An arrangement includes a first sleeve； a fixing device for fixing to vascular wall tissue； and a second sleeve. The fixing device includes a tubular element for accommodation within a passage surrounded by vascular wall tissue and is provided with fingers arranged distributed in the peripheral direction of the tubular element. The fingers have a first position in which they project radially outwards from the tubular element. The fingers are bent aside reversibly, against a resilient force, from the first position into a second position in which the projection of the fingers on a radial transverse surface of the tubular element is located essentially on and/or within the periphery of the tubular element. The fingers are fixed in the second position by the first sleeve in which the tubular element and fingers, which are in the second position, are accommodated to form a composite assembly.
