Do NOT Abandon Diastole

Systolic and diastolic blood pressure elevations (<130/80 mm Hg) independently predict myocardial infarction, ischemic stroke, and hemorrhagic stroke, even though increased systolic pressure has a greater effect.

These findings, published July 18 in the New England Journal of Medicine, may put to rest the historical call to “abandon diastole” as a therapeutic target.

Goals for blood pressure management have changed over time with early thought being that isolated diastolic hypertension conferred the greater risk for cardiovascular (CV) events such as myocardial infarction and stroke.

Results from the pivotal Framingham Heart Study, however, shifted focus to elevations in systolic blood pressure as more important in predicting negative CV outcomes and clinical practice to a “near-exclusive focus” on managing systolic hypertension.

Results from the landmark Framingham Heart Study, however, shifted clinical practice to a
"near-exclusive focus" on managing systolic hypertension.

Writing in the new study’s discussion, Alexander C. Flint, MD, PhD, Department of Neuroscience, Kaiser Permanente in Redwood City, CA, and colleagues, state that attention solely on reducing systolic blood pressure “would be in appropriate.” Their results bear out this comment.

In 2017 the guidelines for blood pressure management were revised to accommodate high-risk patients by lowering the threshold for a diagnosis of hypertension from 140/90 mm Hg to 130/80 mm Hg. The previous threshold was retained for patients with fewer comorbidities and lower risk for cardiovascular events.

Why not simply treat all patients to the lower blood pressure threshold? The authors point out that more aggressive treatment for all may lead to patients being treated to the point of hypotension or dangerously low diastolic blood pressure.

The authors’ investigation was twofold:

• Determine the relative risk conferred by systolic and diastolic hypertension independently on cardiovascular outcomes.

• Explore the impact of the 2 different thresholds for systolic and diastolic blood pressure on outcomes.

The retrospective cohort study included 1.3 million adult outpatients being treated for hypertension at Kaiser Permanente Northern California.

Primary outcome: a composite of first episode of myocardial infraction, ischemic stroke, or hemorrhagic stroke during the 8-year observation period.

Next: Study results and implications

Results support dual targets

As both diastolic and systolicblood pressure increased over the established thresholds so did the risk for adverse cardiovascular outcomes. This relationship becomes most prominent at measurements >140 mm Hg systolic and >88 mm Hg diastolic which is in keeping with traditional thresholds.

Greater risk for cardiovascular events was seen with systolic pressure elevation than diastolic pressure elevation however both were independently associated with adverse outcomes.

Patients with isolated systolic hypertension (>140 mm Hg) and lower diastolic pressures were at the highest risk for cardiovascular events.

Take Home Points

Dr. Flint and colleagues point out that, “it has been argued, on the basis of data from the Framingham Heart Study, that treatment for hypertension could improve with measurement of only systolic blood pressure.”

They go on to explain, “Our results show that this would be inappropriate: although systolic blood pressure indeed had a greater effect, systolic and diastolic blood pressures each independently influenced cardiovascular outcomes, and therefore diastolic blood pressure ought not to be ignored.”

This study solidifies that physicians in clinical practice should be monitoring and treating both systolic and diastolic hypertension. Targeting a lower threshold (ie, >130/80 mm Hg) may be appropriate for patients at higher risk for cardiovascular events and should be a decision made in discussion with an individual patient that weighs all relevant factors.

Source:

Flint AC, Conell C, Ren X, et al. Effect of systolic and diastolic blood pressure on cardiovascular outcomes. N Engl J Med 2019;381:243-51.
DOI: 10.1056/NEJMoa1803180