The Use of the X-Sizer‚Ñ¢ Transluminal Extraction Catheter as an Adjunct to Stenting of Occluded Saphenous Vein Grafts

Philip C. Strike, MD, Nicholas M. Robinson, MD, Duncan S. Dymond, MD
Philip C. Strike, MD, Nicholas M. Robinson, MD, Duncan S. Dymond, MD
Within a decade of surgery, half of all aortocoronary saphenous vein grafts (SVGs) are totally occluded or have severe atherosclerotic disease.1 Redo coronary artery bypass surgery (CABG) has higher mortality and morbidity than the first operation and provides less symptom relief.1 Balloon angioplasty for the treatment of SVG stenoses has been disappointing,2–5 although the use of stents has improved early and late results.1,6,7 Occluded SVGs have a high amount of thrombus and atherosclerotic debris and have a poorer outcome following angioplasty than patent focal lesions.1,8 Percutaneous intervention to saphenous vein grafts is becoming an increasingly large part of the work of the interventional cardiologist and new techniques to improve results must be constantly assessed. The X-Sizer™ transluminal extraction device (EndiCOR Medical Inc., San Clemente, California) removes thrombus and atherosclerotic debris from SVGs with a novel vacuum catheter. The device consists of a dual-lumen, hydrophilic-coated catheter. The inner lumen contains a hollow torque cable with a helical cutter housed within the distal tip. The cutter is rotated at about 2,100 rpm during use. The outer lumen of the catheter is the route by which debris are removed by vacuum (Figures 1 and 2). We report 3 cases where aggressive antiplatelet therapy (abciximab, aspirin and clopidogrel) in association with the physical removal of thrombus and atherosclerotic debris with the X-Sizer™ catheter allowed successful percutaneous revascularization of occluded SVGs. Case Report. Three patients (mean age, 63.3 years) were admitted with acute coronary syndromes (ACS) a mean of 9.7 years after CABG. All 3 subjects had recently occluded vein grafts thought to be responsible for their symptoms. All patients had been on aspirin since their bypass surgery and all received pre-treatment with clopidogrel 300 mg on the day prior to their diagnostic procedure followed by 75 mg once daily. All received a weight-adjusted dose of heparin at the time of intervention (70 U/kg). Patient #1. The first patient was a 71-year-old male with redo vein grafts 9 years previously to the left anterior descending (LAD) coronary artery and right coronary artery (RCA). He had undergone percutaneous transluminal coronary angioplasty and stent deployment to the RCA saphenous vein graft (SVG) 5 months previously for a recurrence of symptoms, with good result. Coronary angiography after admission with an ACS showed occlusion of this RCA SVG (Figure 3). The patient was treated with abciximab. Balloon support was used to pass the wire to the distal vessel. The X-Sizer™ catheter was then used to remove debris from the occluded SVG prior to any balloon inflation and stent deployment, significantly improving the angiographic appearance (Figure 4) prior to stent deployment with an excellent final result (Figure 5) without evidence of distal embolization. Patient #2. The second patient was a 64-year-old female who underwent CABG in 1989. She presented with ACS with diagnostic coronary angiography showing a newly occluded circumflex artery SVG (Figure 6). The patient was felt to be unsuitable for further CABG and her graft occlusion was treated percutaneously. She received pre-treatment with abciximab overnight pre-intervention. The occlusion was crossed with a guidewire with balloon support. The graft was treated with the X-Sizer™ device (Figure 7). Before treatment with the X-Sizer™ device, the distal vessel was reached by the contrast in 12 cardiac cycles. After treatment, the distal vessel was well opacified after just 1 cardiac cycle. Subsequently, stent deployment was performed with an excellent angiographic result (Figure 8). Patient #3. The third patient was a 55-year-old male with a history of CABG in 1993. He presented with ACS; subsequent coronary angiography showed occlusion of the RCA SVG at its origin (Figure 9). The patient was treated with abciximab prior to engagement with an 8 French multipurpose guide catheter. Using balloon support, a 0.014´´ high-torque floppy wire was passed to the distal vessel. This produced a dramatic improvement in lumen size within the SVG (Figure 10). Subsequent stent deployment was successful, with an excellent angiographic appearance. Discussion. These 3 cases demonstrate the efficacy of the X-Sizer™ extraction catheter system in the percutaneous treatment of occluded SVGs. In all cases, the TIMI flow was 0 pre-procedure, 1–2 peri-procedure and 3 post-procedure. There was no incidence of the “no reflow” phenomenon. Measurements of post-procedure CPK were not taken. Plain old balloon angioplasty (POBA) of SVGs has been disappointing, with poor short- and long-term results. The primary procedural success rate is