Learning Objectives

By the end of this chapter, learners will be able to:
– Define interventional nephrology and its scope of practice.
– Compare types of hemodialysis vascular access and select appropriate access based on patient factors.
– Recognize and manage common access complications (thrombosis, stenosis, infection, aneurysm/pseudoaneurysm, steal).
– Outline the principles, indications, contraindications, and post-care of percutaneous kidney biopsy.
– Describe other key interventional procedures performed by nephrologists (e.g., PD catheter insertion, nephrostomy, cyst management).
– Apply practical strategies for surveillance, cannulation, and catheter care to optimize outcomes.

27.1 Introduction to Interventional Nephrology

Interventional nephrology is a procedural subspecialty focused on minimally invasive, image-guided diagnostics and treatments related to kidney disease and dialysis. Its core activities include:
– Establishing, maintaining, and salvaging hemodialysis vascular access.
– Performing percutaneous kidney biopsies (native and transplant).
– Inserting and troubleshooting peritoneal dialysis (PD) catheters.
– Managing urinary tract obstruction (e.g., nephrostomy, ureteral stents in collaboration with urology/interventional radiology).
– Selected endovascular interventions for renal and transplant vascular disease in appropriate settings.

This integrated approach enhances continuity of care, shortens time-to-intervention, and improves dialysis adequacy and patient outcomes.

27.2 Hemodialysis Vascular Access: Types and Selection

Reliable access is essential for hemodialysis. Selection depends on anticipated dialysis duration, vascular anatomy, comorbidities, and urgency.

Access types:
– Arteriovenous fistula (AVF): Autogenous artery-to-vein anastomosis (e.g., radiocephalic, brachiocephalic, brachiobasilic transposition). Typically matures over weeks to months.
– Advantages: Best long-term patency; lowest infection and thrombosis risk.
– Limitations: Requires maturation; risk of non-maturation; not feasible in all patients.

• Arteriovenous graft (AVG): Synthetic conduit (commonly expanded PTFE) between artery and vein; usable sooner than AVF.
• Advantages: Shorter time to cannulation; feasible with suboptimal veins; flexible placement sites.

• Limitations: Higher infection and thrombosis rates; shorter patency than AVF.

• Central venous catheter (CVC): Tunneled cuffed (longer-term) or non-tunneled (temporary), inserted into large central veins.

• Advantages: Immediate use; no maturation required.
• Limitations: Highest risks of infection, thrombosis, central venous stenosis; lower achievable blood flow.

Site considerations for CVCs:
– Right internal jugular vein is preferred to minimize stenosis and improve tip positioning (cavoatrial junction/right atrium).
– Avoid subclavian vein when feasible due to high central venous stenosis risk.
– Femoral site may be used for short-term access; infection and dysfunction risks are higher, especially in obesity or prolonged use.

A pragmatic principle: AVF is generally preferred when feasible; AVG is appropriate when AVF is unlikely to mature or as a secondary option; CVC is used when dialysis is urgent or other access is not immediately available.

27.3 Preoperative Planning and Access Creation

• Vascular mapping: Duplex ultrasound of arteries and veins (diameter, depth, flow, compressibility) guides selection and predicts maturation.
• Access choice strategy:
• Non-dominant upper limb preferred.
• Distal-to-proximal progression (e.g., snuffbox/radial–cephalic → brachiocephalic → brachiobasilic transposition).
• Consider diabetes, peripheral arterial disease, prior catheters (central venous stenosis risk), occupation, and life expectancy.
• Anesthesia: Local with sedation versus regional; ultrasound guidance is standard of care for cannulation and for needle placement during mapping and selected procedures.
• Maturation assessment: Physical exam (thrill/bruit), diameter and flow by duplex, usability for two-needle cannulation (e.g., flow typically ≥600 mL/min in upper arm, ≥500 mL/min in forearm; thresholds vary by program).

