Drug-eluting stents have revolutionised the treatment of coronary artery disease over the last few years and all but consigned heart surgery to second-line use. But a new study published in the Journal of the American Medical Association (May 4) has suggested that these devices may be associated with a higher incidence of complications than first thought.
One of the reasons for the enormous commercial success of the coated stents currently on the market – Johnson & Johnson’s Cypher (based on sirolimus) and Boston Scientific’s Taxus (based on paclitaxel) – was their immense improvement over earlier bare metal stents in blocking restenosis [[18/03/04d]] [[05/03/04d]]. The process, in which the lining of the blood vessel opened using a stent grows through the scaffold and causes it to reblock, was a serious problem with the early generation of stents. By solving the problem, sales of Cypher and Taxus were able to quickly ramp up and reached about $3 billion last year.
Another complication associated with stenting is thrombosis, the formation of blood clots within the stent that block the blood vessel. In the latest study, conducted in ‘real world’ patients, Italian researchers have found that the rate of in-stent restenosis is much higher than was seen in clinical trials of the drug-eluting stents. Moreover, the risk of thrombosis extended beyond the 30-day period after stenting, generally considered the high-risk period for clot formation, out to 90 days.
The researchers, headed by Ioannis Iakovou of the of the Centro Cuore Columbus and San Raffaele Hospital in Milan, Italy, note that the finding suggests that greater care should be taken in monitoring patients beyond the 30-day threshold. In particular, it is important that antiplatelet therapy with Sanofi-Aventis and Bristol-Myers Squibb’s Plavix (clopidogrel), Roche’s Ticlid (ticlopidine) is not stopped prematurely, they write.