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24 Lower Extremity Arterial Reconstruction inPatients withDiabetes Mellitus: Principles ofTreatment
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439
due to risk of nephrogenic systemic brosis [39, 44]. With
these considerations in mind, arteriography need not be
withheld due to fear of exacerbating moderate chronic renal
insufciency.
Framework forApproach
toRevascularization
Crafting a strategy for revascularization depends on a thorough evaluation of patient risk, limb severity, and anatomic
distribution of disease though history, exam, and imaging, as
detailed above.
The ultimate goal of lower extremity revascularization is
to restore sufcient perfusion to produce ulcer healing. The
general consensus is that short stenoses or occlusions are
suitable for endovascular techniques while long segment disease is best treated with surgical bypass. This was previously
formalized by the anatomic Trans-Atlantic Inter-Society
Consensus (TASC) classication system. [45, 46] This system categorized aortoiliac and femoropopliteal occlusive
disease into classes A-D based on complexity. Endovascular
intervention was deemed the treatment of choice for TASC A
and the preferred strategy for TASC B and surgery preferred
for TASC C and the treatment of choice for TASC D lesions.
This classication system is limiting however as it considers
the aortoiliac and femoropopliteal segments in isolation, and
therefore has limited utility in patients with multilevel disease or diabetic patients with infrapopliteal disease.
More recently, the 2019 Global Vascular Guidelines on
Critical Limb-Threatening Ischemia have proposed a new
classication system: the Global Anatomic Staging System
(GLASS) which replaces the previous TASC classication
[47]. GLASS requires the selection of a preferred target artery
path (TAP) to achieve in line ow from the groin to the ankle.
Assuming that inow disease is addressed, a GLASS stage is
determined based on assessment of the femoropopliteal segment and infrapopliteal disease complexity, with an inframalleolar modier to account for pedal disease. This paradigm of
disease staging shifts the focus from primary patency of a specic intervention to limb-based patency (LBP), i.e., maintenance of the revascularization through the entire TAP.GLASS
stage has been shown to predict rates of technical success and
limb-related outcomes in several large studies [48, 49].
Once the anatomic staging is complete, the choice
between open and endovascular revascularization will ultimately depend on individualized patient and limb factors, as
well as the treating surgeon’s experience with both techniques. Patency of the TAP is one metric by which to measure the success of a revascularization attempt. However,
success can also be dened by time to wound healing,
resumption of ambulation, and prevention of ulcer recurrence. Thus, it is critical to consider the extent of tissue loss
and time required to heal a wound when selecting a
revascularization strategy. A small toe ulcer may only require
a tibial angioplasty with a 6-month patency to heal, whereas
a large wound will require a more durable revascularization
such as a bypass. Finally, to ensure successful wound healing, patients must be followed with regular surveillance
imaging with constant reevaluation and restaging of the limb.
Endovascular Revascularization
Techniques
If after the diagnostic angiogram, an endovascular approach
is chosen, the 4-French sheath is exchanged for a longer (45–
90cm) 5-or 6-French sheath that provides stable access over
the bifurcation and into the leg of interest. Some interventionalists may prefer using antegrade arterial access for distal
lesions. Both approaches are acceptable with some limitations for each. Intravenous heparin is infused as a bolus in a
dose of 80–100units/kg and an activated clotting time (ACT)
is checked periodically. We routinely maintain an ACT
greater than 250s for aortoiliac and femoropopliteal interventions, or greater than 300s for tibial interventions. Once
fully anticoagulated, various wires and supporting catheters
can be utilized in a coaxial fashion to cross stenoses or occlusions. Every effort is made to keep the wire within the vessel
lumen when crossing a lesion. However, it is sometimes necessary to cross an occluded vessel in a subintimal plane and
re-enter distally at a site of less diseased artery. Short stenoses may respond well to balloon angioplasty alone [Figs.
