Viva · IR system
Dialysis Access Viva Questions
Oral-exam style questions and answers on dialysis access for MD, DNB and super-specialty practical examinations. Each answer links back to the playbook or Library entry it was written from.
- When should a dialysis-access stenosis be treated?
- Treat when a clinical or dialysis indicator of access dysfunction is present and imaging confirms a culprit stenosis of at least 50%. Angiographic stenosis without clinical dysfunction is not, by itself, an indication for pre-emptive angioplasty.
- What must a complete fistulogram show?
- It should evaluate the feeding artery, arterial anastomosis, juxta-anastomotic segment, entire cannulation or graft segment, peripheral venous outflow, cephalic arch when relevant and central veins to the right atrium.
- How do you assess arterial inflow from a venous access?
- Use brief controlled venous-outflow compression to reflux contrast across the anastomosis, or place a catheter close to the anastomosis if reflux is inadequate. Avoid forceful prolonged compression and confirm distal hand perfusion.
- How do you size the angioplasty balloon?
- Size approximately 1:1 to an adjacent normal reference vessel, not to the stenotic lumen. Oversizing increases rupture risk and undersizing causes residual stenosis and recoil.
- What defines technical success after fistuloplasty?
- The usual anatomical endpoint is 30% or less residual stenosis with brisk flow and no significant recoil, extravasation or flow-limiting dissection. Clinical success is improvement of dialysis access function.
- How do you manage a resistant balloon waist?
- Confirm position and sizing, then consider prolonged inflation, a purpose-built high- or ultrahigh-pressure balloon, or a scoring/cutting balloon. Escalation must remain within device limits and stop when rupture risk outweighs benefit.
- Why is cephalic-arch stenosis difficult and how is it treated?
- The arch is curved, constrained by fascia and exposed to high-flow turbulence, producing resistant stenosis, recoil and frequent restenosis. Start with high-pressure PTA; consider a covered stent for rupture, significant recoil or selected recurrence, and surgical transposition when recurrence is frequent.
- What is the role of drug-coated balloons?
- A DCB is used only after successful vessel preparation and may improve target-lesion patency in selected native AVF lesions, but trials have been heterogeneous. Current guidance does not support routine DCB use for every access stenosis.
- What is the preferred vein for a tunneled dialysis catheter?
- The **right internal jugular vein** is preferred because it provides a relatively straight course to the right atrium and generally offers better function and patency.
- Where should the dialysis catheter tip lie?
- The functional tip should lie in the **mid-right atrium**. A proximal tip encourages dysfunction and fibrin-sheath formation, whereas an excessively deep tip may cause arrhythmia or cardiac injury.
- What is the first treatment for catheter dysfunction?
- Exclude mechanical causes and use an intraluminal thrombolytic such as alteplase or urokinase. Mechanical exchange is considered when these measures fail.
- How is a fibrin sheath treated?
- A dysfunctional catheter is exchanged over guidewire with optional balloon disruption of the sheath, commonly using an approximately 10 mm balloon selected for the vein.
- Why is subclavian access avoided?
- It has a higher risk of central venous stenosis, which may compromise future ipsilateral fistula or graft creation and function.
Endovascular Evaluation and Treatment of Dialysis Access Stenosis
Endovascular Evaluation and Treatment of Dialysis Access Stenosis
Endovascular Evaluation and Treatment of Dialysis Access Stenosis
Endovascular Evaluation and Treatment of Dialysis Access Stenosis
Endovascular Evaluation and Treatment of Dialysis Access Stenosis
Endovascular Evaluation and Treatment of Dialysis Access Stenosis
Endovascular Evaluation and Treatment of Dialysis Access Stenosis
Endovascular Evaluation and Treatment of Dialysis Access Stenosis