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)
Treatment of cervical ribs
Treatment is most commonly undertaken when there is evidence of neurovascular compromise. A transaxillary approach is the traditional operative method for excision.
What causes varices
Varices occur because of localised weakness in the vein wall resulting in dilatation and reflux of blood due to non union of valve cusps.
Describe the histology of chronic venous insufficiency
Histologically, the typical changes include fibrous scar tissue dividing smooth muscle within media in the vessel wall.
What causes tissue damage in chronic venous insufficiency
Tissue damage in chronic venous insufficiency occurs because of perivascular cytokine leakage resulting in localised tissue damage coupled with impaired lymphatic flow
Describe symptoms of chronic venous insufficiency
Dependant leg pain
Prominent leg swelling
Oedema extending beyond the ankle
Venous stasis ulcers
Describe the two tests used in chronic venous insufficiency
Brodie-Trendelenburg test: to assess level of incompetence
Perthes’ walking test: assess if deep venous system competent
Describe the investigations used in chronic venous insufficiency
Doppler exam: if incompetent a biphasic signal due to retrograde flow is detected
Duplex scanning: to ensure patent deep venous system (do if DVT or trauma)
What must be done for ALL patients prior to treatment in chronic venous insufficiency?
Doppler assessment to assess for venous reflux and should be classified as having uncomplicated varicose veins or varicose veins with associated chronic venous insufficiency.
Duplex scan on day of surgery for patients with saphenopopliteal incompetence
Indications for Treatment of chronic venous insufficiency
Cosmetic: majority
Lipodermatosclerosis causing venous ulceration
Recurrent superficial thrombophlebitis
Bleeding from ruptured varix
Treatment of Symptomatic uncomplicated varicose veins
endothermal ablation,
foam sclerotherapy,
saphenofemoral / popliteal disconnection,
stripping and avulsions,
compression stockings
Treatment of varicose veins with skin changes
endothermal ablation,
foam sclerotherapy,
saphenofemoral / popliteal disconnection,
stripping and avulsions,
compression stockings
Treatment of Chronic venous insufficiency or ulcers
Class 2-3 compression stockings (ensure no arterial disease).
Describe the trendelenburg procedure
Head tilt 15 degrees and legs abducted
Oblique incision 1cm medial from artery
Tributaries ligated (Superficial circumflex iliac vein, Superficial inferior epigastric vein, Superficial and deep external pudendal vein)
SF junction double ligated
Saphenous vein stripped to level of knee/upper calf. NB increased risk of saphenous neuralgia if stripped more distally
Most common causes of acyanotic congenital heart disease
Ventricular septal defects (VSD) - most common, accounts for 30%
Atrial septal defect (ASD)
Patent ductus arteriosus (PDA)
Coarctation of the aorta
Aortic valve stenosis
Causes of cyanotic congenital heart disease
Tetralogy of Fallot
Transposition of the great arteries (TGA)
Tricuspid atresia
Pulmonary valve stenosis
Describe KT syndrome
Klippel-Trenaunay-Weber syndrome generally affects a single extremity, although cases of multiple affected limbs have been reported. The leg is the most common site followed by the arms, the trunk, and rarely the head and the neck
Describe the signs and symptoms of KT syndrome
One or more distinctive port-wine stains with sharp borders
Varicose veins
Hypertrophy of bony and soft tissues, that may lead to local gigantism or shrinking.
An improperly developed lymphatic system
What can KT syndrome affect?
KTS can either affect blood vessels, lymph vessels, or both. The condition most commonly presents with a mixture of the two. Those with venous involvement experience increased pain and complications
What causes ulcers to form in venous leg ulcers?
capillary fibrin cuff or leucocyte sequestration
Investigations of venous ulcers
Doppler ultrasounds to look for presence of reflux and duplex ultrasound
Management of venous ulcers
4 layer compression banding after exclusion of arterial disease or surgery
What is a Marjolin’s ulcer?
Squamous cell carcinoma
Occurring at sites of chronic inflammation e.g; burns, osteomyelitis after 10-20 years
Mainly occur on the lower limb
Describe arterial ulcers
Occur on the toes and heel
Painful
There may be areas of gangrene
Cold with no palpable pulses
Low ABPI measurements
Describe neuropathic ulcers
Commonly over plantar surface of metatarsal head and plantar surface of hallux
The plantar neuropathic ulcer is the condition that most commonly leads to amputation in diabetic patients
Due to pressure
Management includes cushioned shoes to reduce callus formation
Describe pyoderma gangrenosum
Associated with inflammatory bowel disease/RA
Can occur at stoma sites
Erythematous nodules or pustules which ulcerate
Causes of primary lymphoedema
Congenital < 1 year: sporadic, Milroy’s disease
Onset 1-35 years: sporadic, Meige’s disease
> 35 years: Tarda
Causes of secondary lymphoma
Bacterial/fungal/parasitic infection (filariasis)
Lymphatic malignancy
Radiotherapy to lymph nodes
Surgical resection of lymph nodes
DVT
Thrombophlebitis
Indications for surgery in lymphoedema
Marked disability or deformity from limb swelling
Lymphoedema caused by proximal lymphatic obstruction with patent distal lymphatics suitable for a lymphatic drainage procedure
Lymphocutaneous fistulae and megalymphatics
Describe the Homans operation for lymphoedema
Reduction procedure with preservation of overlying skin (which must be in good condition). Skin flaps are raised and the underlying tissue excised. Limb circumference typically reduced by a third
Describe the Charles operation for lymphoedema
All skin and subcutaneous tissue around the calf are excised down to the deep fascia. Split skin grafts are placed over the site. May be performed if overlying skin is not in good condition. Larger reduction in size than with Homans procedur
Describe lymphovenous anastomosis for lymphoedema
Identifiable lymphatics are anastomosed to sub dermal venules. Usually indicated in 2% of patients with proximal lymphatic obstruction and normal distal lymphatics.
