Could Lowering Diastolic BP Increase Risk of Myocardial Damage?

Lowering of diastolic blood pressure (DBP) that occurs with reductions in systolic blood pressure (SBP) in patients taking antihypertensive therapies is associated with subclinical myocardial damage and coronary heart disease (CHD) events, according to a recent study.

Optimal SBP levels are still in question, with previous studies suggesting benefits related to SBP levels of 120 mm Hg. However, achieving levels this low may also reduce DBP levels enough to affect myocardial perfusion.
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In order to examine the association between DBP and myocardial damage, CHD, stroke, and mortality, researchers conducted a study of 11,565 adults from the Atherosclerosis Risk In Communities cohort.

Compared with participants with DBP between 80 and 89 mm Hg at baseline, the adjusted odds ratio of having high-sensitivity cardiac troponin-T of 14 ng/L or more was 2.2 and 1.5 for those with DBP of less than 60 mm Hg and from 60 to 69 mm Hg, respectively. Low baseline DBP was also associated with progressive myocardial damage, and compared with a DBP between 80 and 80 mm Hg, a DBP of less than 60 mm Hg was associated with CHD and mortality, but not stroke.

“Particularly among adults with an SBP ≥120 mm Hg, and thus elevated pulse pressure, low DBP was associated with subclinical myocardial damage and CHD events. When titrating treatment to SBP <140 mm Hg, it may be prudent to ensure that DBP levels do not fall below 70 mm Hg, and particularly not below 60 mm Hg,” the researchers concluded.

—Michael Potts

Reference:
McEvoy JW, Chen Y, Rawlings A, et al. Diastolic blood pressure, subclinical myocardial damage, and cardiac events. J Am Coll Cardiol. 2016;68(16):1713-1722.