The stents under investigation were those made by Johnson & Johnson and Boston Scientific after concerns that patients inserted with these devices may be at a "small but higher risk" of developing blood clots compared to those with older-generation metal stents.
The FDA concluded that when the drug-eluting stents were used in patients according to their indication - those with one blockage in a large blood vessel -- the benefits outweigh the risks because they reduce the need for surgical procedure to open up the clogged arteries.
These patients can continue to have the stents inserted for a period of three to six months, as the stent labels currently recommend, the panel said.
However, the FDA did express concerns over the device being used off-label in unhealthy patients with more than one blockage, often in smaller blood vessels.
There is particular concern over this practice considering that over 60 per cent of drug-eluting cardiac stents are fitted in patients off-label.
According to the panel, patients with off-label drug-eluting stents have higher blood clot, heart attack and death rates than patients who are indicated for the stents, although it did concede that due to the fact that these patients are a lot sicker, higher complications rates should be expected.
Because of this, the FDA panel concluded that stent labels must now include a warning that patients in off-label groups have higher complication rates than those who are approved for the devices. These label updates will be in place as soon as possible, the agency said.
In addition, the use of anti-clotting therapy in off-label patients for up to one year was also recommended.
Finally the panel concluded that more information on these drug-eluting stents is required and data should be gathered in the form of larger and longer clinical studies, specifically looking at the risk of blood clots.
Drug-eluting stents are small wire mesh tubes that are inserted into a clotted artery to open it up and restore adequate blood flow. They are coated in drugs that are gradually released in order to stop scar tissue from forming in the arteries after angioplasty which can re-block the artery - something that commonly occurs with bare metal stents.
Over three million people in the US are fitted with a drug-eluting stent and the market is now worth over $5bn.
More of these devices are on the way - Medtronic and Abbott Laboratories have filed for FDA approval of their drug-eluting stents, with approval expected in mid-2007 and mid-2008 respectively.
It is unclear whether the recent uncertainty over these devices will delay these approvals in any way or require the manufacturers to undertake further studies before approval.