Chronic total occlusion (CTO) is always a challenge to the interventional cardiologist. The successful recanalization rate is only about 50–70%.1–5 Guidewires always prefer to go to the channel that has the lowest resistance. As a consequence, selective guidewire canalization of sidebranches coming out just before the occlusion site or repeated selection of a false channel that has been erroneously created are commonly encountered during the procedure. These phenomenan significantly prolong the procedure time and lower the success rate. This problem may be solved by deliberately blocking the sidebranch or the false lumen by putting in a pioneer guidewire while using another wire (crossing wire) to cross the CTO. Case Report. A 58-year-old man suffered from diabetes mellitus and hypercholesterolemia as the cardiovascular risk factors. He also had known coronary artery disease with history of percutaneous coronary intervention (PCI) approximately 4 years prior. Balloon angioplasty was performed to open up the chronic total occlusion in the mid left anterior descending (LAD) coronary artery at that time. Recently, he presented again with crescendo angina. Resting electrocardiogram showed no significant ischemic change. Reassessment coronary angiography revealed a distal left main artery 40% tubular lesion. The entire LAD and left circumflex (LCX) arteries were diffusely diseased without critical stenoses. The entire right coronary artery (RCA) was also diffusely diseased. The RCA divided into the postero-lateral branch (PLB) and the posterior descending artery (PDA) at the crux. The distal RCA had a 90% bifurcation stenosis that involved both the PLB and PDA origins. The PDA was subtotally blocked in the proximal course. There was a small sidebranch coming out just before the occlusion site in the PDA (Figure 1). We decided to perform an ad hoc revascularization procedure. The initial strategy was to double-wire the bifurcation lesion. A Choice-PT wire (Boston Scientific/Scimed, Inc., Maple Grove, Minnesota) was positioned in the PLB while another Choice-PT wire was attempted in the PDA. Unfortunately, the PDA wire repeatedly selected the sidebranch despite multiple alterations of the wire tip curve. It simply could not cross the lesion and flipped into the sidebranch on every attempt (Figure 2). It is very crucial to have a wire in the PDA proper; otherwise, balloon dilatation in the sidebranch will completely close off the PDA. After a short trial period of 15 minutes, the Choice-PT wire was intentionally left in the sidebranch (Figure 3) and a Cross-it wire (Guidant Corporation, Temecula, California) was used; it crossed the total occlusion in the PDA without much difficulty. Therefore, there were 3 wires left in the RCA system simultaneously (Figure 4). The second Choice-PT wire (pioneer wire) was then removed (Figure 5) and the PCI procedure proceeded in the usual manner. The PDA and PLB were sequentially dilated with a 2.5 mm balloon (Figures 6 and 7). The distal RCA lesion was stented across the PLB origin using a 3.0 x 15 mm Tsunami stent (Terumo Corporation) deployed at 14 atmospheres. A good angiographic result was obtained (Figure 8). The patient was seen at 4 weeks in the outpatient clinic without any clinical events. Discussion. Placing a guidewire through a CTO is a prerequisite for subsequent intervention. Various wire materials and designs, such as hydrophilic wires,6 stiff wires,7 the Magnum wire (Schneider, Zurich, Switzerland)8 and even laser wires,9 are currently used with considerable success. Various strategies, such as provision of strong guide catheter support or assembly of a guidewire and over-the-wire balloon catheter system, are commonly used in the treatment of CTO. Despite these technological advances, CTO angioplasty is still associated with relatively high failure and complication rates.10,11 The difficulty of recanalizing a CTO is further aggravated with the presence of a sidebranch just before the occlusion or a false channel that has been carelessly inflicted. This case report describes a simple method by occupying the sidebranch or the false channel by a pioneer guidewire and then using a crossing wire to cross the CTO. The advantage of a pioneer wire is four-fold. First, it blocks the lumen of the undesired channel and thus increases the resistance of these channels. As a result, the difference in impedance between the desired and undesired channel is narrowed down so that the crossing wire has a better chance of traversing the CTO. Second, the pioneer wire acts as a road map to guide the direction of the crossing wire, by which the amount of contrast used can be minimized. Third, the prolonged wire manipulation at the occlusion site can sometimes cause plaque shift and threaten the sidebranch ostium, which is now protected by the pioneer wire. Last, the simultaneous presence of the pioneer wire can provide some support to the crossing wire. We have adopted this strategy in several cases of CTO in which conventional techniques have failed. In these cases, the undesired channel was either an antegrade bridging collateral or a false lumen caused by the operator. All cases eventually ended with success. We feel that this method significantly facilitates the CTO angioplasty procedure and reduces radiation exposure. Conclusion. In the treatment of a CTO with a sidebranch or a false channel, a simple strategy of positioning a pioneer wire in the undesired channel while using another crossing wire to negotiate the lesion may shorten the procedure time and increase the recanalization rate.
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