Subintimal Angioplasty: To Stent or Not to Stent?

From the Department of Cardiology, Marshfield Clinic, Wausau, Wisconsin and Saint Clares Hospital, Weston, Wisconsin. The authors report no conflicts of interest regarding the content herein. Manuscript submitted April 8, 2009 and accepted May 21, 2009. Address for correspondence: Aamir Hameed, MD, FACC, Oklahoma Cardiovascular Associates, 4221 S. Western Suite 4000, Oklahoma City, OK 73109. E-mail: aamirhameed@pol.net

_______________________________________________ ABSTRACT: The favored technique of peripheral subintimal angioplasty is to stent the subintimal channel, which usually requires long stents. However, there are no randomized trials comparing subintimal angioplasty with and without stenting. Our hypothesis is that after subintimal angioplasty, a newly created conduit should not be stented and stenting should only be reserved for bailout. Subintimal angioplasty is an effective and safe revascularization technique for patients with symptomatic claudication and critical limb ischemia. As the number of peripheral intervention procedures is increasing, experience with this technique is improving. The time has come for a randomized trial of subintimal angioplasty with and without stenting. Key words: Subintimal, angioplasty, peripheral

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J INVASIVE CARDIOL 2009;21:e154–e156 Case Presentation. A 71 year-old female with a history of diabetes mellitus, hypertension and hyperlipidemia was complaining of angina and claudication in the left leg. Workup of the patient revealed three-vessel coronary artery disease and carotid artery disease, with total occlusion of the right internal carotid artery (ICA). She also was found to have severe peripheral vascular disease, with high-grade stenosis of the left subclavian artery, high-grade stenosis of the right external iliac artery, a totally occluded right superficial femoral artery and high-grade stenosis of the left superficial femoral artery (SFA). She underwent three-vessel coronary artery bypass graft surgery (CABG). After CABG, we performed subintimal angioplasty of the right SFA and stenting of the right external iliac. The patient was discharged the next morning and is asymptomatic. Procedure. Using a contralateral approach through the left femoral artery, A 6 Fr Pinnacle Destination sheath (Terumo Medical Corp., Somerset, New Jersey) was advanced across the aortic bifurcation placed in the right common iliac artery. Using a 5 x 20 mm Agiltrac balloon (Abbott Vascular, Abbott Park, Illinois), the lesion in the right external iliac artery was dilated at 8 atm, but there remained 50% residual stenosis. Next, a 0.035 inch Glidewire (Boston Scientific Corp., Natick, Massachusetts) was advanced distally and we tried to cross the total occlusion. A 4 Fr Glide catheter (Terumo) was advanced on the back of the Glidewire. Dissection was carefully done in the subintimal plane, then the distal vessel was again entered with a Glidewire. The wire was pulled and the Glide catheter was advanced distally. A popliteal angiogram performed through the Glide catheter confirmed intraluminal positioning. Now a 0.035 inch J-tipped guidewire was advanced through the Glide catheter and parked in the popliteal artery and the Glide catheter was removed. Using a 4.0 x 100 mm Fox Plus balloon (Abbott Vascular) multiple inflations were performed starting distally all the way to the proximal end of the SFA. Angiography revealed nice reconstruction of the SFA from the ostium all the way into the popliteal artery. Since a good result was obtained after balloon angioplasty, we elected not to stent the newly created channel. We did not use a reentry device. A 7.0 x 60 mm Absolute stent (Guidant Corp., Indianapolis, Indiana) and a 8.0 x 40 mm Smart Stent (Cordis Corp., Miami Lakes, Florida) (both nitinol self-expanding stents) were used to stent the lesion in the right external iliac artery. Technique. Subintimal angioplasty is a modification of angioplasty where, instead of dilating the true lumen, a false lumen is created and dilated. It is used to cross long segments of chronic total occlusions. Proximal to the occlusion, then enters into the subintimal space (between the intima and media) and controlled dissection in the subintimal plane is performed distal to the occlusion. The wire is again entered into the true lumen. Multiple devices with and without Doppler ultrasound are available for reentry into the true lumen. Now the subintimal space is dilated with a balloon, plaque is shifted to the side and a new channel is created. This channel is then stented from the proximal to the distal end. Discussion. Subintimal angioplasty has been around for two decades, but the procedure has gained popularity in recent years.1 Initial studies reported a success rate of 74% and a complication rate of 16%, with 3% of complications requiring surgical intervention.2 Recent series have reported a success rate of 84–87% and a low complication rate of 4.7% without surgical intervention.3,4 Primary patency rates at 12 months are 45–55%.3,5,6 Limb salvage at 12 months is 80–90%.6 Limb salvage in patients with critical limb ischemia is 75% at 36 months,3 the secondary patency rate at 12 months is 71–76%3,5 and the secondary patency rate at 36 months is around 50%.6,3 Actuarial and hemodynamic patencies are 71% at 12 months and 58% at 36 months.7 Symptomatic patencies are 73% and 61% at 12 and 36 months, respectively.7 Infrainguinal subintimal angioplasty is an effective revascularization procedure and has been recommended as a first-line strategy for patients with critical limb ischemia.4 The favored technique is to stent the subintimal channel, which usually requires long stents. Our experience from coronary stenting is that restenosis is directly proportional to the length of the stent. Therefore, theoretically, it makes sense not to stent the newly created lumen. However, there are no randomized trials comparing subintimal angioplasty with and without stenting. A large retrospective review from a single center of selective stent use in subintimal angioplasty showed at two years that patients who received a stent are more likely to undergo open bypass surgery than those without a stent. Patients with prior lower extremity bypass surgery who received stents after subintimal angioplasty had worst outcomes compared to those without stents. The use of stents with a diameter ≤ 6 mm and indication of critical limb ischemia had worse results.8 In SFA angioplasty, stents > 6 mm are rarely used. Our hypothesis is that after subintimal angioplasty, newly created conduit should not be stented and stenting should only be reserved for bailout. The following are reasons for not using stents: 1) Native arteries are compliant conduits that constantly adjust to blood pressure and flow conditions (the Windkessel effect9,10 ); the use of long stents or Gortex grafts creates noncompliant conduits.11 2) Stents increase vascular resistance and impair flow;12 in coronary arteries this is not a major issue because the stent lengths used are small, however, after subintimal angioplasty in femoropopliteal arteries, multiple long stents are used. 3) Since this new channel is created between intimal and medial planes, it may enlarge over time, thus large balloons are not initially needed. 4) With aggressive statin and antiplatelet therapy, this conduit should remain free of atherosclerosis for an extended duration. The downside of this technique may be higher acute closure. If this occurs, it should not cause major complications since these are chronic total occlusions to begin with. The upside will be higher long-term patency rates and compliant vessels with a preserved hemodynamic profile. Conclusion. Subintimal angioplasty is an effective and safe revascularization technique for patients with symptomatic claudication and critical limb ischemia. As the number of peripheral intervention procedures is increasing, experience with this technique is improving. The time has come for a randomized trial of subintimal angioplasty with and without stenting.