24.6 and 24.7]. In the aortoiliac and femoropopliteal seg-
ments, long, calcied stenoses or occlusions are likely to
have residual luminal compromise even after balloon angioplasty and may require stent placement. In the femoral popliteal segment, drug coated stents and balloons are available
that likely confer a slight patency advantage compared to
untreated devices [50–53]. Unfortunately, there are currently
no such drug-coated balloons or stents that are sized for
treatment of the tibial vessels. Stenosis or occlusions of tibial
vessels are most commonly treated with balloon angioplasty
alone [Fig. 24.8] with balloon diameters ranging from
1.5mm to 3mm and lengths from 20mm to 200mm. Despite
a wide variety of atherectomy devices that can facilitate
angioplasty, their use does not confer any patency advantage
over conventional balloon angioplasty alone. Typically, a
single tibial target is treated if it provides pulsatile ow to the
ankle and transitions into the pedal circulation. Occasionally
peroneal artery revascularization will sufce if there are adequate forefoot or hindfoot collateral branches that perfuse
the foot. Some proceduralists advocate treating more than
one tibial vessel or the plantar arch but there is no data to
support this on a routine basis. Angiography is repeated fol-
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Fig. 24.6 (a) Percutaneous angiogram showing occlusion of right tib-
ioperoneal trunk (TPT) and three tibial vessels. (b) Balloon angioplasty
of TPT stenosis. (c) Balloon angioplasty of posterior tibial artery origin
lowing angioplasty or stenting to evaluate the success of the
intervention and to assess for complications including dissection and distal embolization. There are no available selfexpanding stents currently available for the treatment of
residual stenosis or dissection. In this situation, a balloon
expandable coronary stent can be considered.
In some cases, in may be impossible to cross an infrapopliteal stenosis or occlusion from an antegrade approach
(either from ipsilateral or contralateral femoral access) but
there may be a patent distal tibial or pedal vessel that reconstitutes via collateral ow on angiography. Though this
anatomic pattern of disease has typically been best served
with bypass surgery, CLTI patients who are at high surgical
risk or those who lack appropriate conduit can be considered for retrograde pedal access to facilitate endovascular
treatment of previously un-crossable tibial artery occlusions [54]. In our experience, this technique has been
required with increasing frequency in patients with complex tibial disease, after standard endovascular approaches
have been attempted [Fig. 24.9].
Deep vein arterialization for limb salvage patients without
other conventional endovascular or surgical bypass options has
recently re-emerged. The initial description of this technique is
attributed to Halstead in 1912 and involves arterial pressurization of the venous capillary bed in order to improve tissue perfusion. Initial techniques of AV stula creation or an arterial
stenosis. (d) Completion angiogram showing restoration of in-line ow
to the posterior tibial artery
bypass into a venous target have long been abandoned but there
has been renewed interest in a purely percutaneous option.
Percutaneous deep vein arterialization (DVA) is a technique
that creates an arteriovenous connection, usually between the
posterior tibial artery and vein. From this connection, stentgrafts are used to reline the posterior tibial vein down to the
level of the ankle. This reversal of ow within the venous system is allowed to perfuse the foot once the nal venous valves
in the plantar arch are disrupted. This has been used in patients
with “desert foot” where there are no patent pedal arteries for
conventional revascularization [Fig. 24.10]. The foot must be
stable enough to for several weeks while the foot improves so
proper patient selection is critical. Initial results in single arm
trials using the commercially available devices (Limow, Inc.
San Jose, CA) as well as off-the-shelf devices are sparse [55,
56] but appear to suggest some benet in very well selected
patients and randomized controlled trials are ongoing [57].
Outcomes
The Bypass versus Angioplasty for Severe Ischaemia of the
Leg (BASIL) trial was the rst randomized, multicenter, prospective trial comparing angioplasty to bypass for critical limb
ischemia due to infrainguinal arterial occlusive disease [58–
60]. Though the endovascular techniques utilized in the percu-
ab
24 Lower Extremity Arterial Reconstruction inPatients withDiabetes Mellitus: Principles ofTreatment
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Fig. 24.7 (a) Pretreatment
angiogram showing longsegment left posterior tibial
artery occlusion. (b)
Completion angiogram
showing patent posterior tibial
artery following angioplasty.
