Peripheral vascular disease and aneurysms September 2025
Learning outcomes 1. List the aetiological features of peripheral vascular disease. 2. List the vessels commonly affected by peripheral vascular disease. 3. Describe the changes occurring in the blood vessels in peripheral vascular disease. 4. Correlate the clinical features of peripheral vascular disease with the pathological changes occurring in the blood vessels. 5. Describe the complications of peripheral vascular disease. 6. Define an aneurysm. 7. List the different types of aneurysms. 8. Describe the pathological mechanisms involved in the formation of aneurysms including arterio-venous fistulae. 9. Describe the clinical effects and complications of aneurysms.
Peripheral Arterial Disease is a term used to describe narrowing and occlusion of arteries outside the brain and heart. This can involve carotid vessels, mesentric vessels, renal vessels and vessels of the upper and lower limbs. LEAD (lower extremity arterial disease) is the acronym used to describe a collection of symptoms and signs associated with lower limb arterial occlusion PVD – peripheral vascular disease Commonly caused by atherosclerosis Acute or chronic
Arterial stenosis is commonly cased by atheroma, but can also occur acutely as a result of emboli and trauma. Which of the following are major risk factors for atheresclerosis ? Cigarette smoking Obesity Hypertension Hyperlipidemia Diabetes
Other risk factors for atherosclerosis Non Modifiable - Family history, male gender, genetic abnormalities, Age Modifiable- Inflammation, hyperhomocysteinemia , metabolic syndrome, stress, physical inactivity
Vascular response to injury Vascular injury associated with endothelial cell dysfunction or loss stimulates smooth muscle cell recruitment and proliferation and associated extra cellular membrane synthesis; the result is intimal thickening that can compromise vascular flow
Spectrum of vascular pathology in PAD- 1 A1 - Normal artery A2 - adaptive intimal thickening with focal calcification of the internal elastic lamina (arrow)
Spectrum of vascular pathology in PAD- 2 A4 - shows a fibroatheromatous plaque ( blue arrow points to necrotic core) with medial calcification (black arrow) involving more than three-fourths of the circumference of the artery. A5 - fibrocalcific plaque (blue arrow) and medial calcification (black arrow) involving more than three-fourths of the circumference
Spectrum of vascular pathology in PAD- 3 B1- Adaptive intimal thickening (blue arrow) and an acute luminal thrombus (black arrow) . Circumferential medial calcification (red arrow) is present. B2- Shows an organizing thrombus with residual fibrin (black arrow) ; adaptive intimal thickening is present (blue arrow)
Features of lower limb chronic arterial stenosis or occlusion Intermittent claudication Rest pain Coldness, numbness, parasthesia , colour change Ulceration and gangrene Temperature is that of surroundings Sensation decreased Movement lost of diminished Arterial pulsation decreased or absent Arterial bruits
Intermittent claudication "Claudication" = limp - The Roman emperor Claudius walked with a limb, possibly due to poliomyelitis Cramp like pain felt in the muscle Not present when taking first step Brought about by exercise Pain disappears when exercise is stopped
Relationship of site of pain to the site of disease
Rest pain - Severe pain felt in the foot at rest, made worse by lying down or elevation of the foot. Indicates severe ischemia Coldness numbness and parathesia - Common in moderate as well as sever ischaemia Colour changes - Moderate or severely ischaemic limbs become blanched on elevation and develop a purple discoloration on dependency Pre gangrene - The combination of rest pain, colour changes, oedema and hyperaesthesia , with or without ischaemic ulceration, is frequently referred as pregangrene Ulceration and gangrene Impotence - Failure to achieve an erection is often a feature in male patients with an occlusion in the region of the bifurcation of the aorta and the internal iliac arteries ( Leriche’s syndrome).
Investigation of arterial occlusive disease When to investigate? Invasive vs Non invasive What is the purpose of investigation? General investigations Doppler ultrasound - ABPI Duplex scanning Digital substraction angiography
Aneurysms
What is an aneurysm? A permanent , localized abnormal dilatation of a blood vessel (or heart)
Why do aneurysms occur??? Aneurysms result when integrity of the vessel wall is lost Due to Compromised structure and function of connective tissue within the vessel wall
Aneurysms can be life threatening Why ? They can rupture and bleed Abdominal aortic aneurysms Thoracic aneurysms Cerebral aneurysms They lead to thrombo- embolic events Cardiac aneurysms
Other clinical effects of aneurysms Compression of neighboring structures Obstruction of vessel branching off from aorta Alteration of the flow of blood
What are true and false aneurysms?
