Blood Pressure and Heart Rate Variability in Patients on Conventional or Sodium-Profiling Hemodialysis

Figures & data

Table 1 Patients' baseline characteristics

	High-Na (n = 9)	Control (n = 11)
Gender (M/F)	4/5	6/5
Age (y)	64.6 ± 12	56.3 ± 4.9
DM (no./%)	2 (22.2)	2 (18.2)
Duration of HD treatment (y)	4.33 ± 1.59	4.32 ± 1.50
History of hypertension (no. /%)	8 (88.9)	7 (63.6)
Ischemic heart disease (no. /%)	6 (66.7)	4 (36.4)
LV systolic dysfunction^† (no. /%)	4 (44.4)	2 (18.2)
Dry weight (kg)	74.6 ± 5.9	64.1 ± 5.1

*mean + SE

^†Left ventricular ejection fraction (LVEF) < 40%.

Table 2 Effect on increasing Na dialysate profiling on plasma biochemistry

	Baseline		End of study		p (baseline vs. end )
Dialysis modality	High-Na	Control	High-Na	Control	High-Na	Control
Na (mmol/L)-Pre-D	140.3 ± 0.8	139.9 ± 0.8	140.8 ± 0.9	140.6 ± 0.3	NS	NS
Na (mmol/L)- Post-D	140.6±0.5	140.5 ± 0.4	142.0 ± 0.5^†	140.1 ± 0.5	0.056	NS
Urea (mmol)-Pre-D	23.8 ± 2.2	21.4 ± 2.3	23.9 ± 1.5	25.3 ± 1.5	NS	NS
Urea (mmol/L)-Post-D	8.1 ± 1.1	8.0 ± 0.9	7.8 ± 0.9	6.7 ± 0.8	NS	NS
Creatinine (μmol/L),Pre-D	896 ± 78	840 ± 74	886 ± 70	882 ± 73	NS	NS
Creatinine (μmol/L),Post-D	444 ± 85	347 ± 37	372 ± 51	339 ± 25	NS	NS
Albumin (g/L)	38.8 ± 0.08	38.0 ± 0.07	37.4 ± 0.16	37.8 ± 0.09	NS	NS
Calcium (mmol/L)	2.30 ± 0.10	2.38 ± 0.03	2.30 ± 0.05	2.32 ± 0.04	NS	NS
Hemoglobin (g/dL)	11.6 ± 0.3	11.3 ± 0.2	11.7 ± 0.2	11.6 ± 0.2	NS	NS
Osmolality (mosm /kg H2O)-, pre-D	320.2 ± 2.6	320.0 ± 1.6	322.0 ± 2.6	323.0 ± 1.4	NS	NS
Osmolality (mosm /kg H2O)-, post-D	304.5 ± 2.3	302.5 ± 1.5	307.3 ± 2.3^‡	301.7 ± 1.4	NS	NS

*Pre-dialysis values.

^†p < 0.02; ^‡p < 0.05 vs. control.

Abbreviations: Pre-D = pre-dialysis, Post-D = post-dialysis.

Table 3 Baseline and end-of-study fluid balance and number of hypotensive episodes in High-Na and control patients

	Baseline		End of study		p (baseline vs. end)
Dialysis modality	High-Na	Control	High-Na	Control	High-Na	Control
Weight gain (kg)	2.06 ± 0.24	2.18 ± 0.212	2.37 ± 0.23	2.31 ± 0.21	0.009	NS
% Weight gain	2.76 ± 0.23	3.71 ± 0.31	3.25 ± 0.26	3.71 ± 0.31	0.018	NS
Diuresis (ml)	344 ± 146	186 ± 86	222 ± 106	27 ± 19	0.045	0.046
Fluid intake (mL/24h)	2400 ± 233	2386 ± 195	2600 ± 227	2281 ± 208	0.012	NS
Hypotensive episodes (no./week)	1.50 ± 0.14	0.41 ± 0.19	0.86 ± 0.17	0.52 ± 0.26	0.056	NS
Pre-dialysis SBP (mm Hg)	130 ± 7	137 ± 7	137 ± 1	137 ± 9	NS	NS
Pre-dialysis DBP (mm Hg)	74 ± 3	80 ± 5	74 ± 2	74 ± 4	NS	NS
Pre-dialysis pulse pressure (mm Hg)	56 ± 5	56 ± 6	63 ± 7	63 ± 8	NS	NS

Abbreviations: SBP = systolic blood pressure, DBP = diastolic blood pressure.

*p < 0.001 vs. control.

Table 4 Baseline and end of study predialysis systolic blood pressure (SBP, mm Hg) measurements in patients with increased or decreased SBP over the year of study

	Increased SBP			Decreased SBP
	High-Na (n = 7)	Control (n = 5)	All (n = 12)	High-Na (n = 2)	Control (n = 6)	All (n = 8)
Baseline	132 ± 8	139 ± 7	135 ± 6	125 ± 15	135 ± 12	132 ± 9
End of study	145 ± 8	155 ± 9	149 ± 6	111 ± 5^‡	122 ± 13	119 ± 9^†

*Two patients with unchanged SBP were also included in this subgroup.

^†p < 0.05, ^‡p = 0.068 (NS) vs. patients with increased SBP.

Figure 1. Changes (baseline and end-of-study) in intradialytic sodium elimination (ΔJ_Na, mmol) and in predialysis systolic blood pressure (ΔSBP, mmHg) after one year in control (triangles), and in High-Na (squares) patients.

Figure 2. Baseline and end-of- study time-domain HRV measurements (median and interquartile range) in patients with increased (n = 12) and decreased or unchanged (n = 8) SBP. Data are presented as box plots. The box stretches from the 25^th to the 75^th percentile. The median is shown with a small black square in the box. The range (the upper and the lower extreme values) is indicated by the whiskers. Time domain measurements: RR (msec) = mean of five-minute mean RR interval between normal beats, SD (msec) = mean of five-minute standard deviation of RRs; SDANN (msec) = standard deviation of five-minute mean normal RR intervals; RMSSD (msec) = mean of five-minute root-mean square of differences of successive RRs.

Figure 3. Baseline and end-of- study frequency-domain HRV measurements (median and interquartile range), in patients with increased (n = 12) and decreased or unchanged (n = 8) SBP. Data are presented as box plots. The box stretches from the 25^th to the 75^th percentile. The median is shown with a small black square in the box. The range (the upper and the lower extreme values) is indicated by the whiskers. Frequency domain measurements: VLF (0–0.050 Hz) = very low frequency power; LF (0.05–0.2 Hz) = low frequency power; HF (0.2–0.4 Hz) = high frequency power, LF/HF = LF/HF ratio × 100. VLF, LF, HF (msec²/Hz), and LF/HF values were evaluated from consecutive five-minute epochs.