Peripheral Vascular Disease Flashcards
What is peripheral vascular disease?
PVD is a chronic condition that is a result of atherosclerotic disease in the arteries of the limbs
How does extent of atherosclerosis affect symptoms in PVD?
the level of arterial occlusion present is proportional to the severity of the symptoms
What are the risk factors for peripheral vascular disease?
the risk factors are the same as for coronary artery disease (CAD)
- hypertension
- dyslipidaemia
- high LDL and low HDL
- diabetes
- obesity
- advancing age
- male gender
- family history of arterial disease
- significant if a first degree relative had MI before age 55
- smoking
How does peripheral vascular disease typically present?
pain in the lower limbs that is brought by exertion and relieved with rest
typically the patient will be able to walk a specific distance before the pain comes on
it can present as an emergency as acute limb ischaemia
What % of the population are affected by PVD?
it affects 10-15% of the population
What condition is nearly always present in patients with PVD?
75% of patients with PVD also have symptomatic coronary artery disease (CAD)
in the other 25% of patients it is thought that the PVD masks their CAD as they do not exert themselves sufficiently to bring on the CAD symptoms
What is the name of the type of pain present in PVD?
intermittent claudication
this decribes pain/cramping in the lower leg due to inadequate blood flow to the muscles
this often makes the patient limp
What is the classical presentation of PVD?
pain = intermittent claudication
- pain in the calves on walking that is relieved with rest
- pain can occur anywhere along the leg and down into the foot
- pain may occur when legs are raised (in bed) and is alleviated when legs are lowered (sitting)
Why do some patients with PVD not present with the classical picture of intermittent claudication?
often because they are not doing enough physical activity to induce the symptoms
particularly if they have another comorbidity that limits their activity
What is the main differential for peripheral vascular disease?
spinal claudication
caused by impingement of the cauda equina by a spinal stenosis
this classically causes pain in the back of the legs on exertion
What clinical test is performed that is specific to PVD?
Buerger’s test
this is an assessment of arterial sufficiency
the vascular angle (Buerger’s angle) is the angle the leg has to be raised before it becomes cold/pale, whilst lying down
How is Buerger’s angle different in a healthy person and someone with PVD?
healthy person:
- the toes and sole of the foot remain pink even when the limb is raised to 90 degrees
PVD:
- elevation to 15-30 degrees for 30-60 seconds may cause pallor
- Buerger’s angle of <20 degrees** indicates **severe PVD/ischaemia
How is capillary refill time changed in a patient with PVD?
- press the distal phalanx of patient’s toe with a finger for 5 seconds
- blanching discolouration should return to normal in less than 2 seconds
- capillary refill time is PROLONGED (>2 seconds) in someone with PVD due to poor peripheral perfusion
What skin changes may be present on the lower limb of someone with PVD?
there may be evidence of poor skin health due to poor perfusion, such as:
- ulcers
- dry, scaly skin
- cool peripheries
- prolonged capillary refill time
oedema should not be present
What pulses are assessed in PVD?
What does the presence or absence of a pulse suggest?
the pulses in the foot - posterior tibial & dorsalis pedis
- palpable pulse indicates low likelihood of PVD
- absent pulse indicates high likelihood of PVD
a doppler probe can be used to assess if there is significant blood flow present in the artery if pulses cannot be palpated
What is the main symptom of mild PVD?
claudication
this is limb pain (aching, cramping & tired feeling of the legs) upon exertion
most commonly occurs in the calves, but may also present in the feet, thighs, buttocks and arms
What is meant by the claudication distance?
How does this change as PVD progresses?
the distance that a patient can walk before they experience symptoms (pain)
as PVD progresses, the distance a patient can walk (claudication distance) is reduced
How is claudication / pain different for a patient who has severe PVD opposed to mild PVD?
- there is claudication / buttock pain at rest
- burning pain in the legs at night due to elevation (which reduces limb perfusion)
- burning pain relieved by hanging the legs over the side of the bed (v poor prognostic sign)
What other signs / symptoms should be looked out for in a patient suspected to have peripheral vascular disease?
- “punched out” ischaemic ulcers
- gangrene
- reduced / absent peripheral pulses
- skin atrophy (chronic disease)
- hair loss (chronic disease)
- cyanosis
- excessive sweating due to overactivity of sympathetic nerves
- erectile dysfunction
Where are “punched out” ischaemic ulcers usually seen?
When do they usually occur?
