Coronary Artery Disease

Question 1

What is coronary artery disease (CAD)?

Answer 1

Carotid artery disease refers to the build-up of atherosclerotic plaque in one or both common and internal carotid arteries, resulting in stenosis or occlusion.

Question 2

What % of ischemic strokes is due to CAD?

Answer 2

10-15% of ischaemic strokes are due to plaque rupture and/or atheroembolism.

Question 3

Briefly describe the pathophysiology of CAD

Answer 3

The pathophysiology of carotid artery disease is as for atheroma elsewhere, starting with a fatty streak, accumulating a lipid core and formation of a fibrous cap. The turbulent flow at the bifurcation of the carotid artery predisposes to this process specifically at this region.

Question 4

Briefly describe the classification of degree of carotid stenosis depending on diameter reduction

Answer 4

Mild: <50%

Moderate: 50-69%

Severe: 70-99%

Total Occlusion: 100%

Question 5

What are the risk factors of CAD?

Answer 5

The major risk factors for carotid artery disease are age (≥65 years), smoking, hypertension, hypercholesterolaemia, obesity, diabetes mellitus, history of cardiovascular disease, and a family history of cardiovascular disease.

Question 6

What are the clinical features of CAD?

Note: signs and symptoms

Answer 6

Carotid artery disease will often be asymptomatic, however may present as a focal neurological deficit. This can take one of two forms:

• Transient ischaemic attack (TIA)
• Stroke

Question 7

What are the clinical features of CAD?

Note: examination

Answer 7

On examination of the vascular system, a carotid bruit may be auscultated in the neck (however this is associated with carotid stenosis in less than half of cases).

Question 8

Why is carotid stenosis (even with complete occlusion) likely to be asymptomatic?

Answer 8

Carotid stenosis (even with complete occlusion) is likely to be asymptomatic if unilateral. This is due to collateral supply from the contralateral internal carotid artery and the vertebral arteries, via the Circle of Willis.

Question 9

What investigations should be ordered for any patient suspected of ischaemic (or haemorrhagic) stroke?

Note: initial investigations

Answer 9

Any patient suspected of ischaemic (or haemorrhagic) stroke should have an urgent non-contrast CT head scan, assessing for evidence of infarction potentially amenable to thrombolytic treatment.

Other investigations for a patient admitted with a stroke include:

• Bloods, including FBC, U&Es, clotting, lipid profile and glucose
• ECG (especially to check for atrial fibrillation)

If thrombectomy is considered in patients with evidence of ischaemia, imaging via CT head contrast angiography is also required.

Question 10

What investigations should be ordered for any patient suspected of ischaemic (or haemorrhagic) stroke?

Note: follow up

Answer 10

Once a diagnosis of ischaemic stroke or TIA is made, it is important to screen the carotid arteries for disease precipitating the presentation. This can be done initially with Duplex ultrasound scans, which gives a good estimate as to the degree of stenosis, as well as excluding any other possible differentials.

Lesions within the carotid artery may then be further characterised via CT angiography, which gives a more accurate assessment of the diseased portion of the vessels prior to any potential surgery.

Question 11

Briefly describe the acute management for suspected stroke

Answer 11

All patients admitted with a suspected stroke should be started on high flow oxygen and blood glucose optimised (target 4-11mmol); a swallowing screen assessment should also be made on admission.

Initial management depends on the nature of the stroke:

• Ischaemic stroke: IV alteplase (r-tPA), if patients are admitted within 4.5hrs of symptom onset and meet inclusion criteria, and 300mg aspirin (orally, or rectal if dysphasic)
• Haemorrhagic stroke: correction of any coagulopathy and referral to neurosurgery (for potential clot evacuation)

Thrombectomy is indicated in patients with confirmed acute ischaemic stroke and confirmed occlusion of the proximal anterior circulation on angiography, as well as consideration for intravenous thrombolysis too.

Question 12

Briefly differentiate between the acute treatment of ischemic or haemorrhagic stroke

Answer 12

Ischaemic stroke: IV alteplase (r-tPA), if patients are admitted within 4.5hrs of symptom onset and meet inclusion criteria, and 300mg aspirin (orally, or rectal if dysphasic).

