Low profile transcatheter heart valve

An implantable prosthetic valve comprising:

• a radially collapsible and expandable annular frame, the frame having a plurality of angularly spaced commissure attachment posts;
• an annular skirt member positioned inside of and secured to the frame;
• and
• a leaflet structure comprising a plurality of leaflets, the leaflet structure having a scalloped lower edge portion secured to an inner surface of the skirt member, each leaflet having an upper edge, a curved lower edge and two side flaps extending between respective ends of the upper edge and the lower edge, wherein each side flap is secured to an adjacent side flap of another leaflet to form commissures of the leaflet structure, each commissure being attached to one of the commissure attachment posts;
• and
• a reinforcing bar positioned against each side flap for reinforcing the attachments between the commissures and the commissure attachment posts;
• wherein the frame comprises a plurality of axial struts and a plurality of rows of circumferential struts extending between and interconnecting the axial struts;
• wherein the rows of circumferential struts includes at least a first row of circumferential struts adjacent the inflow end of the valve and a second row of circumferential struts adjacent the outflow end of the valve, wherein the struts of the first row are thicker than the struts of the second row.