title: Impact of heart rate on central hemodynamics and stroke: a meta-analysis of β-blocker trials.
abstract: BACKGROUND
  In a meta-analysis, we investigated effects of β-blockers on central hemodynamic measurements and explored the impact of heart rate (HR) on central hemodynamics and the risk of stroke.
  
  
  METHODS
  We searched randomized controlled trials that compared β-blockers with other classes of antihypertensive drugs in reducing central systolic blood pressure (cSBP) and augmentation index (cAI) and in preventing stroke. A random-effects model was used to compute pooled estimates.
  
  
  RESULTS
  In 9 trials (n = 754), β-blockers were less efficacious in reducing cAI than all the other classes of drugs (8.6%, P < 0.001). β-blockers were also less efficacious in reducing cSBP than angiotensin converting enzyme inhibitors (7.7 mm Hg, P = 0.02) and angiotensin receptor blockers (3.6 mm Hg, P = 0.005) but not the other classes of drugs (P ≥ 0.50). In a meta-regression analysis of these 9 trials, the baseline-adjusted difference in HR between randomized groups was associated with cAI (7.0% increase for each 10 bpm decrease in HR, P = 0.02), which was associated with cSBP (1.2 mm Hg increase for each 1% increase in cAI, P = 0.009). In 5 outcome trials, the pooled OR of stroke was 1.23 (P < 0.001), which would be accounted for by the difference in cSBP derived from the above meta-regression analysis.
  
  
  CONCLUSIONS
  Slowing HR with β-blockers may increase cAI and in turn may decrease cSBP less than with other classes of drugs. This mechanism might account for a smaller reduction in the risk of stroke when using β-blockers to treat hypertension.
authors: Centre for Epidemiological Studies and Clinical Trials, The Shanghai Institute of Hypertension, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, China.
authors: Feng-Hua
authors: FH
authors: Ding
authors: Yan
authors: Y
authors: Li
authors: Li-Hua
authors: LH
authors: Li
authors: Ji-Guang
authors: JG
authors: Wang
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use*; D000328:Adult; D000368:Aged; D057911:Angiotensin Receptor Antagonists / Q000627:therapeutic use; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000627:therapeutic use; D000959:Antihypertensive Agents / Q000627:therapeutic use*; D001794:Blood Pressure / Q000187:drug effects; D006339:Heart Rate / Q000187:drug effects*; D006439:Hemodynamics / Q000187:drug effects*; D006801:Humans; D006973:Hypertension / Q000188:drug therapy; D008875:Middle Aged; D016032:Randomized Controlled Trials as Topic; D012044:Regression Analysis; D020521:Stroke / Q000517:prevention & control*; D059289:Vascular Stiffness / Q000187:drug effects
chemical_list: D000319:Adrenergic beta-Antagonists; D057911:Angiotensin Receptor Antagonists; D000806:Angiotensin-Converting Enzyme Inhibitors; D000959:Antihypertensive Agents