One is mechanical valve, and the other is biological valve.
The former is made of advanced synthetic materials, while the latter is made of advanced synthetic materials and biological tissue membranes through complex chemical treatment. Each has its advantages and disadvantages. The advantage of mechanical valve is good durability, but the disadvantage is that it needs lifelong anticoagulation, and the thromboembolism rate is higher than that of biological valve. The latest research abroad also suggests that mechanical valves may have better performance than biological valves if they are used for a long time. The advantages of biological valve are that anticoagulation is not needed for life after operation, and the thromboembolism rate is low, which improves the quality of life of patients. Therefore, biological valves can be used for patients who cannot receive anticoagulation treatment due to bleeding factors and patients who are inconvenient for anticoagulation in rural and remote areas. Their disadvantage is that they are not as durable as mechanical valves, and the life of valves is about ten years. If it is damaged, it needs to be replaced for the second time. As for which valve is suitable for you, the doctor will recommend it to you according to the condition. Now, the various artificial heart valves that can be selected in clinic are briefly introduced as follows:
1. Biovalves Biovalves include autologous pulmonary valve, allograft aortic valve, xenograft aortic valve and bovine pericardium xenograft biovalves. Autologous pulmonary valve is to remove the patient's own pulmonary valve and immediately replace the damaged aortic valve, and replace the pulmonary valve with other homograft valves to ensure the normal function of the aorta. This operation is complicated and not widely used. The allogenic aortic valve is taken from fresh corpses that died of other causes, and the effect is also good. Cryopreservation with liquid nitrogen can be preserved for a long time, but it can only be used for aortic valve replacement because of the limitation of source and the characteristics of no stent. At present, the application of the same biological valve is not as much as that of the heterogeneous biological valve. Heterogeneous biological valves include pig biological valves, bovine pericardial valves and equine pericardial valves. Among them, pig biological valve is widely used, but its clinical effect is obviously not as good as that of bovine pericardial biological valve. At present, the latest research direction of biological valves abroad is to implant biological valves (such as Sorin Percival) by minimally invasive technology, which makes the valve replacement operation simpler, reduces the trauma of patients and effectively reduces the risk of surgery. Brief introduction of common biological valves is as follows:
1, Hancock valve The porcine aortic valve treated with 0.2% glutaraldehyde is embedded in the metal stent, which is inelastic and the seat ring is round. A part of muscle tissue attached to the right lobe affects the effective area of the valve orifice. Subsequently, a compound trilobal valve without muscle tissue was used. Hancock's improved model 250 is a combined valve and adopts an elastic frame, so the effective valve opening is obviously expanded.
2.Carpentier-Edwards valve: It is the most widely used biological valve in the world. The valve frame is made of elastic alloy steel wire and covered with sparse polyester cloth. The non-circular seat ring makes it close to the attachment edge of the valve leaflet, which reduces the space occupied by the inferior muscle tissue of the right valve leaflet in the valve orifice, and the effective valve orifice area is also larger.
3. Complete valve: It is characterized in that during glutaraldehyde treatment, the valve leaves are not subjected to any tension, and after drug fixation, the elastic structure in the valve leaves still keeps tight wavy arrangement and does not become straight. This is called tension-free fixation to increase the durability of leaflets. In addition, treatment measures to prevent calcification have been taken. From 1983 to 1987, 930 pieces have been implanted in clinic, and the effect is good.
4. Ionescu Healy Flap: Ionescu was first created in 197 1 year. This valve was made of calf pericardium from June to 65438+August. Fixed with glutaraldehyde solution, the whole bovine pericardium slice with uniform thickness was selected and wrapped around the stent to make three equal lobules. Elastic low valve frame, hydrodynamic test and fatigue test are better than pig aortic valve. Beijing BN valve: The bovine pericardial valve produced by Fuwai Hospital is similar to the standard Ionescu valve and was put into clinical use on 1976. Up to 1987, more than 800 flaps have been implanted clinically. 10 years follow-up showed that the valve intact rate was 74.5%. At present, there are many bovine pericardial valves in the international market, such as Mitroflow, Edwards, Sorin and so on. , in the prevention of calcification has been significantly improved.
⒌ Sorin Mitroflow valve and Solo valve: 1985 The first generation Sorin bovine pericardial biological valve was introduced and applied in clinic, and it was treated with glutaraldehyde. After 15 years of clinical research abroad, its hemodynamic performance is satisfactory. The latest Mitroflow and Solo valves have been detoxified, which has avoided the toxicity of glutaraldehyde to heart tissue, effectively prevented the calcification of the valves, and obviously improved the durability of the valves. Among them, Mitroflow adopts valve frame design, which makes implantation easier. Solo is a valveless valve with good hemodynamics and postoperative clinical effect.
At present, there are two kinds of mechanical valves: single valve and Shuang Ye valve. Because the hemodynamic performance of Shuang Ye valve is obviously superior to that of single-lobe valve, the single-lobe valve has basically withdrawn from clinical use. Representative are:
1 and Shuang Ye mechanical flap of St. Jude: the blade is thin and rectangular, made of pyrolytic carbon, and both ends of the blade slide in the chute of the valve ring. When the valve hole is opened, the blade reaches above 80℃, almost parallel to the blood flow. Therefore, it can also be considered as a central blood flow mechanical valve. Its hydrodynamic performance is better than that of swashplate mechanical valve.
2. Medtronic ATS Shuang Ye mechanical valve: The valve frame design highlights the ball axis, which originated from the original Carbomedics Company (now Sorin Company). The clinical manifestations are similar to those of St. Jude's mechanical valve. However, due to its ball axis design, the incidence of thrombosis may be higher than other similar valves.
3. Sorin Shuang Ye mechanical valve: there are two series of carbon medical and bicarbonate. Carbomedics has been used in clinic for more than 25 years, and the number of implants in the world has exceeded 600,000. There is no structural failure in 1 case. Bicarbonate series adopts streamlined leaflet and stent design, which can effectively reduce the nozzle resistance and improve the postoperative effect. At the same time, due to the patented carbon plating technology, the durability of the valve is improved. The clinical data of 10 years show that the incidence of postoperative complications is lower than that of similar products.
4.On-X Shuang Ye mechanical valve: This product is made of pure non-alloy pyrolytic carbon, and its surface is covered with graphite hydrolysate. The valve plate hydrolysate is filled with 10% tungsten, the outer ring is titanium alloy, and the sewing ring is polytetrafluoroethylene. On-X valve has a unique design. Pure pyrolytic carbon has good biocompatibility, smoother surface and stronger antithrombotic effect. When the leaves are opened at 90℃ and parallel to the blood flow, the effective orifice area increases and the turbulence decreases, and the valve shaft is thoroughly washed to prevent thrombosis, which greatly improves the clinical effect. According to FDA statistics, compared with other valves, On-X valve can reduce the incidence of adverse events by 50-60%. Therefore, On-X, as the first and only heart valve product, was approved by FDA in June 2006 to conduct a multi-center (40 centers) clinical trial of anticoagulant effect of artificial heart valves: PROACT research for short. On-X valve is the result of research and application of pyrolytic carbon by Dr. Jack Bokros and his team for more than 40 years. Dr. Jack Bokros, the discoverer of pyrolytic carbon, was awarded the Lifetime Achievement Award of Biomaterial Surface Science Foundation in recognition of his contribution to promoting the development of isotropic pyrolytic carbon materials.