Transpedal Interventions for Critical Limb Ischemia

ABSTRACT: There is a growing prevalence of critical limb ischemia (CLI) with resulting complex patterns of tibial occlusive disease that represent unique challenges for interventionalists. Because patients with CLI have substantial comorbidity, endovascular therapy has emerged as the primary therapy in many cases, requiring novel and advanced techniques to achieve technical and clinical success. Standard techniques for crossing obstructive lesions fail in a substantial percentage of patients with CLI due to the presence of extensive arterial calcification and long-segment occlusions. Retrograde recanalization via fluoroscopic or ultrasound-guided puncture of reconstituted pedal vessels may allow lesion traversal in difficult cases, allowing primary retrograde revascularization or rendezvous techniques with subsequent antegrade intervention. This paper describes the rationale, techniques, and outcomes of transpedal interventions in patients with CLI.

VASCULAR DISEASE MANAGEMENT 2013:10(8):E152-E158 

Key words: peripheral vascular disease, critical limb ischemia, endovascular therapy

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Critical limb ischemia (CLI) represents the most advanced form of peripheral arterial occlusive disease (PAOD), manifested by pain at rest, focal or diffuse foot and ankle ulcerations, or gangrene. The rate of PAOD progression to CLI may approach 25%,¹ and these patients have a particularly poor prognosis. For patients with CLI, the natural clinical course over 1 year from the time of diagnosis has been estimated to follow the “rule of quarters,” with approximately one-quarter resolving, one-quarter having persistent CLI and ulceration, one-quarter having undergone major amputation, and one-quarter died.^2,3 Following amputation, nearly half of patients die within 1 year, and half of survivors never ambulate.⁴ These factors, combined with an epidemic increased prevalence of progression to CLI in elderly, diabetic, and chronic kidney disease patients, make CLI a sizeable and increasing burden on the healthcare system.^5,6

Historically, surgical^7-9 and endovascular^10-15 therapy for CLI have enabled approximately 80% “limb salvage.” Despite recognized risk factors, nearly 80% of patients who undergo major amputation fail to see a vascular specialist or undergo a vascular evaluation for potentially remediable disease.^16,17 Referrals for possible revascularization are often late, with resultant patterns of disease that are often challenging for reconstruction. Notably, in this population, there is a high proportion of long-segment and multivessel tibial occlusion, a paucity of well-formed collaterals, dense calcification, and poorly delineated pedal outflow channels. Consequently, traditional methods of antegrade recanalization fail in a high percentage of cases.¹⁸

Combined retrograde and antegrade interventions have historical precedent for femoropopliteal revascularization using the initially described “Bolia” technique.¹⁹ In these cases, the recanalized channel may be either intraluminal or subintimal, with eventual capture or snare retrieval of a retrogradely passed wire into an antegrade catheter, allowing wire rendezvous and subsequent antegrade intervention. Recent work by others^20-25 has demonstrated the ability to extend these “rendezvous” techniques to patients with complex patterns of tibial occlusive disease that either fail or are not amenable to other strategies.

Patient Selection

Transpedal revascularization may be used as either a primary or secondary strategy (Figure 1). More commonly, a secondary transpedal approach is utilized, after failed recanalization of occluded tibial segments using traditional or advanced antegrade catheter techniques. These patients typically have extensive calcification and long-segment arterial obstructions preventing successful intraluminal wire passage despite best attempts. This difficulty is compounded by the dense fibrocalcific nature of the proximal occlusive cap and the presence of numerous marginal collaterals at the occlusion margin through which wires preferentially direct. Due to the absence of dedicated distal tibial re-entry devices, if a subintimal path is created, spontaneous reentry into distal targets is required for interventional success. In our experience, this can be challenging, with inline flow restored to the foot in approximately 60% of subintimal cases; success rates are even lower when recanalizing an occluded posterior tibial artery due to difficulty advancing wires around the medial malleolus. In these instances, angiographically demonstrated patent distal calf or pedal arteries may be accessed directly with the goal of performing retrograde tibial recanalization.

