X-SIZER in Acute Myocardial Infarction Patients for Negligible Embolization and Optimal ST Resolution - X-AMINE ST


The goal of the X-AMINE ST trial was to evaluate whether treatment with the X-SIZER thrombectomy device as an adjunctive to percutaneous coronary intervention (PCI) with stenting was associated with an increase in ST resolution among patients with acute myocardial infarction (AMI).


Adjunctive treatment with thrombectomy will be associated with an improvement in the primary endpoint of ST resolution compared with PCI alone in patients with AMI.

Study Design

Study Design:

Patients Enrolled: 201
Mean Follow Up: 6 months
Mean Patient Age: mean 62 years
Female: 25%

Patient Populations:

AMI within 12 hours with thrombus and/or high-risk of distal embolization; ST elevation ≥2 mm in ≥2 contiguous leads; Killip class <III; TIMI flow grade 0 or 1; target vessel revascularization ≥2.5 mm; and no thrombolysis


Left bundle branch block; or ostial or saphenous vein graft lesions

Primary Endpoints:

ST-segment resolution

Secondary Endpoints:

ST resolution >50%; TIMI frame count; myocardial blush grade; slow flow, no reflow or distal embolization; and MACE at six months

Drug/Procedures Used:

Patients were randomized to thrombectomy with stenting (n=100) or stenting alone (n=101). Use of glycoprotein (GP) IIb/IIIa inhibitors and direct stenting was left to the discretion of the investigator.

Principal Findings:

Thrombus was removed in 97% of patients in the thrombectomy arm. Use of GP IIb/IIIa inhibitors did not differ between treatment arms (55% for thrombectomy vs. 65% for control), but direct stenting was used more frequently in the thrombectomy arm (60% vs. 34%, p<0.001).

There was no difference in TIMI flow grade 3 (95.9% vs. 89.0%, p=NS) or TIMI frame count (22.6 frames vs. 25.1 frames, p=NS) between the thrombectomy arm and the control arm, respectively, but distal embolization (2.1% vs. 10.0%, p=0.033) and slow or no reflow (4.1% vs. 16.0%, p=0.012) occurred less frequently in the thrombectomy arm.

The primary endpoint of median ST resolution was greater in the thrombectomy arm (7.50 mm vs. 4.90 mm, p=0.033), as was resolution score (percent resolution from baseline; 66% vs. 56%, p=0.03) and percent of patients with ST resolution >50% (67.8% vs. 52.6%, p=0.037). Major adverse cardiac events (MACE) as 6 months was similar between the treatment arms (13% each, p=NS), as was mortality (6% vs. 4%, p=NS).


Among patients with AMI undergoing PCI with stenting, adjunctive treatment with thrombectomy was associated with an improvement in the primary endpoint of myocardial perfusion, as assessed by ST-segment resolution compared with PCI alone. While the present study was underpowered to detect a difference in clinical outcomes, prior studies have shown an association between improved myocardial perfusion and clinical outcomes. Due to the nature of the trial design, treatment with the X-SIZER thrombectomy device was not blinded, a limitation of the trial.


Lefèvre T, et al. X-Sizer for Thrombectomy in Acute Myocardial Infarction Improves ST-Segment Resolution. J Am Coll Cardiol 2005;46:246–52.

Presented at the 2003 Transcatheter Cardiovascular Therapeutics conference, by Thierry Lefevre, MD

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, Research Personnel, Platelet Membrane Glycoprotein IIb, Stents, Percutaneous Coronary Intervention, Platelet Glycoprotein GPIIb-IIIa Complex

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