Abstract 4912: Thin Fibrous Caps with Excessive Macrophage Infiltration in Culprit Lesions of Patients with Acute Coronary Syndromes are Associated with Increased Local Temperature

Abstract

Background: Optical coherence tomography (OCT) provides detailed analysis of the morphological characteristics of the culprit lesion (CL) and determines macrophage density within fibrous caps. Intracoronary thermography (ICT) detects the local inflammatory activation of the CL. We investigated the correlation between morphological and functional characteristics of the CL as analysed by OCT and ICT in patients with acute coronary syndromes (ACS). Methods: We studied 31 CL of 31 pts (mean age 61±14 years) with ACS. We measured by ICT the temperature difference between the lesion and the healthy proximal vessel wall (ΔT). Thereafter, we measured the minimal thickness of the fibrous cap (mTFC) at CL by OCT. CL with mTFC ≤65 μm were characterized as thin cap plaques and CL with mTFC >65 μm as thick cap plaques. By OCT, macrophage density in the fibrous cap of the CL was also determined from optical signals. Results: Nineteen CL (61.29%) had increased plaque temperature (ΔT≥0.05°C) and 12 CP (38.7%) had low ΔT (ΔT<0.05°C). All CL (100%, p<0.01) with low ΔT had thick cap (mTFC=98±22 μm). Three CL (15.78%) with high ΔT had thick cap (mTFC=78±9μm, p=0.02), whereas 16 CL with high ΔT (84.2%) had thin cap plaques (mTFC=49±12μm, p=0.02) (Figure ). Among CL with high ΔT, 18 CL (94.7%) had excessive macrophage infiltration in OCT analysis. Only 1 CL with low ΔT(8.3%) had macrophage infiltration of its fibrous cap (p<0.01). Conclusions: CL with thin fibrous cap have increased inflammatory activation. Morphological and functional characteristics of the CL of pts with ACS, evaluated by OCT and ICT, are correlated. Thus, the use of OCT and ICT can provide more information regarding the high-risk plaques.