Mitral valve replacement - AbsoluteAstronomy.com

Mitral valve replacement is a cardiac surgery

Cardiac surgery

Cardiovascular surgery is surgery on the heart or great vessels performed by cardiac surgeons. Frequently, it is done to treat complications of ischemic heart disease , correct congenital heart disease, or treat valvular heart disease from various causes including endocarditis, rheumatic heart...

procedure in which a patient’s mitral valve

Mitral valve

The mitral valve is a dual-flap valve in the heart that lies between the left atrium and the left ventricle...

is replaced by a different valve. Mitral valve replacement is typically performed robotically

Robotic surgery

Robotic surgery, computer-assisted surgery, and robotically-assisted surgery are terms for technological developments that use robotic systems to aid in surgical procedures....

or manually, when the valve becomes too tight (mitral valve stenosis) for blood to flow into the left ventricle

Ventricle (heart)

In the heart, a ventricle is one of two large chambers that collect and expel blood received from an atrium towards the peripheral beds within the body and lungs. The Atria primes the Pump...

, or too loose (mitral valve regurgitation) in which case blood can leak into the left atrium and back up into the lung

Lung

The lung is the essential respiration organ in many air-breathing animals, including most tetrapods, a few fish and a few snails. In mammals and the more complex life forms, the two lungs are located near the backbone on either side of the heart...

.

A mitral valve replacement/repair is performed to treat severe cases of mitral valve prolapse

Mitral valve prolapse

Mitral valve prolapse is a valvular heart disease characterized by the displacement of an abnormally thickened mitral valve leaflet into the left atrium during systole. There are various types of MVP, broadly classified as classic and nonclassic. In its nonclassic form, MVP carries a low risk of...

, heart valve stenosis

Heart valve stenosis

Heart valve stenosis may refer to:* Mitral stenosis* Aortic valve stenosis...

, or other valvular diseases. Since a mitral valve replacement is an open heart surgical procedure, it requires placing the patient on cardiopulmonary bypass to stop blood flow through the heart

Heart

The heart is a myogenic muscular organ found in all animals with a circulatory system , that is responsible for pumping blood throughout the blood vessels by repeated, rhythmic contractions...

when it is opened up.

Options

Some surgeons will first recommend repairing the valve instead of replacement, but if the patient is not a good candidate for repair, then the valve should be replaced.

Many mitral valves can be repaired, especially if the leak is due to wear and tear. When the valve is too damaged to repair, the valve must be replaced with an artificial valve. There are some advantages to repairing a mitral valve versus replacing it. Some of these advantages are: a lower mortality at the time of operation (1-2% for repair versus 6-8% for replacement), a significantly lower risk of stroke

Stroke

A stroke, previously known medically as a cerebrovascular accident , is the rapidly developing loss of brain function due to disturbance in the blood supply to the brain. This can be due to ischemia caused by blockage , or a hemorrhage...

, a lower rate of endocardial infection, and improved long-term survival. Patients who receive a valve repair stay on the same survival curve as the normal population. After mitral valve repair, blood thinners are not required; however, life-long maintenance on blood thinners is required after mechanical mitral valve replacement.

Non-Surgical Options

Most patients can endure surgery without complications; however, there are some whose heart functions are too weak to withstand surgery. Non-surgical approaches to treat heart valve disease without surgery are divided into three categories: Clinical Practice treatment (this is used in every day clinical practice), Investigational treatment (current clinical studies that are underway), Early Development treatment (early stages of investigation).

Types of Valves

There are two primary types of artificial mitral valves—a metal or mechanical valve and a tissue valve or biological valve. The mechanical valves are made entirely from metal and pyrolytic carbon

Pyrolytic carbon

Pyrolytic carbon is a material similar to graphite, but with some covalent bonding between its graphene sheets as a result of imperfections in its production....

and last a lifetime. With this valve, patients are required to take blood-thinning medications to prevent clot

Thrombus

A thrombus , or blood clot, is the final product of the blood coagulation step in hemostasis. It is achieved via the aggregation of platelets that form a platelet plug, and the activation of the humoral coagulation system...

ting. The tissue valve is made from animal tissues. The tissue valve doesn’t require a patient to take blood thinners, but it only lasts 10 to 15 years.
The choice of which type to use should be made by the patient and his doctors taking the following into consideration: patient's age, medical condition, preferences with medication, and lifestyle.

Details of the procedure

A mitral valve replacement procedure is performed under general anesthesia, which will keep the patient asleep during the whole surgery. The preferred method is to first make an incision under the left breast

Breast

The breast is the upper ventral region of the torso of a primate, in left and right sides, which in a female contains the mammary gland that secretes milk used to feed infants.Both men and women develop breasts from the same embryological tissues...

rather than through the breastbone in the front of the chest

Chest

The chest is a part of the anatomy of humans and various other animals. It is sometimes referred to as the thorax or the bosom.-Chest anatomy - Humans and other hominids:...

