Добавил:
Sekretar
kiopkiopkiop18@yandex.ru
t.me/Prokururor I Вовсе не секретарь, но почту проверяю
Опубликованный материал нарушает ваши авторские права? Сообщите нам.
Вуз:
Предмет:
Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_3924_Библиотеки_им_академика_М_И_Перельмана
.pdf
214 More about balloon angioplasty: Keeping out of trouble
proximally or distally, during an attempt to dilate
(Figure 18.8). is occurs more commonly during
dilation of intimal hyperplasia or an anastomotic
stenosis. Balloon herniation is observed using uo-
roscopy. e balloon seems to pop out of the lesion
just before it reaches its full, rounded prole. To
minimize the likelihood of herniation, place the
center of the balloon just beyond the center of the
lesion, partially inate the balloon to secure it, and
then hold traction on the catheter sha as ina-
tion is completed. e balloon is held in place even
though it tries to pop forward. Another option
to prevent herniation is to use a longer balloon.
A modied balloon, such as a scoring or cutting
balloon, may also be useful in this situation.
Dilating a lesion that is located adjacent to a
large ulcer or an aneurysmal segment may be con-
traindicated because of the increased risk of embo-
lization or rupture. If angioplasty is required in
this setting, consider covering the entire segment
with a covered stent.
Dilation with a large (more than 10-mm diam-
eter) or compliant balloon, or one with a small
caliber ination port, is sometimes followed by
A
B
C
Fig. 18.6 Options for proceeding when working room is limited. (A) In this example, working room
between a common femoral access site and either iliac lesion is not adequate. A proximal approach
through the radial or brachial artery is an option. In this case it is suboptimal because it must be
performed across an aortic aneurysm, which increases the risk of embolization. (B) Another option is
to proceed with femoral access but to have the sheath only a few centimeters into the artery. If this
option is chosen, the sheath must be secured so that it does not pop out of the artery at an inoppor-
tune time. One way to do this is to have an assistant manually secure the sheath. (C) Another option
is to create more working room by placing the sheath in the proximal SFA, either percutaneously or
through a cutdown. This can be done safely using ultrasound guidance. If the artery in this location
has a minimum 5-mm diameter, a closure device can also be considered.
https://t.me/med1917
Technique: Solving angioplasty problems 215
very slow emptying of contrast from the balloon.
e balloon port should be aspirated with a large
empty syringe (20 mL or larger) for a few seconds
and the catheter and hub icked with the nger
to disrupt and mobilize any air bubbles. If the air
lock remains constant, high negative pressure is
applied by withdrawing the plunger on the syringe
and locking it in place with the plunger fully
withdrawn and the syringe forming a vacuum. If
negative pressure must be maintained during bal-
loon catheter removal, a two-way stopcock may be
placed on the syringe and closed with the syringe
on full aspiration so that there is constant negative
pressure (Figure 18.9). ese maneuvers maintain
a vacuum by preventing the plunger from sliding
back into the body of the syringe.
TECHNIQUE: SOLVING
ANGIOPLASTY PROBLEMS
1. Balloon catheter will not track along the guide-
wire. Exchange for a stier guidewire and/or
insert a long sheath (see Chapter 7, Fi g ure 7. 6).
2. Balloon will not advance through a lesion.
Place a 5-Fr catheter over the wire to dotter
the lesion. at oen works, but if it does not,
exchange for a lower caliber wire (0.014- or
0.018 inch) and predilate with a low-prole
balloon catheter.
3. Balloon is unable to dilate residual atheroscle-
rotic waist (Figure 18.5).
4. Balloon ruptures on calcied lesion. Use
a thicker polymer balloon, dilate calcied
A
B C
D E
Fig. 18.7 Management when a balloon ruptures on a calcified plaque. (A) A guidewire is placed
across a common iliac artery stenosis. (B) The appropriately sized balloon is advanced into position
but ruptures during inflation. Using fluoroscopy, contrast is seen extravasating from the balloon.
Aspiration of the balloon port of the angioplasty catheter reveals bloody return fluid. (C) A more
puncture-resistant, polymer balloon is used to dilate the lesion, which may require a larger sheath to
accommodate the shaft size. These are usually classified as “high-pressure” balloons. (D) The lesion
can also be dilated incrementally using the shoulder of the balloon, avoiding the sharpest part of
the lesion until last. (E) A stent can also be placed across the lesion, using either a self-expanding, a
balloon-expandable, or a covered stent and then dilating the calcified lesion after stent placement.