Primary transpedal revascularization represents a novel interventional strategy for patients with unfavorable anatomy and an anticipated low likelihood of success using traditional techniques. In addition, a primary transpedal route may have benefit in allowing intraluminal revascularization if this is desired, such as when planning the use of drug-eluting balloons for treatment: due to the absence of marginal collaterals and a fibrous cap when passing wires cranially, maintaining a wire position within the true lumen may be facilitated. 

More recently, an intentional first-line transpedal approach has been advocated by Mustapha,²³ citing an ability to easily access the pedal vessels with ultrasound guidance, and describing treatment of both the anterior tibial and posterior tibial branches via a dorsalis pedis puncture. The rapid adoption of dissemination of these techniques will be enabled by the development of dedicated devices and training pathways, similar to what has evolved for transradial catheterization.²⁶

Tools

Transpedal revascularization is complex and time consuming. There are several key tools that interventionalists must be familiar with and have available in order to achieve successful revascularization. Prior to embarking on this journey one must allot the appropriate amount of time for the procedure; often, a second interventionalist may be needed for portions of the procedure.  

Transpedal access generally requires a handheld duplex ultrasound in order to visualize the tibiopedal vessels. Vascular access can be achieved by using a dedicated Micropuncture Pedal Access Set (Cook Medical). This kit comes with a 21-gauge, 4-cm echogenic needle, a 7-cm Micropuncture introducer, an 0.018˝ stainless steel mandril wire, and a hemostasis valve. The Check-Flo hemostasis valve (Cook Medical) can be attached to the 4 Fr introducer once access is achieved, allowing it to be used as an interventional introducer with a 2.9 Fr inner diameter. If a larger diameter introducer sheath is required, 4 Fr sheaths (and greater) are readily available. Vessel spasm can be prevented through the use of nitroglycerin and heparin.

Catheter, microcatheter, and wire choices are generally operator dependent (Table 1); however, in our lab we usually start with 2.6 Fr CXI Support Catheter or 4 Fr Kumpe Catheter (both from Cook Medical) to be our go-to catheters. The 2.6 Fr CXI Support Catheter (Cook Medical) fits nicely within the 4 Fr introducer/dilator from the Pedal Access Set and can be used as the main working catheter. Upsizing to a traditional 4 Fr sheath (e.g. in order to utilize atherectomy or other devices) requires placement of a 0.035˝ wire, which can be inserted through the 4 Fr micro access dilator.

In the setting of chronic total occlusion (CTO), initial wire choice is often focused on either hydrophilic or CTO-type wires. Our experience with the 0.014˝ Command wire (Abbott Vascular) and 0.014˝ Approach CTO wire (Cook Medical) have been favorable, however, there are many hydrophilic and total occlusion wires available on the market today. It may be worthwhile to stock several wires with shorter working lengths such as 130 cm for transpedal access cases. We have also used the 0.018˝ 70-degree Glidewire (Terumo Interventional Systems) with good result, particularly when retrograde recanalization results in subintimal wire passage, with the intent of achieving rendezvous in the subintimal space with an antegrade catheter to complete the case. Additionally, if a 4 Fr sheath and 4 Fr catheter are used, one can use a 0.035˝ glidewire for intraluminal or subintimal crossing (Terumo Interventional Systems).

When utilizing the SAFARI technique (subintimal antegrade flossing using antegrade and retrograde intervention), initial attempts are made to pass the retrograde wire directly into the lumen of the antegrade catheter. If this cannot be achieved, a re-entry device and snare may be needed. 

We typically use the Outback LTD Re-entry catheter (Cordis Corporation) in combination with either an 0.035˝ Expro Elite snare (Vascular Solutions) or 0.014˝ Micro Elite snare (Vascular Solutions). The re-entry catheter is typically used as the antegrade device, with the snared re-entry wire then pulled out through the pedal access for through-and-through control.

Technique

Pedal puncture

Transpedal access can be performed under direct ultrasound, fluoroscopic, and angiographic or roadmap guidance (Figure 2). A handheld duplex ultrasound can generally identify the desired pedal vessel for puncture. 

It is important to recognize the vessel in both long- and short-axis views to avoid venous puncture. Compression sonography helps identify the pulsatile artery from the adjacent vein, although Doppler interrogation may be used when arterial pressure is markedly diminished to ascertain which structure represents the pedal artery. When viewed in short axis, the artery is usually flanked by the accompanying vein on both sides (Figure 2A). In general, if wire passage is free and smooth, one should inject a small amount of contrast to confirm arterial vs venous access. In a heavily calcified pedal vessel one can perform the pedal puncture under direct fluoroscopic guidance (Figure 2B). 

