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Coronary angioplasty and stenting

 
The purpose of a coronary angioplasty (angio = artery and plasty = opening) is to restore or improve blood flow to the heart muscle in order to address coronary heart disease that can cause angina or heart attack.
 
The procedure involves inflating small sausage-shaped balloons inside the coronary arteries (the arteries supplying blood to the heart muscle) that have been narrowed as a result of atherosclerosis (the build-up of fatty deposits, or plaques, in the arteries).  Stents are positioned inside the artery as a scaffold to help keep the artery open.
 
Coronary angioplasty is a non-surgical procedure that does not usually require an overnight stay in hospital. 

Balloon coronary angioplasty alone was once the main non-surgical technique for treating narrowed coronary arteries. However, today almost all coronary angioplasty procedures involve the use of a coronary stent.
 
A coronary stent is a small mesh tube that is positioned inside a narrowed area in an artery referred to as a stenosis (plural = stenoses), and acts as an internal scaffold to help keep the artery open. The majority of stents have a medication coated on them and are known as drug-eluting stents (DES). Once the stent is deployed in the artery the medication is slowly released into the surrounding area to help reduce the chance of the artery re-narrowing (known as re-stenosis). 
 
Most stents are made of metal but some drug-eluting bioabsorbable stents are  made of a dissolvable polymer. Stents without a medication coating are known as bare metal stents (BMS).

Coronary angioplasty and stenting can be performed on an emergency basis during a heart attack to open a blocked or narrowed artery in order to restore blood flow; or they can be performed as a planned procedure. 

The procedure

Coronary angioplasty and stenting are usually able to be performed as a day-stay procedure, though sometimes an overnight stay in hospital may be required. After admission, an electrocardiogram (a tracing of the heart’s electrical activity) and blood tests (to check kidney function and blood counts) will be performed. On some occasions a chest x-ray may also be taken.

Baseline measurement of the blood pressure, heart rate and temperature will be recorded. The entry site for the procedure will be shaved. The patient cannot eat or drink anything for a few hours before the procedure.

The patient will be mildly sedated but awake during the procedure and staff will monitor heart rhythm and rate, blood pressure and blood oxygen levels.

A narrow plastic tube (an introducer sheath) will be inserted into an artery in the wrist (radial approach) or the groin (femoral approach). A local anaesthetic is used to numb the insertion site before the introducer sheath is positioned in the artery. A catheter (a thin flexible tube) is inserted though the introducer sheath and is positioned at the entrance to the coronary arteries. The cardiologist injects x-ray-detectable dye through the catheter into the coronary arteries, enabling them to be seen on an x-ray screen. This procedure is known as a coronary angiogram.

A specialised x-ray camera is positioned over the chest during the procedure and is able to move to a number of positions in order for x-ray pictures to be taken from different angles. If a narrowed area is identified, and it is deemed to be suitable for treatment with coronary angioplasty and stenting, this is usually able to be done straight away.

A balloon-tipped catheter is passed through the introducer sheath and is threaded up into the coronary arteries. It is positioned within the narrowed portion of the artery and is checked on the x-ray screen. Once correctly positioned, the balloon is inflated. The inflated balloon opens the narrowed artery by compressing the plaque and slightly stretching the artery wall. Each balloon catheter is selected to be approximately the same size as the artery and the balloon is made to only inflate to a specific size.
 
Coronary Angioplasty
 
Coronary angioplasty 1
Graphic courtesy of A. Bonsall and MedicineNet.com
 
A stent is deployed in a similar way. The unexpanded stent is tightly crimped on a balloon tipped catheter. The stent is positioned within the narrowed portion of the artery and the balloon is expanded, opening the stent and pushing it up against the artery wall. The balloon is then deflated and removed, leaving the stent behind to act as an internal scaffold to keep the artery open. Once the stent is in place, it cannot be removed.

Occasionally another balloon tipped catheter is inflated inside the stent to ensure that it is fully expanded. When the cardiologist is satisfied that the artery has been opened sufficiently, and the stent is adequately deployed, more x-ray pictures of the artery will be taken to see how blood flow through the artery has improved. The catheter is then removed.

If the procedure was performed via the wrist artery the introducer sheath is removed at the end of the procedure and a pressure band is applied to help seal the incision site. If the procedure was performed via the groin artery the introducer sheath will be removed on the ward two to four hours after the procedure.

Recovery

Following the procedure, the patient is returned to the ward and blood pressure, heart rate and heart rhythm will be monitored. They will advise when the patient can get out of bed and move around. Fluids may be given intravenously through a small needle (drip) inserted in the hand or arm. This fluid will help to flush the x-ray dye from the kidneys.

Prior to discharge a further ECG and blood tests may be taken. A doctor or nurse will advise about recovery and activity guidelines following discharge from hospital. Some activities, such as heavy lifting, should be avoided for at least a week. Land Transport Safety Authority (LTSA) guidelines prohibit driving for at least two days after a coronary angioplasty. The patient will therefore need someone to drive them home after the procedure.

Medications will be prescribed before the patient is discharged. These may or may not be the same medications that the patient was taking before admission to hospital. If a stent has been deployed it is usual to have dual anti-platelet therapy. This consists of aspirin and an anti-platelet medication such as clopidogrel or ticagrelor. It is very important to take these medications as prescribed as they help to prevent blood clots forming within the stent. Dual anti-platelet therapy may be prescribed for a duration of up to 12 months.

A follow up appointment with the cardiologist is usually made in order to assess recovery and progress.

Complications

The risks associated with coronary angioplasty are very small. It is important to discuss these with the cardiologist prior to signing the consent form for the procedure. Risks of coronary angioplasty include:

  • Abrupt closure of the coronary artery 
  • An allergic reaction to the x-ray dye 
  • Heart attack or stroke 
  • Damage to the coronary artery 
  • Damage to the catheter insertion site.

In a small percentage of cases the coronary artery narrows again soon after the angioplasty. If re-stenosis is going to occur, it usually does so within the first six months after the angioplasty is performed. In these cases, a repeat angioplasty or coronary artery bypass surgery may be recommended.  In a small number of cases (about one to two per cent) emergency coronary bypass surgery is necessary because of complications of the coronary angioplasty and stenting procedure.

Lifestyle changes

Although having a coronary angioplasty reduces the symptoms of heart disease it is not a cure for heart disease.  Therefore, to lower the risk of experiencing future heart problems, it is important that recipients of a coronary angioplasty adopt (and maintain) lifestyle changes.  These include stopping smoking, losing weight, eating a heart-healthy diet and establishing an appropriate exercise routine.

References

Heart Foundation (2015). A guide to angioplasty (Booklet). Auckland: National Heart Foundation of New Zealand. https://www.heartfoundation.org.nz/shop/heart-healthcare/angiography-and-angioplasty.pdf
Heart Foundation (Date not stated). Angioplasty and stents (Web Page). Auckland: National Heart Foundation of New Zealand. https://www.heartfoundation.org.nz/your-heart/heart-treatments/angioplasty-and-stents [Accessed: 20/11/17]
NHS Choices (2015). Coronary angioplasty and stent insertion (Web Page). Redditch: National Health Service (NHS)
England. https://www.nhs.uk/conditions/coronary-angioplasty/ [Accessed: 20/11/17]
Stouffer, G.A. (2016). Percutaneous coronary intervention (PCI) (Web page). Medscape Drugs and Diseases. New York, NY: WebMD LLC. https://emedicine.medscape.com/article/161446-overview [Accessed: 20/11/17]


Last Reviewed – December 2017 

 

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