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24 Safe and strategic vascular access

pushing the needle through the back wall of the

graft, especially if the graft is not yet well incor-

porated. A 4-Fr micropuncture set is useful for

this task. If the graft is resistant to advancement

of the 4-Fr dilator, advance the 3-Fr trochar or

inner dilator and then gradually upsize until the

desired sheath is in place. Attempt to minimize

the size of the sheath since closure is not usually

performed for hemostasis.

Percutaneous puncture may also be performed

on a prosthetic gra that is immediately subcu-

taneous. e most common situation that calls

for this is evaluation of a dialysis access gra.

Occasionally, an axillofemoral, femoral–femoral,

or infrainguinal bypass gra requires direct punc-

ture. Local anesthetic is injected into the skin and

subcutaneous tissue over the gra. No skin inci-

sion is made. e needle tip is used to puncture the

skin and travel several millimeters in the subcuta-

neous tissue parallel to the gra. e needle hub is

then tipped away from the skin so that the needle

is at a 45-degree angle to the gra. e tip of the

needle is then inserted into the gra. is maneu-

ver creates a short subcutaneous tract that will help

protect the gra from infection. It also helps with

hemostasis. e needle should be introduced at

45 degrees or more to avoid a larger, oval-shaped,

or skiving type of puncture site hole in the gra,

which may be more dicult to control. Aer the

guidewire is placed, introduce the smallest caliber

catheter that is adequate for the intended purpose.

Since these puncture sites are usually away from

anastomoses, they are less subject to extensive

scarring around the gra.

Occasionally, a femoral artery that serves as

inow for an autogenous infrainguinal bypass

gra requires puncture. Aim for the hood of the

gra or more proximally along the artery. e

hood of the gra is usually where the pulse is felt

most easily. Use clips and any femoral calcication

seen on uoroscopy as landmarks.

PUNCTURE SITE COMPLICATIONS

The most common type of complication in endo-

vascular care is related to access. Complications

of arterial puncture are listed in Table 2.2. The

rates presented were accumulated using various

techniques but do not include those patients who

have undergone closure procedures at the punc-

ture sites. The worst complications the author

has seen are side branch punctures and side wall

punctures.

SUMMARY OF PUNCTURE SITE

OPTIONS AND CLOSURE STRATEGY

Puncture site options and their relative rates

of risk are summarized in Table 2.3. e retro-

grade femoral puncture is by far the most com-

mon and the most useful approach. Antegrade

femoral puncture is limited in its use to the

Table 2.2 Complications of femoral artery puncture and catheterization

Complication

Frequency

(%)

SCVIR complication

threshold (%)

Minor bleeding or hematoma 6.0–10.0

Major bleeding or hematoma (requiring transfusion, surgery, or

delayed discharge)

1.0–2.4 3.0

Pseudoaneurysm 0.5–5.0 0.5

Arteriovenous ﬁstula 0.01–0.1 0.1

Occlusion (thrombosis or dissection) 0.3–1.0 0.5

Perforation <0.5

Distal embolization <0.5

Infection <0.1

From Valji K. Standard angiographic and interventional techniques. In: Valji K, ed. Vascular and Interventional

Radiology. Philadelphia: WB Saunders, 1999:12–17 and Brown MA, Nemcek AA, Vogelgang RL. Interventional

Radiology Procedure Manual. New York: Churchill Livingstone, 1997:68.

From Spies J, Bakal C, Burke D et al. Standards for diagnostic arteriography in adults. J Vasc Intervent Radiol 1993;

4:385–395.

Abbreviation: SCVIR, Society of Cardiovascular and Interventional Radiology.

https://t.me/med1917

Summary of puncture site options and closure strategy 25

ipsilateral infrainguinal arteries; however, this

is the preferred approach for complex tibial

and pedal reconstruction. Proximal puncture

sites in the brachial or axillary arteries are used

whenthere is no adequate femoral puncture site or

when there is some anatomic advantage of a prox-

imal approach (e.g., superior mesenteric artery

stent). Right from the start of the case, you have

to be thinking about how the access will be closed.

