The prosthesis (1) has sealed mechanical connecting units (4) for connecting individual tubular elements (2) to each other. The connecting units include crowns, where each crown is fixed to a free end of each tubular element. A seal is carried by one of the crowns and interposed between the crowns around an opening (3). Clamping rings (9A, 9B) are traversed by the tubular element, and cooperate with each other for maintaining the crowns. The rings hold the crowns against one another and ensure compression of the seal between the crowns.
