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36 Creating aPercutaneous Arteriovenous Fistula: Evidence andTechniques
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Early Results
Early results for the WavelinQ system have been reported
both for the original 6 Fr and newer 4 Fr devices. These pivotal studies were performed with non-US patient populations. The Novel Endovascular Access Trial (NEAT)
performed in Canada, Australia and New Zealand using the
6 Fr device reported a 98% technical success rate and 8%
serious adverse event rate [18]. In terms of physiologic and
clinically important outcomes, the investigators found 87%
were physiologically suited for dialysis based on ultrasoundmeasured venous diameters and computed ow rates. Among
those patients on HD, they reported a 64% functional usability. Twelve-month primary and cumulative patency were
69% and 84%, respectively [18]. A real-world application
study looked at short term (mean follow-up 73days) outcomes in a single center using WavelinQ [19]. In their
32-patient series, the authors reported 100% technical success, procedure lengths averaging 120min and a 25% periprocedural complication rate. Over their relatively short
follow-up, they found that 42% of patients required further
endovascular intervention to assist with maturation while
13% required surgical intervention. At the conclusion of
their follow-up, mean ows were 1.1L at the brachial artery
and 447mL at the cephalic. Despite this, only 48% of the
patients receiving HD were using their pAVF at study termination [19].
Initial experiences with the 4 Fr WavelinQ devices have
also been described. Two such studies, the EASE trials
(EASE, 32 patients, NCT 03708770; EASE-2, 24 patients,
NCT 03708562) were completed in Paraguay while the EU
postmarket clinical follow-up study was performed in
Germany (EU study, 64 patients, NCT 02682420) [13].
Aggregated results across these three studies demonstrated a
procedural success rate of 97%, primary patency of 72%,
primary-assisted patency of 81%, and secondary 6-month
patency of 88% (KM extrapolation) [13]. The group reported
2.5% rate of serious adverse events and 6% procedurally
related adverse events. Reinterventions were required in
19% of patients split relatively closely between maturation
and maintenance procedures. Concomitant brachial vein
embolization was required in 67% of patients. Among the 99
patients on HD at enrolment, 64% had successful cannulation at 3months and 78% at 6months. Functional cannulation (dened as successful cannulation and use for 2/3 of
dialysis sessions over a 28-day period) occurred in 43% by
3months and 53% by 6months. The mean time to achievement of functional cannulation was 140days [13].
Early results for the Ellispys device from the Pivotal
Multicenter trial describe 95% technical success and no
Table 36.3 Short-term follow-up outcomes
Ellipsys WavelinQ
Technical success 95–100% 97–100%
Procedural duration (min) 14–15 63–120
Cannulation rate (4weeks) 68% 54%
Cannulation rate (6months) 80% 79%
Time to cannulation (day) 60–100 49–140
Functional cannulation rate 88% 53%
Physiologic readiness by imaging 86% 87%
Failure rate 15% 37%
Need for additional interventions 28% 19–27%
6months primary patency 32% 33–72%
12months primary patency 54, 87% 69%
6months primary assisted patency – 81%
12months primary assisted patency 85% –
6months secondary patency 82% 60, 70, 88%
12months secondary patency 96% –
Interventions per patient-year 0.96 0.46
Procedure-related adverse events 0, 2.5% 6, 8.6, 25%
device related adverse events [17]. They reported cumulative
patency of 92%, 89%, and 87% at 90, 180, and 360days.
Functional patency was achieved in 98%, 98%, and 92% at
90, 180, and 360days. Two-needle cannulation was achieved
in 88% of the patients on dialysis at study initiation. This was
achieved at a mean of 100days. Though technique has since
changed, at the time of the pivotal trial, it was not routine
practice to dilate the anastomosis with a 5mm×2cm compliant balloon as it is currently. Thus, the pivotal study
entailed 72% maturation procedure requirement. In addition
to this angioplasty, 31% underwent cubital vein ligation,
32% brachial vein embolization and 26% surgical transposition. Of the 107 patients in the trial, 36 (34%) required 66
procedures to maintain functionality; see Table36.3.
