Modified Culotte Stenting Technique for Bifurcation Lesions: The Cross-Stenting Technique

ABSTRACT: Despite recent technical advances, the treatment of bifurcation lesions with percutaneous coronary intervention (PCI) remains a challenge. In daily practice, several bifurcation stenting techniques are now being used. However, even in the DES era, many of these techniques are associated with a high incidence of in-stent restenosis. As a result, the debate regarding the optimal treatment of bifurcation lesions remains controversial. This article describes the “cross-stent” technique, a newly modified culotte stent technique for bifurcation lesions, which alleviates several technical limitations associated with previous two-stent techniques. J INVASIVE CARDIOL 2010;22:243–246 Key words: bifurcation lesion, drug-eluting stent, angioplasty The drug-eluting stent (DES) is commonly utilized in the clinical field to aggressively treat bifurcation lesions. However, bifurcation stenting using the two-stent technique (including the T-stent, ¹ simultaneous kissing stent, ² culotte stent, ³ crush stent, ⁴ etc.) is still controversial because the outcomes are not shown to be superior to the traditional one-stent strategy. ^5–7 In particular, the rate of restenosis at the side branch (SB) ostium remains high due to several technical limitations including inadequate coverage of the carina, stent distortion and multi-stent layering. ⁸ However, it seems that about 60% of all bifurcation cases demonstrate disease involvement with the SB ostium, and the two-stent technique should be considered in true bifurcation lesions according to the MEDINA classification (1, 1, 1), (1, 0, 1) or (0, 1, 1). ⁹ Therefore, further improvements in the two-stent technique are necessary. We herein describe the “cross-stent” technique, a newly modified traditional culotte stent technique for bifurcation lesions, which is considered to minimize several of the technical limitations described above.

Procedure

A schematic illustration of the cross-stent technique is shown in Figures 1 and 2. ¹ To avoid creating a gap between the main branch (MB) stent and the SB stent, the proximal edge of the SB stent is adjacent to the proximal carina (Figure 1A, arrow). After deploying the stent, the stent balloon is pulled back slightly and then fully expanded. At this time, the opposite edge of the SB stent may protrude 1 or 2 struts into the MB (Figure 1A, arrowhead). ² The wire in the SB is pulled back carefully and then reinserted into the MB through the protruding SB stent strut (Figure 1B, Figure 2A). ³ After dilation of the SB stent strut (Figure 2B), the MB stent is deployed through the dilated SB strut (Figures 1C, 1D and 2C, 2D). After pulling back and re-crossing the wire (which was placed into the MB at the beginning of the procedure) into the SB through the MB stent strut, a simultaneous balloon dilation is performed (Figures 1E and 2E), and the cross-stent is completed (Figures 1E and 2E). Left main trunk bifurcation (Case 1). A 75-year-old male was admitted to our hospital with recurrent chest pain that began in July 2008 after physical exertion. He had undergone percutaneous coronary intervention (PCI) for exertion-induced angina pectoris. A 3.0 mm x 20 mm paclitaxel-eluting stent (PES) had been implanted in the ostium of the left anterior descending artery (LAD) in August 2007 and a 2.5 mm x 28 mm sirolimus-eluting stent (SES) had been implanted in the mid-left circumflex artery (LCx) in November 2007. Coronary angiography revealed a severe de novo lesion in the LCx and moderate in-stent restenosis of the previous PES at the ostial LAD (MEDINA 0, 1, 1) (Figure 3A). PCI was performed at the left main trunk (LMT) bifurcation. A 7 Fr BL 3.5 guiding catheter (Mach1, Boston Scientific, Natick, Massachusetts) was inserted via the right femoral artery. After advancing the guidewires into both the LAD and LCx, predilatation of the LCx lesion was performed with a 3.0 mm balloon (Apex, Boston Scientific). A 3.0 mm x 16 mm PES was subsequently deployed into the LCx lesion at 18 atmospheres (atm), placing the proximal stent edge to the proximal carina (Figure 3B, arrow). After dilatation of the PES, the wire in the LCx was carefully pulled back and then inserted into the LAD through the protruding stent strut. After dilatation of the stent strut with a 3.0 mm balloon, a 3.5 mm x 18 mm SES was deployed at 20 atm in the proximal LAD lesion to the LMT through the dilated PES strut (Figure 3C). After re-crossing the wire into the LCx, simultaneous balloon dilatation was performed with a 3.5 mm balloon in the LAD and a 3.0 mm balloon in the LCx at 12 atm (Figure 3D). This completed the cross-stenting and the final coronary angiogram showed an excellent outcome (Figure 3E). The patient’s chest symptoms subsided, and the follow-up coronary angiogram at 8 months revealed no visible stent restenosis in either the LAD or LCx ostium (Figure 3F). LAD-diagonal bifurcation (Case 2). A 71-year-old male was admitted with exertion-induced chest pain in October 2008. Coronary angiography revealed severe de novo bifurcated lesions of the mid-LAD and first diagonal branch (D1) (MEDINA 0, 1, 1) (Figure 4A), and PCI was subsequently performed. A 6.5 Fr BLK 3.5 guiding catheter (Copernicus, Medikit Co., Japan) was used via the right radial artery. After crossing the guidewire to both the LAD and D1, pre-dilatation of both lesions was performed with a 2.5 mm balloon (Ottimo Rosso, Japan Lifeline). Then, a 2.5 mm x 20 mm PES was deployed into the D1 lesion at 18 atm placing the proximal stent edge to the proximal carina (Figure 4B, arrow). After dilatation of the PES, the wire in the D1 was carefully pulled back and then inserted into the distal LAD through the protruding stent strut. After dilatation with the 2.5 mm balloon, a 3.0 mm x 23 mm SES was deployed at 20 atm to cover the LAD lesion through the dilated PES strut (Figure 4C). An intravascular ultrasound (IVUS) image is shown in Figure 5. The dilated PES strut is observed around the IVUS catheter (Figure 5, arrow head). This finding confirms that the wire re-crossed into the LAD through the protruding PES strut. After simultaneous balloon dilatation was performed with a 3.0 mm balloon at the LAD and a 2.5 mm balloon at D1 at 12 atm (Figure 4D), cross-stenting is completed, and the final coronary angiography demonstrates excellent results (Figure 4E). The follow-up coronary angiography at 8 months revealed no visible stent restenosis in either branch (Figure 4F).

