Propofol cardioplegia for Myocardial Protection Trial: Prompt
During cardiac surgery the heart is isolated from the rest of the circulation (bypassed) and a heart-lung machine is used to oxygenate the blood and pump it around the body. The heart is stopped, and provided with nutrients, by a (cardioplegic) solution that is injected directly into the heart arteries from time-to-time. This allows the surgeon to operate on the heart while it is still and not filled with blood but looking after the heart in this way during the operation is not ideal. The heart muscle can become short of oxygen and, when the heart is restarted and blood starts to flow through the coronary arteries again, the muscle can be harmed. The damage is believed to be caused mainly by the formation of highly reactive molecules known as ‘free radicals’ in the heart muscle during the time it is short of oxygen.
Propofol is a general anaesthetic widely used in cardiac surgery and recent research suggests that propofol could protect the heart muscle against damage from free radicals. We wanted to investigate the benefit of adding propofol to the cardioplegic solution in patients having isolated coronary artery bypass grafting (CABG) or aortic valve replacement surgery (AVR) using the heart-lung machine.
We assessed the benefits of adding propofol by studying chemicals released by the heart and other organs in the body when they are damaged or stressed. We measured these chemicals in blood samples taken before, and after the operation, and in very small pieces of heart muscle obtained during the operation. Removing small pieces of heart muscle during surgery is a well established research procedure that has no effect on the heart.