Artery: Peripheral Angioplasty
Peripheral arterial disease is a condition where the arteries that carry blood to the legs become narrowed due to cholesterol deposition along the inner lining of the arteries. Delivery of oxygen-rich blood becomes reduced and this may lead to problems like pain, ischaemic ulcers and toe gangrene.
One option for improving the blood flow is to perform an angioplasty. This procedure involves passing a balloon across the segment of artery that is narrowed. Inflation of the balloon will widen the lumen of the artery to allow more blood flow across.
For accurate assessment and planning for intervention, a Duplex scan of the affected leg is done. This allows visualisation of the arteries in the leg as well as the degree of narrowing of the affected vessels. Other alternative investigations are CT angiogram and MR angiogram of the affected leg.
Patients with diabetes who are on metformin (Glucophage) will have to stop their metformin 2 days prior to the angioplasty as their medication will interact with the intravenous contrast given during the procedure.
Patients who are on anticoagulants such as warfarin will need to have their warfarin therapy converted to short acting injections before the procedure.
Patients who are on antiplatelet agents like aspirin, clopidogrel (Plavix) or ticlopidine (Ticlid) will have to stop taking them for between 5 to 7 days prior to the angioplasty to reduce the risk of bleeding.
This procedure is usually done in the Angiography Suite or the Operating Theatre.
Before starting the procedure, a urinary catheter will be inserted to empty the bladder. This is also for the patient’s comfort after the procedure.
The angioplasty is usually performed via the patient’s femoral artery in the groin. After prepping the area, a local anaesthetic injection will be given. The femoral artery is localised with an ultrasound scanner and is punctured with a sheath that allows easy access into the artery for the passage of the wires and catheters.
During the angioplasty procedure, a special contrast agent will be injected into the arteries. This will allow the surgeon to visualise the arteries and to see the areas of narrowing or blockage. After determining the area of narrowing, a wire is passed across the area of narrowing. The angioplasty balloon is guided to the narrowed area over the wire. The balloon is then inflated to widen the narrowed area.
Arteries which are completely blocked, or occluded, are harder to treat as there is no lumen for the wire to pass through. In such a situation, the surgeon may try to pass the wire along the wall of the artery and re-enter the lumen of the artery below. This technique is called Sub-Intimal Angioplasty and allows arteries that are blocked to be re-opened.
After the angioplasty, the sheath in the groin is removed and manual pressure applied to the groin for 15 to 20 minutes to prevent bleeding.
Upon returning to the ward, the patient will usually have to lie flat in bed for another 4 to 6 hours. The patient is advised not to sit up, stand or walk as this will involve flexion at the hip. This may cause the puncture site in the groin to bleed and lead to severe bleeding and haematoma formation.
After overnight observation, the patient can usually be discharged the next day.
1. Groin bleeding from the femoral puncture
2. Groin haematoma, or blood clot
3. Femoral artery injury
- Putting the sheath into the femoral artery can occasionally cause damage to the artery, especially if the artery was already very calcified.
- Damage to the femoral artery may require surgical repair.
4. Arterial rupture
- The diseased and narrowed artery is usually heavily calcified and hardened. Occasionally, when the balloon is inflated, it may actually cause the underlying artery to rupture and bleed.
5. Arterial thrombosis
- During the angioplasty, blood may clot in the artery causing it to become blocked. This is known as arterial thrombosis.
- If this occurs, the clots will need to be removed surgically or dissolved with a special chemical agent, called thrombolysis.
6. Distal embolism
- During the ballooning process, small pieces of the cholesterol plaque or small clots may be dislodged. Once dislodged, they will flow downwards towards the feet and may cause blockage of the arteries further below.
7. Intimal dissection and intimal flap
- After ballooning a diseased artery, the inner lining of the artery may become torn and create a small flap which can impede blood flow. In order to prevent the flap from blocking off the artery, a small metal tube called a stent may have to be deployed across the affected area.
8. Kidney impairment
- The use of the contrast agent during the angioplasty to visualize the arteries is associated with a small risk of damaging the kidney function. This occurs in approximately 5 to 10% of patients going for angioplasty.