Fracture of a Coronary Guidewire During Graft Thrombectomy With the X-Sizer Device


Carlos Cafri, MD, G. Rosenstein, MD, R. Ilia, MD

ABSTRACT: We present the first case reported of fracture of a coronary guidewire during thrombectomy of a massive thrombus in a recently occluded coronary bypass graft with the recently developed atherectomy catheter X-Sizer. The thrombus was successfully aspirated without distal embolisation and the guidewire fragment was trapped in the graft after covering with a coronary stent. Possible reasons for this unusual complication of X-Sizer are discussed.

J INVAS CARDIOL 2004;16:263–265
Key words: guidewire fracture, angioplasty complications, thrombectomy

Percutaneous coronary intervention (PCI) to thrombus-containing lesions is associated with a high risk of periprocedural complications. Distal embolism, no reflow and abrupt closure develop frequently and are associated with a high rate of myocardial infarction (MI) and mortality.1

The treatment of this type of lesion includes pharmacological measures and mechanical devices. However, the most appropriate strategy has yet to be established. Recently, the X-Sizer device has been added to the arsenal of treatments available for thrombotic lesions. This is a new atherectomy catheter designed to extract atherosclerotic material and thrombus from coronary vessels. The initial experience with this tool appears to be favorable but it is still in a period of evaluation.2–5 The clinical benefit should be more clearly established and the associated complications further recognized. We report the first case of guidewire fracture associated with the use of the X-Sizer device during PCI to a coronary graft.

Case Report. An 86-year-old male patient was hospitalized with non ST-elevation myocardial infarction and referred for heart catheterization. He had a long history of coronary artery disease, having suffered an inferior wall MI 20 years previously and underwent coronary bypass graft surgery 10 years previously. Five years prior to the current admission, he was catheterized. The internal mammary artery graft (IMA) to the left anterior descending artery (LAD) as well as the saphenous vein grafts (SVG) to the posterior descending artery (PDA) and the diagonal branch (D1) were patent. A saphenous vein graft to the obtuse marginal branch was found occluded. He was treated conservatively and was fine until a week before the current admission. He developed unstable angina and was hospitalized with prolonged chest pain at rest, with new inverted T waves in the precordial and inferior leads of the electrocardiogram. The troponin I level was elevated ( 2 mcg/ml ; normal value: < 0.7 mcg/ml) and a non Q-wave MI was diagnosed. He had recurrent rest angina despite full medical treatment and underwent heart catheterization. Complete occlusion of the proximal LAD and right coronary artery (RCA) as well as severe stenosis of the left main supplying a large left circumflex artery (CX) were demonstrated. The IMA and SVG to PDA were patent.

The SVG to D1 was found to be occluded in its mid-portion by a large thrombotic mass (Figure 1). Despite the risky clinical and angiographic picture, redo coronary bypass grafting was considered not appropriate due to the advanced age of the patient and the potential for compromise of the patent IMA during the surgical procedure. It was decided to proceed with PCI to this graft and to perform thrombectomy with the X-Sizer catheter system due to the presence of thrombus and high risk of embolism. After the administration of unfractioned heparin and a bolus of eptifibatide, cannulation of the graft was performed with an 7 French Judkins right coronary guiding catheter (Cordis®). A floppy 300 cm coronary guidewire (ACS, Guidant®) was negotiated with some difficulties through the graft to the diagonal branch. A 1.5 mm. X-Sizer catheter (Endicor,® San Clemente, Calif.) was prepared and gently advanced through the length of the entire graft (Figure 2). An injection of dye demonstrated acceptable patency of the graft with good distal flow and the appropriate placement of the wire tip into the diagonal branch. During withdrawal of the catheter, we observed the simultaneous backwards movement of the wire. An attempt to advance the device over the wire failed, and the whole system was advanced simultaneously. Activation of the rotational cutter during the withdrawal did not help, the wire did not separate from the cutter and furthermore, a rotational movement of the wire was observed. It was concluded that the wire was stuck at the distal end of the device, probably in the spinning helicoidal cutter. An attempt to rotate the cutter in the reverse direction again produced a rotatory movement of the wire but did not release it. We decided to withdraw the device and the wire together into the guiding catheter. During this maneuver, it was noted that the distal 4 cm of the wire was left free in the mid-portion of the graft. It was decided not to attempt extraction of the wire remnant and a 33 mm x 3.5 mm stent (Biodyvsio, Biocompatibles Ltd®) was deployed, trapping the wire against the vein wall, covering almost all the length of the wire fragment and improving the lumen diameter of that portion of the graft (Figure 3). Due to technical reasons, intravascular ultrasound was not available to demonstrate good apposition of the stent and trapping of the wire. The final injection demonstrated good graft patency with normal distal flow. Residual thrombus was observed in the distal segment of the graft (Figure 4). The procedure was concluded. No clinical complications were observed and the patient was discharged in good condition. During a follow up period of six months, no additional acute cardiovascular events were registered.

