Spotty calcium deposits within acute coronary syndrome (ACS)-causing culprit lesions impact inflammatory vessel-wall interactions and are associated with higher cardiovascular event rates at one year follow-up: Results from the prospective translational OPTICO-ACS study program

Background and aims: Spotty calcium deposits (SCD) represent a vulnerable plaque feature which seems to result -as based on recent in vitro studies -from inflammatory vessel-wall interactions. SCD can be reliably assessed by optical coherence tomography (OCT). Their prognostic impact is yet unknown. Therefore, the aims of this translational study were to comprehensively characterize different plaque calcification patterns, to analyze the associated inflammatory mechanisms in the microenvironment of acute coronary syndrome (ACS)-causing culprit lesions (CL) and to investigate the prognostic significance of SCD in a large cohort of ACS-patients.Methods: CL of the first 155 consecutive ACS-patients from the translational OPTICO-ACS-study program were investigated by OCT-characterization of the calcium phenotype at ACS-causing culprit lesions. Simultaneous immunophenotyping by flow-cytometric analysis and cytokine bead array technique across the CL gradient (ratio local/systemic levels) was performed and incidental major adverse cardiovascular events plus (MACE+) at 12 months after ACS were assessed.Results: SCD were observed within 45.2% of all analyzed ACS-causing culprit lesions (CL). Culprits containing spotty calcium were characterized by an increased culprit ratio of innate effector cytokines interleukin (IL)-8 [2.04 (1.24) vs. 1.37 (1.10) p < 0.05], as well as TNF (tumor necrosis factor)-alpha [1.17 (0.93) vs. 1.06 (0.89); p < 0.05)] and an increased ratio of circulating neutrophils [0.96 (0.85) vs. 0.91 (0.77); p < 0.05] as compared to culprit plaques without SCD. Total monocyte levels did not differ between the two groups (p = n.s.). However, SCD-containing CLs were characterized by an increased culprit ratio of intermediate monocytes [(1.15 (0.81) vs. 0.96 (0.84); p < 0.05)] with an enhanced surface expression of the integrin receptor CD49d as compared to intermediate monocytes derived from SCD-free CLs [(1.06 (0.94) vs. 0.97 (0.91)] p < 0.05. Finally, 12 months rates of MACE+ were higher in patients with, as compared to patients without SCD at CL (16.4% vs. 5.3%; p < 0.05).Conclusions: This study for the first time identified a specific inflammatory profile of CL with SCD, with a pre-dominance of neutrophils, intermediate monocytes and their corresponding effector molecules. Hence, this study advances our understanding of ACS-causing CL and provides the basis for future personalized anti-inflammatory, therapeutic approaches to ACS.