# 06 - 324 Interventional Nephrology

## 324 Interventional Nephrology

country by region, and it is influenced by economic and other major 
factors. In general, peritoneal dialysis is more commonly performed 
in poorer countries owing to its lower expense and the high cost of 
establishing in-center hemodialysis units.

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■FURTHER READING
Cooper BA et al: A randomized, controlled trial of early versus late 
initiation of dialysis. N Engl J Med 363:609, 2010.
Correa-Rotter R et al: Peritoneal dialysis, in Brenner and Rector’s 
The Kidney, 11th ed, MW Taal et al (eds). Philadelphia, Elsevier, 2020.
Fellstrom BC et al: Rosuvastatin and cardiovascular events in 
patients undergoing hemodialysis. N Engl J Med 360:1395, 2009.
Flythe JE et al: Rapid fluid removal during dialysis is associated with 
cardiovascular morbidity and mortality. Kidney Int 79:250, 2011.
Foley RN et al: Long interdialytic interval and mortality among 
patients receiving hemodialysis. N Engl J Med 365:1099, 2011.
Frequent Hemodialysis Network Trial Group: In-center hemodi­
alysis six times per week versus three times per week. N Engl J Med 
363:2287, 2010.
National Kidney Foundation: Kidney disease quality initiative 
clinical practice guidelines: Hemodialysis and peritoneal dialysis 
adequacy, 2006. Available at http://www.kidney.org/professionals/
kdoqi/guidelines.cfm.
Rocco MV et al: The effects of frequent nocturnal home hemodialysis: 
PART 9
Disorders of the Kidney and Urinary Tract
The frequent hemodialysis network nocturnal trial. Kidney Int 
80:1080, 2011.
U.S. Renal Data System: USRDS 2021 Annual Data Report: Atlas 
of End-Stage Renal Disease in the United States. Bethesda, National 
Institutes of Health, National Institute of Diabetes and Digestive and 
Kidney Disease, 2021.
Dirk M. Hentschel

Interventional 

Nephrology
Interventional nephrology is a procedure-oriented subspecialty with 
a focus on dialysis access for peritoneal and hemodialysis, typically 
performed under fluoroscopy. Ultrasound (US) evaluation of dialysis 
access is common, and some practitioners perform renal and renal 
artery US evaluation as well as renal biopsies. Endovascular creation 
of arteriovenous fistulas (AVFs) is a recent addition to the procedural 
spectrum; (open) surgical access creation by nephrologists is limited 
to very few centers in the United States, while common in China, 
Germany, India, and Italy.
Interventional nephrologists (INs) usually provide patient care in 
multidisciplinary teams that include clinical nephrologists; access sur­
geons with vascular, transplant, or general surgery background; other 
interventionalists (with radiology or cardiology training); and dialysis 
unit access coordinators, nurses, and technicians involved in needle 
placement. Long-term preservation of venous and arterial vascular 
access options is one tenet of chronic kidney disease (CKD) care, lead­
ing INs to advocate for specific vascular access options (tunneled smalldiameter catheters over peripherally inserted central catheters [PICCs]) 
and cardiac devices (epicardial rather than endovascular lead passage).
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■HISTORY
The history of vascular access for hemodialysis is closely tied to the 
history of dialysis. The first hemodialysis treatments in humans were 
performed in 1924 using glass needles to access the radial artery and 
return blood into the cubital vein. In 1943, a “rotating drum kidney” 
was used to dialyze a 29-year-old housemaid with CKD by surgical 