Later Results
Results for mid-term and later have been published for
Ellipsys. This is inclusive of a procedural change to include
compliant balloon angioplasty (5mm×2cm) at the index
procedure and traversal of the perforating vein with the
access needle rather than a wire (which can induce spasm).
Mallios et al. published their single center results on 234
patients with a mean follow-up of 302days [2]. This group
had a 99% technical success rate and an average procedural
duration of 15min. Primary, primary assisted and secondary
patency at 1year were: 54%, 85%, and 96%. The most frequent secondary intervention comprised angioplasty of the
anastomosis and draining perforator via distal radial arterial
access (Figs. 36.4 and 36.5). Ten percent of patients did
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K. M. Bennett and A. Mallios
Fig. 36.4 Algorithm for maintenance and assisted maturation for percutaneous stula created with Ellipsys—reproduced with permission from
Mallios etal. J Vasc Surg [16]
require supercialization due to cannulation issues—split
between basilic vein transposition and surgical lipectomy for
deeper cephalic veins. Importantly, no patients developed
draining vein stenosis of the cephalic arch or central venous
outow [2].
Five-year results from the Pivotal multicenter Ellipsys
trial have also been reported by Hull etal. [20]. Eighty-ve
patients were available for long-term follow-, of which 84
had mature stulas and 78/79 dialysis-dependent patients
were using their pAVF with two needles at at least 2/3 sessions at the prescribed rate in a month. Over the 5years of
follow-up, maintenance interventions were required in 32%,
resulting in 0.32 procedures per patient-year in years 2–5.
Cumulative patency rates at 1 and 5years were 90% and
82%. Functional patency rate at study-end was 92% [20].
Comparing Costs
Addition to the eld of minimally invasive procedures
always entails an initial increase in price of the index procedure related to device research, development and production
costs. A notable example still expounded upon throughout
the literature is endovascular aneurysm repair (EVR). Some
initial analysis suggests that while pAVF has a clear early
increase in cost compared to sAVF related to device expense,
the lower rate of requirement for reintervention in the rst
year alone more than makes up for the initial nancial investment [21, 22].
Relative Need forReintervention
andRegional Variation
The comparative need for reintervention between Ellipsys
and WavelinQ is actually more challenging to assess using
the extant literature than might be expected. Published
results overall suggest a higher rate of interventions for
either maturation or supercialization in Ellipsys as opposed
to WavelinQ [13, 17–20]. As underscored by Illig etal.; however, the WavelinQ data for lower reintervention rates almost
entirely originates from studies performed outside of the
United States. In contrast, the studies suggesting higher rates
of intervention in the Ellipsys patients are heavily weighted
by studies in the United States (and, to some extent, Mexico)
[8]. While it is conrmed that most US patients require further intervention to achieve functionality, this differs from
the European data. Large series in Europe describe only 11%
of patients requiring such intervention. Dr. Illig and colleagues suggest that there are likely both cultural and ana-
bc
36 Creating aPercutaneous Arteriovenous Fistula: Evidence andTechniques
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a
d
387
Fig. 36.5 (a–d) Angioplasty of pAVF with radial access can allow dilatation of both outow and inow separately or simultaneously if needed
with dual access reproduced with permission from Mallios etal. J Vasc Surg [16]
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K. M. Bennett and A. Mallios
tomic differences. Anatomic differences can be attributed to
both relative rates of obesity and availability of usable supercial upper-arm veins. Cultural distinctions may be found in
the expected rate of ow during dialysis sessions (for-prot
dialysis centers vs. socialized health care) and cannulation
practices.
Status ofUse
While both devices have received both FDA approval and
EU CE mark, this does not translate directly into reimbursement or insurance coverage. The original WavelinQ
(Everlinq at the time) 6 Fr system CE marked in Europe in
2014 while the lower-prole 4 Fr verson received its marking in 2017. Ellipsys was CE marked in Europe in 2016.
Both the original WavelinQ and the Ellipysis cleared the
FDA in 2018 while the 4 Fr WavelinQ was FDA approved
in 2019. From a production and marketing standpoint, the 4
Fr version superseded the 6 Fr version as a means to
decrease the potential for brachial artery complications [13,
23].
