The feminine heart
Cardiovascular disease is an equal-opportunity killer
by Gregory P. Curnew, MD, and Katie Dalziel
Vol.17, No.09, October 2009

A 56-year-old woman showed signs of heart attack with raised troponin levels and was sent for an angiography that came back normal. She has hypertension and high cholesterol values (TC 6.38, TG 1.64, LDL 4.03, HDL 1.64, FBG 6.3). She’s not on statins, due to muscle pain side effects, but is on blood pressure medication.

Atherosclerosis is the leading cause of death in both sexes. Complications of vascular disease will kill about 37% of women and 35% of men. This is not a disease of the male gender, as once we thought. The major difference is that women usually present with symptoms of blocked arteries 10 years later than men. We’ve learned that women tend to present with more diffuse disease, so it’s important to distinguish a truly normal coronary angiogram from one that shows minor coronary artery disease with lesions in the order of 20-40% stenosis. These women are still at risk and need aggressive risk factor modification.

Of lipids and ladies

Women generally have lower LDL and higher HDL levels than men until menopause, which triggers a fall in HDL and a rise in LDL. JUPITER and the meta-analysis of lipid-lowering trials show a clear benefit from treating hyperlipidemia in our female population. The Heart Protection Study (HPS), using 40 mg of simvastatin in 20,000 individuals at high risk for atherosclerosis progression, clearly showed benefit and safety in both men and women. LDL cholesterol is still an important risk factor but it’s probably more atherogenic in men, while high triglycerides and low HDL cholesterol may be bigger factors in women. Diabetes, high C-reactive protein, physical activity and tobacco are also likely to be key variables in the female population.

The Women’s Health Study looked at 40,000 females and demonstrated that aspirin decreases the risk of stroke in those 55 years of age or greater with multiple cardiac risk factors and reduces both heart attacks and strokes in women aged 65 or greater in those free of vascular disease. More recent data suggests that while aspirin is of value in high-risk primary prevention, the risk of bleeds can’t be ignored. It’s far more effective and safer to lower blood pressure and lipids. Similarly, all women and men with established vascular disease should be on lifelong anti-platelet treatment. The bottom line is that females around the age of 50 should have a full lipid profile done and be treated according to the Canadian Consensus Guidelines. Those who have diabetes or vascular disease should be treated extremely aggressively.

What else we’ve learned

Since the landmark Women’s Health Initiative, hormone replacement therapy is no longer considered vascular-protective, and is now deemed a cardiovascular risk factor. Further research is necessary, as other data suggests that estrogens improve the health of the endothelium. But currently, hormone replacement therapy should be used only for significant menopausal complaints and should be regarded as harmful to the vascular system.

There’s wide agreement today that trans-fatty acids promote vascular disease. The Nurses’ Health Study suggested that every 5% increase in energy intake from saturated fats (as opposed to carbohydrates) brought a 17% increase in the risk of coronary artery disease. High intakes of monounsaturated and polyunsaturated fats were associated with a decreased risk — a reminder that not all fats are created equal.

The WISE trial attempted to shed light on the issue of women who have suggestive ischemia without findings of obstructive coronary artery disease upon angiography. It found that symptomatic women with apparently normal coronary arteries still had three times the event rate of asymptomatic women.

Ruthless disease

Another recent study, Raloxifene for Use of the Heart (RUTH), investigated the potential heart disease protection abilities of Raloxifene in over 10,000 postmenopausal women with a mean age of 67.5 years and coronary heart disease or multiple risk factors. After 5 years, it showed no benefit in heart disease prevention, and while it significantly reduced the risk of invasive breast cancer, this benefit was outweighed by a 50% increase in venous thromboembolism and fatal stroke.

Heart disease is the leading cause of death in our female population, it just occurs 10 years later. Lifestyle changes are a top priority in women as in men. This includes smoking cessation, daily exercise, weight reduction and eating a heart-healthy diet (with a special emphasis on salt restriction and increased fruit and vegetables). In addition to the significant risk carried by our 56-year-old-possible-heart-attack patient presented above, there’s an older generation in whom recurrent diastolic dysfunction with recurrent congestive heart failure is reaching epidemic proportions. Newer research will highlight better strategies. For now, we should focus on salt restriction, appropriate use of diuretics and aggressive control of hypertension.

Gregory P. Curnew, MD, FRCPC is Associate Professor at McMaster University in Hamilton, ON, and Director of the Coronary Care Unit at Hamilton General Hospital.

Katie Dalziel is a biochemistry graduate from Queens University, Kingston, ON.

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