Physicians need a management strategy to help patients at risk of atherosclerotic cardiovascular disease. Here is an example of how new lipid recommendations can guide care.
A 55-year-old South Asian Indian physician comes to you for management recommendations for primary prevention of atherosclerotic cardiovascular disease (ASCVD). He has no current cardiovascular symptoms.
He has an eight-year history of well-controlled arterial hypertension, for which he has been treated with lisinopril 10 mg daily. He is a nonsmoker, has no history of diabetes and has never taken treatment for a lipid disorder. His father had an MI at age 52.
He reports that although his dietary adherence “could be better,” he generally follows a low-fat diet, and walks on a treadmill for 30 minutes three times per week. On examination, he has a waist circumference of 35 inches, body mass index 26 kg/m2, blood pressure 126/62 mm Hg and the remainder of his exam is normal.
His lipid profile shows a total cholesterol 200, high-density lipoprotein cholesterol (HDL-C) 45, triglycerides 200, low-density lipoprotein cholesterol (LDL-C) 122 and non-HDL-C 155 mg/dL. His comprehensive metabolic panel, thyroid stimulating hormone (TSH) and urinalysis are normal.
He requests evidence-based treatment for ASCVD prevention. You tell him that there are two new evidence-based cholesterol guidelines: the 2013 American College of Cardiology/American Heart Association (ACC/AHA) Guideline on the Treatment of Blood Cholesterol and the 2014 National Lipid Association (NLA) Recommendations for the Patient-Centered Management of Dyslipidemia, which share similarities in cholesterol management, but also have some important differences.
Both the ACC/AHA and NLA approaches recommend moderate or high-intensity statin therapy in patients with established ASCVD, those with genetic dyslipidemias (untreated LDL-C of 190 mg/dL or more), and those with diabetes mellitus. But then a divergent approach to preventive care begins.
Some of the most important differences are in the following areas:
1. Evidence base for recommendations: The ACC/AHA approach uses exclusively randomized controlled trials (RCT) or meta-analyses of statin trials. The NLA approach advocates the use of RCT or meta-analyses of these same statin trials, but also includes information contributed from non-statin trials, observational epidemiologic data, genetic, metabolic and mechanistic studies. This approach emphasizes the “totality” of all evidence instead of “limited” evidence from statin RCT.
2. Lipid goals: The ACC and AHA do not recommend the employment of lipid goals in patient care, but instead focus on the dose of statin prescribed as a performance measure for clinicians. They advise against the use of non-statin lipid therapy.
The NLA perspective is that excessive circulating cholesterol-carrying lipoproteins (as measured by non-HDL cholesterol [total minus HDL cholesterol] and LDL cholesterol) is a root cause of ASCVD and that specific goals for these lipoproteins should be targeted. While lifestyle intervention plus evidence-based statin therapy is the first choice in preventive drug therapy, non-statin options play an important additive role when lipid goals are not achieved or when patients are statin intolerant.
The employment of lipid goals is one method of enhancing provider-patient partnership to achieve long-term adherence to preventive recommendations. Emphasis on reduction of blood lipids and achievement of lipid-related goals, rather than on specific doses of drug therapy, helps to draw the attention of the patient to the basic cause of ASCVD and helps them to focus on improving their lipids through lifestyle and drug therapy.
3. Risk assessment: The ACC and AHA recommend that untreated primary prevention Caucasian and African-American patients between the ages of 40 and 79 who do not fall into one of four statin benefit groups should have their 10-year ASCVD risk assessed using the Pooled Cohort Risk calculator available through the ACC website. Those whose 10-year risk is 7.5 percent or more are advised to engage in a discussion with their provider about the value of starting statin therapy.
The NLA is concerned about the validation of this 10-year risk calculator, its potential to overestimate risk and its potential to promote the use of statin therapy in certain populations in whom benefit is uncertain. For example, the application of the Pooled Cohort Risk Calculator to a European population, mean age 65 years, suggested that 96 percent of men and 66 percent of women would be candidates for statin therapy.
The NLA approach recommends risk factor counting as an established means of assessing ASCVD risk. In those whose risk is assessed as “intermediate” based upon risk factor counting, the use of any of three readily available risk calculators, in accordance with that patient’s specific characteristics, is recommended as a reasonable option, depending upon the provider’s clinical judgment.
4. Complex lipid disorders, including high triglycerides and the metabolic syndrome: The ACC/AHA document makes no comments about the management of hypertriglyceridemia with values between 200 and 500 mg/dL or about the metabolic syndrome. The NLA approach provides specific advice regarding the importance of lifestyle intervention as a first step in the management of both of these disorders, and then advocates, if necessary, pharmacologic approaches, as patients with triglyceride elevations in this range, with or without the metabolic syndrome, are at increased risk for future ASCVD events.
Returning to our patient, he asked which approach would be most appropriate for his care. He was told by his clinician that his South Asian ethnicity, which is associated with a higher risk of ASCVD than either Caucasian or African-American populations, is not accounted for in the ACC/AHA approach, and his calculated 10-year ASCVD risk of 7 percent using the Pooled Cohort Risk Calculator is likely an underestimate of his risk.
In addition, the management of hypertriglyceridemia for ASCVD prevention is not addressed in the ACC/AHA guideline. His provider, therefore, chose the NLA approach to lipid management. It includes the use of lifestyle modification and predominantly statin therapy to reduce all of the patient’s atherogenic lipoproteins in a patient-centered manner, taking into account his ethnicity, family history and desire to be treated according to the best available evidence.
He had three major risk factors (age, treatment for hypertension and family history of premature coronary heart disease). Based on this information, he was considered a high-risk patient and non-HDL cholesterol and LDL cholesterol goals of less than 130 and less than 100 mg/dL were set. Clinicians arranged a consultation with a registered dietitian, advised him to increase his cardiorespiratory program to a minimum of 150 minutes per week and scheduled a follow-up visit in three months to assess his progress toward his lipid goals.
Dr. Orringer is director of the preventive cardiovascular medicine program at the University of Miami Health System and is a co-author of the NLA recommendations. He is a fellow of the ACC and the NLA, where he is president-elect.