exposure of different arteries until she ran out of access sites after 12 
treatments. The challenge of repetitive vascular access prevented dialy­
sis from becoming a routine method for the treatment of CKD until the 
development of an arteriovenous Teflon shunt and then the develop­
ment of an autogenous arterial-venous access (arteriovenous fistula, 
AVF) by side-to-side-anastomoses between the radial artery and the 
cephalic vein at the wrist (Cimino fistula). Catheter-based approaches 
for chronic renal replacement therapy (RRT) were designed initially in 
1961 for hemodialysis and in 1968 for peritoneal dialysis, both using 
Dacron felt cuffs to protect against infection.
Material sciences have continued to evolve the development of grafts 
for use in hemodialysis. A modified bovine carotid artery biological 
graft was introduced in 1972, followed by the use of expanded polytet­
rafluoroethylene (ePTFE) grafts in 1976, and most recently in 2016, 
tissue-engineered blood vessels from human fibroblasts and endothe­
lial cells. Some ePTFE grafts are modified with a silicone layer to allow 
for early cannulation within days of insertion. Ultra-high-pressure (up 
to 40 atm) angioplasty balloons are a mainstay of peripheral and central 
venous therapy, and Nitinol self-expanding stents and stent grafts serve 
as rescue tools for unsuccessful angioplasty as well as vessel rupture 
with extravasation. The role of drug-coated balloons in dialysis access 
care continues to be assessed, although greater cost and, to date, mixed 
clinical trial results have limited widespread use.
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■PHYSIOLOGY AND PATHOPHYSIOLOGY 
OF DIALYSIS ACCESS
Peritoneal Dialysis 
Peritoneal dialysis (PD) catheters can be placed 
fluoroscopically, peritoneoscopically, laparoscopically, and open surgi­
cally. Procedural success is typically linked to provider experience and 
procedural planning to optimize positioning of the PD catheter coil as 
this improves function and decreases drain pain and other complica­
tions. The internal cuff is placed within the rectus sheath just laterally 
to the linea alba, while the external PD catheter cuff should be located 
2–4 cm from the skin exit site. Ingrowth of both cuffs ensures secure 
positioning of the catheter and allows water emersion. Over time, the 
peritoneal catheter can become encased in a fibrinous sheath, which, 
if limiting fluid flow during exchanges, can be disrupted by guidewire 
manipulation. Omental entrapment of the catheter often requires lapa­
roscopic intervention; omentopexy at the time of PD catheter placement 
can prevent later entrapment. Repeated infections affect the permeability 
of the peritoneal membrane, as does long-term exposure to glucose-con­
taining exchange solutions. Encapsulating peritoneal sclerosis is a latestage complication of PD thought to be triggered by repeated peritonitis.
Hemodialysis Catheters 
Dialysis catheters are typically made of 
polyurethane that softens at body temperature but is sufficiently strong 
to allow for blood flow rates of 400–500 mL/min in each of two chan­
nels inside a 14.5–16 French design without collapse of the catheter 
lumen. Tunneled catheters have a cuff that creates a barrier between 
skin flora at the exit site and the sterile catheter tunnel leading into the 
fibrinous sheath covering the catheter from the vessel insertion point 
to its tip. The fibrinous sheath can extend too far, impeding catheter 
flow and necessitating exchange of the catheter with disruption of 
the sheath by balloon angioplasty. Catheter-related bacteremia is best 
treated with exchange of the catheter and disruption of any fibrinous 
sheath, although removal of the catheter and delayed reinsertion after 
several days is also successful. Catheter infection-related sepsis unre­
sponsive to antibiotics requires removal of the catheter. Thrombotic 
occlusion and later sclerotic scarring of the vein at catheter insertion 
sites is common, however, and removal of a catheter may lead to loss 
of this access site. Catheter vessel wall contact points are thought to 
lead to central vein stenosis, which is more commonly observed in 
patients with catheter contact times of longer duration (>3 months). 
Catheter tip position in the large central veins instead of the right 
atrium causes additional injury from dynamic blood movement during 
dialysis treatments and should be corrected. A thrombus is commonly 
found attached to the catheter, often tethering the catheter to the vessel 
wall and right atrium. While some thrombi are mobile and dissolve 
with anticoagulation, a wall-tethered thrombus is often well organized

