A comparison of preoperative and intraoperative vein mapping sizes for arteriovenous fistula creation

Abstract

BackgroundDuplex ultrasound (DUS) mapping of the veins and arteries of the upper extremity is a well-established practice in arteriovenous fistula creation for long-term hemodialysis access. Previous publications have shown that vein diameters varying from 2 to 3 mm are predictive of success. Regional anesthesia is known to result in vasodilation and thus to increase the diameter of upper extremity veins. This study compares the sizes of veins measured by preoperative DUS mapping with those obtained after regional anesthesia to determine whether intraoperative DUS results in increased vein diameters and thus changes in the operative plan. A second goal was to determine whether such changes resulted in functional access. MethodsThis was a prospective observational study conducted between July 2013 and December 2014. Consecutive patients were preoperatively mapped and then intraoperatively mapped after administration of a regional anesthetic. Comparison of vein mapping sizes and comparison of preoperative plan and operative procedure based on the preoperative and intraoperative DUS mapping, respectively, were analyzed with a repeated-measures linear model. Significance testing was two sided, with a significance level of 5%. ResultsSixty-five patients with end-stage renal disease underwent placement of arteriovenous access with preoperative and intraoperative DUS mapping after regional anesthesia. Comorbidities were representative of the vascular population. After regional anesthesia, intraoperative mid forearm and distal forearm cephalic veins were significantly larger than their respective preoperative measurements. Average increase in diameter of the mid forearm cephalic vein and distal forearm was 0.96 mm (P < .001) and 0.50 mm (P = .04), respectively. There was a significant difference in the number and configuration of arteriovenous accesses (P < .0001). There was more than a twofold significant increase in radial artery-based access procedures concomitant with a significant reduction of brachial-based access procedures and a reduction in graft access procedures. Overall functional access rate was 63%, and patency rates were comparable to those reported in the literature. ConclusionsThe routine use of intraoperative DUS mapping after regional anesthesia is recommended to determine the optimal access site for chronic hemodialysis access. Identifying additional access options not seen with physical examination and preoperative DUS mapping will provide end-stage renal disease patients with more fistula options and hence a longer access life span for a lifelong disease.