Drug-eluting stents still worry cardiologists

Five-year and final safety data demonstrating long-term safety and efficacy of drug-eluting stents has been presented at the annual European Society of Cardiology (ESC) Congress in Vienna, Austria.

Under review were US-based Boston Scientific and Johnson & Johnson's (J&J) Taxus II paclitaxel stent and Cypher stent, respectively.

Dr Gabriel Steg of the Paris-based Hospital Bichat-Claude Bernard examined patients who were given stents to hold open blocked cardiac arteries, following a ST segment elevation myocardial infarction (STEMI), a serious form of heart attack.

For the first six months, patients on drug-eluting stents and those on bare metal versions experienced similar effects. After 180 days, however, the treatment experience of the patients differed, with the drug stent patients 4.7 times more likely to die (mortality rate 8.6 per cent). Steg explained that the trend might reveal a high thrombosis risk in this group of patients, who represent 10 to 20 per cent of current coronary stent procedures.

Both Boston and J&J's stents have been criticised over safety and efficacy concerns, which have impacted sales. The drug-coated devices have been linked to a slightly higher risk of certain blood clots than bare-metal versions.

Doctors at the ESC meeting said the finding showed the need to be very selective about giving drug stents to the appropriate patients.

At the meeting, Boston argued that its Taxus drug-coated coronary stent had continued to demonstrate long-term safety and efficacy after publishing the five-year and final results of its Taxus II clinical trial.

The trial results showed there were no instances of additional stent blood clotting in patients fitted with a Taxus stent between years four and five of the trial, compared with one instance in the bare metal stent comparison group over the same period.

J&J's Cordis unit also said its Cypher stent was associated with lower rates of cardiac death, blood clots and heart attack than Taxus in the study, but the differences were statistically insignificant.

Dr Spencer Grace, a spokesman for the American College of Cardiology, said such overall figures could hide markedly different trends for different groups: "STEMI is not a particularly good indication for drug-eluting stents for a host of reasons, because what you gain is very small since there is a not a lot of artery re-narrowing in these patients. The main thing you are trying to do with these patients is open the artery and stop the heart attack and that is done no better with a drug-eluting than a bare metal stent."

Bank of America analysts estimated that the world market for drug stents will fall USD 1bn in 2007 to USD 4.3bn. The high cost of the devices has also made regulators and healthcare providers reassess their value, with the UKís cost-effectiveness body the National Institute of Health and Clinical Excellence (NICE) considering stopping payments.