Beth talks blood: Part 8

What is cardiovascular disease?
Cardiovascular disease (CVD) is a general term for conditions affecting the heart or blood vessels. It is typically associated with a build of fatty deposits inside blood vessels known as atherosclerosis and an increased risk of blood clots known as thrombosis [1-2]. It can also be associated with damage to arteries in organs such as the brain, heart, kidneys and eyes. 

Unfortunately, CVD is one of the main causes of death and disability in the UK and sadly the number one cause of death globally, more people die annually from CVDs than from any other cause! However, for the most part, CVD can be prevented by following a healthy lifestyle [1-3].

Types of CVD:

Coronary heart disease:
Coronary heart disease occurs when flow blood supplying the heart muscle is blocked or reduced.

Coronary heart disease can put added strain on the heart which can lead to:

  1. Angina – chest pain caused by restricted blood flow to the heart muscle
  2. Heart attack – blood flow to the heart is suddenly blocked
  3. Heart failure – the heart is unable to pump blood around the body properly

CHD develops slowly over time and the symptoms are different for everyone. Some people don’t know they have CHD until they have a cardiovascular event such as a heart attack! [1, 3-4]

Cerebrovascular disease (CeVD) :
A disease of the blood vessels supplying the brain [2]. Ischaemic stroke occurs when blood flow is restricted or cut off in part of the brain which can lead to brain damage and possible death [1-4]. Strokes can also be caused by bleeding from a blood vessel in the brain or from blood clots, this is known as a haemorrhagic stroke. Transient ischaemic attacks (TIAs) or mini-strokes happen when there is an interruption of blood flow to part of the brain for a very short time. TIAs can cause symptoms such as temporary speech loss and they can typically resolve after a few seconds or minutes [1-5].

Peripheral arterial disease (PAD): 
A disease of blood vessels supplying the arms and legs and occurs when there’s a blockage in the arteries to the limbs. This can lead to dull or cramping leg pain when walking which gets better with rest, hair loss on legs and feet, numbness or weakness in the legs and persistent ulcers on the feet and legs [1-3]. PAD is also likely to be a sign of more widespread accumulation of atherosclerosis, which may be reducing blood flow elsewhere i.e. heart or brain. PAD can be managed by quitting smoking and following a healthy diet [6].

Rheumatic heart disease:
A disease which causes damage to the heart muscle and heart valves from rheumatic fever, which caused by streptococcal bacteria [3]. Rheumatic fever is an inflammatory disease that can affect many connective tissues, especially in the heart, joints, skin or brain. During rheumatic fever, the heart valves become inflamed and can scar over time. This results in the narrowing or leaking of the heart valves meaning it is harder for the heart to function normally. It can take years to develop but may result in heart failure [3, 7]. 

Congenital heart disease (CHD): 
A general term for a range of birth defects that affect the normal functioning of the heart. CHD can be due to malformations in the heart structure existing at birth. CHD is one of the most common birth defects, it affects up to 8 in every 1000 babies born in the UK [3, 8].

Types of CHD:

  1. Septal defects – a hole between two of the hearts chambers (referred to as “hole in the heart”)
  2. Coarctation of the aortanarrower aorta than normal
  3. Pulmonary valve stenosispulmonary valve which controls the flow of blood out of the heart to the lungs is lower than normal 
  4. Transposition of the great arteries – the pulmonary and aortic valve and the arteries they’re connected to have swapped positions
  5. Underdeveloped heart – the heart doesn’t develop properly which can make it difficult for it to pump enough blood around the body

It can happen as a result of many things such as Down’s syndrome, issues during pregnancy such as diabetes, medications and family history.

Deep vein thrombosis (DVT) and pulmonary embolism (PE):
Blood clots in the leg veins, which can dislodge and move to the heart and lungs [1-3]. DVT can cause leg pain or swelling but it can also occur without symptoms [9]. DVT can be dangerous if left untreated it can lead to pulmonary embolism (PE). This is where blood blots break loose and travel through the bloodstream and lodge in the lungs blocking blood flow [10].

Aortic disease:
A group of diseases affecting the aorta which is the largest blood vessel in the body. It carries blood from the heart to the rest of the body. The most common aortic disease is an aortic aneurysm whereby the aorta becomes weakened and bulges [1]. Aortic aneurysm doesn’t have any symptoms and it is very dangerous if not spotted early. There is a chance it could rupture (burst) which can lead to life-threatening bleeding [11]. 

Atherosclerosis 
Atherosclerosis is a very slow process that happens over many years, it can start early in life and results in a build-up of fatty deposits (atheroma) in the lining of blood vessels. If you remember from my previous blog post about fatty acids in the blood, LDL is “bad” cholesterol whereas HDL is “good” cholesterol. These fatty deposits start when the blood vessel lining becomes damaged, which makes it easier for the cholesterol (on LDL) to stick on and build up more rapidly leading to the formation of plaques [12]. HDL however, can remove these fatty deposits. Reducing LDL and increasing HDL as well as reducing other risk factors (such as blood pressure, type 2 diabetes, weight and smoking) can slow down the process of atherosclerosis.

