Patients With Drug-Eluting Stents Should Take Anti-platelet Medication For 12 Months To Avoid Fatal Heart Attacks

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Main Category: Cardiovascular / Cardiology
Also Included In: Medical Devices / Diagnostics;  Blood / Hematology
Article Date: 17 Jan 2007 - 12:00 PDT

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Patients who have drug-eluting stents inserted into diseased arteries to prop them open should stay on anti-platelet medication for at least 12 months to reduce the risk of fatal heart attacks. This was the advice of an advisory panel from five medical societies, including the American Heart Association, the American College of Cardiology, and the American Dental Association.

Their report is to be published in a number of journals, including the journal of the American Heart Association Circulation.

Two anti-platelet agents that are commonly prescribed for preventing blood clots are ticlopidine (tradename Ticlid from Roche Holding AG) and clopidogrel (tradename Plavix marketed by Bristol-Myers Squibb and Sanofi-Aventis). They are a class of drug known as thienopyridines.

Aspirin is also an anti-platelet agent and is often prescribed in combination with a thienopyridine in a treatment that is known as dual antiplatelet therapy which is particularly effective at preventing stent thrombosis, or clotting.

Antiplatelet agents are taken by patients before they receive the stent and they stay on them afterwards to minimise the chance of the blood clotting or forming platelets inside the stent which would result in serious and sometimes fatal heart attack.

The report states that patients who come off the medication too soon are at much higher risk of developing blood clots and dying of heart attacks.

Dr Cindy Grines, chair of the advisory writing committee and also a cardiologist at William Beaumont Hospital in Royal Oak, Michigan, said: "We want to alert patients and healthcare professionals that this is a serious medical issue; they shouldn't even think about stopping antiplatelet therapy because it could result in heart attack or death."

The advisory panel says that the evidence is very clear and doctors and dentists should be very careful about taking patients off this medication too soon. If they feel it is necessary, for example to prevent prolonged bleeding after an operation, then they should only do so in consultation with the patient's cardiologist and there should be a plan to get them back on the medication as soon as possible afterwards. The preference would be for the operation to be delayed for at least a year, or for the patient to at least remain on aspirin by itself and then get back on the thienopyridine as soon as possible.

The panel refers to research studies where stent clots affected 29 per cent of patients who stopped antiplatelet therapy too soon. In a group of 500 people who were implanted with drug-eluting stents following a heart attack the mortality for those who stopped their medication was 7.5 per cent in the following 11 months compared to 0.7 per cent in those that did not. And in another study they found that stopping the anti-platelet medication was linked to a 30-fold increase in risk of stent thrombosis.

A stent is effectively a small tube of wire mesh that is inserted in a blocked artery to prop it open and restore normal blood flow.

Drug eluting stents are often preferred to bare stents as a way to keep blocked arteries open because they slowly discharge a chemical that stops scar tissue forming in the mesh and eventually blocking the blood flow. In a way this is a bit of an ironic situation because if it were possible to limit the scar tissue to a thin layer it could actually cover the mesh and stop it causing clots.

More information on Drug-Eluting Stents (angioplasty.org).

Click here for American Heart Association.

Written by: Catharine Paddock
Writer: Medical News Today


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