Applying a degradation model to describe corrosive behavior in biodegradable stents to explain its influence in mechanical properties

Abstract

Cardiovascular diseases are considered the most common cause of death in the entire world. One of the main pathological processes that lead to coronary heart disease is known as atherosclerosis. It consists of an inflammatory process affecting medium to large blood vessels in the human body. Nowadays, treatment is typically site-specific, and the preferred method depends on the level and extent of the occlusion, also called stenosis. The development of intravascular metal stents in the last decade has increased the quality of life of patients suffering from congenital heart disease and coronary interventions. Stent technology can be classified as permanent or temporary stents. Despite their benefits, permanent metallic stents can cause long-term endothelial dysfunction, delayed reendothelialization, thrombogenicity, mismatch of the stent to the vessel size, artifacts with modern imaging techniques, and permanent physical irritation, which in turn, can cause arterial rupture or the formation of an aneurysm. Thus, research focused on designing temporary scaffolding devices to prevent these adverse effects. The development of biodegradable stents must ensure the stabilization of the vessel wall during the healing process, and, after its dissolution, the vessel must stay intact without a foreign body and with its full capacity of vasodilation. The biggest asset of this type of stents is that they disappear after a defined period of time once the vessel is healed. Depending on the patient, the scaffolding effect is required to last for approximately six to twelve months for the vessel to heal and remodel itself. After this period of time, the stent can be harmful, and it must be removed. Research is focusing on the development of biodegradable stents that must meet three main characteristics: biocompatibility, maintained mechanical properties and scaffolding feature during a period of time and controlled degradation rate. Material characteristics, bulk, and surface properties are all major characteristics to consider in the design of a new stent. These materials must be strong enough, with certain mechanical and chemical properties to guarantee their optimal function. Based on this argument, new stent technology is focused on keeping developing BDS to improve their performance by modifying their degradation rates to ensure their scaffolding feature is maintained for as long as the tissue heals itself. Thus, it is essential to understand how biomaterials behave during a degradation process to describe their corrosion behavior after implantation and maintain their structural properties until the tissue is completely healed.