rajebi2014

Critical Limb Ischemia and the Diseased Popliteal
Artery
Mohammad Reza Rajebi, MD,* and Constantino Peña, MD†
The unique anatomical location and particular biomechanical factors affecting the
popliteal artery provide a challenge to determine the proper endovascular, surgical, or
combined intervention for patients with critical limb ischemia who often require prompt
management in the presence of severe lifestyle-limiting symptoms or of the risk of limb
loss or both. Herein, we provide an overview and practical guide for endovascular
management of popliteal artery disease in the setting of critical limb ischemia.
Tech Vasc Interventional Rad 17:170-176 C 2014 Elsevier Inc. All rights reserved.
KEYWORDS CLI, popliteal artery disease, peripheral vascular disease, popliteal stents
Introduction
Lower extremity peripheral arterial disease (PAD) is a
common disease with an estimated prevalence of 30% in
patients aged 70 years and older or in those who are 50-69
years of age with a history of cigarette smoking or diabetes.1
Critical limb ischemia (CLI), deﬁned as rest pain or tissue
loss or both, is the most severe form of lower extremity
PAD. CLI requires immediate medical attention and possible intervention. The exact contribution of isolated or
concomitant popliteal artery disease in patients with CLI
is unknown, as traditionally superﬁcial femoral artery (SFA)
and popliteal artery diseases are grouped together in the
medical literature. Chronic occlusive arterial disease is the
most common etiology for CLI, while involvement in the
popliteal artery is one of the most challenging vascular beds.
The popliteal artery serves as the single arterial conduit
between the thigh and the calf, presenting a critical inﬂow
vessel into the calf and the foot. The popliteal artery can have
a signiﬁcant variability in diameter from the distal SFA to its
bifurcation into the origin of the anterior tibial artery and the
tibial peroneal trunk. Before any endovascular intervention,
the quality of the popliteal artery proximal and distal to the
lesion must always be considered for possible bypass surgery
in these patients. Additionally, other disease entities such as
popliteal artery aneurysm, entrapment syndrome, cystic
adventitial disease, or trauma can also lead to CLI.
*Department of Radiology, Mayo Clinic, Rochester, MN.
†Miami Cardiac and Vascular Institute, Miami, FL.
Address reprint requests to Constantino Peña, MD, Miami Cardiac and
Vascular Institute, 8900 North Kendall Drive, Miami, FL 33176.
E-mail: [email protected]
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The popliteal artery has traditionally been considered a
“no stent zone” particularly because of the unique biomechanical forces of the area along with the repetitive
motion of the adjacent knee joint. Traditional nitinol stents
had been thought to lack the ﬂexibility, durability, and
conformability necessary. The durability of angioplasty in
this region is extremely variable and likely related to the
morphologic characteristics of the lesions. As studied in
the femoral artery, longer calciﬁed occlusions likely
respond worse to angioplasty than their counterpart does.
The risk of dissection, coupled with the desire not to stent
in this region, has made the popliteal artery an area in
which debulking with atherectomy and the use of remodeling balloons (Cryoplasty, AngioSculpt, Chocolate, VascuTrak, Cutting) have been favored.
Patient Evaluation
The history and physical examination in patients with CLI
is important in determining eventual treatment options.
The quality of the rest pain, relieving and exacerbating
factors, and the other accompanying signs and symptoms
should be questioned. The existing ulcers should be
investigated, and the etiology of ulceration should be
determined. The arterial ulcers usually occur in the toes.
They are painful and appear dry and pale. Given the
multiplicity of medical conditions in these patients, one
should also pay special attention to other diseases that may
confound or overlap with CLI, such as diabetic neuropathy. It is important at the time of angiography to
correlate the patient's symptoms with the existing vascular
disease to determine the revascularization game plan.
1089-2516/13/$ - see front matter & 2014 Elsevier Inc. All rights reserved.
http://dx.doi.org/10.1053/j.tvir.2014.08.005
CLI and the diseased popliteal artery
Endovascular, open surgical, and combined options
should be considered as they apply to the speciﬁc patient's
symptoms and angiographic ﬁndings. In the setting of
multilevel disease, the treatment of the popliteal artery,
when involved, can be critical.
