The American Heart Association (AHA) and American College of Cardiology (ACC) released four new guidelines dealing with the prevention of cardiovascular disease (CVD) by better assessing risk and by managing cholesterol, lifestyle, and weight.
"These guidelines will provide updated guidance to primary care providers, nurses, pharmacists, and specialty medicine providers in how best to manage care of individuals at risk for cardiovascular diseases based upon evidence up through 2011," ACC president John Harold, MD, of Cedars-Sinai Heart Institute in Los Angeles, said on a conference call with reporters.
Assessment of Cardiovascular Disease Risk
One of the new guidelines describes a new equation for estimating a patient's risk of having an atherosclerotic cardiovascular disease event in the next 10 years based on pooled results from five large cohort studies. The equation considers age, sex, total and HDL cholesterol, systolic blood pressure, blood pressure treatment, diabetes, and smoking.
The new equation differs from previous ones in that it considers risk of stroke.
After performing the risk assessment using the new equation, some uncertainty might remain, and the members of the writing group listed additional factors that may be considered to help clarify the issue: family history of premature heart disease in a first-degree relative, high-sensitivity C-reactive protein, coronary artery calcium scoring, and ankle-brachial index.
The authors also concluded that a calculation of longer-term risks -- over the next 30 years or during the lifetime -- may be considered in younger patients ages 20 to 59 who do not have a high short-term risk but have a concerning risk factor burden.
Treatment of Blood Cholesterol
The guideline on managing blood cholesterol to reduce atherosclerotic cardiovascular risk diverges from previous guidance by moving away from hard treatment targets for LDL and non-HDL cholesterol. Instead, the focus is on identifying the appropriate intensity of therapy for a particular patient in order to reduce his or her risk in combination with a heart-healthy lifestyle, according to Neil Stone, MD, also of Northwestern University, who chaired the writing group for the cholesterol guidelines.
Although all of the lipid-lowering therapies were considered, Stone said, the strongest evidence of a favorable risk-benefit ratio existed for statins.
To simplify the incorporation of the guidance into clinical practice, he and his colleagues identified four groups of patients deemed to derive the most benefit from statin therapy:
- Those with a history of atherosclerotic cardiovascular disease
- Those with an LDL cholesterol level of 190 mg/dL or more, which includes many patients with familial hypercholesterolemia
- Patients with diabetes ages 40 to 75 who do not have a history of clinical atherosclerotic cardiovascular disease and have an LDL cholesterol level of 70 to 189 mg/dL
- Those with a 10-year cardiovascular risk -- assessed using the new equation -- of 7.5% or higher and an LDL cholesterol level of 70 to 189 mg/dL but no history of cardiovascular disease
High-intensity statin therapy -- that which reduces LDL cholesterol by at least 50% -- is indicated in the first two groups, Stone said.
For patients with diabetes, the new risk equation can be used to determine whether high-intensity of moderate-intensity statin therapy (that associated with LDL cholesterol reductions of 30% to 49%) should be used, he said.
Moderate-intensity statin therapy should be sufficient in the last group, he said. Recommendations are also provided for patients who do not fall within one of those four groups.
The importance of healthy dietary patterns is emphasized in the guideline on lifestyle management to reduce atherosclerotic cardiovascular disease risk, according to Robert Eckel, MD, of the University of Colorado at Denver, one of the co-chairs of the writing group for the lifestyle guidelines, which were focused on patients who would benefit from reductions in LDL cholesterol and blood pressure.
There is a strong recommendation to consume a diet rich in fruits, vegetables, whole grains, low-fat dairy, legumes, fish, poultry, and nuts and low in sweets, sugar-sweetened beverages, and red meats -- along the lines of the DASH or Mediterranean diets.
The writing group also found evidence backing restrictions on saturated fat and trans fat to reduce cholesterol levels, and restrictions on sodium to reduce blood pressure.
Physical activity is included as well, with the authors concluding that the evidence supports guidance released by the Department of Health and Human Services in 2008, which recommends 40 minutes of moderate-to-vigorous activity on 3 or 4 days a week.
Management of Overweight and Obesity
Maintenance of a healthy weight is the focus of the another guideline, which was produced in collaboration with the Obesity Society.
Donna Ryan, MD, of Pennington Biomedical Research Center in Baton Rouge, La., one of the co-chairs of the writing group for the obesity guidelines, said five critical questions were addressed.
She and her colleagues determined that body mass index should be used as a quick first evaluation, followed by a measurement of waist circumference, to determine risks of cardiovascular disease, diabetes, and death.
They looked into how much weight loss is needed to achieve health improvements and found that even modest weight loss -- 3% to 5% -- was associated with clinically meaningful benefits.
The guideline does not contain a preference for any specific diet to achieve that weight loss, but rather contains a recommendation for clinicians to prescribe diets designed to reduce caloric intake with modifications according to patient preferences and health status.
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