably is centered at about 5:00.
• the axial bow Z 3 is shown and may vary from about 2.0 mm (0.08 inches) to about 4.0 mm (0.16 inches), and more preferably from about 3.0 mm (0.12 inches) to about 3.8 mm (0.15 inches), depending on ring size.
• the ring body 60 has an anterior section 66 that is upwardly bowed by a distance of between about 2-4 mm (0.08-0.16 inches).
• the inner ring body 60 demonstrates an asymmetric ring that conforms to patients that have a posterior annular bow that is displaced from the midline. It is believed that most patients have such a malformed anatomy resulting from the pathologic conditions described herein. However, posterior bows that are centered or even offset to the left have been observed. Therefore, one configuration of ring that is embodied in the present invention is one that is pre- shaped with a posterior bow in the middle or to the right, and that is malleable so that the bow can be exaggerated or diminished by the surgeon after examination of the precise shape of the patient's annulus. Further, in such a convertible ring the bow can even be displaced, from the right to the left, for example. Although the material of the ring permits manual deformation, it would be stiff enough to withstand further deformation once implanted and subjected to normal physiologic stresses.
• the ring preferably includes an inner ring body and an outer sewing sheath that pemiits the ring body to be sutured into the mitral annulus.
• the sewing sheath should be sufficiently porous and/or flexible to permit sutures to be passed therethrough.
• One exemplary construction is to enclose the inner ring body in a tubular sheath of suture-permeable material, such as silicone, which is then covered with a fabric ntbe, such as polyethyl terapthalate.
• the annuloplasty ring of the present invention must be semi-rigid. It must retain its posterior bow in opposition to the stresses that will be imparted by muscles of the heart throughout each beating cycle.
• the ring body may be made from materials such as Elgiloy (a cobalt-nickel alloy), titanium, or Nitinol (a nickel- titanium alloy).
• Fig. 10 illustrates one exemplary construction of the inner body of the annuloplasty rings of the present invention that utilizes multiple flat bands of Elgiloy in a composite structure.
• the four bands are concentrically disposed in the shape of the ring.
• Each band is a flat strip of material having a width of between about 1.4-2.0 mm (0.056-0.078 inches).
• the bands 70 overlap in the anterior section 72 of the ring body and are fastened together by, for example, spot welding at multiple points.
• the width of each strip may also be greater in the anterior section 72 than in a posterior section 74, which means that the ring body is more flexible in the posterior section than in any other section.
• a plurality of strips of protective film is used in between each band 70, and on the outer face of the outer band 70a.
• the strips may be a polymer such as Mylar. The strips help reduce rubbing between the bands 70 and also deflect suture needles from the outer band 70a and thus prevent scratching thereto.

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• Health & Medical Sciences (AREA)
• Cardiology (AREA)
• Oral & Maxillofacial Surgery (AREA)
• Transplantation (AREA)
• Engineering & Computer Science (AREA)
• Biomedical Technology (AREA)
• Heart & Thoracic Surgery (AREA)
• Vascular Medicine (AREA)
• Life Sciences & Earth Sciences (AREA)
• Animal Behavior & Ethology (AREA)
• General Health & Medical Sciences (AREA)
• Public Health (AREA)
• Veterinary Medicine (AREA)
• Prostheses (AREA)
• Surgical Instruments (AREA)

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Cited By (55)

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• 2002
  • 2002-07-08 US US10/192,516 patent/US6858039B2/en not_active Expired - Lifetime
• 2003
  • 2003-07-03 DE DE60308523T patent/DE60308523T2/de not_active Expired - Lifetime
  • 2003-07-03 AU AU2003248833A patent/AU2003248833B2/en not_active Expired
  • 2003-07-03 AT AT03763288T patent/ATE339934T1/de not_active IP Right Cessation
  • 2003-07-03 JP JP2004519963A patent/JP4384978B2/ja not_active Expired - Lifetime
  • 2003-07-03 WO PCT/US2003/021208 patent/WO2004004607A1/en not_active Ceased
  • 2003-07-03 BR BRPI0312502-5A patent/BR0312502B1/pt active IP Right Grant
  • 2003-07-03 EP EP03763288A patent/EP1519695B1/en not_active Expired - Lifetime
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