Buried Wire Technique: Enhancing Support Method for Complex Percutaneous Interventions and Stenting

Case 1. A 63-year-old female with a history of hypertension, dyslipidemia, and an extensive anterior wall myocardial infarction (2003) presented with unstable angina accompanied by a troponin rise and mild inferior ischemic ST-T-wave changes on electrocardiography. A persantine-thallium scan revealed a left ventricular ejection fraction of 25% with an extensive anterior scar and severe inferior and posterior ischemia. Diagnostic angiography showed 99% mid left anterior descending (LAD) and distal circumflex artery occlusion. The LAD territory was known to be scarred. The dominant right coronary artery (RCA) originating from the left coronary sinus (imaged using a multipurpose catheter) had 90% diffuse stenosis involving the proximal and mid portions of the RCA. We attempted to use numerous guide catheters, but none adequately fit. Reluctantly, we used a multipurpose 6 Fr guide catheter, which provided very little support and could not be positioned coaxially with the ostium of the RCA. Two 0.014 inch Whisper guidewires (Guidant Corp., Diegem, Belgium) were advanced across the lesions to the distal RCA (Figure 1A). After predilating the diseased segments in the mid and distal portions of the RCA using a 2.5 x 20 mm Maverick^® balloon (Boston Scientific), we attempted to deploy a 2.75 x 32 mm Taxus^® (Boston Scientific) stent in the mid RCA lesion. The stent was unable to be advanced into the distal lesion due to inadequate guide catheter support. Hence, it was deployed in the proximal lesion with high pressure (16 atmospheres) while leaving the 1 Whisper wire buried under the stent struts (Figure 1B). Next, we advanced the primary (“unburied”) Whisper wire into the posterior left ventricular branch and advanced a new (third) Hi-Torque Balance “buddy wire” (Guidant) into the posterior descending branch. A second Taxus stent (2.75 x 16 mm) was deployed in the mid RCA lesion (Figure 1C) with satisfactory results (Figure 1D).

Case 2. A 48-year-old male with a history of a previous anterior wall myocardial infarction in 2003 that was treated with stenting of his LAD and left main coronary arteries presented to the emergency room with an infero-posterior wall ST-elevation myocardial infarction. Coronary angiography revealed patent stents in the left main and LAD and no significant disease in his left coronary system. His right coronary artery showed marked proximal ectasia and thrombotic occlusion of the distal RCA. Underestimating the vessel tortuosity, a 6 Fr Judkins Right-4 guide catheter was selected. A Whisper wire was advanced to the distal RCA and PDA branch (Figure 2A). After a few high-pressure dilatations (Figure 2B) using a Maverick 2.5 x 15 mm balloon, a secondary Whisper 0.014 inch “buddy wire” was inserted in the PDA (Figure 2B). We were not able to advance a 2.5 x 15 mm MicroDriver stent (Medtronic, Inc., Minneapolis, Minnesota) into the distal RCA lesion, so it was deployed in the angulated stenosed segment of the mid-distal RCA. The secondary Whisper “buddy wire” was intentionally left buried under the deployed stent struts and not withdrawn prior to stent deployment (Figure 2C). Postdilatation of the MicroDriver stent was accomplished using a 3 x 8 mm Quantum™ balloon (Boston Scientific). With the buried Whisper wire anchoring the guide catheter, it was feasible to advance a 2.75 x 18 mm MicroDriver stent into the more distal RCA lesion just proximal to the PDA lesion and deploy the stent with 16 atmospheres (Figure 2D). Now the secondary Whisper wire was buried under 2 separate stents. We eventually deployed the third MicroDriver 2.5 x 8 mm stent into a 90% stenosis in the proximal PDA lesion and removed the “buried” Whisper wire, with satisfactory final PCI results (Figure 2E).

Discussion. Stenting from proximal to distal segments while burying a guidewire under the struts of the proximal stent is a simple way to facilitate challenging distal stent delivery, especially in cases where optimal guide catheter support is lacking. With currently available stent design, it is extremely rare to encounter difficulty in deploying a distal stent via a more proximal one. Burying selected wire types under high-pressure, fully deployed stents does not result in wire entrapment or any other clinical problems. The authors have extensive experience using Whisper and Balance wires for that purpose. Some operators believe that hydrophilic-coated wires, like the Whisper, should not be buried under stents, or even be used for side branch protection during bifurcation stenting. This has not been our experience. Moreover, we also encountered several cases in which other wires (both hydrophilic-coated and uncoated) have been buried under stents or even between two overlapping stents, and were removed inadvertently. However, operators should be cautioned to avoid burying “buddy wires” between two stents or under a stent in a vessel with heavy subintimal calcification. In those circumstances, wire entrapment is more likely to occur.
Removal of the buried wire should be done cautiously under fluoroscopic guidance to avoid inadvertent guide catheter forward movement that can result in coronary injury. In cases of significant resistance to the “buried wire” removal at the end of the procedure, it is advisable to withdraw the guide catheter and the buried wire as one unit. The wire can be secured to the guide catheter by locking a rotating device on the wire adjacent to the Y-connector valve.
The concern regarding wire entrapment or tear, stent integrity, and microembolization of wire coating are valid and need to be addressed. Although these potential problems have not translated into any clinical events, they should be further investigated in vitro and in vivo.

Conclusion. Even in the event of insufficient guide catheter support, complex multilesion stenting can be executed from proximal to distal segments, while leaving a “buddy wire” buried under the struts of the fully deployed proximal stent. The “buried secondary (buddy) wire” method is easy to master and does not result in excessive incremental costs.

References

1. Takahashi S, Saito S, Tanaka S, et al. New method to increase a backup support of a 6 French guiding coronary catheter. Catheter Cardiovasc Interv 2004;63:452–456.
2. Li SS, Cheng CW. Coronary angioplasty on an impassable calcified stenosis using a buddy balloon technique. Catheter Cardiovasc Interv 2004;62:35–37.
3. Burzotta F, Trani C, Mazzari MA, et al. Use of a second buddy wire during percutaneous coronary interventions: A simple solution for some challenging situations. J Invasive Cardiol 2005;17:171–174.
4. Dana A, Barbeau GR. The use of multiple “buddies” during transradial angioplasty in a complex calcified coronary tree. Catheter Cardiovasc Interv 2006;67:396–399.
5. Fujita S, Tamai H, Kyo E, et al. New technique for superior guiding catheter support during advancement of a balloon in coronary angioplasty: The anchor technique. Catheter Cardiovasc Interv 2003;59:482–488.
6. Hirokami M, Saito S, Muto H. Anchoring technique to improve guiding catheter support in coronary angioplasty of chronic total occlusions. Catheter Cardiovasc Interv 2006;67:366–371.