In April of 2020 WavelinQ-4 Fr experienced a companyinitiated “urgent medical device recall notication” related
to issues with the magnets which translated into failure of
catheter alignment [23, 24].
In the US, CMS initially reimbursed both the 6 Fr version
of the WavelinQ and the Ellipsys system. Shortly after supplanting of the 6 Fr WavelinQ by the 4 Fr device, Center for
Medicare and Medicaid Services (CMS) stopped reimbursement for WavelinQ though continues to reimburse for
Ellipsys. CMS documentation delineates the reasoning
behind non-coverage of the WavelinQ system as the requirement for more robust evidence in terms of patient number
and duration of follow-up [23].
Some off-label uses of pAVF devices have also been
described. Mallios etal. described use of the Ellipsys device
for both a revision of dialysis arteriovenous stula using
distal inow (RUDI) and for creation of radio-radial stulas
(with delayed brachial vein elevation in patients with poor
supercial venous options) as well as for radiocephalic stulas at the wrist in select patients [25–27].
References
1. Food and Drug Administration US.FDA permits marketing of rst
catheter-based systems used to create vascular access for hemodialysis patients. US Food and Drug Administration; 2018.
2. Mallios A, et al. Midterm results of percutaneous arteriovenous
stula creation with the Ellipsys vascular access system, technical
recommendations, and an algorithm for maintenance. J Vasc Surg.
2020;72(6):2097–106.
3. Shahverdyan R, et al. Comparison of outcomes of percutaneous
arteriovenous stulae creation by Ellipsys and WavelinQ devices.
J Vasc Interv Radiol. 2020;31(9):1365–72.
4. Jennings WC, Mallios A, Mushtaq N.Proximal radial artery arteriovenous stula for hemodialysis vascular access. J Vasc Surg.
2018;67(1):244–53.
5. Tordoir JH, Dammers R, van der Sande FM.Upper extremity ischemia and hemodialysis vascular access. Eur J Vasc Endovasc Surg.
2004;27(1):1–5.
6. Wu CC, etal. The outcome of the proximal radial artery arteriovenous stula. J Vasc Surg. 2015;61(3):802–8.
7. Berland TL, Clement J, Grifn J, Westin GG, Ebner A.Endovascular
creation of arteriovenous stulae for hemodialysis access with a 4
Fr device: clinical experience from the EASE study. Ann Vasc Surg.
2019;60:182–92.
8. Illig KA, et al. The role of surgery for assisted maturation after
endovascular and percutaneous arteriovenous stula creation. J
Vasc Access. 2021;22(5):822–30.
9. Popli K, Dittman JM, Amendola MF, Plum J, Newton DH.Anatomic
suitability for commercially available percutaneous arteriovenous
stula creation systems. J Vasc Surg. 2021;73(3):999–1004.
10. Hull JE, Velez JH, Martinez JP. Percutaneous proximal radial
artery arteriovenous stula creation for hemodialysis using the
Ellypsis(TM) vascular access system. In: SIR 2014 annual scientic meeting program: convergence. San Diego, CA; 2014. p. S20.
11. Mallios A, Fonkoua H, Allouache M, Boura B.Percutaneous arteriovenous dialysis stula. J Vasc Surg. 2020;71(4):1395.
12. BD/TVA Medical. WavelinQ EndoAVF System Instructions for
Use (IFU). 2018.
13. Berland T, et al. Percutaneous arteriovenous stula creation with
the 4F WavelinQ EndoAVF system. J Vasc Surg. 2022;75(3):1038–
46. e1033.
14. Abdel Aal AK, etal. Devices and techniques for percutaneous creation of dialysis arteriovenous stulas. Semin Intervent Radiol.
2022;39(1):66–74.
15. Mallios A, etal. Early results of percutaneous arteriovenous stula creation with the Ellipsys vascular access system. J Vasc Surg.
2018;68(4):1150–6.