The involvement of the popliteal artery disease in patients
with CLI has been studied. A landmark study by Graziani et
al evaluated and morphologically categorized diabetic subjects with ischemic foot ulcers. In 417 consecutive patients
who underwent angiography, there were nearly 3000
lesions. More than 50% of the lesions were occlusions, of
which 75% were discovered in the tibial vessels. Of the
patients, 85% had popliteal or femoral-popliteal involvement.2 A similar study from the United States with a series of
more than 450 patients found most patients with CLI having
occlusions of the popliteal or tibial arteries.3
Indications for the Procedure
Unlike the patients with claudication, patients with CLI
require an intervention for limb salvage or to decrease the
extent of amputation. Approximately 40% of patients with
CLI who are not able to undergo revascularization will
require amputation in the next 6 months.4 As previously
mentioned, CLI usually presents a challenge given the
multilevel disease and patient's comorbidities. There are
2 major considerations in revascularization of patients with
CLI. If tissue loss, ulcer, or gangrene is present, the goal of
revascularization is to increase the blood ﬂow to the lower
extremity to provide an acceptable tissue perfusion, which is
required for the healing process. The required blood ﬂow for
tissue repair is more than the ﬂow needed to maintain the
intact healthy tissue of the extremity. However, the long-term
patency is of less importance in this critical setting. In the
presence of rest pain without tissue loss or after the healing of
ulcers, the main purpose of the intervention should be
improving the patient's symptoms, requiring additional
concern about the long-term patency of the diseased vessel.
Involvement of the popliteal artery is important in both
clinical situations. Patency of the popliteal vessel is essential
to provide inﬂow into the tibial and the pedal vessels.
Procedural Steps
The patient should be positioned supine on the ﬂuoroscopy table. Antegrade access in the ipsilateral common
femoral artery is preferred when possible as it provides
better support for the catheters and wires during difﬁcult
interventions, decreases the ﬂuoroscopy time to cross the
diseased aortic bifurcation and tortuous iliac vessels, and
requires shorter catheters and wires. Conversely, antegrade
access is more cumbersome and carries a higher risk in
obese patients. Furthermore, the use of closure devices is
not approved for this access.
With antegrade access, the patient's inguinal region as
well as the ipsilateral abdominal lower quadrant should be
prepared in advance. The access site on the skin is usually
more superior to the inguinal region. If excessive
171
abdominal fat is present, the hand that holds the access
needle is also responsible for displacing the fat superiorly
with its lateral margin. This helps to create a proper angle
and to avoid unnecessary soft tissue passage. It is important to identify the actual arterial access site with ﬂuoroscopy. Usually the distal one-third of the femoral head is
an appropriate landmark for the arterial puncture site.
Ultrasonography is a critical component of our practice in
establishing a proper arterial access.
After identifying the proper arterial access site on the
common femoral artery with ﬂuoroscopic and ultrasonographic guidance, a secure arterial access is established.
Initial angiographic evaluation of all of the lesions is
important as discussed previously. This provides the
angiographic information to assess the number, type,
and locations of the obstructing lesions as well as to
recognize the distal and proximal edges, identify the
collaterals, and evaluate the distal runoff along with the
strength and collateralization pattern within the foot.
Revascularization Options
Revascularization of a stenotic or occluded segment within
the popliteal artery follows traditional endovascular principles. Moreover, intraluminal recanalizations are essential to
avoid subintimal or reentry passages within the middle and
the distal popliteal artery. Subintimal recanalizations within
the popliteal artery increase procedural complications,
particularly at the level of the knee joint as well as near
the bifurcation into the tibial vessels, as they may cause
occlusion of vessel branches or dissections. Additionally, a
subintimal path limits the opportunity to perform atherectomy. However, maintaining an intraluminal access may be
practically impossible in some lesions, especially given the
presence of a hard cap in the proximal end of the lesion.
Retrograde pedal or tibial access may be helpful in these
situations to maintain an intraluminal path. Nevertheless,
when a subintimal recanalization is performed, maintaining a small proximal loop with the hydrophylic guidewire
is crucial to control the length of the subintimal dissection.
Additionally, reentry devices are available to not only
address the technical challenge of reentry but also help
control the location where reentry occurs, allowing the
protection of the middle and the distal popliteal artery if it
is patent. Surgical bypass is generally considered the
treatment of choice for lesions involving the middle and
the distal popliteal artery if the patient is a surgical
candidate and there is sufﬁcient venous conduit.
Traditionally, balloon angioplasty is the primary endovascular treatment for the popliteal artery lesions (Fig. 1).
