Abstract: An introducer sheath assembly for percutaneously delivering a medical device that maintains hemostasis in a patient. The assembly has a hub, a hub cap and a hemostasis valve. The introducer sheath assembly has a longitudinal axis and a lumen formed therein. The hemostasis valve has a frame portion and a valve portion, the valve portion having a plurality of slits that are offset through the thickness of the valve portion therein and an extension of the frame portion formed from an incompressible material. The extension of the frame portion is received by a valve seat feature in the hub, when the valve is received by the hub. The valve seat feature also receives a seating portion of the hub cap as the hub and hub cap are advanced into engagement, the seating portion of the hub cap advanced into the valve seat feature subjecting the incompressible extension of the frame portion to a compressive force.