Closure devices are indicated for retrograde femo-

ral puncture of the native artery. Many operators

have also used closure devices for antegrade femo-

ral, prosthetic gra, and brachial artery closure.

In general, closure should be considered in every

case. In situations of a diagnostic angiogram only

and a 4-Fr or 5-Fr sheath access, the operator may

elect to perform manual compression. For most

therapeutic cases, if the patient is a candidate for a

closure device, this is the simplest and safest way

to proceed. Ultrasound is extremely helpful for

assessing the potential of closure device usage and

also for increasing the likelihood that the device

will be successful by choosing the puncture site

very accurately. It is best not to be too close to

the inguinal ligament as the closure device going

through the ligament can become dislodged at a

later time. It is also best to be in the body of the

artery and to be away from areas of heavily calci-

ed plaque or obstructive lesions. Closure devices

are discussed in more detail in Chapter 30.

Table 2.3 Comparison of puncture site options

Puncture Usefulness

Technical

difﬁculty

Overall risk of

signiﬁcant

complications

Comments

Retrograde

femoral

Most useful Simplest 1.7% More than 90% of cases may

be performed

transfemorally. It is the

simplest and has the

lowest complication rate

Antegrade

femoral

Useful for

ipsilateral

infrainguinal

arteriography or

intervention

Entering the

origin of the

superior

femoral artery

can be

challenging

A relatively safe approach.

Especially useful for

infrainguinal catheterization

in patients who have a

contraindication to crossing

the aortic bifurcation

Brachial Useful for

arteriography

and/or

intervention when

femoral access

not possible

challenging

than femoral

puncture but

simpler than

axillary

7.0% Smaller artery with tighter

neurovascular sheath.

Higher risk of neurologic

complications or distal/hand

ischemia. Consider open

exposure for sheath ≥6-Fr

Previously

placed

graft

Useful in patients

whose anatomy

is altered by

previous surgical

reconstruction

Perigraft scar

tissue can

make catheter

passage

difﬁcult

Administer prophylactic

antibiotics if graft is

prosthetic

Source: From La Berge Golden RL, Kerlan RK et al. Interventional Radiology Essentials. Philadelphia: Lippincott

Williams & Wilkins, 2000.

https://t.me/med1917

Sheath access

INTRODUCTION

At the initiation of every case, access must be

secured. e basic sheath provides access for

medication and contrast, is advanced over a

guidewire, may or may not have a radiopaque tip,

secures the access site, prevents bleeding during

the procedure, and is an access point where diag-

nostic or therapeutic catheters can be introduced

into the vascular system. Chapter 2 oered some

advice about choosing an access site and mak-

ing it safe. Routine use of ultrasound guidance

for access and needleplacement was also covered

in Chapter 2. Aer the access site is selected, the

access needle is placed in the artery and the initial

guidewire introduced. en what? e usual situ-

ation is to proceed with placement of a standard

access sheath followed by arteriography. A guiding

sheath or guiding catheter is typically placed when

the decision is made to treat a specic disease seg-

ment. Access for endovascular therapy is covered

in Chapter 14. Asheath is used on every case, from

diagnostic arteriography to complex interventions.

As soon as the needle is in the blood vessel, you will

be ready to place a wire. is chapter includes the

steps you need to take between when the needle is

placed in the artery and when the access is secure.

BASIC ACCESS SITE STEP-BY-STEP

Guidewires are discussed in Chapter 5. e guide-

wire you introduce initially through the access

needle in the artery is a compromise. It must be

sti enough to serve as an initial rail for sheath

passage. e tip of the guidewire must be atrau-

matic, so that if pathology is encountered, it is not

disrupted. e guidewire must be inserted into the

vessel for a sucient distance that the anchoring is

secure in the vascular system for sheath advance-

ment, and a more rm or sturdy portion of the wire

is available at the skin level over which to advance

the sheath. If tortuosity or disease is encountered, a

steerable guidewire is sometimes necessary. Access

is performed with 0.035-inch diameter guidewires.

