Week 3/4 - C - Peripheral arterial disease - Intermittent claudication, Critical limb ischaemia, acute limb ischaemia, Abdominal aortic aneurysm, Aortic dissection Flashcards
Coronary heart disease is a common cause of health and disability Primary prevention is the kye Secondary treatment occurs after an atherosclerotic cardiovascular disease (ASCVD) event takes place What does the stable accumulation of flow restriction cause? What are the unstable clinical syndromes cause by this?
Angina is due to the stable accumulation of flow restriction The unstable syndromes are known as acute coronary syndrome * Unstable angin * STEMI * NSTEMI
What can the inadequate systemic perfusion of the heart lead to resulting in cardiac dysfunction?
This can cause cardiogenic shock Cardiogenic shock is a condition in which your heart suddenly can’t pump enough blood to meet your body’s needs. The condition is most often caused by a severe heart attack
What is the lifestyle advice given for preventing of cardiovascular disease?
STOP SMOKING Dietary advice Regular exercise
Describe atherosclerosis pathogenesis?
* Endothelial injury - eg smoking, HBP, cholesterol * Platelet and monocyte aggregation at site of injury * LDL become oxidised and are engulfed by macrophages (monocytes have become macrophages) - forms a foam cell/fatty streak * Platelets/foam cells release inflamamtory substances causing smooth muscle proliferation and migration * Fibrous cap formed by smooth muscle and collagen/elastin * Fibrofatty streak = atheroma (plaque)
What is intermittent claudication?
Intermittent claudication, also known as vascular claudication, is a symptom that describes muscle pain on mild exertion (ache, cramp, numbness or sense of fatigue), classically in the calf muscle, which occurs during exercise, such as walking, and is relieved by a short period of rest.
What are the symptoms of intermittent claudication?
Symptoms - patient is pain free at rest Cramping pain in calf, thigh or buttocks appears after walking for a given distance and is relieved by rest CLAUDICATION - muscle ischaemia on EXERCISE
What are the signs of intermittent claudication?
Signs inclde - absent femoral, popliteal or foot pulses White leg(s) Atrophic skin or punched out ulcers Sometimes hair loss on legs/feet
How is peripheral vascular disease diagnosed?
Preipheral arterial disease usually is diagnosed with non-invasive investigations * Measurment of ABPI using Doppler ultrasound scanning
How is Ankle brachial pressure index measured?
Ankle brachial pressure index = Ankle / brachial pressure * The sound of arterial blood flow is located using a doppler ultrasound probe * The higher systolic reading of the left and right arm brachial artery is generally used * The pressures in each foot’s posterior tibial artery and dorsalis pedis artery are measured with the higher of the two values used as the ankle pressure for that leg
What score signifies * Peripheral arterial disease? * Critical limb ischaemia?
- * Normal = 0.9-1.2
- * Peripheral arterial disease = 0.5-0.9
- * Critical limb ischaemia =<0.5
When may the ABPI give false positives? What disease may cause this?
ABPI may give false positives if there is severe atherosclerosis of the ankle arteries causing incompressible calcified arteries Seen in eg diabetes mellitus
What type of non-invasive imaging is sometimes carried out to diagnose PAD?
This would be colour duplex ultrasound scanning - combines the US of a doppler scan and converts the sound waves into 3D images - assesses degree and location of stenosis
What invasive investigations can be carried out in peripheral arterial disease? Usually reserved for when considering intervention
This would be MR/CT angiography - allows the extent and location of stensois as well as quality of distant vessels to be assessed
What is the treatment of intermittent claudication? * Risk factor modification * Non pharmacooigcla management * Pharmacoloigcla management
Risk factor modification - QUIT SMOKING, treat hypertension and high cholesterol (and diabetes if exists) Non pharmacological - Supervised exercise programme offered - 2hrs / week for 3 months of walking until maximum pain - to improve collateral blood flow Pharmacological management - prescribe anti-platelet - clopidogrel is first line
If supervised exercise fails to improve symptoms and patients do not wish to undergo revascularisation for the intermittent claudication, what drug can be offered?
