Prospective Randomized Trial of Thromboatherectomy With the X-Sizer in Native Coronary Arteries and Saphenous Vein Grafts - X-TRACT


X-TRACT was a randomized trial of the X-SIZER thromboatherectomy device in saphenous vein grafts (SVGs) and native arteries with thrombus.


Use of the thromboatherectomy X-SIZER device will reduce bailout need for glycoprotein (GP) IIb/IIIa inhibitor use, major cardiac events (MACE) at 30 days, and large myocardial infarctions (MIs) at 30 days.

Study Design

Study Design:

Patients Enrolled: 797
Mean Follow Up: One year
Mean Patient Age: Mean age 65 years
Female: 21
Mean Ejection Fraction: Forty-nine percent in X-SIZER patients versus 51% in placebo patients (p=NS)

Patient Populations:

≥1 SVG lesion or definite thrombus in a native coronary artery, and vessel successfully wired prior to randomization


Acute MI within 24 hours, elevated creatine phosphokinase or MB at time of intervention, left ventricular ejection fraction <30%, in-stent restenosis, thrombolysis in MI flow grade 0, isolated ostial lesion, or distal SVG anastomotic lesion

Primary Endpoints:

MACE at 30 days (death/MI/target vessel revascularization)

Secondary Endpoints:

Individual components of MACE at 30 days (death/MI/target vessel revascularization)

Drug/Procedures Used:

Patients were stratified prior to randomization by planned use of GP IIb/IIIa inhibitors. Patients were randomized to the X-SIZER thromboatherectomy device (n=400) or percutaneous coronary intervention (PCI) alone (n=397).

Principal Findings:

More patients randomized to the X-SIZER arm had thrombus present prior to the intervention (70% vs. 58%, p<0.001) and had a larger diameter stenosis (70% vs. 67%, p=0.01). There was no significant difference between the X-SIZER and placebo arms in frequency of SVG intervention (75% vs. 72%, p=NS), use of nonbailout GP IIb/IIIa inhibitors during the procedure (76% vs. 77%, p=NS), use of stents (98% vs. 97%, p=NS), or other baseline characteristics including age, gender, prior diabetes, or presenting diagnosis. Bailout use of GP IIb/IIIa inhibitors tended to occur less frequently in the X-SIZER arm (0.8% vs. 2.3%, p=0.09) in all patients and when restricted to patients who did not receive prebailout GP IIb/IIIa inhibitors (3.1% vs. 9.8%, p=0.06).

The rate of 30-day MACE (death/MI/target vessel revascularization) did not differ between the two arms (16.8% X-SIZER vs. 17.1% placebo, p=NS). There was also no difference in MACE at one year (31.3% vs. 28.2%, p=0.35).

Large MI (Q-wave or creatine kinase-MB >8 x upper limits of normal) by 30 days occurred less frequently in the X-SIZER arm compared with the placebo arm (5.5% vs. 9.6%, p=0.03). In an analysis stratified by presence of thrombus (n=450), there was a nonsignificant 60% reduction in the frequency of large MI by 30 days (4.7% vs. 9.9%, p=0.04).


Among patients with diseased SVGs or thrombotic native arteries, treatment with the X-SIZER thromboatherectomy device was not associated with a reduction in the primary endpoint of 30-day MACE compared with stenting alone. Thrombectomy was associated with a reduction in large MIs at both 30 days and one year (trend).

MACE rates in the X-TRACT trial were higher than rates seen in the SAFER trial of a distal embolization device used in SVGs, which showed a 9% MACE rate.


Stone GW, Cox DA, Babb J, et al. Prospective, randomized evaluation of thrombectomy prior to percutaneous intervention in diseased saphenous vein grafts and thrombus-containing coronary arteries. J Am Coll Cardiol 2003;42:2007–13.

Presented at the American Heart Association Annual Scientific Sessions, November 2002, by Gregg W. Stone, M.D.

Clinical Topics: Cardiac Surgery, Heart Failure and Cardiomyopathies, Invasive Cardiovascular Angiography and Intervention, Aortic Surgery, Cardiac Surgery and Heart Failure, Heart Failure and Cardiac Biomarkers

Keywords: Myocardial Infarction, Thrombosis, Thrombectomy, Saphenous Vein, Creatine Kinase, MB Form, Constriction, Pathologic, Diabetes Mellitus, Platelet Membrane Glycoprotein IIb, Stents, Percutaneous Coronary Intervention, Platelet Glycoprotein GPIIb-IIIa Complex

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