ACC/AHA GUIDELINES

Integrating New Cardiovascular Guidelines in Primary Care Practice: ACC/AHA Guidelines on the Treatment of Blood Cholesterol to Reduce Atherosclerotic Cardiovascular Risk in Adults

 

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I was looking forward to a “long winter’s nap” at the end of 2013, but I got some hot coals in my stocking courtesy of the American Heart Association, American College of Cardiology, and National Heart Lung and Blood Institute. My patients and my staff also heard the announcements on the national news: new guidelines on cholesterol, obesity, lifestyle recommendations, cardiovascular risk assessment, and hypertension. These guidelines were all released within a few days of one another followed almost immediately by confusion and controversy which is now receiving less attention in the lay press, but has left us at the mercy of the experts. There are literally hundreds of articles about these guidelines published in MEDLINE journals since their release and the discussions in the “gray literature” are TNTC (too numerous to count)!

You may know from my previous articles that I am a “guideline guy” and I have been wrestling with these new guidelines since they were announced. In this series of articles I will try to summarize the new guidelines and how our clinic, which sees low-income uninsured adults in whom cardiovascular risk management competes with other issues of daily subsistence, will be affected.

The American Heart Association released a new guideline on cholesterol management [1] in November, just in time to spoil my Thanksgiving dinner! There are several substantial differences between this guideline and the NHLBI Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (ATP3) which was last updated in 2004.[2,3] The most dramatic is a change from “treat to target” to “fire and forget.” In those patients for whom statin therapy is indicated, the guideline recommends a fixed dose based on the expected benefit noted in clinical trials rather than individual “titration.” Although this is a valid approach based on published evidence, I find it quite ironic in an era in which “personalized medicine” has become the watchword for the future of patient care.

The ACC/AHA guideline recommends “lifestyle modification” for primary prevention of atherosclerotic cardiovascular disease (ASCVD) in everyone. The only drug class recommended in this guideline is statins. It divides the statins into three categories: “high intensity” (HIS) expected to reduce LDL cholesterol (LDL-C) by 50% or more (e.g. rosuvustatin 20-40 mg and atorvastatin 40-80 mg.); “moderate intensity (MIS) expected to reduce LDL-C by 30-50% (e.g. atorvastatin 10-20 mg, rosuvastatin 5-10 mg, simvastatin 20–40 mg, pravastatin 40-80 mg, lovastatin 40 mg, fluvastatin XL 80 mg, fluvastatin 40 mg bid, and pitavastatin 2–4 mg); and “low intensity” (LIS) expected to reduce LDL-C by less than 30% (e.g. simvastatin 10 mg, pravastatin 10–20 mg, lovastatin 20 mg. fluvastatin 20–40 mg, and pitavastatin 1 mg).

Table 2 of the ACC/AHA guideline provides an algorithmic approach for adults (age 21 or older). [1] The approach first considers whether the individual has already been diagnosed with ASCVD. If so, the guideline recommends that a high intensity statin be prescribed unless the individual is either over age 75 or is “not a candidate” of HIS. Although the guideline does not specifically who should not be “a candidate”, it does recommend that non-candidates be prescribed MIS. The ACC/AHA expert panel made no recommendations regarding the initiation or discontinuation of statins in patients with New York Heart Association (NYHA) class II–IV ischemic systolic heart failure or in patients on maintenance hemodialysis.

If ASCVD is not manifest, but current LDL-C is greater than 189 mg/dL, the guideline recommends prescribing HIS with MIS recommended for individuals for whom the risk of adverse effects of HIS is significant. The guideline states that characteristics predisposing individuals to adverse effects of HIS include, but are not limited to: age over 75 years; multiple or serious comorbidities, including impaired renal or hepatic function; history of previous statin intolerance; muscle disorders; unexplained alanine aminotransferase (ALT) elevations greater than 3 times upper limit of normal; or concomitant use of drugs affecting statin metabolism. Additional characteristics that may modify the decision to use HIS may include, but are not limited to: history of hemorrhagic stroke and Asian ancestry.

If the LDL-C is less than 189 mg and without ASCVD or DM, a 10 year estimated risk for ASCVD using the ACC/AHA Pooled Cohort Equation (PCE) is recommended. [4] The PCE is available from the AHA as a free smartphone application (iOS and Android), a formula downloadable for spreadsheets like Microsoft Excel, or a website version accessible to both healthcare providers and the public with internet browsers. The PCE requires information on the individual’s gender, age, total and HDL cholesterol, race, systolic blood pressure, hypertension treatment status, smoking status, and diabetes status.