, to get to the heart. After the heart is exposed, blood must be rerouted to a heart-lung machine

Heart-lung machine

Cardiopulmonary bypass is a technique that temporarily takes over the function of the heart and lungs during surgery, maintaining the circulation of blood and the oxygen content of the body. The CPB pump itself is often referred to as a heart–lung machine or "the pump"...

(cardiopulmonary bypass). An incision is made in the left atrium to expose the mitral valve. The valve is then replaced with either a biological or mechanical valve. Then after the functioning of the new valve is tested and confirmed, the heart is then closed with sutures. The patient is then taken off the cardiopulmonary bypass and blood is allowed to flow into the coronary arteries. If the heart does not beat on its own, an electric shock is used to start it. Then the chest is closed up..

Risks

With mitral valve replacement surgery, there are risks such as bleeding, infection or a complicated reaction to anesthesia. Each risk is determined best with each patient's own cardiologist and cardiothoracic surgeon. They will better know each individual's medical history and conditions. Risks depend on a patient’s age, general condition, specific medical conditions, and heart function.

Postoperative Complications/ Risks

A common postoperative complication with mitral valve surgery in a study involving 99 patients who had surgery for mitral regurgitation from January 1990 to June 1996 is atrial fibrillation

Atrial fibrillation

Atrial fibrillation is the most common cardiac arrhythmia . It is a common cause of irregular heart beat, identified clinically by taking a pulse. Chaotic electrical activity in the two upper chambers of the heart result in the muscle fibrillating , instead of achieving coordinated contraction...

. This occurred in 32% of patients. A common pulmonary complication is congestion necessitating prolonged use of oxygen

Oxygen

Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...

. Other patients required prolonged ventilation of longer than 24 hours for conditions like pulmonary edema

Pulmonary edema

Pulmonary edema , or oedema , is fluid accumulation in the air spaces and parenchyma of the lungs. It leads to impaired gas exchange and may cause respiratory failure...

, ARDS, and pulmonary thromboemboli. Nine patients had renal failure

Renal failure

Renal failure or kidney failure describes a medical condition in which the kidneys fail to adequately filter toxins and waste products from the blood...

with six of them dying within 30 days after their operation. Five patients had permanent strokes, and nine patients were readmitted to the hospital within 30 days of their discharge.

Effectiveness

In a clinical study done of 99 patients who had mitral valve surgery for regurgitation from January 1990 to June 1996, long-term and short-term outcomes were evaluated. These evaluations included; mortality rate

Mortality rate

Mortality rate is a measure of the number of deaths in a population, scaled to the size of that population, per unit time...

, clinical complications, readmissions, valve deterioration, reoperation, and health perception. Overall mortality was 4%, which included 3 operative deaths and 4 late deaths. Overall 5-year survival rate was 92%.

Condition after mitral valve replacement

After the surgery the patient is taken to a post-operative intensive care unit for monitoring. A respirator

Medical ventilator

A medical ventilator can be defined as any machine designed to mechanically move breatheable air into and out of the lungs, to provide the mechanism of breathing for a patient who is physically unable to breathe, or breathing insufficiently....

may be required for the first few hours or days after surgery. After a day, the patient should be able to sit up in bed. After two days, the patient may be taken out of the intensive care unit. Patients are usually discharged after about seven to ten days. If the mitral valve replacement is successful, patients can expect to return to their regular condition or even better. Patients who have biological valve are prescribed blood thinners (Anticoagulation) with warfarin

Warfarin

Warfarin is an anticoagulant. It is most likely to be the drug popularly referred to as a "blood thinner," yet this is a misnomer, since it does not affect the thickness or viscosity of blood...

for 6 weeks to 3 months postoperative, while patients with mechanical valves are prescribed blood thinners for the rest of their lives. These blood thinners are taken to prevent blood clots that can move to other parts of your body and cause serious medical problems, such as a heart attack. Blood thinners will not dissolve a blood clot but they prevent other clots from forming or prevent clots from becoming larger. Once the patient’s wounds are healed they should have few, if any, restrictions from daily activities. Patients are advised to walk or undertake other physical activities gradually to regain strength. Patients who have physically demanding jobs will have to wait a little longer than those who don’t. Patients are also restricted from driving a car for six weeks after the surgery. Once a person has a mitral valve procedure, they are required to have prophylactic antibiotics as a preventative measure against infection whenever they have dental work done.

Depending on the method of surgery, some scarring will occur. If the breastbone is divided, the patient will have a long scar along the breast bone. If the heart is accessed from under the left breast there will be a smaller scar in the spot.

External links

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