Author : Ming H. Wu,Hengchu Cao
Publisher : Elsevier Inc. Chapters
Release : 2013-03-12
ISBN : 0128071052
Language : En, Es, Fr & De
Book Description :
The cardiovascular system consists of the heart and the vasculature. The physiology of the system is to circulate blood through the vasculature ensuring delivery of oxygen and vital nutrients to cells and organs in the body. Consequences of diseases disrupting normal cardiovascular function can be severe or fatal. Recent advancements in cardiovascular medicine have contributed significantly to improving life span and quality for patients by restoring normal cardiovascular function through the use of implantable devices. Examples of these cardiovascular implantable devices include endovascular stents, embolic protection devices and filters, closure devices, heart valve prostheses, cardiac rhythm management devices, such as pacemakers and defibrillators, and left ventricular assist devices. The main objective of this chapter is to provide an overview of device test methods commonly used in the development process from concept to commercialization of implantable cardiovascular devices. It is recognized that general device testing methodology and understanding for developing these cardiovascular devices can be extended to other devices as well as new product concepts under development. Developments of new medical devices are closely regulated by regulatory agencies. U.S. and international regulatory requirements for medical devices and drugs provide specific guidance for bench-top in vitro testing, in vivo animal study, clinical research, manufacturing, sterilization, and post-market surveillance for various device categories. Implantable cardiovascular devices generally fall within the Class II and Class III categories. Commercialization of these products in the United States requires FDA's Premarket Notifications (510Ks), Premarket Approvals (PMAs), or Exemptions. The design control element in the new product development procedure requires detailed documentation of design inputs and outputs as well as rational design verification through testing to ensure device functions and safety. Notably, implantable cardiovascular devices are subjected to very high safety expectation. The inability to perform periodic inspection and repair after device implantation also means that the statistical reliability and safety for these devices must be well established and verified prior to clinical uses. To facilitate discussions, a brief overview of the cardiovascular anatomy and physiology is provided in the beginning of this chapter. Following this overview are sections reviewing exemplary implantable devices used for treating various cardiovascular disorders. The majority of this chapter is then devoted to descriptions of necessary engineering characterizations and design verification test methods most relevant to developing cardiovascular devices for commercialization. Particular emphasis is placed on the attributes that are significantly affected by the biomaterials used in the designs. These include physical properties, such as the transformation temperatures for nitinol self-expanding devices, mechanical properties, structure integrity and durability, corrosion risk assessment as well as functional testing. In addition, biocompatibility testing refers to a battery of testing used to evaluate the biological reaction of the human body to the implanted device. There is a well-recognized ISO standard that governs the specific test protocol requirements (ISO 10993). Safety evaluation studies (in vitro and in vivo) are conducted on a variety of biomaterials, medical devices, and related products to identify the presence of toxins or any other potentially harmful effects. Common assessments of device imaging are also briefly described. These include radiopacity as well as magnetic resonance imaging (MRI) safety and compatibility.