Acute limb ischemia is a vascular emergency defined as a sudden interruption of blood supply to a limb, threatening limb viability. It is commonly caused by arterial embolism or thrombosis. The degree of obstruction, site of occlusion, and presence of collateral circulation determine the pathophysiology. Tissues tolerate ischemia at different rates, with nerves being first affected and skin last. Diagnosis involves imaging studies and blood tests. Treatment depends on whether ischemia is reversible or irreversible, with anticoagulation, endovascular intervention, open surgery, or amputation used depending on the situation. Factors like delay in treatment and underlying conditions impact outcomes.

1. ACUTE LIMB ISCHAEMIA
Dr Kunwar Sidharth Saurabh
Resident, Mch CTVS
VMMC & SJH

2. Introduction
• Defined as 
– Sudden interruption of blood supply to limb
resulting in threat to the limb viability.
• One of the most common vascular
emergencies
• Incidence will only increase as the population
ages and cardiac care improves

3. Etiology
• Arterial Embolism
• Thrombosis
• Traumatic
• Acute Aortic Dissection
• Rare Causes – low flow states (cardiogenic
shock, sepsis etc) , Drugs (cocaine,
vasopressors), Vasculitis.

5. SVS GRADE ACUTE LIMB ISCHAEMIA

6. Embolism vs Thrombosis
Embolism Thrombosis
Sudden onset pain Sub acute onset
Young patient Elderly patient
Has a source of emboli No source
No history of occlusive arterial disease History of occlusive arterial disease
Other pulses present Other pulses may be absent
Angiography – Sharp cut off (Fontaine
sign), multiple occlusions, few collaterals
Angiography – Diffuse atherosclerosis,
irregular cutoff, well developed
collaterals

7. Source and Distribution of significant
Arterial Emboli

8. Pathophysiology
• Depends on –
– Degree of obstruction
– Site of occlusion
– Presence of collaterals
• Ischaemic metabolism – shifting from aerobic
to anaerobic.
• Different tissues tolerate ischaemia at
different rates

9. Cont..
• NERVES : First to be affected, IRREVERSIBLE
damage after 6 hours.
• MUSCLES – upto 6-10 hours
• SKIN : Last to show necrosis

10. Cont..
Alteration of cell wall
permeability
Sodium and water influx
Intracellular edema-
compartment syndrome

11. Cont..
Release of potassium
Hyperkalemia
Risk of cardiac arrest

12. Cont..
Muscle infarction – Release
of myoglobin
Myoglobinuria
Acute renal failure

13. Reperfusion injury Mechanism

14. Reference – Mastery Of Surgery (6th
edition, Volume 2, Pg 2332)
• A patient without underlying vascular disease
and an acute arterial blockage has
approximately “6 hours” for revascularisation
before irreversible functional tissue damage
occurs.
• Upon reperfusion, release of cellular products
may cause systemic organ injury such as renal
and pulmonary failure. These factors need to be
kept in consideration while treating these
patients.

15. Clinical Picture – 6 P’s

16. Acute late (Irreversible) Ischaemic
Limb
• Swollen limb
• Tender muscles
• Loss of muscle turgor
• Fixed cyanotic colour changes, marbling,
necrosis, desquamation
• Rigor mortis
• IN DOUBT – DO FASCIOTOMY

18. Diagnosis
• Colour doppler studies
• Contrast angiography
• Routine blood investigations
• Serum Markers – CPK and Neutrophilia
• 2d Echo
• DVT Scan – to look for paradoxical source

19. Cont ..
• Emphasizing the need for excellent judgment
is assessment of late SVS Grade III limb
ischemia. While perhaps obvious, it is
important to not attempt embolectomy in
those with non recoverable ischemia.

20. Cont ..
Factors underlying
mortality and
morbidity
Underlying
co-morbid
condition
Delay In
recognition and
revascularisation

21. Cont..
• Decreased amputation free survival is
associated with –
– Older age
– Malignancy
– CHF
– History of neurological disease
– Significant underlying atherosclerosis
– Poor arterial back bleeding at operation

22. Treatment

23. Treatment of Reversible Ischaemia
• Immediate anticoagulation by –
– Un-fractioned Heparin AND oral anticoagulants
• Open Surgical treatment
• Endovascular intervention

24. Algorithm

27. Thrombolysis
• Indications –
– Viable or marginally threatened limb
– Recent acute thrombosis (not suitable for
embolectomy or an old thrombi)
• Types : Systemic or Catheter Directed
• Agents – Streptokinase, Urokinase, tPA

28. Treatment of Irreversible Ischaemia
AMPUTATION
ANTICOAGULATION

29. Differential Diagnosis
• DVT
• Neurologic disorders eg paraplegia
• Low Cardiac Output
• Frost Bite and other vasospastic diseases
• Chronic limb ischaemia

30. Points to Note
• RCT between Endovascular intervention and
surgery –
– Rochester trial –
• No difference in limb salvagability
– TOPAS trial –
• No difference in limb salvagability
– STILE trial-
• Thrombolysis has inferior limb salvage rates at 1 year
along with an increased incidence of recurrent
ischaemia and major amputation

31. Conclusions and Recommendations
• Heparin should be administered as soon as the diagnosis has been
made.
• In a patient with viable or marginally threatened limb, imaging
studies can be obtained to guide therapeutic considerations.
• In a patient with immediately threatened limb, emergency
angiography followed by catheter based thrombolysis or
thrombectomy or open surgical revascularisation is indicated to
restore blood flow.

32. THANKS