Vascular Flashcards
Incidence of chronic limb ischaemia?
5% of males >50 yrs have intermittent claudication
Definition of chronic limb ischaemia?
- Ankle artery pressure <50mmHg (toe <30mmHg)
- And either:
Persistent rest pain requiring analgesia for >2 weeks
Ulceration or gangrene.
Causes of chronic limb ischaemia?
Atherosclerosis
- Typically asymptomatic until 50% stenosis
- Vasculitis and fibromuscular dysplasia are very rare causes.
Atherosclerosis summary - pathophysiology?
- Endothelial injury: haemodynamic, HTN, icnreased lipids.
- Chronic inflammation
- Lipid-laden foam cells produce GFs, cytokines, ROS and MMPs.
- lymphocyte and SMC recruitment.
- SM proliferation: conversion of fatty streak to atherosclerotic plaque.
Difference between Arteriosclerosis and atherosclerosis?
Arteriosclerosis = general arterial hardening Atherosclerosis = Arterial hardening specifically due to atheroma
Atheroma pathology?
Fibrous cap: SM cells, lymphocytes, collagen
Necrotic centre: Cell debris, cholesterol, Ca, foam cells.
Risk factors for chronic limb ischaemia?
Modifiable: Smoking, BP, DM control, hyperlipidaemia, decreased exercise.
Non-modifiable: FH and PMH, Male, increased age, genetic.
Associates vascular diseases with chronic limb ischaemia?
IHD: 90% Carotid stenosis: 15% AAA. Renovascular disease. DM microvascular disease.
Presentation of chronic limb ischaemia?
Intermittent claudication
- Cramping pain after walking a fixed distance
- Pain rapidly relieved by rest
- Calf pain = superficial femoral disease (commonest)
- Buttock Pain = Iliac disease
What is the presentation of critical limb ischaemia?
Fontaine 3-4
1 or more of: Rest pain - Especially @ night - >2 weeks - Usually felt in the foot - Not helped by analgesia - Pt hangs foot out of bed - Due to decreased CO and loss of gravity help.
Ulceration
Gangrene
What is Leriche’ syndrome?
Leriche’s syndrome: aortoiliac occlusive disease
- Atherosclerotic occlusion of abdominal aorta and iliacs
Presents with triad
- Buttock claudication and wasting
- Erectile dysfunction
- Absent femoral pulses
What is Buerger’s Disease?
Thomboangiitis Obliterans
- Young, male heavy smoker
- Acute inflammation and thrombosis of arteries and veins in the hand and feet.
- Leads to ulceration + gangrene.
Signs of chronic limb ischaemia?
Pulses: Pulse and increased CRT (normall <2sec)
- Ulcers: painful, punched out, on pressure points.
- Nail dystrophy/onycholysis.
- Skin:cold, white, atrophy, absent hair.
- Venous guttering (veins collapse)
- Muscle atrophy
Decreased Buerger’s Angle
- >90: normal
- 20-30: ischaemia
- <20: Severe ischaemia.
+ve Buerger’s Sign - Reactive hyperaemia due to accumulation of deoxygenated blood in dilated capillaries.
What is Buerger’s test?
Patient is positioned supine.
Standing at bottom of bed, raise both of the patient’s feet to 45 degrees for 2-3mins.
- Look for pallor - Note at what angle this occurs. If less than 20 degrees indicates severe limb ischaemia.
Then drop leg over side.
- Look for reactive hyperaemia.
Clinical classification? - Fontaine?
- Asymptomatic
- Intermitted claudication
a. >200m
b. <200m - Ischaemic rest pain
- Ulceration/gangrene
What is the rutherford classification?
Mild claudication Moderate claudication Severe claudication Ischaemic rest pain Minor tissue loss Major tissue loss.
What are the investigations for chronic limb ischaemia?
Doppler Waveforms
- Normal: triphasic
- Mild stenosis: biphasic
- Severe stenosis: monophasic
What if ABPI is high? >1.4
Calcification: CRF, DM
>1.4 . Diabetes leading to high ABPI. Neuropathic and duplex shows its normal.
Can use toe pressure <30mmHg.
What is normal ABPI?
> or equal to 1.
What is asymptomatic ABPI?
Fontaine 1: 0.8-0.9
What is claudication ABPI?
Fontaine 2: 0.6-0.8
What is rest pain ABPI?
Fontaine 3: 0.3-0.6
What is ulceration and gangrene ABPI?
Fontaine 4 <0.3.
Walk Test
Walk on treadmill @ certain speed and incline to establish max claudication distance.
ABPI measured before and after: 20% decreased is significant
Bloods for chronic limb ischaemia?
FBC, U+E, lipids + glucose, ESR: arteritis, G+S: possible procedures.
Imaging for Chronic limb ischaemia?
Assess site, extent and distal run-off.
- Colour duplex US
- CT/MR angiogram: gadolinium contrast.
- Digital subtraction angiography
Invasive therefore not commonly used. USed when performing therapeutic angioplasty or stenting.
May also do ECG looking for ischaemia.
What is the conservative management of chronic limb ischaemia?
- Most patients with claudication can be managed conservatively
- Increased exercise and employ exercise program - very important.
- Stop smoking - must quite smoking.
- Weight loss
- Foot care
Medical management of chronic limb ischaemia
- Risk factors: BP, Lipids, DM
B-B don’t worsen intermittent claudication but used with caution in CLI. - Atorvastatin 80mg regardless of baseline cholesterol.
