A system and process for placing a percutaneous valve device in a body lumen at the location of implantation is provided, which enhances the accuracy of the placement. Anchors and placement wires are used to fix the implantation target and guide the device to the implantation site. The system and method are applicable to preassembled percutaneous valve devices as well as a modular prosthetic valve device. The modular valve device comprises two or more device modules and is designed to be delivered unassembled and then assembled in the body lumen at or near the site where implantation occurs. The device modules may be assembled before or after the implantation target is fixed with the anchor, and then placed using the placement system in a manner similar to how a preassembled percutaneous valve device may be placed in accordance with the invention.