In general, steerable guidewires in this platform,

such as the Glidewire

, do not have much sha

strength for sheath placement. A Bentson Wire

Guide, Newton Wire Guide, or Starter

Guidewire

is usually adequate for initial atraumatic guide-

wire placement. If there is a lot of scar or disease

in the groin, a slightly stier Rosen wire might be a

better choice, but the tip is stier and a little more

traumatic. If a Glidewire

is needed, the author

usually exchanges it out using a 4-Fr dilator and

places a stier guidewire for sheath placement.

e author routinely uses micropuncture tech-

nique, as described in Chapter 2. Aer placement

of the 21-gauge micropuncture needle, the 0.018-

inch wire (which comes with the set) is advanced.

e 4-Fr or 5-Fr dilator with the micropuncture

is advanced. At that point, the 0.035-inch wire

selected by the operator is advanced.

As soon as the 0.035-inch introducing guide-

wire is in place, a basic access sheath must be read-

ily available. Arteriography through a 4-Fr or 5-Fr

catheter requires a 4-Fr or 5-Fr sheath, respec-

tively. If an intervention is already planned and the

anatomy already examined, prepare and deploy a

sheath through which to perform therapy. is is

faster and smoother than placing a small caliber

sheath and upsizing later. If there is a chance that a

therapy may be precluded by some anatomic detail

that will be revealed during the arteriographic

study, then go with a smaller sheath, initially for

https://t.me/med1917

28 Sheath access

diagnostic purposes only, so that a minimally sized

puncture site is created.

INITIAL MANEUVERS TO SECURE

THE ACCESS

Aer the guidewire is in place, some operators

use dilators on a regular basis and some do not.

Dilators are discussed in the section “When is a

dilator needed?”. Hold pressure on the groin when

the guidewire is alone across the arteriotomy. is

helps to prevent blood from accumulating under

the skin and around the puncture site in between

dilator or catheter exchanges. When the needle is

in the artery with the guidewire going through it,

do not hold pressure. e needle is rigid and push-

ing on it may cause it to dislodge or cause the nee-

dle tip to injure the artery.

Aer the guidewire is in the artery, it is

advanced away from the entry site. e guidewire

must be advanced through the entry needle and

into the artery at least far enough so that the oppy

tip portion of the guidewire has cleared the entry

site. Fluoroscopy is initiated and the guidewire is

advanced into the desired location. If resistance

is met by the guidewire, stop pushing and initiate

uoroscopy to help guide the process and avoid

injury. Pressure at the puncture site is held as the

needle is removed. e guidewire is wiped with

heparin–saline-soaked gauze or Telfa.

A dilator is placed. If a skin incision is desired, it

is best to perform the incision directly over the dila-

tor (Figure 3.1). Usually any sheath larger than 5-Fr

is placed more easily with a small skin incision. e

dilator is a hard material, is inexpensive, and will

be discarded aer the access is achieved. A surgi-

cal No. 11 blade can be placed directly on the dila-

tor and the dilator over the guidewire may be used

as a rail. is way the incision may be minimized.

When the incision is performed over the guidewire

itself, it is usually done blindly since blood comes

out of the access site and pools at this location.

When the puncture site incision is made over the

sha of the sheath, the blade can easily cut the thin-

walled sheath and it will leak until it is replaced.

When using dilators, go for the same French

number size as that of the sheath (this is a dilator

that is one size outside diameter (OD) smaller than

the sheath) or one size larger than the sheath (this

is a dilator that is the same size OD as the sheath).

If it is a scarred groin or the artery is calcied, use a

dilator with an OD the same size as the sheath (one

number size larger).

HOW DO YOU PLACE A SHEATH?