with cellular components and quite resistant to pharmacologic lysis. 
Clinically significant pulmonary embolism from catheter-associated 
thrombus is rare, and it may be that only intra-atrial thrombus >2 cm 
in diameter deserves active intervention.
Arteriovenous Graft and Fistulas 
During the first decades of 
hemodialysis for loss of renal function, U.S. patients were relatively 
young and without long-term systemic vascular disease. Creation of 
forearm Cimino AVFs was common, and access failure usually led to 
creation of a second AVF slightly higher up on the arm. As diabetes 
and hypertension with associated systemic arterial and venous vascular 
disease became more prevalent in the CKD population, placement of 
nonautogenous accesses (arteriovenous grafts [AVGs]) increased. In 
the mid-1990s, 65% of prevalent dialysis patients used an AVG for 
access. The United States was an international outlier in this regard, 
and studies associated increased mortality in U.S. dialysis patients with 
lower AVF prevalence. In the context of “Fistula First” and then 
“Fistula First, Catheter Last” campaigns, AVG prevalence decreased 
to its current value of <20%, while AVFs increased to near 65% preva­
lence. However, most centers still struggle with the challenging condi­
tions of arteries and veins in these patients requiring that 75% of AVFs 
are now created in the upper arm, where the veins a priori are larger in 
diameter, and arteries can deliver higher blood flow rates due to large 
vessel diameter (see Fig. 324-1).
To provide successful dialysis, an AVF or AVG has to provide at 
least the desired blood pump speed (Chap. 323) plus 100–200 mL/min 
to minimize recirculation and prevent collapse of the access. In the 
United States, this usually means flow in the 600–800 mL/min range. A 
fistula created using an artery with ≥2 mm diameter and a vein ≥3 mm 
will typically have flow volumes >500 mL/min when the systolic blood 
pressure is >100 mmHg. After creation of the arterial-venous anasto­
mosis (or insertion of the AVG), blood flow increases significantly: 
brachial artery flow at rest is typically <50 mL/min, but after access 
creation, flow volume in AVFs increases within weeks to 800 mL/min, 
while flow volume in AVGs increases within minutes to 1000 mL/min. 
The increased flow changes the arterial shear stress profile and leads to 
enlargement of the artery over time. In AVGs, this process is limited by 
the graft itself, which typically is 6 mm in diameter and 35–40 cm long, 
and access flows remain in the 1200–1800 mL/min range. The access 
vein in AVFs in the right shear stress environment enlarges over time, 
often to >10 mm in diameter in the upper arm such that the artery 
A
C
B
D
FIGURE 324-1  Dialysis access health depends on intra-access pressures and needle insertions. A. A right upper arm brachial-cephalic arteriovenous fistula (AVF) with 
two recurrences of clinically relevant inflow stenosis in 4 years has low-normal intra-access pressure before and after angioplasty; there is only minimal needle insertion 
site enlargement. B. In contrast, a right upper arm brachial-cephalic AVF with seven recurrences of cephalic arch outflow stenosis in 4-year cycles between states of highnormal to high intra-access pressures with notable needle insertion site enlargement. C. Focal needle insertions despite available graft segments led to penetrating skin 
ulcers over 3 years. D. Segmental needle rotation preserves skin integrity even after 7 years of arteriovenous graft (AVG) use.

continues to enlarge until a narrow segment in the venous conduit 
becomes flow limiting. Flow volumes in these mature upper arm AVFs 
are usually 1400–1800 mL/min, but after a few years can be as high as 
2000–4000 mL/min. Forearm AVFs usually have lower flow volumes 
(500–700 mL/min) as the feeding radial artery is of smaller diameter 
and, in the context of systemic vascular disease in the United States, 
only increases in diameter over many years.

Increased flows and pressure in the venous segment of the access 
circuit combine to lead to “chronic dialysis access disease” that mani­
fests differently for each type of the common long-term accesses in 
predetermined segments particularly prone to shear stress and needle 
insertion–related injury. AVGs develop venous anastomotic stenoses 
that recur with very short periodicity in the 3- to 4-month range. Stent 
grafts can effectively be deployed to extend patency for usually 1 year 
at the site, after which the buildup of pauci-cellular fibrous depositions 
at the stent edges requires re-angioplasty one to three times per year. 
Forearm radial-cephalic autogenous accesses of the Cimino type at the 
wrist are most prone to low flow due to juxta-anastomotic stenoses. 
Over time, these stenoses can stabilize, and with enlargement of the 
inflow artery, they effectively provide protection against excessive flows 
and their sequelae. “Snuff box” radial-cephalic fistulas require mini­
mal mobilization of the cephalic vein with fewer juxta-anastomotic 
stenoses. However, the additional side branches and associated venous 
valves may present as stenosis and require ligation to allow cannulation 
(see below discussion of augmentation). Upper arm brachial-cephalic 
autogenous accesses typically develop stenoses in the cephalic arch, 
which recur in accelerated fashion after each angioplasty. Flexible stent 
grafts in the cephalic arch extend intraprocedural intervals usually 
to 9–12 months. Upper arm transposed brachial-basilic autogenous 
accesses develop stenoses in the swing point where the basilic vein is 
curved during a mobilization procedure to provide a location more 
lateral and closer to the skin to facilitate needle cannulation. Angio­
plasty and stent graft placement approaches extend patency. In both 
types of upper arm accesses, there are often prolonged periods with 
increased intra-access pressures due to outflow stenoses, which lead 
to enlargement of needle insertion site aneurysm as the skin heals in 
a pressurized, stretched state. Continued use of pressurized accesses 
leads to enlargement of needle sites, then thinning of the skin, scab 
formation, and, finally, full-thickness ulceration with often significant 
bleeding events. Recognizing the occurrence of outflow stenoses early 
CHAPTER 324
Interventional Nephrology

