This topic is under the category of Arterial Diseases. It is very important for an MBBS students to know about ALI, so as to treat them initially and then refer them to vascuar surgeons.

1. Prof. U. Murali.
Acute
Limb Ischemia

2. Learning Objectives
◼ Outline the causes, pathophysiology & features of ALI.
◼ Classify the severity of acute limb ischemia.
◼ Differentiate between Embolism & Thrombosis.
◼ Mention the sources, effects and features of arterial embolism.
◼ Enumerate the investigative methods of ALI.
◼ Describe the treatment of embolism & thrombosis of ALI.

3. A L I – Introduction
◼ It is a sudden decrease in limb
perfusion that threatens limb
viability {within 2 weeks}.
◼ ALI is an emergency that requires
rapid, accurate clinical
assessment and emergency
surgical treatment.
◼ ALI typically occurs because of
embolic arterial occlusion (or)
trauma.
◼ It is common in lower limb, upper
limb; but can occur in mesenteric,
cerebral, coronary arteries.

4. A L I – Causes
◼ Embolism is the most common cause in
developing country.
◼ Trauma.
◼ Thrombosis of an artery: Normal artery can
develop sudden acute thrombosis in certain
special situations with hypercoagulable
status like malignancy, leukemia,
antiphospholipid antibody syndrome,
protein C / protein S / antithrombin
deficiency; polycythemia rubra vera,
thrombocytosis. It is commonly observed in
external iliac artery, profunda femoris artery
and popliteal artery.
◼ Thrombosis of a bypass graft is common
cause in western countries which occurs at
the site of anastomosis.

5. A L I – Pathophysiology
◼ Distal ischemia begins immediately
after acute obstruction.
◼ Most sensitive peripheral nerves are
first involved, and then muscles,
subcutaneous tissue and skin are
affected in order.
◼ Irreversible ischemia occurs in 6 hours.
Golden period is 1-6 hours.
◼ Ischemia may get aggravated by -
propagation of thrombus below and
above the block occluding the orifices
of collaterals, fragmentation of
embolus, associated thrombosis, ACS.

6. A L I – Presentation – 7 ‘P’ s…
◼ Pain – which is continuous, severe,
steady, bursting.
◼ Pallor – of the distal part with extreme cold
limb.
◼ Pulselessness – sudden loss of earlier
palpable pulse.
◼ Paresthesia – sensory disturbances like
tingling, numbness (or) complete loss of
sensation.
◼ Paresis – damage to motor nerve and
muscle leading into paralysis as a late
grave feature. [poor prognostic sign]
◼ Poikilothermia – change in the
temperature (cold).
◼ Purplish mottling – Fixed staining of skin.
◼ Pain – skin & muscle ischemia.
◼ Pallor – no blood supply, so looks pale.
◼ Pulselessness – no arterial input.
◼ Paresthesia – Due to nerve ischemia.
◼ Paralysis – Due to muscle ischemia.
◼ Perishing cold – Poikilothermia - Due
to lack of blood warming the limb.
◼ Mottled - First, non-fixed (blanching to
pressure) and then fixed (non-
blanching), indicating skin death.

8. 8
Acute Limb Ischemia
Differences between embolism and thrombosis
Features Embolism Thrombosis
Onset Seconds / minutes Hours / days
Source Present Not present
Symptoms More severe Less severe
Previous
history
H/O - Source H/O – Chronic
ischemia
Severity &
Collaterals
Complete ischemia
No collaterals
Incomplete –
Well developed
Pulse Proximal &
contralateral pulses
- normal
Ipsilateral and
opposite side
pulses may be
absent
Temperature Severely cold Cold (or) normal
Angiography Sharp cut off sign Diffuse &
tapered
Treatment Embolectomy -
Warfarin
Medical / Bypass
Thrombolysis

9. Embolism
◼ ‘Embolus’ means in Greek—peg; first this term was
used by Virchow in 1854.
◼ It is due to a solid, liquid (or) gaseous, material
which is floating and travelling in the bloodstream,
eventually blocking the vessel on its pathway.

