A hemostasis mechanism includes a housing, and a pressure responsive seal positioned within the housing and having an outer seal surface exposed to a fluid pressure of a port formed in the housing. A pressurization device is in fluid communication with the port, and includes a detent having a release state, and an engaged state holding a plunger of the pressurization device at an advanced position to maintain an increased fluid pressure supplied to the pressure responsive seal to maintain sealing engagement about a transluminal device. Related methodology is also disclosed.