27.4 Cannulation, Surveillance, and Maintenance

• Cannulation techniques:
• Rope-ladder rotation is preferred to distribute punctures.
• Buttonhole technique may be used in mature AVFs with strict asepsis and consistent angle/depth; avoid in AVGs due to infection risk.
• Area puncture should be avoided.
• Ultrasound-guided cannulation is helpful for deep or difficult accesses.
• Infection prevention: Hand hygiene, skin antisepsis (e.g., chlorhexidine–alcohol where available), single-use needles, and aseptic technique.
• Surveillance and monitoring:
• Regular physical exam (“look, listen, feel”) to detect stenosis (high-pitched bruit, loss of thrill), aneurysm, edema, or hand ischemia.
• Access flow measurements, dynamic venous pressure, recirculation testing, and duplex ultrasound can assist detection of dysfunction. Programs vary in routine surveillance protocols; intervene when a correctable lesion correlates with clinical signs/symptoms or inadequate dialysis.
• Catheter locking solutions:
• Anticoagulant (e.g., citrate or heparin) and/or antimicrobial lock solutions per institutional protocols to reduce thrombosis and infection risk.

27.5 Complications of Vascular Access and Their Management

• Thrombosis:
• Causes: Underlying stenosis, hypotension, hypercoagulability, compression.

• Management: Prompt pharmacomechanical thrombolysis and thrombectomy; angioplasty of causative stenosis; surgical revision if endovascular salvage fails.

• Stenosis:

• Sites: Juxta-anastomotic segment, cephalic arch (AVF), graft–vein anastomosis (AVG), central veins (prior CVCs).

• Management: Percutaneous transluminal angioplasty (PTA) is first-line. Stent-grafts may be used for elastic recoil, recurrent stenosis, or select venous anastomotic lesions. Bare-metal stents are less favored due to in-stent restenosis.

• Infection:

• CVC: Exit-site/tunnel infection or catheter-related bloodstream infection (CRBSI). Management includes systemic antibiotics, catheter removal or exchange over a guidewire in stable, selected cases, and source control per local protocols.
• AVG: Infections often require graft excision (partial or complete) plus antibiotics.

• AVF: Cellulitis may respond to antibiotics; abscess or mycotic aneurysm requires surgical management.

• Aneurysm and pseudoaneurysm:

• Aneurysm: True dilation from repeated cannulation; fragile skin, rapid expansion, or pain suggests risk.
• Pseudoaneurysm: Contained rupture, often related to puncture or infection.

• Management: Urgent surgical evaluation for thinning skin, rapid growth, pain, ulceration, or bleeding; options include surgical repair, interposition grafting, or endovascular exclusion in select cases.

• Dialysis access–related steal syndrome (DASS):

• Features: Hand pain, coolness, numbness, decreased pulses; severe cases with rest pain, tissue loss, or neuropathy.
• Evaluation: Physical exam, pulse oximetry, Doppler ultrasound; consider digital pressures.

• Management: Flow reduction or revascularization procedures (e.g., DRIL—distal revascularization with interval ligation; RUDI—revision using distal inflow; banding; PAI—proximalization of arterial inflow). Tailor to severity and anatomy.

• High-output cardiac failure:

• Consider when access flow is excessively high with heart failure symptoms.

• Management: Flow reduction procedures after cardiology evaluation.

• Central venous stenosis:

• Risk increased by prior subclavian/ij catheters and ipsilateral devices.

• Management: PTA and, for recurrent or resistant lesions, stent-grafts. Prevent by avoiding subclavian catheterization when possible.

• Hematoma and infiltration:

• Prevention: Proper hemostasis, standardized cannulation technique.
• Management: Compression, rest, and re-evaluation; adjust needle size/technique.

27.6 Central Venous Catheters: Practical Considerations

• Types: Non-tunneled (short-term/ICU), tunneled cuffed (intermediate/longer-term).
• Site and tip position: Prefer right internal jugular; ultrasound-guided insertion; tip at cavoatrial junction/right atrium for optimal flow.
• Infection prevention bundles: Maximal sterile barriers, chlorhexidine skin prep (where available), sterile dressings, securement devices, and staff education.
• Catheter dysfunction:
• Causes: Thrombus, fibrin sheath, malposition, kinking.
• Management: Thrombolytic dwells (per protocol), catheter exchange over a guidewire, fibrin sheath disruption/stripping, repositioning. Evaluate for central venous stenosis if recurrent.