Aer the sheath is selected, the dilator for the

sheath and the sheath itself are each ushed and

wiped with heparinized saline. e stopcock on

the side arm is turned to the “o” position. Before

placing the sheath, double-check that you have

the desired size in hand. Lock the dilator hub in

place so that the dilator does not back out while

the sheath is being advanced. Check the skin inser-

tion site to see if the incision needs to be enlarged

slightly. is can be done with a mosquito clamp.

Conrm that the guidewire in place is sti enough

to facilitate sheath placement. Sheaths can usually

Fig. 3.1 Making a skin incision at the entry site.

It is important to minimize the size of the incision

to just what is needed for the case. (A) After the

guidewire is placed and conﬁrmed to be in the

artery, a 4-Fr or 5-Fr dilator is advanced over the

wire. (B) When the dilator is withdrawn slightly,

it “tents” up the skin and draws out the tissue

immediately surrounding the puncture site.

(C)Ascalpel is used to incise the skin directly

over the dilator. A 6-Fr sheath requires a 2-mm

opening in the skin. A10-Fr sheath requires a

3-mm opening. The dilator will be discarded

and it is much more resistant to a scalpel cut

than a usual sheath. Bleeding from the skin itself

at the entry site is a common cause of concern

and repeat visits for the patient and phone calls

for the physician. Do this carefully and minimize

theincision to only what is needed.

https://t.me/med1917

How do you place a sheath? 29

be placed using a starting guidewire. If the sheath

is large, long, or passing through a scarred groin,

consider a stier guidewire. Make sure that which-

ever guidewire is in place has been advanced far

enough so that the oppy tip is well inside the

patient and that the artery entry site is crossed with

the stier portion of the sha of the wire.

Gradual, stepwise enlargement of the tract

and artery entry site with dilators is not always

required, but is the cleanest way to place a sheath

(Figure 3.2). If the sheath is upsized by two French

sizes or more, dilators should be used. When plan-

ning sheath placement through a dicult entry site

(e.g., a scarred groin or a previously placed bypass

gra), a series of vascular dilators should be used

to predilate the entry site to one French size larger

than the label on the sheath. is eases placement

and helps prevent a buckle at the tip of the sheath,

which can damage the arteriotomy site and unnec-

essarily enlarge it. In between passing each dilator

and, eventually, the passage of the sheath, pressure

should always be held at the puncture site to pre-

vent bleeding. Blood that accumulates under the

skin between each step forms the beginning of

a hematoma. If this is not managed diligently, at

some point in the case, especially aer anticoagu-

lation, it may not be clear if the patient is actively

bleeding at the puncture site. In addition, aer the

procedure, the only thing the patient will be able

to see is the puncture site. Minimizing blood col-

lection and ecchymosis at the puncture site is a

worthwhile endeavor.

e sheath is loaded onto the guidewire by an

assistant and advanced all the way to the entry

site. e guidewire is pinned by the assistant. e

operator maintains gentle manual pressure with

one hand at the access site and with the other hand

advances the sheath over the guidewire, through

the skin, and into the artery. Pressure is maintained

at the puncture site until the tip of the dilator or

the sheath is inside the artery to tamponade the

arteriotomy. e sheath is advanced by holding it

along its sha near its tip so that it does not buckle

as it goes through the skin. Sometimes it is helpful

to rotate the sheath back and forth to get through

the subcutaneous tissue. Place the side arm port in

a convenient orientation, usually toward the opera-

tor. Occasionally, when the sheath is advanced, the

dilator loosens at the hub and begins to back out. If

this occurs, the open end of the sheath will be push-

ing bluntly into the tissues and be damaged and

may also damage the artery. If this occurs, with the

dilator inadvertently backing out during advance-

ment of the sheath, stop advancing the sheath and

assess. If the sheath is not already inside the artery,

take it out and examine it. If the tip of the sheath

itself is damaged, get a new one. Pressure is main-

tained on the arteriotomy with the free hand until

the sheath can be felt going into the artery. Aer

the tip of the sheath clears the arteriotomy, there

is usually minimal resistance during advancement.

e hand advancing the sheath can usually sense

a “give” in the progress of the sheath, aer which

the sheath advances smoothly and easily. If there is

A C D EB

Fig. 3.2 Sheath placement. Sheath placement permits safe, simple, and hemostatic access.

