Abstract
BackgroundTreatment of end stage renal disease patients with short daily hemodialysis has been associated with an improvement in blood pressure. It is unclear from these studies if anti-hypertensive management had been optimized prior to starting short daily hemodialysis. Also, the potential mechanism(s) of blood pressure improvement remain to be fully elucidated.Study Design, Setting and ParticipantsWe undertook a randomized cross-over trial in adult hypertensive patients with ESRD treated with conventional hemodialysis to determine: 1) if short-daily hemodialysis is associated with a reduction in systolic blood pressure after a 3-month blood pressure optimization period and; 2) the potential mechanism(s) of blood pressure reduction. Blood pressure was measured using Canadian Hypertension Education Program guidelines. Extracellular fluid volume (ECFV) was assessed with bioimpedance. Serum catecholamines were used to assess the sympathetic nervous system. Interleukin-6 (IL-6) and thiobarbituric acid reactive substances (T-BARS) were used as markers of inflammation and oxidative stress respectively.ResultsAfter a 3-month run-in phase in which systolic blood pressure improved, there was no significant difference in pre-dialysis systolic pressure between short-daily and conventional hemodialysis (p = 0.39). However, similar blood pressures were achieved on fewer anti-hypertensive medications with short daily hemodialysis compared to conventional hemodialysis (p = 0.01). Short daily hemodialysis, compared to conventional hemodialysis, was not associated with a difference in dry weight or ECFV (p = 0.77). Sympathetic nervous system activity as assessed by plasma epinephrine (p = 1.0) and norepinephrine (p = 0.52) was also not different. Markers of inflammation (p = 0.42) and oxidative stress (p = 0.83) were also similar between the two treatment arms.ConclusionsPatients treated with short daily, compared to conventional hemodialysis, have similar blood pressure control on fewer anti-hypertensive medications. The mechanism(s) by which short daily hemodialysis allows for decreased anti-hypertensive medication use remains unclear but effects on sodium balance and changes in peripheral vascular resistance require further study.Trial RegistrationClinicalTrials.gov NCT00759967
Highlights
More than 50% of the patients with end stage renal disease (ESRD) die from cardiovascular disease, a risk 10–20 times greater than the general population [1,2]
After a 3-month run-in phase in which systolic blood pressure improved, there was no significant difference in predialysis systolic pressure between short-daily and conventional hemodialysis (p = 0.39)
Similar blood pressures were achieved on fewer anti-hypertensive medications with short daily hemodialysis compared to conventional hemodialysis (p = 0.01)
Summary
More than 50% of the patients with end stage renal disease (ESRD) die from cardiovascular disease, a risk 10–20 times greater than the general population [1,2]. An expanded extracellular fluid volume (ECFV) and an increase in peripheral vascular resistance (PVR) due to hemodynamic/trophic effects of increased sympathetic nerve activity and inflammation are frequently quoted mechanisms contributing to hypertension in ESRD [4]. 24% of the patients treated with long dialysis appeared to have an expanded ECFV such that the authors hypothesized that normotension in these patients might be explained by the removal of a vasoactive hormone Their results are supported by a small randomized controlled trial of blood pressure control in 21 ESRD patients in which 7 patients had their dialysis time increased by 2 hours, 6 patients had their dialysis time increased by 2 hours and dry weight reduced, and 8 patients only had their dry weight reduced [14]. The potential mechanism(s) of blood pressure improvement remain to be fully elucidated
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