Associations Between Left Ventricular Hypertrophy and Hydration Status in Hemodialysis Patients
Background and objective: Left ventricular hypertrophy (LVH) is a strong causal risk factor for cardiovascular morbidity and death in end-stage kidney failure. Fluid overload and hypertension are the major causes of left ventricular hypertrophy and failure. The aim of our study was to evaluate a relation between left ventricular hypertrophy in hemodialysis (HD) patients with cardiac biomarker NT-pro-BNP and hyperhydration measured by bioimpedance (BIA) and lung ultrasound (US).
Materials and methods: We performed a one-center cross-sectional study of 36 patients undergoing chronic HD at the Hospital of the Lithuanian University of Health Sciences, Kaunas Clinics.
Echocardiography was conducted for all patients within 1 year before the beginning of the study. The criteria for LVH were left ventricular mass index (LVMI) > 115 g/m2 in men and LVMI > 95 g/m2 in women. The hydration level was evaluated using 2 methods: BIA and lung ultrasound (US). BIA, lung US and plasma NT-pro-BNP levels were tested during September and October 2014. BIA was performed after dialysis, and the volemia status was evaluated according to the ratio of extracellular (ECW) and total body water (TBW). Lung US was performed before and after hemodialysis in 8 points as described in the Blue protocol; extravascular lung water was estimated by calculation of B lines, i.e., the sum of B lines in all points was used in the final analysis.
Results: LVH was detected in 20 patients (56%). Patients with LVH were hyperhydrated on BIA measurement (ECW/TBW ratio 0.39 ± 0.013 vs 0.38 ± 0.01, P = 0.03). They had significantly more B lines on lung US before HD (4.55 ± 4.56 vs 1.94 ± 2.32, P = 0.045), and more than 3 times higher NT-pro-BNP levels before HD (14044.75 ± 10982.95 pg/mL vs 4116.21 ± 4399.42 pg/mL, P = 0.001) and after HD (13164.79 pg/mL ± 11073.65 pg/mL vs 3460.57 ± 4257.54 pg/mL,
P = 0.002) as compared with patients without LVH. Patients with LVH also had higher systolic blood pressure before HD (149.22 ± 17.06 mmHg vs 134.11 ± 14.52 mm Hg, P = 0.02) and after dialysis (144.98 ± 17.16 mm Hg vs 127.61 ± 18 mm Hg, P = 0.015).
Conclusions: Left ventricular hypertrophy was present in more than half of prevalent hemodialysis patients. It was related to hyperhydration detected by bioimpedance and by lung ultrasound. In these patients the level of NT-pro-BNP before and after hemodialysis was more than 3 times higher as compared with those without left ventricular hypertrophy. Further studies are needed for confirmation of causal relation of these associations.
Correspondence to R. Vaičiūnienė Medical Academy, Lithuanian University of Health Sciences, Eivenių 2, LT-50161 Kaunas, Lithuania E-mail address: firstname.lastname@example.org