27.7 Percutaneous Kidney Biopsy

• Indications:
• Unexplained AKI or CKD; nephrotic-range proteinuria; persistent hematuria with proteinuria; suspected or monitored glomerular disease; evaluation of renal transplant dysfunction (e.g., rejection, drug toxicity, recurrent disease).
• Contraindications (assess locally and individually):
• Absolute: Uncorrectable bleeding diathesis, uncontrolled severe hypertension, active renal/perirenal infection, inability to cooperate/safely position.
• Relative: Solitary native kidney, pregnancy, morbid obesity, small echogenic kidneys, anatomic abnormalities, anticoagulation/antiplatelet therapy (timing of interruption depends on agent, renal function, and thrombosis risk).
• Pre-biopsy preparation:
• Review indications, consent, and imaging to localize kidneys.
• Optimize blood pressure and correct coagulopathy per institutional thresholds (e.g., INR, platelet count).
• Manage antithrombotics with multidisciplinary input; timing of holding/resumption depends on agent and thrombotic risk.
• Technique:
• Ultrasound-guided biopsy is standard; CT guidance may be used selectively.
• Native kidney: Typically prone; lower pole cortex targeted; spring-loaded needle.
• Transplant kidney: Usually supine; superficial anterior allograft.
• Number of passes balances diagnostic yield and bleeding risk.
• Complications:
• Most common: Bleeding (perinephric hematoma, macroscopic hematuria). Arteriovenous fistula can occur and often resolves spontaneously.
• Rare: Severe hemorrhage requiring transfusion or intervention, infection, adjacent organ injury.
• Post-biopsy care:
• Supine/prone rest for several hours; monitor vitals, hematuria, flank pain, and hemoglobin. Observation protocols vary (e.g., 4–24 hours) by local policy and patient risk. Provide clear return precautions for delayed bleeding.

27.8 Other Interventional Procedures

• Peritoneal dialysis (PD) catheter insertion:
• Techniques: Percutaneous Seldinger, laparoscopic, or surgical open; image guidance enhances placement accuracy.
• Urgent-start PD can be considered with modified exchanges and close monitoring.
• Troubleshooting: Malposition, leaks, omental wrap, peritonitis, exit-site/tunnel infections.
• Renal cyst aspiration and sclerotherapy:
• Indicated for symptomatic simple cysts causing pain/compression. Aspiration with sclerosing agent to reduce recurrence.
• Urinary tract obstruction:
• Percutaneous nephrostomy or coordination for ureteral stents in obstructive uropathy causing AKI, infection risk, or pain.
• Renal artery/inter-renal interventions:
• Endovascular angioplasty/stenting may be considered in select patients (e.g., hemodynamically significant stenosis with recurrent flash pulmonary edema, refractory hypertension, or deteriorating kidney function in appropriate clinical context). Decisions should be individualized, often in multidisciplinary consultation.

27.9 Peri-procedural Safety: Sedation, Antimicrobials, and Radiation

• Sedation and analgesia:
• Use minimal effective sedation; continuous monitoring of airway, breathing, circulation. Consider local anesthesia with or without moderate sedation depending on procedure and patient factors.
• Antimicrobial prophylaxis:
• Not routinely indicated for clean percutaneous procedures (e.g., kidney biopsy) unless specific infection risks exist per local policy.
• Manage suspected or confirmed infections promptly with source control and antimicrobials.
• Radiation safety:
• Use ultrasound when feasible to minimize ionizing radiation.
• For fluoroscopic procedures, adhere to ALARA principles and document exposure.

SUMMARY

Key Points on Interventional Nephrology
– Scope: Image-guided, minimally invasive procedures central to dialysis access, kidney biopsy, and selected urologic/vascular interventions.
– Vascular access:
– AVF generally offers the best patency and lowest infection risk when feasible.
– AVG enables earlier use but has higher infection and thrombosis rates than AVF.
– CVC provides immediate access but carries the highest risks and should be minimized in duration.
– Complications and management:
– Thrombosis: Endovascular salvage with thrombolysis/thrombectomy and correction of stenosis.
– Stenosis: PTA first-line; stent-graft for select recurrent/elastic lesions.
– Infection: Antibiotics plus device removal/excision as indicated.
– Aneurysm/pseudoaneurysm and steal: Early recognition and tailored surgical/endovascular solutions.
– Kidney biopsy:
– Essential diagnostic tool; ultrasound guidance is standard; bleeding is the principal risk.
– Careful patient selection, optimization, and post-procedure monitoring reduce complications.
– Other procedures:
– PD catheter insertion and troubleshooting; cyst sclerotherapy; nephrostomy/stenting for obstruction; selected renal vascular interventions.

