 The survival rates steadily increased from a few hours to several weeks, and one of the dogs that received a heart transplant in 1953 survived for another seven years after the operation.A successful mammary–coronary artery anastomosis was achieved in 1953, after unsuccessful attempts the previous year.Demikhov also developed the principles of myocardial revascularization, which enabled him to perform the first experimental coronary artery bypass operation.