What are the indications fo surgery to revascularise the lower limb?
Intermittent claudication
Critical ischaemia
Ulceration
Gangrene
Describe an angioplasty
In order for angioplasty to be undertaken successfully the artery has to be accessible. The lesion relatively short and reasonable distal vessel runoff. Longer lesions may be amenable to sub-intimal angioplasty.
Describe the procedure of bypass surgery
Artery dissected out, IV heparin 3,000 units given and then the vessels are cross clamped
Longitudinal arteriotomy
Graft cut to size and tunneled to arteriotomy sites
Anastomosis to femoral artery usually with 5/0 ‘double ended’ Prolene suture
Distal anastomosis usually using 6/0 ‘double ended’ Prolene
Describe bypass in distal disease
Femoro-distal bypass surgery takes longer to perform, is more technically challenging and has higher failure rates.
In elderly diabetic patients with poor runoff a primary amputation may well be a safer and more effective option. There is no point in embarking on this type of surgery in patients who are wheelchair bound.
In femorodistal bypasses vein gives superior outcomes to PTFE.
What are the ‘rules’ of bypass surgery
Vein mapping 1st to see whether there is suitable vein (the preferred conduit). Sub intimal hyperplasia occurs early when PTFE is used for the distal anastomosis and will lead to early graft occlusion and failure.
Essential operative procedure as for above knee fem-pop.
If there is insufficient vein for the entire conduit then vein can be attached to the end of the PTFE graft and then used for the distal anastomosis. This type of ‘vein boot’ is technically referred to as a Miller Cuff and is associated with better patency rates than PTFE alone.
What are the 4 characteristic features of Tetralogy of Fallot?
ventricular septal defect (VSD)
right ventricular hypertrophy
right ventricular outflow tract obstruction, pulmonary stenosis
overriding aorta
Describe the management in ToF
surgical repair is often undertaken in two parts
cyanotic episodes may be helped by beta-blockers to reduce infundibular spasm
What are some other features of ToF
cyanosis
causes a right-to-left shunt
ejection systolic murmur due to pulmonary stenosis (the VSD doesn’t usually cause a murmur)
a right-sided aortic arch is seen in 25% of patients
chest x-ray shows a ‘boot-shaped’ heart, ECG shows right ventricular hypertrophy
Describe axillary / brachial emboli
50% of upper limb emboli will lodge in the brachial artery
30% of upper limb emboli will lodge in the axillary artery
Sudden onset of symptoms; pain, pallor, paresis, pulselessness, paraesthesia
Sources are left atrium with cardiac arrhythmia (mainly AF), mural thrombus
Cardiac arrhythmias may result in impaired consciousness in addition to the embolus
Describe arterial occlusions
Those resulting from atheroma are the most common, trauma may result in vascular changes and long term occlusion but this is rare
Features may include claudication, ulceration and gangrene. Proximally sited lesions may result in subclavian steal syndrome
The progressive nature of the disease allows development of collaterals, acute ischaemia may occur as a result of acute thrombosis
Treatment of Raynaud’s disease
Calcium antagonists
What is a venous doppler?
The simplest investigation for assessment of venous junctional incompetence is a Doppler assessment. This involves the patient standing and manual compression of the limb distal to the junction of interest. Flow should normally occur in one direction only. Where junctional incompetence is present reverse flow will occur and is relatively easy to identify.
What are venograms and duplex scans
Structural venous information is historically obtained using a venogram. This is an invasive test and rarely required in modern clinical practice. The most helpful test is a venous duplex scan which will provide information relating to flow and vessel characteristics. Duplex is also useful in providing vein maps for bypass surgery.
What is an arterial duplex
As with the vein the duplex scan can provide a substantial amount of information about arterial patency and flow patterns. In skilled hands they can provide insight as to the state of proximal vessels that are anatomically inaccessible to duplex (e.g. Iliacs). Through assessment of distal flow patterns. It is an operator dependent test.
What is a conventional angiogram?
Vessel puncture and catheter angiography is the gold standard method of assessing arteries
This technique is particularly useful in providing a distal arterial roadmap prior to femoro-distal bypass.
Describe CT angiography
These tests provide a considerable amount of structural and flow information. They require contrast
They are particularly useful in the setting of GI bleeding
