Vascular surgery Flashcards
Causes of acute limb ischemia
Atherosclerosis
Thrombotic: malignancy, infection, shock ( low flow)
Embolic: AF, aneurysm, bacterial endocarditis
Risk factors for peripheral arterial disease
obesity, smoking, diabetes, age, hypercholesterolaemia, hypertension
Symptoms of acute limb ischaemia
Pain
Paresthesia
Paralysis
Pallor
Pulselessness
Perishingly cold
Vascular exam
CVS/PAD orientated
Inspection - comparing both sides, looking for pallor, mottling, skin changes, loss of hair, ulcers, gangrene
Palpate- temperature, pulses
Auscultate - bruit
sensory and motor function of leg
Muscle tenderness
Acute limb ischaemia blood test Ix
FBC, U&E, including a serum lactate (to assess the level of ischaemia), Coag, thrombophilia screen (if <50yrs without known risk factors), Group and Save, Creatine kinase (marker of rhabdomyolysis), elevated CRP
Acute limb iscaemia Ix
ECG
Handheld doppler US to detect both arterial and venous flow on both limbs
CT angiography
ABPI
Classification system for acute limb ischaemia
Rutherford
Acute limb ischaemia Mx
•Oxygen, IV access/ fluids and analgesia
•5000 units of unfractionated heparin
•+/- heparin infusion (if not immediately going to theatre)
Surgical:
endovascular- revascularisation with percutaneous transluminal angioplasty/stenting,Catheter-directed thrombolysis
open- embolectomy, arterial bypass
Amputation if limb not salvageable
Acute limb ischaemia Cx
Compartment syndrome
Release of substances from the damaged muscle cells :
K+ ions causing hyperkalemia
H+ ions causing acidosis
Myoglobin, resulting in significant AKI
Compartment syndrome
Acute increase in pressure within a compartment which endangers the perfusion of tissues, requiring emergency decompression
Compartment syndrome symptoms
Disproportionate ’Crescendo pain’, unresponsive to analgesia
Have high suspicion if after surgery day 3/4 they still need oral morphine and if their ability to do any physio rapidly decreases
Compartment syndrome signs
affected compartment may feel tense
Dorsiflex will tense muscle further and may be too painful for patient to do it will test the ant/post compartment of leg
Eversion/inversion will test the other 2 leg compartments
Causes of compartment syndrome
Reperfusion injury post revascularization in acute limb ischaemia
fractures, crush injuries, burns, rhabdomyolysis
Compartment syndrome Pathophysiology
- Release of free radicals, K+, Ca++, Toxins , cytokines, lactate, leached into local tissue
- it will swell in compartment, increase in intra compartmental pressure
- veins compressed causing fluid to move out into compartment, also venous drainage impaired
- reduced perfusion to area leads to secondary ischaemia episode
- nerves compressed
- ischemia in muscle tissue
Compartment syndrome Ix
clinical dx
If diagnostic uncertainty:
Compartment pressures
pH
A creatine kinase (CK) level
Compartment syndrome Mx
Keep the limb at a neutral level with the patient
High flow oxygen
Augment blood pressure with bolus of IV crystalloid fluids
Remove all dressings / splints / casts, down to the skin
Treat symptomatically with opioid analgesia (usually IV)
Compartment syndrome definitive Mx
Urgent fasciotomy! (double incision to release compartments)
Intermittent claudication
Cramping muscular pain, often in the calf, which is brought on by exertion, relieved by rest and reproducible on walking that distance again.
Critical limb ischemia definition
Ischaemic rest pain >2w despite analgesia or the presence of tissue loss
ABPI <0.5
Critical ischaemia symptoms
Rest pain
Pain is felt in the toes/forefoot as its the most distal
Pain often wakes the patient up at night (loss of gravity’s help in perfusing)
Patients typically hang their legs from the side of the bed
Critical ischaemia signs
limbs may be pale and cold
weak or absent pulses
limb hair loss
skin changes (atrophic skin, ulceration, or gangrene which represents death of tissue)
thickened nails
Buerger’s test
The angle at which the leg becomes pale when you elevate it against gravity
angle of less than 20 degrees indicates severe ischaemia
then swing the patient’s leg over the side and watch out for a “sunset foot”
Ankle-brachial pressure index
measurement of the cuff pressure at which blood flow is detectable by doppler in the posterior tibial or anterior tibial arteries compared to the brachial artery (ankle/brachial pressure)
Mx of chronic limb ischemia
Lifestyle management:
- smoking cessation advice +/- nicotine replacement therapy / further intervention
- Supervised Exercise programmes
- healthy eating,
control of hyperlipidaemia
- weight reduction
- Control of bp
Screen for and Optimise diabetes control
Statin therapy (ideally atorvastatin 80mg OD)
Antiplatelet therapy
Symptomatic relief for IC
Naftidrofuryl oxalate
Peripheral arterial disease differentials
Spinal canal claudication ( but all pulses present)
Spinal cord compression ( calf pain)
Malignancy can cause embolus in acute limb ischemia
Peripheral neuropathy ( associated with numbness and tingling)
Popliteal artery entrapment (young patients who may have normal pulses)
Venous claudication ( bursting pain on walking with previous history of DVT)
Fibromuscular dysplasia
Buerger’s disease