restrictive blood flow to the muscles of the heart. The lack of blood deprives heart

muscles from enough oxygen and nutrients to carry out its work properly leading to

chest pain or angina.

When blockage becomes bigger in the coronary artery, there could be re-routing

of new blood vessels around the blockage which is known as collateral circulation.

Figure 16.3 shows collateral circulation developing around an area of reduced blood

flow. However, they may not be capable enough to carry sufficient blood to the heart

in a state of stress. When the heart muscles lack adequate supply of oxygen and

nutrients for its efficient working through its nano-arteries, the cramping of these

muscles may take place, and such a condition is termed as ischemia. Consequently,

the person may suffer pain in the chest in addition to other symptoms. Such a

condition may be experienced often when one is active, excited, stressed, or exposed

to cold. This condition may last for a brief time (~10 min) and may improve only

after taking rest. Such a condition may be termed as a stable angina. However, the

symptoms may persist even after taking a rest. For people with diabetes, the

symptoms may not surface, and such a cause could be termed as silent ischemia

(Gatimu et al. 2006; Nabel 2003; Louridas et al. 2010; Kemp and Conte 2012). In

Fig. 16.4, one can observe a situation where enough plaque builds up in artery and

makes it harder for blood to get through the artery leading to the state of angina in a

person. The lower portion of the figure displays a condition of heart attack where a

blood clot completely blocks the artery resulting from cracking of deposited plaque.

16.3

Role of Microfluidics and Nanofluidics

Surface properties of a system at micro- and nanoscales play an indomitable role as

its surface to volume ratio is quite large and the pressure drop is also quite signifi-

cant. Hence, it becomes quite imperative to transport biomaterial electrokinetically

Fig. 16.3 Collateral

circulation developing around

an area of reduced flow

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K. Tankeshwar and S. Srivastava