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.
The guidelines were initially commissioned by the National Heart, Lung, and Blood Institute in 2008, and the ACC and AHA were brought in earlier this year to facilitate completion and publication of the documents, which were published online Tuesday in the Journal of the American College of Cardiology andCirculation: Journal of the American Heart Association.
THE goal of both the ACC and the AHA is to prevent cardiovascular diseases and improve the care of people living with or at risk of these diseases.
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.
“Previous equations predicted just the risks for having a coronary heart disease event,” Lloyd-Jones told reporters, “but we realized quickly that we were leaving a lot of risk on the table by not also including stroke in our risk assessment algorithm.”
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:
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.
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.
Strong recommendations are made regarding lifestyle interventions to help achieve weight loss, including at least 6 months of counseling regarding diet and exercise. The strongest recommendation was for a comprehensive program that includes on-site, intense interventions delivered by a healthcare professional trained in weight management.
And finally, the authors concluded that bariatric surgery may be an appropriate option in patients with a BMI of 35 kg/m2 or higher accompanied by obesity-related comorbidities, or with a BMI of 40 kg/m2 or higher regardless of comorbidities.
From the American Heart Association: