VASCULAR SURGERY Flashcards
What is peripheral arterial disease?
refers to the narrowing of the arteries supplying the limbs and periphery, reducing the blood supply to these areas - usually lower limbs
What is intermittent claudication?
Crampy muscular pain which is brought on by exertion, relieved by rest and reproducible on walking that distance again
It’s due to inadequate oxygen delivery to the muscles
What is is critical limb ischaemia?
Ischaemic rest pain for more than 2 weeks or the presence of tissue loss (ulcers or gangrene)
The far end of the spectrum of chronic limb ischaemia.it often occurs after. A history of intermittent claudication
The limb is at risk
What are the signs of critical limb ischaemia?
The features are pain at rest, non-healing ulcers and gangrene
Pain often wakes pt up at night and hurts the most in the toes/forefoot due to loss of gravity’s help
Pt typically need to hand their legs from the side of the bed or resort to sleeping in chairs
What is acute limb ischaemia?
a sudden decrease in limb perfusion that threatens limb viability. In acute limb ischaemia, decreased perfusion and symptoms and signs develop over less than 2 weeks
What usually causes acute limb ischaemia?
Thrombus blocking arterial supply of distal limb
What is gangrene?
refers to the death of the tissue, specifically due to an inadequate blood supply.
Which arteries does atherosclerosis affect?
Medium and large arteries
What are the consequences of the atheromatous plaques formed in atherosclerosis?
Stiffening of the artery walls, leading to hypertension and strain on the heart whilst trying to pump blood against increased resistance
Stenosis, leading to reduced blood flow
Plaque rupture, resulting in a thrombus that can block a distal vessel and cause ischaemia
What are the non-modifiable risk factors for atherosclerosis?
Older age
FHx
Male
What are the modifiable risk factors for atherosclerosis?
Smoking
Alcohol consumption
Hypertension
Hypercholesterolaemia
Poor diet (high in sugar and trans-fat and low in fruit, vegetables and omega 3s)
Low exercise / sedentary lifestyle
Obesity
Poor sleep
Stress
Which medical comorbidities increase the risk of atherosclerosis?
Diabetes
Hypertension
Chronic kidney disease
Inflammatory conditions such as rheumatoid arthritis
Atypical antipsychotic medications
What are some possible end results of atherosclerosis?
Angina
MI
TIA
Stroke
PAD
Chronic mesenteric ischaemia
Where does pain in intermittent claudication tend to occur?
Calf muscles usually but can also affect the thigh and buttocks
What are the features of critical limb ischameia?
Chronic rest pain, which may be worse at night because of the decrease in blood pressure when asleep and the loss of beneficial gravitational effects on lower limb circulation. People may report sleeping with the leg hanging out of bed, or sleep in a chair to relieve symptoms in the affected foot.
There may sometimes not be a history of intermittent claudication - may not have been clinically apparent in a person with limited mobility/diabetic neuropathy
Dependent rubor, pallor on elevation of the extremity, and reduced capillary refill.
Skin changes including ischaemic ulcers, non-healing foot wounds, and gangrene. Tissue loss usually affects the toes.
Absent foot pulses — however, foot pulses may be palpable in distal embolisation.
What is 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 PAD o/e?
Risk factors - tar staining, xanthomata
CVD - missing limbs/digits after previous amputations, midline sternotomy scare from previous CABG, scar on inner calf for saphenous vein harvesting which may indicate previous CABG, focal weakness may suggest previous stroke
Weak peripheral pulses
Skin pallor
Cyanosis
Dependant rubor
Muscle wasting
Hair loss
Ulcers
Poor wound healing
Gangrene
Reduced skin temp
Reduces sensation
Prolonged cap refill
Changes during Buergers test
What is dependant rubor?
a deep red colour when the limb is lower than the rest of the body
How do you do Buerger’s test?
Buerger’s test is used to assess for peripheral arterial disease in the leg.
There are two parts to the test.
The first part involves the patient lying 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 (rubor)
What are the features of arterial ulcers?
caused by ischaemia secondary to an inadequate blood supply
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
What are the features of venous ulcers?
caused by impaired drainage and pooling of blood in the legs.
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)
How do you investigate PAD?
CV examination
Assess sensory and motor function of legs
Assess for muscle tenderness
Routine bloods - serum lactate to assess the level of ischaemia, Creatine kinase can be a marker of rhabdomyolysis, thrombophilia screen, group and save, FBC, U&E, coag profile, lipid profile, HbA1c
Arterial doppler examination or ABPI/TBPI
ECG - arrhythmia may precipitate an embolic event
Duplex ultrasound
Angiography CT or MRI
Percutaneous transluminal angioplasty - gold standard
What is the ABPI?
the ratio of systolic blood pressure in the ankle compared with the systolic blood pressure in the arm.
