Provisional stenting of the side branch seems to be an attractive strategy even in the drug-eluting stent era. One of the technical problems in provisional side-branch stenting is how to deliver the stent through a stent strut. In this case presentation, we suggest a novel method for deploying a stent through the use of a 5 Fr guiding catheter. A 5 Fr guiding catheter within a 7 Fr guiding catheter was advanced to the lesion, through a stent strut, facilitating the deployment of the stent. This system permits negotiation of the stent strut that otherwise obstructs stent passage.

       Stenting has reduced restenosis and the need for repeat intervention following percutaneous coronary intervention (PCI).¹ However, lesions at the coronary bifurcation still present a challenge to the interventional cardiologist.² To overcome the problem of restenosis and to facilitate stent deployment, various stenting techniques have evolved for the treatment of bifurcation lesions.^3–9 Moreover, the development of a low-profile balloon and second generation stents has made it possible to carry out complex stenting techniques. Although these developments reduce the complication rate, there is still the problem of occasional procedural failure, as we have experienced. In this case report, we demonstrate a novel PCI technique for deploying the stent to the highly angulated side branch through a stent strut.

       Case Report. A 79-year-old female underwent coronary angiography 3 years earlier to evaluate her chest discomfort upon effort. The angiogram demonstrated 75% left main trunk (LMT) stenosis with two-vessel disease. She refused coronary aorta bypass graft surgery, and had been managed successfully via medical means until her angina pectoris worsened and she suffered from prolonged severe chest pain at rest. On her transfer to our hospital, a coronary angiogram showed severe LMT stenosis and diffuse stenosis of the left anterior descending artery (LAD). The left circumflex coronary artery (LCX) also showed severe stenosis at the proximal site and was totally occluded at the distal site (Figure 1A). We planned to deploy a stent into the LMT and treat the LCX provisionally. Prior to intervention, an intra-aortic balloon pump (IABP) was initiated. We then inserted a 7 Fr FL-4 guiding catheter into the left coronary artery via the right femoral artery. Initially, plaque modification by rotational atherectomy with 1.25 mm and 1.75 mm burrs (Boston Scientific, Natick, Massachusetts) was performed through the LMT to the LAD in order to prevent the deterioration of side branch coronary flow. A 3.0 mm x 23 mm Cypher™ stent (Cordis Corp., Miami, Florida) was then deployed into the LMT and dilated to 16 atmospheres (Figure 1B). After the LMT stent placement, the patient complained of chest pain. We decided to also treat the lesion in the LCX via dilatation through a stent strut. As shown in Figure 1C, the angle of bifurcation was classified as being T-shaped and the degree of

Figure 1

(A) Baseline angiogram showed severe LMT stenosis and a diffuse LAD and LCX lesion. (B) Angiogram after DES deployment into the LMT. (C) The angle of bifurcation was unchanged during high-pressure balloon dilatation. (D) Final angiogram after provisional side branch stenting.

angulation was unchanged during high-pressure balloon dilatation. Next, we tried to deploy a 2.5 mm x 23 mm Cypher™ stent to the LCX. Deployment of a stent is a difficult procedure because the stent has to be deployed into the highly angulated LCX through the stent strut. Neither the buddy wire technique nor the anchor technique were useful in deploying the stent. We decided to use a 5 Fr guiding catheter to deliver the stent. The procedure was undertaken by the following the steps: (1) The PCI guidewire and the 7 Fr guiding catheter (100 cm in length) remained in situ. (2) A 5 Fr catheter (Heartrail, Terumo, Japan) was

Figure 2

(A) A 5 Fr guiding catheter was introduced into the LCX with the retained balloon. a-1 denotes the tip of the balloon catheter, a-2 the tip of 5 Fr guiding catheter. (B) The stent was deployed through the 5 Fr guiding catheter. b-1 denotes the tip of 5 Fr catheter, b-2 the tip of the stent. (C) A 5 Fr guiding catheter was pulled back into the 7 Fr guiding catheter. c-1 denotes the tip of 5 Fr catheter, c-2 the tip of the stent.

inserted along the PCI guidewire into a 7 Fr guiding catheter. This guiding catheter has a very soft 13 cm shaft at the end and an overall length of 120 cm, whereas the 7 Fr guiding catheter is 100 cm long. (3) A balloon catheter was advanced to the LCX. (4) A 5 Fr guiding catheter was introduced into the LCX with the retained balloon. (5) The balloon catheter was removed from the 5 Fr guiding catheter. (6) The stent was then deployed through the 5 Fr guiding catheter that remained in the LCX. (7) The 5 Fr guiding catheter was pulled back into the 7 Fr guiding catheter.⁸ The stent was dilated (Figures 2 and 3), and finally, a kissing balloon procedure was performed. The IABP was discontinued on the same day. The patient’s hospital course was uneventful and she was discharged 3 days later.

       Discussion. A recent paper showed that the kissing stent technique could not overcome the problem of restenosis despite the introduction of drug-eluting stents (DES).¹⁰ Restenosis at the side branch in particular remains a problem. The rate of side branch restenosis was 21.8% and 14.2%, respectively, for both branch stenting strategies and in the provisional stenting arm.¹⁰ These outcomes suggest that provisional side branch stenting is still an attractive strategy to treat bifurcation lesions, whereas there is no appropriate technique to use when treating bifurcations with a Cypher stent. We have no definitive explanation for these occurrences. However, as a technical consideration, the kissing

Figure 3

A schematic drawing of a stent deployment procedure. (A) A balloon catheter was advanced to the LCX. (B) A 5 Fr guiding catheter was introduced into the LCX with the retained balloon. (C) The balloon catheter was removed from the 5 Fr guiding catheter. (D) The stent was then deployed through the 5 Fr guiding catheter that remained in the LCX. (E) The 5 Fr guiding catheter was pulled back into the 7 Fr guiding catheter. (F) The stent was dilated.

balloon procedure has been demonstrated to be useful in avoiding main vessel deformation. Therefore, we performed the kissing balloon procedure after provisional stenting.
       There are ongoing efforts to develop new stents, guiding catheters and guidewires, as well as new deployment techniques, in order to improve clinical outcomes and reproducibility. As a result, side branch stenting problems are becoming less frequent.¹⁰ However, rewiring vessels, balloon crossing and stent delivery through a stent strut can be potentially difficult in cases of provisional side branch stenting. Our study demonstrated a new stent delivery method to treat bifurcation lesions.
       5 Fr catheter in the larger-sized guiding catheter. To create a strengthened backup support, various approaches can be utilized, including the use of a buddy wire,¹¹ anchor technique¹² and deep seating of the guiding catheter.¹³ These techniques can provide a useful means for delivering the stent through a stent strut. Our approach offers another method, namely, the use of a 5 Fr guiding catheter. A 5 Fr Heartrail catheter has a very soft 13 cm tip that can easily negotiate the tortuous coronary artery and be directed deeply into the artery. To insert the 5 Fr guiding catheter, the balloon catheter was left in place in the LCX. This procedure provides easy negotiation of the stent strut deployed in the LMT. Furthermore, the flexible tip of the 5 Fr guiding catheter minimizes the risk of possible injury to the coronary artery and stent strut. On the other hand, the applicability of this system might be limited to adequate coverage of the ostium. This could be a potential limitation of this technique.
       We conclude that the use of a 5 Fr guiding catheter within a larger guiding catheter can be useful to not only achieve better backup support, but to negotiate the stent strut as well. This system makes it possible to deploy a stent in lesions where such deployment is otherwise difficult.

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