Abstract 578: Spotty Calcification as a Marker of Vulnerable Plaque: Novel Findings From in vivo Study in Survivors of Cardiac Arrest and in vitro Study in Autopsied Patients of Sudden Cardiac Death

Abstract

Backgrounds: We previously reported that spotty calcification detected by intravascular ultrasound (IVUS) was often associated with histological fibroatheromas (JACC, 2014, 63:2220-2233). However, the exact mechanisms underlying spotty calcification and the associated risk for ischemic events remain poorly understood. In the present study, we performed a multimodality imaging study on spotty calcification using IVUS, near-infrared spectroscopy (NIRS) and optical coherent tomography (OCT) in survivors of cardiac arrest and autopsied patients of sudden cardiac death (SCD). Methods and Results: IVUS, NIRS and OCT were performed in 62 vessels from patients who had a documented sudden cardiac arrest but successfully resuscitated and 52 vessels from autopsied patients of SCD. Spotty calcification was detected in 88.5% survivors of cardiac arrest; 78.3% of them had spotty calcium in superficial location. About 83.3% superficial spotty calcium co-existed with echo-attenuated plaques on IVUS, 73.9% co-existed with thin-cap fibroatheroma (TCFA) or plaque rupture on OCT, and 88.8% of contained lipid core plaque on NIRS (Figure 1). The arc of spotty calcium was negatively correlated with lipid core burden index on NIRS (Spearman ρ=-0.40, P =0.03), and positively correlated with cap thickness on OCT (Spearman ρ=0.41, P =0.01). In in vitro study, IVUS and OCT detected spotty calcification in 80.6% SCD patients. On pathological analyses, the arc of spotty calcium was negatively correlated with 1) inflammation of fibrous cap, 2) levels of oxidative/nitrative stress, and 3) apoptosis and necrotic core size. Compared with spotty calcium in deep location, that in superficial location was associated with larger size of necrotic core ( P =0.02) and more TCFA ( P <0.001) and plaque rupture ( P =0.006). Conclusions: Spotty calcification, especially when superficial in location, is a marker of vulnerable plaque in survivors of cardiac arrest and autopsied patients of SCD.