Blood Pressure

Alexander Flint, MD, PhD, on Managing Systolic and Diastolic BP in Hypertension

The effects of systolic blood pressure (SBP) and diastolic blood pressure (DBP) on cardiovascular outcomes are unclear, especially in light of recent revisions to hypertension guidelines that cite 2 different thresholds. A new analysis determined the effect of the burden of systolic and diastolic hypertension on several cardiovascular (CV) outcomes over 8 years. Lead author Alexander Flint, MD, PhD, answered our questions about his study.

Dr Flint is a neurointensivist and stroke specialist at Kaiser Permanente in Redwood City, California.

CARDIOLOGY CONSULTANT: Can you tell us more about your study and its findings?

Alexander Flint: There has been a pendulum swing over the years toward the view that SBP is the only component of blood pressure that contributes to the risk of adverse outcomes like heart attack or stroke. Our study brought a “big data” approach to this issue and found:

  • Both SBP and DBP contribute strongly and independently to the risk of myocardial infarction or stroke.
  • The independent impact of systolic and diastolic hypertension is seen at either threshold used for defining hypertension in the latest AHA/ACC guidelines (>140/90 mm Hg and >130/80 mm Hg). This observation serves to support the more aggressive treatment goals put forward in the latest guideline revision.
  • After controlling for covariates like age and comorbidities, we do not see evidence for a direct diastolic J-curve relationship with adverse CV outcomes (age and comorbidities explain the appearance of a J-curve in unadjusted analysis). This observation should alleviate concerns held by some clinicians that more aggressive treatment targets could paradoxically increase risk by way of lower diastolic pressures.

CARDIO CON: How might these findings affect clinical practice or how systolic/diastolic blood pressure is managed in patients with hypertension?

AF: Doctors and patients should make sure that both SBP and DBP get attention when it comes to diagnosing and treating hypertension. By providing additional support to the two thresholds for hypertension defined in the latest AHA/ACC guidelines (>140/90 mm Hg and >130/80 mm Hg), we hope that our results will encourage broader adoption of the guideline recommendations.

CARDIO CON: What do your results mean in the context of recent hypertension guidelines? Are the guidelines accurate in preventing cardiovascular events?

AF: The introduction of two thresholds (>130/80 mm Hg and >140/90 mm Hg) in the most recent ACC/AHA guideline revision was made based on evidence from a single large randomized controlled trial, the SPRINT trial. Some physicians have been resistant to changing how they practice based on evidence from a single source, so we hope that our study will increase physicians’ comfort with the guidelines, as our data provide additional support for the guideline change. Not only do we find a strong association between SBPs and DBPs and outcomes at both thresholds (>130/80 mm Hg and >140/90 mm Hg), but we also do not see evidence for a J-curve between DBPs and outcomes after controlling for covariates in this general population.

 

Reference:

Flint AC, Conell C, Ren X, et al. Effect of systolic and diastolic blood pressure on cardiovascular outcomes. N Engl J Med. 2019;381(3):243-251. https://doi.org/10.1056/NEJMoa1803180.