An endovascular system for deployment at branched arteries comprising: a chimney graft having a proximal portion with a proximal open end deployable within a main artery and an opposed distal portion with a distal open end deployable within a branch artery branched from the main artery; and a main tubular graft deployable within the main artery and comprising a proximal open end and an opposed open distal end, the proximal and distal ends defining a tubular graft wall therein between; wherein, when deployed, a proximal portion of the tubular graft wall spans the branch artery; and wherein, when deployed, the distal portion of the chimney graft is disposed within the branch artery; wherein, when deployed, the proximal portion of the chimney graft is disposed within the main artery such that the proximal end of the chimney graft is about adjacent to or extends beyond the proximal end of the main tubular graft; and characterized in that the endovascular system further comprising a gutter-sealing device as being a separate member from the chimney graft; wherein the gutter-sealing device comprises a second graft disposed over the proximal portion of the chimney graft, the second graft having a wall with opposed elongate atraumatic side portions; the gutter-sealing device is disposed about at least a portion of the proximal portion of the chimney graft; and where, during deployment, the second graft is circumferentially rotatable about the proximal portion of the chimney graft so that the second graft is alignable between the main tubular graft and the wall of the main artery to prevent flow of blood among the chimney graft, the main tubular graft and a wall of the main artery. a chimney graft having a proximal portion with a proximal open end deployable within a main artery and an opposed distal portion with a distal open end deployable within a branch artery branched from the main artery; and a main tubular graft deployable within the main artery and comprising a proximal open end and an opposed open distal end, the proximal and distal ends defining a tubular graft wall therein between; wherein, when deployed, a proximal portion of the tubular graft wall spans the branch artery; and wherein, when deployed, the distal portion of the chimney graft is disposed within the branch artery; wherein, when deployed, the proximal portion of the chimney graft is disposed within the main artery such that the proximal end of the chimney graft is about adjacent to or extends beyond the proximal end of the main tubular graft; and characterized in that the endovascular system further comprising a gutter-sealing device as being a separate member from the chimney graft; wherein the gutter-sealing device comprises a second graft disposed over the proximal portion of the chimney graft, the second graft having a wall with opposed elongate atraumatic side portions; the gutter-sealing device is disposed about at least a portion of the proximal portion of the chimney graft; and where, during deployment, the second graft is circumferentially rotatable about the proximal portion of the chimney graft so that the second graft is alignable between the main tubular graft and the wall of the main artery to prevent flow of blood among the chimney graft, the main tubular graft and a wall of the main artery.