American College of Cardiology

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April 19, 2005

“Women did significantly better with the paclitaxel-eluting TAXUS stent than with the bare metal stent; and in most respects they did seem to respond similarly to men,” said Gregg W. Stone, M.D., F.A.C.C., at the Columbia University Medical Center and Cardiovascular Research Foundation in New York, New York. “However, it is important to point out that the results of this study apply only to the types of patients that were enrolled in this study; and this study excluded a lot of high-risk situations,” he added.

Dr. Stone said further studies are needed before reaching final conclusions about the benefits of this drug-eluting stent for male and female patients who have had heart attacks, bypass procedure using vein grafts, and other conditions.

This analysis used data from the TAXUS-IV trial, which compared the safety and effectiveness of the slow-release, polymer-based, paclitaxel-eluting TAXUS stent to that of the bare-metal version of the same stent, known as the EXPRESS stent. The trial involved 1,314 patients who underwent elective catheter procedures to open narrowings in coronary arteries. The slow release of paclitaxel is intended to inhibit tissue proliferation around the wire mesh stent because it could again block the artery.

The investigators at 70 different institutions, including lead author Alexandra J. Lansky, M.D., F.A.C.C., randomly assigned 662 patients (187 women and 475 men) to receive TAXUS stents and 652 patients (180 women and 472 men) to receive the bare-metal EXPRESS stents.

According to the unadjusted results, women were more likely than men to need a second procedure to re-open the target coronary artery within one year (7.6% vs. 3.2%, p = 0.03). However, on average, the women were older, more likely to have other problems such as diabetes, heart failure and hypertension, and were smaller, with smaller coronary arteries than the men. Once these risk factors were taken into account, there was no statistically significant difference between women and men in either the need for a repeat procedure or other measures of restenosis.

The researchers noted that this trial did not include enough patients to detect small differences in infrequent events, such as clots in a stent, heart attacks shortly after procedure or death. Also, this trial involved only the paclitaxel-eluting TAXUS stent and not other types of drug-eluting stents, such as those that release sirolimus to inhibit tissue proliferation.

Dr. Stone said the results mean clinicians can have as much confidence recommending this stent for women as for men.

“The TAXUS paclitaxel-eluting stent safely reduces clinical and angiographic restenosis by approximately 70 percent compared to an otherwise excellent bare metal stent, and the results are similar in men and women. So for the types of lesions that were studied in the TAXUS-IV trial, this drug-eluting stent should be considered a new standard of care in women as well as in men. Further study, of course, is needed to look at other drug-eluting stents and the impact of gender,” he said.

Dr. Stone noted that some uncontrolled studies have indicated women were less likely than men to need a second procedure to re-open a block artery after stent placement. He said the difference between the results of those earlier studies and this one may be explained by the more rigorous, design of the TAXUS-IV trial, with its careful clinical follow-up and the use of independent committees to reconcile events, which should minimize bias in how clinicians choose to treat female and male patients from affecting the outcomes.

Dean J. Kereiakes, M.D., at the Lindner Center for Research & Education and the Ohio Heart Health Center in Cincinnati, Ohio, who along with colleagues wrote an editorial on TAXUS-IV trial reports appearing in the journal, also pointed out that the study design leaves some questions unanswered about whether there may be any gender-related differences in the rates of infrequent events.

“Based on review of the TAXUS-IV protocol, this appears to be a non-prespecified post-hoc subset analysis performed to test whether women shared the same restenosis reduction from the TAXUS stent as men. The analysis was underpowered to detect small differences, either by subset testing, or by a test of interaction, which was not done. Because this subset was determined to have similar outcomes as the overall randomized cohort, an estimation of the power to detect a given difference in treatment effect would help to put the findings into perspective. It is not clear if there was an expectation that women should receive a differential effect from drug-eluting stents, and if so, what difference might be expected. Acknowledging these limitations, the TAXUS stent appears to be associated with better clinical and angiographic outcomes than the comparator EXPRESS bare metal stent in women. Confirmation of these results in independent patient populations is required to understand the generalizability of the observations and their relevance to clinical practice,” Dr. Kereiakes said.

In addition to the Columbia University Medical Center and Cardiovascular Research Foundation, the authors of the TAXUS-IV gender analysis manuscript included researchers from Abbott Northwestern Hospital in Minneapolis, Minn.; St. Joseph’s Medical Center Towson in Towson, Md.; Research Associates of Jackson in Jackson, Tenn.; Huntsville Hospital in Huntsville, Ala., and the Cleveland Clinic Foundation in Cleveland, Ohio, as well as the sponsor Boston Scientific Corp. in Natick, Mass.

The American College of Cardiology, a 31,000-member nonprofit professional medical society and teaching institution, is dedicated to fostering optimal cardiovascular care and disease prevention through professional education, promotion of research, leadership in the development of standards and guidelines, and the formulation of health care policy.

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