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Very low diastolic BP may damage myocardial tissue, elevate risk for CHD
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Low diastolic BP was linked to subclinical myocardial damage and CHD events, particularly among adults with systolic BP of at least 120 mm Hg, according to a study published in the Journal of the American College of Cardiology.
John W. McEvoy, MB, BCh, MHS, of the Johns Hopkins Ciccarone Center for the Prevention of Heart Disease, and colleagues analyzed data from 11,565 adult participants (mean age, 57 years; 57% women; 25% black) from the ARIC study.
Using high-sensitivity cardiac troponin T (hs-cTnT), the researchers investigated the association of diastolic BP with myocardial damage and with CHD, stroke or death over 21 years.
Key findings
The researchers found that, compared with patients who had diastolic BP between 80 mm Hg and 89 mm Hg at baseline, the adjusted OR of having hs-cTnT of at least 14 ng/L at that visit was 2.2 in those with diastolic BP less than 60 mm Hg and 1.5 in those with diastolic BP 60 mm Hg to 69 mm Hg. The researchers also found that low diastolic BP at baseline was independently linked to progressive myocardial damage according to estimated annual change in hs-cTnT over 6 years.
Compared with a diastolic BP of 80 mm Hg to 89 mm Hg, diastolic BP of less than 60 mm Hg was associated with incident CHD (HR = 1.49; 95% CI, 1.2-1.85) and mortality (HR = 1.32; 95% CI, 1.13-1.55), but not with stroke (HR = 1.13; 95% CI, 0.79-1.61). The relationship between diastolic BP and incident CHD was strongest in individuals with baseline hs-cTnT of at least 14 ng/L (P for interaction < .001). The combination of low diastolic BP, high hs-cTnT and incident CHD was most often seen in those with baseline systolic BP of at least 120 mm Hg, according to the researchers.
Consider implications
“There is increased likelihood that if we use [BP] drugs to push patients’ systolic [BPs] down to 120 [mm Hg] — which is a strategy supported by recent clinical trials — the consequence in those starting out with low diastolic [BPs] ... may be that the diastolic number falls so low that we risk doing damage,” McEvoy said in a press release. “Our key finding suggests that for some patients, there should perhaps be modification of intensive, antihypertensive treatment recommendations issued last year as a result of the SPRINT trial, and that physicians shouldn’t look at driving down [systolic BP] in isolation without considering implications of lowering [diastolic BP].”
Deepak L. Bhatt, MD, MPH, from the Brigham and Women’s Hospital Heart & Vascular Center and Harvard Medical School, and chief medical editor of Cardiology Today’s Intervention, wrote in an accompanying editorial, “Beyond any potential increase in [CV] events, in clinical practice excessive BP lowering can surely produce side effects. ... A key cautionary note about appropriate BP targets is that the majority of patients with hypertension are not optimally treated, even using thresholds higher than those that are currently being debated.” – by James Clark
Disclosure: McEvoy reports no relevant financial disclosures. Please see the full study for a list of the other researchers’ relevant financial disclosures. Bhatt reports financial ties with Amerin, Amgen, AstraZeneca, Belvoir Publications, Biotronik, Boston Scientific, Bristol-Myers Squibb, Cardax, Eisai, Elsevier Practice Update Cardiology, Ethicon, FlowCo, Forest Laboratories, HMP Communications, Ischemix, Medscape Cardiology, Medtronic, Pfizer, PLx Pharma, Regado Biosciences, Roche, Sanofi, St. Jude Medical, Takeda and WebMD.
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