Replacing a valve in the heart involves open heart surgery. First the surgeon saws through the patients sternum
to expose the heart. Then, the surgeon places a cannula
into the aorta
and connects the cannula to the heart lung machine. Then a second cannula is placed into the right atrium
of the heart. this cannula is used to draw blood away from the heart and towards the heart lung machine. The blood then travels through an oxygenator so that the blood can be oxygenated. (Thus the name heart-lung machine). Then the blood travels back towards the patient through the aortic cannula and through the patients body. Then the heart is stopped using a cardioplegia solution that contains a high concentration of potassium. The heart-lung machine delivers this solution to the heart and causes the heart to stop beating. The heart-lung machine continues to circulate the blood to keep the patient alive. The surgeon then opens the heart and replaces the valve with either a mechanical valve or a tissue valve. Then heart is the closed up, the heart is allowed to start beating again and then the person is weaned off the heart-lung machine.
The risks are death, stroke
and organ failure. However, these surgeries are done routinely and with considerable success. The surgery from start to finish is about 3-5 hours.