True aneurysms Involves all the layers of an intact , but attenuated wall
False aneurysm There is a defect in the arterial wall Leading to the formation of an extra- vascular haematoma which communicates with the intravascular space
Classification by shape and size Fusiform & saccular aneurysms Fusiform aneurysm Diffuse, circumferential dilatation of a long vascular segment Saccular aneurysm Spherical outpouching involving only a portion of the vessel wall Often contain thrombi
Normal vessel True aneurysm Saccular True aneurysm Fusiform False aneurysm
Aneurysms - pathogenesis
Weakening of arterial wall - mechanisms Connective tissue disorders Marfans syndrome - defective fibrillin leading to weakening of elastic tissue Ehler- Danlos syndrome defective type III collagen synthesis Loeys- Dietz syndrome Defective elastin, collagen I & III Vitamin C deficiency defective cross linking of collagen
Weakening of arterial wall - mechanisms Increased collagen degradation - conditions of increased proteolytic production enzyme ( eg : MMP vs TIMMP ) atherosclerosis vasculitis infections Degrade all components of the ECM in the arterial wall
Weakening of arterial wall – mechanisms Loss of vascular smooth muscle Atherosclesosis : ischemic effects Hypertension – intimal thickening and narrowing of vasa vasorum Syphillis - narrowing of vasa vasorum (endarteritis obliterans) Such ischemia results in SMC loss as well as aortic “ degenerative changes ”
A neurysm formation in atherosclerosis 1 Plaque within intima Compression of media Medial ischemia Medial degeneration & Weakening 2 Inflammatory cells within the plaque Production of MMP Collagen degeneration Weakening of vessel wall
Weakening of arterial wall – mechanisms Degenerative changes: Fibrosis (replacing distensible elastic tissue) Inadequate ECM synthesis Accumulation of amorphous ground substance Histologically, these changes are called “ cystic medial degeneration”
Weakening of arterial wall – mechanisms Cystic medial degeneration is nonspecific; They can also occur whenever ECM synthesis is defective, Eg: Marfan syndrome and scurvy
Causes of weakening of arterial wall Connective tissue disorders Atherosclerosis Hypertension Vasculitis Syphillis Other infections ( mycotic aneurysms) Trauma Myocardial infarction (Heart) Fibromuscular dysplasia – Berry aneurysms
The two most important causes of aortic aneurysm formation are Atherosclerosis & Hypertension Other causes Marfan syndrome Loeys- Dietz syndrome Ehlers- Danlos syndrome Vasculitis Connective tissue disorders
Abdominal aortic aneurysms - AAA Mostly in men & smokers Usually after 50 years Usually due to atherosclerosis Commonly infra- renal location just above the bifurcation of aorta S accular/fusiform Risk of rupture increases with size Mycotic AAA – chance of rapid dilation & rupture Clinical feature s- Rupture, embolism, obstruction, impingement
Abdominal aortic aneurysms - AAA
Thoracic aortic aneurysms Most commonly associated with hypertension , syphillis Expanding aneurysm Compression of lungs & airways Respiratory insufficiency Compression of oesophagus Difficulty in swallowing Irritation of recurrent laryngeal nerves Persistant cough Erosion of bone Bone pain Aortic valve Disease/ narrowing of Coronary ostia Cardiac disease
Berry aneurysm Classically occurs in the Circle of Willis Sometimes referred to as congenital aneurysms, but are not present at birth Develop because of underlying defects of media
Berry aneurysm
The most common site of involvement of atherosclerotic aneurysm is…. Arch of aorta Thoracic aorta Supra- renal abdominal aorta Infra- renal abdominal aorta
This is an aneurysm of the humeral artery that occurred in a child who suffered from a displaced supracondylar fracture 6 months ago
What type of an aneurysm is this? What are the other causes of false aneurysms? After peripheral artery bypass surgery at the site of anastomosis Following trauma Arterial leakage after removal of cannulae
Aortic dissection Aortic dissection occurs when blood separates the laminar planes of the media to form a blood-filled channel within the aortic wall Causes Hypertension – 90% cases Connective tissue diseases – E.g Marfan syndrome Iartogenic Pregnancy
Aortic dissection Clinical features Sudden onset chest pain….. Cardiac tamponade Aortic disfunction Vascular obstruction and ischemic consequences
Learning outcomes 1. List the aetiological features of peripheral vascular disease. 2. List the vessels commonly affected by peripheral vascular disease. 3. Describe the changes occurring in the blood vessels in peripheral vascular disease. 4. Correlate the clinical features of peripheral vascular disease with the pathological changes occurring in the blood vessels. 5. Describe the complications of peripheral vascular disease. 6. Define an aneurysm. 7. List the different types of aneurysms. 8. Describe the pathological mechanisms involved in the formation of aneurysms including arterio-venous fistulae. 9. Describe the clinical effects and complications of aneurysms.