10. SOURCES TYPES
◼ Cardiac (80%)
◼ Non-cardiac (10%)
◼ Idiopathic (10%)
◼ Others (4%)
◼ Cryptogenic (5%)
◼ Arterial Emboli
◼ Venous Emboli
◼ Venous-arterial Emboli
◼ Fat Emboli
◼ Air Emboli

11. SITES - LODGING EFFECTS
◼ Lower limb (75%)
 Common femoral artery
(40%)
 Popliteal artery (15%)
 Common iliac artery (12%)
 Aortic bifurcation (10%)
◼ Brain (10%)
◼ Upper limb (10%)
◼ SMA & RA (5%)

12. Embolism – C/F
◼ H/O - claudication is absent but history
suggestive of disease for source of
emboli will be present.
◼ Sudden, dramatic, rapid development of
pain with numbness.
◼ Limb becomes rapidly cold and mottled
with blebs & oedema - distally & Loss of
sensation and movements.
◼ Absence of distal pulses but forcible,
expansile, prominent proximal pulse.
◼ Muscle which is soft normally while
palpating will feel doughy initially but
later becomes stiff.

13. A L I - Investigations
◼ ECG / ECHO – Source of emboli.
◼ Duplex scan – To assess arterial tree.
◼ Angiogram [DSA] – Status of vessel
proximally & distally. [Gold standard]
◼ Creatinine kinase.
◼ RFT / Lipid profile.
◼ Coagulation profile.
◼ Routine Basic tests.

14. ALI - Treatment – Embolism
◼ Immediate infusion of
5000 units [80u/kg –
bolus | 18u/kg/hr] of I.V.
heparin and relief of
pain (opioids) are
needed first.
◼ Surgical – Embolectomy
Interventional methods
 Closed - Using
Fogarty’s catheter.
 Open - Arteriotomy –
direct approach.

15. ALI - Treatment – Thrombosis
◼ Immediate infusion of 5000
units [80u/kg – bolus |
18u/kg/hr] of I.V. heparin and
relief of pain (opioids) are
needed first.
◼ Intra-arterial thrombolysis –
• Urokinase – commonly used.
• Streptokinase.
• TPA – Alteplase / Reteplase.
◼ Thrombectomy [PMT] –
• Via catheter – suction.
• Dissolution – aspiration.
◼ Bypass surgery – Last resort –
failed other procedures.

18. Complications of Revascularization - A L I
◼ Reperfusion injury
 Hyperkalemia
 Myoglobinuria
 Lactic acidosis
 Renal failure
◼ Acute Compartment Syndrome
◼ Sepsis
◼ Bleeding
◼ Re-block

21. To Summarize
◼ Causes & Pathophysiology of ALI.
◼ Clinical features of ALI.
◼ Rutherford classification of ALI [severity].
◼ Sources and types of emboli.
◼ Effects of emboli on various organs.
◼ Difference between emboli & thrombosis.
◼ Investigations and Treatment methods of acute limb ischemia.

22. References

23. ◼
Thank You

24. Question Time
◼ Write the pathophysiology of ALI.
◼ Classify ALI.
◼ List 5 differences between embolism & thrombosis.
◼ Mention the reasons for the clinical features of ALI.
◼ Enumerate the investigative methods of ALI.
◼ Outline the treatment methods of embolism causing ALI.
◼ Define embolism. Identify the source and types of emboli.
◼ Tabulate the advantages & disadvantages of thrombolysis.

25. Which of the following is the most common
source of thrombus emboli? –
◼ a) Cardiac arrhythmias.
◼ b) Arterial aneurysms.
◼ c) Thrombi from atheromatous plaques.
◼ d) Deep vein thrombosis.

26. All of the following are true statements
regarding intra-arterial thrombolysis, except –
◼ a) Intra-arterial thrombolysis is suitable for less severe ischemia.
◼ b) A Fogarty catheter is used.
◼ c) TPA is preferred to streptokinase.
◼ d) Thrombolytic therapy is contraindicated in pregnancy.

27. Patient with acute embolism of lower extremity
should undergo embolectomy within ____ hrs.
of onset –
◼ a) 2 – 4.
◼ b) Within 4.
◼ c) 6 – 8.
◼ d) 24 – 48.
◼

28. One of the following is true regarding acute
limb ischemia –
◼ a) Aspirin is the drug of choice.
◼ b) Emergency embolectomy is limb saving.
◼ c) Mottling is an early sign.
◼ d) Embolectomy is common in patients with sinus rhythm.

29. A patient presents with sudden bluish discoloration of
the toe. Which of the following will be the next
appropriate investigation in this patient? –
◼ a) C T angiogram.
◼ b) M R angiogram.
◼ c) Digital subtraction angiography.
◼ d) Duplex scan.

33. ◼
Thank You