For noncalcified puncture sites, roadmapping from the antegrade catheter may be performed to identify the artery. When patient motion is a problem, repeated angiographic injections during access can also be helpful to guide puncture (Figure 2C). To reduce radiation exposure to the operator’s hand during fluoroscopic or roadmap guided punctures, a remote needle access tool is distributed by Spectranetics, or surgical clamps can be used to guide the insertion needle.

Pedal access

If the micropuncture set 0.018˝ mandril wire freely passes into the artery, then the nested 3 Fr and 4 Fr dilators are inserted directly. However, if wire movement is restricted, or if the wire cannot be passed into the artery past the point of the solder connection between the coil tip and wire mandril, then the inner 3 Fr dilator may be inserted alone to allow contrast injection and assurance of successful arterial positioning. Densely calcified puncture sites pose a unique problem in which it may be difficult to advance even the 3 Fr inner dilator into the artery. This is particularly true if the puncture has been too vertical, with kinking of the wire during attempted dilator advancement. In these cases, a reinforced rigid 3 Fr dilator (Cook) may be tried, or the access needle itself may need to be carefully advanced in a rotary position to gain more purchase into the artery. The mandril wire can then be advanced until its soldered portion is within the artery, or a wire without a soldered transition (i.e. Roadrunner wire; Cook) may be tried. 

Once a secure position in the desired artery is confirmed, choose the appropriate working access. We will either use the 4 Fr introducer with Check-flo valve accompanied with the 2.6 Fr CXI support catheter as described above or choose a standard 4 Fr vascular sheath and 4 Fr catheter. If dense calcification or the absence of sufficient patent distal artery for wire exchange prevents the introduction of the initial 3 Fr or 4 Fr micropuncture dilator, a different or more distal arterial puncture may be necessary.

Antegrade crossing and catheter/wire positioning

After failed recanalization of occluded tibial segments (using standard and advanced techniques), the antegrade wire or catheter should be left in place as a target for re-entry from the retrograde access. One may position the antegrade catheter or wire in the most distal aspect of the true lumen or in a distal subintimal space that would be a good location for re-entry via rendezvous technique (Figure 3).

Retrograde vessel crossing and catheter positioning

From the tibial access, using a wire and catheter retrograde crossing of the desired tibial vessel is performed using a standard technique. One should be careful to maintain intraluminal passage through the vessel in order to re-enter more proximally. If one is able to secure intraluminal passage through the proximal occluded segment, it is possible to either directly cannulate the antegrade catheter or sheath or use a snare to pull the wire from the retrograde sheath through the antegrade sheath. Dedicated catheters are now available to ease the direct cannulation technique (Quick-Cross Capture Guidewire Retriever; Spectranetics). 

Re-entry device, snare positioning, deployment and “flossing”

If re-entry from the retrograde sheath fails, the re-entry and snare technique is useful to gain “through and through” luminal access. From the antegrade sheath, position the Outback catheter as distally as possible in the subintimal plane (usually at the point of failed re-entry) (Figure 4A). From the retrograde sheath, advance a catheter and snare as proximally as possible. Deploy the Outback needle and advance the wire from the Outback catheter into the snare and pull the snare through the retrograde sheath (Figure 4B). Fluoroscopy in multiple planes helps to align the puncture towards the snare and reduce the number of passes needed for success. If there is particularly dense calcification at the initially selected re-entry site, then a more proximal or distal position should be tried. 

Once the wire is pulled through the retrograde sheath, clamp the wire and remove the Outback from the antegrade sheath. The wire is now “flossed” and one may proceed in the usual manner to revascularize the disease segments. Angioplasty and stenting as needed ensues in the normal manner using this wire as your working wire.

Hemostasis

After the completion of intervention, hemostasis is generally achieved by manual compression with a hemostatic pad; we often use the TipStop bandage (Gambro) for this purpose. Balloon-assisted hemostasis may also be achieved by inflating an angioplasty balloon at low pressure across the puncture site for 3 to 5 minutes. Finally, for peroneal punctures, inflation of an external blood pressure cuff over the calf can be performed for several minutes.

