RESUMEN
BACKGROUND: Volume overload is one of the most important, correctable factor for blood pressure control in hemodialysis patient. But objective parameter for the ideal body weight is not available in clinical field yet. Recently inferior vena caval examination became a possible candidate for an objective parameter for intravascular volume status. Therefore we investigated how inferior vena cava changes during hemodialysis compared with total amount of ultrafiltration and ANP, and also the effect of changes of IVC diameter on LVH. METHODS: 43 patients on stable maintainance hemodialysis were enrolled. Among them, 21 patients were on antihypertensive medication. Just before and after the hemodialysis, inferior vena cava diameter, plasma atrial natriuretic peptide and left ventricular mass index were measured for each patient. Inferior vena cava was examined at the level just below the hepatic vein during quiet respiration and left ventricular mass index was calculated. RESULTS: Inferior vena cava at expiration (IVCe) was significantly decreased during hemodialysis (before hemodialysis 21.9 4.9 mm, after hemodialysis 18.3 4.4 mm, p = 0.02). Collasibility index was significantly increased during hemodialysis (before hemodialysis 0.24 0.15, after hemodialysis 0.41 0.19, p < 0.001). Atrial natriuretic peptide (ANP) was significantly decreased during hemodialysis (before hemodialysis 252.3+/-119.0 pg/ml, after hemodialysis 185.6+/-93.2 pg/ml, p<0.001). Total ultrafiltration amount was significantly correlated with collapsibility change (r = - 0.40) and change of ANP (r = -0.41). Left ventricular mass index was correlated with interdialysis weight gain (r=0.39, p<0.05), IVCe after hemodialysis (r=0.48, p < 0.05) in univariate analysis but not in multivariate analysis. CONCLUSION: Collapsibility index of inferior vena cava, IVC diameter and ANP changes reflect the volume change during the hemodiaylsis. Therefore IVC examination can be an objective parameter for volume change during hemodialysis. Postdialysis IVCe correlates weakly with left ventricular mass index but it cannot be an independant risk factor for left ventricular hypertrophy in our study.