Assembly tooling for an autologous tissue heart valve

• US 5,522,885 A
• Filed: 05/05/1994
• Issued: 06/04/1996
• Est. Priority Date: 05/05/1994
• Status: Expired due to Term

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Autogenics Co.
• Inventors: Hudak, Philip J., Suggitt, Robert W., Love, Charles S.
• Primary Examiner(s): Prebilic, Paul B.
• Application Number:
  US08/238,463
• Time in Patent Office: 761 Days
• Field of Search: 623/2, 623/66, 623/901, 137/515.7, 251/365, 29/213.1
• US Class Current: 623/2.11
• CPC Class Codes: A61F 2/2412 with soft flexible valve members, e.g. tissue valves shaped like natural valves check valves with flexible valve members in general F16K15/14
• CPC Class Codes: A61F 2/2415 Manufacturing methods
• CPC Class Codes: Y10S 623/901 Method of manufacturing prosthetic device
• CPC Class Codes: Y10S 623/91 Heart
• CPC Class Codes: Y10T 137/7857 Valve seat clamped between coupling elements

Abstract

An assembly tool for a bioprosthetic heart valve is disclosed. The tool assembles a valve having an inner and a spreadable outer stent, and includes a spreading ring with an elevated lip to hold the spread outer stent, an expander having fingers which contact the outer stent base to spread it apart, and a plunger to spread the fingers of the outer stent. An assembly mandrel having indexing rails allows the insertion of the inner stent into the spread outer stent while maintaining the correct rotational positioning of both stents. A shedding cap protects the tissue wrapped on the inner stent from abrasion during insertion.

Claims

1. An assembly tool for assembling a bioprosthetic heart valve having an inner stent with an annular base and a plurality of posts extending from the base along an axis of the valve, said inner stent covered with tissue, and an outer stent having an annular base and a plurality of posts extending from the base along an axis of the valve, said outer stent mating with and clamping said tissue to said inner stent, said assembly tool (i) expanding the base of said outer stent to a spread position so that the forces applied to said base uniformly distribute the stress on said base during the spreading operation and optimally apply the spreading forces to substantially the midpoint between adjacent posts, (ii) maintaining proper alignment of the outer stent with respect to said tool during the spreading procedure, (iii) precisely rotationally and axially aligning said inner stent and said outer stent during the mating of the outer stent to the inner stent, and (iv) protecting the tissue covering said inner stent during the assembly procedure, said assembly tool comprising:

an expander having three flexible fingers for engaging the inside of the base of the outer stent and applying an initial outward radial force to said base when said fingers are actuated to expand the outer stent from an unspread to a spread position,

a spreading ring for maintaining the base in said spread position, said base having a plurality of lobed surfaces having an arcuate circumferential profile substantially corresponding in radius to the radius of the outer stent base in its unspread position so as to uniformly distribute the stress on said base during the spreading operation;

a plunger insertable into said expander, said plunger having a distal and a proximal end and distal, center, and proximal cylindrical members, said center member engaging the inner surfaces of each of said fingers and radially outwardly forcing said fingers when said plunger is inserted into said expander, said distal cylindrical member radially aligning said center cylindrical member with respect to said fingers of said expander when said plunger is inserted into said expander;

a protective cap engageable with said proximal surface of said plunger, said cap including three alignment slots engageable with the fingers of said expander, said cap further including an upper flange having three cutouts capable of registering with said posts of said outer stent spaced at equal intervals along said flange, said cutouts and said alignment slots cooperating to prevent rotational movement of said outer stent with respect to said fingers of said expander when said cutouts are registered with said outer stent and said alignment slots are engaged with said fingers;

an assembly mandrel for inserting said inner stent through said spreading ring into said outer stent when said outer stent is held on said spreading ring in a spread position, said assembly mandrel including a plurality of indexing rails engageable with said spreading ring, said indexing rails fixing the angular relationship of said spreading ring and said assembly mandrel when said mandrel is used to insert said inner stent into said outer stent; and

a shedding cap placed over the tissue wrapped on said inner stent when said inner stent is placed on said assembly mandrel, said shedding cap protecting said tissue from abrasion during the insertion of said inner into said outer stent.

2. An assembly tool for assembling a bioprosthetic heart valve having an inner stent with an annular base and a plurality of posts extending from the base along an axis of the valve, said inner stent covered with tissue, and an outer stent having an annular base and a plurality of posts extending from the base along an axis of the valve, said outer stent mating with and clamping said tissue to said inner stent, said assembly tool comprising:

a spreading assembly engaging the base of said outer stent and forcing said outer stent into a spread position;

a mandrel for mating the inner stent to the outer stent when said outer stent is in a spread configuration; and

indexing rails mounted to said mandrel, said indexing apparatus ensuring proper radial and axial alignment of said inner stent with said outer stent.

3. An assembly tool for assembling a bioprosthetic heart valve having an inner stent with an annular base and a plurality of posts extending from the base along an axis of the valve, said inner stent covered with tissue, and an outer stent having an annular base and a plurality of posts extending from the base along an axis of the valve, said outer stent mating with and clamping said tissue to said inner stent, said assembly tool expanding the base of said outer stent to a spread position so that the forces applied to said base uniformly distribute the stress on said base during the spreading operation, said assembly tool comprising:

an expander having three flexible fingers for engaging the inside of the base of the outer stent and applying an initial outward radial force to said base when said fingers are actuated to expand the outer stent from an unspread to a spread position;

a spreading ring for maintaining the base in said spread position;

a plunger insertable into said expander, said plunger engaging the inner surface of each of said fingers and radially outwardly forcing said fingers when said plunger is inserted into said expander; and

an assembly mandrel for inserting said inner stent through said spreading ring into said outer stent when said outer stent is held on said spreading ring in a spread position, said assembly mandrel including a plurality of indexing rails engageable with said spreading ring, said indexing rails fixing the angular relationship of said spreading ring and said assembly mandrel when said mandrel is used to insert said inner stent into said outer stent.