Clinical Data

The reported clinical experience with transpedal tibial intervention involves predominantly case reports and small series.^10-15,20-25 In the original series by Spinosa et al, procedural success was accomplished with the SAFARI technique in 12 patients using anterior tibial-dorsalis pedis or posterior tibial access.¹⁰ One-year patency in this series (including transpopliteal SAFARI procedures for femoropopliteal occlusions) occurred in 58%.¹⁰ Gandini et al reported their experience using the SAFARI technique in four patients with nonhealing wounds and femoropopliteal occlusions.¹¹ Antegrade access was obtained via the ipsilateral common femoral artery, and retrograde puncture through either the distal anterior tibial or posterior tibial artery, with subintimal wire snaring at the popliteal level and retrieval through the femoral access to allow subsequent procedure completion. All patients had wound healing by 3 months, and there were no pedal puncture site complications. Paleno and Manzo described direct puncture of the first dorsal metatarsal artery or pedal loop for retrograde catheter insertion in patients in whom the distal anterior tibial, dorsalis pedis, or posterior tibial arteries were not accessible.¹⁵ In this report, recanalization and intervention via the distal access was successfully achieved in 24 of 28 patients (86%). Restoration of straight line flow after intervention resulted in a 71% 6-month limb salvage rate; amputation avoidance was not achieved in any of the cases in which transpedal puncture could not be performed. Similar success rates have been described by Rogers et al, with 85% of 13 patients undergoing favorable revascularization using combined antegrade and pedal approaches.²² More recently, direct retrograde atherectomy techniques have been applied as a primary treatment strategy.^23,25 

Conclusion

Transpedal interventions represent a unique and potentially limb preserving recanalization and revascularization technique in patients with CLI and advanced tibial occlusive disease. There will potentially be an increasing prevalence of patients with complex patterns of infrapopliteal atherosclerotic disease, and familiarity with the SAFARI technique will be of growing importance for interventionalists treating CLI patients.

Editor’s Note: Disclosure: The authors have completed and returned the ICMJE Form for Disclosure of Potential Conflicts of Interest. The authors report no conflicts of interest regarding the content herein. 

Manuscript received April 30, 2013; final version accepted May 20, 2013.

Address for correspondence: John Rundback, MD, FAHA, FSVM, FSIR, Holy Name Medical Center, Interventional Institute, Teaneck, NJ, 07666, USA. Email: jrundback@airsllp.com

