Abstract 9935: Culprit Plaque Morphology in Young versus Elder Acute Coronary Syndrome Patients: An Optical Coherence Tomography Study

Abstract

Objective: Culprit plaque morphology in young acute coronary syndrome (ACS) patients differs from that of elder patients. The underlying mechanisms responsible for ACS in younger compared to elder patients are yet to be explored with optical coherence tomography. Methods: This was a prospective, single-center, investigational study. Patients were divided into groups according to age, ≤35 (N=43) and >35 years (N=50) and further subdivided according to the underlying mechanism i.e. plaque rupture (PR) and plaque erosion (PE). Results: A total of 93 patients were included in this analysis. Thin-cap fibroatheroma (TCFA) was significantly higher among elder than younger patients for both PR (80.0% vs. 31.8%, p=0.002) and PE (66.7% vs. 6.3%, p<0.001) groups. Microchannels were also significantly more prevalent among elder than younger patients for both PR (65.0% vs. 18.2%, p=0.004) and PE groups (55.6% vs.12.5%, p=0.013). Macrophages were significantly higher in elder than younger patients for both PR (25.0% vs. 0%, p=0.018) and PE (44.4% vs. 0%, p=0.003) groups. In contrast, fibrous cap thickness was greater in younger than elder patients for both PR (105.71±48.02 μm vs. 58.00±15.76 μm, p<0.001) and PE (126.67±48.22 μm vs. 54.38±24.21 μm, p<0.001) groups. Intimal thickness was greater in elder than younger patients for both PR (728.00±313.92 mm 2 vs. 342.27±142.02 mm 2 , p<0.001) and PE (672.78±334.57 mm 2 vs. 295.00±99.60 mm 2 , p<0.001) groups. Plaque type, thrombus formation, and minimal luminal diameter did not differ significantly according to age. Conclusion: We conclude that the high resolution of OCT is able to define the detailed microstructure of the culprit lesion and allows a greater understanding of the mechanisms of coronary artery disease. The frequency of TCFA, microchannels, macrophages, and intimal thickness was significantly higher in elder ACS patients compared to younger patients. However, fibrous cap thickness was significantly greater in younger ACS patients compared to elder patients.