16. Franco G, Mallios A, Bourquelot P, Jennings W, Boura
B.Ultrasound evaluation of percutaneously created arteriovenous
stulae between radial artery and perforating vein at the elbow. J
Vasc Access. 2020;21(5):694–700.
17. Hull JE, et al. The pivotal multicenter trial of ultrasound-guided
percutaneous arteriovenous stula creation for hemodialysis access.
J Vasc Interv Radiol. 2018;29(2):149–58. e145.
18. Lok CE, et al. Endovascular proximal forearm arteriovenous stula for hemodialysis access: results of the prospective, multicenter novel endovascular access trial (NEAT). Am J Kidney Dis.
2017;70(4):486–97.
19. Zemela MS, Minami HR, Alvarez AC, Smeds MR. Real- world
usage of the WavelinQ EndoAVF system. Ann Vasc Surg.
2021;70:116–22.
20. Hull JE, etal. Long-term results from the pivotal multicenter trial of
ultrasound-guided percutaneous arteriovenous stula creation for
hemodialysis access. J Vasc Interv Radiol. 2022;33:1143.
21. Arnold RJG, etal. Comparison between surgical and endovascular hemodialysis arteriovenous stula interventions and associated
costs. J Vasc Interv Radiol. 2018;29(11):1558–66. e1552.
22. Yang S, Lok C, Arnold R, Rajan D, Glickman M.Comparison of
post-creation procedures and costs between surgical and an endovascular approach to arteriovenous stula creation. J Vasc Access.
2017;18(Suppl. 2):8–14.
23. CMS.Percutaneous arteriovenous stula (pAVF) for hemodialysis.
2020.
36 Creating aPercutaneous Arteriovenous Fistula: Evidence andTechniques
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24. FDA.Class 2 Device Recall WAVELINQ 4F EndoAVF System.
2020. https://accessdata.fda.gov/scripts/cdrh/cfdocs/cfRES/res/
cfm?id=17904.
25. Mallios A, Bourquelot P, Harika G, Boura B, Jennings
WC.Percutaneous creation of proximal radio-radial arteriovenous
hemodialysis stula before secondary brachial vein elevation. J
Vasc Access. 2021;22(2):238–42.
26. Mallios A, Jennings WC.Endovascular revision using distal inow:
EndoRUDI.Eur J Vasc Endovasc Surg. 2020;60(1):144.
27. Mallios A, Nelson PR, Franco G, Jennings WC. Creating percutaneous radiocephalic arteriovenous stulas at the wrist. J Vasc
Access. 2021;22(2):299–303.
Vascular Access
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T.Turlejski, I.Mandal, T.Barge, andR.Uberoi
37
Case Presentation
A 40-year-old male was diagnosed with chronic kidney disease secondary to poorly controlled diabetes. Due to a continued decline in renal function, he required haemodialysis.
Access was initially obtained via right internal jugular Tesio
lines (Fig.37.1) to facilitate dialysis, whilst a surgical arteriovenous stula could be formed and matured.
Continued at page 405
Fig. 37.1 Right internal jugular Tesio lines, with their tips in the right
atrium
T. Turlejski · I. Mandal · T. Barge · R. Uberoi (*)
Department of Radiology, John Radcliffe Hospital, Oxford, UK
e-mail: tymoteusz.turlejski@ouh.nhs.uk; indrajeet.mandal@ouh.
nhs.uk; thomas.barge@ouh.nhs.uk; raman.uberoi@ouh.nhs.uk
Introduction
Vascular access is critical to delivering a wide range of treatments, including intravenous medication, intravenous nutrition, repeated blood sampling and haemodialysis. Although
access has been performed blind in limited circumstances,
image guidance has become the standard of practice to optimise safety and technical success of the procedure. Various
anatomical locations and devices can be chosen, depending
on the clinical indication and patient-specic factors,
although there are many overlapping principles related to the
insertion of these devices. This chapter will summarise the
principles underlying the techniques, site selection and
equipment, and discuss techniques to manage challenging
cases.