Naftidrofuryl oxalate is an option for the treatment of intermittent claudication in patients with peripheral arterial disease in whom do not wish to undergo revascularisation and supervised exercise programmes ahve failed - it causes vasodilation It is a 5-HT2 receptor antagonist
Patients with lifestyle-limiting claudication who have had no improvement with exercise and symptom relief should be referred to a vascular specialist to have their arterial anatomy defined and assessed What are the surgical intervention options?
Angioplasty (percutaneous transluminal angioplasty - PTA) Surgical reconstruction using a bypass graft Amputation - last line and patients decision
When is angioplasty indicated for intermittent claudication?
Angioplasty carried out for disease limited to a single arterial segment causing stenosis - a balloon is inflated in the narrow segment Stents can be inserted to maintain patency
When is a bypass graft indicated for intermittent claudication? What are the different graft procedures? (ie from which artery to which artery)
Bypass graft - if atheromatous disease is severe but distal run-off is good (distal arteries) Autologous graft - eg saphenous vein Prosthetic graft - eg dacron (man made) Eg Femoral-popliteal bypass Femoral-femoral crossover Aorto-bifemoral bypass
Why is the pain at night in the feet worse and why do the patients hang the feet off the bed in critical limb ischaemia?
Chronic rest pain, which may be worse at night because of the decrease in blood pressure when asleep and the loss of beneficial gravitational effects on lower limb circulation. People may report sleeping with the leg hanging out of bed, or sleep in a chair to relieve symptoms in the affected foot.
What is the ABPI in critical limb ischaemia? We know the cardinal feature include ulceration, gangrene and foot pain at rest What are other symptoms of CLI? (similar to features of IC)
ABPI <0.5 Other features include Cold to touch Absence of peripheral pulses Poor tissue nutrition
What is the management of critical limb ischaemia?
Lifestyle modification - STOP SMOKING, exercise Pain management for the patient should be provided - eg opioids Patient should be assessed for revascularisation eg bypass or angioplasty (aka endovascular treatment) Patient may require amputation
What is the definition of an aneursym? What size must it be to be a true arterial aneurysm?
An aneursym occurs due to a weakness in the arterial wall causing a pooling of blood A true arterial aneurysm is an artery with a 50% increase in its oriignal diameter
What are the surgical management options for an abdominal aortic aneurysm?
Which is offered for patients meeting the criteria in an unruptured AAA?
Two treatment options for AAA - open surgical repair and endovascular aneurysm repair (EVAR)
If unruptured - Offer open surgical repair. DO NOT OFFER EVAR even if open surgical repair unsuitable
As stated previously, any patient with a suspected AAA rupture should receive an USS, and if positive or indefinite diagnosis, consider CT angiography
What is the preferred surgical option for ruptured AAA?
Consider EVAR (endovascular aneurysm repair)
- * if female
- * in male >70
Consider open surgery
- * All complex AAA
- * Infrarenal AAA in men
What is a complex AAA?
Complex AAA are aneurysms that occur above the kidneys (suprarenal) - offer open surgical repair in all cases if these rupture
Aortic dissection is a rare but serious cause of chest pain
What is the pathophysiology of aortic dissection?
What is the false lumen?
A spontaneous tear of the aortic tunica intima occurs allowing high pressure blood to enter the tunica media
This high pressure flow of blood causes a longitudinal split to develop within the media through which blood circulates - this is the false lumen
The false lumen may re-enter the lumen distally
What tests would be carried out to aid in the diagnosis of an aortic dissection?
- the majority of patients have no or non-specific ECG changes. In a minority of patients, ST-segment elevation may be seen in the inferior leads
- Troponins - can be elevated
- CXR - can show a widened mediastinum, aneurysmal dilatation of the descending aorta due to the creation of a false lumen
What is the investigation of choice for people with a suspected aortic dissection?
CT angiography of the chest, abdomen and pelvis is the investigation of choice
- suitable for stable patients and for planning surgery
- a false lumen is a key finding in diagnosing aortic dissection
(transoesophageal echo (TOE) may be used for for unstable patients who are too risky to take to CT scanner)
There are different classification systems for aortic dissection
Two commonly used are Standford and DeBakey classification - we will discuss the standford classifciation
Discuss the Standford Classification? Is type A or B more common?
Stanford classification
- type A - ascending aorta, 2/3 of cases
- type B - descending aorta, distal to left subclavian origin, 1/3 of cases
