Mechanical Mitral Valve. They are made of materials such as plastic , metal and the latest models consist of a small pyrolytic carbon cylinder. The pyrolytic carbon is graphite bombarded with atoms of carbon at high temperatures, a material almost as hard as diamond . It is very little thrombogenic (not very likely to produce clots or strokes ) and begins to show wear after an equivalent of 80 years of operation. However, over time, these prostheses become clogged, which is why patients need to take daily, and indefinitely,oral anticoagulants . In general they have a useful life of 20 to 30 years.
[ hide ]
- 1 Use
- 2 Substitution
- 3 Main problems
- 4 Risks of treatment
- 5 benefits
- 6 How the Surgery is performed
- 7 General care
- 8 Sources
When heart valves become sick, two types of injuries occur: narrowing or melting of the valve (stenosis), which makes it difficult for the valve to open and the passage of blood , and insufficiencies or defective valve closure that causes blood to flow in wrong address. Some injuries cause early suffocation and fatigue ( mitral stenosis ) but others only give symptoms in very advanced stages of the disease ( aortic stenosis). The surgical repair of a valve implies its reconstruction, so that it works correctly or its replacement by a valve prosthesis. Surgery is recommended in people who have significant symptoms that prevent a reasonable life for their age or in symptomatic patients whose life is short-term due to the nature of the injury.
They are replaced in congenital heart diseases that produce valve deformities from fetal life; in injuries caused by rheumatic fever (generally infantile and as a consequence of poorly healed angina), they cause mitral valve disease , which is only replaced by a prosthesis when it cannot be repaired (most cases of stenosis mitral or double mitral injury, as well as valve insufficiencies that cannot be repaired)
Problems depend on the type and location of the valve. In general, mechanical valves cause more problems than biological ones:
- Clot formation – can break and cause an obstruction (arrest) to blood flow somewhere in the body; They can also cause valve blockages.
- Problems derived from anticoagulation (prevents formation of clots): it can promote heavy bleeding.
- The valves can become infected ( endocarditis ): formation of small vegetations on the valve that can break or block the valve.
- They may leak or block due to the presence of scar tissue.
- It can damage red blood cells ( blood cells) causing hemolytic anemia (breakdown of red blood cells).
Wearers of cardiac prostheses, both mechanical and biological, should then continue under the supervision of a cardiologist, to control anticoagulation, avoid or treat infections that may settle in the prosthesis, and to follow the evolution of the prosthesis and the heart.
A study by researchers at Stanford University School of Medicine shows that for patients undergoing mitral valve replacement, a mechanical valve is beneficial until age 70. On the other hand, for patients undergoing aortic valve replacement, the benefit of implanting mechanical valves ceased after age 55. Mechanical valves can last a lifetime, but they present an increased risk of blood clots and bleeding, and a lifetime of taking warfarin, a blood-thinning medication. The biological valves, which are most often made from pig or cow tissue, do not increase the risk of bleeding or clots, but wear out in approximately 10 to 15 years, making a second surgery likely.
How is surgery performed
Once the heart has stopped, an incision is made in the left atrium (atriotomy) to access the valve, and the mitral valve is removed. The implant of the prosthesis (usually mechanical), as in the aortic position, is performed with non-absorbable points. Once the prosthesis is sutured, the atriotomy is closed and the function of the heart is restarted. Once the valve has been replaced, it is verified that the heart beats properly and is disconnected from the extracorporeal circulation. Subsequently, adequate hemostasis is performed (check and cancel all possible bleeding points), the drainage tubes are inserted and an external pacemaker cable is implanted. This cable can be connected to an external pacemaker generator if necessary; for example, if the heart beats too slowly during the postoperative period. Lastly, it is performed in closure of the sternum, and suturing of the subcutaneous cell tissue and skin. Finally, the patient is transferred to the Intensive Care Unit. After the operation, the patient usually goes home a week if there have been no complications.
All carriers of a heart valve prosthesis should take an antibiotic prior to those situations that facilitate the passage of bacteria into the blood, such as dental manipulations, genitourinary, colonoscopies, etc. This is essential to prevent endocarditis infectious