Vascular Access

AVF: permanent communication bw a + v → shortcutting microcirculation

• v - increase p, dilatation + elongation

• a - flow decreases distal to anastomosis → ischemia + low p, CO increase

Acquired AVFs in : CKD

Rule of 6 : requirements of mature AVF : v diameter >6mm, velocity @ anastomosis 600ml/min, position v. <6mm depth, suitable for punction length of vein >6cm

Preop evaluation: Duplex US, Allen test for palmar arch evaulation, a + v diameters >2mm, peripheral v circ assessed by tourniquet

Complications: anastomosis hyperplasia, thrombosis, aneurysmal dilatation, a. steal syndrome (hand ischemia)

• treatment

  • stenosis - angioplasty

  • thrombosis - thrombectomy

  • aneurysm - resection or repositioning anastomosis