Treatment of Complex LAD-Diagonal Bifurcation Disease Using Paclitaxel Drug-eluting Stents

The optimal treatment of bifurcation disease remains a challenging clinical problem.¹ Although numerous techniques and strategies have been explored and reported,^2–7 including “crushing” a drug-eluting stent with another drug-eluting stent, significant problems, including restenosis, remain.⁸ The long-term safety of the “crush” technique, because of three layers of drug-eluting material, remains uncertain. Recently, the concept of “double-barrel” or “kissing” drug-eluting stenting has been proposed for recreating the left anterior descending (LAD)-left circumflex (LCX) bifurcation when left main disease needs to be treated percutaneously. This technique theoretically reduces the risk of excessive drug in one area of the stented vessel.⁹ We present a case of a paclitaxel drug-eluting stent that was hand-crimped onto two monorail balloons to treat an aneurysmal segment of a proximal portion of an LAD, with “kissing” stenting within this proximal stent using two additional paclitaxel drug-eluting stents to recreate an LAD-diagonal (DX) bifurcation. Case Report. A 46-year-old man was referred to undergo percutaneous revascularization of an LAD and DX vessel. The patient had a history of hypercholesterolemia and hypertension. As part of an evaluation for progressive chest pain, a non-invasive perfusion nuclear study was performed which showed anterior ischemia. Recent cardiac catheterization had demonstrated an LAD-DX bifurcation lesion, as well as a high-grade, mid-right coronary stenosis which appeared to be associated with thrombus. He had undergone successful balloon angioplasty and paclitaxel drug-eluting stenting of the right coronary artery, with staging of the LAD bifurcation stenosis. The patient’s LAD anatomy was complex, as is shown in Figure 1, with an aneurysmal segment just prior to the LAD-DX bifurcation. In addition, there was significant obstructive disease of the LAD distal to the DX, as well as diffuse disease of the large DX vessel itself. We proceeded with “kissing” balloon angioplasty of the bifurcation using 2.5 x 20 mm monorail balloons. We then deployed a 3.5 x 16 mm Taxus™ stent (Boston Scientific, Maple Grove, Minnesota) outside of the body, and hand-crimped the stent on the two previously-used monorail balloons (Figure 2). The stent was advanced on the two monorail balloons to the LAD-DX bifurcation, and was deployed there using the two monorail balloons. Next, 3.0 x 20 mm Taxus stents were placed in the LAD and DX vessels and deployed using a “kissing” technique in the distal portion of the previously-placed Taxus stent. Approximately 3 mm of overlap within the proximal stent was achieved. While the angiographic appearance looked reasonable, intracoronary ultrasound (ICUS) revealed significant stent under-expansion of both the 3.0 x 20 mm Taxus stents. The suboptimally deployed stent regions were post-dilated with “kissing” 2.75 x 18 mm PowerSail™ (Guidant Corporation, Temecula, California) monorail balloons to 20 atm, as was the proximal stent. The subsequent ICUS image (Figure 3) showed excellent stent expansion in the “double-barrel” region, and excellent stent apposition of the proximal Taxus stent. The final angiographic result is shown in Figure 4. Because the areas of the “kissing” stents unapposed to the vessel wall may be associated with an elevated risk of subacute stent thrombosis,9 we asked the patient to continue aspirin and clopidogrel therapy for at least one year. At six-month follow-up, the patient was asymptomatic and had no evidence of major adverse coronary events (MACE). Discussion. Treatment of bifurcation disease when both vessels of the bifurcation are of sufficient caliber to merit revascularization is problematic. Optimal branch vessel disease therapy is hindered by the absence of side branch access stents, although commercial availability is expected soon. Bifurcation disease is frequently treated with drug-eluting stent placement in the main channel,¹⁰ with provisional angioplasty and/or additional stenting in the branch vessel.^4,8 However, these techniques are associated with higher rates of restenosis, even with drug-eluting stents, than is observed after stenting of the major epicardial vessels alone. Moreover, technical difficulties in re-crossing stents to gain access to a side branch are often challenging and sometimes prohibitive. Options for treating bifurcation disease are determined by several lesion characteristics, including the sizes of the two vessels of the bifurcation, the angle of takeoff of the branch vessel from the main vessel, the extent and severity of the disease of each vessel in the bifurcation, and the extent and severity of disease proximal and distal to the branch vessel. In our patient, the proximal aneurysmal segment in the LAD and the large diameter of the diagonal vessel prompted us to consider alternative approaches that would optimally treat the proximal disease in the LAD and maintain access to both the distal LAD and the DX branch. Conventional treatment with a single stent in the LAD, “crushing” a stent in the DX, LAD stenting with T-stenting of the DX, and “double barrel” or V-stenting, would have been possible. While each of these techniques has merit, we were concerned that they would not have provided optimal treatment of the proximal LAD. The technique we chose provided optimal treatment of the proximal LAD, as well as continuous access to both the DX and LAD vessels.¹¹ This technique also avoided areas where three layers of drug-eluting stent would overlap. Several technical challenges may occur using this technique. First, it may be difficult to pass stents through the previously deployed stent. While this was not an issue in this case, it may occur when using two wires and two monorail stents or balloons, impeding movement of wires and devices. Fortunately, this was not a problem in this case. One other potential concern with this technique involves the effect of the crimping procedure on the subsequent efficacy of drug elution. There is the possibility that aggressive manipulation of a drug-eluting stent will alter the integrity of the polymer coating, with subsequent failure to deliver appropriate amounts of drug. Stent and polymer coating deformation occcur to the side branch stent during the “crush” technique with satisfactory results following final kissing balloon angioplasty at the bifurcation. Whether the extent of stent and polymer deformation occurring during the technique reported here is comparable to that which occurs during the “crush” technique is uncertain. No other clinical or experimental data exist to address this concern. Long-term follow-up will be necessary to determine whether this concern is theoretical or real, and whether this technique represents a viable alternative for management of this complex lesion subset. bapplega@cwfubmc.edu

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