Fractional flow reserve (FFR) is known as a gold standard to measure the functional significance of coronary lesions and to distinguish significant lesions from non-significant ones. Simplified models of coronary circulation are used in deriving clinically used FFR and several factors such as collateral flow, coronary pressure-flow relationship and vessel distensibility are ignored. These simplifying assumptions are not always justified and are believed to affect the traditional haemodynamic indices such as FFR. It is shown that there is a link between vessel distensibility, remodeling and coronary artery diseases; however, the correlation between vessel distensibility and FFR is still unknown.
Nowadays with the development of the economy and technology, humans pursue various material or mental comforts frequently. The standard of living is a social-economic indicator which reflects people’s quality of life (Steve Dowrick, Y. D., 2001). It can be measured by means of economic indicators (GDP per capita, income distribution, the price level) and social (infrastructure, education, health, culture, employment and environment). For example, manufacturers produce various different products to satisfy the needs and wants of customers. Moreover, infrastructure construction facilitates economic productivity and enhances societal living conditions, which provide essential facilities and infrastructure, such as wind, solar, nuclear power stations that gratify the energy needs of the public. However, maintaining a high standard of living at the same time, it also causes inevitable destruction to the environment. This dilemma includes deterioration of the environment, destruction of ecosystems, air and ocean pollution along with global warming. Although the level of productivity is a significant factor for the improvement of living standards, as more service and materials are available to support a high quality of living, as a result, environmental problems are a serious...