The newly placed stent typically protects the balloon. If this option is selected, enough lumen must
be gained to permit crossing of the stent delivery catheter.
https://t.me/med1917
216 More about balloon angioplasty: Keeping out of trouble
A
B
C
D
E
Fig. 18.8 Management when a balloon herniates
past the lesion during inflation. (A) A guidewire is
passed through a stenosis. (B) As the balloon takes
its shape, it begins to migrate out of the lesion. This
is common with intimal hyperplastic lesions that are
short but circumferential and usually recalcitrant to
standard angioplasty. (C)The expanded balloon
pops out of the angioplasty site. (D) The balloon
catheter is deflated and advanced so that one radi-
opaque marker is beyond the lesion. The balloon is
reinflated while traction is applied to the catheter.
As the balloon attempts to pop out of the lesion, it
is held in place with manual traction. (E) The bal-
loon catheter can also be exchanged for one with a
longer balloon.
A
B
C
Fig. 18.9 Management
when a balloon will not
empty or empties slowly.
Do not move the bal-
loon until the inflation
fluid has been removed.
(A) Aspiration of a large
balloon may produce
very slow emptying. This
may also occur with low-
profile balloons when the
inflation port is small in
caliber. (B) A large empty
syringe generates more
negative pressure. It is
used to aspirate the bal-
loon. (C) Continuous aspi-
ration can be achieved
by drawing the plunger
back to the rubber seal of
the syringe and locking it
in place. This can stay in
place while the balloon is
being withdrawn.
https://t.me/med1917
Management of arterial rupture 217
portion with the shoulder of the balloon, or
place a stent and dilate (Figure 18.7).
5. Balloon herniates past lesion during ination.
Apply traction to the catheter during ination
or use a longer balloon (Figure 18.8).
6. Balloon will not empty aer ination (air lock).
Apply continuous negative pressure with a
large (20 mL or larger) syringe (Figure 18.9).
7. Balloon cannot be withdrawn into sheath.
Rotate to fold wings and aspirate while apply-
ing steady traction.
MANAGEMENT OF ARTERIAL
RUPTURE
Acute, sharp, or unremitting pain may indi-
cate arterial rupture, and immediate arteriogra-
phy should be performed. If arterial rupture has
occurred, the best maneuver is to advance the
balloon back into the location of the rupture site
and inate it to prevent leakage from the artery
(Figure 18.10). is tamponades bleeding until
emergency repair can be performed with either
open surgery or a covered stent. If the patient is
systemically anticoagulated, consider reversal.
If the patient is heavily sedated, however, or if
the procedure is being performed concomitantly
with another operation and the patient is under
anesthesia, pain may not serve as a warning sign.
Following angioplasty, several minutes may pass
before completion arteriography is performed.
Sudden hemodynamic instability in this set-
ting should be considered a rupture until proved
otherwise.
Any extravasation of contrast or vessel wall
staining on completion arteriography is signicant.
Visualization of contrast extravasating through
the arterial defect means that a high-ow rupture
has occurred and that shock is only moments away.
Contrast that has leaked beyond the connes of the
vessel wall but appears to be stable may represent a
contained rupture. A rupture aer balloon angio-
plasty should not be stented because the stent is
likely to reopen the incidental arteriotomy. is
situation must be carefully distinguished from an
acute local dissection, which is much more com-
mon and for which a stent is oen indicated. Aer
the balloon is reinated, some time is usually pro-
vided to make a plan. e best way to manage a
rupture from an endovascular standpoint is with
an appropriately sized covered stent or stent–gra.
Even if it is not an ideal location for a covered stent,
this can also be done to save an urgent situation
and then redone electively at a later time if needed.
e appropriate sheath and wire size for a covered
stent must be placed if not already in place. is
means that balloon occlusion will have to be relin-
quished in order to make this exchange. Inating
the balloon for several minutes may stop the active
leak. If the rupture site is in an iliac artery, con-
sider contralateral access in order to place a more
proximal occlusion balloon.