(A)Aguidewire is placed in the infrarenal aorta. (B) The femoral arteriotomy is dilated using the

dilator appropriate to the sheath intended for placement. (C) Digital pressure is maintained over the

arteriotomy to prevent hemorrhage after the dilator is removed. (D) The dilator is placed within its

sheath and the dilator–sheath combination is advanced over the guidewire. Slight pressure at the

puncture site prevents buckling of the sheath. The sheath–dilator apparatus can be rotated as it is

advanced. (E)After sheath placement, the dilator is removed and the sheath ﬂushed.

https://t.me/med1917

30 Sheath access

resistance, something may be wrong. Use uoros-

copy to evaluate. Occasionally, the tip of the sheath

becomes damaged and irregular and catches on

the artery as it is advanced. Sometimes, this dam-

age to the sheath is severe enough that the sheath

must be discarded and a new one placed to avoid

damaging the artery. Once the sheath tip is in the

artery, advance it to its hub.

Aer the sheath is placed, take out the dilator

that comes with the sheath, aspirate through the

side arm port, and ush with heparinizedsaline.

Aer administering contrast through the sheath,

it should be ushed. When you ush the sheath

with a syringe, point the syringe inferiorly

(toward the oor) to avoid getting air into the

sheath. e sheath should also be ushed inter-

mittently throughout any case. Occasionally, a

continuous slow infusion of heparinized saline

using a pressure bag is required to keep the sheath

clear. Ifthere is bleeding around a sheath during

the case, apply gentle pressure. If that does not

work, upsize the sheath to tamponade the tract.

If you upsize the sheath in this situation, use a

0.035-inch wire of adequate stiness, usually the

same wire that was used to permit sheath inser-

tion initially. If the sheath is withdrawn any sig-

nicant distance, to readvance it any further, its

dilator should be replaced before it is advanced.

If the so edges of the sheath tip have become

frayed during a placement attempt, place a dier-

ent one to avoid irregular tears at the arteriotomy

site. When a sheath is placed in a patient with

large and tortuous arteries, it tends to slide in and

out. If tortuosity is severe and is near the access

site, the sheath may start to back out on its own.

It is sometimes worthwhile to secure the sheath

with a stitch in the skin and around the hub to

avoid spontaneous sliding. If a catheter is placed

through the sheath that is labeled the same as the

sheath size (i.e., a 5-Fr catheter in a 5-Fr sheath), it

will not usually be possible to administer contrast

or heparinized saline through the side arm since

the catheter completely lls the sheath. When

performing interventions, you must know where

the sheath tip is located to avoid performing bal-

loon angioplasty or deploying a stent within the

sheath. When performing interventions, it is usu-

ally best to use a sheath with a radiopaque marker

at the tip. If the sheath tip is close to the treatment

site, the operator wants to avoid inadvertent bal-

loon angioplasty within the tip of the sheath.

Fluoroscopy is initiated as the catheter is

advanced over the guidewire past the sheath. When

lesions are encountered on the initial guidewire

pass, it is usually best to stop the wire advance and

secure the access site before crossing. If the guide-

wire is not far enough inside the artery to secure

the access, a careful attempt should be made to

cross the lesion. Guidewire and catheter exchanges

are dicult in this position, with the wire barely

inside the artery. Sucient guidewire must be

advanced into the artery so that the stier part of

the body of the wire is in the arteriotomy, in order

to support the advancement of a dilator. When a

lesion is encountered in the iliac artery during ret-

rograde femoral puncture and the guidewire does

not cross it, sometimes the wire can be looped on

itself distal to the lesion in order to get enough sti

wire length inside the artery to allow the stier

part of the wire to be at the arteriotomy site. If an

ipsilateral iliac lesion is anticipated, consider using

a long 5-Fr micropuncture. In this scenario, the

wire only has to cross the lesion once and the 5-Fr

access across the lesion will support the 0.035-inch

wire of choice.

