Vascular Surgery Flashcards
What is PAD?
Peripheral arterial disease (PAD) refers to the narrowing of the arteries supplying the limbs and periphery, reducing the blood supply to these areas.
What is the main symptom seen with PAD?
claudication
What are the different types of ischaemia?
Intermittent claudication
Critical limb ischaemia
Acute limb ischaemia
What is ischaemia
refers to an inadequate oxygen supply to the tissues due to reduced blood supply.
WHat is necrosis?
refers to the death of tissue.
WHat is gangrene?
Gangrene refers to the death of the tissue, specifically due to an inadequate blood supply.
WHat is Intermittent claudication
is a symptom of ischaemia in a limb, occurring during exertion and relieved by rest. It is typically a crampy, achy pain in the calf, thigh or buttock muscles associated with muscle fatigue when walking beyond a certain intensity.
What si critcial ischaemia?
s the end-stage of peripheral arterial disease, where there is an inadequate supply of blood to a limb to allow it to function normally at rest
There is a significant risk of losing the limb.
How does critcial limb ischaemia present as?
The features are pain at rest, non-healing ulcers and gangrene.
What is acute limb ischaemia?
refers to a rapid onset of ischaemia in a limb. Typically, this is due to a thrombus (clot) blocking the arterial supply of a distal limb, similar to a thrombus blocking a coronary artery in myocardial infarction.
Cause of PAD
Atherosclerosis
WHat is Atherosclerosis
WHich arteries does it affect
Atherosclerosis is a combination of atheromas (fatty deposits in the artery walls) and sclerosis (the process of hardening or stiffening of the blood vessel walls).
Atherosclerosis affects the medium and large arteries. It is caused by chronic inflammation and activation of the immune system in the artery wall.
Lipids are deposited in the artery wall, followed by the development of fibrous atheromatous plaques.
Non modifiable risk factors for Atherosclerosis
Older age
Fhx
Male
Modifiable risk factors for Atherosclerosis
- Smoking
- Alcohol consumption
- Poor diet (high in sugar and trans-fat and low in fruit, vegetables and omega 3s)
- Low exercise / sedentary lifestyle
- Obesity
- Poor sleep
- Stress
Medical Co-Morbidities for atherosclerosis
Diabetes
Hypertension
Chronic kidney disease
Inflammatory conditions such as rheumatoid arthritis
Atypical antipsychotic medications
What are the End Results of Atherosclerosis
- Angina
- Myocardial infarction
- Transient ischaemic attack
- Stroke
- Peripheral arterial disease
- Chronic mesenteric ischaemia
What are the features of Critical Limb Ischaemia
6Ps
Pain
Pallor
Pulseless
Paralysis
Paraesthesia (abnormal sensation or “pins and needles”)
Perishing cold
causes burning pain, worse at night when the leg is raised, as gravity no longer helps pull blood into the foot.
WHat is Leriche Syndrome
Name the clinical traid?
Leriche syndrome occurs with occlusion in the distal aorta or proximal common iliac artery. There is a clinical triad of:
- Thigh/buttock claudication
- Absent femoral pulses
- Male impotence
What are the signs of arterial disease on general inspection ?
- Skin pallor
- Cyanosis
- Dependent rubor (a deep red colour when the limb is lower than the rest of the body)
- Muscle wasting
- Hair loss
- Ulcers
- Poor wound healing
- Gangrene (breakdown of skin and a dark red/black change in colouration)
- Missing limbs or digits after previous amputations
- Midline sternotomy scar (previous CABG)
- A scar on the inner calf for saphenous vein harvesting (previous CABG)
- Focal weakness suggestive of a previous stroke
On examination aterial disease would show?
- Tar staining on the fingers
- Xanthomata (yellow cholesterol deposits on the skin)
- Reduced skin temperature
- Reduce sensation
- Prolonged capillary refill time (more than 2 seconds)
- Changes during Buerger’s test
What disease does Buerger’s Test test for
peripheral arterial disease in the leg.
Explain how to perform a Buerger’s test?
The first part involves the patient lying on their back (supine). Lift the patient’s legs to an angle of 45 degrees at the hip. Hold them there for 1-2 minutes, looking for pallor. Pallor indicates the arterial supply is not adequate to overcome gravity, suggesting peripheral arterial disease. Buerger’s angle refers to the angle at which the leg is pale due to inadequate blood supply. For example, a Buerger’s angle of 30 degrees means that the legs go pale when lifted to 30 degrees.
