2017 ACC/AHA hypertension guidelines: Toward tighter control
Risk-based approach to hypertension management
The algorithm for hypertension management now incorporates objective assessment of cardiovascular risk. Specifically, it calls for estimation of the 10-year risk of atherosclerotic cardiovascular disease, defined as coronary heart disease death, nonfatal myocardial infarction, or fatal or nonfatal stroke.
The information required to estimate risk includes age, sex, race, total cholesterol, high-density lipoprotein cholesterol, systolic blood pressure, use of blood pressure-lowering medication, diabetes status, and smoking status. The guideline recommends an easy-to-use online risk calculator (https://tools.acc.org/ASCVD-Risk-Estimator).
A 10-year risk of 10% or more is designated as the cutoff between high risk and low risk. However, this is not based on trial evidence, and the risk calculator has not been verified in prospective trials to show that its use reduces cardiovascular events. The SPRINT trial,2 which was a study of blood pressure-lowering in high-risk patients, used a 10-year risk of 15% or more based on the Framingham risk score to delineate high risk.
Additionally, the 10-year risk calculator is valid only in patients ages 40 through 79, and some studies indicate that it may overestimate risk in older adults.14,15 This overestimation may lead to patients being started on pharmacologic therapy when it may not truly be indicated. The risk calculator controversy has been discussed in a previous issue of this journal.16
Blood pressure goals
Strong recommendation for known cardiovascular disease or atherosclerotic cardiovascular disease risk 10% or greater, weak recommendation for risk less than 10%, based on moderate-quality evidence for systolic blood pressure, expert opinion for diastolic.
The guidelines recommend a blood pressure goal of less than 130/80 mm Hg for all patients, including the elderly and patients with chronic kidney disease or diabetes.
The SPRINT trial,2 which showed better cardiovascular outcomes in the intensive treatment group (aiming for systolic pressure < 120 mm Hg) compared with a standard treatment group (aiming for systolic pressure < 140 mm Hg), excluded participants with diabetes and severe chronic kidney disease (estimated glomerular filtration rate < 20 mL/min/m2 and proteinuria > 1 g/day), and those who were in nursing homes or had dementia.
The Action to Control Cardiovascular Risk in Diabetes (ACCORD) blood pressure trial showed that intensive blood pressure control did not have cardiovascular benefits compared with standard therapy.17 However, many now believe that the study may have been underpowered due to its design, and a meta-analysis of the results from SPRINT and ACCORD suggested that findings from both trials were consistent, favoring intensive blood pressure control in a high-risk population.18
While the totality of evidence favors a lower achieved blood pressure for many patients, this lower goal may be difficult to achieve in many, particularly those with vascular stiffness, which is common in the elderly. These patients also tend to have low diastolic pressure, and lowering diastolic pressure below 60 mm Hg in those with documented coronary artery disease could increase the risk of adverse cardiovascular outcomes.19,20 The guidelines do not address the potential issues with lowering diastolic blood pressure.
Our opinion. While a “universal” blood pressure goal may simplify decision-making, we believe it is important to individualize goals, taking into account patient characteristics, lifestyle factors, medication side effects, patient preferences, cost issues, and adherence to therapy.
The goal blood pressure should also consider the method of measurement. Systolic blood pressure readings have been reported to be 5 to 10 mm Hg lower with automated office measurement than with routine office measurement.21
It is also not clear that the magnitude of absolute benefit from pursuing more intensive blood pressure control with antihypertensive therapy in patients with high cardiovascular risk (as in SPRINT) would translate to similar benefits in a lower-risk population. Thus, we believe that in patients with lower cardiovascular risk, a goal blood pressure of less than 140/90 mm Hg (if routine office measurement is done) and less than 135/85 mm Hg (if automated office measurement is done) would be reasonable.
We also believe that it is reasonable to relax these goals in the very elderly (age ≥ 80), especially those who are frail and at risk of falls, with low diastolic pressures. In these patients, we recommend individualizing blood pressure goals that can be achieved without significant side effects from antihypertensive therapy.
