Case Report

Case of Dislodged Stent Lost in Septal Channel during Stent Delivery in Complex Chronic Total Occlusion of Right Coronary Artery

Makoto Utsunomiya, MD, Tomoko Kobayashi, MD, Shigeru Nakamura, MD
Makoto Utsunomiya, MD, Tomoko Kobayashi, MD, Shigeru Nakamura, MD
From the Cardiovascular center, Kyoto-Katsura Hospital, Kyoto, Japan. The authors report no conflicts of interest regarding the content herein. Manuscript submitted May 4, 2009, provisional acceptance given May 28, 2009, and final version accepted June 12, 2009. Address for correspondence: Makoto Utsunomiya, MD, Cardiovascular center, Kyoto-Katsura Hospital, 17 Yamada-Hirao-cho, Nishikyo-ku, Kyoto, Japan 615-8256. E-mail: kcvc.utsunomiya@katsura.com

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ABSTRACT: The retrograde approach is a recently introduced technique for percutaneous coronary intervention (PCI) of chronic total occlusions (CTO). To improve the long-term patency rate, stent implantation is necessary for CTO; however, antegrade stent delivery to the lesion is sometimes impossible in cases where there is a complex coronary anatomy. Although there have been some reports that retrograde stent delivery is useful in such cases, it is technically very challenging. We report a case of attempted stent deployment via the septal channel to treat a CTO, whereby the proximal right coronary artery was 360º-looped and the stent dislodged in the septal channel.

