title: Diverse effects of interdialytic intervals on central wave augmentation in haemodialysis patients.
abstract: BACKGROUND
  Increased arterial stiffness is a common finding and independent predictor of mortality in end-stage renal disease (ESRD) patients. A long interdialytic interval was associated with increased risk of cardiovascular death in patients receiving conventional haemodialysis (HD). This is the first study to examine the effects of a long (3-day) versus short (2-day) interdialytic period on arterial elasticity in HD patients.
  
  
  METHODS
  Seventy ESRD patients receiving standard HD three times per week were studied at the start and end of a 3-day and a 2-day interdialytic interval. At each time point, applanation tonometry of peripheral arteries was performed to assess arterial stiffness and wave reflection parameters. Aortic and brachial pulse wave velocities (PWV) were recorded as measures of arterial stiffness and augmentation index (AIx) as a measure of wave reflections.
  
  
  RESULTS
  AIx, heart-rate-adjusted AIx and augmentation pressure were significantly increased during both interdialytic intervals, whereas aortic and brachial PWVs remained unchanged. The interdialytic increases in all the three AIx parameters were significantly higher during the 3-day interval in comparison to the 2-day interval (P < 0.001 for all comparisons). In contrast, no significant differences in interdialytic changes of aortic (P = 0.355) and brachial (P = 0.319) PWVs were noted between the two intervals. Mixed linear model analysis revealed that central aortic systolic blood pressure (SBP) and body weight, but not aortic or brachial PWV, were independent determinants of the change in heart-rate-adjusted AIx throughout the study.
  
  
  CONCLUSIONS
  AIx is increased between HD sessions, whereas arterial elasticity is not. This interdialytic increase in central wave augmentation is more pronounced during the 3-day interval, suggesting a mechanism possibly involved in the elevated cardiovascular risk of HD patients at this time point.
authors: Section of Nephrology and Hypertension, 1st Department of Medicine, AHEPA University Hospital, Thessaloniki, Greece.
authors: Panagiotis I
authors: PI
authors: Georgianos
authors: Pantelis A
authors: PA
authors: Sarafidis
authors: Anna-Bettina
authors: AB
authors: Haidich
authors: Antonios
authors: A
authors: Karpetas
authors: Dimitrios
authors: D
authors: Stamatiadis
authors: Pavlos
authors: P
authors: Nikolaidis
authors: Anastasios N
authors: AN
authors: Lasaridis
mesh_terms: D001783:Blood Flow Velocity; D002318:Cardiovascular Diseases / Q000209:etiology*; D004548:Elasticity; D005260:Female; D005500:Follow-Up Studies; D005919:Glomerular Filtration Rate; D006801:Humans; D007676:Kidney Failure, Chronic / Q000150:complications* / Q000628:therapy; D007677:Kidney Function Tests; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D006435:Renal Dialysis / Q000009:adverse effects*; D012307:Risk Factors; D013997:Time Factors; D014655:Vascular Resistance; D059289:Vascular Stiffness
keywords: arterial stiffness; augmentation index; haemodialysis; interdialytic interval; pulse wave velocity