Similar to the femoral artery, the use of plain old balloon
angioplasty (POBA), particularly for short, noncalciﬁed
lesions, appears to have similar patency, target lesion
revascularization (TLR) rates, and symptom improvement
scores when compared with nitinol stent placement if the
vessel responds well to the initial angioplasty. This was
demonstrated in a study that included 246 patients with
popliteal artery stenosis who were randomized to POBA
M.R. Rajebi and C. Peña
172
Figure 1 A 60-year-old man with a nonhealing ulcer of the left ﬁfth toe (Rutherford category 5). (A) Digital
subtraction angiogram (DSA) demonstrates a long segment occlusion of the popliteal artery and the tibioperoneal
(TP) trunk with reconstitution of the proximal posterior tibial artery (PTA) (arrowhead) and the peroneal artery
(arrow). (B) The lesion was crossed with the aid of a wire and a catheter, and the TP trunk and the PTA were treated
with a 2.5-mm 120-mm balloon catheter (arrow). (C) The popliteal artery was treated with a 4-mm 40-mm
balloon catheter (arrow). (D) Postangioplasty DSA demonstrates resolution of occlusion without ﬂow-limiting
dissection.
(127 patients) or nitinol stent placement (119 patients).
The study included 21% patients with CLI and 33%
patients with popliteal occlusions. The average popliteal
lesion measured 42 mm. Highlighting the risk of an
acutely unsuccessful angioplasty requiring stent placement
in the popliteal artery, 25% of patients in the POBA group
crossed over to receive nitinol stent placement because
of dissection or residual stenosis greater than 30%.
Figure 2 A 78-year-old woman with a left ﬁrst toe ulcer (Rutherford category 5). (A) Angiogram demonstrates a short
segment occlusion of the proximal popliteal artery and stenosis of the TP trunk. (B) The lesions were crossed with the aid of
a wire and a catheter, and a 6-mm 150-mm nitinol stent was deployed in the proximal popliteal artery (arrow). (C) The
distal popliteal artery and the TP trunk were treated with a 3-mm 120-mm balloon catheter (arrow). (D) Postprocedural
angiogram demonstrates resolution of occlusion and stenosis without ﬂow-limiting dissection. TP, tibioperoneal.
CLI and the diseased popliteal artery
173
Figure 3 An 84-year-old woman with rest pain involving the right lower extremity (Rutherford category 4). (A) Angiogram
demonstrates a short segment occlusion of the supragenicular popliteal. (B) The lesion was crossed with the aid of a wire
and catheter and treated with a 4-mm AngioSculpt balloon (arrow). (C) Postangioplasty angiogram shows a spiral
dissection involving the treated lesion (arrow). (D) A 6-mm 4-cm drug-eluting stent was deployed in this region.
Interestingly, based on the actual treatment received,
patients who underwent POBA had similar results when
compared with those who underwent provisional nitinol
stenting (failing POBA ﬁrst) as well as those who underwent primary nitinol stenting.5 In case of unsatisfactory
response to angioplasty, heavily calciﬁed severe lesion,
or a ﬂow-limiting dissection, stent implantation can be
used for restoration of proper blood ﬂow, especially in
the supragenicular segment of the popliteal artery
(Fig. 2).6
The opportunity to perform a safer and more effective
angioplasty has led to the creation of specialty angioplasty
balloons that aim at reducing dissections and improving
luminal diameter by scoring the plaque or controlled dilatation of the vessel. These include the Chocolate balloon (Cordis
[J&J], NJ), AngioSculpt balloon (AngioScore, Inc, CA)
(Fig. 3), and VascuTrak balloon (CR Bard, AZ) (Fig. 4) among
others. However, there are no randomized trials comparing
the true value of these balloons in the popliteal artery.
Debulking of the popliteal artery lesions with the use of
atherectomy has been used successfully as a method to
improve the vessel lumen and ﬂow. In a study that compared
atherectomy with balloon angioplasty, investigators concluded
that both techniques offer similar midterm patency, limb
salvage, and freedom from intervention despite a discrete
pattern of complications, with dissection being more common
with angioplasty vs a higher rate of thromboembolic events
with atherectomy.7 Additionally, atherectomy may be an
option to adapt the vessel wall so that it can better respond
to angioplasty (Fig. 5).
As drug-eluting technology becomes more popular, the
use of drug-eluting balloons may help increase the patency
of popliteal artery angioplasty, whereas drug-eluting stents
may increase the patency of those lesions requiring
Figure 4 A 70-year-old man with a necrotic right third toe (Rutherford category 6). (A) Angiogram demonstrates severe
stenosis of the proximal popliteal artery and multifocal stenotic lesions in the distal popliteal artery. (B) The lesions were
crossed with the aid of a wire and catheter and a 6-mm 8-mm drug-eluting stent was deployed in the proximal
popliteal artery (arrow). (C) The distal popliteal artery was treated with a 4-mm 40-mm VascuTrak balloon (arrow).
