SAN FRANCISCO - New clinical trial results show that the presence of vulnerable plaque on VH intravascular ultrasound (IVUS) imaging before percutaneous coronary intervention (PCI) is significantly associated with poorer three-year outcomes.
Conversely, the absence of at least a 10% necrotic core at baseline on VH IVUS (Volcano Therapeutics, San Diego, CA) imaging was a strong predictor of lesion stability, according to lead investigator Dr. Gregg Stone from Columbia University Medical Center In New York City.
"Looking at the angiographic severity of the blockage is not enough … we must understand the type of disease present in the vessel wall," Stone said.
The PROSPECT (Providing Regional Observations to Study Predictors of Events in the Coronary Tree) trial examined 700 patients at 40 clinical centers in the U.S. and Europe. Following VH IVUS imaging of the target vessels, all patients received PCI for acute coronary syndromes (ACS) including unstable angina, ST-segment elevation myocardial infarction (STEMI), or non-T-segment elevation myocardial infarction (NSTEMI).
The hazard ratio for a thin-cap fibroatheroma (TCFA) identified at VH IVUS was 3.8 (p < 0.0001), indicating a statistically significant predictor of an event, versus a hazard ratio of 0.2 for pathological intimal thickening (PIT) lesions, which were significantly less likely to cause an event.
The absence of a TCFA (< 10% necrotic core at VH IVUS) was a strong predictor of lesion stability over a three-year follow-up period. The likelihood of the lesion progressing to an event over three years was negligible, independent of other grayscale and angiographic factors, the researchers reported.
The plaque type yielding the highest risks were fibroatheromas with a minimum lumen area of ≤ 4 mm2 and a plaque burden ≥ 70%. Three independent predictors combined showed that such a lesion imaged at baseline had a 17.2% chance of causing an adverse cardiac event within three years.
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| Lesions consisting of >10% thin-cap fibrous atheroma were far likelier to cause adverse events within three years of percutaneous coronary intervention. Image courtesy of Volcano Therapeutics. |
The study demonstrates that lesions characterized as mild on angiography are capable of progressing quickly to cause events, and that the sites of adverse events are often missed at angiography, according to Volcano. Current practice using angiography guidance alone is insufficient in that regard, the company added.
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