Vascular 3 Flashcards
What is the thoracic outlet?
Space between the first rib and clavicle, through which the subclavian artery, subclavian vein and brachial plexus pass
What is thoracic outlet syndrome?
Narrowing of the thoracic outlet causing neurological or arterial symptoms
What are the causes of thoracic outlet syndrome?
Cervical rib
Healed clavicular fracture
Excess muscle development
What is the presentation of thoracic outlet syndrome?
Neurological deficits in the T1 distribution - wasting of teh small muscles of the hand, paraesthesia of the inner forearm and hand
Arterial symptoms - upper limb claudication: if working with hands above head
post-stenotic dilatation (aneurysm) which can thrombus to cause acute arterial occlusion
What examinations / investigation findings of thoracic outlet syndrome are there?
Arm BP will be lower in the affected arm and vary with posture
Arteriography can confirm obstruction, and plain XR will show a cervical rib or healed clavicular fracture
What is the management of thoracic outlet syndrome?
often surgical, with excision of the cervical rib and often the first rib with any obstructing fibrous bands
Post-stenotic subclavian aneurysm will also need grafting
How many venous systems are there in the lower limb?
2: superficial and deep venous system
What is the deep system made of? what does it do?
A number of veins that accompany the major arteries of the lower limb and drain the muscular compartment
What is the superficial system made of?
Superficial: medial long (great) saphenous vein which drains to the saphenofemoral junction and the laterally placed short saphenous vein which drains into the popliteal vein
What is the function of the superficial system?
Drains the skin and superficial tissues
Where are the two systems joined?
at the saphenofemoral and saphenopopilteal junctions
What are the perforating veins?
Additional communications between the two systems
What is the function of valves in the leg veins?
Prevent backflow of blood
Are there valves in the vena cava / common iliac veins?
What is the effect of this?
Central pool of blood in the trunk
What is venous return to the heart driven by?
Pressure from the muscular pumps below, and inspiration decreasing intrathoracic pressure
As the calf muscles contract, the deep veins are squeezed and emptied, to force blood upwards
As the muscle relaxes, blood from the superficial system will flow into the deep veins via the perforators, which will again be squeezed upwards as the calf muscles contract once more
What does venous disease in the deep veins lead to?
Deep venous insufficiency
What does venous disease in the superficial veins lead to?
Simple varicose veins
What is the cause of venous disease in either the superficial / deep venous system?
Valvular incompetence
What are varicose veins?
dilated, tortuous, superficial veins that occur secondary to incompetent venous valves, allowing blood to flow back, away from the heart. They most commonly occur in the legs due to reflux in the great saphenous vein and small saphenous vein
Which is more common, primary or secondary varicose veins?
Who gets them?
Primary
twice as common in women, with pregnancy accentuating symptoms
Likely to be due to a primary superficial valve defect, with familial elements
(no deep venous incompetence)
What is the cause of secondary varicose veins?
Superficial varicosities occurring secondary to deep venous incompetence:
Previous DVT: although occluded veins recanalise, their valves remain incompetent
Raised systemic venous pressure: due to compression (pelvic tumour, pregnancy), artery-venous fistula or severe tricuspid incompetence
What are the symptoms of varicose veins?
Cosmetic
tiredness, aching or throbbing of the legs
Oedema of the ankles, particularly on standing for long periods
Itching and nocturnal cramps are reported
signs of deep venous insufficiency: haemosiderosis, eczema, lipodermatosclerosis
When does deep venous insufficiency occur?
When the valves of the deep venous system are incompetent
Calf can no longer efficiently return blood to the thoracic cavity
can be primary or secondary
What is the primary cause of deep venous insufficiency?
Secondary?
primary: congenital absence of the valves
Secondary: DVT causing valvular damage or AVF raising venous pressure
What are the features of deep venous insufficiency?
Lower limb aching pain/discomfort
oedema of the lower leg
superficial varicose veins - raised central pressure causes perforator incompetence
Haemosiderin deposition in the gaiter area
eczema - particularly over the pigmented area, causing pruritus
Atrophie blanche
Lipodermatosclerosis: subcutaneous fissure replaced by thick fibrous tissue, giving an inverted champagne bottle appearance
Ulceration
How is deep venous insufficiency confirmed?
