The objective of this study is to verify, through a randomized, single-blind, multicentre, parallel and comparative study, the effectiveness of heparin sodium of porcine origin in patients undergoing heart surgery that require the aid of cardiopulmonary bypass. The effectiveness will be determined through the control of hemostasis during and after surgery, based on the strengths of markers of coagulation trichloroacetic acid (TCA), alpha-tocopherol transfer protein (TTPA), Anti-Xa, heparin bioavailability and excessive loss of blood (bleeding) at the end of the surgery.