is an important skill for nurses and technologists working in dialysis 
units to acquire in order to avoid irreversible loss of skin coverage and 
possible loss of the access.

High-access flow (>1500 mL/min) can lead to systemic complica­
tions, such as heart failure and pulmonary hypertension. Fistula inflow 
higher than outflow capacity leads to accelerated aneurysm formation 
and breakdown of skin coverage as intra-access pressures are increased 
over the ideal pressure of 20–35 mmHg. High-access flows are also 
associated with steal syndrome, typically ischemia of the hand. A 
variety of procedures have been described to reduce access flows, the 
most common being “banding,” where typically a 2-0 Prolene suture is 
guided around the inflow and a 3- or 4-mm spacer and is tied snugly 
over the spacer to create an inflow stenosis.
APPROACH TO THE PATIENT
Physical Examination of Dialysis Access
The 2019 Kidney Disease Outcomes Quality Initiative (KDOQI) 
vascular access guidelines were developed under the tenet, “[t]he 
right access for the right patient at the right time.” Progression of 
CKD is highly variable, many patients die from other causes before 
reaching end-stage renal disease (ESRD), and some AVFs require 
6–12 months to mature to usability in patients with hypertension 
and diabetes, leading to uncertainty as to when to create AVFs. 
The more common need of upper arm accesses for interventions to 
maintain patency favors the creation of forearm accesses during the 
pre-ESRD period. The processes of care from vein mapping, sur­
gery, follow-up visits after access creation, to availability and tim­
ing of open surgical or endovascular interventions have profound 
effects on the overall success rate needed to achieve mature and 
usable accesses and appear to be key factor in the highly variable 
outcomes across the United States.
PART 9
Disorders of the Kidney and Urinary Tract
A central skill in dialysis access evaluation is the physical exami­
nation. Five steps in the access examination capture all aspects of 
possible pathology: Pulsatility reflects the force of access expan­
sion during systole and the degree of softening during diastole. 
Very high blood pressures will suggest increased pulsatility, but the 
access softens remarkably during diastole. An outflow stenosis will 
lead to increased pulsatility and reduced softening during diastole. 
An inflow stenosis will blunt the systolic component and create the 
impression of an “empty” access during diastole unless there is a 
coexisting outflow stenosis. The audible flow murmur can be char­
acterized by pitch and continuity (Video 324-1). A change in pitch 
toward higher frequency is typical at the site of a stenosis due to 
accelerated flow velocity at this site. A discontinuous flow murmur 
indicates that during diastole flow is so low that no audible shear 
force is created; this is the sign of a severe inflow or outflow steno­
sis. Typically, the stenotic inflow murmur is faint (like a whistle), 
whereas the stenotic outflow murmur can be coarse and loud (akin 
to a handsaw) (Video 324-2). A thrill is palpable through the skin 
when the vessel is close enough to the surface and the flow high 
enough in relation to the diameter of the vessel to create vibration of 
the vessel wall. A continuous thrill can be a sign of a well-developed 
access, usually in the inflow segment, dissipating as the access ves­
sel branches and takes a deeper course. In contrast, a discontinuous 
thrill is found with severe stenosis. An isolated thrill is also found 
focally immediately after a stenosis. The differentiation from a 
“healthy” thrill can be made by documenting a change in pulsatil­
ity at the site of the focal thrill, increased retrograde (inflow) and 
decreased antegrade (outflow). Augmentation is the engorgement of 
the body of the access (where needles are inserted) with occlusion 
of the outflow necessary for safe and successful needle insertions. 
An inflow stenosis will impair augmentation, as will side branches 
and collaterals between the occluding finger/tourniquet and the 
inflow. The location of side branches can be elucidated by moving 
the occluding finger closer toward the anastomosis until augmenta­
tion is achieved. With several collaterals, this may be a staged phe­
nomenon. Collapse of the access with arm elevation (against gravity) 

