Pre-operative Patient Specific Flow Predictions to Improve Haemodialysis Arteriovenous Fistula Maturation (Shunt Simulation Study): A Randomised Controlled Trial

Abstract

WHAT THIS PAPER ADDS Arteriovenous fistula (AVF) maturation remains a permanent issue in vascular access surgery for haemodialysis treatment. Numerous studies have tried to improve clinical decision making or predict maturation probability. The present study shows that a new and innovative patient specific computation model accurately calculates postoperative access flows, and as flow is related to maturation, this model may potentially improve AVF maturation rates.Objective: An arteriovenous fistula (AVF) needs to mature before it becomes suitable to cannulate for haemodialysis treatment. Maturation importantly depends on the post-operative flow increase. Unfortunately, 20e40% of AVFs fail to mature (FTM). A patient specific computational model that predicts immediate postoperative flow was developed, and it was hypothesised that providing information from this model for planning of fistula creation might reduce FTM rates. Methods: A multicentre, randomised controlled trial in nine Dutch hospitals was conducted in which patients with renal failure who were referred for AVF creation, were recruited. Patients were randomly assigned (1:1) to the control or computer simulation group. Both groups underwent a work up, with physical and duplex ultrasonography (DUS) examination. In the simulation group the data from the DUS examination were used for model simulations, and based on the immediate post-operative flow prediction, the ideal AVF configuration was recommended. The primary endpoint was AVF maturation defined as an AVF flow !500 mL/min and a vein inner diameter of !4 mm six weeks post-operatively. The secondary endpoint was model performance (i.e. comparisons between measured and predicted flows, and (multivariable) regression analysis for maturation probability with accompanying area under the receiver operator characteristic curve [AUC]). Results: A total of 236 patients were randomly assigned (116 in the control and 120 in the simulation group), of whom 205 (100 and 105 respectively) were analysed for the primary endpoint. There was no difference in FTM rates between the groups (29% and 32% respectively). Immediate post-operative flow prediction had an OR of 1.15 (1.06e1.26; p < .001) per 100 mL/min for maturation, and the accompanying AUC was 0.67 (0.59e0.75). Conclusion:Providing pre-operative patient specific flow simulations during surgical planning does not result in improved maturation rates. Further study is needed to improve the predictive power of these simulations in order to render the computational model an adjunct to surgical planning.

Surgical planning of arteriovenous fistulae in routine clinical practice: A machine learning predictive tool

“…Finally, as for the AVF non-maturation, the obtained confusion matrix confirmed the high accuracy of the predictions, equal to 96.8%, significantly higher than the NIR. Our tool also allows to easily evaluate the impact of VA characteristics on maturation, BFVs and diameters, as in other works, 21 thanks to the inclusion of predictor type, which summarizes AVF location and configuration. When a new patient is analyzed, the output variables can be predicted considering their characteristics and the different alternatives for VA type.…”

The use of AVF.SIM system for the surgical planning of arteriovenous fistulae in routine clinical practice

“…However, they do not allow to preoperatively predict BFV in the AVF at maturation. Zonnebeld et al 24 recently reported the results of the Shunt Simulation Study, the clinical validation of a computational model able to predict the immediately postoperative AVF flow starting from preoperative data. As shown by the authors, the model performance was satisfactory, but its use did not improve AVF maturation in the simulation group as compared to the control group.…”

VAVASC study: Clinical trial protocol

“…Prediction models for AV access have been proposed in several studies before. [5][6][7] One of the most notable studies is the 'Shunt Simulation Study', where the authors aimed to validate a prediction model for AV maturation based on preoperatively calculated flow simulations. Unfortunately, the study did not validate the desired outcome, which was an increased number of matured AVFs.…”