It has been more than a decade since hypertension was classified as blood pressure higher than 140/90mmHg, but the new guidelines published by the American College of Cardiology (ACC) and the American Heart Association (AHA), in collaboration with nine other organizations, have redefined the hypertension era.1,2 Released at the American Heart Association (AHA) 2017 Scientific Sessions, the Journal of the American College of Cardiology,1 and Hypertension,2 the new guidelines have reshaped the management paradigm for hypertensive patients, targeting a lower blood pressure to further reduce their cardiovascular risks.
The evolving definition of hypertension
Management of hypertension is an extremely intricate conundrum as it is often complicated with diversified comorbidities such as cerebrovascular diseases, diabetes mellitus, or aortic diseases. Synthesizing the available scientific evidence at that time, the Joint National Committee (JNC) published a JNC report in 2003 (JNC7) to offer guidance to primary care clinicians, defining 140/90mmHg as the threshold of hypertension.3 For the next JNC report (JNC8) published in 2014, the definition of hypertension remained, but the threshold for treatment was adjusted to 150/90mmHg for patients aged ≥60 years without diabetes or chronic kidney disease.4
However, increasing evidence has suggested that blood pressure lower than the recommended level can further reduce the risk of death and cardiovascular events, with the most remarkable evidence coming from the SPRINT trial.5 This large-scaled (n=9,361), randomized study, which was funded by the National Institutes of Health (NIH), assigned patients at high risk for cardiovascular events (without diabetes) to two systolic blood pressure targets (120 and 140mmHg). Intriguingly, after 1 year, patients with the lower blood pressure target had lower rates of major cardiovascular event and death from any cause.5
2017 ACC/AHA guidelines: Reclassification of hypertension
I: Removal of prehypertension
The comparison of the definitions of hypertension between the JNC7 and the new 2017 ACC/AHA guidelines has been summarized in Table 1.1,3 While the definition of normal blood pressure remains unchanged, the new guidelines abolished the term “prehypertension”, and reclassified that range of blood pressure as “elevated blood pressure” or “stage 1 hypertension”. Dr. Paul Whelton, the chair of the 2017 ACC/AHA guidelines, explained that “because we felt at that stage somebody is already at substantial increased risk — double the risk for a heart attack compared with somebody in a normal blood-pressure range — so we think stage 1 hypertension is the appropriate term, and that will capture the risk for adults and for clinicians much better.”6
II: Reduction of hypertension threshold
As shown in Table 1, another major change is the definition of stage 1 hypertension, from 140/90mmHg to a more stringent 130/80mmHg. Dr. Whelton explained the rationale for the more intensive goal of blood pressure even in older adults, “it’s largely based on the fact that a large number of older adults have been enrolled in bloodpressure–lowering treatment trials, especially in the more recent trials.”6 Of note, in the SPRINT and ACCORD trials, antihypertensive treatment reduced the morbidity and mortality of cardiovascular disease, without any increased risk for orthostatic hypotension or falls.6
Impact of the 2017 ACC/AHA hypertension guidelines
Undoubtedly, a tremendous challenge for clinicians will be to translate the 2017 ACC/AHA guidelines into clinical practice, since more patients would be classified as being hypertensive. To extrapolate the theoretical influence brought by the 2017 ACC/AHA guidelines, a retrospective analysis based on US population (n=9,242) was conducted and published together with the new guidelines. “Compared with the JNC7 guideline, the 2017 ACC/AHA guidelines result in a substantial increase in the prevalence of hypertension,” pinpointed Dr. Paul Muntner from the University of Birmingham, Alabama, who was also the first author of the analysis.6 With the new guidelines, 13.7% more US patients would be classified as hypertensive (45.6% vs. 31.9%), leading to 31.1 million more hypertensive patients.7
Therefore, it is also reasonable to anticipate the escalation of antihypertensive medications use. Yet, the aforementioned analysis showed that the increment would only be 1.9% (36.2% vs. 34.3%),7 mostly due to the revised treatment recommendation. In the new guidelines, the treatment for stage 1 hypertension is determined by the underlying cardiovascular risk of the patients: only those with clinical cardiovascular disease of ≥10% estimated risk of atherosclerotic cardiovascular disease (ASCVD) would be offered treatment, while the remaining patients would be offered nonpharmacological interventions including weight loss, heart-healthy diet, increasing physical activities, etc.1 The vice-chair of the guideline committee, Dr. Robert M Carey, discussed the emphasis of the lifestyle. “Lifestyle modification is the cornerstone of the treatment of hypertension, and we expect that this guideline will cause our society and our physician community to really pay attention much more to lifestyle recommendations.”6
Hypertension definition: Can there be a consensus?
