General approach to peripheral arterial disease Flashcards
Peripheral ARTERIAL disease
= disease of all arteries outside of coronary arteries and aorta
Peripheral ARTERY disease
= disease of lower extremities
LEAD: lower extremity arterial disease
Prognostic clinical signs
Individuals with carotid bruits have twice the risk of MI and CV death as compared with those without.
Interarm blood pressure (BP) asymmetry (>15mmHg) is a marker of vascular disease risk and death
A femoral bruit is an independent marker for ischaemic cardiac events.
Technique for measuring ABPI
Supine position
Place manual blood pressure cuff at ankle after 5-10 minutes of rest
Use doppler probe 5-10MHz
Use handheld doppler to find signal at anterior tibial and then posterior tibial
Inflate the cuff until signal is lost, slowly deflate cuff until signal returns - record as systolic BP
Divide brachial pressure by ankle pressure = ABPI
For lower extremity arterial disease, take the LOWEST value of the two legs
Indications for ABPI
Patients with clinical suspicion of LEAD
e. g. abolition of pulse
e. g. arterial bruit in lower limb
e. g. typical history of intermittent claudication
e. g. non-healing lower limb wound
Patients AT-RISK of LEAD, i.e. the following conditions:
- Any other atheroscleortic disease e.g. coronary artery disease
- Screen heart failure patients
- AAA
- CKD
Asymptomatic patients that are AT-RISK for the following reasons:
- Age >65 years old
- High-risk of CVD as per ESC guidelines
- Age >50 with family history of LEAD
Value of ABPI
The ABI is a non-invasive tool useful for the diagnosis and surveillance of LEAD
Strong marker of generalized atherosclerosis and CV risk
-An ABPI <0.90 is associated with 2-3 fold increase in CV related death
What is Duplex
Duplex ultrasound is a non-invasive imaging modality that uses:
- b-mode echography
- pulsed wave, continuous, colour doppler
Allows detection and localisation of vascular lesions and assessment of the severity of stenosis through flow velocity measurement
When to use digital subtraction angiography
Classically considered gold standard investigation but largely replaced by non-invasive imaging modalities such as CT angiogram and duplex ultrasound
Still has a place in below-the-knee vessel investigation and when direct intervention planned
Advantages and disadvantages of CT angiogram
Advantages:
- rapid non-invasive acquisition
- wide availability
- high resolution and 3D reformatting.
- less artefact with movement and respiration
- able to delineate intraluminal and extraluminal features i.e. aneurysm sac
- displays a ‘roadmap’ of the vascularization, essential for determining interventional strategies
Disadvantages
- lack of functional and haemodynamic data
- radiation exposure
- uses iodinated contrast which is nephrotoxic and some patients have anaphylaxis
Advantages and disadvantages of magnetic resonance angiography
Advantages:
- valuable in patients with mild-to-moderate CKD
- good soft tissue imaging
- does not require iodinated contrast
Disadvantages
- nephrogenic systemic fibrosis post gadolinium is more common than firs t appreciated, renal function at time of scan important
- movement artefact
- lack of availability
- contraindications include non-compatible pacemakers and implantable cardioverter defibrillators
- underestimates vascular calcification
- cannot evaluate endovascular stents
Lipid lowering aims in peripheral arterial disease
Give statin and aim for
-LDL cholesterol <1.8mmol/L
OR
> 50% reduction in LDL cholesterol if original levels 1.8 - 3.5 mmol/L
Benefits
- Reduced mortality
- Reduces stroke risk
- Reduced CV events
Combination treatment with ezetimibe in selected patients is also beneficial
Blood pressure control in peripheral arterial disease
Aim for <140/90 mmHg
In diabetics, aim <140/85 mmHg
ACE-inhibitors and angiotensin receptor blockers have further benefits and should be used
-decrease MACE
B-blockers are safe to use in LEAD unless chronic limb-threatening ischaemia present
Don’t over-treat BP, outcomes are worse in LEAD if BP <110 (j-shaped relationship)
Overview of best medical therapy
Smoking cessation is recommended in all patients with PADs - grade IB
Healthy diet and physical activity are recommended for all patients with PADs. - grade IC
Statins are recommended in all patients with PADs. - grade IA
In patients with PADs, it is recommended to reduce LDL-C to < 1.8 mmol/L (70 mg/dL) or decrease it by >_ 50% if baseline values are 1.8–3.5 mmol/L (70–135 mg/dL) - grade IC
In diabetic patients with PADs, strict glycaemic control is recommended.- grade IC
Antiplatelet therapy is recommended in patients with symptomatic PADs - grade IC
In patients with PADs and hypertension, it is recommended to control blood pressure at < 140/90 mmHg.-grade IA
ACEIs or ARBs should be considered as first-line therapyc in patients with PADs and hypertension - grade IIaC