4. The assembly tool of claim 3, further comprising a protective cap placed over said plunger and having a base and top portion, said base portion having a plurality of slots cut therein, said slots receiving the fingers of said expander, said top portion having a plurality of recesses, said recesses receiving the posts of said outer stent, said slots and recesses preventing rotation of said stent with respect to the fingers of said expander when said protective cap is placed over said plunger.

5. The assembly tool of claim 3, wherein said bottom portion of said mandrel further comprises a plurality of indexing rails, said indexing rails registering with the slots in said spreading ring to ensure that said posts of said inner and said outer stents are correctly aligned.

6. The assembly tool of claim 3, wherein said elevated lip further comprises a plurality of lobes, each of said lobes having a radius of curvature substantially equal to the inner radius of said outer stent, said lobes providing a surface for uniform contact between said elevated lip and the inner surfaces of said base of said outer stent.

7. The assembly tool of claim 3, wherein said shedding cap has a plurality of arms, each of said arms contacting one of the posts of said inner stent, said arms thereby protecting the tissue mounted on said inner stent from abrasion.

8. The tool of claim 3, further comprising a shedding cap placed over said tissue to protect said tissue from abrasion during the mating of said inner stent into said outer stent.

9. The assembly tool of claim 3, further comprising a spring disposed on said annular expander for urging the elevated lip of said spreading ring into contact with the annular base of said outer stent when said outer stent is in a spread position.

10. An assembly tool for assembling a bioprosthetic heart valve having an inner stent with an annular base and a plurality of posts extending from the base along an axis of the valve, said inner stent covered with tissue, and an outer stent having an annular base and a plurality of posts extending from the base along an axis of the valve, the base of said outer stent expandable from a rest position to a spread position, said outer stent mating with and clamping said tissue to said inner stent, said assembly tool comprising:

an annular spreading ring having inner and outer surfaces, a plurality of slots cut in said inner surface in an axial direction, and an elevated lip, said elevated lip including lobed surfaces configured to engage the annular base of said outer stent when said base is in a spread position;

an annular expander having inner and outer surfaces and a top surface with three fingers connected thereto, said outer surface capable of insertion into said spreading ring, each of said fingers registering with one of said slots cut in said inner surface of said spreading ring and each of said fingers engaging the annular base of said outer stent, said fingers movable from a rest position to a spread position, said fingers moving the base of said outer stent to a spread position when said fingers are moved to a spread position;

a plunger having cylindrical outer surfaces, said plunger engageable with said inner surface of said expander, said plunger outer surfaces forcing said fingers of said annular expander to said spread position when said plunger is inserted into said expander;

a mandrel having a base and a top portion, said top portion configured to secure said inner stent in place when said inner stent is placed over said top portion, said top portion engageable with said inner surface of said spreading ring to insert said inner stent into said outer stent when said outer stent is in a spread position; and

a shedding cap covering said tissue on said inner stent and shielding said tissue mounted to the inner stent from abrasion when said inner stent is placed inside said outer stent.

11. A tool for assembling a bioprosthetic heart valve having an inner stent with an annular base and a plurality of posts extending from the base along an axis of the valve, said inner stent covered with tissue, and an outer stent having an annular base and a plurality of posts extending from the base along an axis of the valve, the base of said outer stent expandable from a rest position to a spread position, said outer stent mating with and clamping said tissue to said inner stent, said tool comprising:

an annular spreading ring having inner and outer surfaces, a plurality of slots cut in said inner surface in an axial direction, and an elevated lip having a plurality of lobes, each of said lobes having a radius of curvature substantially equal to the inner radius of said outer stent, said lobes providing a surface for uniform contact between said elevated lip and the inner surfaces of said base of said outer stent when said base is in a spread position;

an annular expander having inner and outer surfaces and a top surface with a plurality of fingers connected thereto, said outer surface capable of insertion into said spreading ring, each of said fingers registering with one of said slots cut in said inner surface of said spreading ring and each of said fingers engaging the annular base of said outer stent, said fingers movable from a rest position to a spread position, said fingers moving the base of said outer stent to a spread position when said fingers are moved to a spread position;

a plunger having cylindrical outer surfaces, said plunger engageable with said inner surface of said expander, said plunger outer surfaces forcing said fingers of said annular expander to said spread position when said plunger is inserted into said expander;

a mandrel having a base and a top portion, said top portion configured to secure said inner stent in place when said inner stent is placed over said top portion, said top portion engageable with said inner surface of said spreading ring to insert said inner stent into said outer stent when said outer stent is in a spread position, and said bottom portion having a plurality of indexing tangs, said indexing tangs registering with the slots in said spreading ring to ensure that said posts of said inner and said outer stents are correctly aligned; and

a shedding cap covering said tissue on said inner stent and shielding said tissue mounted to the inner stent from abrasion when said inner stent is placed inside said outer stent.