Medical Device Daily Executive Editor

One thing is certain in the cardiovascular segment of med-tech: you aren’t going to find any broad general agreement concerning the safety and best uses of drug-eluting stents (DES) — at least not any time soon. Additionally, don’t expect a great deal of consistency between early and late trial results.

The Society for Cardiovascular Angiography and Interventions (SCAI; Washington), at this year’s Congress of the European Society of Cardiology (Sophia Antipolis, France) in Vienna, issued an update report on the Swedish Coronary Angiography and Angiolasty Registry (SCAAR) registry. In contrast to its initial analysis of SCAAR, SCAI now says that longer-term data indicate that the use of DES is safe, and it minimized, given careful patient selection and follow-on drug compliance, that DES is safe.

The new analysis is expected to prop up confidence in DES technology which over the past several months has seen significant declines, in part because of the earlier report out of SCAAR, along with several other studies indicating increased thrombosis and death among DES-implanted patients compared to the use of bare-metal stents (BMS).

SCAI said that the new findings are “in direct contrast to last year’s findings based on shorter-term observation of patients from the [SCAAR] registry, which led to widespread concern about whether the devices cause dangerous blood clots and may have dissuaded some patients and their doctors from treatment with DES.”

A newer look at longer-term clinical experience with DES, the organization said, “translates into excellent news” for heart patients.

The report, however, probably should be considered in the context of other studies out of the Congress that continue to indicate late thrombosis following DES implantation, especially in emergency situations (Medical Device Daily, Sept. 5, 2007). And the reports continue to put the rate of late thrombosis at 1% to 2%, as compared to the SCAI’s estimate of .5% thrombosis.

In a statement SCAI said that SCAAR indicates that DES produces 50% less reclogging at the stent site compared to use of bare metal stents — no news there, since that has been claimed for DES devices since the beginning — and that more recent analysis of their use indicates no long-term risk.

Dr. Stefan James said that the study now has followed more than 13,000 patients for up to four years after DES implantation, and has shown that “drug-eluting stents are not dangerous.”

Additionally, however, that umbrella interpretation was embedded amongst several broad qualifiers.

The SCAI in its statement said that the “new findings ... underscore the crucial importance of training physicians in the proper selection of patients, proper implantation technique, and in prescribing a strict regimen of medications that prevent blood clots in the first one to two years after DES implantation.”

Maintaining patient compliance on such a regimen is, of course, a problem, especially for those patients who do not have insurance coverage for these expensive drugs, it has been found.

Describing the findings as “reassuring news for patients with cardiovascular disease,” SCAI President Bonnie Weiner, MD, president of SCAI and professor of medicine and interim chair of cardiovascular medicine at St. Vincent Hospital at Worcester Medical Center (Worcester, Massachusetts), cited patient confusion as the result of stories reporting problems, including increased fatalities, among DES-implanted patients, and that the organization has been “concerned that last year’s headlines may have prevented some patients from getting the best therapy.”

She said that the newer report on SCAAR “is consistent with all other data on the benefits of DES and reaffirms the value of drug-eluting stents as a highly effective tool to open blocked arteries and stop regrowth of plaque and scar tissue in those vessels.”

And Steven Bailey, MD, interim chief of the division of cardiology at the University of Texas Health Sciences Center (San Antonio), emphasized that the new data “represent ‘real-world’ outcomes that show how Swedish doctors’ technique improved over time because of more experience implanting drug-eluting stents resulting in improved outcomes for patients. “Our patients can be reassured by these findings. If their interventional cardiologist chooses to implant a drug-eluting stent, they are receiving a safe and effective treatment.”

Explaining the new findings, Weiner also pointed to indications that physicians’ technique with the stents has improved and that DES-implanted patients are now more likely to be on strict regimens of anti-clotting medications for a longer period.

SCAI said that “both physicians and patients need further education on the importance of a strict regimen of both clopidogrel and aspirin, two drugs that help prevent the formation of blood clots ... and that the patient must be “willing and able to comply to a long-term regimen of clopidogrel and aspirin.”

In still more news concerning DES from the Congress:

Boston Scientific (Natick, Massachustts) reported results from the TAXUS WOMAN study, a gender-specific analysis of the TAXUS II, IV, V and VI trials assessing the efficacy data of its TAXUS paclitaxel-eluting DES in women undergoing coronary revascularization.

The study found paclitaxel-eluting stents to have similar clinical outcomes in women and men, despite the higher risk profile in women patients.

“This study of data from the TAXUS trials offers encouraging news for women with coronary artery disease,” said Ghada Mikhail, MD, consultant cardiologist at St Mary’s Hospital Trust (London). “Previous trials and registries have demonstrated a less favorable clinical outcome in women compared to men when undergoing coronary revascularization with bare-metal stents. That difference has been previously explained by the smaller vessels and higher risk profile seen in women.

“These data show, however, that the TAXUS paclitaxel-eluting coronary stent works equally well in women, maintaining its anti-restenotic efficacy advantages and positive safety profile relative to bare-metal stents.”

The TAXUS II, IV, V and VI trials evaluated the performance of the TAXUS compared to a BMS control in patients with coronary artery disease. The TAXUS WOMAN study analyzed pooled results of the women enrolled in these TAXUS trials and compared them with the corresponding endpoints in men.

Of the 3,445 patients enrolled in the TAXUS trials between June 2001 and March 2004, 955 (27.7%) were women. Of these women, 480 received the Taxus and 475 received a BMS. Of the 2,490 men enrolled, 1,238 received PES and 1,252 received BMS. As compared to men, women were older (mean age 65.4 +/- 10.9 years vs. 61.0 +/- 10.4 years), had smaller body surface area (1.80 +/- 0.19m² vs. 2.05 +/- 0.20m²), had more diabetes (30.4% vs. 21.0%), had more hypertension (78.0% vs. 65.1%), had smaller vessels (pre-procedure reference vessel diameter 2.63 +/- 0.46mm vs. 2.78 +/- 0.52mm), and had more history of coronary artery disease (62.2% vs. 54.7%) (p for all <0.001).

There were no other significant differences in baseline demographics, lesion or procedural characteristics between the Taxus and BMS groups in both genders.