“Sepal Wire Technique” — A Novel Technique for Aorto-ostial Left Main Stenting

ABSTRACT: Aorto-ostial left main (LM) percutaneous coronary intervention (PCI) remains a challenge in interventional cardiology, as precise positioning of stents using conventional angiographic landmarks is difficult. Previously described techniques either involve the use of additional complex steps or commercially available special devices that carry extra costs. We describe a novel technique for ostial LM stent positioning that makes use of a simple additional workhorse wire curling back into the aorta like the sepal of a flower.

J INVASIVE CARDIOL 2011;23:211–212

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Aorto-ostial left main (LM) percutaneous coronary intervention (PCI) remains a challenge in interventional cardiology, as precise positioning of stents using conventional angiographic landmarks is difficult.^1–4 A stent placed just distal to the true ostium leads to geographical miss and a high incidence of restenosis.^1,2 If a second stent is deployed to cover the geographical miss, this will not only add to the cost of the procedure, but also potentially increases the risk of stent thrombosis due to unnecessary stent overlapping. Implantation of another stent is also technically difficult when the LM is rather short. It is equally undesirable if a stent is placed too proximally with too much stent length protruding into the aorta.^5,6 Proper engagement of the guiding catheter becomes difficult if not impossible should re-intervention be required in the future. These issues have become ever more important when the number of LM PCI procedures increases, as recent international guidelines have advanced the indication of LM PCI. A novel method is described in this case report using a simple technique for treatment of aorto-ostial disease.

Case description. A 73-year-old man with stable angina and a significant positive myocardial perfusion scan underwent elective coronary angiogram at our institution. There was significant ostial LM disease by angiography (Figure 1) and intravascular ultrasound imaging (IVUS). The best angiographic views were the right and left anterior oblique (RAO and LAO) with a cranial projection. A 6 Fr Judkins 4 guiding catheter was used and a workhorse wire inserted into the left anterior descending artery. Predilatation was done with a 3.0 mm balloon. Before delivery of a 4.0 mm LM stent, another workhorse coronary wire was introduced into the guide and curled back into the aorta so that it now looked like the sepal of a flower and the guiding catheter like the flower stalk. The LM stent was then able to be advanced through the guiding catheter into the LM. At this stage, the guiding catheter was manipulated to situate closely to the ostium, but would be prevented from fully intubating into the LM by the “sepal” wire, and a more co-axial position was thus achieved. This also allowed good contrast filling for visualization of the anatomical relationship (Figure 2). The 4.0 mm stent was deployed at 16 atmospheres (Figure 3). Final angiography showed excellent results (Figure 4), with the guiding catheter engaging easily into the LM after removal of the “sepal” wire. IVUS confirmed excellent ostial stent coverage (Figure 5).

Discussion. Ideally, a stent should be placed right at the LM ostium or protruding 1–2 mm into the aortic side in order to achieve sufficient lesion coverage and adequate expansion to prevent recoil of the more fibro-elastic aorto-ostial junction. However, this can be technically difficult for two major reasons, the first of which involves an anatomical factor. The take-off of the LM from the aorta is almost never 90 degrees. Stent placement should ensure that the stent adequately covers the superior aspect of the LM. This also means that some stent length will have to protrude into the aorta at the inferior aspect of the LM. The more acute the take-off angle, the more stent length will be needed to protrude back into the aorta if adequate coverage of the true ostium is required. The fact that this take-off angle is not 90 degrees also makes it difficult to find good angiographic views that clearly delineate this relationship. Secondly, conventional fluoroscopic guidance for LM stent positioning is always difficult, as there is bound to be bobbing and to-and-fro movement of the stent delivery system during each cardiac contraction and breathing movement in a guiding catheter that is deliberately partially disengaged. Using conventional fluoroscopic guidance alone, the true LM ostium is missed in 60% of the cases.⁷ Szabo³ and Wong⁸ reported special techniques to help accurate positioning of the LM stent by threading another wire through one of the proximal stent cells. In order to achieve this, the stent delivery balloon has to be partially inflated to allow threading of the second wire and then properly re-crimped to ensure smooth delivery of the stent. Wong⁸ showed favorable angiographic and IVUS outcomes using his technique for treatment of ostial disease. Use of a commercially designed ostial stent positioning system (Ostial Pro™, Ostial Solutions, Inc., Kalamazoo, Michigan) has also been favorably reported.⁷ Yet, these methods either involve additional complicated steps or increased cost for the procedure.

Our novel technique is simple and easy to implement. The only additional device is a regular workhorse wire. This wire enables the guiding catheter to park closely to the true ostium, yet it cannot be intubated fully into the LM. It allows good contrast filling for visualization of the anatomical relationship and the wire itself also helps to demarcate the silhouette of the aortic sinus. Finally, precise adjustment of the stent’s position is made easy because the wire stops the guiding catheter from being “sucked” into the LM when one attempts to fine-tune the stent position by pulling the stent out to cover the true ostium. This technique is simple and safe and is very helpful for accurate ostial stent positioning. Finally, it is still of paramount importance to find good angiographic views to clearly show the anatomical relationship, which can be highly variable among individual patients. In our experience, right anterior oblique and left anterior oblique cranial projections are usually the best angles, as in this case. A final IVUS study helps confirm adequate stent expansion and apposition in addition to confirming the exact stent location.

References

1. Teirstein P, Stratienko AA, Schatz RA. Coronary stenting for ostial stenosis: Initial results and six-month follow-up. Circulation 1991;84(Suppl 2):II–250.
2. Zampieri P, Colombo A, Almogar Y et al. Result of coronary stenting of ostial lesions. Am J Cardiol 1994;73:901–903.
3. Szabo S, Abramowitz B, Vaitkus PT. New technique for aorto-ostial stent placement. Am J Cardiol 2005;96:96H–212H.
4. Kern MJ, Ouellette D, Frianeza T. A new technique to anchor stents for exact placement in ostial stenosis: The stent tail wire or Szabo technique. Catheter Cardiovasc Interv 2006;68:901–906.
5. Kaplan S, Barlis P, Tanigawa J, et al. Unconventional treatment of aorto-ostial instent restenosis with marked protrusion into the aorta. J Cardiovasc Med 2008:2:184–186.
6. Chetcuti SJ, Moscucci M. Double-wire technique for access into a protruding aorto-ostial stent for treatment of instent-restenosis. Catheter Cardiovasc Interv 2004;62:214–217.
7. Fischell TA, Saltiel FS, Foster MT, et al. Initial clinical experience using an ostial stent positioning system (Ostial Pro™) for the accurate placement of stents in the treatment of coronary aorto-ostial lesions. J Invasive Cardiol 2009;21:53–59.
8. Wong P. Two years experience of a simple technique of precise ostial coronary stenting. Catheter Cardiovasc Interv 2008;72:331–334.