The present disclosure relates to a PTA (percutaneous transluminal angioplasty) balloon catheter, preferably high pressure type, optionally introducible as an over the wire catheter. The catheter possess the attribute of injecting fluid to the treated site through a dedicated opening proximal to the balloon member, for introduction of fluids such as contrast enhancing material and/or medication. In some embodiments, a single lumen is used, at least in part, both for fluids transfer and dispersion (“infusion”) as well as for guide wire passage. In some such embodiments, a valve mechanism is used to sustain selective operability of the lumen so that fluids will disperse mostly or solely through the proximal dispersion opening rather than the guide wire distal exit opening.