Peripheral Vascular Disease Flashcards
What is PVD?
-When peripheral arteries (excluding the coronary or cerebral vessels)
-Are abnormally narrowed or blocked
-Causing reduced blood flow
PVD Epidemiology
-70+ more females/ 1 in 6 have PVD
-Increasing age= increasing prevalence
-Common
Pathogenesis of atherosclerosis
-Fatty streaks accumulate under innermost subendothelial layer
=Inflammatory response
=Smoking and hypertension aggravate plaque
- Quiescent disease= artery heals and calcification replaces organic materials in wall, arteries left narrow
- Active disease= ruptured plaque, aggressive thrombosis- narrows blood vessel/ occlude (thrombosis in situ)
=new fibrous plaque leads to narrowing
=Necrotic core and thickened fibrous plaque which is dense in calcium
PVD risk factors
-Smoking
-Advancing age
-High cholesterol
-Obesity
-DM
-CKD
Describe the process of collateralisation
-Narrow artery= less blood flow
-Tissue artery is supplying becomes starved of blood
=Release growth factors to stimulate angiogenesis (physiological response to hypoxia)
=Compensatory mechanism to maintain end organ perfusion
=Smaller, more tortuous as natural bypass
What is involved in the clinical assessment of PVD?
-How severe is the ischaemia?
-Where is the obstructive lesion?
-How fit is the patient?
=Blood tests
=Radiology
Signs of critical limb ischaemia
-Intermittent claudication (100m exercise threshold)
-Sunset Red foot: Buerger’s Test to differentiate from cellulitis (hypoxic- vasodilation)
-Rest pain relieved by hanging foot, out of bed at night (gravity)
-Tissue loss- gangrene or ulcers
-Infection/ pus
What is the Ankle Brachial Pressure Index?
ABPI= Ankle pressure (pressure at which pedal doppler signal appears)/ brachial pressure= determines severity
> 12= uncompressible vessels
1.2-0.9= normal
0.8-0.6= moderate PVD
<0.5= severe PVD (critical limb ischaemia)
-Can be raised in calcified vessels as cannot be compressed so very severe
What arteries are in the aorto-iliac segment?
-Aorta
-Common iliac artery
-External iliac artery (leg)
-Internal iliac artery (pelvis)
What arteries are in the femoro-popliteal segment?
-Common femoral artery (previously external iliac at groin)
-Profunda femoris artery
-Superficial femoral artery
-Popliteal
What arteries are in the crural segment?
-Anterior tibial
-Posterior tibial
-Peroneal (to ankle)
Findings of aorto-iliac segment disease
-Aortic heard
-Dimished/absent femoral, popliteal, dorsalis pedis (dorsum between 1st and 2nd metatarsals) and posterior tibial pulse (behind medial malleolus)
Findings of femoro-popliteal segment disease
-Cannot hear popliteal, dorsalis pedis and posterior tibial pulse
Arterial imaging for PVD
-Arterial Duplex/ doppler ultrasound (arterial tree, blood flow through vessel; velocity increases in stenosis but volume of blood decreases)
-CT angiogram (radiation and contrast agents- calcification)
-MR angiogram (smaller arteries, crural)
-Digital subtraction angiography
Medical therapy for PVD
-Stop smoking
-Antiplatelet agent (aspirin or clopidogrel)
-Statin
-Blood pressure control
-DM control
-No calf compression
Surgical therapies for PVD
-Endovascular therapy
=Percutaneous balloon angioplasty
=Stent
-Endarterectomy
=Remove atherosclerotic plaque (common femoral artery or carotid artery in stroke patients, with small blockage)
-Bypass surgery
=Anatomical: aorto-femoral bypass (fit patient), femoro-popliteal (saphenous vein or synthetic)
=Extra-anatomical: femoro-femoral bypass, axillofemoral bypass
-Major limb amputation
=below knee: femoro-popliteal or crural segment occlusions
=above knee: aorto-iliac segment occlusions
What are arterial ulcers?
-Occur on the toes and heel/ dorsum of foot
-Typically have a ‘deep, punched-out’ appearance
-Painful, worse at night and improved by lowering leg- smaller and deeper than venous ulcers
-There may be areas of gangrene, can be pale due to poor blood supply
-Cold with no palpable pulses
-Low ABPI measurements, associated with PAD
Investigation and management of arterial ulcers
-ABPI
-Blood tests= infection and DM, albumin and anaemia
-Surgical revascularisation
Presentation of venous leg ulcers
-Features of venous insufficiency: oedema, brown pigmentation, lipodermatosclerosis, eczema
-Location above the ankle, painless, irregular gently sloping border
-Gaiter area (between top of foot and bottom of calf muscle)
-Larger, more superficial than arterial ulcers
-Pain relieved by elevation and worse on lowering leg
Investigation of venous ulcers
Doppler ultrasound looks for the presence of reflux and duplex ultrasound looks at the anatomy/ flow of the vein
Management of venous ulcers
-4 layer compression banding after exclusion of arterial disease or surgery
-If fail to heal after 12 weeks or >10cm2 skin grafting may be needed
Difference between deep and superficial venous insufficiency
Deep venous insufficiency is related to previous DVT and superficial venous insufficiency is associated with varicose veins
