Cardiovascular diseases from cardiovascular diseases to bovine pericardial tissue are one of the major causes of death in the world: the annual growth rate of cardiovascular diseases in China is 9.85%, and it is still on the rise. According to the "China Cardiovascular Health and Disease Report 2019", there are 330 million people suffering from cardiovascular diseases, and heart valves account for nearly 1/3 of the prevalence of cardiovascular diseases in China. In 2018, the number of patients with heart valve disease in China was 27.2 million, and the "White Paper on Cardiac Surgery and Cardiopulmonary Bypass Data in China" shows that with the deepening of the aging population, it is expected to reach 31.3 million in 2025.
The heart valve is the basic structure of the heart, which may cause death due to congenital or acquired inflammation and other diseases such as insufficiency (regurgitation) and stenosis of the valve. There are four main categories of valvular disease: aortic stenosis, aortic regurgitation, mitral regurgitation, and tricuspid regurgitation. For patients with severe valvular heart disease, replacement of artificial heart valves is the most effective treatment.
Artificial heart valves can be divided into mechanical valves made of pyrolytic carbon and biological valves made of cross-linked pericardial tissue from pigs and cattle. Mechanical valves are designed to last longer (50 + years), but are more prone to complications and require lifetime anticoagulants and testing for clotting function. The service life of the biological flap is shorter than that of the mechanical flap (10-20 years), and the advantage is that there is no long-term anticoagulant medication.
In Europe and the United States, more biological valves are used, reaching more than 75%. In the early years of China is dominated by mechanical valves. In recent years, with the development of biotechnology, the disadvantage of low durability of biological valves has been gradually overcome. Research data shows that the 20-year survival rate of bovine pericardial biological valves has reached more than 90%, which is much higher than that of mechanical valves, about 45%.
Among biological valve materials, bovine pericardial tissue has become the mainstream product in the European and American markets because of its best mechanical properties and longer durability than pig aortic valve. Used in cardiac surgery to replace diseased, damaged, malformed or previously implanted aortic, mitral and tricuspid valves.
From Bovine Pericardial Tissue to Laser Cleaning
Although pericardium has attracted much attention as a raw material, the fiber and fat inherent in bovine pericardium tissue can easily affect the function of the tissue itself. In addition, the extraction environment of pericardium is a common slaughterhouse environment, and the raw materials have various foreign dust adhering to the tissue fiber surface. The current removal method is manual removal, which is not only inefficient, but also easy to cause accidental injury of tissue pieces, and there is a certain rework rate.
The tissue thickness of the pericardium is about 0.3-0.4mm, and there are about 50um coarse fibers on the coarser side. Because the substrate is thin and the pollutants grow on the surface of the substrate, it is difficult to remove them by chemical or ultrasonic cleaning methods. At present, the manual production time of each valve takes about 12-18 hours, and most of them use artificial methods to remove the surface fibers bit by bit with tweezers and then sew, which is very low efficiency and the fiber removal effect is not good.
The pulsed laser cleaning equipment of Water Drop Laser can be applied to the removal of fibers on the surface of pericardial tissue. Laser cleaning is to use laser energy to penetrate the surface of the object so that the electron absorbs energy, transfers to the lattice to produce vibration, and produces a macroscopic temperature to vaporize pollutants at a time of 10 picoseconds, so as to achieve the purpose of cleaning. After cleaning, the surface of pericardial tissue was smooth, and there were no traces of burning and discoloration.
Biological tissues are being used more and more widely. However, the cleaning processes in the early production of such major biological tissue sources as bovine pericardial tissue, pig aortic valve or pig pericardial tissue are all similar. The way of manual treatment of surface fibers, foreign bodies and contaminated dust affects the production tempo and quality of products to some extent. Laser cleaning technology can make up for and improve the production efficiency of products in this respect.
From Laser Cleaning to Medical Devices
The application of bovine pericardial tissue is only one case of our application in the field of medical devices, in fact, medical devices have a broad application prospect of laser cleaning: from bovine pericardial tissue to corneal biological patches, from implant interventional medical devices to general clinical medical equipment, the demand for non-contact, high-precision cleaning is a huge market that needs to be filled.
For example, implanted interventional medical devices need to enter the human body, and safety and effectiveness are the core indicators of implanted interventional medical devices. Non-radioactive, non-toxic, non-polluting and good compatibility with the human body is the general choice of its materials, which requires that in the processing of implanted interventional medical devices, the intrinsic characteristics of the material need to be guaranteed, which means that the physical, chemical, and structural properties of the material can not cause adverse changes. Laser processing technology has gradually become the preferred technology for device processing in this respect.
Because laser cleaning has the advantages of non-contact pollution-free, micron-level processing scale, does not change the chemical or physical characteristics of the biological material itself, and does not damage the substrate. Compared with manual cleaning or chemical cleaning agents, it is more "clean" and more suitable for planting medical equipment such as interventional medical devices that have special requirements for cleaning.
In addition to artificial biological heart valves and various kinds of patches, other medical devices made by mechanical or biological tissues such as catheters, coronary artery stents, balloons, occluders for the treatment of congenital heart disease, dental implants and ceramic materials can be applied to laser cleaning.
At present, industrial cleaning methods such as ultrasonic cleaning and plasma cleaning have been widely popularized in the application of medical devices, and have become the "standard" of laboratory or clinical equipment. because the industrialization time of laser cleaning is too short, most people are still somewhat unfamiliar with it, and it has not been able to make a difference in the field of medical devices.
However, with the scientific research achievements of the corresponding disciplines gradually put into the market, I believe that laser cleaning will play a more important role in the production of more medical devices in the future.
Xi'an Guosheng Laser Technology Co., Ltd. is a high-tech enterprise specializing in R&D, manufacturing and sales of automatic laser cladding equipment, high-speed laser cladding equipment, laser quenching equipment, laser welding equipment and 3D printing equipment. Our Laser Welding Equipment is cost-effective and sold domestically and abroad. If you're interested in our products, please contact us at bob@gshenglaser.com.