title: Nocturnal home hemodialysis improves baroreflex effectiveness index of end-stage renal disease patients.
abstract: BACKGROUND
  In patients with end-stage renal disease receiving conventional hemodialysis, both the frequency with which brief rises or falls in systolic blood pressure initiate concordant changes in pulse interval (arterial baroreflex effectiveness index), and the gain of reflex heart rate responses to these stimuli (arterial baroreflex sensitivity) are diminished. In chronic renal failure, low baroreflex effectiveness index and baroreflex sensitivity are associated with increased rates of all-cause mortality and sudden death, respectively. Conversion to home nocturnal hemodialysis augments baroreflex sensitivity but its effects on baroreflex effectiveness index have not been reported.
  
  
  METHODS
  In 20 consecutive hypertensive conventional hemodialysis patients training to transition to nocturnal hemodialysis (age 41 +/- 2 years; mean +/- standard error), baroreflex effectiveness index, baroreflex sensitivity (sequence method) and total arterial compliance (stroke volume/pulse pressure) were determined during quiet rest before and 2 months after conversion.
  
  
  RESULTS
  With nocturnal hemodialysis, dialysis frequency doubled, the dose per session increased by 70% and antihypertensive medications were withdrawn (from 2.5 +/- 0.3 to 0.2 +/- 0.1 drugs/patient, P < 0.01) because systolic blood pressure fell (from 139 +/- 5 to 119 +/- 4 mmHg, P < 0.05). Baroreflex effectiveness index increased from (0.33 +/- 0.03 to 0.42 +/- 0.03, P = 0.01). Baroreflex sensitivity increased from 5.60 +/- 0.88 to 8.48 +/- 1.60 ms/mmHg (P < 0.05). Changes in total arterial compliance correlated with changes in baroreflex sensitivity (r = 0.63, P = 0.004) but not baroreflex effectiveness index (r = 0.05, P = 0.95), suggesting independent mechanisms for their attenuation and recovery in end-stage renal disease.
  
  
  CONCLUSIONS
  Nocturnal hemodialysis increases baroreflex effectiveness index in addition to baroreflex sensitivity. The hypothesis that such changes might reduce cardiovascular event rates in this high-risk population merits prospective evaluation. More frequent engagement of the arterial baroreflex after conversion to nocturnal hemodialysis may improve short-term cardiovascular regulation.
authors.affiliation: University Health Network and Mount Sinai Hospital Department of Medicine, University of Toronto, 200 Elizabeth Street, Ontario, Canada. christopher.chan@uhn.on.ca
authors.forename: Christopher T
authors.initials: CT
authors.lastname: Chan
authors.forename: Xiou Seeger
authors.initials: XS
authors.lastname: Shen
authors.forename: Peter
authors.initials: P
authors.lastname: Picton
authors.forename: John
authors.initials: J
authors.lastname: Floras
mesh_terms: D000328:Adult; D017704:Baroreflex / Q000502:physiology*; D001794:Blood Pressure / Q000502:physiology; D002940:Circadian Rhythm / Q000502:physiology; D005260:Female; D006437:Hemodialysis, Home / Q000379:methods*; D006801:Humans; D006977:Hypertension, Renal / Q000453:epidemiology / Q000503:physiopathology / Q000517:prevention & control*; D007676:Kidney Failure, Chronic / Q000453:epidemiology / Q000503:physiopathology* / Q000628:therapy*; D008297:Male; D012307:Risk Factors; D013318:Stroke Volume / Q000502:physiology; D016896:Treatment Outcome