The “Proxis-Tornus” Technique for a Difficult-to-Cross Calcified Saphenous Vein Graft Lesion

Author Affiliations: From the Division of Cardiovascular Diseases, University of Texas Southwestern Medical Center, Dallas, Texas, and the *Dallas VA Medical Center, Dallas, Texas. Disclosures: Dr. Brilakis has received speaker honoraria from St. Jude Medical; Dr. Banerjee has received speaker honoraria from St. Jude Medical, Cordis Corporation and Medtronic, Inc. Manuscript submitted February 4, 2008, provisional acceptance given March 25, 2008, and accepted March 26, 2008. Address for correspondence: Emmanouil S. Brilakis, MD, PhD, Dallas VA Medical Center (111A), 4500 South Lancaster Road, Dallas, TX 75216. E-mail: esbrilakis@yahoo.com

_______________________________________________ ABSTRACT: Severely calcified lesions may occasionally be difficult to cross. We report a case of emergency percutaneous coronary intervention of a calcified saphenous vein graft lesion. We were unable to cross the lesion with a balloon despite using a 7 Fr guiding catheter, a buddy wire and the Tornus catheter, which was likely due to poor guide support. We describe successful crossing and treatment of the lesion by simultaneously using the Proxis proximal occlusion embolic protection device and the Tornus catheter.

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J INVASIVE CARDIOL 2008;20:E258–E261 Saphenous vein graft (SVG) lesions are usually friable and easy to cross with balloons and stents. Rarely, especially in old SVGs, severe calcification may make SVG lesions resistant to crossing with even the lowest-profile balloons. In such cases, additional techniques can be employed such as deep guide intubation,1–4 buddy wire,5 or plaque-modifying techniques such as excimer laser debulking,6 rotational atherectomy7 or Tornus catheter penetration (Asahi Intecc, Nagoya, Japan).8 The Proxis catheter (St. Jude Medical, Maple Grove, Minnesota) is a proximal embolic protection system that provides outcomes similar to those obtained with distal embolic protection in SVG interventions.9 It is deployed proximal to the target lesion before crossing, and the sealing balloon is inflated, interrupting antegrade flow while the target lesion is treated. Emboli released during intervention are subsequently retrieved by aspiration through the catheter before the sealing balloon is deflated.9 Apart from offering distal embolization protection, the Proxis device can also increase guide support through the combination of deep intubation and inflation of the sealing balloon, and therefore enhance the ability to deliver balloons or other interventional equipment to the lesion. The Tornus catheter is a wire-braided microcatheter designed to penetrate difficult-to-cross chronic total occlusions (CTOs) and severely calcified lesions.8,10 It consists of 8 stainless steel wires and is advanced by counterclockwise rotation crossing and modifying the lesion. We describe a case in which the isolated use of the Tornus catheter was unsuccessful, yet simultaneous use of the Proxis and Tornus catheters allowed crossing and successful treatment of a difficult-to-cross, severely calcific SVG lesion. Case Report. A 78-year-old male with a history of coronary artery bypass graft surgery at age 50 presented with rest angina and subsequently developed acute pulmonary edema and cardiogenic shock. Electrocardiography (ECG) demonstrated 2 mm ST-segment depressions in the lateral precordial leads. The patient was receiving warfarin for atrial fibrillation and his international normalized ratio was 3.4. He was emergently intubated and transferred to the cardiac catheterization laboratory. Recombinant factor VII was given prior to obtaining arterial and venous access. His initial systolic blood pressure was 75/36 mmHg. An intra-aortic balloon pump was inserted via the left femoral artery and unfractionated heparin (7,000 units intravenously) was administered. Coronary and graft angiography showed an occluded mid-right coronary artery (RCA), an occluded proximal left anterior descending artery (LAD), a severely diseased circumflex artery with antegrade flow, and a single sequential calcified SVG supplying the LAD, diagonal, ramus intermedius and the first obtuse marginal branch, with TIMI 1 flow and a severe proximal lesion (Figure 1). A decision was made to attempt high-risk percutaneous coronary intervention of the SVG lesion. The sequential SVG was engaged with a 7 Fr multipurpose guide catheter (Cordis Corp., Miami Lakes, Florida) that only provided moderate support. The lesion could not be crossed despite using several guidewires: Asahi soft (Abbott Vascular, Abbott Park, Illinois), Cougar LT (Medtronic, Inc., Santa Rosa, California) and BMW (Abbott Vascular). We eventually crossed the lesion with a Whisper guidewire (Abbott Vascular). We attempted to exchange the wire for a 5 mm Spider filter-based embolic protection device (eV3, Inc., Plymouth, Minnesota), but the Spider delivery catheter could not be advanced through the lesion. Similarly, the lesion could not be crossed with a Filterwire (Boston Scientific Corp., Natick, Massachusett). We were unable to cross the lesion with a 1.5 x 10 mm Sprinter balloon (Medtronic), a 1.5 x 12 mm Voyager balloon (Abbott Vascular), and a 1.5 x 15 mm Maverick balloon (Boston Scientific), despite using an Asahi soft wire (Abbott Vascular) as a “buddy-wire”. We also failed to cross the lesion using a 2.1 Fr Tornus catheter (Abbott Vascular), likely due to severe vessel calcification and inadequate guide catheter support. We then introduced a 7 Fr Proxis catheter through the 7 Fr guide (Figure 2) deeply into the SVG. The Proxis balloon was inflated and the lesion was then crossed using the 2.1 Fr Tornus catheter. We subsequently delivered a 1.5 x 15 mm Maverick balloon across the lesion, followed by a 2.0 x 13 mm Powersail balloon (Abbott Vascular), and a 2.5 x 15 mm Maverick balloon inflated up to 15 atm. A waist was seen initially in the balloons, but disappeared after higher-pressure inflations. We deployed a 3.5 x 16 mm Taxus (Boston Scientific) stent to the SVG lesion at 24 atm, and postdilated the stent with a 3.0 x 13 mm Powersail balloon at 28 atm and with a 3.5 x 15 mm Powersail balloon at 24 atm, obtaining a good angiographic result with mild residual stenosis (Figure 3) and TIMI 3 flow. Intravascular ultrasonography (IVUS) after stent deployment demonstrated adequate stent expansion and significant calcification (Figure 2D). Following the procedure, the lateral ST-segment depressions decreased. The patient required prolonged hospitalization in the cardiac intensive care unit. His clinical status gradually improved, with removal of the intra-aortic balloon pump 72 hours after the intervention. He was subsequently extubated and was discharged from the hospital angina-free 2 weeks later. Discussion. Our case demonstrates the combined use of the Proxis proximal protection device with a Tornus catheter to allow crossing of a severe SVG lesion with a coronary balloon. Most SVG lesions are friable and easy to cross, however, this lesion was very calcified, likely because bypass grafting was performed 28 years earlier. Several techniques have been proposed for coronary lesions that cannot be crossed with a balloon, such as: (a) using lower-profile balloons; (b) applying plaque modification with a laser,6 rotational atherectomy7 or the Tornus catheter;8 and (c) using techniques that increase guide support, such as using one or more buddy wires,5 using a larger diameter or a different-shaped guide catheter, using deep intubation of the guide into the target vessel,11 or using the “anchor” technique,12 whereby a balloon is inflated in the proximal side branch of the target vessel, anchoring the guide and offering extra support to deliver equipment. The above techniques can also be used in combination; for example, the “Anchor-Tornus technique” was recently described.10 In our case, several of the above techniques used in isolation were unsuccessful. We could not cross the lesion despite using the lowest-profile balloons available to us. An ACE fixed-wire balloon (Boston Scientific) has a very low profile and could be another option in such lesions.13 A laser was not available in our laboratory, and rotational atherectomy was considered a poor choice in an old SVG in a patient in cardiogenic shock, since distal embolization could be catastrophic. The 2.1 Fr Tornus catheter could not be advanced through the lesion and resulted in disengagement of the guide tip from the SVG ostium. We used a large (7 Fr) guide catheter from the beginning, and different guide catheter shapes could offer no advantage due to the inferior takeoff of the graft. Although the Tornus catheter initially failed to cross the lesion, it successfully crossed it when used together with the Proxis device, likely because the Proxis provided adequate support to the Tornus catheter to cross the lesion. Telescoping guide systems similar to the Proxis system have been successfully used to treat resistant native coronary artery lesions.1–4 The “Proxis-Tornus” strategy has limitations. There is a risk for proximal target vessel dissection by the tip of the Proxis device or the sealing balloon, especially in the presence of proximal or ostial SVG disease. Also, the deep Proxis intubation and the inflation of the sealing balloon can cause prolonged ischemia that could potentially lead to hemodynamic instability. In summary, we describe for the first time the combined use of two devices, the Proxis and the Tornus, to successfully cross and treat a severely calcified SVG lesion.

