Artery: Peripheral Bypass Surgery
Peripheral arterial disease is a condition where arteries that carry blood to the legs become narrowed as a result of cholesterol deposition along the inner lining of the arteries. The delivery of oxygen-rich blood becomes reduced and this may lead to problems like pain, ischaemic ulcers and toe gangrene.
Peripheral bypass surgery improves the lower limb ischaemia by surgically creating a new passage to bring oxygen-rich blood to the peripheries, bypassing the diseased blood vessels.
Bypass surgery is usually done for patients with Critical Limb Ischaemia. These patients usually present with:
- Toe or foot gangrene
- Non-healing ischaemic ulcers
- Severe rest pain at night
Patient selection is important to ensure a good outcome. Patients who meet the following criteria have better outcomes after bypass surgery:
- Good pre-morbid condition
- Good ambulatory status
- Cardiac function, e.g. Left Ventricular Ejection Fraction >40%
- Size of target vessel, at least 2.0 to 2.5mm
For accurate assessment and planning, a Duplex scan of the affected leg is done. This allows assessment of the extent and degree of narrowing of the affected vessels. The size of the Long Saphenous Vein (LSV) can be assessed to see if it is suitable for use as a conduit.
Prior to surgery, a full cardiac assessment is undertaken and medications optimised as cardiac complications are one of the major complications after surgery.
This surgery can be done under General or Regional Anaesthesia.
The first step of the surgery is to select a suitable artery at the lower leg where the bypass graft will be joined. The target artery is dissected out and an angiogram is done to ensure that the blood circulation from the target artery will reach the foot.
Once the target artery is found suitable, the LSV is harvested. If the LSV is not suitable to be used as a conduit, a prosthetic graft is used. A groin incision is made and the femoral artery dissected. The conduit is tunnelled in between and then sutured onto the inflow artery at the top and the target artery at the bottom.
The flow of blood in the conduit is checked with a handheld Doppler. Once the flow is satisfactory, the wounds are closed.
The patient is monitored in the high dependency ward for the first 24 hours. The patient’s vital signs and flow in the bypass graft are monitored as there is a small chance that the graft may become thrombosed in the first 24 to 48 hours after the surgery.
The patient will be able to drink fluids the next day after surgery and have food 24 hours after the surgery. After 3 days, the physiotherapist will help the patient to get out of bed and stand up. The patient may start walking about 5 days after surgery.
The wounds will usually take 7 to 10 days to heal and the sutures can be removed after 12 to 14 days.
Most patients after surgery will need to take at least one antiplatelet medication (e.g. aspirin or clopidogrel (Plavix)). This will usually need to be taken for life. For bypasses below the knee using a prosthetic graft, full anticoagulation with warfarin may be advised.
Mortality risk for this surgery is dependent on the patient’s initial cardiac status. In general, the risk is between 2-6%.
Complications that may occur include:
- Heart complications, e.g. heart attack, heart failure
- Renal impairment
- Wound infection
- Graft infection, especially with a prosthetic graft
- Distal embolization
- Graft thrombosis
- Failure of bypass. If severe, this may lead to the leg being amputated.