Nonpharmacologic therapy
Strong recommendation, based on high-quality evidence from randomized controlled trials
Nonpharmacologic therapy and lifestyle modification are appropriately emphasized in the new guidelines. Most of the lifestyle changes that are recommended are in concordance with prior JNC 7 recommendations.3
Recognizing the roles of sodium and potassium in the pathogenesis of hypertension, the guidelines emphasize a diet that is higher in potassium, the DASH (Dietary Approaches to Stop Hypertension) diet, and a low-sodium diet. The recommended optimal goal of sodium intake of less than 1,500 mg/day may be difficult to achieve with a Western diet, and there is debate about the potential adverse effects of a very-low sodium diet.22 The general recommendation for sodium intake of less than 2,300 mg/day is supported in the literature, and it is unclear if further reduction has additional beneficial effects on blood pressure.23
The guidelines recommend a 3- to 6-month reassessment of patients who are prescribed risk-factor modification, but are unclear about initiation of pharmacologic therapy or other steps if these low-risk patients have not responded to lifestyle modifications alone at the time of reassessment.
Pharmacologic therapy
Strong recommendation, based on high-quality evidence from randomized controlled trials for systolic blood pressure, expert opinion for diastolic blood pressure for those with atherosclerotic cardiovascular disease risk 10% or greater, and limited data for those with risk less than 10%.
Pharmacologic therapy is recommended in patients with stage 1 hypertension and pre-existing cardiovascular disease or 10-year risk of atherosclerotic cardiovascular disease of 10% or more, and in those with stage 2 hypertension even if their 10-year risk is less than 10%.
In the absence of compelling indications, the primary drugs recommended for initial therapy are:
- Thiazide or thiazide-type diuretics (preferably chlorthalidone)
- Angiotensin-converting enzyme (ACE) inhibitors
- Angiotensin II receptor blockers (ARBs)
- Calcium channel blockers (CCBs).
In black adults, thiazide diuretics or CCBs are recommended for initial therapy. Beta-blockers are not recommended as first-line agents in the absence of a compelling indication, although meta-analyses that suggested beta-blockers are less effective than other classes of agents included trials that used beta-blockers in doses now considered suboptimal. ACE inhibitors or ARBs are recommended as initial therapy in proteinuric patients with chronic kidney disease or diabetes. Combining an ACE inhibitor and an ARB or renin inhibitor is potentially harmful and is not recommended. The guidelines provide a helpful table describing important characteristics and available dosage forms of the commonly used antihypertensive agents.
These recommendations are concordant with the JNC 8 panel recommendations,5 and differ from JNC 7, which recommended thiazide-type diuretics as first-line therapy.3 The European guidelines recommend that all major classes of antihypertensive agents, including beta-blockers, are suitable for initiation of therapy.24 The UK National Institute for Clinical Excellence guidelines adopt an age-based approach to deciding initial therapy—with ACE inhibitors or ARBs favored in those below the age of 55 and CCBs in those who are 55 and older.25
Starting with a single antihypertensive agent is recommended for stage 1 hypertension with increased cardiovascular risk, and starting with 2 agents (either separately or in fixed-dose combination) is recommended for stage 2 hypertension. The guidelines emphasize a team-based approach to improve hypertension care, using adjunctive interventions such as telehealth strategies and leveraging electronic medical records to guide quality improvement initiatives.
Our opinion. We agree with Bakris and Sorrentino26 that general patient profiles should be considered to decide on efficient pharmacologic management in clinical practice—thiazide diuretics would be best in those who are volume-expanded; ACE inhibitors, ARBs, or CCBs in those who are obese or have metabolic syndrome; and beta-blockers or nondihydropyridine CCBs in those who are hyperadrenergic. More patients will likely be classified as having resistant hypertension based on the blood pressure goal of less than 130/80 mm Hg, which may require greater use of mineralocorticoid receptor antagonists such as spironolactone.
