Transcatheter heart valve delivery system with reduced area moment of inertia

A device for repairing a heart valve of a patient, the device comprising:

• a prosthetic heart valve having a stent frame and a valve structure attached to the stent frame and forming at least two valve leaflets, the prosthetic heart valve being radially self-expandable from a compressed arrangement to a natural arrangement, the stent frame defining an axial length;
• and
• a delivery system comprising:
• an inner shaft assembly including an intermediate portion forming a coupling structure,
• a delivery sheath assembly defining a lumen sized to slidably receive the inner shaft assembly and including:
• a shaft,
• a capsule extending distally from the shaft and having a distal segment defining a first outer diameter and a proximal segment defining a second outer diameter,
• wherein the first outer diameter is greater than the second outer diameter, and an axial length of the distal segment is less than the axial length of the stent;
• wherein the device is configured to provide a loaded state in which the prosthetic heart valve engages the coupling structure and is entirely compressibly retained within the proximal and distal capsule segments, including the proximal and distal segments each contacting and compressibly retaining a corresponding region of the prosthetic heart valve and the first outer diameter is greater than the second outer diameter.