Outline how we interpret the results of the ABPI?
<0.5 suggests severe arterial disease.
Refer the person urgently for specialist vascular assessment. Compression treatment is contraindicated
0.5-0.8 suggests the presence of arterial disease or mixed arterial/venous disease. Refer the person for specialist vascular assessment. Compression should generally be avoided
0.8-1.3 suggests no evidence of significant arterial disease. Compression can be safely applied
>1.3 may suggest the presence of arterial calcification, such as in some people with diabetes, rheumatoid arthritis, systemic vasculitis, atherosclerotic disease, and advanced chronic renal failure. For values above 1.5, the vessels are likely to be incompressible, and the result cannot be relied on to guide clinical decisions.
What does an ABPI >1.3 indicate?
can indicate calcification of arteries, making them diffiuclt to compress
More common in diabetic patients
How do you manage intermittent claudication?
Lifestyle changes e.g. stop smoking and high protein/low fat and carb diet
Optimise treatment of comorbidities
Supervised exercise programme
Secondary prevention - Atorvastatin 80mg and Clopidogrel 75mg OD
Naftidrofuryl oxalate
Surgical options
What are the surgical options for PAD?
Endovascular angioplasty and stenting
Endarterectomy
Bypass surgery
What does Endovascular angioplasty and stenting involve?
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.
What does an endarterectomy involve?
The surgeon makes a small incision along the blocked or narrowed artery and physically removes the plaque.
What does an bypass surgery involve?
surgeons create an alternative conduit for blood flow to circumvent the area of blockage and restore direct flow to the lower leg and foot. This is done using your own saphenous vein or an artificial vein
How do you manage critical limb ischaemia?
Urgent referral to vascular team
Analgesia (paracetemol -> opioids)
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
How is acute limb ischaemia managed?
Arrange emergency assessment by a vascular specialist
ABC approach
Analgesia
IV 5000 units ofunfractionated heparin to prevent thrombus propagation
Definitive management - endovascular or surgical interventions
What does endovascular thrombolysis involve?
inserting a catheter through the arterial system to apply thrombolysis directly into the clot
What does endovascular thrombectomy involve?
Inserting a catheter through the arterial system and removing the thrombus by aspiration or mechanical devices
What does surgical thrombectomy involve?
cutting open the vessel and removing the thrombus
What usually causes peripheral arterial disease? What are other causes?
Atherosclerosis
Less common:
Inflammatory disorders e.g. vasculitis
Non-inflammatory arteriopathies e.g. fibromuscular dysplasia
Chronic limb threatening ischaemia can also be caused by:
Thromboembolism
Buerger’s disease
Trauma
Dissection
Physiological entrapment syndromes
Cystic adventitial disease
What causes acute limb ischaemia?
Most commonly Embolisation - may be from AF, post-MI, mural-thrombus, AAA or prosthetic heart valves
Thrombus - atheroma plaque rupture
Trauma, dissection, compartment syndrome - less common
What proportion of people >60 have some degree of PAD/
20%
What are the complications of PAD/
Impairment of quality of life by claudication and limitation of mobility
Psychosocial consequences e.g. depression
Ulceration and gangrene
Risk of amputation
Procedural complications
Higher risk of vascular complications e.g. MI, stroke, vascular dementia, mesenteric disease, Reno vascular disease
What are complications of acute limb ischaemia?
Compartment syndrome
Reperfusion injury
What is compartment syndrome?
An acute increase in pressure within a compartment which endangers the perfusion of tissues, requiring emergency decompression
What is reperfusion injury?
the damage that occurs after blood supply is restored to a tissue or organ after a period of ischemia.
products of cell death (for example potassium, phosphate and myoglobin) are released when blood flow to the ischaemic limb is restored. This can result in rhabdomyolysis, cardiac dysrhythmia, AKI, multiorgan failure, and DIC.
How do we differentiate between ischaemia caused by embolus vs caused by thrombus?
Embolus - onset is acute <24 hours, limb appears white because there is no collateral circulation and vascular examination in other leg is usually normal, no history of claudicatipn, clinically obvious source of embolus e.g. AF
Thrombosis - onset is more gradual, leg may not be white and symptoms less severe due to collateral circulation. Presentation is usually with worsening claudication and rest pain. Pulses in other leg may also be absent. Evidence of widespread vascular disease e.g. MI, stokes
Why is the pain in critical limb ischaemia worse at night?
because of the decrease in blood pressure when asleep and the loss of beneficial gravitational effects on lower limb circulation
How do you assess cardiovascular risk?
QRISK assessment tool
How should you manage people with a CVD risk of <10%?
Lifestyle - stop smoking, weight loss if overweight, healthy eating, alcohol consumption in recommended limits, physically active
Optimise management of comorbidities - - AF, CKD, DM, dyslipidaemia, hypertension, obesity, periodontitis, RA, SLE, serious mental health problems
How should you manage people with a CVD risk of >10%?
