Adjunctive Balloon Angioplasty Following Coronary Atherectomy Study - ABACAS

Description:

IVUS-guided directional atherectomy with or without balloon angioplasty for restenosis.

Hypothesis:

To evaluate whether aggressive debulking with IVUS-guided DCA followed by adjunctive balloon dilatation reduces restenosis.

Study Design

Study Design:

Patients Screened: Not given
Patients Enrolled: 214

Patient Populations:

Native coronary vessel
De novo or restenotic lesion
Reference vessel > 2.7 mm
Lesion suitable for DCA

Primary Endpoints:

Target vessel revascularization at 6 months; minimum luminal diameter at 6 months.

Drug/Procedures Used:

IVUS-guided optimal directional atherectomy (DCA) alone or with adjunctive PTCA.

Principal Findings:

A total of 108 patients were randomized to optimal DCA with adjunctive angioplasty, and 106 patients were randomized to optimal DCA alone. Before randomization, sufficient debulking was performed to create a plaque cross sectional area of 46% in both groups.

In hospital, one patient experienced a q-wave myocardial infarction; there were no deaths or CABG procedures. There 1 non-cardiac death and 1 CABG in the follow-up phase, and target vessel revascularization rate at 6 months was 17%.

QCA results showed no difference between the two groups with respect to the pre DCA minimum lumen diameter (112 ± 0.47 for DCA alone vs 1.10 ± 0.42 mm for DCA with PTCA). There was a significant difference between the two groups after the procedure (2.51 ± 0.52 for DCA alone vs. 2.73 ± 0.55 mm for DCA with PTCA, p = 0.03).

At six months, however, there was no difference in MLD in the two groups (1.87 ± 0.46 for DCA alone vs 1.91 ± 0.18 for DCA with PTCA).

Restenosis rates at six months were not significantly different between the two groups (23.6% for DCA with adjunctive balloon angioplasty vs 19.6% for DCA alone).

To elucidate the influence of deep wall resection and adjunctive balloon on the restenosis rates, histological and angiographic studies were performed. A total of 194 eligible patients were divided into four subgroups according to the presence of subintimal resection and need for adjunctive balloon dilatation. The DCA with intimal resection (D/I) group contained 38 patients, the DCA with subintimal resection (D/S) group 57 patients, the DCA/balloon with intimal resection (D/I/B) group 48 patients, and DCA/balloon with subintimal resection (D/S/B) group 53 patients. QCA analysis revealed more late loss and a higher loss index for the D/I/B group than the others; however, these differences were not statistically significant. The restenosis rate in the D/I/B group was significantly higher than the other groups (D/I: 13.9%, D/S: 17.6%, D/I/B: 34.8%, D/S/B: 12.0%) (p < 0.05).

In 39 patients, prospective serial IVUS was performed at pre and post-procedure, and at 3, 6, and 12-month follow-up. Vessel area increased gradually through the follow-up period. Plaque area increased rapidly at 3 months, with minimal increases thereafter. As the result, lumen area decreased by 6 months but subsequently plateaued through 12 months.

Interpretation:

Adjunctive balloon dilatation improved acute angiographic results, but was not associated with better long-term results. Adjunctive balloon following DCA without subintimal resection increases the likelihood of restenosis. IVUS-guided complete removal of atheroma without adjunctive balloon may be the best strategy for DCA. Long-term vascular response after directional atherectomy consists of early rapid and late slow neointimal proliferation and gradual compensatory enlargement of the vessel.

References:

1. J Am Coll Cardiol 1997;29:281A. Preliminary results
2. J Am Coll Cardiol 1997;29:68A. Initial and long-term results
3. J Am Coll Cardiol 1998;31:225A. Preliminary results; subgroup analysis

Clinical Topics: Cardiac Surgery, Invasive Cardiovascular Angiography and Intervention, Atherosclerotic Disease (CAD/PAD), Aortic Surgery, Interventions and Coronary Artery Disease

Keywords: Coronary Artery Disease, Myocardial Infarction, Plaque, Atherosclerotic, Atherectomy, Coronary, Dilatation, Angioplasty, Balloon, Coronary


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