Treatment Of Heart Disease With Angioplasty And Stents

By Dr. Harold Gunatillake - FRCS, FACS, AM (Sing) Health Writer

Gone are the days when patients underwent major open-heart surgery for blocked coronary arteries when one, two or three main arteries were partially or totally blocked. Today, such major surgery is replaced by a minor procedure — angioplasty and stent placement — to unblock such vessels and maintain the blood flow. Angioplasty is a non-surgical procedure and you could go home after a night’s rest in a hospital bed. This is becoming the most common procedure done to people who suffer atherosclerotic heart disease, the most common condition among the aging population.

The procedure is also referred to as Percutaneous Coronary Intervention (PCI). It involves a temporary insertion of a catheter with a tiny balloon at its tip, to blow up the blocked and clogged artery to open wide for the blood to flow through.

The procedure is done in a cardiac lab and the fear and stress of being trolleyed into an operating theatre is non-existent. The procedure is done not even by a surgeon, but by a specialised cardiologist and a team of cardiac nurses and technicians. In the lab, under local anaesthesia, one of the groin areas will be numbed after giving medication for relaxation. Before that, a few preliminary blood tests would be done.

The procedure is called Angioplasty. First, a cardiac catheterization is done through the numbed groin; next a sheath (a thin plastic tube) is inserted through the groin. Rarely, the procedure is also done by cardiologists through the arm. Then a long narrow hollow tube called the catheter is passed through the sheath and guided up the blood vessel to the arteries, on the surface of the heart.

After negotiating into the main coronary arteries seen visually through an x-ray monitor screen, a small amount of contrast dye is injected through the catheter. Photographs are also taken as the dye moves through the heart chambers, valves and major vessels. These pictures will enable the cardiologist to assess the blockage of arteries and further check on whether the heart valves are working properly.

After blowing up the clogged artery, the patency is maintained with the replacement of a small metal coil called a stent, which decreases the chance of its narrowing again. The newer stents are coated with medication to help keep the artery open for a longer period. These devices are called drug eluting stents. The first generation stents were just bare-metal stents.

Patients with coronary vessel clotting will have many symptoms of sudden or slow onset. Chest discomfort or pain with shortness of breath is the most common symptom. One must get an ambulance and rush to the closest hospital without delay, where facilities are available for cardiac management. Angioplasty can also be used during a heart attack to quickly open a blocked artery and reduce the amount of damage to your heart.

After the procedure your chest pain should decrease and may have a better ability to exercise. However, if the symptoms return you should contact your cardiologist immediately. With successful angioplasty you avoid invasive surgical procedures like open heart and bypass surgery.

If many vessels are blocked or narrowed (seen on an angiography), with reduced heart function or diabetes, bypass surgery may be considered by the cardiologist.

Let’s discuss about the various types of cardiac stents.
Titan stent vs. Taxus stent: Dr. Pasi Karjalainen from Satakunta Hospital Pori Hospital in Finland presented data about the Titan stent Pori Registry during the Cardiovascular Research Foundation’s 17th Annual Transcatheter Cardiovascular Therapeutics (TCT 2005) scientific symposia moderated by Dr E.Grube. Dr Karjalainen concluded that the Titan stent is a safe and durable treatment option in the real world of unselected patients (The Titan stent is manufactured by Hexacath).

Drug–eluting stent (DES): This is a scaffold, placed into narrowed diseased coronary artery that slowly releases a drug to block cell proliferation. This prevents fibrous tissue formation with clots to block the stented artery. An example of a drug-eluting stent is the Taxus Express Paclitaxel-Eluting Coronary Stent.

These stents were approved by FDA after clinical trials revealed that they were superior statistically to bare metal stents (BMS). Developers of drug-eluting stents used the devices themselves as a tool for delivering medication directly to the arterial wall, limiting side effects unlike the non-eluting stents. These stents limit the growth of scar tissue, thus reducing the likelihood of stent stenosis (narrowing). The first successful trials were sirolimus-eluting stents. Presently, paclitaxel- eluting stents are used with FDA approval. The third variety is the Xience V everolimus eluting stent, also approved by FDA in July 2008 is available in Europe and other international markets.

Risks

Angiography though a less invasive procedure carries some risks that you should know. Re-stenosis (re-narrowing of the vessels), one drawback of the procedure is that within a few months an artery can get narrowed due to the continuous thickening of the arteries (atherosclerosis), which cannot be prevented. Without the insertion of a stent 30-40% of cases can re-stenose. The original metal stents reduced re-stenosis to less than 20 per cent and the drug eluting stents have reduced the risk of re-narrowing to less than 10 percent. So always ask the cardiologist for the latter stents, though more expensive.

Immediately after stent placement you will be started on blood thinning medication which you need to take regularly for over five years or more. Clopidogrel and aspirin are the current medications prescribed for this purpose. There may be bleeding at the site of insertion of the catheter in the groin. Sometimes sandbag pressure for a few hours and bed rest may be required to prevent bleeding.

Risks during the procedure

A minor heart attack could occur during the catheterisation and insertion of stent. Minor strokes have been reported due to dislodgement of plaques from the artery walls.  You may also experience chest pain and discomfort during the procedure as the balloon temporarily blocks blood flow to a part of your heart.

Coronary artery damage: Where the artery can get torn during the procedure. In such an event immediate open heart surgery will be planned.

Abnormal heart rhythm: This is a possibility due to irritation of the heart. These are short lived; prolonged irregularities may require the placement of a pace-maker.

Kidney disease: The aggravation of kidney function particularly in diabetics and those with kidney disease is higher than that expected due to the large amounts of dye used. Hence, kidneys need to be flushed by drinking large amounts of water and certain diabetic medications like metformin are stopped 24 hours prior to the procedure. In the hands of experienced cardiologists and with availability of modern day technology, it is estimated that the risk of death during a stent procedure is less than 1% and requiring emergency bypass surgery is around 2% or less. It is a very safe procedure and is carried out all over the world and is quite popular.

When you reach home after the procedure you need to drink plenty of fluids to help rid your body of the contrast dye used to detect the blockages. No exercises and lifting heavy objects for about a week. Travelling far on a holiday is not recommended for about three months.

What happens to the stent

The stent is completely covered by the inner lining tissues in about six weeks. Clot formation is possible during this period (one chance out of 200). They need prompt treatment and the majority of these stents can be reopened.

Angioplasty with stent placement is not a cure. The procedure only opens the arterial blood flow in the main coronary vessels, whilst the process of atherosclerosis will progress nevertheless. One needs to diminish the progress of atherosclerosis by a strict disciplined life.

-     No smoking.
-     Exercise for one hour daily.
-     Take your blood pressure medication daily and check your BP regularly.
-     Check your blood cholesterol levels every six months and take statin medication to keep the range as low as possible.
-     Eat a balanced diet with plenty of fruits, low saturated fatty acid foods such as dairy products and red meat.
-     Eat plenty of fish, vegetables, nuts, and seeds.
-     If you suffer from diabetes go on low glycaemic Index (GI) foods.
-     Check your blood sugar level daily and control your blood sugar levels with medication and diet.
-     Get a HbA1c blood test every three months to verify the control of your blood sugar level.
-     Increase your consumption of coconut meat daily in your ‘sambol’ and curries. Use the oil for cooking.
-     Restrict alcohol consumption. A glass of red wine daily is recommended.
-     Eat an egg daily especially for your vitamins and proteins.
-     Keep your weight within the average normal range.
-     Obesity is a risk factor.
-     Reduce your stress levels at work, and have a happy relationship with your family.
-     Visit your cardiologist every six months for a full check up.
-    With above regime you will not go wrong.