|The deployment of drug-eluting stents, such as the Endeavor stent from Medtronic, may be on the rise again. (Source: Medtronic)|
The utilization of drug-eluting stents may be poised for a comeback based on recent clinical studies that found they have value despite some risks. Industry analysts, however, suggest that there their usage has plateaued and they can not maintain their initial groundbreaking sales.
While studies have emerged over the past year concerning drug-eluting stents (DES), a few analyses and trials have been particularly influential in adversely affecting the stents’ utilization rates. A spate of negative outcomes—sensationalized by the mainstream press and/or taken to heart by cardiologists—have since been contradicted through extended investigation, further analyses, or paradoxical trial outcomes. This trend may solidly position DES to regain some of the market losses they endured over the past year.
DES were originally brought to the market to retard in-stent restenosis, which occurs in about 10 percent of DES cases compared to 40 percent of bare metal stent (BMS) cases, according to Venkat Rajan, medical device industry analyst for Frost & Sullivan, a San-Diego based market research firm.
Despite the low price and easy reimbursement for BMS, they hold a small percent of the market. In 2006, 300,000 BMS were deployed in the United States, compared to 1.2 million DES. Last year, the number of DES deployments in the States dipped by approximately 100,000, acording to Rajan. While recent positive clinical outcomes have initiated a shift toward greater DES utilization, analysts say the “peak” years may be over.
In February 2007, Lagerqvist et al published three-year results from the Swedish Coronary Angiography and Angioplasty Registry (SCAAR) analysis in the New England Journal of Medicine (NEJM). The study included all patients treated with stents in Sweden between 2003 and 2004—6,033 drug-eluting and 13,738 bare metal. Researchers found no difference in the composite of death and myocardial infarction over three years of follow-up. Researchers did find that DES-treated patients had significantly higher adverse event rates (18 percent) after six months, in particular, stent thrombosis, over the follow-up period.
The SCAAR registry results had a devastating effect on the DES market, mainly because of widespread media coverage sensationalizing the apparent increased risk of death with DES.
“At their peak usage rates, DES were being deployed into 90 percent of patients receiving stents in this country. Now it’s as low as 62 percent, said Stephen Ellis, MD, an interventional cardiologist at the Cleveland Clinic.
Because DES immediately achieved its highest potential of 90 percent upon release, the market was bound to endure a downturn at some point, according to Frost and Sullivan’s Rajan.
In Sweden, the home of the SCAAR Registry, the use of drug-eluting stents dropped from 60 percent to 10 percent nearly a year after the initial registry was released, according to a report in the September 2007 NEJM by Stefan K. James, MD, a
As a result of the negative effects of the registry, the SCAAR investigators extended their study to include more patients. Their latest findings, presented at the 2007 European Society of Cardiology Congress, show no difference between DES and BMS in terms of adverse side-effects when patients are followed out to four years, as opposed to three.
The updated SCAAR study group analysis is based on a one- to four-year follow-up of more than 35,000 patients, who received nearly 62,000 stents: 21,480 patients with only BMS and 13,786 patients who received at least one DES.
There is some debate regarding individual comparisons of Cypher (Cordis) and Taxus (Boston Scientific), or sirolimus-eluting stents and paclitaxel-eluting stents. Some studies suggest a slight edge for Cypher regarding in-stent restenosis and late stent thrombosis, but the difference seldom comes into play, said Ellis.
The Settler et al meta-analysis, one of the most influential large registries in the last year, examined 38 randomized trials involving 18,023 patients. It compared sirolimus-eluting stents, paclitaxel-eluting stents and BMS to each other. Researchers found that the sirolimus-eluting stents were associated with lower risk of MI during follow-up than paclitaxel-eluting stents and bare metal stents, although mortality rates were similar. The paclitaxel-eluting