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Background and Aims Hypertension is highly prevalent in dialysis patients and is often poorly controlled. Data on the ambulatory blood pressure (BP) profile of patients undergoing peritoneal dialysis (PD) are scarce. The aim of this study is to compare the ambulatory BP profile of PD patients with that of hemodialysis (HD) and to pre-dialysis CKD patients. Method 38 patients undergoing PD were matched in a 1:2 ratio for age, gender and dialysis vintage with 76 HD patients and in a 1:1 ratio for age and gender with 38 CKD stages 2-4 patients. Patients under PD and HD underwent 48-hour and CKD patients 24-hour ambulatory BP monitoring. BP levels were compared for the 48hour, 1st and 2nd 24hour, daytime and nighttime periods. Two-way mixed ANOVA analysis for repeated measurements was used to evaluate the effect of dialysis modality and time on ambulatory BP in PD and HD. Results During all periods studied, SBP and DBP were numerically higher but not statistically different in PD than in HD patients. SBP was significantly higher in PD or HD compared with predialysis CKD (PD:138.38±20.97; HD:133.75±15.5; CKD:125.52±13.4 mmHg, p=0.003; PD vs CKD: p=0.003; HD vs CKD: p=0.041 accordingly); significant differences were also evident during the daytime and nighttime periods. DBP displayed a similar trend in the total period studied (PD:82.34±15.22; HD:80.47±11.13; CKD:76.81±7.82 mmHg, p=0.108), but the difference significant only during the second nighttime period. Repeated-measurements analysis showed no effect of dialysis modality and no interaction between modality and time on ambulatory BP during all periods studied. Conclusion Average BP levels are similar between PD and HD patients, but higher for both groups compared to CKD counterparts. The dialysis modality had no significant effect on ambulatory BP profile.

Background and Aims Blood pressure variability (BPV) indices have been independently associated with cardiovascular events and mortality in hemodialysis (HD) patients. Data on short-term BPV in patients on peritoneal dialysis (PD) are totally absent. This study examined short-term BPV parameters of patients undergoing PD in comparison to HD and pre-dialysis chronic kidney disease (CKD) patients. Method 38 PD patients were matched for age, gender and dialysis vintage with 76 HD in 1:2 ratio patients and for age and gender with 38 patients with CKD stage 2-4 in 1:1 ration. BPV parameters [standard deviation (SD), weighted SD (wSD), coefficient-of-variation (CV) and average-real-variability (ARV)] were calculated from data from 48hour (PD, HD) and 24hour (CKD) ambulatory BP monitoring according to validated formulas. Results There were no significant differences in BPV indexes studied between PD and HD patients but all BPV indexes in these patients were numerically higher than those in CKD patients. Systolic ARV was significantly higher in PD or HD compared with predialysis CKD during the first and the second interdialytic 24hour periods, both daytime period and nighttime 2 (1st 24hour period: PD:11.86±3.19; HD:11.23±3.45; CKD:9.81±2.49, p=0.016, 2nd 24hour period: PD: 12.18±4.11; HD: 12.96±4.57; CKD: 9.81±2.49, p Conclusion BPV indices are similar between PD and HD patients and higher compared to CKD counterparts. Despite what was theoretically expected, PD patients demonstrate high fluctuations in BP in the absence of abrupt shifts in volume.

Background and Aims Endothelial dysfunction is associated with cardiovascular events and mortality in various disease states, including end-stage-renal-disease (ESRD). Novel technological approaches have emerged for real-time assessment of endothelial reactivity. This study examined forearm skin microcirculation using Laser Speckle Contrast Imaging (LSCi) before and after arterial occlusion in ESRD patients undergoing hemodialysis (HD) or peritoneal dialysis (PD) Method 38 patients undergoing HD were matched in a 1:1 ratio with 38 PD patients (for age, sex and dialysis vintage) and 38 controls (for age and sex). Skin microvascular reactivity parameters assessed with LSCI included baseline perfusion, occlusion perfusion, and peak perfusion during post-occlusive reactive hyperemia (PORH); time to peak perfusion; proportional change from baseline to peak perfusion; baseline and peak cutaneous vascular conductance (CVC); proportional change from baseline to peak CVC; and the amplitude of the PORH response (calculated as the difference between peak and baseline CVC). Results Baseline perfusion [HD: 46.97±14.6; PD: 49.32±18.07; controls: 42.02±11.94 Laser-Specle-Perfusion-Units (LSPU), p=0.097] and peak post-occlusion perfusion (104.77±28.68 vs 109.04±40.77 vs 116.96±30.96 LSPU, p=0.238) did not differ between groups. However, the post-occlusive vascular response was completely different, since time to peak response (HD: 7.24±6.99; PD: 10.68±9.45; controls: 11.11±5.1 sec, p=0.003) and the (%) increase from baseline to peak perfusion (HD: 133%±66; PD: 149%±125; controls: 187%±61, p=0.001) was significantly lower in ESRD patients. ESRD patients had also lower levels of peak CVC, indicating the maximum capillary recruitment (HD: 1.05±0.3; PD: 1.07±0.44; controls: 1.57±0.52 LSPU/mmHg, p Conclusion Using this novel non-invasive technology endothelial post-occlusive skin vasodilatory response was found to be similar between HD and PD patients and significantly impaired compared to controls. Future studies are needed to assess the prognostic implications of this microcirculatory functional defect.