Paravalvular leak sealing mechanism

1. A prosthetic heart valve, comprising:

a stent body including a generally tubular annulus section defining a first circumferential row of cells and a second circumferential row of cells distal to the first circumferential row of cells;

one or more prosthetic valve elements mounted to the stent body and operative to allow flow in an antegrade direction but to substantially block flow in a retrograde direction through the annulus section;

a cuff attached to the stent body and positioned on a luminal surface of the stent body;

a plurality of proximal sealing members each attached to the cuff and positioned substantially within a corresponding cell in the first circumferential row of cells, the proximal sealing members having an open side facing in a first axial direction and a closed side facing in a second axial direction opposite the first axial direction so that a flow of blood in the second axial direction will tend to force blood into the proximal sealing members and cause the proximal sealing members to billow outwardly relative to the stent body; and

a plurality of distal sealing members each attached to the cuff and positioned substantially within a corresponding cell in the second circumferential row of cells, the distal sealing members having an open side facing in the first axial direction and a closed side facing in the second axial direction so that the flow of blood in the second axial direction will tend to force blood into the distal sealing members and cause the distal sealing members to billow outwardly relative to the stent body;

wherein the plurality of distal sealing members is circumferentially staggered with respect to the plurality of proximal sealing members such that a center portion of the open side of each distal sealing member aligns generally axially with a point at which the open sides of two adjacent proximal sealing members meet.

2. The prosthetic heart valve of claim 1 , wherein each cell in the first circumferential row of cells includes one of the proximal sealing members positioned substantially therein and each cell in the second circumferential row of cells includes one of the distal sealing members positioned substantially therein.

3. The prosthetic heart valve of claim 1 , further comprising a plurality of commissure attachment features defined by the stent body, wherein each of the distal sealing members is attached to the cuff and positioned substantially within a cell in the second circumferential row of cells directly proximal to a corresponding one of the commissure attachment features.

4. The prosthetic heart valve of claim 3 , further comprising exactly two of the proximal sealing members for each of the distal sealing members, the two proximal sealing members being attached to the cuff at two adjacent cells in the first circumferential row of cells such that a center portion of the open side of each of the distal sealing member aligns generally axially with a point at which the open sides of the two adjacent proximal sealing members meet.

5. A prosthetic heart valve, comprising:

a stent body including a generally tubular annulus section defining a first circumferential row of cells and a second circumferential row of cells distal to the first circumferential row of cells;

one or more prosthetic valve elements mounted to the stent body and operative to allow flow in an antegrade direction but to substantially block flow in a retrograde direction through the annulus section;

a cuff attached to the stent body and positioned on a luminal surface of the stent body;

a plurality of proximal sealing members each attached to the cuff and positioned substantially within a corresponding cell in the first circumferential row of cells, the proximal sealing members having an open side facing in a first axial direction and a closed side facing in a second axial direction opposite the first axial direction so that a flow of blood in the second axial direction will tend to force blood into the proximal sealing members and cause the proximal sealing members to billow outwardly relative to the stent body;

a plurality of distal sealing members each attached to the cuff and positioned substantially within a corresponding cell in the second circumferential row of cells, the distal sealing members having an open side facing in the first axial direction and a closed side facing in the second axial direction so that the flow of blood in the second axial direction will tend to force blood into the distal sealing members and cause the distal sealing members to billow outwardly relative to the stent body; and

a plurality of commissure attachment features defined by the stent body, wherein each of the distal sealing members is attached to the cuff and positioned substantially within a cell in the second circumferential row of cells directly proximal to a corresponding one of the commissure attachment features;

wherein exactly two of the proximal sealing members are included for each of the distal sealing members, the two proximal sealing members being attached to the cuff at two adjacent cells in the first circumferential row of cells such that a center portion of the open side of each of the distal sealing member aligns generally axially with a point at which the open sides of the two adjacent proximal sealing members meet.