Towards improved cardiovascular management: the necessity of combining blood pressure and fluid overload

Background. Hypertension and fluid overload (FO) are well-recognized problems in the chronic kidney disease (CKD) population. While the prevalence of hypertension is well documented, little is known about the severity of FO in this population. Methods. A new bioimpedance spectroscopy device (BCM-Body Composition Monitor) was selected that allows quantitative determination of the deviation in hydration status from normal ranges (Delta HS). Pre-dialysis systolic blood pressure (BPsys) and Delta HS was analysed in 500 haemodialysis patients from eight dialysis centres. A graphical tool (HRP-hydration reference plot) was devised allowing Delta HS to be combined with measurements of BPsys enabling comparison with a matched healthy population (n = 1244). Results. Nineteen percent of patients(n = 95) were found to have normal BPsys and Delta HS in the normal range. Approximately one-third of patients (n = 133) exhibited reasonable control of BPsys and fluids (BPsys < 150 mmHg and Delta HS < 2.5 L). In only 15% of patients (n = 74) was hypertension observed (BPsys > 150 mmHg) with a concomitant Delta HS > 2.5 L (possible volume-dependent hypertension). In contrast, 13% of patients (n = 69) were hypertensive with Delta HS < 1.1 L (possible essential hypertension). In 10% of patients (n = 52), BPsys < 140 mmHg was recorded despite Delta HS exceeding 2.5 L. Conclusion. Our study illustrated the wide variability in BPsys regardless of the degree of Delta HS. The HRP provides an invaluable tool for classifying patients in terms of BPsys and Delta HS and the proximity of these parameters to reference ranges. This represents an important step towards more objective choice of strategies for the optimal treatment of hypertension and FO. Further studies are required to assess the prognostic and therapeutic role of the HRP.