If there is staining or a slight blush of contrast
outside the wall of the artery, and the patient
remains stable, the operator may decide to observe
the patient rather than place a covered stent. is
is an acceptable approach but with caveats. Wait
for a period of time on the table while the patient
is stable and then obtain a repeat arteriogram.
If the blush outside the artery wall persists, or if
anything else happens (e.g., patient has pain, insta-
bility), then go ahead and place a covered stent to
prevent further hemorrhage.
Iliac rupture that occurs during endovascular
aortic aneurysm repair, thoracic aortic aneurysm
repair, or transcatheter aortic valve placement
A
B
Fig. 18.10 Management of arte-
rial rupture at the angioplasty site.
(A)A rupture occurs at the interface
between hard calcified plaque and
the adjacent soft artery after angio-
plast y. (B) The angioplasty bal-
loon is reinserted and reinflated to
tamponade the bleeding site. This
gives the operator time to prepare a
covered stent to place at the site of
perforation.
https://t.me/med1917
218 More about balloon angioplasty: Keeping out of trouble
may be related to relatively larger delivery sheaths.
In this setting, the problem is usually manifested
by hemodynamic instability. Usually, bilateral
femoral access has already been achieved. e side
contralateral to the rupture can be used to rapidly
establish an occlusion balloon at the aortic bifur-
cation. is usually requires a 12-Fr sheath. Also
in this setting, on the side of the rupture there
is usually already a sheath large enough to place
any stent–gra that may be required to cover the
defect in the arterial wall. Sometimes, what hap-
pens is that the rip takes place during initial pas-
sage of the sheath, but the sheath is large enough
that it tamponades the defect and it is not possible
to recognize the defect. Later, when the sheath
is withdrawn, the patient may become unstable.
Either way, aer passage of a large sheath, or
passage of a sheath that is close to the size of the
access artery, perform retrograde iliac arteriogra-
phy aer sheath withdrawal to examine the integ-
rity of the artery.
Rupture of the SFA, popliteal artery, or tibial
artery is much less likely to cause life-threatening
hemorrhage and more oen results in acute occlu-
sion. Some localized ruptures heal or form chronic
pseudoaneurysms. If a rupture occurs in the
infrainguinal arteries, wait several minutes and
obtain a repeat arteriogram. If the artery remains
patent and the extramural hematoma is not
expanding, surgery may not be required. e most
common scenario is that the surrounding tissues
help to contain the rupture. It is also not unusual
for an SFA angioplasty to rupture into the super-
cial femoral vein. ese are usually self-limiting
and rarely require treatment. A covered stent or
stent–gra should be considered if there is contin-
ued bleeding, an expanding hematoma, or a high-
ow arteriovenous stula. Occasionally, rupture
of an infrainguinal artery results in compartment
syndrome and the clinician must have this in mind
as a possibility. e solution for compartment syn-
drome is fasciotomy. Although rarely required, the
consequences are severe if not treated.
e most common cause of postangioplasty
arterial rupture is overdilation. Rupture is rare if
simple guidelines are followed:
●
Carefully consider the diameter of the chosen
balloon prior to usage.
●
Be certain that the balloon does not extend
into a more distal tapering artery.
●
Double-check that the correct balloon is being
advanced, especially if multiple dierent-sized
catheters have been opened for the case.
●
Accept a decent result; do not be greedy about
obtaining a cosmetically perfect completion
image.
●
Know when to quit (or when to convert to
surgery) if the limit of endovascular capability
has been reached.
Conditions treated with balloon angioplasty are
rarely, if ever, life threatening but arterial rup-
ture is one complication that may result in death.
Ruptured arterial segments should not be treated
with stents, but covered stents may obviate the
need for emergency surgery.
MANAGEMENT OF EMBOLIZATION
In general, prior to balloon angioplasty, it is best to
evaluate t he runo ser ved by the artery to be treated
and have a sense for its quality. is is helpful later
if there is any question about whether emboliza-
tion occurred. If the patient has a lesion that has
previously embolized or looks like it might, use a
distal protection device, extra anticoagulation, and
vasodilators and consider primary coverage with a
stent or a stent–gra. If there is already suspicion
that there is thrombus present in the lesion, some
clinicians advocate thrombolysis prior to denitive
treatment of the target lesion. Clinically signicant
postangioplasty embolization is unusual but may
result in organ or limb loss. In some angioplasty
cases, the patient starts o with one problem (the
lesion) and ends up with two problems (a partially
treated, possibly unstable, upstream lesion and an
ischemic or occluded outow bed). Embolization
may present as lling defects at some location dis-
tal to the angioplasty site, lack of ow in the run-
o arteries, very slow ow, or as pain experienced
by the patient in the outow vascular bed. If this
occurs, the following steps should be taken:
1. Administer a fully anticoagulating dose of
heparin. Check the activated clotting time and
extend to >250 seconds.