Wide collateral network lls
less robustly now that in-line
ow has been re-established
in the PT
441
taneous transluminal angioplasty (PTA) arm are now fairly
outdated, at 2 years follow up, mortality, limb salvage, and
survival were identical for the two groups. The cost of bypass
was found to be higher but the PTA group required reintervention more frequently. Surprisingly, functional outcomes and
quality of life measures were identical for both groups. In a
post hoc analysis of patients surviving beyond 2years, limb
salvage and survival were higher for patients undergoing
bypass. In spite of its shortcomings, this study validated the
use of tibial angioplasty for critical limb ischemia especially
for those patients with strong contraindications to surgery or
anesthesia and with an anticipated life expectancy of less than
2years. The recently published BEST-CLI trial, discussed in
more detail later, has demonstrated that endovascular intervention has equivalent outcomes to bypass in patients with no
suitable single-segment vein conduit for bypass but otherwise
re-afrms the role of bypass.
In our initial published series of infrapopliteal angioplasty in 176 limbs with CLTI, technical success was
achieved in 93% of patients overall and was noted to be
related to lesion length: it was 100% for short, focal stenoses (1–4cm) or occlusions (< 2cm) but decreased to 75%
for longer occlusions or diffusely diseased arteries. Patency
of the treated vessel at 1year was only 39% but limb salvage was 84% [61].
Following this report, we updated our institutional experience performing infrapopliteal angioplasty for patients with
CLTI [62]. Over an 8year period, infrapopliteal PTA was performed in 459 limbs (average age 71 years). Of the 413
patients treated, comorbid diabetes was present in 75%.
Technical success (residual stenosis <30%) was achieved in
93% of limbs. The 30-day mortality rate was found to be 6%
and when only surgical candidates were considered, the
30-day mortality was slightly lower at 4%. In long-term follow- up, survival at 1, 3, and 5years was 83%, 64%, and 49%
respectively [Fig. 24.11]. Diabetes was not found to be an
independent predictor of perioperative or long-term mortality.
At 1-year follow-up, primary patency was 57% and limb salvage was 84% and at 5-years follow-up, primary patency was
34% and limb salvage was 81%. Restenosis rate at 5years
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S. X. Wang and M. C. Wyers
Fig. 24.8 (a, b) Subtracted pre-treatment angiogram showing long segment occlusion of right anterior tibial artery with reconstitution of dorsalis
pedis. (c, d) Subtracted angigoram showing patent AT following balloon angioplasty
Fig. 24.9 (a) Subtracted
pre-treatment angiogram
showing long segment
occlusion of right popliteal
artery which was not
amenable to antegrade
crossing via contralateral
femoral access. (b)
Retrograde access to the
anterior tibial artery facilitates
(c) retrograde crossing of the
lesion. Note that anterograde
access is maintained with
wire in the above knee
popliteal
was found to be 74%. Perhaps not surprisingly, worse outcomes were associated with more advanced occlusive disease, as indicated by TASC I classication [63], a nding
which has been shown in other small series as well [64, 65].
The incongruity between excellent limb salvage rates and
high restenosis rates is partially explained by the frequency
ab c
and presumed efcacy of reintervention. Of all patients
treated, 50% required repeat PTA and/or bypass at 5 years
follow-up. These ndings reinforce the need for continued
surveillance and likelihood of repeat interventions in patients
undergoing infrapopliteal angioplasty. The mortality rate of
4% in patients who are also surgical candidates challenges the
ef
100%
433 342 253 186115 88 50 32 1
Number at r
ve
24 Lower Extremity Arterial Reconstruction inPatients withDiabetes Mellitus: Principles ofTreatment
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443
Fig. 24.10 (a) Pretreatment angiogram demonstrating “desert foot”
with no DP or PT in the foot. (b) Percutaneous deep vein arterialization
performed through venous access in the posterior tibial and arterial
access to the common femoral artery. (c) Gooseneck snares in the posterior tibial artery and posterior tibial vein are aligned on uoroscopy. A
micropuncture needle is advanced transcutaneously through both snares
to create the arteriovenous stula. (d) Contrast angiogram conrms cre-
83%
75%
50%
Overall Survival
25%
0%
02
isk
Fig. 24.11 Long-term survival following infrapopliteal angioplasty.