Duplex sonography or venography to confirm diagnosis of deep venous insufficiency
What is the management of deep venous insufficiency?
No successful way to repair / replace the deep valves of the venous system
How is venous disease investigated?
Hand held doppler: can identify reflux @ saphenofemoral / saphenopopliteal junctions
Duplex scanning: can diagnose valvular and perforating vein incompetence, as well as large vein occlusion
venography: torniquet placed around the ankle to occlude superficial veins and contrast then injected into the foot
Fluoroscopy then used to see the progress through the deep system, with deep vein occlusion and perforating vein reflux readily detected
What is the Trendelenberg test?
no longer a recognised method of diagnosis:
elevate the leg to 45 degrees to empty the superficial veins (assist manually)
Tourniquet applied distal to saphenofemoral junction
Patient asked to stand and if there is isolated saphenofemoral reflux, then the varicosities will take >15 seconds to refill from the arterial circulation
Test then repeated with the tourniquet taken off immediately on standing and if the varicosities fill immediately, this suggests there is reflux at this level
the test is repeated moving the tourniquet further down the leg, to find the lowest point of deep to superficial incompetence
What are the indications for treatment of varicose veins?
significant/troublesome lower limb symptoms e.g. pain, discomfort or swelling
previous bleeding from varicose veins
skin changes secondary to chronic venous insufficiency (e.g. pigmentation and eczema)
superficial thrombophlebitis
an active or healed venous leg ulcer
What are the management options for varicose veins?
Lifestyle advice: avoid prolonged standing, exercise regularly and lose weight
Graded compression stockings: for minor varicosities, the elderly / unfit and for pregnancy
endothermal ablation: using either radiofrequency ablation or endovenous laser treatment
foam sclerotherapy: irritant foam → inflammatory response → closure of the vein
surgery: either ligation or stripping
How is endothermal ablation done?
often the treatment of choice, with a laser fibre passed along the vein (USS guided) and then fired to cause heat and endothelial ablation, causing the vein to thrombose
What is the purpose of sclerotherapy? how is it done?
For cosmetically undesirable superficial varicosities
Chemical sclerosant is injected into an empty vein, and the vein is kept compressed with bandaging for two weeks to allow fibrosis to take place
USS guided foam sclerotherapy is becoming more commonly used
What is the surgical procedure for varicose veins?
Disconnecting the great saphenous vein from the femoral vein (+/- ‘stripping’ of the vein)
Any incompetent perforators are individually ligated
What complications can arise from untreated varicosities?
Haemorrhage: caused by minor trauma to a dilated vein
superficial thrombophlebitis: can occur spontaneously or following sclerotherapy
Veins become hard (thrombosis) and tender, with overlying erythema
there may be systemic upset
What is the location of DVT?
Occur in the deep veins of the leg - originating around the valves
Most common veins to thrombose are the anterior tibial, posterior tibial, perineal, superficial femoral or popliteal vein
What are the risk factors for venous thrombosis?
Often occurs in normal vessels, thus stasis and hypercoagulability factors = main risk factors:
age/immobility
pregnancy/OCP
Malignancy
Obesity
Surgery (typically occur in week 2 post-surgery)
Previous DVT
What are the clinical features of DVT?
Calf tenderness and firmness
Oedema
Erythema and Calor
Distention of superficial veins
Superficial thrombophlebitis (tender, erythematous, palpable superficial vein)
Homan’s sign (pain on dorsiflexion of the ankle, however this is unreliable and should not be tested for as it may dislodge the thrombus)
What are the atypical presentations of DVT?
Ilio-femoral thrombosis can present with severe pain but few physical signs
Complete occlusion of a large vein can lead to cyanotic discolouration
What is the presentation of PE?
Sudden onset unexplained dyspnoea
pleuritic chest pain
haemoptysis
What investigations should be done for DVT?
2 level Wells score
If likely: proximal leg USS
If +ve: treatment
if -ve: D dimer
If unlikely:
D-dimer - if this is high then do proximal leg USS
What are the complications of DVT?
Deep venous insufficiency
How should post-surgical DVT be managed?
Stop COCP 4 weeks pre-op
Mobilise as early as possible
Immobile patients should be heparinised (6 hours post surgery)
At right patients: stockings/intermittent pneumatic pressure (until 16 hours post-op)
How is DVT treated?