References

1. Aquino R, Johnnides C, Makaroun M, et al. Natural history of claudication: Long-term serial follow-up study of 1244 claudicants. J Vasc Surg. 2001;34(6): 962–970.
2. Norgren L, Hiatt WR, Dormandy JA, et al. Inter-society consensus for the management of peripheral arterial disease (TASC II).  Eur J Vasc Endovasc Surg. 2007;33(Suppl 1):S1-75. 
3. Taute BM, Thommes S, Taute R, Rapmund I, Lindner K, Podhaisky H. Long-term outcome of patients with mild intermittent claudication under secondary prevention. Vasa. 2009;38(4):346-349.
4. Aulivola B, Hile CN, Hamdan AD, et al. Major lower extremity amputation: outcome of a modern series. Arch Surg. 2004;139(4):395-399.
5. Barshes NR, Chambers JD, Cohen J, Belkin M, Model To Optimize Healthcare Value in Ischemic Extremities 1 (MOVIE) Study Collaborators. Cost-effectiveness in the contemporary management of critical limb ischemia with tissue loss. J Vasc Surg. 2012;56(4):1015-1024.
6. Henry AJ, Hevelone ND, Hawkins AT, Watkins MT, Belkin M, Nguyen LL. Factors predicting resource utilization and survival after major amputation. J Vasc Surg. 2013;57(3):784-790.
7. Biancari F, Salenius JP, Heikkinen M, Luther M, Ylönen K, Lepäntalo M. Risk-scoring method for prediction of 30-day postoperative outcome after infrainguinal surgical revascularization for critical lower-limb ischemia: a Finnvasc registry study. World J Surg. 2007;31(1):217-225.
8. Conte MS, Bandyk DF, Clowes AW, et al. Results of PREVENT III: a multicenter, randomized trial of edifoligide for the prevention of vein graft failure in lower extremity bypass surgery. J Vasc Surg. 2006;43(4):742-751.
9. Adam DJ, Beard JD, Cleveland T, et al. Bypass versus angioplasty in severe ischaemia of the leg (BASIL): multicentre, randomised controlled trial. Lancet. 2005;366(9501):1925–1934.
10. Spinosa DJ, Harthun NL, Bissonette EA, et al. Subintimal arterial flossing with antegtrade–retrograde intervention (SAFARI) for subintimal recanalization to treat chronic critical limb ischemia. J Vasc Interv Radiol. 2005;16(1):37-44.
11. Gandini R, Pipitone V, Stefanini M, et al. The ‘‘Safari’’ technique to perform difficult subintimal infragenicular vessels. Cardiovasc Interv Radiol. 2007;30(3):469-473.
12. Fusaro M, Tashani A, Mollicheli N, Medda M, Inglese L, Biondi-Zoccai GG. Retrograde pedal artery access for below-the-knee percutaneous revascularisation. J Cardiovasc Med (Hagerstown). 2007;8(3):216-218.
13. Alqahtani S, Kandeel AY, Rolf T, Frederic G, Qanadli SD. Case report:  an unusual combined retrograde and antegrade transpedal subintimal recanalization of the infrainguinal arteries. J Vasc Interv Radiol. 2012;23(10):1325-1329.
14. Ruzsa Z, Pinter L, Kolvenbach R. Retrograde transpedal stenting of the tibioperoneal trunk in critical limb ischemia. Catheteriz Cardiovasc Intervent. 2012;80(7):1105-1111.
15. Palena LM, Manzi M. Extreme below-the-knee interventions: retrograde transmetatarsal or transplantar arch access for foot salvage in challenging cases of critical limb ischemia. J Endovasc Ther. 2012;19(6):805-811.
16. Met R, Koelemay MJ, Bipat S, Legemate DA, van Lienden KP, Reekers JA. Always contact a vascular interventional specialist before amputating a patient with critical limb ischemia. Cardiovasc Intervent Radiol. 2010;33(3):469-474.
17. Rhim B, Harkless L. Prevention: can we stop problems before they arise? Semin Vasc Surg. 2012;25(2):122-128.
18. Vraux H, Hammer F, Verhelst R, Goffette P, Vandeleene B. Subintimal angioplasty of tibial vessel occlusions in the treatment of critical limb ischemia: Mid-term results. Eur J Vasc Endovasc Surg. 2000;20(5):441-446.
19. Bolia A, Sayer RD, Thompson MM, Bell PR. Subintimal and intraluminal recanalization of occluded crural arteries by percutaneous balloon angioplasty. Eur J Vasc Surg. 1994;8(2):214-219.
20. Botti CF Jr, Ansel GM, Silver MJ, Barker BJ, South S. Percutaneous retrograde tibial access in limb salvage. J Endovasc Ther. 2003;10(3):614–618.
21. Manzi M, Palena LM. Retrograde percutaneous transmetatarsal artery access: new approach for extreme revascularization in challenging cases of critical limb ischemia. Cardiovasc Intervent Radiol. 2013;36(2):554–557.
22. Rogers RK, Dattilo PB, Garcia JA, Tsai T, Casserly IP. Retrograde approach to recanalization of complex tibial disease. Catheter Cardiovasc Interv. 2011;77(6):915-925.
23. Mustapha JA, Saab F, McGoff T, Heaney C. TAMI technique: tibiopedal arterial minimally invasive retrograde revascularization. Available at https://bmctoday.net/evtoday/2013/01/article.asp?f=tami-technique-tibiopedal-arterial-minimally-invasive-retrograde-revascularization.
24. Graziani L, Morelli LG. Combined retrograde–antegrade arterial recanalization through collateral vessels: redefinition of the technique for below-the-knee arteries. Cardiovasc Intervent Radiol. 2011;34(Suppl 2):S78–S82.
25. An HM, Kang WY, Kim YH, et al. Below the knee intervention using multidisciplinary methods including an antegrade, retrograde approach without the use of a sheath but with a plaque excision device.  Korean Cir J. 2012;42(2):125-128.