A reperfusion catheter system , comprising: an introducer sheath having an inner wall defining a longitudinal opening extending from a proximal portion to a distal end; a balloon catheter having an outer wall and having a longitudinal opening extending from a proximal end to a distal end, the balloon catheter disposed through the opening in the introducer sheath, the balloon catheter having an inflatable balloon at the distal end; a conduit having a first end disposed in fluid communication with the area inside the introducer sheath between the inner wall of the introducer sheath and the outer wall of the balloon catheter and having a second end disposed in fluid communication with the inside of the balloon catheter; and a valve system disposed between the conduit and the balloon catheter, wherein the valve system comprises a side port ; wherein the system is configured such that in use an antegrade blood flow is established in a lumen of a target vessel through a path between the outer wall of the balloon catheter and the inner wall of the introducer sheath, through the conduit, through the opening in the balloon catheter, and exiting through the distal end of the balloon catheter; characterised in the system further comprising: a micro catheter disposed through the opening in the balloon catheter; and a lateral check flow positioned in the proximal portion of the introducer sheath, wherein the lateral check flow includes a stopcock and wherein the conduit comprises a connecting tube extending between the stopcock and the side port of the valve system. an introducer sheath having an inner wall defining a longitudinal opening extending from a proximal portion to a distal end; a balloon catheter having an outer wall and having a longitudinal opening extending from a proximal end to a distal end, the balloon catheter disposed through the opening in the introducer sheath, the balloon catheter having an inflatable balloon at the distal end; a conduit having a first end disposed in fluid communication with the area inside the introducer sheath between the inner wall of the introducer sheath and the outer wall of the balloon catheter and having a second end disposed in fluid communication with the inside of the balloon catheter; and a valve system disposed between the conduit and the balloon catheter, wherein the valve system comprises a side port ; wherein the system is configured such that in use an antegrade blood flow is established in a lumen of a target vessel through a path between the outer wall of the balloon catheter and the inner wall of the introducer sheath, through the conduit, through the opening in the balloon catheter, and exiting through the distal end of the balloon catheter; characterised in the system further comprising: a micro catheter disposed through the opening in the balloon catheter; and a lateral check flow positioned in the proximal portion of the introducer sheath, wherein the lateral check flow includes a stopcock and wherein the conduit comprises a connecting tube extending between the stopcock and the side port of the valve system. a micro catheter disposed through the opening in the balloon catheter; and a lateral check flow positioned in the proximal portion of the introducer sheath, wherein the lateral check flow includes a stopcock and wherein the conduit comprises a connecting tube extending between the stopcock and the side port of the valve system. <EOS>