PREVENTIVE CARDIOLOGY suppl 2 • Fall 200726

This supplement has presented an overview of the evidence-based guidelines published

by the American Heart Association (AHA) in 2007 for the primary prevention of cardiovas-cular disease (CVD) in women.1 Two important changes from the 2004 guidelines2 include (1) risk assessment and (2) the role of aspirin in pre-ventive therapy. First, the 2007 update provides a scheme for a general approach to the female patient that classifies her as being at high risk, at risk, or at optimal risk. This classification scheme allows for alignment of the guidelines with the clinical trial evidence. In updating the new guide-lines, the expert panel also recognized limita-tions of risk stratification using the Framingham risk score. Although a Framingham risk score >20% could be used to identify a woman at high risk, a lower score is not sufficient to ensure that a woman is at low risk for CVD. Even the pres-ence of 1 risk factor in a woman aged 50 years is associated with an increased risk of CVD and lower survival.3

Second, aspirin therapy should be considered in all women for stroke prevention, depending on whether the benefits outweigh the risks of bleeding. Women at high risk should take aspirin (75–325 mg/d) unless contraindicated (class I recommendation). In other at-risk or in healthy women aged 65 years or older, aspirin (81 mg/d or 100 mg every other day) should be taken if blood pressure is controlled and the benefit of ischemic stroke and myocardial infarction (MI)

prevention outweighs the risk of gastrointesti-nal bleeding and hemorrhagic stroke (class IIa recommendation). In women younger than 65 years, taking aspirin does not appear to carry a benefit in heart disease protection. There may be a small benefit to taking aspirin for ischemic stroke prevention, but the expert panel decided that the data were not suggestive enough to give this a strong recommendation.1

Since the 2004 guidelines, additional infor-mation about the use of aspirin in primary prevention has been provided by a sex-specific meta-analysis of the 3 major primary prevention trials that included women.4 This meta-analysis further demonstrated a differential beneficial effect of aspirin according to sex: for men, the primary benefit was a reduction in MI, whereas for women, the major benefit was a reduction in stroke. The Women’s Health Initiative, the first primary prevention trial of aspirin specific to women, also showed that aspirin decreased the risk of stroke without affecting the risk of MI or vascular death in women.5 In this subgroup, there was a 26% risk reduction for major cardiovascu-lar events, which was statistically significant, and a 30% reduction in risk of ischemic stroke. Moreover, this was the only subgroup in which aspirin significantly reduced the risk of MI.

These data raised the question of whether aspi-rin should be given to all women older than 65 years for the prevention of stroke. This became a controversial issue in preventive cardiology, one which was the subject of a debate held at the American Society of Preventive Cardiology’s annual meeting in Phoenix, Arizona, in 2004. Both sides of the debate are presented in this supplement, with Dr Hsai proposing that aspirin should be used in this select subgroup of women and Dr Buring opposing this view.

According to Dr Hsia, stroke prevention is important for older women because stroke is very prevalent in this age group. From her

Does an Aspirin a Day Really Keep a Stroke Away?Lori Mosca, MD, MPH, PhD

SummARY

From the Department of Preventive Cardiology, New York-Presbyterian Hospital, New York, NYAddress for correspondence: Lori Mosca, MD, MPH, PhD, Director, Preventive Cardiology, Columbia University Medical Center, 601 West 168th Street, Suite 43, New York, NY 10032E-mail: ljm10@columbia.edu

www.lejacq.com ID: 7302

Preventive Cardiology® (ISSN 1520-037X) is published quarterly (Jan., April, July, Oct.) by Le Jacq, a Blackwell Publishing imprint, located at Three Enterprise Drive, Suite 401, Shelton, CT 06484. Copyright ©2007 by Le Jacq. All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopy, recording, or any information storage and retrieval system, without permission in writing from the publishers. The opinions and ideas expressed in this publication are those of the authors and do not necessarily reflect those of the Editors or Publisher. For copies in excess of 25 or for commercial purposes, please contact Ben Harkinson at BHarkinson@bos.blackwellpublishing.com or 781-388-8511.

