Vascular Flashcards
What is the most common cause of acute limb ischaemia?
Thrombosis of pre-existing site of atherosclerosis
Acute thrombosis of popliteal aneurysms poses the greatest threat to the limb
Describe the timeline of acute limb iscahemia
< 6 hours - white leg
6-12 hours - mottled, blanching onpressure
12-24 - fixed mottling
How does treatment correlate to appearance of limb?
White leg with sensorimotor - surgery and embolectomy
Dusky leg, mild anaesthesia - Angiography
Fixed mottling - primary amputation
Describe the role of thrombolysis in acute limb ischaemia
Intra arterial thrombolysis is better than peripheral thrombolysis
Mainly indicated in acute on chronic thrombosis
Avoid if within 2 months of CVA or 2 weeks of surgery
Aspiration of clot may improve success rate if the thrombosis is large
Describe surgery in acute limb ischaemia
Both groins should be prepared
Transverse arteriotomy is easier to close
Poor inflow should be managed with iliac trawl- if this fails to improve then consider a femoro-femoral cross over or axillo-femoral cross over.
A check angiogram should be performed on table and prior to closure
Systemic heparinisation should follow surgery
Fasciotomy should be considered if the time between onset and surgery exceeds 6 hours
Indications for amputations
Dead non viable
Deadly where it is posing a major threat to life
Dead useless where it is viable but a prosthesis would be preferable
When is an amputation preferable in Orthopaedic surgery?
Chronic fracture non union or significant limb shortening following trauma
Occasionally following major trauma a primary amputation is preferable.
open fracture with major distal neurovascular compromise and other more life threatening injuries are present
Describe the main types of amputations
Pelvic disarticulation (hindquarter)
Above knee amputation
Gritti Stokes (through knee amputation, patella preserving)
Below knee amputation (using either Skew or Burgess flaps)
Syme’s amputation (through ankle)
Amputations of mid foot and digits
Above knee amputations pros and cons
Quick to perform
Heal reliably
Patients regain their general health quickly
For this benefit, a functional price has to be paid and many patients over the age of 70 will never walk on an above knee prosthesis.
Above knee amputations use equal anterior-posterior flaps
Below knee amputations pros and cons
Technically more challenging to perform
Heal less reliably than their above knee counterparts.
However, many more patients are able to walk using a below knee prosthesis.
In below knee amputations the two main flaps are Skew flaps or the Burgess long posterior flap. Skew flaps result in a less bulky limb that is easier to attach a prosthesis to.
What is a specific contraindication of below knee amputations?
Fixed flexion deformities
Describe the ABPI values and correlations
1.2 or greater - Usually due to vessel calcification
1.0- 1.2 Normal
0.8-1.0 Minor stenotic lesion
Initiate risk factor management
0.50-0.8 Moderate stenotic lesion
Consider duplex
Risk factor management
If mixed ulcers present then avoid tight compression bandages
0.3 - 0.5 Likely significant stenosis
Duplex scanning to delineate lesions needed
Compression bandaging contra indicated
Less than 0.3 Indicative of critical ischaemia
Urgent detailed imaging required
Describe the features of aortic dissection
tear in the intimal layer, followed by formation and propagation of a subintimal hematoma. Cystic medial necrosis (Marfan’s)
Where is the most common site for aortic dissection
90% occurring within 10 centimetres of the aortic valve
How does the location of the dissection correlate to treatment?
A - ascending aorta / root: surgery, aortic root replacement
B - descending aorta: Medical therapy and antihypertensive
Describe the DeBakey classification of aortic dissection
I Ascending aorta, aortic arch, descending aorta
II Ascending aorta only
III Descending aorta distal to left subclavian artery
Clinical features of aortic dissection
Tearing, sudden onset chest pain (painless 10%)
Hypertension or Hypotension
A blood pressure difference (in each arm) greater than 20 mm Hg
Neurologic deficits (20%)
Investigations for aortic dissection
CXR: widened mediastinum, abnormal aortic knob, ring sign, deviation of the trachea/oesophagus
CT angiography of the thoracic aorta
MRI angiography
Conventional angiography (now rarely used diagnostically)
Management of aortic dissection
Beta-blockers: aim HR 60-80 bpm and systolic BP 100-120 mm Hg
For type A dissections the standard of care is aortic root replacement
Causes of axillary vein thrombosis
Primary cause is associated with trauma, thoracic outlet obstruction or repeated effort in a dominant arm (young active individuals)
Secondary causes include central line insertion, malignancy, pacemakers
Clinical features of axillary vein thrombosis
Pain and swelling (non pitting)
Numbness
Discolouration: mottling, dusky
Pulses present
Congested veins
Investigations for axillary vein thrombosis
FBC: viscosity, platelet function
Clotting
Liver function tests
D-dimer
Duplex scan: investigation of choice
CT scan: thoracic outlet obstruction
Treatment of axillary vein thrombosis
Local catheter directed TPA
Heparin
Warfarin
What is the most common head and neck paraganglionoma?
Carotid body tumour
Presentation of carotid body tumours
They typically present as an asymptomatic neck mass in the anterior triangle of the neck. They are typically slow growing lesions
Describe the types of carotid body tumour
Sporadic - Accounts for 85% of cases
Familial - Seen in around 10% of cases and usually in younger patients
Hyperplastic - Seen in those at high altitude or in those with COPD
Imaging for carotid body tumours
They are readily imaged using duplex ultrasonography. CT angiography is sometimes helpful.
Treatment of carotid body tumour
Typically this comprises surgical resection. This is preceded by embolization in selected cases.
Where is the most common site of cervical rib?
Consist of an anomalous fibrous band that often originates from C7 and may arc towards, but rarely reaches the sternum
Clinical features of cervical ribs
Compression of the subclavian artery may produce absent radial pulse on clinical examination and in particular may result in a positive Adsons test (lateral flexion of the neck towards the symptomatic side and traction of the symptomatic arm- leads to obliteration of radial pulse)