Analgesia.
Treatment dose NOAC: apixaban or rivaroxaban
Continue anticoagulation for:
3 months if provoked
6 months if not provoked
How can DVT be excluded?
If pre-test probability is low, do D-dimer to exclude
If D-dimer positive or pre-test probability is moderate or high, perform compression USS to confirm DVT
PERC to rule out
What is the Well’s score?
Calculated to gage pre-test probability of DVT
Scores based on variety of clinical features
What is the cause of pulmonary emboli?
Generally caused by DVTs in the leg
What is the presentation of pulmonary emboli?
Sudden onset breathlessness, pleuritic pain and haemoptysis, however should be included in almost any respiratory differential as they are common and variable in presentation
Lead to increased pulmonary artery pressure (right heart strain) and ischaemia of the lung, with a ventilation / perfusion mismatch
Often occur around day 10 post-surgically
What are the three types of PE?
Massive PE
Major PE
Minor PE
What is a MASSIVE PE?
(5% PEs)
>60% of the pulmonary circulation is blocked, leading to rapid cardiovascular collapse
thrombolysis is now recommended as the first-line treatment for massive PE where there is circulatory failure (e.g. hypotension)
What is a MAJOR PE?
(10% PEs)
Middle sized pulmonary arteries are blocked, leading to breathlessness, pleuritic chest pain and haemoptysis
What is a MINOR PE?
(85% PEs)
small peripheral vessels are blocked, and patients may be asymptomatic or present as above (haemoptysis rare)
Massive PE may ensue following a minor PE, which is known as the ‘premonitory embolus’
What are the signs of PE?
Evidence of a DVT
Raised JVP
Cyanosis if the embolus is large
What investigations should be done for a PE?
FBC, U+E, clotting, D-dimer
ABG: T1RF
CXR: often normal, or dilated pulmonary artery, wedge shaped opacities
ECG: SINUS TACHYCARDIA RBBB, RV strain S1QIIITIII rare LARGE S wave in Lead 1 Q wave in lead 3 T wave inversion in lead III
Echo: can confirm right heart strain
CTPA: gold standard
V/Q if this is unavailable, but less accurate if pre-existing lung disease (use in renal impairment)
What is the management of PE?
Major/minor PE (same as DVT)
Apixaban or rivaroxaban first line (march 2020)
LMWH if not suitable
The options for long term anticoagulation in VTE are warfarin, a NOAC or LMWH.
The target INR for warfarin is 2-3. When switching to warfarin continue LMWH for 5 days or the INR is 2-3 for 24 hours on warfarin (whichever is longer).
What is the management of MASSIVE PE?
A-E
IV morphine and anti-emetic
thrombolysis is now recommended as the first-line treatment for massive PE where there is circulatory failure (e.g. hypotension)
If SPB >90 - warfarin
If <90mmHg - start vasopressors (noradrenaline) before commencing thrombolytic therapy
What is lymphedema?
Swelling which results from an increased quantity of fluid in the interstitial space of soft tissues, due to failure of lymphatic drainage
Causes chronic non-pitting oedema, commonly affecting the legs and progressing with age
What is primary lymphedema?
Primary - presents in early life and is a result of an inherited deficiency of lymphatic vessels (Milroy’s disease)
What is secondary lymphedema?
due to obstruction of lymphatic vessels
e.g. Filaria infection - repeated cellulitis, malignancy, post operative
How is lymphoscintography used for lymphedema?
Used to confirm diagnosis, after other causes of oedema have been excluded (CCF, renal disease, deep venous insufficiency_
What is the management of lymphedema?
Elevation, compression stockings and physical massage, with long term antibiotics for recurrent cellulitis (each episode further damages lymphatic drainage)
What is the purpose of duplex USS?
gives anatomical and physiological (flow) information non-invasively, but requires an experienced operator
What is the purpose of angiography?
Used when invasive procedures are planned, with contrast injected by a series of catheters most commonly introduced at the femoral artery
Fluoroscopy is then used to visualise the arterial system
What are the risks of angiography?
Contrast reaction, haematoma, pseudoaneurysm, AVF formation or arterial occlusion
How are CTA/MRA used for evaluation of the arterial system?
CTA: used more for carotid/cerebral disease
MRA used to assess thoracic, abdominal or limb disease