Adapted from Lo, et al. J Vasc Surg. 2013;57(6):1455–63
72%
64%
54%
49%
42%
SE does not exceed 10% for any cur
345
Years
6781
notion that endovascular tibial interventions are safer than
surgical bypass. For context, in our institutional report on
1000 cases of dorsalis pedis bypass (average age 66.8years),
a 30-day mortality rate of 0.9% was reported [66].
Others have reported their experience with infrapopliteal
angioplasty as well. In a meta-analysis of infrapopliteal
angioplasty for critical limb ischemia, more than 2500
patients were included, of which 61% had diabetes [67].
Technical success rate was estimated to be 89% and primary
patency rates were 77% and 49% at 1 and 3years, respectively. Similar to our reported experience, limb salvage rates
were 93% at 1year and 82% at 3years indicating acceptable
limb salvage rates in the setting of frequent restenosis.
ation of an arteriovenous stula with placement of a balloon expandable
stent across the stula. (e) After stenting of the posterior tibial vein with
a Viabahn from stula to the PT vein at the ankle, wire access through
stula into posterior tibial vein and veins of the foot allows for valvulotomy performed with cutting balloons through to the anterior tibial
vein. (f) Completion angiogram following percutaneous deep vein arterialization demonstrating signicantly improved ow in the foot
For comparison, the authors also performed a metaanalysis of popliteal-dorsalis pedis bypass and found that the
limb salvage rate was comparable at 3years (82.3% bypass
vs. 82.4% PTA) [68]. Based on the results of the BASIL trial,
3years of follow-up should be adequate to show differences
between treatment modalities. These non-randomized results
are encouraging, and suggest that endovascular interventions
for infrapopliteal occlusive disease may be comparable to
bypass in well selected patients.
Importantly, adjunctive technologies including drugcoated balloon angioplasty and drug-eluting stents have
developed considerably in recent years [69]. Initial enthusiasm for drug-coated balloon (DCB) angioplasty in infrapopliteal arteries has diminished as the results of the
INPACT-DEEP trial have become available [70]. This is the
largest randomized trial of DCB vs. PTA and showed no
additional benet to paclitaxel DCB at 12 months and at
5years [50]. In fact, in the INPACT-DEEP study, DCB was
associated with a trend towards higher rates of major amputation compared to PTA. There is currently no compelling
evidence that DCB has any additional benet compared to
PTA in this setting [69, 71]. However, recent data from the
PRESTIGE study of the sirolimus-eluting balloon used
below the knee for CLTI patients with TASC C and D lesions
has demonstrated promising short-term patency, renewing
the interest in DCB technology for tibial disease.
Results regarding the use of drug-eluting stents (DES) have
been more uniform. Four RCTs using drug eluting stents in the
supercial femoral and proximal popliteal arteries have shown
excellent primary patency for DES at 1-year follow-up [72–
76]. Similarly, the Dutch PADI trial has demonstrated
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Location of lesions: Infrapopliteal
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S. X. Wang and M. C. Wyers
improved patency and limb salvage rates with DES (paclitaxel, balloon expandable coronary stents) versus angioplasty
with or without bare metal stenting in the below knee segment
[77]. Taken together, these studies have shown that DES
appears to demonstrate clinically relevant improvements in
patency, reduced reintervention rates, and reduced amputation
rates over PTA and bare metal stenting [78–82]. However, longer and more complex stenoses and occlusions may not be
amenable to extensive stenting and, as our own experience has
shown, these are the lesion types that are prone to failure with
endovascular therapy. As DES becomes more widely available
for use, the anatomic situations in which DES deployment is
most useful should be carefully considered.