Lifestyle advice
Optimise management of comorbidities
Atorvastatin 20mg daily
Antihypertensive
What are the differential diagnoses for PAD?
Neurogenic claudication - pain typically starts in the buttock and radiates down the leg
PVD - pain starts in calf and typically radiates up the leg
What is neurogenic claudication?
Intermittent leg pain from impingement of the nerves emanating from the spinal cord
results from compression of the spinal nerves in the lumbar spine
The most common symptoms of lumbar spinal stenosis
What is a percutaneous transluminal angioplasty?
A balloon is used to widen the artery, which in some cases, may be enough on its own. In many cases, a stent is also placed.
Only good for short lesions <5cm
What are the stages of atherosclerosis?
Endothelial dysfunction
Formation of fatty streak in tunica intima
Migration of leukocytes and smooth msucle cells into vessel wall
Foam cell formation
Degradation of extracellular matrix
What are the 3 main presentations of peripheral arterial disease?
intermittent claudication
critical limb ischaemia
acute limb-threatening ischaemia
Whats the typical presenting complaint for rest pain and why?
burning pain in the ball of the foot and toes that is worse at night when the patient is in bed.
The pain is exacerbated by the recumbent position because of the loss of gravity-assisted flow to the foot.
How does chronic limb ischaemia present?
as intermittent claudication or critical limb ischaemia i.e. circulation is so severely impaired that there is an imminent risk of limb loss
How soon would complete arterial occlusion lead to irreversible tissue damage?
<6 hours
What are the typical features of acute limb ischaemia?
Pain
Pulselessness
Pallor
Paralysis
Paraesthesia
Perishing with cold
What do the supervised exercise programmes for intermittent claudication involve?
two hours of supervised exercise a week for a 3-month period and encouraging people to exercise to the point of maximal pain
why should people exercise to maximal pain with intermittent claudication
It is thought that exercise can encourage the development of collateral circulation, causing smaller arteries to enlarge, allowing them to carry more blood, and therefore more oxygen to the muscles.
Whats the moa of naftidrofuryl oxalate?
Blocks 5-HT2 receptors and causes vasodilation
What dose of naftidrofuryl oxalate should be given for PVD?
100-200mg 3 times a day
What monitoring should be done for naftidrofuryl oxalate?
It should be assessed for improvement after 3-6 months and LFTs should be checked as it can cause liver toxicity
If all ok it should be continued for life
How is CVD prevented in PVD?
Clopidogrel 75mg daily
Atorvastatin 80mg daily
Both of these for life
Outline the classification tool used for acute limb ischaemia?
Rutherford
Category 1 - no immediate threat.
Category 2a - inaudible arterial dopler and minimal sensory loss e.g. just toes - salvageable if promptly treated
Category 2b - sensory loss, rest pain, mild/moderate motor deficits, inaudible arterial Doppler - salve a gable only if immediately revascularised
Category 3 - profound sensory loss, paralysis, inaudible arterial and venous Doppler - irreversible
What are the options for definitive management of acute limb ischaemia?
Endovascular therapies, for example:
Percutaneous catheter-directed thrombolytic therapy.
Percutaneous mechanical thrombus extraction.
Surgical interventions, for example:
Surgical thromboembolectomy.
Endarterectomy.
Bypass surgery.
Amputation if the limb is unsalvageable.
What are anterograde and retrograde angiograms?
Antegrade is used when the vascular sheath is oriented in the same direction as blood flow. Retrograde indicates that the sheath is pointed in the opposite direction of the blood flow within the vessel.
What are the pros and cons of anterograde and retrograde angiogram approach?
Anterograde - better wire control with short wire, short distance to lesion
Retrograde allows you to view both legs
What can increase your risk of Coronary artery calcification ?
CKD
Diabetes
Advanced age
Rheumatoid arthritis
Systemic vasculitis
Atherosclerotic disease
What is TBPI?
Toe brachial pressure index
a noninvasive way of determining arterial perfusion in feet and toes. Used when the ABPI is abnormally high due to plaque and calcification of the arteries in the leg
How do you interpret TBPI readings?
> 0.7 normal
0.64-0.7 borderline
<0.64 is abnormal and suggests arterial disease
What are the pros and cons of duplex ultrasound for investigating PAD?
Pros - quick, done as outpatients or at bedside, non-invasive, no radiation, no contrast, cheap, easy to use, accessible
Cons - operator dependant, may not be able to look at iliac blood vessels or crural blood vessels
What are the pros and cons of CT angiogram for investigating PAD?
Pros - often available, 3D image, head-to-toe image, good for aneurysms, good for large blood vessels
Cons - radiation, contrast, not good for soft tissue imaging, picks up a lot of calcification which causes artefacts
What are the pros and cons of CT MRI for investigating PAD?
