Association between arterial stiffness and peritoneal small solute transport rate

Loss of the Normal Gradient in Arterial Compliance and Outcomes of Chronic Kidney Disease Patients

BACKGROUND

In dialysis patients, loss of the normal gradient in arterial compliance, assessed by the pulse wave velocity (PWV) ratio, predicts all-cause mortality better than does carotid-femoral PWV (CF-PWV) alone. However, the prognostic significance of the PWV ratio for outcome in chronic kidney disease (CKD) patients remains unclear.

METHODS

In this longitudinal cohort study, CKD patients who visited our CKD management clinic between April 27, 2006, and March 27, 2008, were included and followed up. To assess the gradient in arterial compliance, the PWV ratio was calculated using CF-PWV divided by carotid-radial PWV.

RESULTS

A total of 209 patients in CKD stages 1-4 with a median follow-up of 3.74 years were included. Patients with higher PWV ratio were relatively older (p < 0.001) and had worse renal function (p < 0.001), more hypertension (p < 0.001), diabetes mellitus (p < 0.001), and cardiovascular or cerebrovascular disease (p < 0.001). The median time to patient outcome (death, renal replacement therapy, or double increase in serum creatinine from baseline) in the group with a PWV ratio above the median (89.8 months, 95% CI 84.2-95.5) was shorter than that in the group with a PWV ratio below the median (105.3 months, 95% CI 101.3-109.3, p = 0.001). Univariate Cox regression analysis showed that both PWV ratio and CF-PWV were significantly associated with patient outcome. In multivariate Cox regression analysis, both PWV ratio and CF-PWV were associated with patient outcome. However, the HR for CF-PWV (2.177, 95% CI 1.064-4.453, p = 0.033) was slightly higher than that for PWV ratio (2.091, 95% CI 1.049-4.167, p = 0.036). There was a significant interaction effect between PWV ratio and CKD stage. It was shown that patients with advanced CKD stages and higher PWV ratios had a significantly higher risk of adverse CKD outcome (p = 0.006).

CONCLUSIONS

The PWV ratio, as a measure of loss of the normal gradient in arterial compliance, was associated with CKD patient outcome. Patients with advanced CKD and a higher PWV ratio had a significantly higher risk of adverse CKD outcome.

Aortic-Brachial Stiffness Mismatch and Mortality in Peritoneal Dialysis Patients

Background/Aims: Possible predictive value of aortic-brachial arterial stiffness mismatch assessed by pulse wave velocity PWV ratio in peritoneal dialysis patients’ outcomes need to be further elucidated. The aim of this study is to investigate the predictor value of PWV ratio on peritoneal dialysis (PD) patients’ outcomes in China. Methods: In this longitudinal cohort study, patients who started PD during September 20, 2005, to February 05, 2008, were included. All the patients were followed until January 31, 2018. Aortic-brachial arterial stiffness mismatch was assessed using carotid-femoral pulse wave velocity divided by carotid-radial pulse wave velocity (PWV ratio). Results: A total of 181 incident PD patients were included. The median survival of patients in PWV ratio above median group (4.03 years, 95% CI 4.64-7.99 years) was shorter than that of PWV ratio below median group (10.43 years, 95% CI 9.74-11.12 years, p< 0.001). The cardiovascular mortality rate in PWV ratio above median group were significantly higher than that of PWV below median group (log rank test, p< 0.001). Univariate Cox regression analysis showed that both PWV ratio (HR 2.42, 95% CI 1.80-3.25, p< 0.001) and CF-PWV (HR 1.27, 95% CI 1.16-1.38, p< 0.001) were associated with high patients’ all-cause mortality. Multivariable Cox regression analysis showed that the PWV ratio was a strong and significantly predictor of cardiovascular mortality (HR 2.08 95% CI 1.16-3.71, p=0.014) after adjusting for coronary heart disease history (HR 2.39, 95% CI 1.20-4.76, p=0.013), diabetes mellitus history (HR 2.84, 95% CI 1.51-5.33, p=0.001). However, the CF-PWV was failed to be included as a significant predictor for both all-cause and CVD mortality in the multivariable Cox regression model. Conclusion: Aortic-brachial arterial stiffness mismatch as assessed by PWV ratio, a new arteries stiffness risk parameter, is a significant prognostic indicator of CVD mortality in PD patients. We demonstrated that the discriminative power of the PWV ratio for both all-cause and CVD mortality was better than that CF-PWV.

The risks of high ultrafiltration rate in chronic hemodialysis: implications for patient care

As dialytic practice has evolved, hemodialysis (HD) adequacy has come to be defined in terms of small molecule clearance. A growing body of evidence suggests that fluid dynamics, specifically ultrafiltration rate (UFR), bear clinical and physiological significance and should perhaps play a more central role in titrating HD therapy. Three recent studies have shown an independent association between higher UFR and mortality. Further work is needed to determine whether this relationship represents a direct toxic effect of rapid fluid perturbations or whether this association is a consequence of confounding on the basis of large interdialytic weight gain, as each would prompt a different therapeutic response. This mounting evidence builds the case that fluid management should play a more central role in the dialytic prescription and that more individualized approaches to fluid management should be encouraged.

