The dynamics of the temperature field in a subcutaneous blood vessel subjected to laser radiation is calculated by a method similar to that used previously but taking into account the heat exchange at the interface between the bloodstream and surrounding tissues. The distribution function of heat sources is determined based on the solution of the problem of diffraction of electromagnetic radiation from a circular cylinder. Regimes of irradiation of skin required for blocking the bloodstream under corresponding medical indications are modeled. In this case, the optimal exposure times depend on the vessel diameters and, for radiation at a wavelength of 530 nm, vary from tens to hundreds of microseconds.