Peripheral Vascular Disease Flashcards
- what is the peripheral vascular system?
- What are the structures?
- all blood vessels outside of the heart
- Aorta and its arterial branches (arterioles and capillaries)
Vena Cava and its vein branches (venules and capillaries)
what are the components of all blood vessels (4)?
- Tunica externa (adventitia) (outer layer) provides structural support and shape to the vessel
- tunica media (middle layer) elastic and muscular middle layer that regulates the internal diameter of the vessel
- tunica intima (innermost layer) the endothelial lining that provides a frictionless pathway for the movement of blood
- Lumen is the hallow passageway where the blood flows
- what type of blood do the arteries carry?
- What is the composition of the arteries? what influences them?
- oxygenated blood to organs and muscles
- arteries are elastic and muscular and influenced by the ANS
- what are the muscular arteries?
- what are the elastic arteries?
- brachial, femoral, radial
- those closest to the heart
what percentage of total blood supply is in the arterial system?
10-15%
- what is the job of the arterioles?
- What input do they respond to?
- What do they play a role in?
- The arterioles supply blood to the organs
- They are primarily smooth muscles that respond to ANS input
- Due to lack of elastin, they play a role in peripheral resistance (HTN)
What is the job of the capillaries?
thin, single endothelial layer that allows for the exchange of oxygen and nutrients
- What are the venuoles and where do they receive blood from?
- what is the job of the venuoles?
- what can they NOT withstand?
- the venuoles are small and receive blood from venous capillaries after sphincter
- participate in the nutrient exchange process
- can not withstand high pressure and can rupture
- where do the veins receive blood from?
- What is the composition of veins and what is their job?
- what % of total blood is in the venous system?
- Describe the valves of the veins and blood flow
- receive blood from the venuoles
- The veins have similar anatomy to arteries but they accommodate much LESS pressure. Veins are thin walled and elastic. They have high capacitance meaning they accommodate large blood vol at low pressures.
- 75% of blood is in the venous system
- veins have one-way valves that maintain forward blood slow toward the heart against gravity
Compare and contrast arteries and veins
- Arteries have thicker walls, more smooth muscle, and a small lumen. Arteries maintain pressure throughout the system and appear rounder.
- Veins have thinner walls, less smooth muscle, and a larger lumen. Veins return blood to the heart and lungs and appear more collapsible.
What is peripheral vascular disease?
An umbrella term that encompasses diseases of the arterial, venous, and lymphatic systems.
Includes diseases of the aorta, PAD, venous diseases, Vasospasms
What are the most common clinical conditions of the aorta?
Aneurysm, dissection, obstruction
- What type of trauma is the aorta commonly subjected to?
- What happens to the composition of the aorta as we age?
- The aorta is subject to mechanical trauma due to continuous exposure to high pulsatile pressure
- The aorta has high elastin content in the tunica media which allows for significant distensibility (ability to stretch and expand).
Systole= Expansion
Diastole= recoil
As we age, elastin degenerates and the aorta becomes stiffer which increases systolic BP
- what is a pseudoaneurysm?
- what is the common cause?
- A contained rupture of the vessel lumen that develops when blood leaks out of a hole in the intima and media layers and is contained by the adventitia. Very unstable and prone to rupture.
- caused by infection, trauma, puncture such as cardiac cath
- What percentage of dilation is classified as an aneurysm?
- What is considered a true aneurysm?
- when increased by 50% compared with normal
- dilation of all 3 layers of the aorta, creating a large bulge in the vessel wall
what are the most common aneurysms?
abdominal is the most common followed by thoracic
what are the causes/ conditions associated with aortic aneurysms?
