The appropriate selection of the type of guide wire and its correct manipulation and positioning inside the coronary vessels are essential for successful percutaneous intervention (PCI). In most procedures, one guide wire is sufficient to allow the optimal deployment of balloons, catheters, stents, and other devices. The use of a second guide wire has became a standard procedure for the treatment of bifurcated lesions in order to maintain access to the side branches and to protect their integrity.1 Moreover, the use of a wire proximally placed to the stent struts has been proposed as a position marker for stent deployment in ostial lesions.2 In this paper, we present and discuss a series of other problematic conditions which occur during PCI procedures and which can be easily and successfully managed through the use of a “buddy” wire. Reduction of balloon slippage during angioplasty for in-stent restenosis. Balloon angioplasty represents an acceptable and commonly adopted treatment for in-stent restenosis. During the phase of balloon inflation, the occurrence of balloon slippage is very common (up to about 25% of cases of in-stent restenosis in the RESCUE trial; R. Albiero, personal communication at the Transcatheter Cardiovascular Therapeutics 2002), and may not only induce vessel dissections proximally or distally to the stented segment, but also cause an increase in procedural and fluoroscopy time. The use of devices specifically designed to avoid balloon slippage, such as the Cutting Balloon™ (Boston Scientific Corporation, Maple Grove, Minnesota), the latest FX MiniRAIL™ balloon (Guidant Corporation, Santa Clara, California), and the GRIP balloon (Acrostak Corporation, Winterthur, Switzerland), is effective, though quite expensive, and sometimes causes the need for additional balloons due to the limited availability of lengths and sizes. Moreover, these devices, especially the cutting balloon, are sometimes unsuccessful in their ability to reach the lesion due to their stiffness and bulky profile. In our experience with in-stent restenosis, the simple addition of a second guide wire alongside the first one used for the positioning of the balloon in the lesion, enhancing thefriction between the balloon surface and the restenotic tissue, results in a dramatic reduction in the occurrence of balloon slippage (Figure 1 shows an example of buddy wiring for angioplasty of in-stent restenosis on a proximal left anterior descending artery). In this particular setting, it is important to select a guide wire without hydrophilic coating as a buddy wire to maximize the stabilizing effect of the second guide wire on the balloon. Of course, it is worth noting that the use of a buddy wire together with a cutting balloon is contraindicated due to the risk of side blade-induced guide wire fracture. In our catheterization laboratory, the use of a buddy wire to enable the stabilization of the balloon within the lesion in procedures in which the balloon slippage had occurred during standard ballooning is widely acknowledged, and we are now comparing the procedural outcomes of angioplasty for in-stent restenosis by randomly assigning patients to either buddy wire or cutting balloon treatment. Stenting of ostial lesions or of vessels with difficult take-off. The achievement and maintenance of a good back-up provided by the guiding catheter are key in the success of each phase of a PCI procedure. The widespread use of large-lumen, small-sized (5–6 Fr) guiding catheters, and the increasing use of the radial approach for percutaneous procedures, may result in suboptimal support of the guiding catheter in a subgroup of PCI patients.Moreover, insufficient back-up of the guiding catheter frequently emerges during a complex procedure, and in these circumstances, shifting to a larger size or to a more supportive shape may be inopportune. In such situations (which most often occur during the treatment of ostial stenosis, lesions located in native coronary vessels, or in saphenous vein grafts with difficult take-off from the aorta), we have been able to successfully advance balloon catheters or stents through the introduction of a second guide wire alongside the first one after having failed to accomplish the procedure in the standard manner. Figure 2, for example, shows a case of buddy wiring used to accomplish a procedure in a lesion located at the distal anastomosis of a saphenous vein graft. PCI in coronary arteries with anomalous origin from the aorta is often challenging as well because of the low support usually provided by guiding catheters, which are not specifically designed for these rare conditions. The use of a buddy wire may enhance the stabilization of the guiding catheter and may help to accomplish procedures in such cases. Figure 3 demonstrates a case of successful stenting of an anomalous left circumflex coronary artery arising from the right sinus of Valsalva during an acute myocardial infarction. In the most challenging situations, it may be a good strategy to place a more supportive second guide wire (for example a BHW guide wire, from Guidant Corp., or a ChoICE PT® extra support guide wire from Boston Scientific Corp.) to advance the balloon/stent, leaving the first guide wire in situ as a buddy wire. Stenting of lesions located in vessels with proximal tortuosities/angulations. Lesions in vessels with significant tortuosities or sharp angulations are very challenging in PCI procedures because of the low back-up from the guiding catheter in supporting the advancement not only of balloons and stents, but also of the guide wire itself. In these situations, procedural success is highly dependent on the guide wire support, and the use of a buddy wire may greatly enhance the ability to achieve a good result. Indeed, when the distal advancement of the guide wire is difficult, it may be useful to leave the wire in place or in a side branch and proceed with a second wire (a more hydrophilic one would be better). This technique enables both the preservation of access to the vessel and the stabilization of the guiding catheter, thus providing a more efficient back-up. Moreover, tortuous vessels often end up straightened by the two wires, thus facilitating balloon/ stent advancement. A similar situation is encountered when it is necessary to deploy a stent through a coronary segment with a combination of