Haemorrhagic stroke: correction of any coagulopathy and referral to neurosurgery (for potential clot evacuation).

Question 13

Briefly describe the long-term management of suspected stroke

Answer 13

All patients with a known stroke or TIA should also be started on cardiovascular risk factor management.

A referral to the Speech and Language Therapy (SALT) team is advised for any dysphagia or dysphasia. Physiotherapy and Occupational Therapy input is advised for any ongoing mobility issues, with many stroke patients requiring rehabilitation.

Question 14

What is cardiovascular risk factor management?

Answer 14

• Anti-platelet therapy long term, typically aspirin 300mg OD for two weeks, then clopidogrel 75mg OD
  
  • If not tolerated, trial combination therapy aspirin and dipyradimole
• Statin therapy, ideally high-dose atorvastatin (started after the hyperacute phase)
• Aggressive management of hypertension and/or diabetes mellitus
• Smoking cessation
• Regular cardiovascular exercise and active lifestyle with weight loss

Question 15

When is referral to Speech and Language Therapy (SALT) needed?

Answer 15

A referral to the Speech and Language Therapy (SALT) team is advised for any dysphagia or dysphasia.

Question 16

When is referral to physiotherapy and occupational therapy needed?

Answer 16

Physiotherapy and Occupational Therapy input is advised for any ongoing mobility issues, with many stroke patients requiring rehabilitation.

Question 17

When should patients be referred for carotid endarterectomy (CEA)?

Answer 17

All patients with an acute non-disabling stroke (or transient ischaemic attack) who have symptomatic carotid stenosis between 50-99% should be referred for assessment for a carotid endarterectomy (CEA).

Question 18

What is a carotid endarterectomy (CEA)?

Answer 18

CEA involves removing the atheroma and associated damaged intima, thereby reducing the risk of future strokes or TIAs.

Question 19

What are the risks of CEA?

Answer 19

The main risks of CEA surgery are stroke (2-3%), nerve damage to the hypoglossal, glossopharngeal, or vagus nerve, myocardial infarctions, local bleeding, and infection.

Question 20

What nerves can be damaged in CEA?

Answer 20

1. Hypoglossal
2. Glossopharngeal
3. Vagus nerve

Question 21

What is the mortality risk of CAD?

Answer 21

Mortality of a stroke is 12% at 7 days and 19% at 30 days.

Question 23

What are the complications of a stroke?

Answer 23

Complications of a stroke include dysphagia, seizures, ongoing spasticity, bladder or bowel incontinence, depression, anxiety or cognitive decline.

Question 24

What differentials should be considered for CAD?

Answer 24

1. Aortic dissection
2. Thrombotic occlusion of carotid artery
3. Fibromuscular dysplasia
4. Vasculitis

Noncerebrovascular conditions e.g. hypoglycaemia, Todd’s paresis, subdural haematoma, space-occupying lesion, venous sinus thrombosis, post-ictal state and multiple sclerosis.

Question 25

How does CAD and aortic dissection differ?

Answer 25

Patients are often younger (<50yrs) and have an underlying connective tissue disease, with the event potentially precipitated by trauma or sudden neck movement.

Question 26

How does CAD and thrombotic occlusion of carotid artery differ?

Answer 26

Thrombus can only be differentiated from atheromatous plaque on imaging and will present clinically as for atheroma.

Question 27

How does CAD and fibromuscular dysplasia differ?

Answer 27

This is non-atheromatous stenotic angiopathy causing hypertrophy of the vessel wall, predominantly affecting young (<50yrs) females and, whilst most commonly in the renal arteries, the carotid arteries can be affected, presenting clinically with focal neurological deficit.

Question 28

How does CAD and vasculitis differ?

Answer 28

Various great vessel vasculitidies, such as Giant Cell Arteritis or Takayasu’s Arteritis, can cause carotid stenoses, however patients typically have systemic symptoms and other vessels may be affected.