title: Do higher dialysate calcium concentrations increase vascular stiffness in haemodialysis patients as measured by aortic pulse wave velocity?
abstract: BACKGROUND
  Haemodialysis patients have an increased prevalence of hypertension and risk of cardiovascular mortality and stroke. Higher dialysate calcium concentrations have been reported to cause both an acute and chronic increase in arterial stiffness. We therefore looked at changes in arterial stiffness in established haemodialysis patients to determine whether there was a threshold effect of dialysate calcium concentration linked to change in arterial stiffness.
  
  
  METHODS
  We performed pulse wave velocity measurements six months apart in patients dialysing with calcium concentrations of 1.0, 1.25, 1.35 and ≥1.5 mmol/l.
  
  
  RESULTS
  289 patients, 62.2% male, mean age 65.5 ± 15.7 years, weight body mass index 25.8 ± 5.4 kg/m2 ,47.9% diabetic were studied. Systolic blood pressure (SBP) was 148.4 ± 28.6 mmHg and diastolic blood pressure (DBP) 80.2 ± 15.5 mmHg. Mean pulse wave velocity increased over time (9.66 ± 2.0 vs 10.13 ± 2.16 m/s; p < 0.001), but there was no change in aortic augmentation index (38.7 ± 16.3 vs 39.8 ± 15.6%) or central aortic pressure (149.6 ± 33.3 vs 150.4 ± 31.9 mmHg).Pulse wave velocity did not differ between the four groups either at start or end of the study, but increased both in the groups dialysing with a calcium concentration of 1.0 mmol/l (9.64 ± 1.94 vs 10.45 ± 1.98 m/s, p = 0.0028) and also with 1.35 mmol/l (9.75 ± 1.96 vs 10.21 ± 2.18 m/s, p = 0.02).
  
  
  CONCLUSIONS
  Pulse wave velocity increased over the six months study. As pulse wave velocity increased in the group dialysing using the lowest dialysate calcium, it is likely that factors, other than simple net calcium influx and efflux during dialysis according to dialysate calcium concentration are involved with vascular stiffening.
authors.affiliation: UCL Centre for Nephrology, Royal Free hospital, University College London Medical School, Rowland Hill Street, London NW3 2PF, UK. andrewdavenport@nhs.net.
authors.forename: Evangelia
authors.initials: E
authors.lastname: Charitaki
authors.forename: Andrew
authors.initials: A
authors.lastname: Davenport
mesh_terms: D000368:Aged; D001011:Aorta / Q000187:drug effects / Q000503:physiopathology; D062186:Arterial Pressure / Q000187:drug effects*; D002118:Calcium / Q000008:administration & dosage*; D015314:Dialysis Solutions / Q000008:administration & dosage*; D004305:Dose-Response Relationship, Drug; D055119:Elastic Modulus / Q000187:drug effects; D005260:Female; D006801:Humans; D008297:Male; D063177:Pulse Wave Analysis / Q000379:methods; D006435:Renal Dialysis / Q000379:methods*; D051436:Renal Insufficiency, Chronic / Q000503:physiopathology* / Q000534:rehabilitation*; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014655:Vascular Resistance / Q000187:drug effects*
chemical_list: D015314:Dialysis Solutions; D002118:Calcium