- usually on the toes and heels
- tend to occur after a localised traumatic event
- often painful, but diabetic and alcoholic patients may not have pain
How can gangrene be identified?
black necrotic gangrenous tissue often surrounds the punched out ulcer lesions
infection of these areas can occur (wet gangrene)
What is the name of the disease that leads to erectile dysfunction in patients with peripheral vascular disease?
Leriche syndrome
this is a type of PVD known as aortoiliac occlusive disease
it involves blockage of the abdominal aorta as it transitions into the common iliac arteries
What is the triad of symptoms associated with Leriche syndrome?
- claudication of the buttocks and thighs
- absent or decreased femoral pulses
- erectile dysfunction
the legs will also appear pale and cold
For what type of patient with PVD is amputation considered?
it may be necessary in patients with severe disease
it is usually only performed in patients with severe unremitting leg pain + gangrene
this is performed to prevent sepsis
How should amputation be performed to provide the best results for the patient?
- amputation should be performed as distally as possible
- ideally it should be below the knee, as this provides the greatest flexibility with prosthetic replacement limbs
- BUT it must be high enough to allow healing of the stump
- in many cases, above the knee amputation is likely to heal better
What medication is given prophylactically to patients who have an amputation and why?
gabapentin
this is used to treat phantom limb pain, which is very common
How is a diagnosis of peripheral vascular disease made?
After a diagnosis is made, where is the patient referred to?
diagnosis can be made on the basis of a suggestive history and examination, in conjunction with an ABPI <0.9
the patient is referred to the vascular team for further investigation, which typically includes a CT angiogram of the lower limb
What is ABPI?
Why is it used in the diagnosis of PVD?
ankle-brachial pressure index
it is a measure of the ratio of the blood pressure in the ankle vs. the arm
PVD affects the legs more than the arms, so it can be used as an indicator of reduced arterial blood flow in the legs
How is ABPI measured in the clinic?
What is a normal value and what value suggests limb ischaemia as a result of PVD?
- measure the BP in both arms and take the highest value
- measure the BP in both legs and take the highest value
(often, instead of a stethoscope, a Doppler ultrasound probe is used to measure the pressure over the posterior tibial artery - record the pressure when you hear the first “whoosh”)
- using only systolic values, divide the ankle pressure by the brachial pressure
A NORMAL VALUE IS >1
A VALUE OF <0.9 IS PATHOLOGICAL FOR LIMB ISCHAEMIA
the lower the number, the greater the degree of PVD
At what ABPI values will there be pain at rest and high risk of gangrene?
- pain at rest - ABPI is equal to or less than 0.6
- high risk of gangrene - ABPI <0.3 or ankle systolic pressure < 55mmHg
Why might false readings for ABPI be obtained in someone with severe atherosclerosis?
in very severe atherosclerosis, the vessels are incompressible
because of this, falsely high readings may be obtained
(e.g. ABPI > 1.3)
What blood tests should be performed in the investigations for PVD?
Why this combination?
- HbA1c
- lipids
- U&Es
- ESR / CRP - to exclude arteritis
- ECG - to check for cardiac involvement
- platelets & clotting
these blood tests form part of the investigation for diabetes
What type of imaging should be performed when investigating PVD?
arterial imaging should be performed to assess the extent of the disease
e.g. CT angiography
What is the main category of differentials for PVD?
- the most likely differential diagnosis is a neurological cause
- this is usually compression of the spinal cord due to spinal stenosis
this is sometimes referred to as neurogenic claudication
- it causes a similar pattern of pain on activity in the buttocks and legs, alleviated by rest
What is the difference in pain patterns in PVD and neurogenic claudication?
PVD:
- pain starts in the calf and radiates UP the leg
Neurogenic claudication:
- pain starts in the buttocks and radiates DOWN the leg
As well as treating the PVD, what are many of the other treatments given aimed at?
a diagnosis of PVD is a confirmation that the patient has cardiovascular disease
as well as treating the PVD, many treatments are aimed at reducing other complications of CVD, such as stroke and MI
What is the aim of PVD treatment?
How is this acheived?
improve the walking distance and lower limb circulation
- there are no medications that improve the symptoms of intermittent claudication
- walking therapies can be as effective as surgery at improving symptoms
What medications should all patients with peripheral vascular disease be given?
STATIN:
- e.g. atorvastatin 40mg nocte
- given this regardless of cholesterol levels
HYPERTENSION MEDICATION:
- this can be an ACE-inhibitor - e.g. ramipril 5mg daily
- or a calcium channel blocker - e.g. amlodipine 5mg daily
ANTIPLATELET AGENT:
- this improves claudication distance & reduces other symptoms
- can be aspirin 100mg daily or clopidogrel 75mg daily
What type of hypertension drug should be avoided in PVD?
beta-blockers
they should be avoided, but are typically safe unless PVD is very severe
What lifestyle recommendations are given to patients with PVD?
