CARDIOVASCULAR JOURNAL OF AFRICA • Volume 33, No 5, September/October 2022 250 AFRICA One patient presented with a wound seroma that resolved spontaneously over time, and two patients presented with a sensory neuropraxia of the medial forearm (most likely due to a traction injury to the medial cutaneous nerve to the forearm) that had recovered completely by six weeks. In four of the 41 patients, the BBAVF failed to reach maturation. In the remaining 37 patients, the interval (in days) from creation to first use was documented, as well as the interval from first use to catheter removal. The median interval from creation to use was calculated to be 46 days (IQR 38–51). The median interval from first use to catheter removal was calculated as 25 days (IQR 18–29). The median interval from BBAVF creation to catheter removal was 73 days (IQR 57–79) (Fig. 2). Discussion The clinical scenario where superficial AV fistula sites have been exhausted or where the target vessels have been assessed as unsuitable for AV access, creation is not uncommon, particularly in those who have spent years (and often decades) on haemodialysis. Several AV access options have been described to facilitate haemodialysis in this specific subset of patients, potentially negating or delaying the need for tunnelled haemodialysis catheters (THCs) and the complications associated with its use. Clinical practice guidelines from several international vascular access societies have endorsed the use of transposed BBAVF above AV grafts (including forearm loop and brachio-axillary grafts) due to superior outcomes.4-6 However, the recently updated National Kidney Foundation Kidney Disease Outcomes Quality Iniative (NKF-KDOQI) guidelines have emphasised the importance of establishing a patient-centred ESKD life plan and have called on clinicians to individualise the selection of access options according to the patient’s needs, as well as dialysis access eligibility.4 Therefore, it may be appropriate for selected patients to be offered a THC as definitive access (life expectancy less than a year, expected living donor transplant within three months) and for others to be offered an AV graft (elderly, life expectancy less than two years, patient preference). However, for the majority of patients with no superficial AVF option, a transposed BBAVF should be considered. As opposed to the superficial veins, the basilic veins are positioned deep in the fascia and are protected from damage due to repeated venepuncture, making it desirable as a haemodialysis conduit. In most patients, the basilic vein is a large and compliant vessel that enables the creation of a technically simple end-toside anastomosis with the brachial artery. In addition, only one anastomosis is necessary as the anatomical continuity of its venous outflow with the axillary vein is maintained and therefore a potential area of venous anastomotic stenosis is avoided. Due to its deep position and relatively close proximity to the neurovascular bundle, the basilic vein needs to be transposed to ensure safe and repetitive cannulation. Transposition may be performed as a one- or two-stage procedure. The most recent meta-analysis on the topic included three randomised, control trials (including 126 patients) which reported that failure of two-stage BBAVF were less likely to occur than one-stage BBAVF (risk ratio 0.27; p = 0.02).7 Complication rates were similar (risk ratio 0.80; p = 0.54), but two-stage BBAVF were less likely to lose their functional secondary patency compared to one-stage BBVF (risk ratio 0.61; p = 0.11). Therefore, there is evidence to suggest that two-stage BBAVF may achieve higher maturation rates compared to one-stage BBAVF, but the evidence for a difference in long-term secondary patency is less robust, calling for further research.7 The segment of transposed basilic vein, just before its confluence with the brachial vein, is considered a high-risk segment for stenosis, also referred to as the swing segment. Turbulent blood flow as a result of the curvature of the vessel at this point results in altered shear stress, which is treated when Cumulative patency (%) Fig. 1. Kaplan–Meier analysis of BBAVF patency rates at one, two and three years.
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