2. Maintain any guidewire that is in the distal
aected vascular bed.
3. Inspect sheaths that are already in place.
Aspirate and ush.
4. Administer vasodilators.
https://t.me/med1917
Technical aspects of balloon angioplasty in different vascular beds 219
5. Consider the cause. Is the embolus from the
angioplasty site or the access site, or is it due
to thrombus formation from low ow? e
usual cause is embolization from an upstream
treatment site.
6. Stabilize the angioplasty site as soon as pos-
sible. is usually means stent placement.
7. Place a multiple side hole catheter distally into
the aected outow bed and perform local
arteriography. Administer tissue plasminogen
activator; several milligrams can be adminis-
tered as a pulse spray over 10 minutes.
8. Use an aspiration catheter, such as an Export
®
AP Aspiration Catheter or a Pronto
®
LP
Extraction Catheter, and aspirate the runo
bed as much as possible.
9. Repeat the arteriography.
10. If lling defects continue, continue tissue
plasminogen activator at 1 mg/hour.
11. Use mechanical thrombolysis with laser or an
AngioJet™ Peripheral rombectomy System
or aspiration thrombectomy with a Penumbra
Aspiration Device.
MANAGEMENT OF ACUTE
OCCLUSION
An acute occlusion at the angioplasty site that
occurs immediately aer balloon angioplasty and
is apparent on a completion arteriogram is usually
caused by dissection (Fig ures 18.11 and 18.12).
A stent is placed at the same site where the bal-
loon angioplasty was performed to force back in
place the dissection ap that has been elevated and
propagated from the angioplasty site. Aer place-
ment of a single stent, arteriography usually dem-
onstrates patency. If necessary, additional stents
are placed distally and proximally to the rst stent
until patency is achieved.
TECHNICAL ASPECTS OF BALLOON
ANGIOPLASTY IN DIFFERENT
VASCULAR BEDS
Considerations of balloon angioplasty vary from
one vascular bed to another (Table 18.2). Carotid
bifurcation lesions are typically focal and it is usu-
ally possible to achieve full balloon expansion.
One possible exception to this is when a circum-
ferentially calcied lesion is present. One possible
mechanism of stroke with carotid angioplasty is
release of particulate with overaggressive balloon
dilation. Carotid angioplasty is followed by carotid
stent placement. e angioplasty experience with
lesions of the great vessels varies signicantly based
on lesion location. Lesions at the origin of the
innominate artery, le common carotid artery or
le subclavian artery tend to be spillover of highly
calcied plaque from the aortic arch. Because this
is calcied and is spillover, it is frequently circum-
ferential, which is recalcitrant to dilation. Balloon-
expandable stents are usually placed in these
positions. Stents should be avoided in the axillary
A
B
C
D
E
Fig. 18.11 Management of acute occlusion at
the angioplasty site. The most common cause of
acute occlusion after angioplasty is dissection.
(A) A dissection flap is raised at the angioplasty
site that is occluding flow. (B) A catheter is
passed over the guidewire and limited arteriog-
raphy is performed. This attempt to do proxi-
mal arteriography is optional. If the operator
believes that some other factor is at play, such
as thrombosis, an arteriogram is helpful. Ifthe
overwhelming likelihood is occlusion due to
severe dissection, proceeding to stent place-
ment is probably most expeditious. (C) A stent
delivery catheter is passed, in this case carrying
a balloon-expandable stent, through the sheath
and across the original angioplasty site. (D) The
balloon is inflated to deploy the stent at the site
of the dissection. (E) The dissection flap opened
and secured by the stent.
