Proximal Protection During Saphenous Vein Graft Intervention - PROXIMAL

Description:

The goal of the study was to evaluate treatment with a proximal protection device compared with use of a distal protection device among patients undergoing percutaneous intervention of saphenous vein grafts (SVGs).

Hypothesis:

Use of a proximal protection device will be noninferior to use of a distal protection device with respect to 30-day major adverse cardiac events (MACE) among patients undergoing intervention of SVGs.

Study Design

Study Design:

Patients Enrolled: 594
Mean Follow Up: 30 days
Mean Patient Age: Mean age 70 years
Female: 15
Mean Ejection Fraction: Mean 48%

Patient Populations:

Normal CK/CK-MB; lesion in up to 2 SVGs ≥50% but <100%; TIMI flow grade ≥1; and device landing zone reference vessel diameter 3.0-5.0 mm

Exclusions:

MI within 24 hours; cardiac surgery within 60 days; lesion within 5 mm of proximal anastomotic site; left ventricular ejection fraction <20%; more than two native lesions to be treated; or more than two SVGs to be treated

Primary Endpoints:

Noninferiority of MACE at 30 days, defined as death, MI (creatine kinase [CK]-MB ≥3x upper limit of normal), urgent coronary artery bypass grafting, or TVR

Drug/Procedures Used:

Patients were randomized to: 1) use of the Proxis proximal protection device (n=294), with use of the FilterWire or GuardWire distal protection device when the proximal device cannot be used, such as in the setting of proximal lesions, or 2) use of the distal protection device (FilterWire or GuardWire) (n=300), with no protection when a distal device cannot be used, such as in the setting of distal lesions. Randomization was stratified by glycoprotein (GP) IIb/IIIa inhibitor use. An additional 117 patients were treated with the proximal device in a roll-in phase.

Principal Findings:

Baseline characteristics were similar between groups, with 44% diabetics, 60% having had a prior myocardial infarction (MI), and 76% having class III or IV angina. GP IIb/IIIa inhibitors were used in 42% of patients. In the proximal protection group, SVG target location was the right coronary artery in 41% of interventions, circumflex in 36%, and left anterior descending in 23%, which differed from the control group slightly (38%, 45%, and 17%, respectively). In patients randomized to the proximal protection group, proximal protection was used in 82% of patients, distal protection was used in 16%, and no protection in 2%. In the control group, distal protection was used in 74% and no protection in 26%.

The primary endpoint of MACE at 30 days met the criteria for noninferiority (9.2% for the proximal protection group vs. 10.0% for the distal protection group, p=0.0061 for noninferiority, p=0.78 for superiority). There were no significant differences in the components of MACE, including death (0.7% vs. 1.0%, respectively), Q-wave MI (0.7% vs. 1.7%), non-Q-wave MI (7.9% vs. 6.4%), or target vessel revascularization (TVR) (0% vs. 1.0%). In an "as-treated" analysis, the 30-day MACE rate was 7.1% for proximal protection, 11.7% for distal protection, and 10.0% for no protection. Among the subgroup of lesions amenable to either proximal or distal protection (e.g., lesions in the mid section of the SVG), 30-day MACE trended lower in the proximal protection group compared with the distal protection group (6.2% vs. 11.2%, p=0.089).

Interpretation:

Among patients undergoing percutaneous intervention of SVGs, use of the Proxis proximal protection device was noninferior with respect to 30-day MACE compared with use of a distal protection device.

By design, distal protection devices are not possible to use in SVGs with a very proximal lesion location. Additionally, distal protection devices cannot protect against embolization that occurs during lesion crossing. While the trial was designed for noninferiority, there was a trend toward lower rates of MACE among the subgroup of patients whose lesions could be treated with either a proximal or distal protection. However, larger studies would be needed to fully evaluate superiority, as the present trial was designed to assess noninferiority. The Proxis device may provide an additional option for lesions that are not amenable to use of a distal protection device.

References:

Mauri L, et al. The PROXIMAL Trial: Proximal Protection During Saphenous Vein Graft Intervention Using the Proxis Embolic Protection System. J Am Coll Cardiol 2007;50:1442–9.

Presented by Dr. Campbell D.K. Rogers at TCT 2005, Washington, DC.

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

Keywords: Myocardial Infarction, Saphenous Vein, Coronary Vessels, Angioplasty, Balloon, Coronary, Diabetes Mellitus, Platelet Membrane Glycoprotein IIb, Stents


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