Abstract 17883: Association Between Lp-PLA&rtf-inf-start;2 &rtf-inf-end;Activity and Fibrous Cap Thickness and Plaque Volume in Patients with ACS: An Optical Coherence Tomography and Intravascular Ultrasound Study

Abstract

Backgrounds: Lipoprotein-associated phospholipase A₂ level (Lp-PLA₂) is positively correlated with an increased risk of developing acute coronary syndrome (ACS). However, information on the relationship between Lp-PLA₂ activity and fibrous-cap thickness (FCT), a key determinant of plaque vulnerability, is scarce.

Aim: This study aimed to evaluate the in-vivo association between changes in Lp-PLA2 activity, and FCT identified by optical coherence tomography (OCT) and plaque volume measured by intravascular ultrasound (IVUS).

Methods: We enrolled 24 consecutive patients with ACS. OCT and IVUS were performed in non-target lesions at two time points: during the index procedure and after 12 months. The FCT was determined by OCT and plaque volume was measured by IVUS.

Results: Lp-PLA₂ activity decreased significantly from baseline to 12 months (48.5±16.3 vs. 34.9±13.8 nmol/min/mL, p <0.001). FCT increased significantly from baseline to follow-up (63.5±14.1 vs. 109.9±38.8 µm, p<0.001). The 12-month IVUS images did not show significant changes in plaque volume (84.1±61.6 mm³ vs. 87.5±60.4 mm³, p=0.23). Significant correlation was observed between changes in FCT and changes in Lp-PLA₂ activity (r = -0.56, p=0.006, Figure 1A). Changes in plaque volume correlated significantly with changes in Lp-PLA₂ activity between baseline and 12 months (r = 0.52, p=0.01, Figure 1B).

Conclusions: A significant association was observed between serial changes in Lp-PLA₂ activity, and changes in FCT and plaque volume in patients with ACS. Inhibition of Lp-PLA₂ activity in patients with ACS may be a promising approach to stabilize plaques and even reverse atherosclerosis.