Acute Limb Ischemia Flashcards
What condition is marked by a sudden decrease in limb perfusion that threatens the viability of the limb, often caused by embolism or thrombosis.
Acute Limb Ischemia (ALI)
What are the main etiologies of acute limb ischemia (ALI)?
- Thrombosis (e.g., at the site of atherosclerosis or aneurysm),
- Embolism,
- Phlegmasia (extensive venous backup, very rare),
- Trauma.
What are the six Ps of acute limb ischemia?
Pain, Pallor, Pulselessness, Poikilothermia (coldness), Paresthesia, and Paralysis.
What is the most common cause of embolism leading to ALI?
Cardiac sources such as atrial fibrillation, left ventricular thrombus, or endocarditis (septic emboli).
What are the typical physical exam findings in acute limb ischemia?
Coolness to touch, delayed or absent capillary refill, absent arterial pulses, and sensory or motor deficits in severe cases.
How is acute limb ischemia classified based on limb viability?
- Viable limb: No tissue loss, normal capillary refill, audible Doppler signals.
- Threatened limb: Delayed capillary refill, partial sensory or motor deficits, inaudible arterial Doppler signals.
- Nonviable limb: Absent capillary refill, complete sensory and motor loss, irreversible tissue damage.
How is acute limb ischemia classified by severity and intervention?
- Viable (Class I): Mild pain, intact capillary refill and pulses, no intervention needed.
- Marginally threatened (Class IIa): Moderate pain, diminished pulses, possible sensory deficits, requires urgent revascularization.
- Immediately threatened (Class IIb): Severe pain, sensory/motor deficits, absent pulses, requires emergent revascularization.
- Irreversible ischemia (Class III): Complete paralysis/no sensation, signs of dead tissue, requires amputation.
What is the first-line treatment for a threatened limb in acute limb ischemia?
Emergency surgical revascularization.
Why is emergency surgical revascularization required in ALI even for patients with heart failure?
ALI can cause irreversible tissue damage (myonecrosis) within 4-6 hours if untreated, making immediate surgery essential regardless of comorbid conditions.
What is the initial medical management for suspected ALI?
Intravenous heparin infusion to prevent thrombus propagation.
When is catheter-directed thrombolysis appropriate in ALI?
For patients with a viable limb (audible Doppler signals, no sensory or motor deficits), typically caused by extensive thrombosis rather than embolism.
What diagnostic tests are used for acute limb ischemia?
Doppler ultrasound to assess arterial and venous flow; in some cases, CT angiography or MR angiography to evaluate the site of occlusion.
What are risk factors for acute limb ischemia?
Atrial fibrillation, recent myocardial infarction, heart failure, peripheral artery disease, hypercoagulable states, vascular trauma, patients with a history of coronary artery disease with a previous anterior wall myocardial infarction, heart failure with reduced ejection fraction, hypertension, and hyperlipidemia.
What is the role of transthoracic echocardiography (TTE) in ALI?
TTE can be used after stabilization to evaluate for cardiac sources of embolism, such as left ventricular thrombus or valvular disease.
What are the potential complications of untreated ALI?
Irreversible myonecrosis, limb amputation, metabolic acidosis, hyperkalemia, rhabdomyolysis, and death.
