Heart valve replacement refers to procedures aimed at replacing your own heart valve, rather than repairing your own valve. If a surgeon cannot repair a heart valve, the valve is removed and replaced with an artificial (prosthetic) valve by sewing it into the remaining tissue from the natural valve. Throughout the world, 95% of all valve replacements are performed for mitral or aortic valves. The mitral valve is positioned in the heart´s left side, between the left upper chamber (left atrium) and the left lower chamber (left ventricle). The aortic valve separates the left ventricle from the aorta (which carries blood to the body).
A mechanical valve is carefully designed to mimic the native heart valve. It has a ring, like your own natural heart valve, to support the leaflets. Like your own heart valve, the mechanical valve opens and closes with each heartbeat, permitting proper blood flow through the heart. To prevent any blood clots from developing on the valve, which can cause complications, a mechanical valve replacement requires you to take anticoagulation medicine (blood thinners) daily. The dosage of this medication is different for each person, so you will be closely monitored to make sure you are on the correct dosage for you. Regular blood tests will be performed at the physician's office, an anticoagulation clinic, or at home with a specialized testing kit.
The tissue valve is a native valve taken from an animal. Once the tissue is explanted (removed), it is chemically treated and prepared for human use. Some tissue valves have a frame, or stent, that supports the valve, and some valves are stentless (no framework). A very thin polyester mesh cuff is sewn around the outside of the valve for easier implantation. Eliminating the stent makes it possible for the surgeon to implant a larger valve. Larger valves generally provide more surface area for blood flow; this allows more blood to flow through the valve to accommodate the body's needs.
Homografts or Allografts
A homograft or allograft is a human valve obtained from a donor. This type of valve is particularly beneficial for pregnant women and children, because it does not require long-term anticoagulation therapy. In addition, it can provide excellent hemodynamic performance, allowing for natural function of the surrounding structures. Because the availability of these valves depends on donors, supply is limited.
What to Expect Before
For your heart valve surgery, a highly qualified team of medical personnel works together to ensure the safest possible procedure. An anesthesiologist will examine and talk to you about the surgery and medications that will be used during the procedure. A perfusionist will operate the heart-lung machine that keeps oxygenated blood circulating through the body while the heart is stilled so that surgery can be performed on it. There are other specialized surgical assistants and nurses that assist and closely monitor your condition.
Before the surgery, you will receive an intravenous (IV) line in your arm or hand. This will enable your doctor to administer medications and fluids. You will be asked to remove any jewelry, contact lenses or eyeglasses, hearing aids, and dentures. Your doctor will probably give you a mild sedative in your IV prior to the procedure.
Complications & Risks
With improvement in technology and surgical techniques, there has been continued reduction in complications associated with open-heart surgery. Still, every open-heart surgery entails some risk. Though rare, some of the potential complications include infection, bleeding, stroke, and heart attack.
Ask your physician if you have any questions about potential risks or if you have more questions about heart valve repair.
What to Expect During
You will be fully anesthetized before your heart surgery begins. The surgeon then will make an incision down the center of the chest, separating the breastbone in order to gain access to your heart. In order to operate on the heart, it must be still. To accomplish this, the heart-lung machine is used to take over the job of the heart and the lungs. A special tube is placed in your right atrium. This tube carries blood from the body to the machine, which oxygenates the blood. The machine then pumps the oxygenated blood through another tube that has been placed into the aorta to circulate the blood back through the body. The term bypass is often used to describe this method of bypassing the heart and lungs.
The surgeon then makes another incision in the heart or aorta and removes the damaged valve. The new replacement valve is properly positioned and sewn into place. The incisions in the heart are then closed (sewn); the heart-lung machine is withdrawn; and the heart is started again to circulate blood through the lungs and body. The breastbone is rejoined with wires and the incision closed.
The procedure outlined here is a conventional, open-chest procedure for valve replacement surgery. Recent technology has allowed surgeons to perform valve replacement or repair with less invasive techniques. This is not always an option and depends on whether the facility has the technology available. In some cases, the specific nature of the repair needed cannot be performed using the less invasive technology, and conventional surgery is required. The less invasive approach will most likely involve a shorter procedure time, reduced hospital stay, and quicker recovery.
What to Expect After
After surgery, you will be placed in the intensive care unit (ICU) where you can be continuously monitored. Breathing during surgery, and for a while afterwards, is assisted through a tube that has been placed down your throat and positioned in your lungs. You will probably wake up with this tube still in position. It is removed as soon as you are stable and awake enough to breathe on your own. You will not be able to talk while this tube is in place. Other tubes will protrude from your chest near the heart to drain extra blood and fluid from the surgical area. Intravenous lines give fluid, blood, and medications as needed. A bladder catheter drains urine. A monitor shows the heart rate, heart rhythm, blood pressure, and other special pressures and waves that the nursing staff watches closely to assess how the recovery is going. Medications are given as needed to ease pain and anxiety.
Every patient recovers at a different rate. Tubes are removed as recovery progresses. The ICU stay is usually a day or two. Then you will be moved to a cardiac medical-surgical floor where your heart is still continually monitored, but you can be more independent and active. The health care team continues to support and instruct you in recovery care, rehabilitation, medications, nutrition, and other needs.