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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_3597_Библиотеки_им_академика_М_И_Перельмана
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Peripheral Arterial Disease and Angiography
Figure 5-4 Right superficial femoral artery (SFA) with significant serial
stenosis.
managing particular femoropopliteal lesions, but no randomized comparative data exist that demonstrate improved outcomes compared
with conventional balloon angioplasty and stenting.
Atherectomy removes obstructive plaque and can be used in
conjunction with angioplasty and stenting or as a stand-alone technique (Figs. 5-4 and 5-6). Atherectomy devices can be divided into
either excisional (removal of plaque) or ablative (disintegration or
fragmentation of plaque). These devices provide the opportunity to
reduce plaque volume, which may provide advantages in traditional
“no-stent” zones (common femoral and popliteal artery) (Figs. 5-7 and
5-8), in lesions with bulky plaque (optimization of stent and/or balloon
expansion), and in complex lesions involving the bifurcation of vessels
where plaque prolapse may compromise flow to an adjacent segment.
Technical Considerations
Selection of arterial access site (Table 5-5) for endovascular treatment
of the femoropopliteal segment depends on lesion location, presence
of concomitant iliac or infrapopliteal disease, patient-specific variables, and operator proficiency. Most often, the preferred approach is
retrograde access from the contralateral CFA, with advancement of a
sheath over the iliac bifurcation. This strategy permits treatment of
iliac artery disease and allows familiar access techniques to be used.
The crossover approach may be hampered by inadequate length of
interventional equipment if treatment of the infrapopliteal distribution is required, as well as attenuation of one-to-one torque in cases
with acute angulation of the iliac bifurcation. In the absence of iliac
and CFA disease, for patients in whom infrapopliteal or distal
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Figure 5-5 Atherectomy of superficial femoral ar tery (SFA) plaque (some
is caught in the distal protection device/basket).
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Peripheral Arterial Disease and Angiography 253
Figure 5- 6 Postatherectomy angiogram of right superficial femoral artery
(SFA).
femoropopliteal disease is the target, an antegrade common femoral
approach may be beneficial. “Straight-line” access and proximity of
the access platform to lesion substrate improves wire torque and catheter manipulation. The benefits of antegrade access are attenuated by
a higher risk of bleeding and the relatively greater degree of difficulty
compared with retrograde femoral access. In cases of complex occlusion with bridging collaterals or in lesions recalcitrant to antegrade
recanalization, retrograde access via the popliteal or pedal arteries
may be considered. Transradial access is gaining popularity for iliac
interventions; presently, however, in most patients, catheter lengths of
135 or 150 cm do not have adequate reach to treat diseased segments
beyond the proximal or mid-superficial femoral artery.
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Peripheral Arterial Disease and Angiography
Figure 5-7 Popliteal ar tery stenosis.
Figure 5-8 Postangioplasty angiogram of popliteal artery.
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Table 5 -5
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Peripheral Arterial Disease and Angiography 255
Arterial Access for Different Vascular Territories
Vascular Access Target Vessel(s) to Revascularize
Retrograde CFA Aor tic arch vessels, renal, and mesenteric
Contralateral CFA Contralateral iliacs, CFA, PFA, SFA, and
Antegrade CFA Mid to distal femoral, popliteal, and
Brachial/radial arter y Renal (caudal takeoff ), mesenteric, and
Retrograde popliteal ar tery SFA and iliac artery
Retrograde pedal Infrapopiteal, popliteal, SFA
CFA, Common femor al ar tery; PFA, prof unda femoral ar tery; SFA, super ficial femor al
artery.
arteries
popliteal ar teries
infrapopliteal
iliac arteries
Angiographic Technique
As in other vascular distributions, the use of DSA, a large flat-panel
detector plate, and appropriate collimation optimizes image quality
and reduces radiation exposure. The bifurcation of superficial and
profunda femoris arteries is best visualized in 45-degree ipsilateral
oblique angulation. Sometimes contralateral oblique imaging is
helpful when imaging a suspected ostial SFA occlusion. The main
course of the femoropopliteal artery is best imaged in a straight anteroposterior (AP) projection, or perhaps 15 to 30 degrees of ipsilateral
oblique, in order to display the infrapopliteal trifurcation. Imaging of
eccentric lesions may require tailored angulations. Baseline and postintervention runoff angiography is recommended in order to exclude
iatrogenic DE.
Femoropopliteal interventions are most often performed with
UFH because it may be rapidly reversed if necessary. The optimal
target activated clotting time (ACT) is between 250 and 300 seconds.