- stop smoking
- lose weight and aim for a BMI between 18.5 and 24.9
- increase exercise - e.g. 5x a week for 30-60 minutes
Why is increasing exercise so important for patients with PVD?
it may increase the claudication distance and improve quality of life
it is thought to be beneficial by:
- increasing collateral circulation
-
improving endothelial compliance
- i.e. better vasodilation to overcome the lumen narrowing and improved blood flow
- decreasing blood viscosity
What recommendations are given to patients about walking and exercise?
How many tend to improve through walking therapy?
- walk until it is limited by claudication
- rest until symptoms improve
- after resting, begin to start walking again
- 1/3 of patients will improve, 1/3 stay the same and 1/3 will get worse
What lifestyle advice is given to patients with PVD to help them manage their symptoms?
-
Raise their pillows in bed by 4 - 6 inches
- this keeps the legs below the level of the heart to reduce leg pain at night
- Avoid cold weather if possible
-
Foot care
- encourage self-inspection daily for lesions, with prompt treatment
- careful washing of the feet every day with thorough drying
What measures are in place to control risk factors for PVD?
- screening for and treating diabetes
- patients with known CVD are automatically considered high risk for diabetes
What types of patients have surgery for PVD?
What are the indications for specialist referral?
surgical treatments are reserved for patients with very severe symptoms or where tissue destruction is present
indications for specialist referral include:
- lifestyle-limiting claudication
- pain at rest
- gangrene
What is involved in percutaneous transluminal angioplasty (PTA) and what type of lesions is it useful for?
- useful for short lesions (usually <5cm) in large arteries
- a balloon is used to widen the artery (which is sometimes sufficient on its own)
- in most cases, a stent is also placed in the artery
What type of artery disease is percutaneous transluminal angioplasty (PTA) efficient at treating?
- successful in 75-90% of patients with iliac artery disease
- also successful in 50-70% of patients with thigh and calf disease
How are patients selected for PTA?
What group of patients is it not good for?
patients are selected based on arterial imaging
PTA is NOT good for long lesions - which are more likely to occur in diabetic patients
What is the recurrence rate following PTA?
What are potential complications that may occur after the procedure?
recurrence is about 30% after 3 years
PTA can result in thrombus formation and subsequent embolisation
What type of surgery is performed in patients with PVD?
thromboendartectomy and bypass grafting
What types of patients are usually good candidates for thromboendarterectomy and bypass grafting?
it is only suitable for some patients
these are those with an obvious blockage, where the distal vessel is still filled by collateral vessels
this indicates that the distal vessel is still in good shape
patients must also be able to tolerate surgery and it is sometimes used in those in whom PTA was not successful
What is a bypass graft made of?
they are usually made from venous tissue
prosthetic structures can also be used
What medications are given to patients after surgery depending on whether they have had a venous or a prosthetic graft?
- ASPIRIN improves the longevity / patency of prosthetic grafts
- WARFARIN may be required after graft surgery in venous grafts
What treatment can be used to relieve pain in patients with PVD who are not suitable for surgery?
chemical or surgical sympathectomy
this is usually chemical lumbar sympathectomy that involves destruction of the lumbar sympathetic chain (usually L2 & L3 ganglia)
it has been seen to improve pain and wound healing
In which types of patients is sympathectomy most commonly performed?
it is particularly useful in diabetic patients
When might limb compression be used to help patients with PVD?
this is used to help patients with severe PVD who are not suitable for surgery
inflatable cuffs are placed over the limb and inflated rhythmically for a period of 1-2 hours, several days per week
this is thought to improve both venous & arterial flow, thus reducing symptoms, but evidence is poor
What is the definition of acute limb ischaemia?
the sudden decrease in limb perfusion that threatens the viability of the limb
complete or even partial occlusion of the arterial supply to a limb can lead to rapid ischaemia and poor functional outcomes within hours
What are the 3 main categories of causes of acute limb ischaemia?
- embolisation
- thrombosis in situ
- trauma (less common), including compartment syndrome
How can embolisation lead to acute limb ischaemia?
What conditions are associated with this?
a thrombus from a proximal source travels distally to occlude the artery (most common)
the original thrombus source may be as a result of:
- atrial fibrillation
- post-MI mural thrombus
- abdominal aortic aneurysm
- prosthetic heart valves
What is meant by thrombus in situ?
an atheromatous plaque in the artery ruptures and a thrombus forms on the plaque’s cap
What way is used to remember the classical signs and symptoms of acute limb ischaemia?
