Implantable valve prosthesis

An implantable valve prosthesis (1) adapted for preventing blood reflux from a cardiac atrium into a vein opening into the atrium, comprising

• a generally tubular stent (2) which may be branched or unbranched and which comprises at least a first end section (4) with a first end opening (6) and a second end section (5) with a second end opening (7), and
• a flexible elastic tube (3) which may be branched or unbranched and which has at least a first end section (8) with a first end opening (10) and a second end section (9) with a second end opening (11) and which is disposed at least in a sub-region of the second end section (9) of the stent (2) on the outer peripheral surface thereof in a manner such that the second end section (9) of the flexible elastic tube (3) with its second end opening (11) protrudes beyond the second end opening (7) of the stent (2),
• wherein the flexible elastic tube (3) widens in cross-section towards its second end opening (11) such that the second end opening (11) is wider than the first end opening (10),
• wherein the second end opening (11) of the flexible elastic tube (3) is open in the unpressurized state with no pressure difference between the interior of the tube and the exterior of the tube, and
• wherein the second end opening (11) of the flexible elastic tube (3) is adapted to collapse under pressurized conditions which arise under physiological conditions in a cardiac atrium during systole so that the tube wall of the flexible elastic tube (3) is drawn or pressed towards the interior of the flexible elastic tube (3) and regions of the inner wall of the flexible elastic tube (3) lie on one another and reversibly close the flexible elastic tube (3).