A medical implant for providing external support to an arteriovenous fistula, the medical implant comprising: a mesh-like main tubular body configured to transition between an opened configuration and a closed configuration, in which the main tubular body defines a longitudinally-extending main passageway therethrough configured to receive a first blood vessel, the main tubular body being resiliently biased toward the closed configuration, the main tubular body including: a proximal end portion defining an opening in communication with the main passageway; a distal end portion defining an opening in communication with the main passageway; and an intermediate portion disposed between the proximal end portion and the distal end portion, wherein the intermediate portion defines a side opening in communication with the main passageway and configured to receive and support a second blood vessel therein, wherein the main tubular body has a pair of longitudinal edges configured to be disposed adjacent one another when the main tubular body is in the closed configuration, the pair of longitudinal edges together defining a seam that extends along a length of the main tubular body, the seam and the side opening being disposed in opposing relation to one another; and the opening of the intermediate portion being formed by a looped filament positioned in substantially opposing or diametrically opposing relation with the longitudinal seam of the main tubular body. a mesh-like main tubular body configured to transition between an opened configuration and a closed configuration, in which the main tubular body defines a longitudinally-extending main passageway therethrough configured to receive a first blood vessel, the main tubular body being resiliently biased toward the closed configuration, the main tubular body including: a proximal end portion defining an opening in communication with the main passageway; a distal end portion defining an opening in communication with the main passageway; and an intermediate portion disposed between the proximal end portion and the distal end portion, wherein the intermediate portion defines a side opening in communication with the main passageway and configured to receive and support a second blood vessel therein, wherein the main tubular body has a pair of longitudinal edges configured to be disposed adjacent one another when the main tubular body is in the closed configuration, the pair of longitudinal edges together defining a seam that extends along a length of the main tubular body, the seam and the side opening being disposed in opposing relation to one another; and the opening of the intermediate portion being formed by a looped filament positioned in substantially opposing or diametrically opposing relation with the longitudinal seam of the main tubular body. a proximal end portion defining an opening in communication with the main passageway; a distal end portion defining an opening in communication with the main passageway; and an intermediate portion disposed between the proximal end portion and the distal end portion, wherein the intermediate portion defines a side opening in communication with the main passageway and configured to receive and support a second blood vessel therein, wherein the main tubular body has a pair of longitudinal edges configured to be disposed adjacent one another when the main tubular body is in the closed configuration, the pair of longitudinal edges together defining a seam that extends along a length of the main tubular body, the seam and the side opening being disposed in opposing relation to one another; and the opening of the intermediate portion being formed by a looped filament positioned in substantially opposing or diametrically opposing relation with the longitudinal seam of the main tubular body.