Development of a prognostic model for fistula maturation in patients with advanced renal failure

• Main Author: Siddiqui, Muhammad A.
• Published: Queen Margaret University 2014
• Subjects: 617.5; Podiatry
• Online Access: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.674894

Introduction: A suitable type of vascular access has to be created to establish a connection between the circulation system of the patient and the haemodialysis cycle. The arteriovenous fistula (AVF) is considered to provide the best long-term functional vascular access, with reduced risk of thrombosis or infection and cost-effective. However, significant numbers of AVF, which fail to develop sufficiently for dialysis, are 28-53% of cases. This study aimed to explore the potential influence of blood markers and factors on the maturation of AVF, in patients who have undergone vascular access surgery and to develop and validate a prognostic model to determine the success of AVF maturation. Methods: Data from 300 patients was retrieved who had undergone AVF surgery between the years 2006 and 2009, from the Royal Infirmary of Edinburgh. A prognostic model was developed for the prediction of maturation of AVF using backward stepwise logistical regression. This data was analysed using univariable, multivariable logistic regression. Model performance was assessed, using the receiver operating characteristics (ROC) curve and Hosmer and Lemeshow goodness of fit test. A prognostic model was validated with the prospective data of 100 patients who had undergone AVF surgery between the years 2009 and 2011, from the Royal Infirmary of Edinburgh. Results: Three variables were identified, which independently influenced fistula maturation. Males were twice as likely to undergo fistula maturation, compared to that of females (odds ratio (OR) 0.514; 95% confidence interval (CI) 0.308 to 0.857). Patients with no evidence of Peripheral Vascular Disease (PVD) were three times more likely to mature their fistula (OR 3.140; 95% CI 1.596 to 6.177). A pre-operative vein diameter greater than 2.5mm resulted in a fivefold increase in fistula maturation compared to a vein size less than 2.5mm (OR 4.532; 95% CI 2.063 to 9.958). The model for fistula maturation had good discrimination as indicated by area under the ROC curve 0.677 and calibration as indicated by Hosmer and Lemeshow test (p = 0.79). The model discriminatory power was confirmed in the prospective study (validation data set) with area under the receiver operating curve was 0.59 and calibration indicated by Hosmer and Lemeshow test (p > 0.05). Conclusion: Successful vascular access provision is the foundation on which successful haemodialysis is built. This study has found that female gender, history of PVD and vein diameter less than 2.5 mm are the negative significant independent clinical predictors of maturation of arteriovenous fistula.