Chapter 100 Acute limb ischemia evaluation and decision making Flashcards
Causes of acute limb ischemia
1) Trauma 2) Iatrogenic 3) Arterial embolism 4) Thrombosis
Origin of the word embolism
Greek: “plug”
Define saddle emboli
At aortic bifurcation
Most common location of emboli in lower extremity
1) CFA 2) Popliteal
Most common location of emboli in upper extremity
1) brachial bifurcation 2) brachial artery at take off of profunda brachialis
Characteristic of secondary thrombus
Plum colored and obstructs distal small vessels
Causes of emboli
1) Cardiac (atrial or ventricular) 2) Paradoxical from DVT via foramen ovale 3) Bacterial endocarditis 4) Cardiac tumor (atrial myxoma)
Classic patient with paradoxical emboli
young patient with DVT and concurrent acute ischemia
Cases of cardiac thrombus
1) Afib 2) Mural thrombus secondary to MI 3) Valve disease
Non-cardiac embolism
1) Atheroembolism from vessel itself 2) aortic mural thrombus
Atheroembolism types
1) Platelet rich thrombus 2) Atheromatous plaque (hard to remove)
Causes of atheroembolism
1) Spontaneous 2) iatrogenic
Aortic mural thrombus characteristics
1) Absence of aortic pathology 2) hypercoagulable state 3) normal cardiac exam
Causes of acute thrombosis
1) Atheroclerotic obstruction 2) Hypercoagulable state 3) Vasospasm 4) Aortic dissection 5) Bypass graft occlusion
Treatment of acute vasospasm (secondary raynauds)
1) Anticoagulation to prevent secondary thrombosis 2) tpa 3) vasodilator 4) prostanoid
Clinical presentation stages of acute limb ischemia
1) Sensory nerve loss 2) muscle nerve loss (weakness) 3) skin ischemia (vasodilation blanchable to capillary disruption non-blanchable) 4) Muscle death = tender and rigor
Changing demographic pattern of acute limb
used to be more valve now afib older patients with more chronic disease
Time to irreversible necrosis
6-8 hours
6 P’s of acute limb ischemia
Pallor Pain Pulselessness Paralysis Parasthesia Polar
Transatlantic Inter-society Consensus 2007 definition of ALI
Sudden decrease in limb perfusion causing threat to viability
Classification of acute limb ischemia
Management consideration for aortoiliac occlusion (acute)
Needs urgent surgery
High risk to renal injury either
1) primary insult
2) due to reperfusion
Water-hammer pulse
Most common at CFA due to distal CFA embolism/thrombosis
Imaging modalities in acute limb ischemia
U/S
CTA
Angio
Considerations around Echo in acute limb ischemia
Debated usefulness given no change in management
Use it in young patient where cardiac diagnosis suspected and may change management regarding life long anticoagulation
Initial treatment in acute limb ischemia
1) anticoagulation to treat secondary thrombosis
2) O2 to give increase skin perfusion
3) IVF to hydrate and to prevent contrast-induced nephropathy
4) Analgesia: avoid intramuscular injection due to TPA bleed
Usefulness of anticoagulation alone in treating acute limb ischemia
Ok in Class I and Class III
Stabilizes clot and prevents further secondary thrombosis
History of balloon embolectomy
1963 Fogarty
Management options of Class IIb
1) Surgery
2) percutaneous endovascular thrombetomy
3) accelerated tpa
Management of Class IIa
1) Surgery
2) tpa +/- mechanical thrombectomy
Prognosis following acute limb ischemia
Poor especially in setting of cancer; life expectancy 6 months
Indication to perform surgery urgently in acute limb ischemia without needing additional information
1) Class IIb
2) obvious embolic source
3) pulse in contralateral leg
Causes of upper extremity limb ischemia
1) Cardiac embolism
2) TOS
3) proximal subclavian aneurysm
Indication to treat upper extremity acute limb ischemia
1) prevent future fatigue with use
2) prevent pain (50% of patients)
3) prevent contracture/amputation in future
Mortality with acute upper extremity ischemia
20% mortality from index event
5 year survival 60%
Age of upper extremity ischemia pateints compared to lower
4 years older for upper extremity