https://t.me/med1917
220 More about balloon angioplasty: Keeping out of trouble
and brachial arteries. Lesions in these locations that
are clinically signicant are unusual and may be
due to thoracic outlet syndrome in the case of the
axillary artery or to humerus injuries in the case of
the brachial artery. Balloon angioplasty of the aorta
can release a tremendous amount of debris. Avoid
this if there is evidence of ectasia and denitely do
not perform angioplasty of an aneurysm. Sizing
for the infrarenal aorta can also be dicult, since
many patients who develop clinically signicant
occlusive disease of the infrarenal aorta also have
small arteries. Careful consideration must be taken
of the inferior mesenteric artery and whether or
not it is a signicant supply to the le colon. Renal
and visceral angioplasty likewise frequently do not
result in signicant lumen gain since it is usually
plaque that has spilled over from the aorta and
is heavily calcied. ese arteries almost always
A
B C
Fig. 18.12 Stent placement after dissection. (A) Balloon angioplasty of a focal, common iliac artery
lesion causes a dissection. (B) The dissection is identified by the appearance of contrast retained in
the arterial wall, flow streaming effects through the lumen, and extension of abnormality well beyond
the original lesion. Guidewire access is carefully maintained. (C) Stent placement at the original angio-
plasty site usually closes the false channels.
Table 18.2 Technical aspects of angioplasty in different vascular beds
Easily
dilated
Need a
stent
Causes
spasm
Embolization
risk Comments
Carotid Ye s Always Frequent High
Great vessel
origin
No Always No Moderate Arch dissection is a risk
Subclavian Usually Usually Occasional Low Visualize vertebral origin
Axillary Yes Usually not Frequent Low Not a good place for a
stent
Brachial Yes No Frequent Low
Aorta Usually Usually No Moderate
Renal Usually Ye s Occasional Low
Visceral No Yes Rare Moderate to
nominal
Stent frequently will not
expand
Iliac Yes* Usually Rare Low
SFA–popliteal Yes* Often Rare Low
Tibial Ye s Occasionally Occasionally Low
Pedal Often not No Often No
Abbreviation: SFA, superficial femoral artery.
* unless heavily calcified.
https://t.me/med1917
Assessing the acute results of balloon angioplasty 221
undergo stent placement. Angioplasty of the iliac
artery can result in rupture. Availability of covered
stents is helpful. Iliac angioplasty that causes pain
is typically at the limit of the artery’s expansion.
If pain does not resolve on deating the balloon,
this could be a sign of injury with leakage into the
retroperitoneum. e supercial femoral and pop-
liteal arteries oen contain very long lesions. It is
helpful to use a balloon that covers as much of the
lesion as possible in a single ination. A long slow
ination, a 1.1 to 1 ratio of balloon to artery diam-
eter, and a prolonged ination are all helpful for
achieving lumen gain. In the tibial vessels the size
of the artery is commonly underestimated due to
the diuse narrowing of the lumen, even on what
appears to be a widely patent artery. Pedal angio-
plasty is performed with some regularity but is not
yet proven in terms of its patency and how best it
should be done.
ASSESSING THE ACUTE RESULTS
OF BALLOON ANGIOPLASTY
Completion angiography
A completion angiogram should be obtained on
every case. Typically, access across the lesion is
maintained until this exercise has been completed.
It should be performed and compared with the pre-
treatment angiogram. Any evidence of a technical
defect should be treated. If it is unclear whether
the results show lack of technical defect, one might
consider other views.
When to include oblique views
Oblique views may be obtained of almost any ves-
sel, but are usually not necessary in a routine case.
In high-stakes situations, such as carotid stenting
or long segment drug-coated balloon angioplasty
in the lower extremity, oblique views are common.
Dierent views of the foot (usually AP and lateral)
are usually helpful in below-the-knee cases, and
especially if pedal angioplasty is being considered.
When to include runoff
Understanding runo from the target vessel
treatment site is always helpful, oen necessary,
and frequently neglected. If there is renal insuf-
ciency and limitations on contrast, this is one
area in which compromise can be considered.
Any patient being treated for tissue loss, man-
agement of an occlusion, or long segment disease
should have runo evaluated before and aer
treatment.
