Non-Radio Notes: Cardio-Thoracic-Vascular

ABPI
Ankle-Brachial Pressure Index

0.6 - 0.9: Usually presents with claudication
< 0.5: Usually presents with rest pain and ulceration
Figures can be falsely elevated in Diabetic (DM) patient because calcified tibial vessels

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Complications of Carotid endarterectomy:
Intra-operative:

1. Neurologic deficits due to
1. Embolisation during manipulation
2. Poor flushing technique after closure
2. Cerebral ischaemia
1. Hypotension
2. Poor protection during cross-clamping
3. Haematoma: Ensure airway not compromised
4. False aneurysm formation
5. Cranial Nerve injury
1. CN VIII: Ipsilateral corner of mouth drooping
2. CN IX: Dysphagia
3. CN X: Hoarseness, loss of effective cough
4. CN XII: Ipsilateral deviation of tongue, Difficulty with speech and mastication
6. Superior laryngeal nerve injury: Voice fatigue, loss of high-pitch phonation
7. Hypotension
8. Hypertension: due to 
1. Denervation of carotid sinus
2. Cerebral renin and/or Noradrenaline production
3. Pre-existing hypertension
4. Central neurologic deficit

Post-operative: Neurological injury due to

1. Intimal flap
2. Reperfusion
3. External carotid artery clot

Recurrence of stenosis due to:

1. Myointimal hyperplasia (occurs in the first 24months)

2. Atherosclerosis (occurs after the first 24months)

NOTE:
Anatomical landmark for Carotid artery bifurcation => Facial vein.

After the ICA is occluded, the Periorbital branches of the ECA form communication with the opthalmic artery => re-establish circulation in the circle of Willis.

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Graft occlusion - Fail because of poor inflow / outflow, Structural changes at the anastomosis or of the graft itself.

1. <30 days: Due to technical errors, surgace thrombogenicity with low flow
2. < 18 mth: Due to Myointimal hyperplasia
3. > 18 mth: Venous graft structural changes (eg. Valve site stenosis, segmental fibrosis), aneurysm, new atheromatous changes
4. > 36 mth: Dilation / Aneurysm change in graft

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True aneurysm vs False aneurysm

True aneurysm:
- A localised dilation of an artery covered by all 3 layers

False aneurysm:
- Usually caused by trauma, which disrupts all 3 layers that results in pulsating haematoma covered by fibrous tissue

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Leriche syndrome
Gradual occlusion of terminal aorta. Clinical presentation:

1. Claudication
2. Impotence
3. Lower limb muscular atrophy
4. Trophic changes of the feet
5. Pale legs (Pallor)