!!! REMEMBER THE 6 Ps !!!
- Pain
- Pallor
- Pulselessness
- Paraesthesia
- Perishingly cold
- Paralysis
How does acute limb ischaemia tend to present?
It presents with a sudden onset of the 6 Ps
(most commonly pain, pulselessness & pallor)
What is a sensitive sign of an embolic occlusion that should be looked out for?
a normal, pulsatile contralateral limb
What causes of potential embolisation should be explored in the patient’s history?
- chronic limb ischaemia
- atrial fibrillation
- recent MI (resulting in a mural thrombus)
- symptomatic AAA (ask about back / abdominal pain)
- peripheral aneurysms
What is the risk of a patient with acute limb ischaemia delaying before presenting to hospital?
the later they present to hospital, the more likely that irreversible damage to the neuromuscular structures will have occurred
this will result in a paralysed limb
it is more likely to happen if they present >6 hours after onset of symptoms
What are the differential diagnoses for acute limb ischaemia?
- critical chronic limb ischaemia
- acute DVT
- spinal cord or peripheral nerve compression
What specific blood tests are performed when acute limb ischaemia is suspected?
What other test is needed?
routine bloods, including:
- serum lactate to assess level of ischaemia
- a thrombophilia screen if patient is <50 without known risk factors
- group and save
these should all be taken, along with an ECG
What tests / scans are involved in the initial investigation of acute limb ischaemia?
suspected cases should initially be investigated with bedside Doppler ultrasound scan of both limbs
this is followed by considering a CT angiography
What test will be performed if the limb is considered to be salvageable?
CT arteriogram
this can provide more information regarding the anatomical location of the occlusion and can help decide the operative approach
What are the stages involved in initial management of acute limb ischaemia?
this is a SURGICAL EMERGENCY
complete arterial occlusion willl lead to irreversible tissue damage within 6 hours
- start patient on high-flow oxygen and ensure adequate IV access
- a therapeutic dose heparin (or preferably a bolus dose then heparin infusion) should be initiated as soon as is practical
What classification system is used for acute limb ischaemia?
Rutherford classification
- Type I - viable
- Type IIa - marginally threatened
- Type IIb - immediately threatened
- Type III - irreversible
For which types of acute limb ischaemia is conservative management considered for?
conservative management can only be considered for those with Rutherford I** and **IIa
What is the conservative management for Rutherford Type I and IIa acute limb ischaemia?
How is it monitored?
prolonged course of heparin
patients on heparin require regular assessment to determine its effectiveness through monitoring APPT and clinical review
surgical interventions may be warranted if no significant improvement is seen
For what type of acute limb ischaemia is surgical intervention required for?
surgical intervention is mandatory for cases presenting in Rutherford IIb
What are the surgical options for Rutherford IIb limb ischaemia that is embolic and due to thrombotic disease?
If cause is embolic, the options are:
- embolectomy via a Fogarty catheter
- local intra-arterial thrombolysis
- bypass surgery (if there is insufficient flow back)
If the cause is due to thrombotic disease, the options are:
- local intra-arterial thrombolysis
- angioplasty
- bypass surgery
What is the treatment for Rutherford type III (irreversible limb ischaemia)?
How can this be identified by appearance?
it appears with a mottled non-blanching appearance with hard woody muscles
it requires urgent amputation or taking a palliative approach
Why do most post-operative cases of limb ischaemia require a high level of care?
due to the ischaemia reperfusion syndrome
this describes tissue damage caused when blood supply returns to tissue after a period of ischaemia
What is the main aim of long term management following acute limb ischaemia?
reduction of the cardiovascular mortality risk
this is acheived through promoting regular exercise, smoking cessation and weight loss
What medication is given to patients as part of the long term management following acute limb ischaemia?
ANTI-PLATELET AGENT:
- such as low-dose aspirin or clopidogrel
- they may be started on anticoagulation with warfarin or a DOAC
- any underlying predisposing conditions to the acute limb ischaemia should be treated (e.g. AF)
What is the mortality rate associated with acute limb ischaemia?
- mortality rate of around 20%
- 30-day mortality rate following surgical treatment for acute limb ischaemia is 15%
What is the main complication of acute limb ischaemia?
reperfusion injury
sudden increase in capillary permeability can result in:
- compartment syndrome
- release of substances from the damaged muscle cells, such as:
- K+ ions causing hyperkalaemia
- H+ causing acidosis
- Myoglobin, resulting in significant AKI