If the access femoral artery is heavily calcied

or there is a lot of surrounding scar tissue, the

guidewire may well go into the artery, but there

may be signicant diculty in passing a dilator or

sheath over it. In this case, the tip of the dilator

may bounce o the diseased artery and the whole

system, guidewire and sheath, may begin to buckle

in the subcutaneous tissue. When the artery is

scarred in an obese patient, this scenario is even

more likely to occur, with the access sheath becom-

ing lost in the subcutaneous tissue. e operator

can push in a more downward direction to pass the

dilator, as if pushing toward the oor, so the dilator

approaches the artery at nearly a 90-degree angle.

e operator also guides the dilator and straightens

the guidewire in the subcutaneous tissue using the

nondominant hand (Figure 3.3). Aer the initial

dilator placement, the guidewire may be replaced if

a dierent one is required for negotiation of lesions

or if a stier wire is needed over which to advance

the sheath.

WHEN IS A DILATOR NEEDED?

Your best chance of a favorable puncture site is

the initial attempt. is is also the best opportu-

nity for an access site that can be managed with

https://t.me/med1917

When is a dilator needed? 31

a closure device – a straight tract of adequate size

leading to a smooth and regular shaped arteri-

otomy in a location along the anterior surface

of the healthiest part of the artery. Many of the

steps discussed so far, including, how to choose

the puncture site, use of ultrasound guidance

and micropuncture, and various things to do and

avoid, are all leading toward this goal. e last

step is to use dilators.

e use of dilators is unlikely to damage any-

thing, and in some cases may be of help. A 4-Fr

or 5-Fr sheath can usually be passed without dif-

culty. If there is a lot of periarterial scar or the

artery is heavily calcied, even a 4-Fr or 5-Fr sheath

may require use of a dilator. In general, the larger

the sheath, the more likely a dilator will help the

operator. Make sure the guidewire is still straight,

using uoroscopy, and that it is not twisted in the

subcutaneous tissue if there is any question. A dila-

tor may then be advanced to secure the entry site

and slightly dilate the tract. When the access site is

hostile, aer placement of the smallest dilator, usu-

ally 4-Fr, it is sometimes useful to replace the wire

with a sti exchange guidewire, such as an Amplatz

guidewire. When the operator is concerned about

the size of the sheath intended for placement or

the quality of the access site, it is appropriate to

initiate sheath placement using a dilator or even

a series of dilators. When endovascular therapy is

planned, the arterial access site may require sub-

stantial enlargement, to sheath sizes larger than

20-Fr. is is done by passing progressively larger

dilators over the guidewire (e.g., 6-, 8-, 10-Fr dila-

tors) until the site is adequately sized to accept

the intended therapeutic device. Since dilators

are sized by OD and sheaths are sized by inside

diameter (ID), a 7-Fr dilator is used to prepare

the tract for a 6-Fr sheath. Occasionally, in a very

scarred access site, it is necessary to place a dila-

tor that is one size larger than the intended sheath.

For example, an 8-Fr dilator may be required to

prepare the tract for a 6-Fr sheath. During sheath

A B

Fig. 3.3 Placement of the sheath in a calciﬁed, thickened, or scarred artery. (A) After guidewire

placement and enlargement of the subcutaneous tract, the sheath is advanced. (B) If the artery is

calciﬁed or thick walled, or there is surrounding scar tissue, the tip of the dilator will sometimes

bounce off the artery, instead of entering it. (C) The nondominant hand can be used to press the

tissues around the guidewire and guide the tip of the sheath into the artery.

https://t.me/med1917

32 Sheath access

placement, if the tip of the sheath hits signicant

resistance as it is being passed into the artery, it is

usually better to back o and take out the sheath

and place the dilator to prepare the way. Be sure

to inspect the tip of the sheath if the advancement

is aborted. Occasionally, the initial pass into the

subcutaneous tissue will result in tearing of the tip

of the sheath. Keep in mind that the dilators are

usually intended to prepare the tract and the arte-

riotomy, and usually do not need to be advanced to

the hub. Occasionally, dilators are used to “sound”

the artery, gently stretch the artery, or Dotter a

diusely diseased segment. is is a common

maneuver for obtaining access for larger vascular

devices such as stent–gra delivery catheters for

treatment of abdominal aortic aneurysm. In this

case, the dilator is usually advanced all the way

into the artery.