Principles ofVascular Access
Veins can be classied as central or peripheral based on their
proximity to the heart. Central veins include the superior and
inferior venae cavae, brachiocephalic veins, subclavian veins
(SCVs), common and external iliac veins. These vessels are
of large calibre, usually with high ow rates, and typically
have minimal valves. Consequently, a catheter with its tip
placed in a central vein can be used to deliver venotoxic
medications such as chemotherapeutics or parenteral nutrition, achieve high ow rates required for haemodialysis or
allow the measurement of central venous pressure—an estimate of the pressure within the right atrium.
Whilst centrally placed devices have advantages (in particular longevity), they are technically more difcult to place
than peripheral devices, such as intravenous cannulas. Most
venous access is therefore obtained with peripheral devices,
which usually do not need image guidance and are placed at
the bedside. Peripherally inserted central catheters (PICCs)
are long lines inserted through a peripheral vein (typically
the basilic or brachial), with the tip terminating in a central
vein, usually the superior vena cava (SVC). These are quick
© The Author(s), under exclusive license to Springer Nature Switzerland AG 2024
G. Geroulakos et al. (eds.), Mastering Endovascular Techniques, https://doi.org/10.1007/978-3-031-42735-0_37
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T. Turlejski et al.
and relatively easy to insert and have become a common
method to obtain central venous access.
Image Guidance
Image guidance is essential to plan the procedure, select a
target and assess neighbouring structures. If available, prior
imaging should always be reviewed. Ultrasound (US) guidance remains the gold standard, enabling real-time visualisation of the needle and assessment of the vessel (incl. ow
with Doppler imaging) [1].
Broadly, two techniques can be used for US-guided vascular access: ‘in plane’ (with the probe oriented longitudinally along the course of the vein) and ‘out of plane’ (with
the probe oriented perpendicularly to the vessel length). The
former allows direct visualisation of the entire needle within
the scan plane from skin entry to venous puncture. In the latter, only a small dot representing the cross-section of the
needle can be identied, and care must be taken to accurately
determine the angle of puncture relative to the depth of the
vein. Mastering both approaches is crucial to establishing
successful access in various situations, for example, where
anatomical constraints prevent use of the in-plane technique
due to the size of the probe footplate, in which case the outof- plane method must be used.
Fluoroscopy is another useful modality and essential for
more difcult central line access placement. It allows visualisation of the course of the wire and/or catheter in the central venous tree, which cannot be visualised with US. If
available, uoroscopy can be used to ensure accurate tip
placement at the time of insertion and is essential in challenging situations, such as navigating central venous stenoses, which is discussed later. Fluoroscopy is however not
mandatory and is infrequently used in most central venous
catheter insertions performed outside of the angiography
suite, such as central lines inserted in theatre or PICCs
inserted at the bedside. In these cases, landmark measuring
techniques can be used to estimate the position of the tip, and
the nal position may be subsequently conrmed on a radiograph after insertion.
Central Access
Internal jugular vein (IJV), external jugular vein, subclavian vein and femoral vein can all be used for central vascular access. The IJV is the vessel of choice (for both
tunnelled and non-tunnelled lines) as it is associated with a
lower risk of thrombosis and pneumothorax, especially
compared to the subclavian vein [2]. The incidence of the
latter can be signicantly reduced by ensuring the needle
tip is always visible under US guidance, and there is evidence it may be comparable at both access sites [3]. The
right IJV is generally preferred due to its straighter course
to the heart.
For IJV access, the patient should ideally be placed in a
Trendelenburg position (supine with head slightly below the
level of lower extremities), with the head turned away from
the side of the target vessel. Image guidance with US is
essential for safe IJV access due to its proximity to the common carotid artery. The IJV should be compressible,
increase in diameter with the Valsalva manoeuvre and lie
lateral to the common carotid in the majority of cases,
although there is common anatomical variation, with some
studies reporting medial position in up to 5.5% of patients
[4, 5]. External jugular or subclavian veins can be considered if IJV access is deemed unsuitable (e.g. due to a thrombus). SCV access is commonly performed without image
guidance due to the position of the overlying clavicle impeding US visualisation. However, the vessel is often seen on
the US more laterally and can therefore be accessed with
image guidance at this point. The rate of pneumothorax is
greater with SCV access, partly as the landmark technique
is often used. However, judicious use of the US can reduce
this occurrence [3].
