A medical balloon catheter device configured for use with a wire guide, the catheter comprising: an elongate monolayer multifilar tube, said tube comprising a proximal tube end, a distal tube end, and a longitudinal tube lumen extending therebetween; a dual-lumen sleeve structure disposed adjacent the distal tube end, said dual-lumen sleeve structure comprising a first sleeve lumen and a second sleeve lumen; and an inflatable balloon comprising a balloon lumen, said balloon lumen being in fluid communication with the tube lumen; wherein the first sleeve lumen comprises a wire guide lumen and extends distally beyond the distal tube end; wherein the second sleeve lumen comprises a tube-bonding lumen through which is disposed a tube portion adjacent the distal tube end; wherein a proximal portion of the balloon is connected to the tube and the sleeve structure, and is connected distally to the sleeve structure such that at least a portion of the sleeve structure extends through the balloon lumen; wherein the first sleeve lumen extends distally beyond a distal end of the balloon; wherein a wire guide aperture is disposed on a proximal portion of the wire guide lumen and is configured to provide passage therethrough for a wire guide; and wherein to provide additional protection against cross-lumen leakage in the region of the wire guide aperture, a barrier sleeve is provided around the circumference of the tube along a tube region adjacent the wire guide aperture, characterised in that a coating covers substantially the exterior surfaces of the tube and the sleeve structure, and provides a patent fluid communication path along the tube lumen between the proximal tube end and the balloon lumen. an elongate monolayer multifilar tube, said tube comprising a proximal tube end, a distal tube end, and a longitudinal tube lumen extending therebetween; a dual-lumen sleeve structure disposed adjacent the distal tube end, said dual-lumen sleeve structure comprising a first sleeve lumen and a second sleeve lumen; and an inflatable balloon comprising a balloon lumen, said balloon lumen being in fluid communication with the tube lumen; wherein the first sleeve lumen comprises a wire guide lumen and extends distally beyond the distal tube end; wherein the second sleeve lumen comprises a tube-bonding lumen through which is disposed a tube portion adjacent the distal tube end; wherein a proximal portion of the balloon is connected to the tube and the sleeve structure, and is connected distally to the sleeve structure such that at least a portion of the sleeve structure extends through the balloon lumen; wherein the first sleeve lumen extends distally beyond a distal end of the balloon; wherein a wire guide aperture is disposed on a proximal portion of the wire guide lumen and is configured to provide passage therethrough for a wire guide; and wherein to provide additional protection against cross-lumen leakage in the region of the wire guide aperture, a barrier sleeve is provided around the circumference of the tube along a tube region adjacent the wire guide aperture, characterised in that a coating covers substantially the exterior surfaces of the tube and the sleeve structure, and provides a patent fluid communication path along the tube lumen between the proximal tube end and the balloon lumen.