(D) Postprocedural angiogram demonstrates signiﬁcant improvement of the lesions without ﬂow-limiting dissection.
M.R. Rajebi and C. Peña
174
Figure 5 A 79-year-old woman with a right foot ulcer (Rutherford category 5). (A) Digital subtraction angiogram (DSA)
demonstrates occlusion of the proximal popliteal artery. (B) The lesion was crossed with the aid of a wire and a catheter, and
debulking was achieved using an orbital atherectomy device. (C) The popliteal artery was then treated with a 6-mm 120mm balloon catheter (arrow). (D) Postprocedural DSA demonstrates resolution of stenosis without ﬂow-limiting dissection.
stenting by reducing the risk of restenosis (Fig. 6). Studies
focusing on these trends as well as the actual effect of drugeluting technology on patients with CLI and limb salvage
rates will be helpful. The effect of drug-eluting balloons
after atherectomy to improve patency, particularly in
calciﬁed vessels, has also been studied8; however, data
on the popliteal artery are limited.
Self-expanding covered stent technology (VIABAHN,
WL GORE, AZ) has been studied extensively for long
femoral occlusive lesions as well as for the treatment of
popliteal artery aneurysms. The covered stents appear to
have responded well to the constant biomechanical motion
of the popliteal artery. The covered stents with heparin
coating have demonstrated improved patency and target
lesion revascularization rates in the femoral-popliteal segment, especially when they are appropriately sized and
expanded to the underlying vessel (Fig. 7).9 Although a
signiﬁcant correlation between the number of patent runoff
vessels and stent patency is under debate, patients'
underlying tibial disease as well as the concern for occluding collateral vessels has spurned many away from using
covered stents in popliteal lesions in patients with CLI.
The Supera stent (Abbott Vascular, CA) is a uniquely
woven nitinol stent that has demonstrated signiﬁcantly
improved radial strength and crush resistance when compared with the traditional nitinol stents. Recent trials in the
popliteal artery have demonstrated superior patency rates to
traditional nitinol stents in the popliteal artery. The rate of
stent fracture with this type of stent has been reported as
extremely low.10 The data from the randomized Surgical
Versus Percutaneous Bypass Trial are pending publication.
Recognizing and Treating
Complications
Thromboembolic events, restenosis, stent stenosis, and
stent fractures are the main complications of endovascular
CLI and the diseased popliteal artery
175
Figure 6 A 63-year-old man with a nonhealing ulcer of the left ﬁfth toe. (A) DSA demonstrates occlusion of the
genicular popliteal artery. (B) After an unsuccessful attempt via an antegrade access, the lesion was crossed with the
aid of a wire and a catheter via a pedal access through the dorsalis pedis artery. (C) A 6-mm 80-mm drug-eluting
stent was deployed in the popliteal artery (arrow). (D) Postprocedural angiogram demonstrates resolution of the
occlusion without ﬂow-limiting dissection. DSA, digital subtraction angiogram.
interventions in patients with CLI. The length and diameter of the balloons and stents, the crossing of distal
collateral vessels, and the number of patent runoff vessels
have been described as important factors for patency.
Additionally, patients' comorbidities such as diabetes and
end-stage renal disease as well as the inability to tolerate
dual antiplatelet therapy are thought to increase the risk of
stent failure.11
Figure 7 A 77-year-old woman with left ﬁfth toe gangrene (Rutherford category 6). (A) Digital subtraction
angiogram (DSA) demonstrates severe stenosis of the proximal popliteal artery and occlusion of the distal popliteal
artery. (B) The TP trunk reconstitutes distally. The anterior tibial artery also reconstitutes but again occludes
proximally (arrow). (C) The lesions were crossed with the aid of a wire and a catheter, and the popliteal artery was
treated with a 5-mm 50-mm covered stent graft (arrow). (D) The distal popliteal artery, TP trunk and proximal
PTA, and peroneal artery were treated using 2 kissing balloons of 2.5 mm 120 mm. (E) Postprocedural DSA
demonstrates resolution of the proximal stenosis and interval establishment of ﬂow in the distal popliteal artery
and the TP trunk. TP, tibioperoneal.
M.R. Rajebi and C. Peña
176
Acute thromboembolic events can be managed with
thrombolysis. Restenosis after angioplasty may respond to
repeat angioplasty or stent placement. Angioplasty and
stent relining can be effective methods of treatment.
Surgical interventions should be reserved for severe cases
of stent fractures and failure of endovascular options.
