Prediction of vascular access stenosis: Blood temperature monitoring with the Twister versus static intra-access pressure ratio

Abstract

BackgroundThe Kidney Disease Outcomes Quality Initiative (KDOQI) guidelines recommend intra-access flow (Qa) measurement as the preferred vascular access surveillance method over static intra-access pressure ratio (SIAPR). Recently, it has become possible to perform Qa measurement during hemodialysis using thermodilution method called blood temperature monitoring (BTM) with the Twister device. The aim of this study was to investigate the correlation between Qa by BTM and SIAPR and to compare the performance of two tests in prediction of vascular access stenosis.MethodsThe study was performed from January 2016 to November 2017 and included 97 patients with arteriovenous fistulas (AVF). Qa by BTM and SIAPR were simultaneously measured every 1~3 months with a total of 449 measurements during study period.ResultsIn our study population, mean age was 59.9±10.0 years and 61.9% were diabetes. The mean Qa obtained by BTM was 1186±588 mL/min. There was no correlation between Qa by BTM and venous SIAPR (r = 0.061, P = 0.196). Angiography identified 36 stenotic AVFs (37.1%) among the study subjects. They included 13 cases with only inflow stenosis, 6 with only outflow stenosis, and 17 with stenosis on both sides. Receiver-operating characteristic (ROC) curve analysis showed that Qa by BTM had higher discriminative ability to diagnose vascular access stenosis compared to SIAPR (P <0.001). The Qa less than 583 mL/min showed the highest diagnostic accuracy in vascular stenosis prediction.ConclusionIntradialytic measurement of Qa by BTM showed better diagnostic power over venous SIAPR in prediction of vascular access stenosis.

Use of blood temperature monitor with Twister device for the surveillance of vascular access in maintenance hemodialysis: Comparison with Doppler ultrasonography

“…10,13,22 However, only two studies using Twister ® in BF measurement have been reported, and the results were not compared with those from DUS. 14,15 Our study showed for the first time that VA BF measured by BTM correlates with the BF measured by DUS. Also, we confirmed that the degree of VA stenosis predicted by the AUC for BTM BF was not inferior to that of DUS.…”

“…However, that group found no correlation between BF measured by BTM and BF measured by the static intra-access pressure ratio method. 14 In a 2012 Spanish study, the correlation coefficient between BF measured by BTM and by the Delta-H method was 0.988. 15 Although the precise coefficients vary from study to study, the results of all showed that BTM could be used as a surveillance method to assess for VA stenosis.…”

“…Twister ® device is an useful surveillance method in maintenance HD, because it does not need additional time, specialized equipment, or specially trained staff. 12,14,15 It measures BF accurately, takes the short time (approximately 5 min), is highly reproducible, and can be measured without interfering with the dialysis schedule. 10,13,22 However, only two studies using Twister ® in BF measurement have been reported, and the results were not compared with those from DUS.…”

“…Several studies of this method have shown very good clinical results in patients on HD. 14,15 The BTM method uses a blood temperature monitor (BTM ® ; Fresenius Medical Care, Bad Homburg, Germany), with standard and reversed positions of the HD lines, recirculation values can be obtained. 13,16 Since the BTM ® sensor is integrated into the HD machine and the line can be easily reversed with the Twister ® (Fresenius Medical Care) device, BF measurement is simple to use and faster than other methods.…”

Stima della portata della fistola artero-venosa mediante termodiluizione nei pazienti in emodialisi cronica: esperienza monocentrica.

“…Il BTM, rispetto al Doppler, non ha costi aggiuntivi, non è operatore-dipendente, si può eseguire durante il trattamento emodialitico senza prolungare il tempo di transito del paziente in ospedale e non richiede attrezzature specifiche che non siano già integrate in alcuni monitor di dialisi. Va inoltre segnalato che la procedura di calcolo del ricircolo a linee invertite è oggi facilitata dall'uso del Twister, un device che consente di invertire le linee del paziente senza disconnetterle manualmente (10).…”