| abstract |
A system and method for assembling a prosthetic heart valve, including a procedure for tightly wrapping fabric around a heart valve support stent. The support stent typically includes alternating cusps and commissures that create a highly contoured undulating outflow edge. The system includes a mandrel for retaining tension without manual assistance in a tubular length of fabric wrapped over the support stent. The mandrel may include an inner clamping mechanism for holding the first end of the fabric tube, a pedestal tube on which the support stent rests and through which the fabric tube passes, and an outer clamping mechanism for holding the free end of the fabric tube. The inner and outer clamping mechanisms include discrete clamps spaced apart 120° from each other that pull the fabric only in the cusps of the support stent. The inner clamping mechanism, outer clamping mechanism, and pedestal are relatively axially movable. Once the fabric is retained over the support stent, the mandrel may be placed in a chuck of a sewing machine system for automatically forming the seam. A small shuttle with bobbin thread reciprocates within a channel inside of the support stent and cooperates with the sewing machine needle to form a lock-stitch in the fabric tube. The mechanization of the fabric covering procedure greatly enhances manufacturing throughput and reduces ergonomic strain on workers. |