For diabetic adults aged 40-75 (either type 1 or 2 DM), if the PCE estimates a 10 year ASCVD risk less than 7.5%, the guideline recommends prescribing MIS. If the risk is estimated to be 7.5% or greater HIS is recommended. For individuals aged 40-75 without diagnosed ASCVD or DM and LDL between 70 mg and 189 mg, recommendations are based on the PCE; if the risk is 7.5% or higher, the guideline recommends either MIS or HIS based on the values of the component variables. For adults aged 21-39 or over 75 with ten year calculated ASCVD risk over 5%, the guideline states “it is reasonable to offer MIS”; if the risk is less than 5%, the guideline states “statin therapy for primary prevention may be considered after evaluating the potential for ASCVD risk reduction benefits, adverse effects, drug-drug interactions, and discussion of patient preferences.” Presumably if this low risk group is to be treated, they would be candidates for LIS although the guideline does not specifically address this.
The new ACCA/AHA guideline on cholesterol management is predicted to significantly increase the number of Americans receiving recommendations to take statin medication compared with recommendations of the ATP3 guidelines that have been the standard of care for the past decade.

The “treat to target” management of LDL recommended by the ATP will not likely yield immediately to the “fire and forget” model of statin therapy because both practitioners and patients currently consider treating to lipid goals to be “standard of care.” The ACC/AHA guideline does not address the management of lipid abnormalities in children or adolescents. The guideline states that statins are listed as pregnancy category X, and should not be used in women of childbearing potential unless these women are using effective contraception and are not nursing.

The ACC/AHA guideline has some significant ramifications for our practice. Our population is predominantly minorities which have been underrepresented in clinical trials; we are concerned that the PCE calculator may not estimate their ASCVD risk properly. The recommended HIS agents are more expensive than MIS agents which often get our patients to their ATP3 goal levels for LDL-C and are offered under the “3 month supply for $10” programs of many of our nearby chain pharmacies. There will be fewer visits to both laboratory and office for our patients which may be more convenient and less expensive for them, but fewer opportunities for us to reinforce and assess cardiovascular prevention as well as to observe possible adverse effects of therapy.

Charles Sneiderman, MD, PhD, DABFP
Medical Director, Culmore Clinic
Falls Church, VA

Published June 3, 2014

 

Biosketch

Charles Sneiderman, MD PhD, retired in 2010 after a 31-year career in medical informatics at the Lister Hill National Center for Biomedical Communications, National Library of Medicine, National Institutes of Health. His work included research and development in telemedicine, distance learning, and medical language and image processing. Since leaving federal service, he has developed a computerized clinical decision support system to assist primary healthcare practices in the recognition and management of post-traumatic stress syndromes with support from the NLM Disaster Information Management Research Center. Dr. Sneiderman received a B.S. with high honors from the University of Maryland in 1969, and M.D. and Ph.D. degrees from Duke University in 1975 and completed residency training in family medicine at the Medical University of South Carolina in 1979. He has authored numerous scientific reports, book chapters, and medical educational media. Dr. Sneiderman was a Clinical Assistant Professor of Family Practice at the Uniformed Services University of the Health Sciences and maintains certification by the American Board of Family Medicine. He has practiced family medicine part-time in the Washington, DC area since 1980. He has assisted wounded warriors with adaptive snow sports since 2005.

 


References:

  1. Stone NJ, Robinson J, Lichtenstein AH, et al. 2013 ACC/AHA Guideline on the Treatment of Blood Cholesterol to Reduce Atherosclerotic Cardiovascular Risk in Adults: A Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. Circulation. 2013 Nov 12. [Epub ahead of print].
  2. NIH. NHLBI. Third Report of the Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel III). http://www.nhlbi.nih.gov/guidelines/cholesterol/index.htm
  3. NIH. NHLBI. ATP III Update 2004: Implications of Recent Clinical Trials for the ATP III Guidelines. http://www.nhlbi.nih.gov/guidelines/cholesterol/atp3upd04.htm
  4.  American Heart Society and American College of Cardiology. 2013 Prevention Guideline Tools; CV Risk Calculator. http://my.americanheart.org/professional/StatementsGuidelines/PreventionGuidelines/Prevention-Guidelines_UCM_457698_SubHomePage.jsp