BASIC SIZING ISSUES

Sizing issues are confusing but they should be

considered prior to the case. erapeutic cases,

especially complex ones, may be a challenge with

respect to sizing. In this discussion, some of the

initial sizing issues are presented. More detail

about sizing can be found in Chapter 14. When

referring to sizing, the discussion is usually about

caliber. e length of each device is also important

and is discussed in multiple sections throughout

this text.

Guidewire diameter or caliber is measured in

inches. e number “035” refers to a guidewire

that is 0.035 inches in diameter. Guidewires are

described in Chapters 5 and 6. Available guidewire

sizes are 0.010, 0.014, 0.018, 0.025, 0.035, and 0.038

inches in diameter. Each guidewire caliber has

associated catheter sizes that are appropriate for

use with it. e most commonly used guidewires

are 0.14, 0.18, and 0.35 inches in diameter.

Dilator and catheter sizes are described using

the French system. is system is a description of

the caliber of the catheter. e French caliber mea-

suring system is based on pi (3.14), the number of

times that the diameter of a circle goes around the

outside of the circle to make up the circumference.

To convert from French measurement to the diam-

eter of the catheter or sheath, divide the sheath size

by pi or approximately 3. For example, the diam-

eter of a 6-Fr sheath is approximately 2 mm, or

6 divided by 3. e diameter of a 24-Fr sheath is

approximately 8 mm, or 24 divided by 3. To con-

vert a French size, divide by 3, and that is how big

the hole in the artery will be in millimeters.

Dilators and catheters are described by their

OD. Sheaths are sized by their ID. A sheath is

described by what will t through it. is is appro-

priate since the sheath serves as a conduit for intro-

ducing other devices into the vascular system.

A6-Fr sheath has a 2-mm diameter. When a sheath

is placed percutaneously, if it needs to be replaced,

it must always be exchanged for a sheath that is the

same French size or larger so that the artery does

not bleed around the sheath.

WHEN TO USE FLUOROSCOPY

Fluoroscopy–eye–hand coordination is a develop-

mental skill that must be gained by endovascular

specialists. All modern uoroscopic equipment

uses foot pedal controls. is introduces the poten-

tial for overuse and ineciency since plantarex-

ion and dorsiexion are required by the operator

intermittently throughout the case, oen while

both hands are working simultaneously.

Fluoroscopy is occasionally useful in plan-

ning the puncture. is is especially true for the

pulseless femoral artery or for antegrade femo-

ral puncture. When performing an antegrade

femoral puncture, where the accuracy of position

is very sensitive, uoroscopy can be very helpful

for orientation. Fluoroscopy is not usually required

during the actual puncture. Occasionally, when

there is blood return from the puncture needle but

the guidewire cannot be advanced, a uoroscopy

spot check of the position of the wire is warranted.

Soon aer the guidewire has been placed into

the artery aer a routine puncture, uoroscopy

should be initiated. is may be continuous or

intermittent but frequent. If there is any resistance

to guidewire advancement on the rst pass, the

operator should stop and check the wire’s progress

with uoroscopy. e guidewire may have turned

into the iliac circumex vessel or another collat-

eral route or may have encountered a lesion close

to the puncture site. Any encounters with lesions

must be observed using uoroscopy. If the opera-

tor suspects iliac occlusive disease ipsilateral to the

puncture, early initiation of uoroscopy is war-

ranted. Aer the guidewire is in place, the catheter

is observed with uoroscopy as it is passed over

the wire.

