JACC: As DES mature, do sex differences still exist?

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The unrestricted use of drug-eluting stents (DES) is associated with similar long-term safety and efficacy among women and men with coronary artery disease, according to a study in the March issue of the Journal of the American College of Cardiology: Cardiovascular Interventions. However, the accompanying editorialists wrote that “we are only at our infancy in our understanding of sex differences in cardiovascular disease.”

More than one million PCIs are performed each year in the U.S., with one-third of procedures performed in women. The study authors wrote that “the advent of DES has led to important reductions in restenosis and repeat revascularization rates compared with bare-metal stents, and DES are used in more than 80 percent of patients undergoing PCI in the U.S. However, sex-related differences in clinical and angiographic outcomes after revascularization with DES are not well established.”

Thus, in this study, Giulio G. Stefanini, MD, from the department of cardiology at Bern University Hospital in Bern, Switzerland, and colleagues sought to investigate sex-based differences in long-term clinical and angiographic outcomes after coronary revascularization with DES by pooling individual patient data from three all-comers randomized DES trials (SIRTAX, LEADERS and RESOLUTE All-Comers).

Of 5,011 patients, 97.5 percent completed two-year follow-up (1,164 women, 3,721 men). Protocol-mandated angiographic follow-up was available for 1,561 lesions (351 among women, 1,210 among men). In this analysis, the primary endpoint was a composite of cardiac death and MI at two years.

At baseline, women, as compared with men, were older, more frequently had diabetes, obesity and hypertension, less frequently had smoking habits, previous MI and previous surgical revascularization, and had a smaller reference diameter of the target vessel as well as a lower SYNTAX score.

After adjustment for baseline differences, the researchers found that women and men had a similar risk of cardiac death or MI, cardiac death and MI at two years. Similarly, risks of target lesion revascularization, target vessel revascularization and definite or probable stent thrombosis were comparable for women and men.

Also, they found follow-up angiography showed no differences in terms of in-stent late loss (0.18 mm vs. 0.20 mm) and in-segment binary restenosis (8.5 percent vs. 8.5 percent).

Stefanini and colleagues summarized their findings as follows:
  • Women undergoing PCI with the unrestricted use of DES differ from their male counterparts and are typically older, have more cardiovascular risk factors except for smoking and a lower degree of angiographic complexity as assessed by the SYNTAX score.
  • After controlling for baseline differences, women undergoing PCI with DES have a similar risk of cardiac death and MI as compared with men through two years of follow-up.
  • DES achieves equivalent safety and efficacy in women and men with similar results in terms of stent thrombosis, repeat revascularization and angiographic outcomes through two years of follow-up.

“The present study extends the available evidence to a large and homogenous cohort of women and men who were treated with the unrestricted use of DES in an all-comers patient population, including STEMI, and a high prevalence of ‘off-label’ indications,” study authors concluded. “The similar outcomes in terms of cardiac death, MI and stent thrombosis are reassuring and reinforce the lack of a sex gap in terms of patient and device safety.”  

“So, have we answered most of the questions with regard to cardiac differences between men and women? Not by a long shot,” wrote editorialists Cindy L. Grines, MD, and Theodore L. Schreiber, MD, of the Detroit Medical Center Cardiovascular Institute and Wayne State University School of Medicine. “There seems to be fundamental biological differences in vascular structure, function and atherosclerotic plaque between men and women. The mechanism of acute MI is different between the sexes, with women having a higher prevalence of Takotsubo infarctions, subendocardial MIs, spontaneous dissection and plaque erosion, compared with men.

“Vasospastic disorders, such as pulmonary hypertension, Reynaud's phenomena, migraines and coronary microvascular disease, occur more commonly in women,” the editorialists continued. “Clearly there are hormonal influences contributing to peripartum cardiomyopathy and spontaneous coronary dissection. Moreover, complications during pregnancy, such as gestational diabetes or preeclampsia are risk factors for future cardiac events in women.”

Grines and Schreiber concluded, “Although it is an incredible success that both women and men can now undergo PCI with similar benefits, elucidation of differences in the prevalence, mechanism, manifestation and treatment of cardiovascular disease will require more sex-specific investigations."