Bivalirudin has been used with increasing frequency in endovascular interventions, but it is more expensive and not immediately
reversible.
The particular technique used to cross a femoropopliteal stenosis
depends on lesion, patient, and operator-specific parameters. Support
catheters are commonly used in conjunction with 0.035-, 0.018-, or
0.014-inch guidewires. CTOs pose a unique challenge and may be
addressed with a variety of techniques. In some lesions, it may be
possible to pass a wire in an antegrade fashion through the occlusion
from true lumen to true lumen; in other cases, a subintimal approach
may be required, advancing a prolapsed or “knuckled” wire in the
subintimal plane parallel to the reconstituted lumen and then reentering the true lumen using an angled wire or a dedicated CTO reentry
device. The overall success rate of crossing even complex lesions
(TASC C and D) is approximately 85% to 95% among experienced
operators.
Complications of Femoropopliteal
Endovascular Interventions
Because DE may occur during interventional procedures, many advocate the use of distal embolic protection strategies in cases with only
one-vessel infrapopliteal runoff, particularly in the context of CLI. If
DE is obser ved, treatment options may include mechanical or rheolytic thrombectomy, balloon inflation, stent placement, and occasionally surgical embolectomy. Evaluate the possibility of DE before and
after every femoropopliteal intervention with comprehensive runoff
angiography.
During balloon inflations, stent placement, or atherectomy, the
creation of AV fistulae is not uncommon. Large AV fistulae can be
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treated with nitinol self-expanding stents that direct blood flow straight
to the foot, permitting most of these fistulae to heal on their own. They
can also be treated with placement of a PTFE stent graft (Viabahn
stent).
lead to compartment syndrome if not treated quickly. Most wire perforations can be managed conservatively, whereas larger perforations
must be immediately treated with balloon tamponade. Prolonged
balloon inflations (5 to 10 minutes) with or without reversal of heparin
can seal most perforations. If this fails, consider placement of a PTFE
stent graft (Viabahn stent) with possible surgical referral. Overall, most
such complications can be treated percutaneously.
Peripheral Arterial Disease and Angiography
Vessel perforation or rupture is a feared complication and can
Infrapopliteal Interventions
Disease involving the infrapopliteal vessels may be highly variable in
its anatomic features, response to conventional endovascular techniques, and clinical importance to the patient. In addition, advanced
stages of the disease, including CLI, have been managed historically
by surgery. Significant controversy remains regarding the optimal management of patients with infrapopliteal disease. The term infrapopliteal
refers to vessels that include the anterior tibial (AT); tibioperoneal
trunk; PTA; peroneal, medial, and lateral plantars; and metatarsal arch
arteries. These vessels are relatively small in caliber and are often
diffusely diseased or occluded. These anatomic features render
them recalcitrant to endovascular techniques, but technology breakthroughs have improved outcomes. Such breakthroughs include the
development of improved guidewire technology that permits crossing
of long CTOs; long, low-profile angioplasty balloons that minimize the
development of luminal disruption or dissection even when treating
very long CTOs; increased operator familiarity and dexterity with
transpedal access and “retrograde wire” techniques to cross CTO segments where antegrade crossing was unsuccessful; and the future
promise of drug-eluting therapies to reduce restenosis following successful endovascular treatment.
In contrast to patients with iliac and femoropopliteal disease,
for whom the majority of endovascular treatments are performed
to relieve claudication, those with infrapopliteal disease typically
undergo revascularization only for advanced clinical stages of disease,
such as CLI. Such patients often present with rest pain and/or tissue
breakdown and ulceration (Rutherford IV to VI) due to arterial insufficiency. The technical and therapeutic goal in patients with CLI due
to infrapopliteal disease is to reestablish “straight-line” pulsatile blood
flow to the foot (see Fig. 5-3), specifically the region of the foot
supplied by one particular infrapopliteal vessel. It has been demonstrated that restoring perfusion to the affected angiosome (Fig. 5-9) is
more effective than restoration of indirect flow through a different
infrapopliteal vessel that does not directly perfuse the ulcerated
territory.
Although endovascular treatment of infrapopliteal disease has
high rates of restenosis, the temporary reestablishment of pulsatile
flow to the foot is often sufficient to promote wound healing. Even if
restenosis of the treated segments occurs, the impact of wound healing
and limb salvage may remain durable. As a result, this treatment paradigm for CLI has evolved: Reestablish “straight-line flow” to the foot
(even if long-term patency is limited), because this may have profound
impact on wound healing and limb salvage.
