Abstract 1715: Necrotic Core and its Ratio to Dense Calcium are Predictors of High-risk Non-ST-Elevation Acute Coronary Syndromes: Results from the Prospective, Multi-center, Global VH-IVUS Registry

Abstract

Background: Increased CK-MB levels and ST-segment depression are predictors of a worse prognosis in the setting of acute coronary syndromes (ACS). We hypothesized a relationship between virtual histology intravascular ultrasound (VH-IVUS) findings and these prognostic factors. Methods and Results: We performed whole vessel VH-IVUS measurements in a consecutive series of 225 pts presenting with non ST-elevation (NSTE) ACS on admission; the four basic VH-IVUS coronary plaque components - fibrous (FI), fibro-fatty (FF), dense calcium (DC) and necrotic core (NC) - were measured and the NC/DC ratio calculated. Pts age was 62 ± 11 years with 72% males and 23% diabetics. Among VH-IVUS parameters, only the NC/DC ratio had a positive association to CK-MB levels (r=0.21, p=0.03); it was also significantly higher for ST-depression vs. non-ST-depression ACS (1.97±0.37 vs. 1.58±0.31, p=0.02). A NC/DC value ≥2 was the threshold that best separated high-risk NSTE ACS pts from those with neither abnormal CK-MB nor abnormal ECG findings (odds ratio 3.8, p=0.01), and a %NC ≥6 best enhanced the predictive value of the NC/DC ratio (odds ratio 3.1, p=0.04). Pts with both NC/DC value ≥2 and %NC ≥6 had significantly higher LDL-C (132.46±49.80 vs. 100.28±36.46, p=0.001) and more myocardial injury when compared to pts with no predictors (p=0.002, Figure ). Conclusions: Using VH-IVUS analysis, we identified parameters that were positively associated to a high-risk ACS presentation. Our results in-vivo reinforce previous histopathological findings that both a larger necrotic core content and less quantitative calcium are substrates for plaque vulnerability.