Quick Guide
– Prefer AVF when feasible; plan early with duplex mapping.
– Examine the access at every dialysis session; intervene when dysfunction correlates with a correctable lesion.
– Avoid subclavian CVCs if possible; use right IJ and ultrasound guidance.
– After biopsy, monitor closely for bleeding; give clear return precautions.

CLINICAL PEARLS

Diagnostic Pearls
– Regular physical exam of AVF/AVG (thrill, bruit, pulse augmentation) is highly predictive for stenosis or thrombosis.
– In suspected DASS, compare bilateral hand perfusion and use Doppler to assess digital pressures and flow reversal.
– Duplex ultrasound before access creation improves selection and maturation rates.

Management Pearls
– Early referral for declining dialysis adequacy, elevated venous pressures, or cannulation difficulty can salvage access before thrombosis.
– For CVC dysfunction, trial thrombolytic lock before catheter exchange; evaluate for fibrin sheath if recurrent.
– Treat AVG infections aggressively; many require surgical excision in addition to antibiotics.

Procedural Pearls
– Use real-time ultrasound guidance for kidney biopsy and for difficult cannulation to reduce complications.
– Coordinate anticoagulation/antiplatelet management with the prescribing team; balance thrombosis and bleeding risks.
– Buttonhole cannulation is for mature AVFs with meticulous asepsis; avoid in grafts due to infection risk.

Safety Pearls
– Control blood pressure prior to biopsy and maintain post-procedure surveillance per protocol.
– Prefer right internal jugular for tunneled CVCs; confirm tip at the cavoatrial junction/right atrium.
– Consider access flow reduction if symptomatic high-output heart failure is suspected.

VISUAL MATERIALS

Proposed figures and tables (to be created):
– Diagram: Hemodialysis vascular access types (AVF, AVG, CVC) with common anatomical sites.
– Flowchart: Access selection and planning (duplex mapping → access choice → maturation criteria).
– Table: Comparison of AVF vs AVG vs CVC (time to use, infection/thrombosis risk, patency, pros/cons).
– Diagram: Common stenosis sites (juxta-anastomotic, cephalic arch, graft–vein, central veins).
– Algorithm: Management of access thrombosis and stenosis (endovascular vs surgical pathways).
– Schematic: Steal syndrome assessment and treatment options (DRIL, RUDI, banding, PAI).
– Stepwise illustration: Ultrasound-guided native and transplant kidney biopsy.
– Table: Biopsy pre-procedure considerations (indications, relative/absolute contraindications, monitoring).

MULTIPLE CHOICE QUESTIONS

1) Which vascular access is generally preferred for long-term hemodialysis when feasible?
– A. Tunneled right femoral CVC
– B. Arteriovenous fistula (AVF)
– C. Arteriovenous graft (AVG)
– D. Non-tunneled internal jugular CVC
Answer: B
Explanation: AVFs typically provide superior patency and the lowest infection/thrombosis rates compared with AVGs and CVCs.

2) The most common underlying cause of hemodialysis access thrombosis is:
– A. Hyperkalemia
– B. Underlying stenosis
– C. Excessive heparin during dialysis
– D. Allergy to graft material
Answer: B
Explanation: Stenosis leads to disturbed flow and predisposes to thrombosis; addressing the lesion is key to durable salvage.

3) In a patient requiring urgent hemodialysis with no existing access, the preferred catheter site is:
– A. Left subclavian vein
– B. Right internal jugular vein
– C. Left external jugular vein
– D. Right femoral vein for long-term use
Answer: B
Explanation: The right IJ provides the most direct route to the right atrium and has lower central stenosis risk; subclavian access should be avoided when possible.

4) The first-line endovascular treatment for a significant venous anastomotic stenosis in an AVG is:
– A. Bare-metal stent placement
– B. Balloon angioplasty (PTA)
– C. Surgical ligation of the graft
– D. Systemic thrombolysis
Answer: B
Explanation: PTA is first-line; stent-grafts are considered for recurrent or resistant lesions.

5) A patient with a mature AVF develops hand pain, coolness, and numbness distal to the anastomosis. The most likely diagnosis is:
– A. Catheter-related bloodstream infection
– B. Steal syndrome (DASS)
– C. Graft pseudoaneurysm
– D. Hyperkalemia-induced neuropathy
Answer: B
Explanation: Symptoms suggest ischemia distal to the access, characteristic of DASS.

