A
catheter system (1, 1 ') for interventional procedures within a patient's heart, vasculature and / or an
implant (42) secured at a patient's heart or vasculature (50, 51, 52) is described, comprising a bendable and / or steerable extension arm (12) and a guide sheath (10) having a distal section, which allows for precise and effective localization of perivalvular leaks and deployment of
occlusion members. The extension arm is fixed at a distal end of the distal section of the guide sheath, or is configured to move along the guide sheath such that the extension arm protrudes from the distal end of the distal section in an operative position, where the extension arm has a lumen through which the guidewire (17) can be manipulated and which defines a longitudinal axis (15), where the
catheter system further comprises at least one alignment member (20, 120, 220, 320, 420, 520), where the alignment member (20, 120, 220, 320, 420, 520) is configured to align the guidewire (17) to the extension arm (20, 120, 220, 320, 420, 520). And an alignment member having a collapsed state and configured to be deployed to a deployed state in which the alignment member is attached to the guide sheath at a predetermined position within the distal section but proximally from a distal end thereof, or the alignment member is configured to advance along the guide sheath to a predetermined position within the distal section, wherein the alignment component comprises a plurality of struts (21, 28) distributed over a circumference, and wherein each strut of the plurality of struts extends at least in sections into a radial direction and / or is inclined with respect to the longitudinal axis in the deployed state, thereby creating a radially outwardly directed force and supporting the alignment component on the heart, vasculature and / or
implant of the patient. Furthermore, a method for closing at least one
perivalvular leak (53) is interpreted.