Post-IntraCoronary Treatment Ultrasound Result Evaluation - PICTURE

Description:

Intracoronary ultrasound for predicting restenosis after PTCA.

Hypothesis:

To establish whether morphological features of the dilated segment, as assessed by ICUS after the procedure, are predictive of subsequent restenosis.

Study Design

Study Design:

Patients Screened: 200
Patients Enrolled: 154
Mean Follow Up: 6 months
Mean Patient Age: 57
Female: 19.8

Patient Populations:

Successful PTCA of a single coronary artery, defined as a decrease of greater or equal to 30% in angiographic diameter stenosis after PTCA, a residual diameter stenosis < 50% (by visual assessment), and normal blood flow in the dilated artery (TIMI grade 3).
Target vessel reference diameter greater than or equal to 2.5mm.

Exclusions:

Prior PTCA at the same site.
Acute myocardial infarction < 2 weeks before PTCA.
Prominent coronary spasm.
Vessel tortuosity proximal to the segment of interest, precluding the passage of the ICUS catheter.

Primary Endpoints:

Angiographic outcome at 6 months.

Drug/Procedures Used:

All studies were performed with three mechanical, single-element, 30-MHz systems: (1) the Insight system (Cardiovascular Imaging Systems Inc) using 4.3F catheters; (2) the Intrasound system (Du-MED) using 4.1F catheters; and (3) the Boston Scientific system using 3.5F catheters with a Hewlett-Packard ICUS console.

Principal Findings:

ICUS imaging was performed after PTCA in 200 patients. The PTCA operator did not accept the angiographic appearance of the lesion after completion of the ICUS study in 46 patients because early loss of initial result (< 30 minutes) occurred during the ICUS study. In 35 of these cases, a second ICUS study was performed after additional balloon inflations.

A total of 164 patients returned for repeat angiography within 6 months. An acceptable ICUS examination was available for 170 lesions in 154 patients.

There was little late loss at follow-up (average of 0.17 +/- 0.51 mm), but otherwise the results were as expected for balloon angioplasty.

The overall incidence of a greater or equal to 50% diameter stenosis at follow-up (categorical restenosis) was 29.4%.

Quantitative ICUS parameters were weakly but significantly related to follow-up minimal luminal diameter on quantitative coronary angiography (lumen area: R² = .36, P = .0001; vessel area: R² = .29, P = .0002; plaque area: R² = -.18, P = .021; percent obstruction: R² = -.15, P = .05), but categorical restenosis was not significantly related to these parameters (P = .63, .77, .38, and .08, respectively).

No significant relationship with restenosis was found for ICUS parameters of plaque morphology or predefined types of vessel wall disruptions.

Interpretation:

Qualitative ICUS parameters after PTCA did not predict restenosis. A larger lumen and vessel area and a smaller plaque area by ICUS were associated with a larger angiographic minimal lumen diameter at follow-up, but these parameters were not significantly related to categorical restenosis.

The investigators concluded that after angiographically and clinically successful balloon angioplasty, a larger lumen and vessel area and a smaller plaque area as determined by ICUS were associated with a larger angiographic MLD at follow-up. However, these relationships were weak, and the study did not identify ICUS parameters predictive of restenosis after PTCA.

References:

1. Circulation 1997;95:2254-61. Final results

Clinical Topics: Invasive Cardiovascular Angiography and Intervention, Noninvasive Imaging, Interventions and Coronary Artery Disease, Interventions and Imaging, Angiography, Nuclear Imaging

Keywords: Coronary Artery Disease, Follow-Up Studies, Coronary Angiography, Constriction, Pathologic, Angioplasty, Balloon, Coronary


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