Measure pressure
Pressure may be measured across a lesion if it helps
to clarify a specic plan. A pressure wire can be
passed across the lesion and this allows measure-
ment even in small caliber vessels. Pressure distal
to the lesion is measured using a pressure wire
or a catheter and is compared with the pressure
measured at the sheath tip, which is proximal to
the lesion. Alternatively, a pull back pressure can
be assessed by pulling back a pressure wire or a
pressure measuring catheter across the lesion. e
threshold for a signicant pressure gradient is typi-
cally considered to be around 10 mmHg systolic.
Pressure uctuations during the procedure may
hamper the ability to clearly measure the pressure
gradient.
Intravascular ultrasound
is involves an ultrasound transducer mounted
on the tip of a catheter. IVUS can be used to assess
the results of angioplasty. IVUS is used to obtain
a cross-sectional view and measure the degree of
residual stenosis or assess the severity of dissec-
tions. ese sections in particular may cause ow
limitation without this being visible on an arterio-
gram. If a large amount of tissue is protruding into
the lumen, it should be treated to prevent acute
occlusion and/or later restenosis.
Intraoperative duplex ultrasound
May be used by externally evaluating the vessel
with a sterile ultrasound probe. Intraoperative
duplex ultrasound is particularly helpful aer open
surgery such as carotid or femoral endarterectomy,
femoral-to-popliteal bypass, or femoral-to-tibial
bypass. It can also be used following long segment
SFA stenting by transcutaneous evaluation of the
artery during the operative procedure.
https://t.me/med1917
https://t.me/med1917
223
19
Stents, covered stents, stent–grafts
IMPACT OF STENTS
Vascular stents have made it possible to reline a
diseased artery. Stents have had a major impact on
the development of endovascular surgery, which is
manifested in four ways:
1. e complications of balloon angioplasty, such
as dissection and residual stenosis, may be
immediately treated.
2. Lesions that otherwise would have required
open surgery, such as occlusions, long lesions,
or recurrent stenoses, may be treated with
endovascular surgery. is is particularly
appropriate when it provides an additional
option for the treatment of patients who are at
high risk for open surgery.
3. e overall spectrum of arterial lesions that
can be approached with endovascular tech-
niques has broadened dramatically. Whether
or not a particular lesion ultimately requires
stent placement, the availability of stents has
permanently altered the general approach and
the consideration of options.
4. Combining stents with gra material to create
covered stents or stent–gras has permitted the
endovascular treatment of aneurysmal disease
or exclusion of disease that requires treatment
due to its complexity.
Each stent application has its own cost and
complication risks. e sheath must usually be
upsized, a foreign body is implanted, and stents
have their own unique complications. Stents in
some locations, such as the lower extremity or the
renal artery, seem to be particularly susceptible to
recurrent stenosis. e cost of each stent increases
the overall cost of an endovascular intervention.
eplacing of stents may be motivated by the wish
to extend the short- or long-term success of balloon
angioplasty, to avoid surgery, or to avoid repeat bal-
loon angioplasty, but this should be considered in
each case. Stents have improved to the point where
they can be easily and smoothly incorporated into
a procedure, even if a stent was not necessarily
intended from the start of the case. Drug-eluting
stents have the potential, once fully developed, to
decrease or prevent intimal hyperplasia.
STENT CHOICES
Stents are either balloon-expandable or self-
expanding (Figure 19.1). e main characteristics
of these two types of stents are listed in Table 19.1.
e Palmaz
™
Stent was the original balloon-
expandable stent design. Numerous dierent
designs for balloon-expandable stents are avail-
able currently. e Palmaz
™
Stent is a straight,
metal, relatively rigid, and balloon-expandable
cylinder. Balloon-expandable stents have a high
level of resistive force or crush resistance, but
once the stent is implanted it exerts no chronic
outward force because it is xed. e stent is pre-
crimped onto a standard angioplasty balloon and
is deployed when the balloon is inated. Initially,
the stent had to be hand crimped onto the balloon
catheter. Now the stents are premounted on the
balloon catheters when ordered. e rigid balloon-
expandable stent has excellent hoop strength but
can be crimped by external forces. ese stents
perform best when placed in locations that have
limited mobility, such as the aortic bifurcation.
Balloon-expandable stents perform best when they
are relatively short in length, since they are rigid.
ese stents also shorten slightly as they expand
in diameter. Most renal artery stents are less than
https://t.me/med1917
Соседние файлы в папке Библиотека им академика М.И. Перельмана