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J INVASIVE CARDIOL 2009;21:E229–E233
Previous reports demonstrate that successful recanalization of chronic total occlusions (CTO) offers some clinical benefits such as improvement of angina, left ventricular function and mortality rates.1–4 Despite advances in technology, percutaneous revascularization of CTO lesions is technically challenging. With the antegrade approach, the procedural success rate is approximately 60–80%.5,6 To improve the success rate of CTO procedures, the retrograde approach and the combination of controlled antegrade and retrograde subintimal tracking (CART) techniques have been invented.7,8 The retrograde approach to reach CTO lesions (including the CART technique) has increased the initial success rate of wire crossing. Even if wiring is successful using the retrograde approach, the lesion is fixed by the stent antegradely. However, antegrade stent delivery cannot be applied in some particular cases due to malformation and deviation of the coronary arteries and high flexion. There are some reports on retrograde stent delivery.9,10 Even though retrograde stent delivery is an effective method, it can hardly be considered safe and secure. In our patient, despite the fact that a retrograde-approach PCI was performed to treat a CTO lesion in the right coronary artery (RCA) with high flexion, and that we were able to perform retrograde wiring, the stent was lost in the septal channel during retrograde stent delivery. Case Presentation. A 76 year-old male developed acute myocardial infarction of the inferior wall in December 2006, and underwent catheterization at another hospital. His mid-RCA was looped and his distal RCA was occluded. Successful recanalization was achieved with a balloon, and a 3.5 x 15 mm Multilink Vision stent (Abbott Vascular, Abbott Park, Illinois) was delivered to the lesion with deep engagement. After stent implantation, spiral dissection occurred at the proximal RCA by the guiding catheter. A 3.5 x 23 mm MultiLink Vision stent was deployed at the entrance of the dissection, which was the proximal half-pipe of 360º-looped portion. A final angiogram showed no-flow because the hematoma extended to the distal site and the true lumen was collapsed (Figure 1). In January 2008, the patient experienced angina and was referred to our hospital to treat the occluded RCA. Exercise electrocardiographic results before treatment showed a typical ischemic pattern. Diagnostic angiography showed that the RCA was occluded in the proximal stent, and bridge collaterals to the mid RCA were observed (Figure 2). The stent at the distal end was also occluded. The left coronary artery (LCA) had no significant stenosis. The distal RCA was filled by septal channels from the left anterior descending (LAD) and left circumflex (LCX) arteries (Figure 3). Due to the patient’s complex CTO lesion, a bidirectional approach was employed. The wire was manipulated by a retrograde approach, and the Fielder X-Tream wire (Asahi Intec, Tokyo, Japan) and Transit catheter (Cordis Corp., Miami Lakes, Florida) were able to advance to the distal RCA via the septal perforator. The septal channel was dilated with a 1.25 mm Ryujin OTW balloon (Terumo Corp., Japan). The distal occluded stent was crossed with a Miracle 6 g wire (Asahi Intec, Japan) in a retrograde fashion, but did not cross the proximal occluded segment. A JR4.0 guiding catheter was engaged in the RCA and a Rinato (Asahi Intec) guidewire was advanced through the stent-occluded lesion antegradely, dilating it to create a target space for the retrograde guidewire. The retrograde guidewire was passed through the occlusion and entered the aorta (Figure 4). The wire tip was snared from the JR guide and a balloon entered the RCA guiding catheter. The retrograde wire was exchanged for a 300 cm Flexi-Wire (Abbott Vascular) and pulled out of the RCA guide catheter. Predilatation was performed using a 3.0 x 20 mm Ryujin Plus balloon antegradely, and antegrade stent delivery was attempted. However, a Taxus® Express stent (Boston Scientific Corp., Natick, Massachusetts) was unable to cross the stented segment. To straighten the previously stented segment, a buddy-wire technique using a 0.025 inch wire was attempted, but the stent could not cross the lesion. A possible cause for this was that the previously implanted stent in the looped coronary artery was deformed by the support wire (Figure 5). It was not clear how to proceed, so the procedure was stopped . A dose of 196 ml of contrast medium was used during this procedure, the total procedure time was > 6 hours, and the fluoroscopy time was 178 minutes. Severe residual stenosis was observed, however, antegrade flow was established with thrombolysis in myocardial infarction (TIMI)-2 flow (Figure 6). A second attempt was scheduled for 1 week later. In the 360º-looped artery, the proximal half-pipe was already stented. A residual dissection was located in the distal half-pipe. Stent deployment via a retrograde approach was planned without crossing the proximal half-pipe (Figure 7). Blood flow had improved compared to the final angiogram after the first intervention. A SUOH wire (Asahi Intec) with a Finecross catheter (Terumo, Japan) easily crossed the lesion via the septal channel. The SUOH was captured with a snare and a 2.5 mm x 15 mm Apex balloon (Boston Scientific) crossed the looped lesion via a retrograde approach (Figure 8). Following predilatation with a 2.5 mm balloon, a 2.75 x 18 mm Micro Driver (Medtronic, Inc., Minneapolis, Minnesota) was advanced retrogradely. However, the Micro Driver was unable to pass the collateral connection from the septal channel. Therefore, a 1.5 x 15mm Apex Flex balloon dilated the septal channel at 10 atm. In the same septal channel, 1.25 mm balloon had been dilated in the first intervention. The 2.75 x 18 mm Micro Driver was advanced once again. This time, the stent crossed the septal channel, however, it stacked at a curved portion in the distal RCA. When the system was pulled, the stent dislodged in the septal channel (Figure 10). There was no injury or hemorrhage in the septal channel, and flow was not disturbed, hence, stent delivery via the retrograde approach was abandoned at this point. Another antegrade stent implantation was attempted. Secondly, despite using the 5-in-7 catheter technique performed by inserting the 5 Fr Heartrail guide catheter (Terumo Corp.) into the Brite Tip 7 Fr guide catheter (Cordis), we could not advance the 5 Fr catheter distal to the lesion, even with combined use of the anchor-balloon technique. We abandoned stent implantation retrogradely and antegradely and ended the procedure with balloon dilatation alone. A 301 ml dose of contrast was used during this procedure, with a total procedure time of > 2 hours and a fluoroscopy time of 55 minutes. The final angiogram showed antegrade TIMI 3 flow with a dissection at the looped lesion (Figure 11). The patient’s symptoms temporarily improved, however, angina recurred after a while. Angiography at 3-month follow up showed a 90% focal stenosis. The lesion was treated with conventional balloon angioplasty using an antegrade approach. Six-month follow up showed Discussion. The percentage of CTO lesions in coronary artery disease is approximately 35%.11 However, the success rate of PCI for CTO is not high enough. The main factor in failed procedures is unsuccessful wire-crossing of the lesion. The retrograde approach has greatly enhanced wire-crossing success rates. The efficacy of the retrograde approach has been established in recent years. However, even if the operator is successful in passing the wire to the lesion using a retrograde approach, treatment of the CTO lesion is not complete. It is sometimes difficult to deliver the stent to the lesion antegradely, as in cases of deviation of a coronary artery and proximal extreme fixation. And some cases of antegrade stent delivery are impossible. There have been reports on retrograde stent delivery as an option for the treatment in such cases. However, such a method cannot be said to be safe and is considered to pose a high risk of complications. We have previously reported a case of delivery of a 2.5 x 18 mm Cypher sirolimus-eluting stent (Cordis) retrogradely for a CTO lesion in a highly deviated RCA. In that case, since a guiding catheter could not be engaged in the RCA, the stent was advanced to the RCA through a septal perforator following adequate septal dilatation for the septal perforator. The factors behind the success were likely due to the collateral channel, which was relatively straight, and adequate dilatation was possible without complications. Furthermore, the patient had an obtuse marginal 1 branch of the septal area without strong contraction in the septal channel during the cardiac cycle. The case presented here involved a CTO lesion that developed due to the stent implanted in an extreme flexure of the proximal RCA. We succeeded in wiring using a retrograde approach and were able to pass the balloon antegradely, though when a stent was used for delivery, the previously deployed stent was deformed, and the stent could not be antegradely passed. Therefore, we decided to deliver the stent retrogradely. Stent delivery failure via a septal channel is thought to be due to a flexed septal channel. Because the small channel, there was a risk that the stent system would be choked during delivery. We chose a ring stent that did not have a sticky surface on the delivery system and had mildly-sharpened edges, which yield high trackability and conformability. Also, it has less risk of channel perforation, even if the stent is lost in the channel. The diameter of the stent delivery system was 1.02 mm.We considered it possible to pass through the channel because it was dilated with a 1.5 mm balloon, which may be small, but it was used to avoid the risk of channel perforation with the 2.0 mm balloon. Though stent was even left in the septal channel, there were no obvious injuries or complications, including perforation or hemorrhage. No CK elevation was observed. Septal-channel flow was maintained, and even though the RCA was occluded, the region was not ischemic. Three-month follow-up angiography showed a 90% focal stenosis, which was treated with plain-old balloon angioplasty via an antegrade approach. Six-month follow up showed References 1. Suero JA, Marso SP, Jones PG, et al. 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