Endovascular
procedure
Major amputation (1 year follow-up)
Atherectomy
Drug eluting Stent
Drug eluting balloon
Plain old balloon angioplasty
Plain old balloon angioplasty
Stent bare metal
Major amputation (3 year follow-up)
Drug eluting Stent
Plain old balloon angioplasty
Plain old balloon angioplasty
Stent bare metal
± Stent bare metal
± Stent bare metal
Number of
studies
2
6
2
7
1
5
3
1
1
1
number of
patients
95
468
310
554
66
307
254
48
66
41
Although there are is a large armamentarium available
for the endovascular treatment of CLTI, there is a relative
scarcity of comparative trials. It can be difcult to decide
between competing strategies. Almasri etal. recently published an excellent meta-analysis of 44 trials comparing
outcomes in CLTI patients [83]. In the infrapopliteal segment, bare metal stenting (BMS) and DES were associated with the lowest 3-year amputation rates. Three-year
primary patency was signicantly higher for DES compared to BMS.Overall three-year mortality rates for DES,
angioplasty, angioplasty with BMS, and BMS were similar [Fig. 24.12].
Proportion (95% CI)
0.05 (0.02, 0.15)
0.04 (0.01, 0.14)
0.08 (0.05, 0.13)
0.08 (0.03, 0.25)
0.20 (0.11, 0.31)
0.07 (0.02, 0.25)
0.12 (0.06, 0.24)
0.23 (0.12, 0.37)
0.23 (0.13, 0.35)
0.17 (0.07, 0.32)
Mortality (1 year follow-up)
Atherectomy
Drug eluting Stent
Drug eluting balloon
Plain old balloon angioplasty
Plain old balloon angioplasty
Stent bare metal
Mortality (3 year follow-up)
Drug eluting Stent
Plain old balloon angioplasty
Plain old balloon angioplasty
Stent bare metal
Primary patency (1 year follow-up)
Atherectomy
Drug eluting Stent
Plain old balloon angioplasty
Plain old balloon angioplasty
Stent bare metal
Primary patency (3 year follow-up)
Drug eluting Stent
Plain old balloon angioplasty
Stent bare metal
Secondary patency (1 year follow-up)
Drug eluting Stent
Plain old balloon angioplasty
± Stent bare metal
± Stent bare metal
± Stent bare metal
± Stent bare metal
2
6
2
7
1
5
3
2
1
1
2
6
3
1
5
2
1
1
1
1
95
452
304
662
66
297
242
263
66
41
166
408
205
71
262
115
39
41
66
72
0.07 (0.03, 0.17)
0.17 (0.11, 0.27)
0.10 (0.07, 0.14)
0.15 (0.11, 0.22)
0.24 (0.15, 0.36)
0.15 (0.11, 0.20)
0.33 (0.26, 0.42)
0.31 (0.15, 0.65)
0.47 (0.35, 0.60)
0.32 (0.18, 0.48)
0.78 (0.72, 0.85)
0.73 (0.65, 0.81)
0.66 (0.51, 0.85)
0.42 (0.31, 0.55)
0.50 (0.42, 0.60)
0.49 (0.31, 0.79)
0.21 (0.09, 0.37)
0.10 (0.03, 0.23)
0.65 (0.52, 0.77)
0.56 (0.43, 0.67)
Fig. 24.12 Forest plot demonstrating outcomes following endovascular intervention for infrapopliteal lesions. (Adapted from Almasri, etal. J
Vasc Surg. 2019;69(6):126S–136S)
.1 .2 .3 .4 .5 .6 .7 .8 .9 1
0
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Surgical Revascularization
Technique
A patient deemed to be a good candidate for surgical bypass
must have an adequate inow source and outow target
artery, both of which are typically determined using diagnostic DSA.The outow target artery at the location of the distal
anastomosis should be relatively free of occlusive disease
and demonstrate unimpeded arterial ow into the arteries of
the foot. In general, the most proximal artery distal to an
occlusion meeting these two criteria is chosen as a bypass
target vessel. Distal arterial reconstructions present special
technical challenges for the vascular surgeon and require
meticulous attention to detail [Fig. 24.13]. The target arteries
are usually small, approximately 2.0 millimeters in diameter,
and are often affected by medial calcication.
Vein bypass grafts for chronic limb-threating ischemia
have well established safety and efcacy. Perioperative
mortality in most contemporary series ranges from 1% to
5% and limb salvage may approach 90% at 5years for many
patients [84, 85]. Although these results are excellent, they
do not reect the high cost of recovery for many patients to
achieve this outcome. Wound morbidity is common ranging
from 10 to 50% [86, 87]. Limb swelling, delayed healing of
ischemic wounds, and the need for additional procedures
may delay full recovery for many months. In our study evaluating quality of life measures in patients undergoing arterial bypass for limb salvage, less than 50% reported feeling
they were back to normal 6months after surgery [88]. In a
similar study, only 15% of patients achieved the ideal outcome of a patent graft with no need for revision, no wound
complications, and a healed foot following bypass. These
observations are especially sobering when considering the
fact that 50% of patients survive less than 5years after their
limb salvage procedure [89].
One of the most important developments in vascular surgery has been the demonstration that autogenous saphenous
vein, as opposed to prosthetic graft material, gives the best
short–and long-term results for distal bypass. In a large
multi-center prospective randomized clinical trial, 6-year
patency of saphenous vein grafts was more than four times
higher than that of prosthetic grafts [90]. For over six
decades, the standard graft orientation performed for lower
extremity arterial revascularization has been the reversed
saphenous vein bypass. The vein is completely harvested and
its distal end is translocated to the proximal anastomotic site
in order to prevent the impediment of ow from intact venous
valves. For tibial bypass especially, this often creates a size
discrepancy between the venous conduit and the inow and
target arterial anastomoses. To avoid this problem and minimize vein harvest trauma, valvulotomy was developed to
render the valves incompetent. This allows the vein to be
used as a non-reversed conguration. A non-reversed graft
can be similarly excised, translocated, tunnelled, or left
within its native position as an “in-situ” conguration. In the
late 1970s, Leather and associates popularized this technique
using a modied Mills valvulotome that atraumatically cuts
the valves to render them incompetent [91]. Vascular surgeons enthusiastically embraced the Leather technique and
Fig. 24.13 Intraoperative photograph of a femoral to posterior tibial bypass using non-reversed greater saphenous vein. (Courtesy of Mark Wyers, MD)
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Fig. 24.14 Intraoperative photograph of vein angioscopy for evaluation of vein quality and valvulotomy. (Courtesy of Mark Wyers, MD)
began reporting improved results with the non-reversed, in
situ bypass compared with the conventional reversed vein
approach [92–94]. This led some to conclude that the in situ
bypass possesses inherent biologic superiority to the reversed
saphenous vein graft [95]. However, further evidence to support this concept has not been presented [96]. Moreover,
when in situ bypasses are compared to more contemporary
series of reversed saphenous vein bypasses, no superiority is
evident [97]. In our own experience, we have frequently used
both procedures and have observed similar results with either
vein conguration [98]. We also routinely perform angioscopy to evaluate the overall vein quality and to perform valvutotomy under direct vision, favoring this over blind
valvulotomy techniques [Fig. 24.14]. Flexible valvulotomes
are used for in situ grafts and a traditional Mills valvulotome
is used for completely harvested grafts.
In the 1980s Ascher and associates reported the rst series
of bypass grafts with inow taken from the popliteal artery
[99]. Because atherosclerotic occlusive disease often spares
the supercial femoral artery in diabetes, the popliteal artery
can be readily used as a source of inow for the bypass graft.
Doing so shortens the operative procedure time, shortens the
length of the bypass, and avoids potentially troublesome
groin wound complications, which often accompany thigh
and groin dissections. Short vein grafts are also advantageous in patients who have a limited quantity of adequate
saphenous vein. Frequently, thigh saphenous vein is harvested and translocated to the lower leg to avoid parallel
incisions between the distal vein harvest site and target artery
exposure. They showed results that were equivalent to those
of the traditional approach that preferentially used the common femoral artery. Such results have been conrmed by
other groups and this technique has proven to be another
important advancement in arterial reconstruction for patients
with diabetes [100, 101]. Our experience with extreme distal
arterial reconstructions has shown that popliteal artery inow
is possible in about 60% of diabetic patients undergoing vascular reconstruction in the lower extremity [98].
Ipsilateral, single-segment greater saphenous vein is the
conduit of choice for infrainguinal leg bypass. When the
ipsilateral saphenous vein is unavailable due to varicosities,
previous harvesting, or stripping, alternative sources of conduit must be used. Although some surgeons use prosthetic
grafts in these circumstances, alternative vein grafts including contralateral greater saphenous vein, arm vein, or lesser
saphenous vein can be used. In patients with an absent ipsilateral greater saphenous vein, the likelihood of requiring
another arterial reconstruction in the opposite extremity
approaches 40% at 3 years following the rst operation
[102]. Because of this, some surgeons hesitate to harvest the
contralateral saphenous vein even though it remains the better option [103].
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When saphenous vein is unavailable bilaterally, our vein
conduit of choice is cephalic or basilic vein. Our results with
arm vein grafts have been improved by examining the vein
with intraoperative angioscopy to exclude segments with
strictures or scarring from trauma commonly induced by previous venipuncture or thrombosis [104] [Fig. 24.14]. Using
the angioscope to evaluate the quality of arm vein conduit
has signicantly improved our results and further reduces the
number of patients requiring prosthetic conduit [105].
Although arm vein is a reasonable conduit in most patients,
we hesitate to harvest arm vein for leg bypass in patients
with end-stage renal disease given the need potential arteriovenous access surgery. One potential disadvantage of arm
vein conduits is their limited length. The use of popliteal
artery inow makes the use of shorter arm vein grafts possible in many patients. Moreover, in carefully selected patients,
the use of composite grafts made by combining vein segments can provide enough conduit length to reach from the
groin to the distal tibial and even foot vessels in many
patients [31]. Our results with arm vein grafts in over 500
procedures have been reported [106]. Patency was 57.5%
and limb salvage was 71.5% at 5years. These results were
inferior to those with reconstructions done with saphenous
vein, however signicantly better than those reported with
prosthetic conduits.
A recent report on the outcomes of tibial bypass with
prosthetic graft, heparin bonded polyuorotetraethylene
(ePTFE), versus saphenous vein conduit noted a signicant
improvement in patency rates associated with saphenous
vein use. Patency of the graft was 75% with ePTFE versus
86% with saphenous vein graft during the follow-up period
that ranged from 1 to 12months [107]. Large metanalyses
also demonstrate that saphenous vein is superior to prosthetic grafts with lower amputation rates and higher primary
and secondary patency out to 3 years after infrapopliteal
bypass [Fig. 24.15]. This demonstrates the patency advantage of using saphenous vein when available despite the
advances in prosthetic graft construction.
Although the current guidelines recommend single antiplatelet therapy following lower extremity bypass [47, 108],
there is signicant heterogeneity in the prescribed antithrombotic regimen following lower extremity bypass. Escalating
regimens are typically used to improve patency of prosthetic
or disadvantaged vein bypasses. Dual antiplatelet therapy
has been demonstrated to improve patency of prosthetic
grafts, [109] and the recent VOYAGER trial has demonstrated a reduction in major cardiac and limb events following revascularization in patients randomized to low dose
rivaroxaban plus aspirin, compared to aspirin alone [110,
111]. Our recent observational study on antithrombotic ther-
apy following infrapopliteal bypass for CLTI demonstrated
no signicant reduction in major adverse limb events with
antithrombotic regimens beyond an antiplatelet alone [112].
In general, the goal of treatment is to restore maximal
arterial ow to the foot since this provides the best chance
for healing. The preoperative diagnostic arteriogram is the
key piece of information necessary in planning the appropriate surgical procedure for each patient. If a bypass to the
popliteal or tibial artery will restore maximal arterial ow
and restoration of palpable foot pulses, bypasses need not
extend to the level of the foot. Since the quality of venous
conduit is the most important determinant in long-term success, using the shortest length of high-quality venous conduit
necessary to achieve this goal is the basic rule. Each operation must be individualized based on the patient’s available
venous conduit and arterial anatomy.
Outcomes
The BEST-CLI (Best Endovascular versus Best Surgical
Therapy for Critical Limb Ischemia) is the largest, most contemporary randomized clinical trial designed to compare
outcomes after open and endovascular revascularization in
the CLTI population [113]. In the recently published results,
1830 patients were randomized in two cohorts to bypass or
endovascular revascularization based on availability of vein.
The primary outcome was a composite of major adverse
limb events and all-cause mortality. For patients who had
single-segment great saphenous vein available for conduit,
those who received surgery had signicantly lower risk of a
major adverse limb event or death (43% vs. 57%, HR 0.68)
over a median follow-up of 2.7years. However, in the cohort
of patients who did not have single-segment GSV available,
both groups had similar rates of adverse outcomes.
Based on these trial results, it is clear that in CLTI patients
with acceptable surgical risk and adequate GSV, surgical
bypass should be the initial revascularization strategy.
Bypass has superior outcomes over 3 years compared to
endovascular interventions in this subgroup. However, the
initial strategy in patients without adequate vein is not so
clear—consideration of the individual patient’s risk, anatomy, and limb severity is required to select the optimal
approach.
The independent effect of diabetes on outcomes in
patients undergoing surgical bypass is controversial and continues to be debated. Although the majority of patients in
BEST-CLI (>70%) were diabetic, an analysis of outcomes
by diabetic status has not yet been published. In the
PREVENT III trial, 1404 patients underwent bypass for CLI,
of which 64% had diabetes [114]. The authors found that
diabetes status did not affect graft patency. Congruent with
these results was the nding that when optimal vein conduit
was used, there were no signicant differences in patency
between femoropopliteal bypasses and distal bypasses (tibial
or pedal target vessels) [114, 115]. Our institutional experi-
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S. X. Wang and M. C. Wyers
Fig. 24.15 Forest plot demonstrating outcomes following bypass surgery for infrapopliteal lesions. (Adapted from Almasri, etal. J Vasc Surg.
2019;69(6):126S–136S)
ence with greater than 800 lower extremity bypass procedures has also shown no independent effect of comorbid
diabetes on outcomes [116] [Fig. 24.16]. Our updated analysis of institutional experience with 650 rst-time lower
extremity bypass for CLTI has also demonstrated no impact
of diabetes (regardless of insulin dependence) on graft
patency or reintervention rate. Although insulin-dependent
diabetes (IDDM) was associated with incomplete wound
healing and higher amputation rate following initial endovascular intervention, IDDM was only associated with poor
wound healing but equivalent limb salvage outcomes after
bypass, suggesting that a bypass rst strategy may be more
suitable in IDDM patients [117].
Findings from PREVENT III, CIRCULASE, and BASIL
trials were combined by the Society for Vascular Surgery to
formulate objective performance goals for bypass surgery
[15]. This analysis included only the highest quality randomized, controlled data of patients undergoing bypass with
autogenous vein. The investigators found that older patients
(age>80) and patients with tissue loss should be considered
“clinical high risk” due to demonstrably worse outcomes at
1 year follow-up. Diabetes was not determined to signi-
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