title: Different associations between beta-blockers and other antihypertensive medication combinations with brachial blood pressure and aortic waveform parameters.
abstract: BACKGROUND
  Comparing the relationships of antihypertensive medications with brachial blood pressure (BP) and aortic waveform parameters may help clinicians to predict the effect on the latter in brachial BP-based antihypertensive therapy. We aimed to make such comparisons with new waveform measures and a wider range of antihypertensive regimens than examined previously.
  
  
  METHODS
  Cross-sectional analysis of 2933 adults (61% male; aged 50-84years): 1637 on antihypertensive treatment and 1296 untreated hypertensives. Sixteen medicine regimens of up to 4 combinations of drugs from 6 antihypertensive classes were analysed. Aortic systolic BP, augmentation index (AIx), excess pressure integral (EPI), backward pressure amplitude (Pb), reflection index (RI) and pulse wave velocity (PWV) were calculated from aortic pressure waveforms derived from suprasystolic brachial measurement.
  
  
  RESULTS
  Forest plots of single-drug class comparisons across regimens with the same number of drugs (for between 1- and 3-drug regimens) revealed that AIx, Pb, RI and/or loge(EPI) were higher (maximum difference=5.6%, 2.2mmHg, 0.0192 and 0.13 loge(mmHg⋅s), respectively) with the use of a beta-blocker compared with vasodilators and diuretics, despite no brachial systolic and diastolic BP differences. These differences were reduced (by 34-57%) or eliminated after adjustment for heart rate, and similar effects occurred when controlling for systolic ejection period or diastolic duration.
  
  
  CONCLUSIONS
  Beta-blocker effects on brachial BP may overestimate effects on aortic waveform parameters. Compared to other antihypertensives, beta-blockers have weaker associations with wave reflection measures and EPI; this is predominantly due to influences on heart rate.
authors.affiliation: School of Population Health, University of Auckland, Auckland, New Zealand. Electronic address: j.sluyter@auckland.ac.nz.
authors.forename: John D
authors.initials: JD
authors.lastname: Sluyter
authors.affiliation: Institute of Cardiovascular Sciences, University College London, London, UK.
authors.forename: Alun D
authors.initials: AD
authors.lastname: Hughes
authors.affiliation: Institute for Biomedical Technologies, Auckland University of Technology, Auckland, New Zealand.
authors.forename: Andrew
authors.initials: A
authors.lastname: Lowe
authors.affiliation: Department of Bioengineering, Imperial College London, London, UK.
authors.forename: Kim H
authors.initials: KH
authors.lastname: Parker
authors.affiliation: Department of Emergency Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, USA.
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Camargo
authors.affiliation: Health & Environment Department, AIT Austrian Institute of Technology, Vienna, Austria.
authors.forename: Bernhard
authors.initials: B
authors.lastname: Hametner
authors.affiliation: Health & Environment Department, AIT Austrian Institute of Technology, Vienna, Austria.
authors.forename: Siegfried
authors.initials: S
authors.lastname: Wassertheurer
authors.affiliation: School of Population Health, University of Auckland, Auckland, New Zealand.
authors.forename: Robert K R
authors.initials: RK
authors.lastname: Scragg
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D000319:Adrenergic beta-Antagonists / Q000008:administration & dosage; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000008:administration & dosage; D055109:Ankle Brachial Index / Q000379:methods; D000959:Antihypertensive Agents / Q000008:administration & dosage; D001011:Aorta / Q000187:drug effects / Q000502:physiology; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology; D001795:Blood Pressure Determination / Q000379:methods; D002121:Calcium Channel Blockers / Q000008:administration & dosage; D003430:Cross-Sectional Studies; D004232:Diuretics / Q000008:administration & dosage; D004359:Drug Therapy, Combination; D005500:Follow-Up Studies; D063177:Pulse Wave Analysis / Q000379:methods
chemical_list: D000319:Adrenergic beta-Antagonists; D000806:Angiotensin-Converting Enzyme Inhibitors; D000959:Antihypertensive Agents; D002121:Calcium Channel Blockers; D004232:Diuretics
keywords: Arterial stiffness; Beta-blocker; Central blood pressure; Pulse waveform; Vasodilating antihypertensive agents; Wave reflection