Does regional compared to local anaesthesia influence outcome after arteriovenous fistula creation ? One year follow-up of a randomised controlled trial.
E Aitken1, A Jackson1, R Kearns2,3, J Kinsella3, M Clancy1, A Macfarlane2,3
1. Department of Renal Surgery, Queen Elizabeth Hospital, Glasgow. 2. Department of Anaesthesia, Glasgow Royal Infirmary. 3. University Section of Anaesthesia, Pain and Critical Care Medicine, University of Glasgow.
Arteriovenous fistulae (AVF) are the optimal form of vascular access but these have a high early failure rate. Although regional compared to local anaesthesia produces vasodilation and increases short-term blood flow there is no evidence that anaesthesia modality influences long-term fistula patency. This study investigated whether regional compared to local anaesthesia improved long-term AVF patency. The early (3 month) patency rates were recently published in The Lancet.1 1 year follow-up data is now presented.
Materials and Methods
An observer-blinded randomised controlled trial was performed at three university hospitals in Glasgow, UK. Following ethical approval (West of Scotland research Ethics Committee 5 [12/WS/0199]) and informed consent adults undergoing primary radiocephalic (RCF) or brachiocephalic (BCF) AVF creation were randomly assigned (1:1; in blocks of eight) using a computer-generated allocation system to receive either local anaesthesia (LA) or regional (brachial plexus block [BPB]) anaesthesia. Exclusion criteria included coagulopathy, localised infection, neurological disorder or significant neuropathy, no suitable vessels or a previous failed ipsilateral fistula. The primary end point was AVF patency at 3 months. Secondary end points included functional patency at 3 months and 1 year, as well as vessel diameters and brachial artery blood flow before and after anaesthesia. The trial was prospectively registered with ClinicalTrials.gov (NCT01706354).
163 patients were assessed for eligibility and 126 patients were randomly assigned to BPB (n=63) or LA (n=63). All patients completed follow-up on an intention-to-treat basis. BPB but not LA resulted in venodilatation and significantly increased brachial artery blood flow. Primary patency at 3 months was higher in the BPB group than the LA group (53 [84%] vs 39 patients [62%]; odds ratio [OR] 3·3, p=0·005) and was greater in RCF (20 [77%] vs 12 patients [48%]; OR 3·6, p=0·03) but not BCF. During the 1 year follow up period revisional procedures aimed at improving functional patency were performed where possible. Significantly more procedures were possible in the BPB group compared to the LA group (18 procedures on 14 patients vs 6 procedures on 5 patients; p=0.005). Functional patency at 1 year was higher in the BPB group compared to the LA group (51 [81%] vs 35 patients [56%]; OR 3·4, p<0.001), and was greater in RCF (22 [85%] vs 11 patients [44%]; OR 7.0, p=0·004) but not BCF (Table 1).
BPB significantly improved 3 month primary and functional patency and 12 month functional patency rates. This difference was more marked in RCF. Following maturation and revisional procedures the low 3-month functional patency rates observed in our previously published data have significantly improved in the 1 year follow-up data. To our knowledge this is the first randomised trial to show a functional, surgical outcome benefit 1 year following surgery related simply to the choice of anaesthetic. We would advocate that BPB rather than LA is the anaesthetic technique of choice for all primary AVF.