It is important to note that several differences exist between hypertension guidelines. When JNC8 was first published 4 years earlier, the American Society of Hypertension (ASH) and ACC/AHA also released their own clinical practice guidelines or advisory documents with numerous differences, hinting at an enormous discord among cardiology experts.8
Dr. Mary Walsh, president of the ACC, mentioned that “other groups have published high blood-pressure recommendations in the past 4 years, but they were not comprehensive, and they were not endorsed widely. These guidelines [ACC/AHA 2017] have been a collaborative effort by 11 organizations,” [the list of organizations is shown in Table 2].6
Dr. Stephen Hauser, the former president of the AHA, further elaborated. “We saw the need to update these guidelines to reflect the real threats of high blood pressure and establish a protocol that could improve the cardiovascular health of all Americans.” 6
Other expert organizations may not agree with the new guidelines
The American Academy of Family Physicians (AAFP), which was not involved in the development of the newly released guidelines, continues to endorse the JNC8. Dr. Jennifer Frost, the medical director for the AAFP Health of the Public and Science Division, believed that “current evidence doesn’t support an absolute threshold for initiating treatment, whether 130/80mmHg or 140/90mmHg, because there’s a continuum of risk.”9
“The greatest benefit comes from treatment of very high blood pressures and for those with high cardiovascular risk,” Dr. Frost mentioned. “As blood pressures get lower, the benefit of treatment gets smaller. This guideline [ACC/AHA 2017] moves the threshold down the continuum, which may benefit some individuals, but may also lead to unnecessary treatment and associated harms.”9
Dr. Frost pointed out that family physicians should approach hypertension treatment on an individualized basis, taking into account patients’ histories, risk factors, preferences, and resources. The decision to intensify blood pressure treatment “should be based on an informed discussion with patients, with a consideration of potential benefits and harms,” she noted.9
A living document to assist the clinicians
Dr. Whelton concluded that “this [2017 ACC/AHA guidelines] is a living document. We will modify it. I think one area that has come up already at this meeting is in regard to the use of risk calculators to predict events. They work well for somebody in my age range, but they’re not so useful in younger people, in the 20-40 years age range. For younger people, we need to look at lifetime risk. We’ll probably have to adapt the guidelines for that.”10 Dr. Whelton also hoped that the guidelines “will improve cardiovascular health. That’s the mission of the 11 organizations that supported the development of this guideline.”10
1. Whelton PK, Carey RM, Aronow WS, et al. 2017 ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA Guideline for the Prevention, Detection, Evaluation, and Management of High Blood Pressure in Adults: Executive Summary: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines. J am Coll Cardiol. 2017 [Epub ahead of print].
2. Whelton PK, Carey RM, Aronow WS, et al. 2017 ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA Guideline for the Prevention, Detection, Evaluation, and Management of High Blood Pressure in Adults: Executive Summary: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines. Hypertension. 2017 [Epub ahead of print].
3. Chobanian AV, Bakris GL, Black HR, et al. The Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure: the JNC 7 report. JAMA. 2003;289(19):2560-2572.
4. James PA, Oparil S, Cushman WC, et al. 2014 evidence-based guideline for the management of high blood pressure in adults: report from the panel members appointed to the Eighth Joint National Committee (JNC 8). JAMA. 2014;311(5):507-520.
5. Wright JT Jr., Williamson JD, Whelton PK, et al. A Randomized Trial of Intensive versus Standard Blood-Pressire Control. N Engl J Med. 2015;373(22):2103-2116.
6. New ACC/AHA Hypertension Guidelines Make 130 the New 140. Medscape. 2017. (Accessed December 15 2017, at https://www.medscape.com/viewarticle/888560)
7. Muntner M, Carey RM, Gidding S, et al. Potential U.S. Population Impact of the 2017 American College of Cardiology/American Heart Association High Blood Pressure Guideline. Circulation. 2017 [Epub ahead of print]
8. ASH/ISH Issue Separate Hypertension Guidelines From JNC 8, Hinting at Discord Medscape. 2013. (Accessed December 15 2017, at https://www.medscape.com/viewarticle/818080)
9. AAFP to Review AHA/ACC Redefinition of High Blood Pressure. AAFP. 2017. (Accessed December 15 2017, at https://www.aafp.org/news/health-of-the-public/20171115ahaacchbpguideline.html)
10. New Goals and Guidelines for Hypertension. Medscape. 2017. (Accessed December 15 2017, at https://www.medscape.com/viewarticle/888617)