Arterial pulse wave velocity and peritoneal transport characteristics independently predict hospitalization in Chinese peritoneal dialysis patients

OBJECTIVE

Cardiovascular disease (CVD) is the most common cause of mortality in chronic peritoneal dialysis (PD) patients. Increased arterial stiffness may be related to a high peritoneal permeability resulting in fluid overload in PD patients. We studied the relations between arterial stiffness, peritoneal transport, and radiographic parameters of systemic fluid overload in a cohort of Chinese PD patients.

DESIGN

Prospective cohort study.

SETTING

University referral center.

PATIENTS

We studied 107 PD patients. Vascular pedicle width and cardiothoracic ratio were measured from a plain postero-anterior chest radiograph. Pulse wave velocity (PWV) was determined at carotid-femoral (C-F) and carotid-radial sites. Peritoneal transport was determined by the dialysate-to-plasma ratio (D/P) of creatinine at 4 hours of dwell. Patients were followed for 9.4 +/- 4.6 months.

OUTCOME MEASURES

Duration of hospitalization; actuarial and technique survival.

RESULTS

There were no relationships between radiographic measures, arterial PWV, and D/P creatinine. However, both C-F PWV and D/P creatinine were independent predictors of the number of hospitalizations for CVD. None of the parameters correlated with mortality in this study.

CONCLUSIONS

There were no relationships between radiological parameters of fluid overload, peritoneal transport characteristics, and arterial PWV. Both C-F PWV and D/P creatinine were independent predictors of the number of hospitalizations for CVD. Our result suggests that arterial stiffness and high peritoneal transport each contribute to the development of CVD in this group of patients.

Reduced residual renal function is associated with endothelial dysfunction in patients receiving peritoneal dialysis

BACKGROUND

Endothelial dysfunction, which contributes to atherosclerosis and arteriosclerosis, commonly accompanies end-stage renal disease (ESRD). However, little is known about the role of residual renal function (RRF) in endothelial protection in ESRD patients. This study aimed to investigate the relationship between endothelial function and RRF in patients undergoing peritoneal dialysis (PD).

METHODS

This was a cross-sectional study involving 72 prevalent PD patients. Demographic and clinical data were recorded and residual glomerular filtration rate (GFR), Kt/V urea, and serum concentrations of inflammatory markers were measured. Endothelial function was assessed by brachial artery endothelium-dependent vasodilation [flow-mediated dilation (FMD)] to reactive hyperemia following 5 minutes of forearm ischemia.

RESULTS

In patients with FMD% above the median value (FMD > 2.41%), residual GFR was significantly higher compared to that in patients with FMD% below the median [1.50 (0 - 9.64) vs 0.48 (0 - 3.89) mL/min/1.73 m(2), P = 0.026]. Correlation analyses revealed that residual GFR (ρ = 0.381, P = 0.001) and total Kt/V urea (γ = 0.408, P < 0.001) were positively correlated with FMD%, whereas PD duration (γ = -0.351, P = 0.003), high-sensitivity C-reactive protein (ρ = -0.345, P = 0.003), pulse pressure (γ = -0.341, P = 0.003), and age (γ = -0.403, P < 0.001) were inversely correlated with FMD%. In contrast, there was no correlation between peritoneal Kt/V urea and FMD%. In multivariate linear regression analysis adjusted for these factors, residual GFR was found to be an independent determinant of FMD% (β = 0.317, P = 0.017).

CONCLUSION

This study shows that RRF is independently associated with endothelial dysfunction in ESRD patients on PD, suggesting that RRF may contribute to endothelial protection in these patients.

Association between arterial stiffness and peritoneal fluid kinetics

BACKGROUND

A high peritoneal transport status in continuous ambulatory peritoneal dialysis (CAPD) patients is associated with a markedly increased morbidity and mortality. While the causes are as yet unknown, overall the proportion of deaths due to cardiovascular disease is estimated at 40-50% among dialysis patients. Arterial stiffness has been established as a cardiovascular risk factor, while the links between peritoneal transport status and aortic stiffness have not yet been investigated.

METHODS

We included 65 prevalent CAPD patients (24 males/41 females) from our center in a cross-sectional study. Arterial stiffness was assessed by brachial pulse pressure (PP) and carotid-femoral pulse wave velocity (C-F PWV). The patients' peritoneal fluid transport was assessed by kinetic modeling. The patients' peritoneal small solute transport rate was assessed by D/P(cr) at 4 h. Extracellular water to total body water (E/T) ratio was assessed by means of bioimpedance analysis. C-reactive protein was also measured.

RESULTS

C-F PWV was positively correlated with patients' age (r = 0.489, p < 0.01), diabetic status (r = 0.327, p < 0.01), peritoneal fluid absorption rate (Ke; r = 0.251, p < 0.05), PP (r = 0.483, p < 0.01), and E/T (r = 0.517, p < 0.01). Multivariate regression analysis showed that C-F PWV was independently related to E/T (p < 0.01), PP (p < 0.01), age (p < 0.05), and Ke (p < 0.05).

CONCLUSION

Peritoneal fluid transport (Ke), as well as E/T, age and PP were found to be independent predictors of elevated C-F PWV in CAPD patients, suggesting that there might be a link between high aortic stiffness and increased Ke rate, hypothetically through generalized vasculopathy.