Discussion

There is still a great deal of debate regarding strategies of the two-stent technique for bifurcation lesions, because of their numerous technical problems and higher in-stent restenosis rate, especially in the SB ostium. There are several potential mechanisms for in-stent restenosis after bifurcation stenting, including inadequate coverage of the carina, excess stent coverage of the vessel wall, free stent struts in the bifurcation and distortion of the original vasculature. ⁸ Currently, T-stenting, crush-stenting, culotte stenting and simultaneous kissing stents are utilized as two-stent techniques for bifurcation lesions. ^10,11 However, several technical problems are associated with each of these strategies. In the T-stent technique, gaps between both the MB and SB stents may occur at the proximal bifurcation carina despite precise stent placement. This results in incomplete coverage of the ostium of the SB. ¹⁰ In the crush-stenting technique, gaps between stents also occur due to the distortions of the crushed stent at the distal carina. ¹² A double layer of stent strut is always present at the SB ostium, leading to a suboptimal result at the SB ostium. In addition, there are three layers of metal in the proximal MB, which may lead to excess drug elution. ¹⁰ In the simultaneous kissing stent technique, the free metal (strut) wall is established in the MB and inadequate stent apposition results in a large gap. ¹⁰ Also, the opening of the stent may be limited by the degree of the bifurcation angle. ¹³ Recently, the culotte stent technique has been revisited as the treatment of true bifurcation lesions because of the excellent scaffolding results and the ability to utilize this technique in all bifurcation angles. Furthermore, it may provide near-perfect coverage of the SB ostium. ¹⁰ Recent reports demonstrate a lower restenosis rate or a lower target lesion revascularization rate associated with this technique compared to T-stenting or crush-stenting. ¹⁴ On the other hand, a large amount of metal overlap in the proximal MB is thought to be a disadvantage of this technique. ^10,15 In addition, the “napkin-ring” formation in each branch ostium is considered a disadvantage, especially for a closed-cell stent such as an SES. ¹⁵

“Cross-Stenting” Technique

The cross-stenting technique is conceptualized as a “minimum” overlap of the traditional culotte stent technique. In culotte stenting, there is concern about increased stent thrombosis or increased drug effect due to excess stent overlap. In contrast, our cross-stenting reduces the risk of stent thrombosis because the stent overlap is kept to a minimum of one or two struts (Figures 1F and 2F) in the MB. As a result, stent distortion and distortion of the shape of the carina are minimized even when there is an acute take-off of the SB from the MB. This decreases the potential for flow disturbance and clinical restenosis. This technique also provides virtually perfect coverage of the diseased area, with no apparent gap. In addition, there is no technical or procedural complexity associated with this stenting technique. For these reasons, this cross-stenting technique is thought to be more advantageous than the traditional culotte stenting technique. This technique is used for true bifurcation lesions including the MEDINA classifications (1,1,1), (0,1,1) and (1,0,1). When performing this technique, it is important to sufficiently expand the MB stent. Therefore, the open-cell DES designs, including Taxus Liberté (Boston Scientific; stent strut opens up to 3.6 mm), Endeavor (Medtronic, Inc., Santa Rosa, California; strut opens up to 6.4 mm), Xience/Promus (Abbott Vascular, Santa Rosa, California/Boston Scientific; strut opens up to 4.4 mm) are useful as SB stents.

