Improvement of cardiac function by dry weight optimization based on interdialysis inferior vena caval diameter.

In hemodialysis (HD) patients, the diameter of the inferior vena cava (IVC) serves for evaluation of the amount of body fluid. IVC measurement is usually performed immediately before and/or after an HD session. In the present study, we examined the validity of IVC diameter in the interdialysis period (interdialytic IVC) for dry weight (DW) optimization. In 100 HD patients, interdialytic IVC was measured ultrasonographically. The average maximum IVC diameter during quiet expiration (IVCe) was 14.2+/-3.8 mm. In 32 patients with volume dependent hypertension, the interdialytic IVCe was > 16 mm in 29 of 32. Thus, we defined an interdialytic IVCe > 16 mm as a hypervolemic state. Next, by screening 306 HD patients ultrasonographically, 31 patients with left ventricular volume overload were chosen based on criteria of an interdialytic IVCe > 16 mm, together with a left ventricular ejection fraction (EF) < 55%. After the DW was lowered to obtain an interdialytic IVCe < 16 mm, 25 of the 31 patients had a significant increase in EF, decrease in diastolic left ventricular dimension, and amelioration of hypertension. In conclusion, interdialytic IVCe is considered to be a useful parameter for DW optimization. In hypervolemic patients with IVCe > 16 mm, reduction in DW is expected to improve volume overload and cardiac function.