What is the Price for Perfection for Precise Aorto-Ostial Stent Placement?

Percutaneous coronary intervention (PCI) of an aorto-ostial lesion requires precise implantation of a coronary artery stent in order to prevent adverse clinical outcomes. “Geographic miss” occurs when the lesion is not fully covered or additional stents are required, which undoubtedly will contribute to edge restenosis and stent thrombosis. Conversely, over-covering the lesion proximally complicates matters by making it difficult to cannulate the vessel coaxially for future coronary intervention.

In this issue of the Journal, Dishmon and colleagues¹ retrospectively investigated coronary angiograms and clinical outcomes in 100 consecutive patients between 2005 and 2007 who underwent PCI of native coronary artery or graft ostial lesions. This study found that the true ostium was missed in 54% of cases; proximal miss was found in 52% of them, resulting in the inability to engage the guiding catheter in 93% of cases. On the other hand, distal miss was found in 48% of cases, and additional stents were required in 38% of cases. The rates of restenosis and target lesion revascularization (TLR) were increased 3-fold when compared to patients without ostium miss. Given the findings of this study, the authors concluded that angiographically guided stent placement of ostial lesions led to a higher incidence of stent misposition and was associated with higher restenosis and TLR rates.

The emergence of stent technology led to the common practice of stent placement to reduce restenosis and, more importantly, to decrease clinical events. However, ostial stenosis is notorious for its difficulty with precise stent implantation. The accurate placement of a stent in an ostial lesion is critical, and therefore led to the development of an interesting device called the Ostial Pro Stent Positioning System. It is a nitinol device with expanded gold-plated feet that is advanced to the distal tip of the guiding catheter, which prevents deep seating of the guide catheter and facilitates accurate aorto-ostial stent placement. Fischell and colleagues² have reported a high rate of success with excellent angiographic position, as documented in their case series of 30 patients. In our experience, the device is versatile, cost-effective, and user-friendly; however, angiographic guidance is still necessary as the stent can be displaced proximally or distally. As indicated in this study, the long-term outcome of Ostial Pro guided PCI is still unknown.

Another technique used in the treatment of aorto-ostial lesions is the Szabo (anchor-wire) technique,^4,5 which consists of sidebranch wiring through the most proximal stent strut as well as main branch wiring through the stent lumen. The sidebranch wire or anchor wire prevents stent advancement beyond the ostial segment and makes possible the accurate stent implantation in the ostium. In a report by Gutierrez-Chico et al,³ the accuracy of stent placement at the ostium by the Szabo technique was reported in 78 out of 257 cases of Medina (010, 001) or aorto-ostial lesions. There were 21 cases of aorto-ostial lesions using the Szabo technique. The angiographic success rate in the whole cohort was 100% with acute procedural success of 86% and 30-day procedural success of 78%. There was no difference when compared to angiographic guidance. Theoretically, this is a technically demanding method with potential major complications, such as stent dislodgement, guidewire fracture, or stent misposition. We have reported our own experience using a 6 Fr sheath or 7 Fr sheathless transradial intervention for ostial lesions,⁶ and showed that PCI using the Szabo technique via transradial approach is safe and feasible with excellent immediate angiographic and intravascular ultrasound success rate. The 6-month major adverse cardiac event rate was 0% in this small cohort of patients. We strongly believe that there is definitely a steep learning curve for this technique before it can be applied efficiently in the treatment of all aorto-ostial lesions. Once this technique is adopted, most aorto-ostial lesions can potentially be managed as the stents are accurately placed.

In conclusion, we agree that angiographically assisted placement of aorto-ostial stent is difficult and challenging. This type of PCI is associated with high contrast load, fluoro/cine time, and overall procedural time. The Ostial Pro is a novel device addressing this issue, but it still relies on angiographic visual aid for accurate stent positioning. Meanwhile, the Szabo technique is generally anticipated to provide precise stent placement in the ostium, but has potentially catastrophic failure complications. With careful and meticulous skillfulness, we advocate that interventional cardiologists strive to acquire these techniques for accurate aorto-ostial stent implantation in the coronary arteries.

References

1. Dishmon DA, Elhaddi A, Packard K, et al. High incidence of inaccurate stent placement in the treatment of coronary aorta-ostial disease. J Invasive Cardiol 2011;23:322–326.
2. 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.
3. Gutiérrez-Chico JL, Villanueva-Benito I, Villanueva-Montoto L, et al. Szabo technique versus conventional angiographic placement in bifurcations 010-001 of Medina and in aorto-ostial stenting: Angiographic and procedural results. EuroIntervention 2010 Feb;5:801–808.
4. Kern MJ, Ouellette D, Frianeza T. A new technique to anchor stents for exact placement in ostial stenoses: The stent tail wire or Szabo technique. Catheter Cardiovasc Interv 2006;68:901–906.
5. Applegate RJ, Davis JM, Leonard JC. Treatment of ostial lesions using the Szabo technique: A case series. Catheter Cardiovasc Interv 2008;15;72:823–828.
6. Cherukuri S, Kwan J, Huang Y, et al. Feasibility of percutaneous coronary interventions using Anchor-wire (Szabo) technique via transradial approach. Catheter Cardiovasc Interv 2011;77(S1):B006

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From the Asian Service Center and Asian Heart Center, Cardiac Catheterization Laboratory and the Division of Cardiology, Beth Israel Medical Center, New York.
The authors report no conflicts of interest regarding the content herein.
Address for correspondence: Tak W. Kwan, MD, Beth Israel Medical Center, First Avenue at 16th St., New York, NY 10003. Email: kwancardio@aol.com