AV fistula physical exam: thrill, bruit and maneuvers

The physical exam is the cheapest surveillance tool there is, and the one used at every session. Done well, it finds most problems with an arteriovenous fistula before it clots. This guide covers the look, feel and listen sequence, the three maneuvers that tell inflow stenosis, outflow stenosis and an accessory vein apart, the hand exam and which findings need action.

For professionals · Updated November 10, 2026 · 9-minute read

1. Look

With the arm uncovered and relaxed, follow the access from the hand to the shoulder. Look for:

• The skin over the vein: intact, without persistent scabs, redness, warmth or discharge (infection).
• Aneurysms: their size and the skin over them. Thin, shiny, ulcerated or bleeding skin is an emergency (see AV fistula aneurysm).
• Hematomas from previous cannulations.
• Swelling of the arm, hand or face, and collateral veins on the shoulder or chest: these suggest central venous stenosis.
• The hand: its color and any wounds on the fingers (steal).
• Visible accessory veins branching off the main vein.

2. Feel

With your fingertips, without pressing, follow the whole vein from the anastomosis:

• Thrill: the vibration produced by turbulent flow. Normally it is continuous (in systole and diastole), strongest at the anastomosis and fading along the vein [1]. A systolic-only thrill, or a strong thrill at a point far from the anastomosis, indicates a stenosis [1,3].
• Pulse: a healthy fistula is soft and easy to compress, with a gentle pulse. A strong, water-hammer pulse means there is a stenosis further up. A flat fistula that barely fills suggests an inflow problem [3].
• Course, size and depth, hard segments (thrombus, scar) and tender areas.
• Temperature of the skin over the access and of the hand.

3. Listen

With a stethoscope, along the whole course. The normal bruit is continuous and low-pitched, and softer the further you move from the anastomosis [1]. A high-pitched, whistling or systolic-only bruit suggests a stenosis: listen for where the pitch changes, because that is usually where it is [1]. If there is no bruit and no thrill, the fistula may be clotted: it is urgent.

4. The three maneuvers

Arm elevation test: assesses outflow

With the patient seated or supine, raise the arm above the heart. In a normal fistula the vein collapses, at least partly. If a segment stays full and tense, there is an outflow stenosis further up: the segment that does not collapse lies before it and the one that collapses lies after it [3]. It is not useful in grafts, which run at higher pressures [3].

Pulse augmentation test: assesses inflow

Compress the vein with one finger a few centimeters above the anastomosis and feel the pulse between the anastomosis and your finger. With the outflow occluded, the pulse should increase clearly. If it barely changes, there is an inflow stenosis: artery, anastomosis or first segment of the vein [3]. If the vein was already hyperpulsatile before compressing, the problem is in the outflow.

Sequential occlusion: looks for accessory veins

Occlude the main vein a few centimeters above the anastomosis and feel the anastomosis. Normally the thrill disappears and only a pulse remains. If the thrill persists, an accessory vein drains between the anastomosis and your finger [1,3]. Move the occlusion point up to locate it. A large accessory vein can steal the flow the main vein needs to mature [4].

5. The hand

Compare both hands: color, temperature, capillary refill, radial pulse, sensation and strength. Steal ischemia causes a cold, pale or cyanotic hand, pain that worsens during dialysis, tingling or weakness and, in advanced cases, ulcers or necrosis of the fingers [6]. A useful clue: if the hand's color or pulse improves when you compress the fistula, steal is likely. Pain at rest, loss of sensation or strength and finger lesions need urgent assessment.

Typical patterns

The causes and management of each problem are in the guides to stenosis, maturation and aneurysm.

When to act

• Immediately:
  • no thrill and no bruit;
  • bleeding from an aneurysm, or very thin, shiny or ulcerated skin over it;
  • a cold, painful hand at rest, or loss of sensation or strength;
  • signs of infection with fever.
• Promptly, to the vascular access team:
  • changes in the thrill or bruit;
  • the vein no longer collapses on arm elevation;
  • the pulse barely augments on occlusion;
  • arm swelling;
  • a new fistula that is not progressing at 4–6 weeks [4].

What matters most is change from that patient's usual pattern. Record the thrill, the bruit, the response to arm elevation and any new finding at every session.

Educational content. It does not replace supervised hands-on training or your unit's protocols.

References

1. Ibeas J, Roca-Tey R, Vallespín J, Moreno T, et al. Spanish Clinical Guidelines on Vascular Access for Haemodialysis (GEMAV). Nefrología. 2017;37(Suppl 1):1-191. doi.org
2. Vascular Access Society of Britain and Ireland (VASBI) and British Renal Society Vascular Access Special Interest Group. Clinical Practice Recommendations for Needling of Arteriovenous Fistulae and Grafts for Haemodialysis. 2018. thinkkidneys.nhs.uk
3. Salman L, Beathard G. Interventional nephrology: physical examination as a tool for surveillance for the hemodialysis arteriovenous access. Clin J Am Soc Nephrol. 2013;8(7):1220-1227. pubmed.ncbi.nlm.nih.gov
4. Beathard GA. An algorithm for the physical examination of early fistula failure. Semin Dial. 2005;18(4):331-335. doi.org
5. Asif A, Leon C, Orozco-Vargas LC, et al. Accuracy of physical examination in the detection of arteriovenous fistula stenosis. Clin J Am Soc Nephrol. 2007;2(6):1191-1194. pubmed.ncbi.nlm.nih.gov
6. Schmidli J, Widmer MK, Basile C, de Donato G, Gallieni M, et al. Vascular Access: 2018 Clinical Practice Guidelines of the European Society for Vascular Surgery (ESVS). Eur J Vasc Endovasc Surg. 2018;55(6):757-818. doi.org
7. Lok CE, Huber TS, Lee T, Shenoy S, et al. KDOQI Clinical Practice Guideline for Vascular Access: 2019 Update. Am J Kidney Dis. 2020;75(4 Suppl 2):S1-S164. doi.org