Abstract
The purpose of this study was two-fold: First, we investigated changes in the internal shunt flow volume (FV) and real blood flow over time in patients during dialysis. Second, we examined possible factors responsible for a reduced FV and real blood flow. A total of 64 patients on maintenance hemodialysis were the subjects of this study, and the observation period was two months. We measured FV, real blood flow, systolic blood pressure, and diastolic blood pressure in the subjects during dialysis at the start, at 1.5 hours, at 2.5 hours, and, at the end of dialysis, examined their variation over time, and analyzed correlations. In order to examine the variation of blood pressure changes, we classified the subjects into two groups: reduced FV group and unchanged FV group. In addition, 14 possible factors contributing to FV changes during dialysis were examined by calculating FV changes in both groups. The differences of time-varying changes of FV in the factors were evaluated. Finally, the rate of shunt venous enlargement was measured in the cases with or without the factors responsible for FV changes. The results indicated that both FV and real blood flow were significantly reduced during dialysis (p<0.001), and a significant positive correlation between them was found (R=0.76). However, no significant correlation was obtained between the blood pressure and FV (R=0.17), and the blood pressure showed a significant decrease with time in the FV unchanged group during dialysis (p<0.001). In consideration of factors reducing FV, shunt vascular calcification, an abnormal ABI, and diabetes showed higher contribution rates, among which shunt vascular calcification was the highest (x2=15.2), suggesting involvement in the reduced venous enlargement of the venous shunt. From these results, it is most likely that the risk factors that decrease FV and real blood flow during dialysis are associated with a decrease in vascular compliance caused by torn shunts and systemic vessels. Since a patient with shunt vessel calcification and/or systemic torn vessels might have shunt blood flow deficiency during dialysis, special consideration of such patients requiring systematic observation for safety during dialysis treatment including shunt management is needed.
