Cardiovascular: Human Plumbing - Arteries & Veins Flashcards
3 layers of an artery?
Differences between the artery layers depending on vessel size?
Branches vs tributaries?
Arteries have branches
Veins have tributaries
Describe the starling forces accross a capillary bed?
On arterial side osmotic pressure > oncotic pressure therefore fluid move out
On venous side osmotic pressure < oncotic pressure therefor fluid moves in
Describe what the following arterial pathologies mean?
- aneurysm
- stenosis
- occluded
- dissection
- vasospasm
- vasculitis
- broken
Definition of an aneurysm?
1.5x normal diameter
Most common form of aneurysm?
Other forms of aneurysm?
Degenerative aneurysms are the most common
- Inflammatory, mycotic (infective), traumatic can also occur
What does this CT angiogram show?
Aortic aneurysm
Describe the open surgery approach to aneurysm repair?
A large incision is made and a graft is placed to replace the area where the aneurysm was
Describe the endovascular approach to aneurysm repair?
A small incision is made and a catheter inserted into the artery. From here a graft is placed within the vessel rather than replacing it
Two options for repair of an aneurysm?
- Open surgery
- Endovascular repair
Most common cause of stenosis?
Atherosclerosis
What is atherosclerosis?
Thickening or hardening of the arteries caused by a buildup of plaque in the inner lining of an artery
Stenosis symptoms
Claudication:
- Pain on walking a fixed distance
- Worse uphill
- Eases rapidly when you stop
- Can think of as ANGINA of the leg
- As it gets can present as nocturnal pain / rest pain
Treatment of stenosis
- Stop smoking
- Movement
- Asperin to prevent thrombosis
- Statins to prevent plaque build up
What are the six Ps of acute occlussion?
- Pain (sudden onset)
- Palor
- Perishingly cold
- Parasthesia
- Pulselessness
- Paralysis
7 Symptoms of chronic occlusion?
- Short distance claudication
- Nocturnal pain
- Pain at rest
- Numbness
- Tissue necrosis
- Gangrene
- Things falling off
Treatment for tight stenosis or occlusion?
Can put in a stent however it doesn’t last long. Only do if it’s easy and can done under local aneasthetic.
If bad amputation only option. Prognosis is really bad 2.25years survival. This is because to get to point of amputation CVD is going to be bad all over body so survival already not good. And amputation will only make you more immobile and CVD worse.
Aterial dissection what is it and treatment
A split in the inner walls allows blood to get inbetween the layers causeing it to swell and sometimes occlude.
Sometimes it will heal itself. If not a stent is required
What is vasospasm?
WHat are its triggers?
This is overactive vasoconstriction particularly at the capillary level
Triggers are cold and stress
Cause of vasculitis depending on vessel size
- Large vessel – Takayasu’s disease – “the pulseless disease”
- Medium vessel – Giant Cell Arteritis / Polymyalgia Rheumatica
- Small vessel – lots of polyangiitis conditions usually involving the
kidneys
Just need to remember:
- Large - takayasu’s - pulseless
- Medium - rheumatica
- Small - kidneys
Treatment of vasculitis
Steroids and immunosupressants
Causes of brocken arteries
- Trauma
- Self inflicted
- Laterogenic - caused by a clinition making a mistake
How is an broken artery repaired?
When cut it will retract like a string under tension.
A tube is usually needed to divert blood flow while repair is odne.
What is an arterial psuedoaneurysm?
This is where an artery is punctured by mistake.
Either as an accident during intravenous drug use or laterogenically
Diabetic foot features
- Ischeamic
- Neuropathic
- Infected
End stage - charcot foot
Arterial vessel problems depending on size of vessel
Large vessels:
- Aneurysm
- Dissection
Medium vessels:
- Stenosis
- Occlusion
- Broken
Small vessels:
- Vasospasm
- Diabetic
All sizes:
- Vasculitis
- Pseudoaneurysm
Veins have many anastomoses. What does this mean for occlusion?
Occlusion isn’t so bad and it is easy for blood to redirect
There is no heart in the foot lol
How does blood return to the heart?
- Muscle pumps - each time you walk your muscles contract acting as a pump
- Thoracic pump action during respiration
- Gravity – lying down, elevating leg
- Right heart function
All of this requires functioning competent valves to stop blood flowing back when these conditions aren’t met
What is the symptom of venous hypertension?
Think about starling mechanism
Build up of fluid in the legs
Leads to itchy fragile skin which can ulcerate - particularly around the shins
Two ways venous return fails?
- Failure of muscle pump due to immobility of muscle wastage
- Failure of valves
What are varicose veins?
What is the difference between deep and superficial?
Failure of the valves int he veins
If superficial this isn’t really a problem as they don’t carry much blood. Can fix for cosmetic reasons
If deep can lead to venous hypertension
Treatment for venous hypertension
- Emoliant for cracked skin
- Graduated stockings - pressure decreases as you move up leg encouraging fluid upwards - different to TED stiockings
- Elevation
- Mobilisation
Treatments for varicose veins
Superficial veins:
- Endothermal ablation - burning form the inside
- Surgical removal
- Foam sclerotherapy
- Adhesive occlusion - block them with glue
- Compression
Deep veins:
- Compression
What can DVT lead to deep varacose veins?
What is thrombolysis?
Is a treament for DVT.
Afterwards you can hold veins open with a stent. But the problem is blood can now flow back leading to venous hypertension
Liver failure and venous hypertension?
Portal system drains from digestive system into liver.
With liver disease portal hypertension develops.
Portal system therefore divert into systemic drainage via anastomoses and these anastomoses can become varices.
What is lymphoedema?
Witht he starling mechanism you will notice that the pressure out of the arterial side is 10mmHg but the pressure in on the venous side is 9mmHg. This leads to some fluid being retained which is picked up by the lymphatic capillaries then intot he nodes then finally drained back via the thoracic duct.
If the lymphatic system is damaged this leads to build up of fluid - lymoedema.
Way the lymphatic system can get damaged leading to lymoedema?
- Congenitally
- Post surgically (lymphatic surgery for cancer)
- Post radio therepy
- From infection - filariasis
How can kidney damage lead to oedema?
- Colloid osmotic pressure (COP) is the osmotic pressure exerted into the vessles by large molecules (proteins)
- Renal failure can lead to low protein states causing a drop in osmotic pressure and hence oedema
How can inflammation lead to oedema?
Inflamation causes vasocodialation at arteriole level.
As there is now more fluid going in the drainage can’t keep up leading to odeama
How can right ventricular failure lead to peripheral oedema?
Central venous presure rises eventually leading to a rise in peripheral venous pressure leading to peripheral oedema
Summary of causes of oedema and varices
Venous hypertension:
- From valve failure - varicose veins, post DVT
- Immobility - not getting muscle pumped
- Liver failure - portal overload leads to systemic anasomoses overload - presents abdominal surface or in osephagus
- Right ventricular failure
Lymphatic - congenital, post cancer treatment or infection
Osmotic - kidney failure