2. McCarthy RJ, Neary W, Roobottom C, et al. Short-term results of femeropopliteal subintimal angioplasty. Br J Surg 2000;87:1361–1365.

3. Scott EC, Biuckians A, Light RE, et al. Subintimal angioplasty: Our experience in treatment of 506 infrainguinal arterial occlusions. J Vasc Surg 2008;48:878–884.

4. Tartri S, Zattoni L, Rizzati R, et al. Subintimal angioplasty as the first-choice revascularization technique for infrainguinal arterial occlusions in patients with critical limb ischemia. Ann Vasc Surg 2007;21:819–828.

5. Scott EC, Biuckians A, Light RE, et al. Subintimal angioplasty for the treatment of claudication and critical limb ischemia. J Vasc Surg 2007;46: 959–964.

6. Met R, Van Lienden KP, Koelemary MJ, et al. Subintimal angioplasty for peripheral arterial occlusive disease: A systemic review. Cardiovasc Intervent Radiol 2008;31:687–697.

7. London NJ, Srinivasan R, Naylor AR, et al. Subintimal angioplasty of femoropopliteal artery occlusions: The long term results. Eur J Vasc Surg 1994;8:148–155.

8. Schmieder GC, Richardson AI, Scott EC, et al. Selective stenting in subintimal angioplasty: Analysis of primary stent outcomes. J Vasc Surg 2008;48:1175–1180.

9. Frank O. Die Grundform des arteriellen pulses. Z Biol 2899;37:483–526.

10. Westerhof N, Lankhaar J-Willen, Westerhof BE. The arterial Windkessel. Med Biol Eng Comput DOI 10.1007/s11517-008-0359-2.

11. Vernhet H, Demaria R, Juan JM, et al. Changes in wall mechanics after endovascular stenting in the rabbit aorta. Am J Roentgenol 2001;176:803–807.

12. Richter Yoram, Edelman Elazer R. Cardiology is flow. Circulation 2006;113:2697–2682.