1. Bartorelli AL, Lavarra F, Trabattoni D, et al. Successful stent delivery with deep seating of 6 French guiding catheters in difficult coronary anatomy. Catheter Cardiovasc Interv 1999;48:279–284.
2. Stys AT, Lawson W, Brown D. Extreme coronary guide catheter support: Report of two cases of a novel telescopic guide catheter system. Catheter Cardiovasc Interv 2006;67:908–911.
3. Stys AT, Lawson W, Brown D. Extreme coronary guide catheter support: A case of a novel telescopic guide catheter system with a contralateral aortic wall support. J Invasive Cardiol 2007;19:E107–E110.
4. 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.
5. 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.
6. Fretz EB, Smith P, Hilton JD. Initial experience with a low profile, high energy excimer laser catheter for heavily calcified coronary lesion debulking: Parameters and results of first seven human case experiences. J Interv Cardiol 2001;14:433–437.
7. Ho PC, Leung C, Chan S. Blunt microdissection and rotational atherectomy: An effective combination for the resistant chronic total occlusion. J Invasive Cardiol 2006;18:E246–E249.
8. Tsuchikane E, Katoh O, Shimogami M, et al. First clinical experience of a novel penetration catheter for patients with severe coronary artery stenosis. Catheter Cardiovasc Interv 2005;65:368–373.
9. Mauri L, Cox D, Hermiller J, et al. The PROXIMAL trial: Proximal protection during saphenous vein graft intervention using the Proxis Embolic Protection System: A randomized, prospective, multicenter clinical trial. J Am Coll Cardiol 2007;50:1442–1449.
10. Kirtane AJ, Stone GW. The Anchor-Tornus technique: A novel approach to “uncrossable” chronic total occlusions. Catheter Cardiovasc Interv 2007;70:554–557.
11. Von Sohsten R, Oz R, Marone G, McCormick DJ. Deep intubation of 6 French guiding catheters for transradial coronary interventions. J Invasive Cardiol 1998;10:198–202.
12. 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.
13. Goldberg A, Klein R, Marmor A. Buddy wire, buddy balloon or better together. J Invasive Cardiol 2007;19:E363–E366.