calcification and a sharp bend. In this case, it is often impossible to advance the stent, even when using an extra support wire, mainly because of the flaring effect of the stent on the balloon which forces the stent against the calcified vessel wall. The presence of a second, or even a third, buddy wire to constrain the stent and act as a track, is often helpful in allowing the stent to pass through the calcified bend to reach the target lesion. Naturally, it is better to remove the buddy wire after stent positioning and before stent deployment in order to avoid difficulties during the removal of the trapped guide wire (especially if high-pressure inflation is necessary). Figure 4 demonstrates an example of buddy wiring for the stenting of a lesion located in an extremely ectasic and tortuous right coronary artery. Stenting of distal lesions. During stent implantation in distal lesions, the back-up provided by the guiding catheter is probably less important than the one coming from the guide wire. In cases of stent positioning failure, the commonly adopted strategy is to shift to a guide wire with higher support properties. However, in these cases as well, the simple addition of a second guide wire alongside the first one may help to quickly drive the stent down to the distal vessel (Figure 5 shows the successful use of a buddy wire to perform direct stenting of the distal segment of a right coronary artery with severe proximal tortuosity). Once the stent has been correctly placed, the buddy guide wire should be removed before stent inflation in order to avoid its trapping. Stenting of lesions located distally to a previously implanted stent. The crossing of stents through a previously implanted stent is often feasible without causing major difficulties. However, when the stent to be crossed is located in vessels with proximal or distal angulation/tortuosity, the friction between the stent struts may impede the advancement of the new stent. In this situation, the use of a second guide wire may enhance support, reduce angulations, and stabilize the guiding catheter, thus making stent crossing possible. Figure 6 shows a case in which the addition of a buddy wire allowed stent positioning in a lesion of the marginal branch through a previously implanted stent in the proximal circumflex, after having failed to cross with a single guide wire. Facilitation in the positioning of distal protection devices. The intrinsic nature of distal filter protection devices, which are very stiff and bulky, makes their positioning in the distal ends of the vessels very challenging, and sometimes impossible. It is difficult to achieve good alignment and sufficient back-up of the guiding catheter in saphenous vein grafts, in particular, but also in tortuous native coronary arteries. In these cases, placing a guide wire prior to deploying the filter helps in several ways: 1) The wire stabilizes the ostial positioning of the guiding catheter and facilitates its manipulation in order to improve its coaxiality with the proximal segment of the vessel; 2) the wire straightens the vessel and makes navigation of the filter easier; 3) since the wires tend to attract each other, the presence of a wire across the lesion often facilitates the passage of the filter, which is difficult to steer. It is always better to remove the buddy wire before stenting, if this is not done, the operator has to be absolutely certain to have inserted the stent over the filter wire. Indeed, deployment of the stent over the wrong wire when the filter is still opened, could result in the inability to remove the filter from the vessel. Figure 7 shows a case of buddy wiring for distal filter positioning in a saphenous vein graft. A peculiar situation is represented by distal protection during acute myocardial infarction, a condition in which the control of the culprit vessel has to be quickly gained and then securely maintained. For this purpose, it is helpful to cross the occlusive lesion with a normal guide wire to restore an anterograde flow enhancing the visualization of the distal vessel (clarifying its anatomy and size). Moreover, this maneuver facilitates the selection of the anti-embolic device and makes advancement of the filter guide wire easier and faster. Discussion The use of a second guide wire — or the so-called “buddy” wire — may be helpful in several situations during PCI. Compared to other tools used to resolve difficult situations encountered during PCI, the buddy wire has the advantage of being quick and easy to use. Apart from the well-known role it plays in protecting side branches of bifurcated lesions, the main advantages of using two wires are: 1) Stabilization of the balloon within the lesion in in-stent restenosis, where neointima characteristics make it difficult to hold the balloon in place, and slippage of the inflated balloon outside the stented segment is undesirable due to the potential risk of edge dissections; 2) stabilization of the guiding catheter at the ostium of a vessel, even in the event of suboptimal matching of the catheter and the coronary artery (ostial lesions, saphenous vein grafts, anomalous origin of native coronary arteries, etc.); 3) anatomical characteristics that impede the steering of devices inside the vessels (tortuosities, sharp bends, calcifications, distal lesions, previously implanted stents, etc.); 4) facilitation of distal protection device positioning. The placement of a second guide wire does not usually produce adverse effects, though caution is needed to avoid the risk of guide wire-induced distal spasm or endothelial damage. Moreover, high-pressure stent inflation must be avoided before wire removal due to the potential risk of buddy wire entrapment and/or fracture. In conclusion, in view of its simplicity, low cost, easy deliverability, and the fact that no major changes in PCI strategy are required (i.e., no changes in guiding catheter or stent/balloon), the buddy wire is a good and inexpensive option to improve the success rate of complex PCI procedures. Acknowledgements. The authors thank all of the nurses and technicians at our catheterization laboratory for their precious help in our daily practice and in the management of complex procedures. We also thank Dr. Bianca Maria Pepe for her help in the revision of this manuscript.
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