Cutting Balloon Angioplasty Through Stent Struts of a “Jailed” Sidebranch Ostial Lesion

Sidebranches can be compromised during high-pressure intracoronary stenting, especially in the setting of intrinsic ostial narrowing.1–3 Immediate compromise of sidebranches involves plaque shifting, spasm and thrombosis. When patients return with restenosis after coronary stenting, progressive sidebranch ostial stenosis is usually due to intimal hyperplasia from the neoproliferative response to the implanted stent. Progressive sidebranch ostial stenosis can be treated with conventional angioplasty through the struts of the stent. Although the stent struts can be effectively dilated with balloon angioplasty, elastic recoil of the stenosis often limits angiographic success. Stenting can eliminate recoil, but its use is limited by sidebranch size and angle of branch take-off. Rotational atherectomy has been attempted,4 but there are concerns about its safety.5 Cutting Balloon angioplasty is a new technique developed by Barath.6 The Cutting Balloon utilizes atherotomes bonded longitudinally to the balloon surface to make incisions directed radially into the media. Incision and dilatation of the plaque are thought to minimize trauma to the arterial wall, and to subsequently impact the neoproliferative response. Restenosis rates appear to be significantly lower when compared with balloon angioplasty.7–9 The Cutting Balloon appears to be especially effective in the treatment of in-stent restenosis.10–13 The ability of the Cutting Balloon to make micro incisions into the fibrous neoproliferative tissue facilitates the extrusion of this tissue through the stent struts,14 and appears to be a distinct advantage over balloon angioplasty. The Cutting Balloon also appears to be especially effective in the treatment of resistant coronary lesions;15,16 this advantage may facilitate the treatment of sidebranch ostial disease after stent placement. We report a case of successful Cutting Balloon angioplasty through stent struts of a severe, elastic, “jailed” sidebranch ostial lesion. Case Report. A 58-year-old man with a history of hypertension and hypercholesterolemia presented with an anterior wall myocardial infarction in June 1999; he underwent coronary angiography, which revealed a completely occluded proximal left anterior descending artery (LAD). The occlusion was successfully opened with balloon angioplasty revealing further disease in the mid-vessel LAD, as well as a severe 90% ostial diagonal branch stenosis. The middle of the LAD was stented with a 3.0 x 18 mm GFX2 stent (Applied Vascular Engineering, Santa Rosa, California). The proximal diagonal branch was then dilated with a 3.0 x 20 mm RANGER balloon (Boston Scientific/Scimed, Inc., Maple Grove, Minnesota), resulting in significant improvement of the stenosis. A 3.5 x 28 mm Duet stent (Advanced Cardiovascular Systems, Inc., Santa Clara, California) was then placed in the proximal LAD overlapping the first stent and “jailing” the diagonal branch. There was plaque shifting into the proximal diagonal branch, resulting in a residual 60% ostial diagonal stenosis. In January 2001, the patient was admitted with unstable angina and underwent follow-up coronary angiography. Moderately severe 70–80% focal in-stent stenosis within the more distal GFX2 stent and a preocclusive 95% ostial diagonal lesion (Figure 1A) were present. The ostial diagonal lesion was successfully crossed with a TRAVERSE wire (Advanced Cardiovascular Systems, Inc.) and balloon angioplasty was performed on the ostial lesion through the struts of the Duet stent with a 2.0 x 20 mm RAPTOR balloon (Cordis Corporation, Miami Lakes, Florida). The balloon was completely inflated at 8 atmospheres (atm), but a 90% stenosis remained after the balloon was deflated. Repeat angioplasty was performed using a 2.5 x 20 mm D1 balloon (Applied Vascular Engineering) at 4 atm, again resulting in full balloon inflation, but the stenosis remained unchanged (Figure 1B). The balloon angioplasty catheter was exchanged for a 2.5 x 10 mm Cutting Balloon (InterVentional Technologies Inc., San Diego, California). Using a 7 French XBLAD 4.0 guider (Cordis Corporation), the Cutting Balloon was partially advanced across the stent struts without difficulty, covering the orifice of the diagonal branch. A 60 second inflation at 10 atm was followed by a 120 second inflation at 12 atm. There was an excellent angiographic result with no residual stenosis (Figure 1C). Cutting Balloon angioplasty was also performed within the GFX2 stent using a 2.5 x 15 mm balloon with good angiographic results. Atypical chest pain prompted follow-up coronary angiography 3 days after the procedure. Both Cutting Balloon angioplasty sites were without recurrent stenosis (Figure 1D). The patient was discharged with complete resolution of his chest discomfort and his post-hospitalization course was uneventful. Discussion. In this case, Cutting Balloon angioplasty was shown to effectively treat a severe, elastic sidebranch ostial lesion through stent struts. The advantage of the Cutting Balloon over conventional angioplasty in treating resistant ostial lesions is not surprising. Because ostial lesions involve the muscular media of the parent artery, recoil of the lesion is frequently seen despite balloon dilatation. In addition, sidebranch ostial lesions after stent implantation are complicated by intimal hyperplasia from the neoproliferative response to the implanted stent. With the ability to make incisions down to the media layer, it appears that the Cutting Balloon can effectively treat restenotic ostial lesions. Treating a sidebranch ostial lesion with Cutting Balloon angioplasty through stent struts is not without challenge. One potential limitation of the Cutting Balloon is its less flexible profile. Either tortuosity of the parent artery or the angle formed by the sidebranch may prove prohibitive for this strategy in some patients. In this case, the angle between the LAD and the diagonal branch was not severe and there was no difficulty in positioning the Cutting Balloon. Another concern is difficulty traversing stent struts due to the increased crossing profile of the Cutting Balloon, which ranges from 0.041–0.046´´ depending on balloon size and atherotome number. This profile is significantly greater than those of conventional angioplasty balloons, which range from 0.024–0.028´´. The strut cell diameter differs from stent to stent. After stent expansion to 3.0 mm, the strut cell diameters range from 0.032–0.043´´ with a closed cell design, and 0.033–0.232´´ with an open cell design. In this case, the Duet stent had a closed cell design, and positioning of the Cutting Balloon was facilitated by predilatation of the stent struts. Predilatation before Cutting Balloon positioning is necessary with closed cell stents, and may be needed with most open cell stents as well. Care should be used when positioning the Cutting Balloon. Because of the substantial increase in crossing profile after initial inflation, there is a danger of balloon entrapment if the Cutting Balloon is positioned completely in the sidebranch.17 Thus, it is recommended that part of the Cutting Balloon remains well within the lumen of the parent vessel (Figure 2). In summary, this case demonstrates the efficacy of Cutting Balloon angioplasty through a stent strut to treat a severe, elastic sidebranch ostial lesion. This may be an optimal strategy for the treatment of elastic lesions in smaller vessels that are suboptimal for stenting. The long-term benefits of a Cutting Balloon for the treatment of sidebranch ostial lesions are still to be determined.

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