Technical Considerations
In many ways, the technical approach to infrapopliteal disease mirrors
strategies perfected in the coronary distribution with arteries of similar
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Peripheral Arterial Disease and Angiography 257
Medial
plantar
Anterior
tibial
Calcaneal
branch
of PTA
ATA angiosome PTA angiosome PA angiosome
Figure 5 -9 Angiosome concept. Six angiosomes of the foot and ankle are
supplied by three main arteries. Left, The anterior tibial artery (ATA) becomes
the dorsalis pedis ar tery that supplies the dorsum of the foot and dorsum
side of the toes. Middle, Three main branches of the posterior tibial artery
(PTA) supply distinct por tions of the sole: the calcaneal branch to the heel,
the medial plantar artery to the medial, and the lateral plantar ar tery to the
lateral midfoot and the forefoot. The PTA supplies the plantar side of the
toes, the web spaces between the toes, the sole of the foot, and the inside
of the heel. Right, The peroneal artery (PA) supplies the lateral border of the
ankle and the outside of the heel. (Iida O, Soga Y, Hirano K, et al: Long-term
results of direct and indirect endovascular revascularization based on the
angiosome concept in patients with critical limb ischemia presenting with
isolated below -the -knee lesions. J Vasc Surg 55[2]:363–370, 2012.)
Lateral
plantar
Peroneal
Calcaneal
branch
of PA
caliber. The majority of interventions is performed using 0.014-inch
wires, low-profile angioplasty balloons, occasional use of atherectomy
techniques, and—in rare cases of highly recalcitrant stenosis or flowlimiting dissection—coronary stent systems, including drug-eluting
stents.
In cases of pure infrapopliteal disease, antegrade arterial access
from the ipsilateral CFA may provide the most effective platform for
intervention. Delivery of a long sheath to the distal popliteal artery
may limit contrast use and permits excellent wire torque and catheter
handling through these complex segments. Ipsilateral retrograde, or
transpedal, access is gaining popularity, because it provides opportunity to address lesions where the proximal cap of a CTO may not
readily be traversed in an antegrade fashion. Take care when accessing the dorsalis pedis or PTAs, however, because disruption of these
vessels may compromise the only remaining “outflow” to the foot.
Although beyond the scope of this chapter, pedal access is often
obtained using smaller needle/wire systems (e.g., micropuncture) and
mimics radial access. When used in conjunction with an antegrade
femoral sheath, a small caliber wire is advanced—often through a
microcatheter system—from the transpedal access site and is then
snared and externalized from the femoral access point, permitting the
rest of the intervention to be performed in antegrade fashion. At
the conclusion of the procedure, the microcatheter is removed from
the transpedal access site with manual compression, taking care to
monitor pedal vessel patency.
Debulking strategies (such as atherectomy, rotational atherectomy, orbital atherectomy, laser atherotomy and cutting balloon
atherotomy) may have niche-specific application for infrapopliteal
disease. Indications may include removal of plaque from a complex
bifurcating segment to prevent tissue prolapse or compromise of an
adjacent vessel; desire to reduce likelihood of dissection in a no-stent
zone; and reduction of the burden of calcified plaque that may be
recalcitrant to conventional PTAs. Outcomes of debulking strategies
have not been compared to PTAs in rigorous randomized-controlled
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fashion. Take care to protect against DE with any intervention, especially debulking strategies that have a higher incidence of DE.
Peripheral Arterial Disease and Angiography
Acute Limb Ischemia
Rarely, patients with PAD may present with acute limb ischemia (ALI).
Cardinal manifestations of ALI are characterized by the “six Ps”: pain,
pallor, pulselesssness, paresthesia, paralysis, and poikilothermia
(coolness). ALI should be addressed with urgency, such as with that
of acute myocardial infraction, and it has been classified by presenting
symptoms (Table 5-6). ALI is the “heart attack equivalent in the leg.”
In the absence of reperfusion, permanent impairment of neurologic
and motor function may occur within 6 hours. Upon identification of
ALI, initiate heparin infusion immediately and implement plans for
urgent revascularization. ALI often results from acute arterial embolization and is often due to a cardioembolic event in the context of atrial
fibrillation, from a hypercoagulable state, or artery-to-artery embolus
from a more proximal aneurysm. Acute stent or graft thrombosis may
also lead to ALI.
