Ostial RCA Intervention: Guiding Catheter Challenges and Use of a Buddy Wire to Perform Focused-Force Angioplasty on a Severely
- Volume 18 - Issue 12 - December, 2006
- Posted on: 8/1/08
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Case Report. A 67-year-old female presented to our catheterization laboratory with a recent history of unstable angina for 3 weeks. Her cardiac markers were normal. Her past history was significant for diabetes, hyperlipidemia, hypertension and obesity. She subsequently underwent stress testing at another hospital, which was strongly positive. The paieint was therefore referred for angiography.
The left main coronary artery was unremarkable and the left anterior descending vessel had mild disease only. A small-caliber first obtuse marginal had a tight ostial lesion and the circumflex had mild-to-moderate disease. The culprit stenosis appeared to be a critical 95–99% stenosis at the ostium of the right coronary artery (RCA) with moderate disease distally at the proximal segment of the posterior descending branch, and mild stenosis in the mid RCA (Figure 1). There was only TIMI 2 flow down the RCA.
There was significant difficulty in intubating the RCA with both JR4 and Williams right (3DRC/No-Torque) diagnostic catheters. Therefore, adequate nonselective pictures were taken with the Williams right (3DRC/No-Torque) catheter, which came reasonably close to the ostium (Figure 1). An Amplatz left catheter was not tried due to the risk of injuring or dissecting such critical and calcified ostial disease. A multipurpose or Amplatz right catheter were thought to be the wrong geometry for engagement of this ostium. The cineangiographic images showed a thick bar of calcium at the aorto-ostial junction, preventing engagement of our catheters (Figure 1). After discussion with the patient and family regarding the risk of the procedure and the possibility of requiring single-vessel bypass surgery, we opted for percutaneous intervention.
Multiple attempts to engage the ostium of the RCA with a JR4, hockey stick (HS 1) and multipurpose guiding catheters were unsuccessful. The hockey stick guider was able to subselectively cannulate the conus branch which had a separate ostium, however it was not possible to wire the RCA from this position (Figure 2). Although the Williams or 3DRC/No-Torque guiding catheter would have been a good choice due to its precurved geometry requiring minimal manipulation to engage the RCA, this was unfortunately not available to us. Therefore, a left internal mammary artery (LIMA) guiding catheter was tried as a last resort, which fortunately, after much manipulation, gave reasonable opacification of the RCA and sat just outside the RCA ostium. At this point, a Pilot 50™ wire (Guidant Corp., Indianapolis, Indiana) was passed into the distal RCA by wiring the ostium “from a distance”. Once the Pilot 50 wire was very distal using the “railroad” method, the guider was then positioned closer to the true ostium. We anticipated significant difficulty in passing equipment with a critical calcified lesion and little guide support, therefore, a second Pilot 50™ “buddy wire” was passed into the distal RCA (Figure 3). The intent of the buddy wire was dual: first for guide support, and second as an instrument for “focused-force” angioplasty for this calcified lesion. “Focused-force” angioplasty essentially utilizes a device such as the Cutting Balloon Ultra® (Boston Scientific Corp., Natick, Massachusetts), FX miniRAIL® catheter (Guidant Corp.), or a buddy wire to apply the force of the expanding balloon along the planes of the blades (cutting balloon) or the wire (FX miniRAIL® or buddy wire) alongside the inflated balloon in a concentrated manner to achieve controlled plaque dissection for resistant or calcified lesions and to prevent balloon slippage.
Our concern here was two-fold: sudden high-pressure dilatation could lead to RCA dissection, or even worse, retrograde aortic dissection due to the aorto-ostial junction calcium bar disruption. We therefore started with the approach of multiple inflations with escalating balloon sizes to gently perform plaque modification with the second buddy wire acting as a focused-force instrument. A 1.5 x 20 mm Mercury balloon (Abbott Laboratories, Abbott Park, Illinois) was inflated to 10 atmospheres (atm) and then 12 atm at the lesion and into the aorto-ostial junction of the RCA. Guide manipulation was performed not by the push-pull method, but rather by using counterclockwise rotation to slide it superiorly in the aorta and clockwise to reapproximate it to the ostium. The LIMA catheter has a very different torque response than the JR4 and is much less amenable to “push and pull” for engagement. Next, a 2.0 x 20 mm Mercury balloon was inflated to 12 atm, followed by another inflation to 12 atm and finally 15 atm at the very ostium. This improved the lumen diameter slightly, although there was still severe elastic recoil from this very calcified lesion. A 2.5 x 20 mm Mercury balloon was therefore inflated to 12 atm and subsequently to 15 atm, with significant opening of the critical lesion (Figure 4). Next, a Taxus® Express 2™ 3.5 x 24 mm drug-eluting stent (Boston Scientific) was placed, with 1–2 mm hanging out into the aorta. When we tried to withdraw the buddy wire, the stability of the guide catheter was compromised, with the guider prolapsing further into the aorta, thus this buddy wire was left in place. The stent was deployed at 15 atm initially, with good positioning and complete ostial coverage. The buddy wire was then removed with relative ease. The stent balloon was then pulled back 1 mm and inflated to 20 atm to upsize the stent (Figure 5). A 3.75 x 12 mm Quantum™ noncompliant balloon (Boston Scientific) was then inflated to 18 atm at the ostium to flare the stent struts into the aorta and to ensure good apposition of the stent at the most calcified segment. An excellent result was obtained, with complete ostial coverage and no dissection was present distally (Figure 6). Heparin and eptifibatide (Integrilin®, COR Therapeutics, Inc., South San Francisco, California) were used during the procedure, and aspirin and clopidogrel (Plavix™, Sanofi-Synthelabo, Inc., New York, New York) were prescribed long term. The patient was doing well 1 month later, with no further symptoms.
