Acute Limb Ischemia (ALI) is any sudden onset of ischemia, or worsening of pre-existing chronic limb ischemia (acute on chronic limb ischemia) limiting blood flow to the limb, which potentially endangers the viability of the limb

It is a life-threatening disease that needs to be treated in specialized centers

It manifests as pain, sensory and motor deficit of the limb, followed by general symptoms and without therapy it ends with the death of the patient

2.1 Pathophysiology of ALI

• atherosclerosis with thrombosis

• arterial embolism

• cystic degeneration of the arterial media

• aneurysm of the popliteal artery

• arterial entrapment syndrome

• trauma (subadventitial rupture, iatrogenic injury ...)

• closure of vascular reconstruction

2.2 Etiology of ALI - the most common models

Thrombotic occlusions: in elderly patients with pre-existing atherosclerotic lesions. Most often in the area of ​​the superficial femoral artery. Claudications can usually be found in the patient’s history

Embolic occlusions: sudden occlusion of an artery in a patient who usually had no symptoms of arterial ischemia in the past, there are often palpable pulsations of peripheral arteries of the contralateral limb

2.3 Diagnostics of ALI

Clinical examination: rule 6P (Pain, Paleness, Pulselessness, Paresthesias, Paralysis, Prostration)

Imaging methods: sonography, CT angiography

Img. 4 Acute limb ischemia

Source: Authors‘ archive

2.4 Rutherford’s classification of ALI

Img. 5 Rutherford ALI

Adapted from Cronenwett, Jack L. and Johnston, K. Wayne, "Rutherford's Vascular Surgery, 2-Volume Set (8th ed.)" (2014).

Recommended procedure: stage IIa and IIb - immediate surgery, stage III - amputation (irreversible ischemia, risk of multi-organ failure and death of the patient, high values of CK (creatine kinase), myoglobin etc.)

2.5 Initial management of patients with ALI:

anticoagulation – intravenous heparin administration as soon as possible, unless contraindicated (prevention of further growth of thrombosis)

oxygen therapy    

analgetics

fluid therapy

imaging methods (optionally for the upper limbs) and consultation with a specialized vascular center

2.6 Further treatment of ALI:

a) surgery

- embolectomy, thrombectomy (Fogarty's catheter), thromboembolectomy in case of growing thrombus above the embolic occlusion, endarterectomy, bypass, intraoperative isolated limb thrombolysis

b) endovascular intervention

- thrombolysis (rtPA Alteplase) and PTA

- mechanical aspiration thrombectomy

c) in rare cases conservative treatment, anticoagulation, vasodilators ...

d) in case of irreversible limb ischemia (severe extensive advanced ischemia in a polymorbid patient) - primary amputation

2.7 Compartment syndrome

- most often in patients with long-lasting acute ischemia of tissues (over 6 hours), manifestation after successful revascularization (but also after trauma with hematoma to soft tissues etc.), causes significantly increased tissue pressure in the muscle compartment (most often shin muscles, above 30 – 40 mmHg), thereby limiting microcirculation, clinical finding of stiffness at the muscle group, symptomatology: muscle group pain, movement impaired, sensoric defect, preserved peripheral pulsations. Peripheral edema leads to hemoconcentration and hypovolemia. Lung, kidney and heart problems are possible.

therapy: decompression fasciotomy - especially on the lower leg, temporary covering of the wound with prosthetic material, or negative pressure wound therapy. After the swelling subsides resuture or partial suture and subsequent covering of the residual wound with a dermo-epidermal grafts

2.8 Related diagnosis: Crush Syndrome

- flushing of mediators of inflammation, toxic metabolites and oxygen radicals from ischemic cells + damage to endothelial cell membranes, i.e. systemic effect in reperfusion syndrome - hyperkalemia with risk of malignant arrhythmia, acidosis, myoglobinemia, endothelial disorder with increased permeability to the interstitium incl. pulmonary hypertension, increased pulmonary hypertension, toxic effects on the myocardium, arrhythmias, acute renal failure due to myoglobin deposits in the renal tubules

Diagnosis: oligo-anuria, brown-red color of urine (myoglobinuria), hypovolemia with hypotension, tachycardia, tachypnoea, ECG changes, increase in creatine-kinase (CK), myoglobin level, hyperkalemia, acidosis with decrease in pH and increase in lactate

Therapy: in some cases conservatively - limb elevation, cold compresses, anti-edematous therapy (Mannitol etc.), but in all other cases fasciotomy, forced diuresis - several liters of crystalloids per day, support of diuresis by intravenous furosemide, or even renal function replacement (does not affect myoglobin) - rather continuous methods

Img. 6 Fasciotomy

Source: Authors‘ archive

2.9 Prognosis of a patient with acute limb ischemia:

Patients with ALI up to 1 year:

survival with both limbs – 50 %

limb amputation – 25 %

mortality from cardiovascular causes – 25 %