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suppl 2 • Fall 2007 PREVENTIVE CARDIOLOGY 27

perspective, the results of the Women’s Health Initiative clearly favor the use of aspirin in women aged 65 years or older. Aspirin use resulted in a statistically significant reduction in risk of stroke in this patient subgroup, which translates into the prevention of 5 strokes per 10,000 woman-years of treatment. The risks of aspirin treatment were minimal; there were 2.3 major bleeding events per 10,000 woman-years (50% were intracere-bral hemorrhage and 1.8 were gastrointestinal bleeds requiring transfusion). Dr Hsia argued that the benefits of low-dose aspirin in the pre-vention of stroke in women aged 65 years or older outweigh the risks of serious bleeding.

In contrast, Dr Buring suggested that data from the Women’s Health Study did not show a huge benefit with aspirin therapy in this age group (there were 44 fewer cardiovascular events, but 16 more gastrointestinal bleeds requiring trans-fusion in addition to hemorrhagic events). For secondary prevention, the data show that the benefits greatly exceed the risks. For primary prevention, however, there is a smaller benefit with the same amount of risk (80 vs 19 benefit in secondary vs primary prevention; 5 vs 2.3 for risks in secondary vs primary prevention). She believes that aspirin should not be used for pri-mary prevention in women older than 65 years because there is not enough evidence to support this recommendation.

The Women’s Health Study was published in 2005. The debate was held because the trial looked at women older and younger than 65 years who had a CVD risk range from low to intermediate risk, so the guidelines and trial were not in agreement. The Women’s Health Initiative provided the much-needed data to support the new recommendations for stroke prevention in women aged 65 years or older. Data presented during the debate were critical in the develop-ment of the current guidelines, which now place women into 3 categories of risk: at high risk, at risk, and at optimal risk. The guidelines provide a framework for stratifying women into one of these risk categories so that physicians can set goals for patients to reduce their CVD risk.

Despite the guidelines, lack of awareness of heart disease risk remains a potential barrier to

preventive action. Confusion in the media also plays a role in misperceptions about effective CVD prevention strategies. Physicians must con-tinue to take the lead in discussing heart disease with their female patients, keeping in mind eth-nic disparities in understanding heart disease and stroke. With improved communication skills and patient education, improved awareness of risks for CVD disease and the guidelines should moti-vate women to adopt a heart-healthy lifestyle. Public policy interventions should further reduce the global burden of heart disease in all women.

Future directions will be determined by stud-ies of the impact of these guidelines on the pre-vention of CVD risk factors and burden of CVD, as well as controlled clinical trials of prevention strategies in a large number of women. Other research priorities include the development of effective methods to implement the guidelines in health care settings, the workplace, and com-munities. Communication of CVD risk and bar-riers to CVD prevention should be studied to develop creative methods that can be used to disseminate and implement the guidelines among diverse patient populations. Finally, the role of genetics in risk stratification and sex disparities in responses to preventive interventions is an important area of future research.

RefeRences

1 Mosca L, Banka CL, Benjamin EJ, et al, for the Expert Panel/Writing Group. AHA Guidelines. Evidence-based guidelines for cardiovascular disease preven-tion in women: 2007 update [published correction appears in Circulation. 2007;115(15):e407]. Circulation. 2007;115(11):1481–1501.

2 Mosca L, Appel LJ, Benjamin EJ, et al, for the American Heart Association. Evidence-based guidelines for car-diovascular disease prevention in women. Circulation. 2004;109(5):672–693.

3 Lloyd-Jones DM, Leip EP, Larson MG, et al. Prediction of lifetime risk for cardiovascular disease by risk factor burden at 50 years of age. Circulation. 2006;113(6):791–798.

4 Berger JS, Roncaglioni MC, Avanzini F, et al. Aspirin for the primary prevention of cardiovascular events in women and men: a sex-specific meta-analysis of random-ized controlled trials. JAMA. 2006;295(3):306–313.

5 Ridker PM, Cook NR, Lee IM, et al. A randomized trial of low-dose aspirin in the primary prevention of cardiovascular disease in women. N Engl J Med. 2005; 352(13):1293–1304.

Preventive Cardiology® (ISSN 1520-037X) is published quarterly (Jan., April, July, Oct.) by Le Jacq, a Blackwell Publishing imprint, located at Three Enterprise Drive, Suite 401, Shelton, CT 06484. Copyright ©2007 by Le Jacq. All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopy, recording, or any information storage and retrieval system, without permission in writing from the publishers. The opinions and ideas expressed in this publication are those of the authors and do not necessarily reflect those of the Editors or Publisher. For copies in excess of 25 or for commercial purposes, please contact Ben Harkinson at BHarkinson@bos.blackwellpublishing.com or 781-388-8511.

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