Since the days of the triumvirate of aspirin, heparin, and warfarin, health care practitioners have attempted to blunt the response of the coagulation system. Use of CPB has enhanced our awareness of the effects that a foreign surface has on blood in general. Success in correcting or preventing life-threatening conditions caused by thromboembolic disease depends on having the ability to correct the condition as well as the ability to limit the body's response to the intervention. Knowing how the body responds to foreign surfaces is crucial, as is awareness of current methods to limit these responses. This approach will help ensure procedural success with fewer side effects and better overall patient outcomes.