https://t.me/med1917

When to abandon an access 33

ABOUT ACCESS SHEATHS

A hemostatic sheath provides protection of the

arteriotomy from the irregular edges of endo-

vascular devices. Multiple guidewire or catheter

exchanges are made simpler and safer with a sheath

in place. A sheath reduces the friction encountered

at the access site when manipulating a selective

catheter into a branch. An access sheath has a one-

way hemostatic valve, a dilator to stien it during

placement, and a side arm port that is used for

the administration of medication or contrast. e

sheath is advanced only with the accompanying

dilator in place to avoid uncontrolled endarterec-

tomy by the hollow sheath tip. e operator must

be cognizant of the location of the tip of the sheath.

Any angiographic or balloon catheter must clear

the tip of the sheath in order to function properly.

If there is a lesion intended for treatment near the

puncture site, use a sheath with a radiopaque tip

so that the tip of the sheath is easily identied.

Sheaths are sized according to the largest diameter

catheter the sheath will accept (see “Basic sizing

issues”). Aer the sheath is placed, the seal of the

hemostatic valve can be opened for guidewire

insertion by placing the tip of the dilator through

the valve.

Technique: Handling access sheaths

1. Flush and wipe the sheath and its dilator with

heparinized saline.

2. Turn stopcock on side arm to “o” position.

3. Double-check sheath size before insertion.

4. Lock or snug-t the dilator into the hub of the

sheath.

5. Enlarge the skin entry site.

6. Use arterial dilators to prepare the tract.

7. Hold pressure at entry site during exchanges.

8. Pin the guidewire.

9. Insert sheath by holding along its sha, usu-

ally close to the tip of the sheath.

10. Rotate sheath slightly to pass through the

subcutaneous tissue.

11. Hold pressure at arteriotomy until the tip of

the sheath is in the artery.

12. Orient the side arm toward the operator.

13. Monitor the sheath’s dilator to make certain it

does not back out.

14. If there is catching or hesitation, check the

sheath tip is smooth.

15. If there is resistance in the artery, stop and

evaluate. Make sure the tip of the sheath is

smooth.

16. Advance sheath to its hub.

17. Aer placement, remove dilator, aspirate, and

ush.

18. Upsize the sheath if there is bleeding around it.

19. Do not advance the sheath without the dilator

in place.

20. Replace the sheath if tip is damaged or irregular.

21. Secure the sheath with a stitch if it tends to

slide out (not usually necessary).

22. Do not inject through the side arm if the

sheath is lled with an equally sized catheter.

HOW DO YOU DECIDE WHEN TO

PLACE A LARGER ACCESS SHEATH?

A common scenario is that the case begins with

the smallest adequate access for angiography.

When the decision is made to proceed to interven-

tion, the operator selects a new sheath and upsizes

to the caliber needed for the interventional devices

required. However, occasionally there is substan-

tial bleeding around the sheath, especially with

heavily calcied arteries. is may also be mani-

fested by a gathering hematoma at the access site.

In this case, it is best to upsize the sheath by one

French size to tamponade the hole. It also helps to

hold pressure at the access site for a few minutes,

even while the sheath is in place. Another scenario

where a sheath upsize may be required is if there is

signicant tortuosity in the iliac artery that can-

not be managed with the sheath selected or that

may be continuously pushing the sheath out of the

access site. In this case a larger and longer sheath

can be placed through the same site. It must be

two French sizes larger. e original sheath can

then be placed through it. For example, if a 6-Fr

sheath is needed for treatment, but it is not han-

dling well because of severe tortuosity, an 8-Fr

sheath can be placed and then the 6-Fr sheath

is placed through it (sheath-within-a-sheath).

is has the eect of allowing the 6-Fr sheath a

straighter path and with less friction.

WHEN TO ABANDON AN ACCESS

Abandoning an access is also discussed in

Chapter2. e key factor is to recognize as soon

as possible during the procedure that an access

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