Interscalene nerve block for endovascular treatment of brachiocephalic arteriovenous fistula: A pilot study

Percutaneous transluminal angioplasty (PTA) of brachiocephalic arteriovenous fistulas (BC AVF) can be painful, particularly during balloon dilatation of cephalic arch or outflow vein. This study evaluated the effectiveness and safety of interscalene nerve block (ISB) for analgesia during endovascular treatment of BC AVFs.

We retrospectively reviewed 22 endovascular procedures in 21 patients with dysfunctional BC AVFs (March-September 2025) at our institution. All procedures were performed under ISB, with 13 (59%) also receiving supplementary supraclavicular cutaneous nerve block (SCNB). Pain during balloon inflation of the culprit stenosis was assessed using the visual analogue scale (VAS), serving as the primary endpoint of the study. Secondary endpoints included sedative requirements and factors associated with lower pain scores.

The mean patient age was 72 years, and 14 patients (67%) were female. The median VAS score was 2 (0-3) with most procedures resulting in no pain (32%) or mild pain (59%). Sedative use was significantly reduced compared with patients' prior procedures without nerve blocks (midazolam reduction: 1.2 ± 0.8 mg, 95% CI [0.8, 1.6], p < 0.001; fentanyl reduction: 28 ± 16 µg, 95% CI [20, 36], p < 0.001). Combined ISB and SCNB provided superior analgesia compared with ISB alone (median VAS: 1.5 (0-2) vs 3 (2-5), 95% CI of the difference [0.2, 3.2], p < 0.05) when the culprit stenotic lesion was in the shoulder/clavicular region. Higher local anaesthetic volumes correlated with lower pain scores (p < 0.001). No block-related complications occurred, and all patients had full recovery of sensory and motor function within 4 hours.

ISB, with or without SCNB, offers safe and effective analgesia for endovascular treatment of BC AVFs, significantly reducing pain and sedative needs. It may be a useful alternative to systemic sedation, particularly for patients at higher risk from sedative medications.