#4470 THE IMPACT OF RESIDUAL NATRIURESIS ON INTRADIALYTIC HYPERTENSION IN PATIENTS ON ISONATRIC DIALYSIS: A MONOCENTRIC STUDY AT THE FRANCK JOLY HOSPITAL CENTER
Authors: Makembi Arriel , Kinika Jenny Manzombi , Mbangi Bijoux , Ebobo Jean Baptiste Mombo , Fermigier Florence , Djiconkpode Irénée 
Published: June 2023

Abstract

Background and Aims
Intradialytic hypertension (IDH) is an elevation of blood pressure recorded during dialysis monitoring and at the end of the session relative to the values recorded at the connection. Hypervolemia and positive sodium balance are the main mechanisms. Isonatric dialysis allows a restoration of natremia corresponding to an optimal state of cellular hydration at the end of the session, and residual natriuresis is related to the state of extracellular hydration. Hence, their potential role in the appearance of IDH. The objective of this study is to measure the impact of residual natriuresis on IDH in patients on chronic isonatric hemodialysis.

Method
Transversal, descriptive and analytical study, having examined 12 last dialysis sessions of December 2023 of 65 patients in chronic hemodialysis (780 dialysis sessions) at the FRANCK JOLY Hospital Center in French Guiana. The primary outcome was the presence of intradialytic hypertension (IDH), defined as a difference in mean blood pressure ≥ 15 mmHg at disconnection from branching, or the need for antihypertensive treatment during the session with as main explanatory variables: residual natriuresis and sodium perdialytic concentration. Welche, Mann Whitney, Fisher and chi2 tests were used in univariate analysis and logistic regression in multivariate analysis to determine factors associated with IDH. The significance threshold was set at: p &lt; 0.005.

Results
The 65 files analyzed had a predominance of women at 55%. 780 dialysis sessions were reviewed, including 206 with IDH, or nearly 1/4 of the sessions. 37% of patients were affected by IDH with a sex ratio of 1. 94% of patients had a history of hypertension and 22% were diabetic. 57% of patients had zero residual diuresis. The average interdialytic weight gain was 2.3 kg. 48% had at least triple antihypertensive therapy. The average duration of a dialysis session was 4 hours, the mean KT/V was 1.2; The mean natremia was 138 mEq/L and the mean perdialytic sodium concentration was 140 mEq/L. The median residual natriuresis was 8.55[0; 26.2] mEq/L. The mean NT-proBNP level was 2407 pg/ml. In univariate analysis, residual natriuresis and perdialytic natremia were not statistically associated with HID. Factors significantly associated with IDH were a number of antihypertensive treatments, NT-proBNP level and duration of dialysis session. In multivariate analysis: the high number of antihypertensive treatments and the increased duration of the dialysis session emerged as risk factors for IDH. Indeed, when the number of antihypertensives increased by 1 unit, the IDH score was multiplied on average by 2.74 (p&lt;0.001), and when the session duration (h) increased by 0.1 units, the IDH score was multiplied by an average of 1.39 (p = 0.019). Residual natriuresis appeared as a protective factor against interdialytic weight gain, because when urinary sodium (mEq/l) increased by 10 units, mean interdialytic weight gain (kg) decreased by an average of -0.116 (p = 0.043).

Conclusion
Intradialytic hypertension is common and multifactorial. Antihypertensive combination therapy, usually reflecting resistant high blood pressure, is a major risk factor. The present study, at the expense of the definition criteria used, did not find significant associations with perdialytic natremia and residual natriuresis. However, the latter remains protective against interdialytic hypervolemia. Hence, the need for its preservation.