Similar principles should be applied with other sites for
central venous access, including the femoral vein. The femoral vein typically lies medial to the femoral artery. Apart
from being a common access site for intravenous procedures,
use of the femoral veins is only used in emergency settings
or as a last resort if attempts at other sites have failed.
Femoral vein access is however associated with a higher risk
of infection and is considered a less comfortable position for
long-term access for the patient.
Site ofAccess
The selection of site for vascular access is determined by the
target of the procedure and patient characteristics, such as the
presence of surgical incisions, scarring, skin infection, vessel
occlusion or anatomical variants. Although image guidance
with US remains the standard of care, direct palpation and use
of anatomical landmarks should also be utilised.
Peripheral Access
Peripheral veins typically used for PICC line insertion are
generally restricted to the veins of the (typically nondominant) upper extremity, with a preference given for the
basilic vein. Although the brachial vein is a suitable candidate due to its size, it is usually the second choice due to the
risk of injury to the adjacent brachial artery or median nerve.
The cephalic vein provides the least suitable access point due
to its smaller calibre and more tortuous path.
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Types ofLines andPorts
The technique, site and equipment are determined by the
specic purpose for which vascular access is established.
The factors to consider include the expected time the
line/catheter will be required for, as well as the size, number
of lumens, maximum ow rates or injectable pressures
required. The latter is an important consideration if power
injectors may be used, such as pumps used to administer iv
contrast for CT scans. These parameters are dened by the
specic clinical need, and line selection should be determined on a case-by-case basis. A summary of the commonly
used devices is outlined in Table37.1.
A central line can take many forms, but essentially the
denition is that the line tip ends within the central venous
system. Usually, this is at the cavoatrial junction (the junction of the SVC and right atrium). The venous insertion site
varies and can be peripheral (PICC line) or central (nontunnelled CVC, tunnelled lines and ports).
Central veins have a higher ow compared to peripheral
veins, which not only allows the delivery of higher ow rates
of infusions (e.g. for haemodialysis) but also helps to dilute
the medications. The latter is particularly helpful with more
toxic agents, which could cause signicant damage if given
via peripheral veins. Conversely, a peripheral line is one
where the line tip ends in a peripheral vein.
Peripheral Lines
Peripheral lines are very common. Most hospitalised patients
will have a standard peripheral IV (commonly referred to as
a ‘cannula’). Midlines are also peripheral lines, but the tip
lies in the axillary vein—this is larger than the smaller
peripheral veins. The advantages of a midline compared to a
peripheral IV are that they are more stable, can be used for
longer and are available in two lumen congurations.
Central Lines
A peripherally inserted central catheter (PICC) is the
only type of central access where the insertion site is into a
peripheral vein (Fig.37.2). PICC lines allow central access,
and the advantage of peripheral insertion site means there is
a lower risk of serious complications from line insertion.
However, PICC lines are smaller in size, as the line needs to
be small enough to insert into a peripheral vein.
Non-tunnelled central venous catheters (CVCs) are the
main method used in acute critical care settings. Often these
are referred to as ‘central lines’. These carry a higher risk of
bloodstream infection, so a line should be used only for
7–10 days. There are multiple different types of line, but
typically they are multi-lumen catheters. CVCs with larger
lumens can be used for temporary haemodialysis. They are
typically of larger diameter compared to other CVCs to
accommodate the large luminal diameters of the afferent and
efferent limbs; this is critical to enabling the high ow rates
required and is related to Poiseuille’s law, which states that
the ow of uid through a lumen is related to the radius of
the lumen to the power 4. Consequently doubling the diameter of a lumen increases its ow rate by 16 fold.