The second part involves sitting the patient up with their legs hanging over the side of the bed. Blood will flow back into the legs assisted by gravity. In a healthy patient, the legs will remain a normal pink colour. In a patient with peripheral arterial disease, they will go:
- Blue initially, as the ischaemic tissue deoxygenates the blood
- Dark red after a short time, due to vasodilation in response to the waste products of anaerobic respiration
The dark red colour is referred to as rubor
What is the difference between aterial ulcers and venous ulcers on definition
Arterial ulcers are caused by ischaemia secondary to an inadequate blood supply
Venous ulcers are caused by impaired drainage and pooling of blood in the legs.
What are the features of arterial ulcers?
- Are smaller than venous ulcers
- Are deeper than venous ulcers
- Have well defined borders
- Have a “punched-out” appearance
- Occur peripherally (e.g., on the toes)
- Have reduced bleeding
- Are painful
- Are pale colour due to poor blood supply
- Have pain worse at night (when lying horizontally
- Have pain is worse on elevating and improved by lowering the leg (gravity helps the circulation)
WHat are the features of Venous ulcers
- Occur after a minor injury to the leg
- Are larger than arterial ulcers
- Are more superficial than arterial ulcers
- Have irregular, gently sloping borders
- Affect the gaiter area of the leg (from the mid-calf down to the ankle)
- Are less painful than arterial ulcers
- Occur with other signs of chronic venous insufficiency (e.g., haemosiderin staining and venous eczema)
- Have pain relieved by elevation and worse on lowering the leg
What can you use to accurately assess the pulses when they are difficult to palpate.
hand-held Doppler
Ix for PAD?
- Ankle-brachial pressure index (ABPI)
- Duplex ultrasound – ultrasound that shows the speed and volume of blood flow
- Angiography (CT or MRI) – using contrast to highlight the arterial circulation
What is an Ankle-Brachial Pressure Index
Ankle-brachial pressure index (ABPI) is the ratio of systolic blood pressure (SBP) in the ankle (around the lower calf) compared with the systolic blood pressure in the arm.
What do you use to measure Ankle-Brachial Pressure Index
Doppler probe
How do you calculate Ankle-Brachial Pressure Index
Divide the highest ankle systolic pressure in each of the posterior tibial and dorsalis pedis arteries* in both feet by the highest brachial systolic pressure from each arm; the lowest resulting value is the patient’s overall ABPI.
For example, an ankle SBP of 80 and an arm SBP of 100 gives a ratio of 0.8 (80/100).
What do the ratio from ABPI indicate
- 9 – 1.3 is normal
- 6 – 0.9 indicates mild peripheral arterial disease
- 3 – 0.6 indicates moderate to severe peripheral arterial disease
Less than 0.3 indicates severe disease to critical ischaemic
An ABPI above 1.3 can indicate calcification of the arteries, making them difficult to compress. This is more common in diabetic patients
Management of Intermittent Claudication are usually lifestyle changes and exercise training
Medication can also be used as treatment
What medication can be given?
- Atorvastatin 80mg
- Clopidogrel 75mg once daily (aspirin if clopidogrel is unsuitable)
- Naftidrofuryl oxalate (5-HT2 receptor antagonist that acts as a peripheral vasodilator)
What are some surgical options for management for intermittent claudication?
- Endovascular angioplasty and stenting
- Endarterectomy – cutting the vessel open and removing the atheromatous plaque
- Bypass surgery – using a graft to bypass the blockage
Endovascular angioplasty and stenting involve inserting a catheter through the arterial system under x-ray guidance. At the site of the stenosis, a balloon is inflated to create space in the lumen. A stent is inserted to keep the artery open. Endovascular treatments have lower risks but might not be suitable for more extensive disease.
Management of Critical Limb Ischaemia
Patients with critical limb ischaemia require urgent referral to the vascular team. They require analgesia to manage the pain.
Urgent revascularisation can be achieved by:
- Endovascular angioplasty and stenting
- Endarterectomy
- Bypass surgery
- Amputation of the limb if it is not possible to restore the blood supply
Management of Acute Limb Ischaemia
Patients with acute limb ischaemia need an urgent referral to the on-call vascular team for assessment.