Procedural Limitations

In the cross-stenting technique, since the SB stent is deployed first, there is concern regarding plaque shift and jailing the MB. However, this can be reduced by sufficient predilatation. In addition, technically, re-crossing the SB wire into the MB is easier since the wire in the MB acts as a landmark while re-crossing into the MB. We have now treated more than 20 cases using this technique and there have been no procedural failures. In our experience, the SES is aggressively used in the MB because of its high reliability and the PES is used in the SB. However, since the maximum stent cell diameter is 3.0 mm of the SES, a “napkin-ring” is created at the branch ostium, even after dilatation with a > 3.0 mm balloon. Therefore, the next-generation DES with an open-cell design and greater reliability are thought to be ideal for this technique. Although our experience with this technique is still limited, the long-term results at 8–12 months after stenting have been excellent in all subjects. We believe that this technique will be a useful option for the treatment of bifurcation lesions that need a two-stent technique. Clinical studies with a larger number of subjects are necessary to determine if this technique truly improves the clinical outcomes for the two-stent technique.

References

1. Carrie D, Karouny E, Chouairi S, Puel J. T-shaped stent placement: A technique for the treatment of dissected bifurcation lesions. Cathet Cardiovasc Diagn 1996;37:311–313. 2. Sharma SK, Choudhury A, Lee J, et al. Simultaneous kissing stents (SKS) technique for treating bifurcation lesions in medium-to-large size coronary arteries. Am J Cardiol 2004;94:913–917. 3. Chevalier B, Glatt B, Royer T, Guyon P. Placement of coronary stents in bifurcation lesions by the “culotte” technique. Am J Cardiol 1998;82:943–949. 4. Colombo A, Stankovic G, Orlic D, et al. Modified T-stenting technique with crushing for bifurcation lesions: Immediate results and 30-day outcome. Catheter Cardiovasc Interv 2003;60:145–151. 5. Steigen TK, Maeng M, Wiseth R, et al. Randomized study on simple versus complex stenting of coronary artery bifurcation lesions: The Nordic bifurcation study. Circulation 2006;114:1955–1961. 6. Ferenc M, Gick M, Kienzle RP, et al. Randomized trial on routine vs. provisional T-stenting in the treatment of de novo coronary bifurcation lesions. Eur Heart J 2008;29:2859–2867. 7. Latib A, Colombo A. Bifurcation disease: What do we know, what should we do? JACC Cardiovasc Interv 2008;1:218–226. 8. Uretsky BF. Optimizing bifurcation stenting: The SPRINT technique. Catheter Cardiovasc Interv 2009;73:344–345. 9. Medina A, Suárez de Lezo J, Pan M. [A new classification of coronary bifurcation lesions]. Rev Esp Cardiol 2006;59:183. 10. Iakovou I, Ge L, Colombo A. Contemporary stent treatment of coronary bifurcations. J Am Coll Cardiol 2005;46:1446–1455. 11. Louvard Y, Thomas M, Dzavik V, et al. Classification of coronary artery bifurcation lesions and treatments: Time for a consensus! Catheter Cardiovasc Interv 2008;71:175–183. 12. Ormiston JA, Currie E, Webster MW, et al. Drug-eluting stents for coronary bifurcations: Insights into the crush technique. Catheter Cardiovasc Interv 2004; 63:332–336. 13. Murasato Y, Hikichi Y, Horiuch M. Stent deformation and vessel dilation after simultaneous kissing stenting in the 3-dimensional coronary bifurcation model. J Am Coll Cardiol 2009;53:A79. 14. Kaplan S, Barlis P, Dimopoulos K, et al. Culotte versus T-stenting in bifurcation lesions: Immediate clinical and angiographic results and midterm clinical follow-up. Am Heart J 2007;154:336–343. 15. Murasato Y, Hikichi Y, Horiuchi M. Examination of stent deformation and gap formation after complex stenting of left main coronary artery bifurcations using microfocus computed tomography. J Interv Cardiol 2009;22:135–144.

_____________________________________________________________________ From the Department of Cardiology, Cardiovascular Center, Shin-Koga Hospital, Kurume City, Japan. The authors report no conflicts of interest regarding the content herein. Manuscript submitted October 22, 2009, provisional acceptance given November 3, 2009, final version accepted November 30, 2009. Address for correspondence: Tomohiro Kawasaki, MD, FACC, Department of Cardiology, Cardiovascular Center, Shin-Koga Hospital 120, Tenjin-cho, Kurume, Japan, 830-8577. E-mail: to-kawasaki@mug.biglobe.ne.jp