Tunnelled lines are a CVC, but the line is tunnelled from
the venotomy site subcutaneously to exit at a different site in
Table 37.1 Commonly used types of venous catheter
Indications Type Details of use Examples
Peripheral
catheters
Central
catheters
• Parenteral delivery of nutrition
• Antibiotics
• Analgesics
• Chemotherapy
• Repeated blood transfusions
• Administration of IV uids or
medications
• Delivery of blood products, either in
large quantities or over a prolonged
period of time
• Administration of medications that are
harmful to peripheral veins (e.g.,
chemotherapy)
• Long-term access to the central
venous system for repeated
procedures, such as blood sampling
• Poor or inaccessible peripheral venous
access
• Emergent placement of central lines
Peripheral
intravenous access
(PIV)
Midline catheter For short-term access (usually
Peripherally inserted
central catheter
(PICC)
Non-tunnelled central
catheter
Tunnelled central
catheter
Implantable port For infrequent long-term access Port-a-cath
For short-term access (usually up
to 1week)
1–4weeks)
For medium-term access (usually
1month to 1year). Not
recommended for dialysis.
Short-term access when PIV not
suitable—e.g. uid resuscitation or
CVP monitoring
For frequent long-term access
when PICC not suitable
Venon
Single- or doublelumen options
available
Single-, double- or
triple-lumen options
available
Multi-lumen CVC
(one to ve lumens)
Vas Cath (large
diameter, used for
dialysis)
Hickman line (one to
three lumens), Tesio
line
Perm Cath
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Fig. 37.2 Left-sided PICC line inserted into the basilic vein, with the
tip appropriately sited in the SVC
T. Turlejski et al.
the skin. The tunnelling lowers the risk of infection and
increases the line stability, allowing the line to be used for
longer-term access. The lines have an incorporated cuff,
which promotes brosis and tethers the line in the subcutaneous tissues. Tunnelled lines require a high degree of care in
the community—the lines need to be frequently ushed and
dressed. They may also be inconvenient for the patient as the
lumens lie usually on the anterior chest wall and are cosmetically obvious. The most common indications for tunnelled
lines is haemodialysis and parenteral nutrition—these
patients require long-term venous access. In general, for
other indications that require long-term venous access where
a PICC is not appropriate, a port may be preferable (see
below).
Ports are effectively tunnelled lines, but at the end of the
line, there is a reservoir attached to it (Fig.37.3). The reservoir is buried in a pocket under the skin. They offer several
advantages compared to tunnelled CVCs. Ports require less
catheter maintenance in the community, and the line is more
cosmetically discrete and may cause less disruption to the
patient. They also carry a lower infection risk [6].
Additionally, the port site can be varied according to the
patient’s needs, e.g. it can be placed peripherally in the arm
compared to the chest wall, although peripherally placed
ports carry a higher thrombosis risk [7].
The main disadvantage of ports is they require specialist
input to needle the chamber and access the circuit. Ports are
also slightly more challenging to insert and remove compared to tunnelled lines. However, for patients requiring
long-term access, it may be overall more cost effective to
Fig. 37.3 Right-sided single-lumen port inserted into the right internal
jugular vein, with the tip of the catheter at the cavoatrial junction
place a port rather than a tunnelled line when taking into
account the cost of community care for tunnelled CVCs.
Complications
The risk of complications associated with venous access is
less signicant compared to arterial access due to thinner
vessel walls and lower intraluminal pressures. The risks can
be further minimised by the appropriate use of ultrasound
and uoroscopic guidance. Still, they are important to be
aware of as they can be serious and potentially fatal.
Early Complications
• Pneumothorax and haemothorax—a rare but critically
important complication of vascular access occurring in
less than 1 in 10,000 cases. Traditionally pleural injury
was considered more common with subclavian access
compared to IJV access; however the adoption of US
guidance as a standard of practice allowed to minimise
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the risk to comparable levels in the hands of experienced
operators [3]. Pneumothoraces can be identied on uoroscopy or on post-insertion CXR—small pneumothoraces can be managed conservatively, while larger ones may
require chest drain insertion.
• Accidental arterial puncture—usually identied immediately as pulsatility of blood return from the vessel and
by identifying the incorrect positioning of the needle/wire
in the artery on the US.In case of uncertainty uoroscopic
assessment can be used to conrm anatomy.
• Haematoma—usually seen in coagulopathic patients.