Pros - detailed, good for soft tissue, good for all sized vessels
Cons - contrast, bad for aneurysms, diffiuclt to get hands on, expensive, takes a long time, may be tricky for pt as they have to lie flat for at least 20 minutes, can cause renal fibrosis in CKD patients (although newer contrasts are much safer), can’t be used on pt with pace makers or metal work
What are the pros and cons of percutaneous transluminal angiography for investigating PAD?
Pros - stents and angioplasties can be performed at the same time, good for any vessel size, can treat any pathology
Cons - contrast, risks damage to vessels as very invasive, operant dependant,m expensive, specialist so needs trained radiographer and specific X-ray
When is a carbon dioxide angiography indicated?
high-risk states for iodinated contrast-induced nephropathy and iodinated contrast allergy
What was the BASIL-2 study?
Bypass vs Angioplasty in Severe Ischaemia of the Leg - an ongoing study
It suggested that bypass surgery should be the choice if the pt is expected to live >2years and has a suitable saphenous vein to harvest
What is a major amputation?
Any amputation be formed proximal to the ankle or wrist
What are primary, secondary and traumatic amputations?
Primary - amputation performed without an attempt at limb salvage
Secondary - amputation following a failed attempt at revasculiarsation
Traumatic - limb loss that occurs in the field at the time of injury
What is a hemicorporectomy?
a radical surgery in which the body below the waist is amputated, transecting the lumbar spine. This removes the legs, the genitalia (internal and external), urinary system, pelvic bones, anus, and rectum
What is a hemipelvectomy/ Hindquarter amputation?
a surgical procedure that involves the removal of portion of the pelvic girdle as well as the amputation of the whole leg on the affected side
What is a Hip Disarticulation?
amputation of the lower limb through the hip joint
What is a transfemoral amputation?
Above the knee amputation
What is Knee Disarticulation?
Amputation through the knee joint
What is a transtibial amputation?
Amputation below the knee
What is an ankle Disarticulation?
Amputation through the ankle joint
What is Syme’s amputation?
Amputation at the level of the ankle joint and the foot is removed but the heel pad is saved so the pt can put weight on the leg - designed to minimize disability and preserve function
What is residual limb pain caused by?
Very likely post operative pain
Peripheral nerve neuroma formation at the end of cut peripheral nerve
Prosthetic pain caused by ill fitting prosthesis
What is phantom limb pain?
pain that is localized in the region of the removed body part.
Cause of Phantom limb pain is not fully understood , but it is distressing and has a significant impact on patients life.
Whats the epidemiology of acute limb ischaemia?
1 in 12,000 per year
What are the symptoms of compartment syndrome?
Disproportionate ‘crescendo pain’ which is unresponsive to analgesia
Paraesthesia may occur
Pulselesssness and paralysis may occur later on
Whats the aetiology of compartment syndrome?
Repurfusion injury post revasculairsation in acute limb ischaemia
Other causes - fractures, crash injuries, burns
How do you investigate compartment syndrome?
Clinical diagnosis
The most reliable diagnostic test is siting an intra-compartmental pressure monitor - normal compartmental pressures are 0-8mm Hg
A creatine kinase level may aid diagnosis, if elevated
How do you manage compartment syndrome?
Keep the limb at a neutral level with the patient
Improve oxygen delivery with high flow oxygen
Augment blood pressure with bolus of intravenous crystalloid fluids- this transiently improves perfusion of the affected limb
Remove all dressings / splints / casts, down to the skin
Treat symptomatically with opioid analgesia
FASCIOTOMY
the skin incisions are then left open and a re-look is planned for 24-48 hours. This is to assess for any dead tissue that needs to be debrided.
If the remaining tissues are healthy, the wounds can then be closed
What monitoring needs to be done after compartment syndrome has occurred?
Monitor renal function closely, due to the potential effects of rhabdomyolysis or reperfusion injury.
Outline the pathophysiology of atherosclerosis?
Endothelial dysfunction (allows LDL in)
High amounts of circulating LDLs -> deposit in tunica intima and become oxidised due to ROS from dysfunctional endothelium
Oxidised LDL activate endothelial cells causing them to express receptors for WBC
Adhesion of WBC to activated endothelial cells allows monocytes and T helper cells to move into the tunica intima. Monocytes become macrophages when in tissues
Macrophages engulf oxidised LDL and become foam cells
Foam cells promote migration of smooth muscle cells from tunica media into tunica intima. And promotes smooth muscle cell proliferation. This proliferation causes synthesis of collagen = hardening of plaque
Foam cells die and release lipid content = drives growth of plaque
As plaque grows it increases in pressure which can lead to rupture
Whats the reason for the vast majority of lower limb amputations carried out in the UK?
PAD with or without diabetes