Flow and Stopping Flashcards
What is the embolic process?
Not all emboli are blood clots (a blood clot embolism is called a thromboembolism) – different types can include a piece of cholesterol or more rarely, gas/air bubbles
Consider the direction of circulation in the body and think how a clot in the leg (DVT) can cause a pulmonary embolism. What is the connection between leg and lung?
Blood vessels decrease in size along the pathway of blood circulation until they become tiny capillaries.
* If a clot of any type becomes detached and mobile in the circulation it travels along vessels until it reaches one too small for it to pass through…
* Blockage results in oxygen not reaching the tissue, so tissue ischaemia (oxygen starvation) as blood supply cannot reach tissues distal to the embolus
What is the link between Arrhythmia and Clots?
Think back to atrial fibrillation in our previous lesson – the key complication is thromboembolic disease, especially stroke. How does this condition increase clot risk?
The **heart needs to beat in a rhythmic fashion to allow smooth flow of blood through its vessels and chambers. Atrial fibrillation causes uncoordinated rhythm **and so a turbulent and interrupted passage of blood around the heart – blood remains in the left atria more often allowing clot formation to take place
How does this then cause stroke?
Clots from the left atrium travel through the left ventricle, into the aorta and through
the carotid artery (going up), passing through vessels of decreasing size until becoming lodged. Blockage leads to ischaemia of a section of brain tissue - stroke.
What is deep vein thrombosis?
Probably the most well known pathology arising from problem clotting is deep vein
thrombosis (DVT). Key risk factors for DVT:
* Prolonged periods of no movement
* Pregnancy
* Surgery or injury
* Being overweight or obese
These have in common that blood is flowing less rapidly and there is greater pressure on vessels, so clotting in the vein is more probable.
What is a key complication of DVT?
Pulmonary embolism, where part or whole clot breaks free and travels around
the circulation to lodge in a small vessel in the lungs.
Think of the path of blood flow around the veins of the body and imagine the
journey of the clot from leg to lung – how does it get there? (Up from legs into the heart via the systemic system then into the pulmonary system)
What is the link between atherosclerotic plaques and heart attacks?
We have looked at how atherosclerosis develops and impacts the heart – now we can consider how this relates to clots and
their impacts.
* Atherosclerosis narrows vessels through the development of atherosclerotic plaques
* If a plaque is put under sufficient pressure it will rupture
* This spills cholesterol and other plaque contents into the vessel
* Formation of a clot is triggered
* If this has occurred in a coronary artery, blood flow to an area of the heart is blocked, or occluded
* Ischaemia of the heart muscle causes heart attack
What are the risk factors for clots?
- Hypertension - can be mitigated
- Atherosclerosis - can try and stop it being developed, and manage to a degree
- Atrial fibrillation - can be managed and mitigated
- Bleeding and clotting disorders - less easy, needs orthodox medicine, but can support
- Inflammation - can be mitigated
- Insulin resistance