Immediately consider surgical or catheter-based therapy. Invasive
angiography followed by either catheter-directed thrombolysis with
tissue-plasminogen activator or mechanical/rheolytic thrombectomy
is often performed. Technological advances now permit “pulse spray
thrombolysis,” wherein the clot is sprayed with a thrombolytic agent
that is permitted to dwell for 20 to 60 minutes, and rheolytic thrombectomy is then performed. In some centers, surgical thrombectomy
is performed as initial therapy, and if this fails, surgical bypass occurs.
Regardless of revascularization approach, all patients must be monitored postrevascularization for the development of compartment syndrome, which can result from hyperemic tissue swelling. In severe
cases, swelling—constrained within the fascial compartments of the
leg—may lead to permanent nerve injury with sensory and motor loss
if surgical fasciotomy is not performed. This underscores the need for
collaboration between specialists with endovascular skills and those
with open surgical skills for the treatment of patients with ALI.
Renal Artery Disease
Renal artery stenosis (RAS) is widely prevalent and confers a risk for
adverse events both in terms of organ-specific as well systemic vascular outcomes. The presence of RAS is commonly identified at the time
of coronary angiography. In five studies involving 2178 patients undergoing coronary angiography, concomitant renal angiography identified more than 50% RAS in 19% of the patients, 17.4% of which was
bilateral; more than 75% stenosis was identified in 4.8% of these
patients, 0.8% of which was bilateral.
Atherosclerosis represents the most common etiologic factor in
RAS. For patients identified to have severe RAS, nearly 15% will progress to total occlusion; if the RAS is bilateral, this may lead to dialysisdependent ESRD. The presence and severity of atherosclerotic disease
in the renal arteries may serve as an indicator of the severity of systemic atherosclerosis and, therefore, the overall risk of adverse cardiovascular events. A linear relationship has been identified between the
severity of RAS and mortality.
Three key categories of clinical findings may indicate the presence of RAS (Box 5-3): (1) presence of drug-resistant HTN (requiring
the administration of four antihypertensive medications including a
diuretic) or the abrupt onset, marked acceleration, or presence of
malignant HTN; (2) organ-specific manifestations including the presence of an atrophic kidney (<
(>1.5 cm), or unexplained renal failure following administration of
7 to 8 cm), discrepancy in renal sizes
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Peripheral Arterial Disease and Angiography 259
Audible
+/− audible
Table 5 -6
(Adapted from Rutherford RB, Baker JD, Ernst C, et al: Recommend ed st andards for repor ts dealing with lower extremity ischemia: revised version. J Vasc Surg 26(3):517–538, 1997.)
III Irreversible Limb loss or permanent damage Profound Profound None None
IIB Threatened: Immediate Salvageable if treated immediately More than just toes Mild to moderate Rare audible Audible
IIA Threatened: Marginal Salvageable if treated promptly Minimal to none None
I Viable No immediate limb threat None None Audible Audible
Rutherford Classification Scheme for Acute Limb Ischemia
Class Category Prognosis Sensory Loss Muscle Weakness Arterial Doppler Venous Doppler
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Peripheral Arterial Disease and Angiography
Box 5 -3 Clinical Clues to the Diagnosis of Renal Artery
Stenosis
Accelerated, resistant, or malignant HTN
Early -onset (<30 yrs) HTN or severe late-onset (>55 yrs) HTN
Development of new azotemia or worsening renal function after
administration of ACE inhibitor or ARB
Sudden unexplained pulmonary edema
Unexplained renal d ysfunc tion
Multivessel CAD
Refractory angina
Unexplained CHF
ACE, A ngiotensin- conver ting enzy me; ARB, angiotensin receptor blocker; CAD,
coronary arter y disease; CHF, congestive hear t failure; HTN, hy pertension.
Table 5 -7
Screening Tests for Renal Artery Stenosis
Test Advantage(s) Disadvantage(s)
Duplex ultrasound High sensitivity
MRA Good sensitivit y and
CTA Good sensitivit y and
Captopril renal ar tery
scintigraphy
Renal vein renin Lateralizing renin
Renal catheter-based
angiography
CTA, Computed tomography angiography; NSF, nephrogenic systemic fibrosis (also
called nephrogenic fibrosing dermopathy ); MRA , magnetic resonance angiography.
Operator/experience
dependent
specificity
Operator/experience
dependent
specificity
Useful to visualize
stents
Good specificity Poor sensitivit y (~10%
predicts treatment
response
High sensitivity and
specificity
Difficult specificity in
obese patients
Increased false
positives
Not useful if stents are
present
Potential for NSF
Ionizing radiation
Iodinated contrast
to 25% false negative)
Poor sensitivity/
specificity
Invasive
Invasive
angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB) therapy; and (3) cardiovascular manifestations,
including unexplained pulmonary edema or congestive heart failure
(CHF) and refractory angina.