• Air embolism—rare emergency, caused by entrainment
of air into the central venous system, which may translocate to the right heart and severely impair right ventricular
output, leading to potentially fatal consequences. Sudden
onset of tachycardia, shortness of breath, chest pain or
confusion should prompt an immediate assessment, oxygen therapy and placement in left lateral decubitus or
head-down position. Some devices contain a one-way
valve that prevents air entry, but it is a safe practice to
reduce the risk of air entry by covering any large-bore
catheter, needle or dilator with a nger to prevent air from
getting sucked in.
• Catheter malposition—Inappropriate positioning of the
catheter tip can occur and is more likely if real-time uoroscopic guidance is not used. For example, blind wire
insertion via the IJV can inadvertently pass into the SCV,
rather than BCV/SVC, leading to the tip of the CVC lying
in an incorrect location. Similarly, catheter tips placed at
venous conuences can result in the tip abutting the vessel wall and impeding aspiration through the lumen.
Inappropriate tunnelling is also important, as acute curves
can lead to line kinking and impede luminal function. The
vast majority of these can be identied on real-time uoroscopy or on post-procedural radiographs. The advantage of the former is that catheter malposition can be
rectied at the time of insertion.
• Fibrin sheath—due to accumulation of brous material
at the tip with long-term vascular access. Many catheters
will eventually develop this, in most cases without any
clinical signicance. It may, however, cause a blockage,
especially if there is concurrent intraluminal thrombosis,
in which case tPA or urokinase infusion can be used in an
attempt to unblock it. Manipulation with a wire, stripping
with a snare under uoroscopic guidance or over-the-wire
replacement can also be used for this purpose if the catheter remains blocked.
• Line entrapment or fracture—entrapment of the catheter between the clavicle and the rst rib may occur with
1in 100 subclavian catheters [8]. Over time, it leads to
catheter fracture due to repetitive injury, particularly in
the setting of long-term access. The damaged catheter can
leak its contents into the surrounding tissues and, in rare
cases, detach completely, subsequently migrating into
and embolising into the distal vasculature. Hence, this
complication needs to be recognised early. Patients may
complain of local discomfort and swelling due to uid
extravasation. The operator may notice positional difculty in injection (easier with patient supine with ipsilateral arm raised). Classically, the scalloping of the catheter
can be seen on a plain chest radiogram.
• Infection—can occur at the exit site, the tunnel or in the
bloodstream (the latter associated with high mortality).
Management depends on the type, but line removal or
replacement is usually required if the catheter has become
colonised. The incidence of catheter-associated bloodstream infections has been reported as 2.2–2.79 infections
per 1000 catheter days, with a recent meta-analysis
reporting a slightly lower risk if access was obtained with
US guidance [9].
• Catheter displacement or accidental removal.
Dicult Situations andTroubleshooting
Late Complications
• Catheter-related thrombosis (CRT)—occurs due to
endothelial damage and venous stasis, frequently associated with a hypercoagulable state (particularly in cancer
patients). The risk is increased in left-sided catheters and in
the event of catheter malposition. Most patients are asymptomatic, but some may present with signs and symptoms of
upper limb DVT. Like DVT, CRT is associated with a high
risk of PE or post-thrombotic syndrome, so there is a low
threshold for further investigation if CRT is suspected. It is
worth noting that a concern of CRT is often raised on crosssectional imaging, where a true CRT cannot be reliably distinguished from a brin sheath (below).
Central vein stenosis is a common nding in patients who
have a history of multiple venous lines in the past, particularly in patients on haemodialysis. Venous access in these
patients is more technically challenging and may require
adjunctive techniques to secure adequate catheter
positioning.
Patients with a history of repeated and/or multiple venous
insertions should undergo cross-sectional imaging (most
commonly with a CT venogram but MRV may be utilised) to
evaluate the veins for stenoses or occlusion. This imaging
allows for optimal pre-procedure planning. This will help to
determine whether adjunctive techniques to insert a line
using a more conventional location, such as venoplasty/
recannalisation of a central vein, are required or whether an
alternative access site should be sought.
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