A connection system for connecting a hemostasis valve to a splittable sheath is disclosed. The connection system includes an adapter fitting having a shaft defining a lumen. The shaft has a proximal end and a distal end. On an external surface of the proximal end of the shaft, threading is provided for engagement with the hemostasis valve. A cannula portion defines the distal end of the shaft for interfacing with a splittable sheath. A wedge is disposed on an external surface of the cannula portion for interfacing with a weakened portion of the splittable sheath. A sliding connector is disposed about the shaft for engagement with the splittable sheath. Upon a first level of engagement between the sliding connector and the splittable sheath, a fluid-tight seal is created. Upon a second level of engagement between the sliding connector and the splittable sheath, the wedge initiates separation of the splittable sheath.