A catheter device is disclosed for transvascular delivery of a medical device to a cardiac valve region of a patient. The catheter device comprises an elongate sheath (2) with releasable locking members for controllably locking the elongate sheath in a shape at least partly along its length from a relaxed state to a locked state when positioned in relation to a cardiac valve. Furthermore, alignment members (5) are provided to provide for a desired positioning in relation to the cardiac valve. Embolic protection (8) is further provided.