Morphological Characteristics of Eroded Plaques with Noncritical Coronary Stenosis: An Optical Coherence Tomography Study

Aims: Recent studies suggested plaque erosion with noncritical stenosis could be treated distinctly from that with critical stenosis, but their morphological features remained largely unknown. The present study aimed to investigate morphological features of eroded plaques with different lumen stenosis using optical coherence tomography (OCT). Methods: A total of 348 ST-segment elevated myocardial infarction patients with culprit OCT-defined plaque erosion (OCT-erosion) were analyzed. Based on the severity of lumen area stenosis, all patients with OCT-erosions were divided into the following three groups: Group A (area stenosis < 50%, n= 50); Group B (50% <= area stenosis <75%, n= 146); Group C (area stenosis >= 75%, n= 152). Results: Compared with patients in Groups A and B, patients in Group C were older (p= 0.008) and had higher prevalence of hypertension (p= 0.029). Angiographic analysis showed that 72.0% of the eroded plaques in Group A were located in the left anterior descending artery, followed by 67.8% in Group B, and 53.9% in Group C (p= 0.039). OCT analysis showed that Group A had the highest prevalence of fibrous plaques (p<0.001) and nearby bifurcation (p= 0.036), but the lowest prevalence of lipid-rich plaques (p< 0.001), macrophage accumulation (p< 0.001), microvessels (p= 0.009), cholesterol crystals (p< 0.001), and calcification (p= 0.023). Multivariable regression analysis showed fibrous plaque (odds ratio [OR]: 3.014, 95% confidence interval [CI]: 1.932-4.702, p<0.001) and nearby bifurcation (OR: 1.750, 95% CI: 1.109-2.761, p= 0.016) were independently associated with OCT-erosion with an area stenosis of < 75%. Conclusions: More than half of OCT-erosions presented with < 75% area stenosis, having distinct morphological features from those of OCT-erosions with critical stenosis. Fibrous plaque and nearby bifurcation were independently associated with noncritically stenotic OCT-erosion, suggesting that eroded plaques might need individualized treatment.