Discussion. Ostial lesions present many challenges for percutaneous intervention. Coronary dissection, poor guide backup, lesion rigidity and calcification, elastic recoil and angiographic restenosis represent only some of the difficulties of percutaneous intervention of ostial lesions. With the advent of stenting, restenosis rates as low as 16% have been reported with bare-metal stent placement in ostial lesions.10 In a small, nonrandomized, prospective study, the use of sirolimus-eluting stents for all ostial coronary lesions (including left main, RCA, LAD, circumflex and vein graft) yielded a target vessel revascularization rate of 10%.11 Ablation technologies including rotational and directional atherectomy remain options for moderately or severely calcified ostial lesions. These techniques, however, require good guide backup and coaxial alignment for safe completion. The efficacy of rotational atherectomy with adjunctive stenting for ostial RCA stenosis was documented in a study by Motwani et al.10 A target lesion revascularization rate of 16% with a procedural success rate of 97.5% was demonstrated with this approach.10 Although ostial percutaneous intervention has been proven to be quite safe, with similar procedural success rates as proximal lesions, there is a higher need for repeat intervention.12
The buddy wire or the use of the second 0.014-inch wire alongside the primary wire for advancing equipment is a very useful tool to accomplish technically challenging procedures, often simply. The buddy wire can be used to reduce balloon slippage (“melon seeding”) during dilatation of in-stent restenotic lesions and to supplement inadequate guide catheter backup. It is also useful in procedures in vessels with significant tortuosity/angulation, where it aids in distal stent delivery and also helps to cross a proximal stent or calcified segment.13 However, the buddy wire has also been reported as an instrument for successful “focused-force” angioplasty in an inadequately expanded stent.14 The Cutting Balloon Ultra and the FX miniRAIL catheter apply essentially the same concept of controlled dissection of the vessel wall to perhaps improve vessel compliance.15
To date, there have been no reported cases of a buddy wire utilized to perform “focused-force” angioplasty on an ostial calcified lesion while simultaneously providing the supplemental support for weak guiding catheter backup. The Cutting Balloon is a reasonably bulky device requiring good backup and the rotational atherectomy catheter requires coaxial guider alignment, both of which could not be achieved in our case. Our case highlights the importance of understanding guiding catheter geometry and selection, which allows the operator to manipulate the device easily in and out of the ostium, allowing for optimal device placement and dilatation of the true ostium of the vessel involved. A method of multiple and escalating diameter balloon inflations, together with the focused force of a buddy wire, allowed for sufficient plaque modification to easily pass a large-diameter drug-eluting stent in a heavily calcified critical ostial RCA lesion without any distal or aortic dissection, and an angiographically optimal result and a good medium-term clinical outcome. Limitations of our approach include the alternate use of a more supportive wire as a buddy wire such as the Extra Sport™ (Guidant) or the Balanced Heavyweight Wire™ (Guidant) to provide perhaps greater stability, rather than a second moderate-weight Pilot 50 wire (as was used in our case). The use of a hydrophilic wire as a buddy wire carries a small but theoretical risk of “stripping” the hydrophilic coating of the distal tip of the Pilot 50 wire, and perhaps wire loss during withdrawal of the second wire after stent deployment. Although this event is extremely rare if the stent deployment pressures are not very high, the risk is nevertheless present. With our patient, we had an Extra Sport wire ready if the second Pilot 50 did not provide adequate guiding catheter support. Fortunately, this was not required. Our stent was deployed at a moderate pressure initially, and the Pilot 50 wire was fortunately removed with ease before the stent was expanded to high pressures of 20 atm. However, it is important to keep the above limitations in mind when utilizing this technique, and it may perhaps be more ideal to utilize a nonhydrophilic wire as the buddy wire whenever possible.