Management options include:
- Endovascular thrombolysis – inserting a catheter through the arterial system to apply thrombolysis directly into the clot
- Endovascular thrombectomy – inserting a catheter through the arterial system and removing the thrombus by aspiration or mechanical devices
- Surgical thrombectomy – cutting open the vessel and removing the thrombus
- Endarterectomy
- Bypass surgery
- Amputation of the limb if it is not possible to restore the blood supply
What is VTE
Venous thromboembolism (VTE) is a common and potentially fatal condition. It involves blood clots (thrombi) developing in the circulation. This usually occurs secondary to stagnation of blood and hyper-coagulable states
How does something like atrual septal defect cause a person to have a stroke if they have a DVT
If the patient has a hole in their heart (for example, an atrial septal defect), the blood clot can pass through to the left side of the heart and into the systemic circulation. If it travels to the brain, it can cause a large stroke.
Risk Factors for DVT or PE
- Immobility
- Recent surgery
- Long haul travel
- Pregnancy
- Hormone therapy with oestrogen (combined oral contraceptive pill and hormone replacement therapy)
- Malignancy
- Polycythaemia
- Systemic lupus erythematosus
- Thrombophilia
TOM TIP: In your exams, when a patient presents with possible features of a DVT or PE, ask about risk factors such as periods of immobility, surgery and long haul flights to score extra points.
What is Thrombophilias
Name examples?
Thrombophilias are conditions that predispose patients to develop blood clots. There are a large number of these:
- Antiphospholipid syndrome
- Factor V Leiden
- Antithrombin deficiency
- Protein C or S deficiency
- Hyperhomocysteinaemia
- Prothombin gene variant
- Activated protein C resistance
OM TIP: If you remember one cause of recurrent venous thromboembolism, remember antiphospholipid syndrome. The common association you may come across in exams is recurrent miscarriage. The diagnosis can be made with a blood test for antiphospholipid antibodies.
What does Prophylaxis consist of for risk of VTE
Every patient admitted to hospital should be assessed for their risk of venous thromboembolism (VTE). If they are at increased risk of VTE, they should receive prophylaxis unless contraindicated.
Prophylaxis is usually with low molecular weight heparin, such as enoxaparin. Contraindications include active bleeding or existing anticoagulation with warfarin or a DOAC.
Anti-embolic compression stockings are also used, unless contraindicated. The main contraindication for compression stockings is significant peripheral arterial disease
Presentation of DVT
DVTs are almost always unilateral. DVTs can present with:
- Calf or leg swelling
- Dilated superficial veins
- Tenderness to the calf (particularly over the site of the deep veins)
- Oedema
- Colour changes to the leg
Bilateral DVT is rare and bilateral symptoms are more likely due to an alternative diagnosis such as
chronic venous insufficiency or heart failure.
To examine for leg swelling, measure the circumference of the calf 10cm below the tibial tuberosity. More than _cm difference between calves is significant.
3
Diagnosis of DVT
D-dimer
Doppler ultrasound of the leg is required to diagnose deep vein thrombosis. NICE recommends repeating negative ultrasound scans after 6-8 days if a positive D-dimer and the Wells score suggest a DVT is likely.
CTPA
Pulmonary embolism can be diagnosed with
CT pulmonary angiogram (CTPA) or ventilation-perfusion (VQ) scan.
CTPA is usually preferred, unless the patient has significant kidney impairment or a contrast allergy.
What other conditions can raise a D-Dimer
Pneumonia
Malignancy
Heart failure
Surgery
Pregnancy
Initial Management for DVT or PE?
anticoagulation: apixaban or rivaroxaban
consider catheter-directed thrombolysis in patients with a symptomatic iliofemoral DVT
WHat are the options for Long Term Anticoagulation DVT/PE patients
The options for long term anticoagulation in VTE are a DOAC, warfarin, or LMWH.
What are DOACs
DOACs are oral anticoagulants that do not require monitoring. They were called “novel oral anticoagulants” (NOACs), but this has been changed to “direct-acting oral anticoagulants” (DOACs)
They are suitable for most patients, including patients with cancer.
