Biology Homework Information (1)

7/25/2019 Biology Homework Information (1)

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Stents- What are they?

A stent is a narrow mesh that is used to treat narrow and weak bloodarteries (typically the coronary arteries supplying blood to the heart

muscle). They are also used to treat arteries that have restricted

blood flow, because of a build-up of plaque. Arteries are the blood

vessels that carry blood away from your heart. tents work by either

widening the artery and!or compressing the plaque inside it, up

against the artery wall. They also help to improve blood flow. A

typical stent is usually made out of metal, but can also be made out

of fabric. The fabric stent is used in wider arteries.

tents are inserted into arteries as part of a procedure called

"ercutaneous #oronary $ntervention ("#$), sometimes called an

angioplasty. A doctor makes a small opening in your arm, neck or

upper thigh and feeds a small fle%ible tube through into the artery,

called a catheter, which is attached to a small balloon that has a

compressed stent around it. The balloon is then inflated. As the

balloon is inflated, it pushes the plaque to the side of the artery and

helps to increase blood flow. The balloon also inflates and e%pands

the stent, which reduce the chance of the artery narrowing, andincreases blood flow. &ver time, cells will grow in your artery to

cover the mesh of the stent. They create an inner layer that looks

like the inside of a normal blood vessel. ome stents are also coated

in medicine that is released continuously into the artery, to prevent

scar tissue from blocking the artery again.



Artificial Heart Valves- Biological and

Mechanical&ccasionally, some people's heart valves become stiff or leaky, or

maybe even diseased, which prevents the valves from functioning

properly to prevent the backflow of blood. $n these circumstances, it

is possible to replace the faulty valves with either valves from a

biological source (for e%ample from a human or animal donor) or by

using mechanical (man-made) valves. "atients that have diseased

valves are said to have valvular heart disease (*).

Biological Heart Valves

+iological eart valves are created from animal

donors' valves or other animal tissue that

is strong and fle%ible. Tissue valves can last -

years, and usually don/t require the long-term use of

medication. 0or a young person with a tissue

valve replacement, the need for additional

surgery or another valve replacement later in

life is highly likely.

Mechanical Heart Valves

These valves are made of strong durable

materials and are the most long-lasting type of

replacement valve, and most of these mechanical

valves will last throughout the remainder of the

patients' lifetime. "atients who receive a

mechanical valve will nearly alwaysrequire a blood thinning medication

throughout the remainder of their lives. This medicine will keep

clots from forming, which is critical for the person with the valve

because clots can lodge in the valve flaps or hinges and cause a

malfunction. #lots can also break off and form into an embolism (a

travelling clot), which may move through the

Advantages and Disadvantages bloodstream and lodge into a blood vessel where it may eventually

lead to other problems such as a heart attack or stroke.



Stents Advantages Disadvantages

. elps to widen the artery.

. 1o ma2or surgery needed.

3. 4a2or complications are

uncommon.

5. 4ost patients don/t require

general anasthesia.

6. &ne day recoveries.

7. "atients can return to their

normal activities quickly.

8. 9ow risk rate.

. :enarrowing of the artery is

still possible, called restenosis.

. ery rarely, stent thrombosis

may occur, which is a blood clot

caused by a a stent.

3. The catheter insertion site will

become bruised and may be

prone to infection.

5. :estenosis occurs within 6

to 3; of patients.

Biological Heart Valves Advantages Disadvantages

. 6; of patients do not need

blood anticoagulant.

. <uiet- no annoying noise to

patients

3. ome are efficient in small

si=es.

5. +lood thinner only need blood

thinner for about 3 months.

. alve has to be changed every

few years.

. alve may need to be

reoperated on if there are any

problems.

3. 4ay be prone to infection and

damage from blood clots.

5. $ngrown scars- pannus growth

Mechanical Heart Valves Advantages Disadvantages

. >sually only one operation

needed.

. 9asts for a lifetime.

3. +etter survival rates.

5. +etter efficiency in small

si=es.

. "atients must take blood

thinner (anticoagulant).

. ome patients are annoyed by

the clicking noise they make.

3.There is a possibility of stroke.

5. "ossible ingrown scars.



Research Sources

1- Pros and ons of Valves

http?!!www.on%lti.com!patie

nt-guide!pros-cons-option-

heart-valve-replacement!

!-Benefits and Ris"s of Valveshttp?!!www.medtronic.com!patients!coron

ary-artery-disease!therapy!balloon-

angioplasty-and-stenting!benefits-risks!

$ think that resource was better as it was more descriptive and

informative. $t contained a table and a detailed summary,

accompanied by 5 bulleted lists for ease of reading.

:esource was useful, but it didn/t have an equal balance of

information, as on biological valves it had only 3 points, whereas

the mechanical valves had about to 6 points. owever, it did

have a better layout and was easier to understand and navigate.

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Biology Homework Information (1)