low compared with native vessels, at 85–91% with a high subsequent incidence of restenosis, adverse clinical events and the need for further revascularization procedures.2–5 Freedom from myocardial infarction or repeat CABG at 1 and 5 years has been shown to be 77% and 53%, respectively.5 The results are worse the older the grafts are at the time of angioplasty.2,4,9 The use of stents in SVGs improves procedural outcome1,6,7 and restenosis rates compared with POBA.1 The use of stents has resulted in a decrease in death, myocardial infarction and repeat revascularization procedures compared with POBA.5,7 The angiographic restenosis rates vary from 17–51%,8,10,11 with higher rates of restenosis for restenotic lesions, smaller vessel size, ostial lesions, patients with diabetes mellitus and higher post-stent percent diameter stenosis.11 Occluded vein grafts present additional problems. There is a lower initial success rate, a higher incidence of procedural complications and increased incidence of restenosis compared with patent focal lesions.12,13 POBA in occluded vein grafts has very poor results, with a procedural success rate of 12,13 The complications of distal embolization and the “no reflow” phenomenon are increased in occluded SVG intervention.12 The substrate in occluded SVGs involves a high thrombus load and a large amount of atherosclerotic debris that can lead to distal embolization (so called “toothpasting”) after stent deployment. The outcome of intervention in the presence of an angiographically visible high thrombus load is worse than if no thrombus is seen.14 A recent retrospective examination15 of primary POBA versus primary stenting in acute SVG occlusion found a higher success rate and lower residual stenosis in the stent group, but a similar incidence of death and reinfarction. Various strategies have been advocated in SVG intervention to try and improve success rates. These include direct stenting without pre-dilation, suction/aspiration catheter devices such as the TEC catheter,9 temporary occlusion and aspiration systems,16 directional coronary atherectomy,17 excimer laser angioplasty,18 distal protection devices to trap embolized debris,19 covered stents,20 overnight urokinase infusions,13 prior use of systemic glycoprotein IIb/IIIa inhibitors before stenting21 and the use of locally delivered abciximab prior to intervention.22 Although abciximab has been shown to reduce the thrombus burden if given locally or systemically21,22 in saphenous vein grafts, it has no effect on the post-procedural CK-MB during vein graft PTCA.23 Despite improved procedural success and reduced distal embolization (2% versus 18%) with abciximab in the vein graft intervention arm of the EPIC trial, there was no difference in the 30-day and 6-month clinical outcomes between the groups.24 Abciximab improves outcomes in transluminal extraction atherectomy of occluded SVGs.25 It has been hypothesized that the heavy thrombus and atheroma burden found in diseased SVGs hampers drug penetration and efficacy;22 consequently, a combination of platelet inhibition and atherectomy may give superior results. The patients presented here were all treated with the X-Sizer™ device. There are 3 X-Sizer™ device sizes, with a distal tip diameter of 1.5 mm, 2.0 mm or 2.3 mm. The smallest size can be used with a 6 French guide catheter (as long as it has at least a 0.068´´ inner lumen). The middle and largest sizes require an 8 French guide catheter. Currently, the X-Sizer is an over-the-wire system. Our experience is that the device is best used with two operators, but is otherwise easy to use. Device preparation is straightforward and adds only 5–10 minutes to procedure time. The device is trackable and capable of crossing acute bends. Our aim with the device has been to remove soft atherosclerotic debris and thrombus rather than more fibrotic disease. We have not directly compared the X-Sizer™ device with the TEC catheter, but the latter requires larger groin sheaths and 9 or 10 French guide catheters. We have used our standard manual compression protocol for post-procedure femoral puncture site management with no problems. No additional compression or closure devices have been needed. It is encouraging that evolving strategies for SVG intervention are producing superior results. A recent review of outcome after SVG intervention showed a significantly improved 1-year event-free survival (70.7% vs. 59.1%) in patients treated between 1995 and 1998 compared with patients treated between 1990 and 1994.26 However, the incidence of major in-hospital complications, non-Q wave myocardial infarction and “no reflow” were similar. Over this time, there was an increased use of stents and glycoprotein IIb/IIIa inhibitors (although Acknowledgments. We would like to thank Dr. Rex Dawson and Dr. John Hogan for letting us use their patients in this report. The X-Sizer™ picture and schematic are courtesy of Endicor.
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