Although atherosclerosis comprises nearly 90% of all cases of
RAS, vasculitis and fibromuscular dysplasia (FMD) may also involve
the renal artery and may produce a stenosis. Atherosclerotic stenosis
lesions typically involve the aorta surrounding the renal artery ostium,
the ostium itself, and the proximal third of the main renal artery. FMD
usually involves the distal two-thirds of the main renal artery or its
branches. Vasculitides (involving medium vessel, such as polyarteritis
nodosa) impact the entire vessel. FMD should be suspected in individuals with early-onset HTN below the age of 30, particularly in
females.
Noninvasive Testing
Patients clinically suspected to have RAS should be referred for noninvasive assessment. Currently, the most effective modalities to screen
for RAS include renal duplex ultrasound (RADUS), MRA, and CTA
(Table 5-7). The sensitivity and specificity of RADUS are both technician and reader dependent; but, when effectively performed, the
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studies provide anatomic and functional data including renal size,
echogenicity of the renal cortex, and insight into the microvascular
disease state including the renal resistive index (RI). The renal RI,
calculated by the formula RI = peak systolic velocity (PSV) – enddiastolic velocity (EDV)/PSV or 1 – (EDV/maximal systolic velocity) ×
100, indicates the severity of microvascular renal resistance and has
been used to predict whether revascularization of the main renal
artery will confer benefit. The appropriate “cutoff” value and the utility
of using the RI calculation remain controversial. RADUS may offer
valuable anatomic and physiologic information following renal artery
stenting and is the preferred methodology for poststent surveillance.
CTA and MRA may also be highly effective strategies to image the
renal arteries, but they carry significant limitations. CTA requires the
administration of potentially nephrotoxic iodinated contrast, exposes
patients to radiation, and may not effectively discriminate extravascular calcium from intraluminal stenosis. MRA frequently overestimates
the degree of RAS, and—when performed using gadolinium—may
confer a risk for nephrogenic systemic sclerosis in patients with
advanced renal disease. Recent developments in MRA technique
provide the opportunity for imaging vascular territories without the
use of gadolinium but are not yet widely available. Captopril renal
artery scintigraphy may have specific utility in identifying patients with
unilateral RAS but is not effective in patients with abnormal GFR and
is therefore not recommended. Measurement of plasma renin levels is
not typically pursued, because elevated levels are neither a specific
nor sensitive indicator of renovascular HTN.
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Peripheral Arterial Disease and Angiography 261
Catheter-Based Angiography
Catheter-based renal angiography remains the gold standard for
imaging renal arteries and may be required to establish the diagnosis
of RAS when noninvasive findings are ambiguous. Catheter-based
angiography has a low rate of complications, but careful technique
must be employed to reduce the risks of atheroembolization, contrastrelated nephropathy, and vascular complications. Although retrograde
femoral access is most commonly employed, a brachial or radial
approach may be easier in circumstances where the renal artery origin
is angulated downward, as may commonly be the case. Acute angulation of the renal artery origin may require specialized catheters for
effective engagement. Nonselective angiography of the renal arteries
is often performed by placing a pigtail, omniflush, tennis racket, or
universal catheter in the abdominal aorta at the level of T12/L1, using
a power injection of dilute iodinated contrast and DSA. Nonselective
imaging identifies the location and number of renal arteries and may
provide critical insight into the disease status of the aorta, particularly
if complex protruding atherosclerotic lesions are imperative to avoid
during catheter manipulation. A slight left anterior oblique (LAO) projection (10 to 20 degrees) may provide the best orthogonal image of
the renal artery ostia, limiting overlap with the aorta. Alternative angiographic techniques include the use of carbon dioxide or gadolinium
as the contrast agent.
Selective renal arterial cannulation and angiographic imaging
provide the greatest amount of detail. Using an LAO 10- to 20-degree
projection may enable cannulation and optimal imaging of both renal
artery ostia in 75% of cases. The most appropriate catheter for selective
renal artery angiography depends on anatomic features in the vessel.
Soft-tipped atraumatic catheters and guidewires may reduce the risk
of vascular complications. Commonly used catheters include the internal mammary (IMA), JR4, cobra, renal double curve, hockey stick,
multipurpose, or SOS Omni. When brachial access is used for a downward angulated renal artery, advance a 6- to 7-F, 90-cm long vascular
sheath (Shuttle, Raabe, Balkan, or Ansel; Cook Medical, Bloomington,
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