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Effect of beta blockers on central aortic pressure in African-Americans

Haroon Kamran1, Louis Salciccioli, Carl Bastien

  • 1Division of Cardiovascular Medicine, State University of New York Downstate Medical Center, Brooklyn, New York 11203, USA.

Journal of the American Society of Hypertension : JASH
|March 19, 2011
PubMed

Insights

Beta-blocker therapy in African Americans lowers heart rate, impacting central blood pressure control. This heart rate reduction may explain why beta-blockers are less effective in this population.

Area of Science:

  • Cardiovascular Medicine
  • Pharmacology
  • Hypertension Research

Background:

  • Beta-blockers (BB) show reduced cardiovascular protection in African Americans (AA) compared to other antihypertensives.
  • Studies in Caucasians suggest impaired arterial wave reflection due to heart rate (HR) lowering by BBs may explain this disparity.
  • Understanding vascular effects of BBs in AA is crucial for optimizing hypertension management.

Purpose of the Study:

  • To evaluate the vascular effects of heart rate (HR) reduction induced by beta-blocker (BB) therapy in hypertensive African Americans (AA).
  • To determine if HR lowering by BBs influences central hemodynamic parameters in AA.
  • To compare the efficacy of BBs in central versus peripheral blood pressure control in AA.

Main Methods:

  • Applanation tonometry (Sphygmocor) was used to measure central systolic blood pressure (C-SBP), central pulse pressure (C-PP), augmented pressure (AP), and augmentation index (AI) in 506 subjects.
  • Subjects included 52% treated with BBs; data were analyzed using univariate, multivariate, and generalized linear model approaches.
  • Heart rate (HR) was assessed as a determinant of central hemodynamic parameters and its interaction with BB therapy was investigated.

Main Results:

  • Univariate analysis revealed inverse correlations between HR and BB use, C-SBP, AP, and AI (all P < .001).
  • Multivariate analysis identified peripheral systolic blood pressure (P-SBP) and HR as key determinants of C-SBP (R(2) = 0.95).
  • The BB group exhibited higher C-SBP (P < .05) and C-PP (P = .04) but similar P-SBP (P = .24) compared to the non-BB group. Adjusting for HR attenuated these differences, indicating HR's significant role.

Conclusions:

  • Beta-blocker use in hypertensive AA is associated with elevated central systolic blood pressure and lower pulse pressure, despite similar peripheral blood pressure.
  • Central systolic blood pressure is significantly influenced by heart rate, with HR reduction by BBs contributing to less effective central blood pressure control in AA.
  • The findings suggest that HR-dependent vascular effects of BBs contribute to their diminished efficacy in African Americans, mirroring observations in Caucasian populations.

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