Disclosed is a medical device for shaping a vessel accommodated therein in a predetermined form, wherein said vessel includes a vein and an artery which are connected at a artifactual vascular junction thereof. The device includes an external vascular support (100) having at least one vascular support wall for accommodating an exterior vessel wall of a vessel therein when implanted. The support includes an arterial portion (1304) for apposition with said artery when accommodated therein, and/or a venous portion (1302) for apposition with said vein when accommodated therein. The venous portion (1302) and/or said arterial portion (1304) are shaped at a junction thereof to provide a vessel rounding to at least a portion of said vessel junction when in apposition with the latter upon implantation of said device for said vessel shaping. Corresponding methods are also disclosed. Thus dysfunction or failure of a vessel of the artifactual vascular junction may be reduced, minimized, or eliminated.