6) Which statement about percutaneous native kidney biopsy is most appropriate?
– A. CT guidance is mandatory for safety
– B. Uncontrolled severe hypertension is a contraindication until optimized
– C. Antimicrobial prophylaxis is routinely required
– D. Post-biopsy observation is unnecessary if the patient feels well
Answer: B
Explanation: Blood pressure should be controlled and coagulopathy corrected prior to biopsy; ultrasound guidance is standard, and routine antibiotics are not generally indicated.

7) For an infected AVG with systemic signs and purulent drainage, the most appropriate management is:
– A. Oral antibiotics alone for 14 days
– B. Exchange the graft over a guidewire
– C. Surgical excision (partial or complete) plus antibiotics
– D. Heparin lock solution
Answer: C
Explanation: Graft infections often require surgical removal with targeted antibiotics to achieve source control.

8) A tunneled CVC has progressively lower blood flows and high venous pressures despite optimal dialysis settings. After a thrombolytic lock fails, the next best step is:
– A. Increase blood flow rate to overcome resistance
– B. Exchange the catheter over a guidewire and evaluate for fibrin sheath
– C. Switch to peritoneal dialysis immediately
– D. Begin long-term warfarin therapy
Answer: B
Explanation: Refractory dysfunction is often due to fibrin sheath or malposition; exchange with possible sheath disruption is appropriate.

9) Which cannulation practice is recommended to reduce aneurysm formation in AVFs?
– A. Repeated puncture at the same site (area puncture)
– B. Buttonhole technique in synthetic grafts
– C. Rope-ladder rotation of needle sites
– D. Use of larger needles as early as possible
Answer: C
Explanation: Rope-ladder rotation distributes puncture sites and lowers aneurysm risk; buttonhole is not recommended for grafts.

10) A patient with presumed renovascular hypertension and unilateral renal artery stenosis is referred for stenting. Which statement is most appropriate?
– A. All unilateral stenoses benefit from stenting
– B. Endovascular therapy is reserved for select high-risk presentations after multidisciplinary assessment
– C. Surgery is preferred over angioplasty in all cases
– D. Medical therapy is contraindicated
Answer: B
Explanation: Revascularization may be considered for select scenarios (e.g., recurrent flash pulmonary edema, refractory hypertension with hemodynamically significant stenosis), with individualized decision-making.

POWERPOINT PRESENTATION

Slide 1: Title – Interventional Nephrology: Practical Essentials
– Scope of practice and why it matters
– Procedural integration in kidney care

Slide 2: Hemodialysis Access Options
– AVF, AVG, CVC overview
– When to choose each

Slide 3: Preoperative Planning
– Duplex mapping and access selection
– Distal-to-proximal, non-dominant arm strategy

Slide 4: Cannulation and Maintenance
– Rope-ladder vs buttonhole (AVF only)
– Ultrasound-guided cannulation
– Infection prevention measures

Slide 5: Managing Stenosis and Thrombosis
– PTA first-line; role of stent-grafts
– Thrombolysis/thrombectomy for clot

Slide 6: Infections and Aneurysms
– CVC/AVG infections: diagnosis and management
– Aneurysm/pseudoaneurysm indications for repair

Slide 7: Steal Syndrome and High-Flow Access
– Recognition and workup
– DRIL, RUDI, banding, PAI; flow reduction

Slide 8: Central Venous Catheters
– Site selection and tip position
– Dysfunction management and prevention bundles

Slide 9: Kidney Biopsy Essentials
– Indications/contraindications
– Technique and post-care
– Complications and mitigation

Slide 10: PD Catheters and Other Procedures
– Insertion options and urgent-start PD
– Cyst sclerotherapy, obstruction management

Slide 11: Safety Considerations
– Sedation and monitoring
– Antimicrobials and radiation safety

Slide 12: Clinical Pearls and Take-Home Points
– Examine every access
– Plan early; intervene early
– Balance bleeding and thrombosis risks

Educational Disclaimer: This chapter is for educational purposes for postgraduate clinicians. It does not replace clinical judgment or local institutional guidelines. Management decisions should be individualized and aligned with current policies and specialist consultation when appropriate.

Visual learning: Interventional Nephrology

Presentation resource: The Kidney Hub clinical-series PowerPoint for Chapters 22–30 accompanies these chapters for teaching use.