CARDIOVASCULAR JOURNAL OF AFRICA • Volume 33, No 5, September/October 2022 AFRICA 251 associated with access dysfunction as it poses a major threat to access circuit patency. Several variations in surgical technique have been described in the literature, including transposition, elevation and superficialisation of the basilic vein. Currently, no level one evidence exists to promote one technique above another. However, in our unit, we try to limit the proximal extent of the incision to allow for easier dissection during open revision of swing segment stenosis or subsequent brachio-axillary AV graft creation. The incision is made approximately 1 cm posterior to the bicipital groove to avoid scar tissue overlying the AVF when a simple elevation or superficialisation is performed. The confluence of the basilic and brachial vein is preserved where possible and a gradual transition from tunnel to native position is ensured by performing a relatively conservative transposition or simple elevation of the basilic vein. In patients with no further superficial AVF option available, the creation of a prosthetic AV graft has some advantages over BBAVF. Generally speaking, they are technically easier to create, especially in obese patients, and can be punctured earlier than BBAVF. Some authors have promoted the use of forearm prosthetic loop grafts above BBAVF, as maturation of the basilic vein (when used as the outflow vein) may facilitate secondary BBAVF creation after graft failure.9 However, when AV grafts become dysfunctional or fail, it is often due to neo-intimal hyperplasia at the graft–vein interface. Therefore, maintenance or salvage procedures (open surgical and endovascular) aimed at addressing these stenoses may encroach on the basilic vein and compromise future ipsilateral BBAVF creation. BBAVF have several advantages over AV grafts, including a lower risk of infection and thrombosis. A meta-analysis comparing one-year primary and secondary failure rates of BBAVF versus prosthetic AV grafts indicated no difference in the outcome between the two groups.10 However, there was a higher re-intervention rate for AV grafts (0.54 per BBAVF vs 1.32 per graft). In a subgroup analysis including two studies, forearm grafts had a three-fold increased risk of failure at one year compared to BBAVF (odds ratio = 0.3, p < 0.0004). A direct cost comparison between AV grafts and BBAVF has not been performed to date. However, in a North American cohort, the average access-related monthly cost associated with AV grafts was significantly higher than that of AVFs (USD 2 656 and USD 1 699, respectively).11 In our series, the primary patency rates at 30 days, and one and three years were 95.1, 48.8 and 19.5%, respectively. Assisted primary patency rates at 30 days, and one and three years were 100, 67.7 and 24.3%, respectively. Secondary patency rates at 30 days, and one and three years were 100, 70.3 and 27%, respectively. Notably, the three-year patency rates achieved were relatively modest, possibly due to the low number of procedures performed to maintain (nine procedures) or re-establish (three procedures) adequate access flow. Fig. 2. Histograms depicting time (in days) from AVF creation to first use (A) and catheter removal (B). A B
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