During atherosclerosis plaques can rupture, when this occurs the ruptured plaque can recruit platelets to the rupture site, in a very similar fashion to vascular injury. This causes the platelets to activate and along with clotting factors, form an unwanted blood clot. The problem with a blood clot formed without vascular injury is that it can cause blockage of the affected blood vessel. A result of this blockage in combination with reduced blood flow can cause life-threatening cardiovascular events such as heart attack or stroke [13]. In some cases, the blockage can cause a portion of the heart to die which again can lead to a heart attack.

Fatty acids, atherosclerosis, platelets & CVD – how does it all link? 
Excess fatty acids in the blood can exert a profound effect on blood clotting and can lead to hypercoagulability of the blood, which in turn can lead to thrombosis [14]. LDL attaches to a protein on the surface of platelets called CD36 which causes platelets to become “stickier”. When this happens, platelets release chemicals that cause inflammation and can damage the walls of the blood vessels, contributing to the creation of these atherosclerotic plaques [15].

Risk factors of CVD [1]:

  • high blood pressure
  • smoking
  • high cholesterol 
  • diabetes
  • inactivity 
  • obesity 
  • family history 
  • ethnic background 
  • age
  • gender
  • diet
  • alcohol 

CVDs are likely to be a multifactorial process, which includes interactions between LDLs, platelets, clotting factors, blood vessel walls and inflammation, that together contribute to the development of CVD. In most cases, CVD can be prevented by reducing risk factors and leading a healthy lifestyle. For heart-healthy recipes check out some of the tasty recipes in the BHF’s Heart Matters magazine.

A healthy heart is a happy heart, looking after our cardiovascular health can really help reduce the NHS burden and hopefully one day, CVD won’t be the leading cause of death worldwide! 

As a cardiovascular research scientist, I firmly believe that developing our understanding of the cardiovascular system and what goes wrong at a cellular level during cardiovascular disease will help us to provide improved preventative measures and/or more targeted treatments. 

Thank you for reading, I hope you enjoyed this post!

See you in the next one.

Beth x

References:

[1] nhs.uk. 2020. Cardiovascular Disease. [online] Available at: <https://www.nhs.uk/conditions/cardiovascular-disease/&gt;

[2] http://www.heart.org. 2020. What Is Cardiovascular Disease?. [online] Available at: <https://www.heart.org/en/health-topics/consumer-healthcare/what-is-cardiovascular-disease&gt;

[3] Who.int. 2020. Cardiovascular Diseases (Cvds). [online] Available at: <https://www.who.int/news-room/fact-sheets/detail/cardiovascular-diseases-(cvds)&gt;

[4] British Heart Foundation. 2020. Coronary Heart Disease. [online] Available at: <https://www.bhf.org.uk/informationsupport/conditions/coronary-heart-disease&gt;

[5] British Heart Foundation. 2020. Stroke – Causes, Signs And Symptoms. [online] Available at: <https://www.bhf.org.uk/informationsupport/conditions/stroke&gt;

[6] Mayo Clinic. 2020. Peripheral Artery Disease (PAD) – Symptoms And Causes. [online] Available at: <https://www.mayoclinic.org/diseases-conditions/peripheral-artery-disease/symptoms-causes/syc-20350557&gt;

[7] 2020. Rheumatic Heart Disease. [online] Available at: <https://www.hopkinsmedicine.org/health/conditions-and-diseases/rheumatic-heart-disease&gt;

[8] Bhf.org.uk. 2020. Congenital Heart Disease. [online] Available at: <https://www.bhf.org.uk/informationsupport/conditions/congenital-heart-disease&gt;

[9] Mayo Clinic. 2020. Deep Vein Thrombosis – Symptoms And Causes. [online] Available at: <https://www.mayoclinic.org/diseases-conditions/deep-vein-thrombosis/symptoms-causes/syc-20352557>

[10] Mayo Clinic. 2020. Pulmonary Embolism – Symptoms And Causes. [online] Available at: <https://www.mayoclinic.org/diseases-conditions/pulmonary-embolism/symptoms-causes/syc-20354647&gt;

[11] nhs.uk. 2020. Abdominal Aortic Aneurysm. [online] Available at: <https://www.nhs.uk/conditions/abdominal-aortic-aneurysm/&gt;

[12] Siri-Tarino, P., Sun, Q., Hu, F. and Krauss, R., 2010. Saturated Fatty Acids and RisCoronary Heart Disease: Modulation by Replacement Nutrients. Current Atherosclerosis Reports, 12(6), pp.384-390. http://www.heart.org. 2020. Atherosclerosis. [online] Available at: <https://www.heart.org/en/health-topics/cholesterol/about-cholesterol/atherosclerosis&gt;

[13] http://www.heart.org. 2020. Atherosclerosis. [online] Available at: <https://www.heart.org/en/health-topics/cholesterol/about-cholesterol/atherosclerosis&gt;

[14] HOOK, J., WARNER, E. and CONNOR, W., 1967. Platelets, Fatty Acids and Thrombosis. Circulation Research, 20(1), pp.11-17. <https://www.ahajournals.org/doi/pdf/10.1161/01.RES.20.1.11>

[15] Bhf.org.uk. 2020. How Do Cholesterol And Platelets Team Up To Cause Blood Vessel Damage?. [online] Available at: <https://www.bhf.org.uk/research-projects/characterising-the-thromboinflammatory-roles-of-platelet-cd36&gt;

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: