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Subintimal Angioplasty 121
Contralateral Retrograde Approach
This is useful in large patients where antegrade access over the femoral head is
compromised due to the bulk of abdominal wall fat.
• With this approach, controlled advance of the guidewire is more difficult. Even if
the wire can be advanced relatively easily through the occlusion, it can be difficult
to follow the wire with the catheter.
• To overcome these potential problems, the use of a balloon catheter as a
predilating catheter is recommended.
• Difficulties are increased if there is tortuous iliac artery anatomy, or there is a
steeply angled aortic bifurcation.
• Sheaths specifically designed for “cross-over” may be useful.
• Re-entry catheters can still be used from this approach.
Popliteal Artery Approach
This access is useful if antegrade access fails and if there is a true “flush” occlusion
of the SFA origin and it is not possible to know where the SFA origin is.
• A disease-free segment of above knee popliteal artery is required.
• The patient must be capable of lying prone.
• The puncture should be ultrasound guided to avoid the partially overlying
popliteal vein.
Subintimal Angioplasty for Below Knee Occlusions
The basic technique is similar to that for the SFA and popliteal artery.
• If the occlusion starts in the popliteal artery, decide which of the crural arteries
are the best vessels to recanalize.
• The looped guidewire has a tendency to follow the peroneal or the posterior tibial
artery, so if you want to access the anterior tibial artery, an angled-tip catheter is
usually required.
• A J tip “semi- stiff” hydrophilic guidewire (Terumo) is a very useful wire in the
crural vessels, since it can be difficult to reform a loop in an angled-tip wire in
these small vessels.
• It can be difficult to make a catheter track over the wire through long crural vessel
occlusions, so it is often better to use a small (3 mm) balloon, which may need to
be inflated and deflated to advance it distally.
• Re-entry catheters are not appropriate in these arteries but fortunately re-entry to
the lumen is rarely a problem through the thin intima of these vessels.
122 G. Fishwick
• As with SFA recanalization, re-entry to the lumen is only usually achieved where
the artery becomes relatively disease free, since it is at this location that the intima
becomes thin enabling re-entry.
Subintimal Angioplasty in Iliac Artery Occlusions
Intraluminal angioplasty and stenting via an ipsilateral retrograde approach is the
preferred technique for iliac artery occlusions.
Where the occlusion cannot be crossed through the lumen (i.e., intraluminal
recanalization), subintimal recanalization is appropriate.
• This can be achieved from a contralateral, ipsilateral, or a combined approach.
• From a contralateral approach, a wire is advanced to the occlusion, supported by
a catheter.
b
The wire is advanced into the occlusion and will either cross the lesion via the
lumen (in which case the lesion can be treated by angioplasty and stented),
or it will dissect through the subintimal space, will form a loop and can be
advanced subintimally.
b
If the wire does not break back into the lumen immediately below the
occlusion, the length of the dissection can be controlled by creating a
dissection from below using an ipsilateral retrograde approach. The dis-
section plane is usually (though not invariably) the same from below and
above.
b
Once a wire is established back into the lumen from either below or above,
the occlusion can be treated by angioplasty.
• With the ipsilateral approach, the catheter and guidewire are advanced subinti-
mally retrogradely, with the hope that the wire will re-enter the lumen in the
patent iliac artery above the occlusion, or at the aortic bifurcation if the occlusion
extends to the common iliac artery origin
b
However, it is not possible to predict the location of re-entry. Although re-
entry at the aortic bifurcation occurs sometimes, the wire often continues to
dissect up the aorta, which usually signals a failure of this approach, unless
the vessel is also recanalized from above (see above).
• An alternative approach when using an ipsilateral retrograde approach is to use
a re-entry catheter when the catheter and wire are located in a dissection and to
puncture the intima above the dissection to re-enter the lumen.
• If the ipsilateral retrograde approach is used, it is still necessary to have access
from the contralateral femoral artery to image the re-entry point.
Subintimal Angioplasty 123
Performing the Angioplasty
• When the wire tip has re-entered the vessel lumen below the occlusion, the
catheter is exchanged for a balloon of appropriate size (usually 4–6-mm diameter
in the SFA/popliteal segment).
• Long balloon lengths are best (10–12 cm).
• Rapid inflation/deflation is performed with a Kimal inflation syringe along the
length of the subintimal channel.
• Taking care not to lose the wire position, the entire length of the occlusion is
balloon angioplastied once or twice.
Endpoint
• The recanalized segment is examined by angiography for
b
Patency − often ribbon like and spiraling (Fig. 4).
Fig. 4 Patent, spiraling
post-angioplasty channel
124 G. Fishwick
b
Rapid flow − the main determinant of procedure completion.
b
Patent run-off below the occlusion.
b
Stents are occasionally required at the proximal and distal ends of the subinti-
mal channel to achieve rapid flow. Specific self-expanding SFA stents are now
available.
• The foot should also be examined to confirm improved capillary return.
• If the above three angiographic features are present and the foot is improved, the
procedure is deemed a success.
Immediate Post-procedure Care
• The groin puncture site is closed either with a closure device (if appropriate), or
by manual pressure.
• The duration of prescribed bed rest will depend on whether or not a closure device
is used.
• There is no specific post-procedure medication.
• Medication stopped prior to angioplasty can be restarted as appropriate.
Follow-Up and Post-procedure Care
• Patients are followed up initially either in the interventional radiology clinic or in
the vascular surgical clinic.
• If the patients’ symptoms resolve, they can be discharged back to their primary
care physician.
• If symptoms recur or do not respond to the procedure, they should be assessed by
duplex ultrasound to evaluate whether the lesions have recurred.
Results
These are technically difficult procedures with an approximate 10% failure rate to
achieve the desired endpoint. Technical failure may be due to
• Failure to create a dissection channel (usually due to heavy calcification in the
vessel walls).
• Perforation of the channel with failure to bypass the perforation.
• The channel is created, but there is poor flow or thrombosis in the channel.
• Thrombus in the channel can be aspirated via a wide-bore catheter.
• An underlying focal abnormality causing poor flow and thrombosis may need
“spot” stenting, e.g., a flow-limiting dissection flap, or more commonly a densely
calcified segment of vessel wall.
Subintimal Angioplasty 125
Fig. 5 Perforation in
popliteal segment excluded
by new dissection
• Perforation in the channel can sometimes be bypassed by recreating a new
dissection channel (Fig. 5).
• Around 15% of patients undergoing this procedure fail to gain relief from CLI
and its symptoms, and subsequently require bypass surgery.
• Of the procedures undertaken, only 50% of the femoropopliteal segment channels
and 40% of the channels extending into the tibial arteries are patent at 2 years.
b
The fact that only 15% of patients require bypass surgery (including initial
technical failures) means that even with this relatively low 2-year patency rate,
there is considerable relief from CLI even for many of the patients in whom
the recanalized vessel subsequently reoccludes.
• Long-term patency is inversely related to the length of the occlusion and is
directly related to the number of patent run-off vessels.
• Bypass surgery is rarely compromised by prior subintimal angioplasty.
126 G. Fishwick
Alternative Therapies
The alternative to subintimal angioplasty in these patients is bypass surgery.
• Aortofemoral bypass
• Iliofemoral bypass
• Ilio- or femorofemoral cross-over
• Axillofemoral bypass
• Femoropopliteal bypass
• Femorodistal. bypass
In some cases bypass surgery is relatively straightforward, and in many centers it
is the preferred option. However, in centers offering subintimal angioplasty, bypass
surgery is generally reserved for failed angioplasty.
Where there is significant (particularly eccentric) common femoral artery dis-
ease, common femoral endarterectomy is the preferred treatment. This can be done
in conjunction with subintimal angioplasty as a combined procedure to try to avoid
more extensive bypass surgery.
Complications of Subintimal Angioplasty
Distal Embolization
• The most significant complication of subintimal angioplasty.
• This requires aspiration, usually via a 7 or 8F catheter, if the embolus is in the
popliteal artery, or via a 5 or 6F catheter if the embolus is in the crural arteries.
b
The catheter is directed into the embolus and aspiration is performed by
suction with a 50-mL Luer-lock syringe.
b
The embolus is usually sucked onto the catheter tip rather than aspirated up
the catheter lumen, in which case it is withdrawn into the sheath on the end of
the catheter (while still applying suction).
b
It is necessary to have a removable cap on the sheath as emboli will rarely
pass through the hemostatic valve and are usually trapped within it.
• Most emboli can be removed by aspiration thrombectomy, although occasionally
large emboli may require surgical embolectomy for their extraction.
Vessel Perforation
This is usually a complication of the creation of the dissection caused by the wire,
rather than a sequel of balloon dilaton of a channel, which has been successfully
created.
Subintimal Angioplasty 127
• The successful creation of a new dissection channel usually excludes the
perforation, in which case no further treatment is necessary.
• Failure to create a new channel usually leads to termination of the procedure.
• Most perforations are self-limiting and require no further treatment.
• Occasionally, vessel perforation is associated with persistent pain and continued
extravasation. In this situation, the channel to the perforation may need to be
occluded either with gelfoam or by coil embolization.
• Perforation of a successfully created dissection channel due to PTA is very
uncommon. Similar to the previous section, it is usually self-limiting. Rarely,
a covered stent is required.
• Perforation into a vein creating an A−V fistula occurs occasionally. This is
usually around the trifurcation area and is managed in the same way as other
perforations.
• A perforation can be recognized as it occurs, due to deviation and expansion of
the loop of the wire.
Other Complications
More general complications, not related to the subintimal technique but to the
arterial puncture and the use of contrast agents, should be managed appropriately.
The most significant complication related to the puncture site, which must be
recognized and treated, is hemorrhage from a high puncture.
• If the femoral artery is punctured above the midpoint of the femoral head, hemor-
rhage may track superiorly to the retro-peritoneum behind the inguinal ligament,
rather than presenting as hematoma in the groin.
• This should be suspected in any patient who becomes hypotensive following
antegrade femoral puncture.
• It is a potentially fatal complication if it goes unrecognized.
• Puncture of the femoral artery below the midpoint of the femoral head avoids this
complication.
