Low dialysate potassium and central arterial pressure waveform

Figures & data

Table I. Characteristics of patients treated with hemodialysis, divided in two groups by concentration of dialysate potassium.

	Dialysate potassium
	1 mmol/L	2 or 3 mmol/L
Variable	(n = 9)	(n = 14)	P value
Age, years	65.4 ± 12.8	71.4 ± 9.3	NS
Male	6 (67%)	7 (50%)	NS
Height, cm	167.4 ± 8.0	171.7 ± 9.3	NS
Weight, kg	73 ± 11	74 ± 11	NS
Diabetes mellitus	1 (11%)	3 (21%)	NS
History of cardiovascular disease	4 (44%)	8 (57%)	NS
Current smoker	2 (22%)	2 (14%)	NS
Functioning arteriovenous fistula	6 (67%)	6 (43%)	NS
LDL, mmol/L	1.9 ± 0.7	2.2 ± 0.7	NS
HDL, mmol/L ^a	1.0 (0.9–1.4)	1.4 (0.9–2.6)	0.01
Triglycerides, mmol/L	2.3 ± 0.9	1.5 ± 0.6	0.02
Creatinine, µmol/L	787 ± 168	604 ± 172	0.03
Albumin, g/L	37.6 ± 2.1	34.5 ± 3.9	0.05
CRP, mg/L ^a	8.6 (3.4–75)	6.5 (0.2–89)	NS
Parathyroid hormone, pmol/L ^a	19 (13–68)	22 (7–62)	NS
Dialysis vintage, months ^a	18 (5–104)	7.5 (2–47)	0.02
Ultrafiltration per dialysis session, L	2.46 ± 1.5	1.86 ± 1.0	NS
HDF	2 (22%)	1 (7%)	NS

Mean ± SD or n (%).

^a Median (range).

HDF = hemodiafiltration.

Table II. Hemodynamic parameters in patients treated with hemodialysis, divided in two groups by concentration of dialysate potassium.

		Dialysate potassium
		1 mmol/L	2 or 3 mmol/L
Variable		(n = 9)	(n = 14)	P value
AIx	Before dialysis, %	31 ± 9.5	24 ± 8.0	0.089
	After dialysis, %	17 ± 6.1	23 ± 8.1	0.064
Peripheral SBP	Before dialysis, mmHg	162 ± 26	151 ± 24	NS
	After dialysis, mmHg	141 ± 24	148 ± 28	NS
Peripheral DBP	Before dialysis, mmHg	81 ± 15	78 ± 10	NS
	After dialysis, mmHg	77 ± 19	81 ± 10	NS
MAP	Before dialysis, mmHg	110 ± 20	101 ± 11	NS
	After dialysis, mmHg	96 ± 19	102 ± 15	NS
Heart rate	Before dialysis, bpm	70 ± 12	71 ± 11	NS
	After dialysis, bpm	75 ± 11	71 ± 10	NS
Central SBP	Before dialysis, mmHg	151 ± 29	136 ± 22	NS
	After dialysis, mmHg	123 ± 23	134 ± 26	NS
Central DBP	Before dialysis, mmHg	83 ± 16	78 ± 10	NS
	After dialysis, mmHg	78 ± 19	82 ± 11	NS

Mean ± SD.

AIx = augmentation index at heart rate 75 bpm; DBP = diastolic blood pressure; MAP = mean arterial pressure; SBP = systolic blood pressure.

Figure 1. Relative change of augmentation index in the two study groups (Group 1 = dialysate potassium 1 mmol/L; Group 2 = dialysate potassium 2 or 3 mmol/L) is presented using a boxplot with the square representing the 25th–75th percentile, the T-lines the 10th–90th percentile, and the circles representing observations <10th and >90th percentile.

Figure 2. Boxplots of relative change of central systolic pressure and mean arterial pressure in the two study groups. A: Relative change of central systolic pressure. B: Relative change of mean arterial pressure. (Group 1 = dialysate potassium 1 mmol/L; Group 2 = dialysate potassium 2 or 3 mmol/L). The square represents the 25th–75th percentile, the T-lines the 10th–90th percentile, and the circles representing observations <10th and >90th percentile.