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

Description:

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).

Hypothesis:

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

Exclusions:

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).

Interpretation:

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.

References:

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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