Collapsible leaflets for prosthetic heart valves

A prosthetic heart valve, comprising:

• an expandable stent having an inflow end, an outflow end, an annulus section adjacent the inflow end, and a plurality of cells connected to one another in a plurality of annular rows around the stent;
• a cuff attached to the annulus section of the stent;
• and
• a plurality of leaflets disposed within an interior region of the stent and attached to at least one of the cuff or the stent, the leaflets together having a coapted position occluding the interior region of the stent and an open position in which the interior region is not occluded, each of the leaflets including a primary leaflet material, and each of the leaflets having a thickness that varies from a belly edge of the leaflet to a free edge of the leaflet;
• wherein each of the leaflets has an outer surface and a plurality of regions adjacent to one another in lateral directions parallel to the outer surface, a first one of the regions adjacent the belly edge having a first constant thickness and a second one of the regions adjacent the free edge having a second constant thickness less than the first constant thickness;
• wherein the first one of the regions is formed from first and second layers of the primary leaflet material, the first layer is stacked atop the second layer so that the first and second layers together have the first constant thickness, and the second one of the regions is formed from the second layer that has the second constant thickness.

A prosthetic heart valve, comprising:

• an expandable stent having an inflow end, an outflow end, an annulus section adjacent the inflow end, and a plurality of cells connected to one another in a plurality of annular rows around the stent;
• a cuff attached to the annulus section of the stent;
• and
• a plurality of leaflets disposed within an interior region of the stent and attached to at least one of the cuff or the stent, the leaflets together having a coapted position occluding the interior region of the stent and an open position in which the interior region is not occluded, each of the leaflets including a primary leaflet material, and each of the leaflets having a thickness that varies from a belly edge of the leaflet to a free edge of the leaflet;
• wherein each of the leaflets has an outer surface and a plurality of regions adjacent to one another in lateral directions parallel to the outer surface, a first one of the regions adjacent the belly edge having a first constant thickness and a second one of the regions adjacent the free edge having a second constant thickness less than the first constant thickness;
• wherein the first one of the regions is formed from a first layer of the primary leaflet material that has the first constant thickness, and the second one of the regions is formed from a second layer of the primary leaflet material that has the second constant thickness, and the first and second layers are disposed adjacent to one another in the lateral directions.