- Anti-platelets:
clopidogrel (75mg) over aspirin - Analgesia: may need opiate
- parenteral prostanoids decreased pain in patients unfit for surgery.
Can use naftidrofuryl oxalate: vasodilator, sometimes used for patients with a poor quality of life.
Cilostazol: phosphodiesterase III inhibitor - not recommended.
What is the endovascular management of chronic limb ischaemia?
Percutaneous Transluminal Angioplasty ± stenting.
Good for short stenosis in big vessels: E.g iliacs, SFA.
Lower risk for patients: performed under LA as day case.
Improved inflow –> decreased pain but restoration of foot pulses is required for Rx of ulceration/gangrene.
What are the surgical reconstruction used in chronic limb ischaemia?
Indications
- V.short claudication distance (e.g <100m)
- Symptoms greatly affecting pts QoL
- Development of rest pain.
- Critical limb ischaemia should cannot have angioplasty.
- Pre-op: need good optimisations as likely to have cardioresp co-morbidities.
- Practicalities: need good proximal supply and distal run-off. Saphenous vein grafts preferred below the IL. More distal grafts have increased rates of thrombosis.
What is the classification of surgical reconstructions?
Anatomical: fem-pop, fem-distal, aortobifemoral.
Femoral popliteral bypass.
Extra-anatomical: axillo-fem/ bifem, fem-fem crossover.
What other surgery can be used for chronic limb ischaemia?
Endarterectomy: core-out atheromatous plaque
Sympathectomy: chemical (etoh) or surgical.
Amputation.
What is the prognosis of chronic limb ischaemia?
1 yr after onset of CLI
- 50% alive without amputation
- 25% will have had major amputation
- 25% dead (MI/Stroke).
What is acute limb ischaemia?
Acute: ischaemia <14d
Acute on chronic: worsening symptoms and signs <14 d
Chronic: ischaemia stable for >14 days.
Severity of acute limb ischaemia ?
- Incomplete: Limb not threatened
- Complete: limb threatened
Loss of limb unless intervention within 6hrs. - Irreversible: requires amputation
Causes of acute limb ischaemia?
Thrombosis in situ (60%)
- A previously stenosed vessel with plaque rupture.
- Usually incomplete ischaemia
Embolism
- 80% from LA in AF
- Valve disease
- Iatrogenic from angioplasty/surgery
- Cholesterol in long bone fracture
- Paradoxical (venous via PFO)
- Often complete ischaemia
Graft/stent occlusion
Trauma
Aortic dissection
Presentation: 6Ps
Pale Pulseless Perishingly cold Painful Parasethesia Paralysis
Difference between a thrombosis and embolus?
Thrombosis = hrs to days. - is less severe - History of claudication - Contralateral pulses absent - Diagnosed on angiography - Thrombolysis management and bypass surgery.
Embolus
- Sudden
- Profound ischaemia
- Present with AF
- Absent claudication hx
- present contralateral pulses
- Diagnosed clinically
- Manage = Embolectomy + warfarin.
Investigations for acute limb ischaemia?
Blood
- FBC, U+E, INR, G+S
- CK
ECG
Imaging
- CXR, Duplex Doppler
General management of acute limb ischaemia?
- In an acutely ischaemic limb discuss immediately with a senior as time is crucial.
- NBM
- rehydration: IV fluids
- Analgesia: morphine + metoclopramide
- Abx: e.g augmentin if sings of infection
- Unfractionated heparin IVI: prevents extension
Is there complete occlusion
- Yes: urgent surgery: embolectomy or bypass.
- No- angiogram + observe for deterioration.
When is angiography performed?
Not performed if there is complete occlusion as it introduces delay: take straight to theatre
If incomplete occlusion, pre-op angio will guide any distal bypass.
Management of an embolism?
- Embolectomy
- Under LA or GA
- Wire fed through embolus
- Fogarty catheter fed over the top
- Balloon inflated and catheter withdrawn to remove embolism.
- Send embolism for histo (exclude atrial myxoma)
- Adequacy confirmed by on-table angiography. - Thrombolysis
Consider if embolectomy unsuccessful
- E.g local injection if TPA
Other option
- Emergency reconstruction
- Amputation
Post embolectomy
- Anticoagulate: heparin IVI –> warfarin
- ID embolic source : ECG, echo, US aorta, fem and pop
Complications - Reperfusion injury Local swelling --> compartment syndrome Acidosis and arrhythmia 2ndry to increased K ARDS GI oedema --> endotoxic shock.
Chronic pain syndromes.
Management of thrombosis?
- Emergency reconstruction if complete occlusion
- Angiography + angioplasty
- Thrombolysis
- Amputation
Carotid artery disease definition?
Stroke: Sudden neurological deficit of vascular origin lasting >24hrs
TIA: sudden neurological deficit of vascular origin lasting <24hrs (usually last <1hr) with complete recovery.
What is the pathogenesis of carotid artery disease?
Turbulent flow –> decreased shear stress at carotid bifurcation promoting atherosclerosis and plaque formation.
Plaque rupture –> complete occlusion or distal emboli.
Cause 15-25% of CVA/TIA
Investigations of carotid artery disease?
Duplex carotid doppler
MRA
Management of Carotid artery disease?
Conservative
- Aspirin or clopidogrel
- Control risk factors
Surgical: Endarterectomy - Symptomatic >70% (5% stroke risk) >50% if low risk (<3%) Perform with 2week of presentation
Asymptomatic
- >60% benefit if low risk