May 7, 2011 (Baltimore, Maryland) — The differences between cardiovascular disease in men and women is often underappreciated by interventionalists and, in many cases, not well understood because there are not enough women in clinical trials, according to experts speaking here at the Society for Cardiovascular Angiography and Interventions (SCAI) 2011 Scientific Sessions.

"We've applied our data to women and men and assumed that we'd get the same sort of outcome," Dr Jennifer Tremmel, who is clinical director of women's heart health at Stanford Hospital (Stanford University, CA), told heartwire . "We must understand that most of the data we have right now [on cardiac intervention in women are] just post hoc subanalyses [of trials that mostly enrolled men] and simply hypothesis generating. Having real prospective sex-difference studies moving forward will strengthen the field."

World Health Organization data show that cardiovascular disease causes 55% of deaths in women, but only 43% of deaths in men, and US National Health and Nutrition Examination Survey (NHANES) figures show the prevalence of MI increased in women aged 35 to 54 over the past 20 years while it declined in men of that age. However, on average, the care of women with acute cardiac events is inferior to that of men.

Women suffering an acute coronary syndrome generally have longer door-to-balloon times than men, and data from the American Heart Association's Get With the Guidelines database show that long door-to-balloon times are more likely to lead to poor outcomes in women than men, Tremmel said. When she examined the door-to-balloon data from her own center, she found the outliers were usually women. She advised all interventionalists to investigate their centers' data to see whether outcomes and door-to-balloon times for male and female patients are improving at the same rate. "Without looking, you don't know, because everyone will [assume] of course they are not [different]."

She also pointed out that women younger than 55 years have higher hospital mortality rates after acute MI than age-matched men, although that gap is closing and is not seen in older men and women, but added, "We really don't know why. This problem is the elephant in the room. It's something we all know, but nobody is really addressing it, and we don't know what to do about it, except that when we see a young woman come in we know her chances of surviving are less."

She hopes the VIRGO trial, sponsored by the National Heart, Lung, and Blood Institute, will help explain some of these discrepancies. The study will involve 2000 women and 1000 men hospitalized following a possible heart attack. It will collect a wide variety of data on symptoms, quality of life, and medical care, including blood samples, with one-month and one-year follow-up.

Women are also more likely to suffer bleeding complications during PCI. Early evidence suggests that switching to the transradial approach will reduce these risks. To see how the transradial approach can help women in particular, the Duke Clinical Research Center is planning to conduct the Study of Access Site for Enhancing PCI (SAFE-PCI) in Women trial, which will investigate transradial or transfemoral PCI in women only.

Enrolling More Women in Trials

The SAFE-PCI in Women study is the sort of women-only trial that is challenging to enroll, but also "the only way we're going to get to the bottom of some of these issues," Dr Cindy Grines (Beaumont Hospital, Royal Oak, MI) argued during the same session at the SCAI meeting. Grines presented data showing that although federal rules mandate that all trials sponsored by the National Institutes of Health track gender-specific outcomes, only about a quarter of them do, and the US Food and Drug Administration (FDA) frequently approves new cardiovascular devices based on trials that do not investigate possible gender differences. Grines cited survey data showing that women are more reluctant to participate in trials, often because of concerns about the risks of the investigational treatment, but also because trial participation can be too time-consuming. "As clinical researchers, it's up to us to sell the research to women and not downplay the side effects, but put it in perspective, that it's not quite as bad as they might think. And you've got to think outside the box with regard to providing more flexible visits, providing visiting nurses, or providing transportation or even financial incentives."

To recruit more female study subjects, Grines advocates loosening some of the exclusion criteria, such as age limits and restrictions on women of childbearing age in some trials, while also working with the FDA to make trial protocols more subject-friendly without undermining their purpose. "We're our own worst enemies--and the FDA is part of this--but there are way too many follow-up visits and way too many blood tests for every single trial that we do," she said. "[For example,] why do [participants] have to come in for an ECG? Why can't they just go to their own doctor's office? It's kind of ridiculous how stringent these things often are."

Tremmel emphasized the urgent need for public-awareness campaigns aimed at women to increase trial enrollment. "The lay public probably doesn't understand the importance of research. It would be a challenging message [to promote], but one that could make a difference," she said. "I've noticed that if I can sit with them long enough and say 'understanding women is very important,' they start to get that concept, and women in general want to have this improved."

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