Key Points
• Use a careful and consistent puncture technique.
• Create the dissection precisely and proximal to the occlusion.
• Identify the area where re-entry to the lumen is anticipated.
• Be bold and extend the dissection to the level of the normal artery.
• Work quickly, but without rushing. This reduces the likelihood of throm-
bosis of the dissection channel.
• Be prepared for, recognize, and treat appropriately any complications that
occur.
• There is usually a surgical option − do not compromise this option.
128 G. Fishwick
Suggested Further Reading
1. Abdelsalam H, Markose G, Bolia A. Revascularization strategies in below the knee interven-
tions. J Cardiovasc Surg (Torino) 2008 Apr; 49(2):187–91. Review.
2. Ascher E, Hingorani A. Subintimal angioplasty. J Cardiovasc Surg (Torino) 2007 Feb; 48(1):
45–8. Review.
3. Bolia A, Miles KA, Brennan J, Bell PR. Percutaneous transluminal angioplasty of occlusions
of the femoral and popliteal arteries by subintimal dissection. Cardiovasc Intervent Radiol 1990
Dec; 13(6): 357–63
4. Bolia A. Subintimal angioplasty in lower limb ischaemia. J Cardiovasc Surg (Torino) 2005
Aug; 46(4): 385–94. Review.
5. Met R, Van Lienden KP, Koelemay MJ, Bipat S, Legemate DA, Reekers JA. Subintimal angio-
plasty for peripheral arterial occlusive disease: a systematic review. Cardiovasc Intervent Radiol
2008 Jul−Aug; 31(4): 687–97. Epub 2008 Apr 15. Review.
6. Reekers JA, Bolia A. Percutaneous intentional extraluminal (subintimal) recanalization: how to
do it yourself. Eur J Radiol 1998 Oct; 28(3): 192–8.
7. Treiman GS. Subintimal angioplasty for infrainguinal occlusive disease. Surg Clin North Am
2004 Oct; 84(5): 1365–80, viii. Review.
Infrapopliteal Angioplasty and Stenting
Marc Sapoval, Olivier Pellerin, and Laurent Bellmann
Clinical Features
• Only patients with critical limb ischemia (CLI) should undergo angioplasty or
stenting distal to the popliteal artery.
• CLI is defined as arterial ulceration, gangrene, or rest pain of longer duration than
2 weeks, with hemodynamic evidence of arterial disease (distal blood pressure
<50 mmHg or a toe pressure <30 mmHg).
• This subgroup of patients is at a high risk of amputation if revascularization is
not performed within a short time period.
• CLI is not acute limb ischemia where immediate limb loss is a major risk.
• Risk factors for CLI include smoking, renal failure, and diabetes mellitus.
Diabetic patients have a high incidence of distal arterial disease.
Diagnostic Evaluation
Clinical
• Regarding CLI, the Rutherford classification differentiates between rest pain,
minor ulcer, and major ulcer.
• Careful vascular examination is required with examination of the foot especially
in diabetic patients.
• Arterial ulcers are painful, and usually occur at the level of the ankle, often at
the lateral malleolus. The underlying skin i s dry and cold, as opposed to venous
ulcers.
• Wound infection and cellulitis in patients with CLI may cause a rapid deteriora-
tion in the distal circulation, which may lead to amputation, especially in diabetic
patients.
129
R.A. Morgan, E. Walser (eds.), Handbook of Angioplasty and Stenting Procedures,
Techniques in Interventional Radiology, DOI 10.1007/978-1-84800-399-6_11,
C
Springer-Verlag London Limited 2010
130 M. Sapoval et al.
Laboratory
• Standard preoperative biochemical and hematological workup is necessary. The
serum ESR and CRP, in addition to the WBC, are important to rule out possible
underlying infection.
• The serum creatinine (and in some patients creatinine clearance) should be
assessed, in case measures are required to prevent contrast-mediated nephro-
toxicity. Such measures include intravenous hydration and carbon dioxide
angiography.
• The ABI and toes pressures are useful non-invasive tests for peripheral arterial
disease. A normal ABI is >0.9. If the ABI is >1.2, the arteries are deemed to
be non-compressible due to the presence of calcification. This is often the case
in diabetic patients, and in such patients, infrapopliteal arterial lesions should be
suspected.
Imaging
The aim of imaging is to define the anatomy, to indicate whether the circulation
can be improved by intervention, either endovascular or surgical, and to define the
locations which require treatment.
• Conventional DSA remains the best imaging method to define the infrapopliteal
and pedal vessels in patients with CLI, to enable the optimal strategy for
revascularization.
• All three infrapopliteal run-off vessels should be analyzed carefully, as well as
the dorsalis pedis artery, the plantar arteries, and the plantar arch.
• Duplex in very experienced hands can be accurate for the assessment of the
infrapopliteal vessels.
• MRA in experienced hands can visualize the pedal arteries and the infrapopliteal
vessels. However, a poorly performed MRA often provides negligible useful
information.
• CTA is less useful in CLI, because there is often heavy calcification in the
infrapopliteal vessels.
Indications
• The presence of critical limb ischemia, i.e., rest pain, ulceration, or gangrene
indicates intervention.