Preventing MIs and strokes in women
The new guidelines for preventing female heart disease contain some significant changes from the recommendations made just three years ago.
The American Heart Association’s new CVD-prevention guidelines for women view heart disease as a lifelong danger of varying intensity and take a long-term approach to prevention. The guidelines are designed to help clinicians customize preventive options for each patient. “The concept of cardiovascular disease as a ‘have-or-have-not’ condition has been replaced with the idea that CVD develops over time, and every woman is somewhere on the continuum,” says Lori Mosca, MD, MPH, PhD, director of preventive cardiology at New York-Presbyterian Hospital/Columbia Medical Center in New York City. Dr. Mosca chaired the panel that wrote the recommendations.
The new focus away from short-term risk “is very much needed for women—and men,” observes C. Noel Bairey Merz, MD, medical director of the Women’s Health Program and the Preventive and Rehabilitative Cardiac Center at Cedars-Sinai Medical Center in Los Angeles.
One change, Dr. Mosca said, is that “providers should not use menopausal therapies—hormone replacement or selective estrogen receptor modulators (SERMs), such as raloxifene or tamoxifene—to prevent CVD. They have been shown ineffective in protecting the heart and may increase the risk of stroke.”
Another change: The 2004 guidelines recommended folic-acid supplements as a possible preventive tool for some high-risk women. The update says the therapy is useless. “Recent studies have shown that folic acid is ineffective despite widespread use by patients and physicians hoping for a heart benefit,” Dr. Mosca says. “These findings emphasize the importance of using well-conducted clinical trial data to develop national recommendations to help patients and [clinicians] use best practices to prevent heart disease—practices based on data rather than myth or wishful thinking.” Similarly, the new guidelines also recommend against antioxidant supplements (such as vitamin E, C and beta-carotene) as having no preventive value.
CVD: leading cause of female mortality
CVD kills about 500,000 women each year. It ranks as the No. 1 cause of death among women, accounting for 38% of all female deaths, according to AHA statistics. Some 42.1 million women in the United States have been diagnosed with CVD. Specific recommendations for women are necessary, says Dr. Bairey Merz, because gender differences have become apparent in cardiology. Some of the differences have resulted in “sizable gender gaps in treatment that are adverse to women.” These include “a lower use of such medications as aspirin, beta blocker, statins, and ACE inhibitors in women who have heart disease compared with men, and a higher mortality rate among women after a heart attack.”
The guidelines are categorized based on the strength of the recommendation for each level of risk. Class I includes the most strongly recommended interventions, such as a healthy diet, exercise, and smoking cessation. Class III indicates an intervention is either not useful or possibly harmful, or both.
“The Class III category is important, especially in areas where there has been a lot of confusion, such as hormone therapy and antioxidant supplements.” Dr. Mosca said. “Research has shown these interventions have no benefit for preventing CVD in women.”
Some recommendations apply to all women:
• Eat fruits, vegetables, and high-fiber foods while limiting saturated fats to 7%-10% of total calories and avoiding added salt. Eat oily fish at least twice a week.
• Exercise for 60-90 minutes, preferably every day, if you need to lose weight or maintain a weight loss.
• Use nicotine replacement products and get counseling if you need help to quit smoking.
Dr. Bairey Merz, who was a reviewer for the new guidelines, said the diet recommendations were among the most significant advice, “shifting to Mediterranean eating, with less saturated fat and more nuts, beans, and fish.”
Other guidelines peg treatment to the amount of risk a woman faces for a heart attack within 10 years, based on the Framingham risk score and other factors. Low risk means a woman has a <10% chance of having a heart attack in 10 years; intermediate risk is a 10%-20% chance; and high risk is a >20% chance. According to Dr. Mosca, “This provides a very individual approach to preventing CVD throughout the population.”
How risk levels work in practice
The guidelines for aspirin therapy illustrate how risk levels work. Doses as high as 325 mg per day are recommended for high-risk women, as well as for women who actually have CVD. “Baby aspirin” doses of 81 mg per day are an option for women at intermediate risk, if their BP is controlled and if they are unlikely to suffer side effects, such as GI bleeding or hemorrhagic stroke. Enteric coating can protect against GI complications. Aspirin therapy is not recommended for healthy women at low risk.
The new guidelines recommend LDL levels <70 mg/dL for women at very high risk. High-risk women with LDL levels <100 are advised to take cholesterol-lowering drugs, preferably statins. Previous guidelines did not recommend routine statin therapy for these women, but recent studies have shown they are beneficial.
Stroke-prevention guidelines recommend warfarin for women with atrial fibrillation and those at intermediate or high risk for embolic stroke. Low-risk women and those who cannot tolerate warfarin should take aspirin.
ACE inhibitors and beta blockers were also recommended for all high-risk women who have hypertension.
“Overwhelming evidence suggests that CVD can be prevented in both women and men,” says Dr. Mosca. “These recommendations should help health-care providers and the public avoid initial or recurrent heart attacks and strokes.” Called Evidence-Based Guidelines for Cardiovascular Disease Prevention in Women: 2007 Update, the recommendations are available at the Web site of the journal Circulation (www.circ.ahajournals.org/cgi/content/full/115/11/1481. Accessed May 17, 2007). Eleven professional and government organizations, in addition to the AHA, participated in their formulation. The previous guidelines were issued three years ago.