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Biomedical Engineering

Vital implant

The first national stent produced by laser is going to reduce the cost of cardiac therapies

To dominate the technology for the production of coronary stents could lead Brazil to participate in the group of countries that manufacture these devices inserted into the veins or arteries by way of angioplasty surgery with the objective of unblocking them so that the blood flows normally. The first step for the national production of these prostheses was taken at the beginning of March at the Heart Institute (InCor) of Sao Paulo, with the placing of a stent in the artery of a rabbit. The small metal part was developed by the São Paulo company LaserTools, which produced it by way of laser beams. The procedure represents the start of a long process of clinical testing that will culminate with tests on human beings within approximately one year. Only then, should the results be satisfactory, will the device get the green light of the National Agency for sanitary Vigilance (Anvisa) for commercial use. “We are confident that this is going to happen to two to three years. Up until then we shall have to knock down some barriers”, says the physicist and researcher Spero Penha Morato, a partner at LaserTools. The manufacture of this implant is of major importance, because there is Brazil a demand to the order of 90,000 coronary stents per year and all of these devices are imported.

The manufacture of stents by LaserTools has made up part of the company’s objectives over the last seven years. “We have perceived the possibility of producing these bio-compatible metallic implants since the founding of the company in 1998”, says Morato. “But, in order to manage to develop the device, we had to create a network of partners, because the laser cut, which is our specialty, is only the first step in the manufacture of the product. After this comes the development phase for us to arrive at a stent the same as or even better than the imported models, which are coated with pharmacological products”, the researcher goes on. This coating serves to avoid the proliferation of scar tissue on the artery wall that can cause a new obstruction in the blood vessel, even with the presence of the stent.

Multidisciplinary team
The first partnership was established at the start of 2003 with the company called Scitech Medical, from Goiânia, which specializes in the commercialization of stents. “At the end of that year, when reading an article in the Pesquisa FAPESP magazine (Issue No. 94 of December 2003), I got to know about the work of professor Marcelo Ganzarolli de Oliveira, from the Chemistry Institute of the State University of Campinas (Unicamp), who had developed polymer films used for coating stents and I invited him into our group, which also included a team from InCor”,  Morato recalls. At that time, LaserTools had begun its second phase of the Small Business Innovation Technology (PIPE) program through FAPESP, directed exclusively to the creation of bio-compatible medical implants, such as coronary stents and peripherals (indicated for implanting in other arteries of the body), distracter (bone stretcher), titanium screen netting (serves for bone integration and are used in orthopedic and mandibular  surgery), clips for aneurism and spine implants, all of them cut using a laser. “The development of these devices gave origin to a new business unit, which ended up transforming itself into the company named Inovatech Medical, which will produce the stents”, affirmed researcher Morato. Just like LaserTools at the start of its history, Inovatech is located at the Technology Companies Incubator Center (Cietec), installed at University City in Sao Paulo.

Right from the first PIPE project , that began in 1998,  LaserTools has been developing laser processes for various segments of industry, as well as relief engravings. The stent and other biomedical products, nevertheless, have marked a new phase in the company. They are delicate products for implanting into the human body that require a meticulous production process. Each piece, measuring 18 mm) in length and 1.8 mm in breadth is cut in the form of a very fine metallic mesh netting made from a tube of stainless steel with special specifications. The thickness of the mesh wall is around 100 microns (1 micron is a one thousandth part of a millimeter) and the laser cuts for transforming the tubing into a mesh are done with a precision of 20 microns. After cutting, the stent is chemically immersed for the removal of oxidation that might appear during the production. The next stage consists of thermal treatment under high vacuum for relieving any tensions caused by the laser cut and also there is electro-polishing to give it a final finish. Finally the device passes through a sterilization process and is then ready to be implanted or to be recoated with a polymer coating.

The stent implanted in the rabbit in March at the InCor hospital is a simple steel model, without any type of coating. The device will remain for thirty (30) days on the rabbit’s artery, of caliber similar to that of a human coronary, and afterwards will be removed for evaluation. In the first phase of the tests, three different type of stent will be implanted in nine rabbits: steel without a coating, steel coated with a polymer and steel coated with a polymer embedded with drugs. Tests are also forecast with stents made with other metal alloys and with differentiated designs. Once the implants in the rabbits have been concluded, the next procedure will be to test the metallic sheeting in the coronary arteries of pigs. In these animals the stent evaluation is carried out six months after implanting.

Refined tests
These experimental stages, which should be up to a year in duration, are fundamental for the correct conducting, from the scientific point of view, of the development of this type of device. The studies on experimental animals, rabbits and then pigs, are very important for estimating the safety and efficiency of the device being tested. They also serve to refine the technology of the confectioning of devices under development.”, affirmed the medical doctor, Pedro Lemos, from the Hemodynamic and Intervention Cardiology Service of InCor, responsible for the implants. “Only after the animal study phase, when we have reached a conclusion in relation to the final format of the stent, is when we can begin to move to the phase of clinical tests on patients, which should last up to six months at the very minimum”, advised Dr. Lemos.

The cost of a national stent has as yet not been defined, but, according to researcher  Spero, when they are launched on the market they will be cheaper than similar imported models, which cost from R$ 4,5000.00 (steel model) to R$ 15,000.00 (with a drug coating). “The price is going to depend on the volume that are placed on the market”, affirmed the researcher who hopes to produce sufficient to attend to the national demand and to export to the neighboring countries of Mercosul and other countries.

The Project
Bio-compatible metallic implants (nº 02/02134-0); Modality Small Businesses Technological Innovation (PIPE) program; Coordinator Spero Penha Morato – LaserTools; Investment R$ 64,940.00 and US$ 133,510.00 (FAPESP)