- medical degeneration: marfans, elher-danlos, loeys- dietz, aortic valve problems, genetics
- atherosclerosis
- infections
- vasculitis
- trauma or aortic dissection
what are the main causes of descending aortic and abdominal aneurysms? (4)
- atherosclerosis; commonly seen in older male with hx of smoking, HTN, dyslipedemia, and caucasian
- genetic predisposition
- vessel inflammation
- weakened tunica media due to infection from salmonella, staphylococci, streptococci, TB, or syphillis
what is the clinical presentation of aortic/ abdominal aneurysms? (4)
- Most patients are asymptomatic but can sometimes feel a pulsatile mass or sensation in the abdomen
- feeling of another organ (kidney or intestine) being constricted or pressed
- non-specific back pain, nausea, abdominal pain, pain in the flanks that radiates to the legs
- general malaise if due to infection, weight loss if due to inflammation
What is the presentation of a thoracic aneurysm?
Often asymptomatic but when they are symptomatic there is compression of neighboring structures such as the trachea, main bronchus, and esophagus.
Can present with cough, dysphagia, and hoarseness due to the recurrent laryngeal nerve
what is the clinical presentation of an aneurysm of the ascending aorta?
aortic regurgitation and symptoms of CHF
- What is the common presentation of slow leaks (aneurysms)?
- What is the common presentation of a rupture?
- diffuse, deep belly pain, GI symptoms, bloating, cramping
- hypovolemia, hypotension, deep pain in the back or abdomen, vomiting, diaphoresis, loss of consciousness
what are risk factors for rupture?
Increasing size
Rapid expansion
Tobacco use
Increased or uncontrolled HTN
Cardiac or renal transplant COPD (increased intrathoracic pressure)
Female (decreased tensile strength and increased wall stress)
Recent surgery (stress on the body)
What is required for diagnosis of a aortic aneurysm?
imaging, screening (men 65-75 who have hx of smoking), abdominal palpation (mainly reliable with large AAA)
- what is the treatment for a unruptured aneurysm?
- what is the treatment for a rupture aneurysm?
- manage underlying disease process and risk factors, repair surgically or endovascularly
- emergent surgery, survival rate is <50%
What is an aortic dissection? Where is it most common?
A tear in the intima and media that spreads along the artery causing blood to flow in between the layers of the blood vessel which can lead to an aortic rupture. Most commonly happens in the thoracic aorta. It is life threatening.
what are risk factors for aortic dissection?
atherosclerosis, blunt trauma to the chest, and HTN
What is the common presentation of an aortic dissection?
- Sudden onset of chest or back pain with a tearing or ripping sensation that can radiate to the shoulder, jaw, arm, and neck.
- Signs of hypoperfusion like dizziness or syncope
- nausea and vomiting
- rapid and weak pulse
what is the most common cause of PAD?
atherosclerosis
what are risk factors for PAD?
- CAD/ atherosclerosis
- advanced age
- hypercholesterolemia
- smoking
- HTN
- diabetes
- overweight
- family HX
What patients are at an increased risk of PAD? (table 3)
- age >65
- age 50-64 with risk factors for atherosclerosis such as DM, hx smoking, hyperlipidemia, HTN, family hx
- age <50 with DM and 1 risk factor for atherosclerosis
- people with known atherosclerosis in another vascular bed (coronary, carotid, subclavian, renal, mesenteric stenosis, AAA)
- AAA
what hx findings are suggestive of PAD? (table 4)
- claudication
- non joint related exertional LE symptoms
- impaired walking function
- ischemic resting pain
what findings on physical examination are suggestive of PAD? (table 4)
- abnormal LE pulse examination
- vascular bruit
- nonhealing LE wound
- LE gangrene
- elevated pallor and dependent rubor
- What is the pathophysiology of PAD? 2. What happens to the blood vessels?
- Similar to CAD, there is a mismatch of the demands of the organs and muscles and the supply of O2 due to a atherosclerotic stenosis of the peripheral arteries.
- There is reduced diameter of the blood vessels which leads to ischemia
Describe pathophysiology of PAD and exercising muscle
- During exercise skeletal muscles metabolism produces adenosine which acts to dilate arterioles to increase blood flow to the muscles. Obstructed arteries cant respond to the vasodilating stimuli which means blood flow becomes limited leading to ischemia.