is a measure of inflow and outflow capacity match or mismatch. 
A forearm access typically displays complete collapse, while upper 
arm accesses typically show only partial collapse. An outflow steno­
sis or very high inflow will decrease the degree of collapse; banding 
of an upper arm access or a natural flow-limiting stenosis may lead 
to complete collapse of an upper arm access.
Enlarged needle insertion sites (and any sites of suspected skin 
thinning) are best examined while occluding inflow: the completely 
empty access allows palpation of a firm, layered thrombus inside 
aneurysms as well as a better appreciation of the thickness of the 
overlying skin by rolling it between thumb and index finger. The 
chest wall and neck should be inspected for the presence of skin 
veins and venous distention, which are associated with central 
venous stenosis or occlusion, as is ipsilateral arm edema. 
PRESERVATION OF VENOUS “REAL ESTATE”
Preserving access is a key care component for the patient with 
advancing CKD. Approximately 8–10% of this population has the 
need for cardiac rhythm management devices (CRMDs) that can 
lead to loss of the upper arm cephalic vein as well as central venous 
stenoses and occlusions around device leads. Planning for which 
side a future autogenous access is to be placed and where a CRMD 
is located is recommended in all cases. CKD patients also have an 
increased frequency of hospitalizations, some of which require 
intravenous access beyond the hospital stay for antibiotics, nutri­
tional support, or hydration. Avoiding PICCs in a patient with CKD 
stage 3 or 3b and higher and, instead, using internal (or external) 
jugular vein tunneled small-diameter catheters preserves arm veins 
for long-term access creation. Arterial access points for cardiac pro­
cedures should be chosen with AVF creation in mind.
Approach to the dialysis access of patients with a kidney trans­
plant depends on the function of the transplanted kidney, the risk 
of recurrence of kidney disease in the transplant, the ability to limit 
access flow over time while maintaining patency, and the potential 
benefit of the AVF for blood pressure control.
■
■FURTHER READING
DePietro DM, Trerotola SO: Choosing the right treatment for the 
right lesion, Part II: A narrative review of drug-coated balloon angio­
plasty and its evolving role in dialysis access maintenance. Cardiovasc 
Diagn Ther 13:233, 2023.
Haskal ZJ, Dolmatch BL: Hemodialysis access stent graft trials: Past, 
present, and future. Cardiovasc Intervent Radiol 46:1154, 2023.
Hentschel DM: Hemodialysis access maintenance and salvage, in 
Mastery of Surgery: Vascular Surgery: Hybrid, Venous, Dialysis Access, 
Thoracic Outlet, and Lower Extremity Procedures, Philadelphia, 
Wolters Kluwer, 2015, pp 191–205.
Hentschel DM et al: Hemodialysis access interventions, in Vascular 
Imaging and Intervention, 2nd ed. D Kim et al (eds). India, Jaypee 
Brothers Medical Publishers, 2020, pp 1655–1686.
Hoggard J et al: Guidelines for venous access in patients with chronic 
kidney disease. Semin Dial 21:186, 2008.
Lok CK et al: KDOQI clinical practice guideline for vascular access: 
2019 update. Am J Kidney Dis 75:S1, 2020.
Ozaki CK et al: Non-maturing autogenous arteriovenous fistula, in 
Vascular Decision Making. Philadelphia, Wolters Kluwer, 2020.
VIDEO 324-1  Flow murmur of an upper arm brachial-cephalic autogenous access 
(arteriovenous fistula [AVF]) with a juxta-anastomotic stenosis. The sound is 
discontinuous as the stenosis is severe enough that only during systole is the flow 
volume high enough to create audible turbulence. There also is a high-pitch component 
of the murmur due to the high flow velocity during the peak of the flow cycle.
VIDEO 324-2  Flow murmur of an upper arm brachial-cephalic autogenous access 
(arteriovenous fistula [AVF]) with a juxta-anastomotic stenosis after angioplasty. 
The sound is now continuous with systolic-diastolic modulation. There is an even 
pitch, overall lower than the pitch associated with peak flow in the setting of an 
untreated stenosis.