Impact of Dialysate Sodium Concentration Lowering on Home Blood Pressure Variability in Hemodialysis Patients

Dialysate sodium and short-term blood pressure variability in patients with intradialytic hypertension: a randomized crossover study

Increased blood pressure (BP) variability (BPV) is associated with high cardiovascular risk in hemodialysis. Patients with intradialytic hypertension (IDH) also exhibit an increased cardiovascular risk compared to hemodialysis patients without this condition. The impact of non-pharmacological BP-lowering interventions on BPV in this population remains unknown. This analysis evaluated the effect of low (137mEq/L) compared to standard (140mEq/L) dialysate sodium concentration on short-term BPV in patients with IDH. In a randomized cross-over manner, 29 IDH patients underwent 4 hemodialysis sessions with low (137mEq/L) followed by 4 sessions with standard (140mEq/L) dialysate sodium or vice versa. 48 h ambulatory BP measurement was performed from the start of the 4th session on each dialysate sodium. BPV indices during the 48 h, 24 h, day-time and night-time periods were calculated. Mean 48 h BP was 5.3/2.6 mmHg lower with low compared to standard dialysate sodium concentration, (p = 0.005/p = 0.007 respectively). All 48 h systolic BPV indices examined showed non-significant differences between low and standard dialysate sodium (SBP-SD: 16.99 ± 5.39 vs. 16.98 ± 4.33 mmHg, p = 0.982; SBP-wSD: 15.93 ± 5.02 vs. 16.12 ± 4.16 mmHg, p = 0.769; SBP-ARV: 11.99 ± 3.67 vs. 11.45 ± 3.35 mmHg, p = 0.392; SBP-CV: 12.36 ± 3.65 vs. 11.92 ± 3.18%, p = 0.302, with low vs. standard dialysate sodium, respectively). Diastolic BPV indices were numerically, but not statistically, lower with low dialysate sodium. Overall, significant differences were observed in some comparisons with a trend for lower BPV during day-time 2 and higher BVP during night-time 2 with low dialysate sodium. In conclusion, low dialysate sodium concentration does not affect BPV levels in patients with IDH. Future research should explore alternative interventions to reduce BP and BPV in this high-risk population.

Echocardiographic left ventricular hypertrophy and geometry in Chinese chronic hemodialysis patients: the prevalence and determinants

Background

To investigate the prevalence of left ventricular hypertrophy (LVH) and explore left ventricular geometry in maintenance hemodialysis (MHD) patients, and to explore the risk factors of LVH which is an important predictor of cardiovascular events.

Methods

The subjects were patients who are on MHD for more than 3 months in Peking University People's Hospital from March 2015 to February 2017. Demographic and clinical data were retrospectively collected. Left ventricular mass was measured by echocardiography. LVH is defined by Left ventricular mass index (LVMI) > 115 g/m² for men and > 95 g/m² in women. LVMI and relative wall thickness were used to determine left ventricular geometry. Logistic regression was used to analyze the risk factors of LVH.

Results

Altogether, 131 patients including 77 males were enrolled. The median age was 60 (47, 69) years, with a median dialysis vintage of 48 (18, 104) months. There were 80 patients with LVH, the prevalence rate was 61.1%, and 66.3% of them were moderate to severe LVH. We found that (1) most of the patients were concentric hypertrophy; (2) one-third of the patients were concentric remodeling; (3) only 4 cases with normal geometry. The pre-dialysis serum sodium level and time average pre-dialysis systolic blood pressure (SBP) were independent risk factors of LVH.

Conclusion

LVH is prevalent in MHD patients. Concentric hypertrophy and concentric remodeling are the most common geometric patterns. Attention should be paid to long-term pre-dialysis SBP management and pre-dialysis sodium control as they might be potentially modifiable risk factors for LVH.

Optimization of dialysate bicarbonate in patients treated with online haemodiafiltration

Background

Metabolic acidosis is a common problem in haemodialysis patients, but acidosis overcorrection has been associated with higher mortality. There is no clear definition of the optimal serum bicarbonate target or dialysate bicarbonate. This study analysed the impact of reducing dialysate bicarbonate from 35 to 32 mEq/L on plasma bicarbonate levels in a cohort of patients treated with online haemodiafiltration (OL-HDF).

Methods

We performed a prospective cohort study with patients in a stable chronic OL-HDF programme for at least 12 months in the Hospital Clinic of Barcelona. We analysed pre- and post-dialysis total carbon dioxide(TCO₂₎ before and after dialysate bicarbonate reduction from 35 to 32 mEq/L, as well as the number of patients with a pre- and post-dialysis TCO₂ within 19–25 and ≤29 mEq/L, respectively, after the bicarbonate modification. Changes in serum sodium, potassium, calcium, phosphorous and parathyroid hormone (PTH) were also assessed.

Results

We included 84 patients with a 6-month follow-up. At 6 months, pre- and post-dialysis TCO₂ significantly decreased (26.78 ± 1.26 at baseline to 23.69 ± 1.92 mEq/L and 31.91 ± 0.91 to 27.58 ± 1.36 mEq/L, respectively). The number of patients with a pre-dialysis TCO₂ >25 mEq/L was significantly reduced from 80 (90.5%) to 17 (20.2%) and for post-dialysis TCO₂  >29 mEq/L this number was reduced from 83 (98.8%) to 9 (10.7%). PTH significantly decreased from 226.09 (range 172–296) to 182.50 (125–239)  pg/mL at 6 months (P < 0.05) and post-dialysis potassium decreased from 3.16 ± 0.30 to 2.95 ± 0.48 mEq/L at 6 months (P < 0.05). Sodium, pre-dialysis potassium, calcium and phosphorous did not change significantly.

Conclusions

Reducing dialysate bicarbonate concentration by 3 mEq/L significantly and safely decreased pre- and post-dialysis TCO₂, avoiding acidosis overcorrection and improving secondary hyperparathyroidism control. An individualized bicarbonate prescription (a key factor in the adequate control of acidosis) according to pre-dialysis TCO₂ is suggested based on these results.