acute arterial ischemia and vascular trauma Flashcards
what is acute limb ischaemia ?
a sudden decrease in limb perfusion
what does the effect of sudden arterial occlusion depend on ?
size of the blood vessel occluded and the state of the collateral blood flow
what is the aetiology of acute limb ischaemia ?
acute embolic ischaemia
acute thrombotic ischaemia
acute traumatic ischaemia
where are we more likely to find an acute embolus causing ischaemia ?
at arterial bifurcation
whether aortic, iliac , femoral or popliteal
what is the difference between embolic and thrombotic ischaemia ?
with embolic ischaemia a relatively healthy artery is affected whereas thrombotic there is already an underlying pathology
what are the consequences of having an embolus in each of these organs ?
brain
retina
mesenteric vessels
brain - TIA or stroke
Retina- Amaurosis fugax or permanent blindness
mesenteric vessels- intestinal angina or intestinal gangrene
when is claudication pain present ?
claudication pain is only present with thrombosis
what are the risk factors for acute embolic occlusions ?
atrial fibrillation
recent AMI
prosthetic heart valves
what are the risk factors for acute thrombotic occlusions ?
no specific risk factors but the blood vessels are diseases (underlying pathology)
what is the clinical presentation for acute limb ischaemia ?
pain paralysis pulseless perishingly cold pallor paraesthesia
in terms of colour changes what are the differences in late and early stages of acute limb ischaemia ?
early –> pale in colour
late –> cyanosed then mottling then fixed mottling and cyanosis
what does the loss of motor function indicates ?
indicates advanced limb threatening ischaemia
what is an indication of late irreversible ischaemia ?
muscle turgidity
which muscles are first affected with acute limb ischaemia ?
intrinsic foot muscles followed by the leg muscles
why is it difficult to detect early muscle weakness ?
because toe movements are produced mainly by leg muscles
what does poikilothermic mean ?
when the limb acquires the temperature of the surroundings due to the lack of perfusion
what is the staging of acute limb ischaemia ?
I: Viable
IIA: Marginally threatened
IIB: immediately threatened
III: Irreversible
in which stage of acute arterial ischaemia would there be rest pain ?
stage IIB where the limb is immediately threatened
what kind of investigations would you carry out ?
doppler/duplex ( duplex not so much routine)
angiography ( CTA/MRA) –> CTA is the first line
digital subtraction angiography
which imaging modality would be avoided with patients with limited renal function ?
avoid CTA , perform MRA
what are the goals of therapy with acute ischaemia ?
prevention of propagation
restoration of blood flow
preservation of the limb
prevention of recurrence
what is the immediate management with ALI ?
give the patient IV heparin and analgesia
what would the management options acordingto the stagging of the ritheford clasaification ?
stage I- imaging
Stage IIa- imaging
stage IIb - imaging if no delay
stage III- amputation
what are the methods of revascularization ?
thromboelectomy
catheter directed thrombolysis
endovascular techniques
bypass surgery
what are some simple measure that can be taken to improve existing perfusion ?
keep the foot dependent avoid pressure over the heel avoid extremes of temperature maximize tissue oxygenation correct hypotension start treatment of any other associated conditions
how would we intervene in a case of embolic occlusion ?
embolectomy using a Fogarty catheter , an arrteriotomy through the common femoral artery ( balloon and catheter)
how would you intervene in the case of an acute thrombotic occlusion ?
first perform an arteriogram then for intervention:
a long segment occlusion - surgical bypass
short segment occlusion - thrombolytic therapy then we can perform either balloon angioplasty or vascular bypass
what intervention could be performed with traumatic vascular disease ?
end to end anastomosis with autologous vein graft
what are the possible complications following intervention?
- reperfusion syndrome
- recompartment syndrome
- catheter related
what are the complications of reperfusion injury ?
myocardial injury remote lung injury renal injury gastrointntestinal compartment syndrome
what is the treatment for compartment syndrome ?
urgent fasciotomy to release the compression
what are the mechanisms of vascular trauma ?
blunt
penetrating
iatrogenic
what are the hard signs?
absent or diminished distal pulses active haemorrhages expanding hematoma bruit distal ischaemia
what are the soft signs ?
small, stable hematoma injury to anatomically related nerve unexplained hypotension Hx of haemorrhages proximity of injury to major vessel
what are the myocardial depressant factors ?
C3a TxA2 LTD4
when is the best time of management ?
within the first 6 hours
what is the gold standard of investigation ?
Angiography
what are the different sources of embolism ?
cardiac sources - left atrium in atrial fib, mural thrombus in MI, endocarditis, valvular disease
arterial sources - aneurysm, atherosclerotic plaque, aneurysm
paradoxical
what are the sources off thrombosis ?
atherosclerosis
vascular graft
thrombosis of an aneurysm
entrapment syndrome
hypercoaguable state
low flow state
what manoeuvre is completely contraindicated in acute limb ischemia ?
raising the leg
