CARDIOVASCULAR JOURNAL OF AFRICA • Volume 33, No 5, September/October 2022 AFRICA 249 Assisted primary patency was defined as the interval from access creation to first thrombosis (thrombosis-free interval). Secondary patency was defined as the interval from access creation to access abandonment. Patency rates were censored for the following events: transfer to peritoneal dialysis, transplant, loss to follow up, and death. The last date of patency assessment (end-date) was 24 April 2020. Both one- and two-stage procedures were performed during the study period. The first stage of the two-stage procedure was performed under local anaesthesia through a 3–4-cm longitudinal incision in the region of the distal bicipital groove. An end-to-side anastomosis of the basilic vein to the brachial artery was performed. Four weeks after the first-stage procedure, an ultrasonographic assessment of maturation was performed. Once maturation had been confirmed, the second-stage procedure was performed under general anaesthesia. A 12–15cm longitudinal incision was made 1 cm posterior to the bicipital groove, limiting the proximal extent of the incision as much as possible. The brachial fascia was incised and the arterialised outflow vein was identified and dissected from its bed by ligation and division of all tributaries up to the point of confluence with the brachial veins, while preserving the medial cutaneous nerve branches to the forearm. The mobilised vein was elevated, divided distally and tunnelled laterally with a gentle curve, followed by an end-to-end re-anastomosis. The one-stage procedure followed the same principles described in the second stage of the two-stage procedure, without the need to divide and re-anastomose the basilic vein, as a direct end-to-side anastomosis of the basilic vein to the brachial artery was performed. Patients were evaluated at 72 hours post procedure for early complications. Thereafter, cannulation readiness was assessed on a weekly basis through physical examination and duplex ultrasound. Once cannulated, patients were assessed periodically for complications. Dialysis catheters were removed once the BBAVF were cannulated with two needles for two consecutive weeks without incident. Surveillance of the BBAVF was not performed. Instead, access was monitored for signs of dysfunction and selectively interrogated with duplex ultrasound as an adjunct to physical examination. Interventions (both open and endovascular) were performed for dysfunctional access. Thrombosed BBAVF were considered for surgical thrombectomy if referred within 72 hours of thrombosis. Statistical analysis Quantitative data were collected and analysed using Stata/SE version 13.1 (StataCorp®, College Station, Texas). Descriptive statistics were used to summarise patient characteristics, functional outcomes, complications and patency. Continuous variables are summarised as median with interquartile range (IQR) if distribution was skewed. Categorical outcome variables, including functional outcomes, complications and patency are expressed as frequencies and percentages per specified time point. The duration of fistula patency and median fistula survival time were estimated using the Kaplan–Meier method and illustrated using Kaplan–Meier survival curves. Survival probabilities at 30 days, and one and three years are presented with 95% confidence intervals (CI). Results From 1 January 2014 to 24 April 2020, a total of 41 BBAVF were created and followed up in 41 prevalent haemodialysis patients at our facility. The median age of the patients was 45 years (IQR 32–54). Twenty females and 21 males were included in the study (Table 1). The following baseline characteristics were reported at the time of BBAVF creation. The median cumulative days on haemodialysis was calculated as 1 343 days (IQR 828–2 920). The median cumulative days with the dialysis catheter in situ was calculated as 704 days (IQR 348–1 460). All BBAVF procedures were performed in prevalent haemodialysis patients and therefore no pre-emptive BBAVF were performed. Two patients had not undergone previous attempts at peripheral AV access, with 137 previous attempts made in the remaining 39 patients. Nineteen of the 41 patients (46.3%) had a previous attempt at brachio-axillary AV graft creation. A pre-existing (failed) ipsilateral brachio-axillary AV graft was present in 12 of 41 patients (29.3%) who ultimately underwent BBAVF creation. Of the 41 BBAVF that were performed, 24 (58.5%) were performed as a one-stage procedure and 17 (41.5%) as a two-stage procedure. Of the 17 first-stage procedures performed, all 17 reached maturity and could either be transposed (n = 14) or elevated (n = 3) during the second-stage procedure. All firststage procedures were performed under local anaesthesia, while all other (second- and one-stage) procedures were performed under general anaesthesia (Table 1). The primary patency rates at 30 days, and one and three years were 95.1% (95% CI: 81.9–98.8), 48.8% (95% CI: 32.9–62.9) and 19.5% (95% CI: 9.2–32.7), respectively. Assisted primary patency rates at 30 days, and one and three years were 100, 67.7 (95% CI: 50.0–80.1) and 24.3% (95% CI: 12.1– 38.8), respectively. Secondary patency rates at 30 days, and one and three years were 100, 70.3 (95% CI: 52.8–82.3) and 27% (95% CI: 14.1–41.8), respectively (Fig. 1). Of the 41 patients who underwent BBAVF creation, four (9.8%) presented with minor complications within 30 days. One patient developed minor wound dehiscence that ultimately healed without the need for surgical intervention, possibly due to an element of unrecognised pre-existing central vein stenosis. Table 1. Demographic and baseline characteristics of 41 patients who underwent BBAVF creation Characteristics Number and IQR or percent Median age, n (IQR), years 45 (32–54) Male:female 21:20 Median cumulative haemodialysis days, n (IQR) 1 343 (828–2 920) Median cumulative haemodialysis catheter days, n (IQR) 704 (348–1 460) Previous attempts at peripheral AV access, n (%) 6 5 4 3 2 1 0 2 (4.9) 7 (17.1) 9 (22) 13 (31.7) 7 (17.1) 1 (2.4) 2 (4.9) Previous ipsilateral attempt at BAAV graft, n (%) 12 (29.3) One-stage procedure, n (%) Two-stage procedure, n (%) 24 (58.5) 17 (41.5) IQR, interquartile range; BAAV, brachio-axillary arteriovenous.
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