Discussion. We have presented the first reported case of guidewire transection caused by the X-Sizer device. The X-Sizer catheter is designed to remove thrombus from coronary artery and saphenous venous graft lesions. It has atherectomy and thrombectomy capability, through the action of a helix cutter rotating at 2,100 rpm and a vacuum collection-chamber for aspiration of excised atheroma, thrombus and debris. It is compatible for use with 7–9 French guiding catheters and with 0.014 in. coronary guidewires.

Acceptable angiographic and clinical perfomance has been reported, based on data of multicenter registries.2–7 In addition, randomized assessment of the device in patients with acute coronary syndromes supports its efficacy in improving epicardial coronary artery flow and accelerating ST-segment resolution on the ECG, compared with conventional PCI alone.8

Despite these potential benefits of the X-Sizer, only small series of patients have been published to date, and knowledge about the limitations of the device is minimal. Inability to advance the catheter through tortuous lesions, failure in crossing the target lesion and failure to improve anterograde flow or provide a wide lumen, are some of the limitations described. In addition, complications including distal embolization, dissection and coronary perforation have been reported.5,7,9

To date, guidewire fracture has not been previously described as a complication of the X-Sizer device. Prior experience with rotational atherectomy (RA), also based on a spinning device, demonstrates that this complication is possible and suggests potential mechanisms.
Guidewire transection with RA has been described due to wire looping within the aorta during the treatment of ostial RCA stenosis, contact of the burr with the 2.2 cm long distal tip of the wire, or in cases of angled lesions, with wire kinking. In addition, placement of the wire tip in a small branch that does not allow rotation of the wire can produce in some circumstances entanglement and fracture.10–12

In our case, the mechanism of the fracture is not clear. The inability to advance or retract the device over the wire suggests that the wire was trapped in the device. The rotational movement of the wire during the activation of the X-Sizer and the fracture of the wire at the tip of the atherectomy catheter suggest that it was stuck in the helix cutter mechanism. The rotation of the distal segment of the wire without rotation of the proximal part probably led to transection of the wire.

The mechanism causing the wire to become entrapped in the device is not clear. The graft was not tortuous, but the possibility cannot be excluded that the wire was kinked during the manipulation of the guiding catheter or during the advance of the X-Sizer. In addition, the use of an ACS floppy wire without hydrophilic coating may have contributed to the entrapment of the wire into the spinning cutter. The use of an extra support wire has been recommended by the manufacturer to prevent wire kinking.

Conclusion. We conclude that transection of the coronary guidewire is a potential complication of thrombectomy when using the X-Sizer device. Operators should be aware of this possibility. Prevention of kinking of the wire through appropriate selection of cases and manipulation of the interventional tools, as well as the use of hydrophilic-coated and extra-support guidewires may help to avoid this rare complication.

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