MO721: Correlation of Serum BNP Levels with Blood Pressure Variability using ABPM in Patients NAÏVE on Haemodialysis
Authors: Yadla Manjusha , Khandalvalli Pradeep 
Published: May 2022

Abstract

BACKGROUND AND AIMS
Plasma BNP levels are thought to correlate with blood pressure monitoring in patients on maintenance haemodialysis. An adequate BP control results in decline in mortality rates in these patients.
To correlate plasma BNP levels and blood pressure variability using ABPM with echocardiographic findings in non-hypertensive patients with end-stage renal disease naïve on haemodialysis.

METHOD
Type of study: Institutional-based, a single-centre cross-sectional observational study.
Study period : January 2017–2019.
Sample size: 80.

RESULTS
In our study, 75% were males and 25% were females. Out of 80 patients type 2 diabetes mellitus was present in 13 (16.3%), hypertension was present (based on office BP) in 36 (45%), 86.3% of patients had azotemia symptoms at presentation, 72.5% of patients were underweight (BMI &lt; 18.5 kg/m2), 42.5% of patients were categorized as CKD G5A3, hyperuricemia was present in 31.3%. Mean age was 47.6 years, mean height was 165 cm, mean weight was 47.8 kg, mean BMI was 17.54 kg/m2 mean SBP was 129.10 mmHg and mean DBP was 78.05 mmHg.
During passive phase ABPM readings, double product was low in 50% of cases, HBI diagnosed hypertension and isolated systolic hypertension, isolated diastolic hypertension in 62.3%, 11.3% and 3.8% of cases, respectively. ABPM diagnosis of non-hypertension or hypertension under control was observed in 22.55 of cases during passive phase. Mean total cholesterol was significantly more in HTN compared with patients without HTN; P &lt; 0.05. Mean BNP was significantly higher in patients with HTN compared with patients without HTN; P &lt; 0.05.
There was a significant negative correlation observed between BNP and EF on 2D ECHO, LVH on 2D ECHO and EF (%) on 2D ECHO; P &lt; 0.05. No factor was found to be associated statistically significant with outcome. Comparison of mean BNP levels in relation to dipping status on ABPM in all six groups i.e. HTN group containing three subgroups (non-dippers, normal dippers and reverse dippers) and non-HTN group containing three subgroups (non-dippers, normal dippers and reverse dippers) did not reveal any significance (P &gt; 0.05).
Comparison of mean BNP levels in relation to dipping status on ABPM in all six groups, i.e. HTN group containing 3 subgroups (non-dippers, normal dippers and reverse dippers) and non-HTN group containing three subgroups (non-dippers, normal dippers and reverse dippers) did not reveal any significance (P &gt; 0.05).
ABPM readings diagnosed underlying masked hypertension in 19 out of 44 (43.1%) patients with normal office BP readings. Subgroup analysis of plasma BNP relation to this masked hypertension patients and actual non-hypertension patients also did not reveal any significant difference in plasma BNP levels (ROC—best cut-off of 23.05 ng/L with sensitivity of 88% and specificity of 26.3%).

CONCLUSION
ABPM is useful to diagnose significant number of masked hypertension patients in those naïve on dialysis.
Plasma BNP level has a low sensitivity and specificity as a screening tool to identify dipping status or to predict outcomes in ESRD patients naïve to haemodialysis.