Access flow (Qa) has an important effect on systemic hemodynamics in dialysis patients. A Qa : cardiac output (CO) ratio higher than 0.3 is considered a risk factor for high-output cardiac failure. However, the effect of different types of vascular access in hemodialysis patients has not yet been studied. The aim of the present study was to assess the relationship between Qa and systemic hemodynamics and to compare systemic hemodynamics between patients with elbow/upperarm access with forearm access types. Qa, CO, cardiac index (CI), central blood volume (CBV), and peripheral vascular resistance (PVR) were studied by the saline dilution technique in 58 hemodialysis patients (18 with elbow/upperarm access; 40 with forearm access types). This article found that Qa was significantly and positively related to CO and CI, and inversely related to PVR. CBV, Qa, and presence of cardiac failure were independent determinants of CI. Qa and the Qa : CO ratio were significantly higher, and PVR significantly lower, in patients with elbow/upperarm access compared to patients with forearm access types. When patients with cardiac failure were excluded, CO and CI were also significantly higher in patients with elbow/upperarm access types. Eleven percent of patients with elbow/upperarm fistula had a Qa : CO ratio above 0.3. In conclusion, Qa is strongly related to systemic hemodynamics in dialysis patients. In patients without cardiac failure, CO and CI are significantly higher in patients with elbow/upperarm access compared to patients with forearm access types. However, only a small percentage of patients with elbow/upperarm fistulae appeared to be in the risk zone for development of high-output cardiac failure.

A quality improvement programme based on periodical access flow measurement reduced the number of acute vascular access failures due to thrombotic events and also significantly reduced health care costs in patients with AVG, but not in patients with AVF. The quality improvement programme had no effect on access survival.

Periodical access flow measurements can predict the development and presence of vascular access flow-limiting stenosis and subsequent thrombosis. Access flow measurement has become a standard in vascular access care. Different techniques to measure access flow are available. The aim of this study was to compare an integrated access flow measurement device, based on thermodilution (Blood Temperature Monitor, BTM, Fresenius Medical Care, Bad Homburg, Germany), with the gold standard, the HD01 (Transonic Systems Inc., Ithaca, NY), whose technique is based on saline dilution. In 40 patients with end-stage renal disease, 40 vascular accesses were studied to determine the correlation between access flow measurements by both techniques. Reproducibility of access flow measurements by both techniques was assessed in 20 patients on a weekly interval.A total of 40 measurement series were performed. Average access flow measured with the saline technique and the thermodilution technique was 1053 (+/-495) ml/min and 1034 (+/-527) ml/min, respectively (p = ns) (n = 40). Correlation between access flow measurements by both techniques expressed in R was 0.79 (r = 0.89). Reproducibility of saline and thermodilution subsequent measurements with a weekly interval, expressed in relative difference (Delta xrel) was 13 (+/-11)% and 24 (+/-14)%, respectively (p < 0.01) (n = 20).BTM access flow measurements correlated well with the HD01 access flow measurements. However, the better reproducibility of HD01 and shorter measurement time compared with BTM access flow measurements should be considered when implementing access flow measurement to prevent vascular access failure.

A reduction in vascular access flow poses a risk for thrombosis. We present a new technique to measure vascular access flow during dialysis based on extracorporeal temperature gradients, and their changes, on reversing the extracorporeal bloodlines without having to inject an indicator. Fistula temperatures were measured by the blood temperature monitor with normal line position and after manual switching of the bloodlines using the same extracorporeal blood flow. The access flow by our temperature gradient method (TGM) was compared to access flow derived by saline dilution with measurements in the same patients repeated in subsequent weeks. In 70 pairs of TGM and saline dilution measurements in 35 patients, the repeatability of the TGM measurements was not significantly different from that of saline dilution. There was a highly significant correlation between the two techniques with an acceptable confidence level for limits of agreement for the difference between them. It took about 9 min to complete the TGM method and about 5 min for saline dilution. Our studies show that the novel TGM method showed excellent agreement and reproducibility with the saline dilution method without the need for indicator dilution.

Brachial artery WSR is normal in accesses older than six years with an increased internal diameter and wall cross-sectional area as compared to "younger" accesses. This suggests a process of vascular remodeling with an increase in vascular wall mass and normalization of WSR to physiologic values at the price of increased mean cross-sectional wall stress.