Clinical Follow-Up
In our practice, the patients are evaluated with a noninvasive arterial duplex study with pulse volume recording
at rest after the procedure on the same day or the day after
the intervention. The patients are placed on proper
antiplatelet therapy based on the intervention they
received and the type of stent implanted. Dual antiplatelet
therapy with aspirin and clopidogrel for 6 months is
prescribed for patients with stent grafts. The initial postprocedure visit is scheduled at 1 month after the procedure
with a repeat noninvasive study. After the initial visit, the
patient is followed up at 6 months and 1 year after the
procedure. The patients are instructed to contact our ofﬁce
in case of worsening symptoms or new ones.
Conclusion
Management of popliteal artery disease in the setting of
CLI presents an extremely controversial topic. This is
partly related to the lack of randomized clinical trials
speciﬁc for the popliteal artery given its unique anatomical
and biomechanical characteristics, which discerns it from
the SFA. Today, most interventionalists only treat the
popliteal artery when there is a clear indication. Balloon
angioplasty and, when possible, surgical bypass remain the
best options. Nonetheless, with the advent of drug-eluting
balloons and stents as well as the introduction of more
durable stent designs and new atherectomy devices, there
will likely be more options available to be offered for
patients with severe PAD. Further investigations comparing these advanced options and balloon angioplasty with
focus on popliteal artery are required to establish an
evidence-based approach.
References
1. Hirsch A, Criqui M, Treat-Jacobson D, et al: Peripheral arterial
disease detection, awareness, and treatment in primary care. J Am
Med Assoc 286:1317-1324, 2001
2. Graziani L, Silvestro A, Bertone V, et al: Vascular involvement in
diabetic subjects with ischemic foot ulcer: A new morphologic
categorization of disease severity. Eur J Vasc Endovasc Surg
33:453-460, 2007
3. Rueda CA, Nehler MR, Perry DJ, et al: Patterns of artery disease in
450 patients undergoing revascularization for critical limb ischemia:
Implications for clinical trial design. J Vasc Surg 47:995-999, 2008
4. Hirsch AT, Haskal ZJ, Hertzer NR, et al: ACC/AHA 2005 Practice
Guidelines for the management of patients with peripheral arterial
disease (lower extremity, renal, mesenteric, and abdominal aortic): A
collaborative report from the American Association for Vascular
Surgery/Society for Vascular Surgery, Society for Cardiovascular
Angiography and Interventions, Society for Vascular Medicine and
Biology, Society of Interventional Radiology, and the ACC/AHA Task
Force on Practice Guidelines (Writing Committee to Develop
Guidelines for the Management of Patients With Peripheral Arterial
Disease): Endorsed by the American Association of Cardiovascular
and Pulmonary Rehabilitation; National Heart Lung, and Blood
Institute; Society for Vascular Nursing; TransAtlantic Inter-Society
Consensus; and Vascular Disease Foundation. Circulation 113:
e463-e654, 2006
5. Rastan A, Krankenberg H, Baumgartner I, et al: Stent placement
versus balloon angioplasty for the treatment of obstructive lesions of
the popliteal artery: A prospective, multicenter, randomized trial.
Circulation 127:2535-2541, 2013
6. Muradin GS, Bosch JL, Stijnen T, et al: Balloon dilation and stent
implantation for treatment of femoropopliteal arterial disease: Metaanalysis. Radiology 221:137-145, 2001
7. Semaan E, Hamburg N, Nasr W, et al: Endovascular management of
the popliteal artery: Comparison of atherectomy and angioplasty.
Vasc Endovascular Surg 44:25-31, 2010
8. Cioppa A, Stabile E, Popusoi G, et al: Combined treatment of heavy
calciﬁed femoro-popliteal lesions using directional atherectomy and
a paclitaxel coated balloon: One-year single centre clinical results.
Cardiovasc Revasc Med 13:219-223, 2012
9. Lammer J, Zeller T, Hausegger KA, et al: Heparin-bonded covered
stents versus bare-metal stents for complex femoropopliteal artery
lesions: The randomized VIASTAR trial (Viabahn endoprosthesis
with PROPATEN bioactive surface [VIA] versus bare nitinol stent in
the treatment of long lesions in superﬁcial femoral artery occlusive
disease). J Am Coll Cardiol 62:1320-1327, 2013
10. León LR Jr, Dieter RS, Gadd CL, et al: Preliminary results of the
initial United States experience with the Supera woven nitinol stent
in the popliteal artery. J Vasc Surg 57:1014-1022, 2013
11. Johnston PC, Vartanian SM, Runge SJ, et al: Risk factors for clinical
failure after stent graft treatment for femoropopliteal occlusive
disease. J Vasc Surg 56:998-1006, 2012