Chronic limb threatening ischaemia (CLTI), also known as critical limb ischaemia, is a severe blockage in the arteries of the lower extremities. It is an advanced stage of peripheral arterial disease. CLTI is characterised by severely diminished circulation, ischaemic pain, ulceration, tissue loss or gangrene. It is associated with high amputation and mortality rates, and poor quality of life.
CLTI needs urgent treatment to re-establish blood flow to the affected area and to prevent major amputation. Treatment options include medications, endovascular interventions (such as angioplasty, stents, laser atherectomy and directional atherectomy) and surgical treatments (such as bypass). Management of CLTI is described in NICE's guideline on peripheral arterial disease.
Preoperative investigation (such as angiography, arterial and venous duplex scan) is needed to assess the vascular system and its blood flow. During the operation, an arteriovenous fistula is created between the great saphenous vein (GSV) and the appropriate patent artery. The GSV is then anastomosed end‑to‑side to the artery below the knee. Side branches of the GSV to the ankle level are ligated and valvulotomy is done.
This procedure arterialises the venous arch of the foot, with GSV maintained in situ and without compromising the existing collateral circulation. The aim is to improve symptoms and salvage the affected lower extremity.