Predictors of Rapid Plaque Progression: An Optical Coherence Tomography Study.

OBJECTIVES

This study sought to identify morphological predictors of rapid plaque progression.

BACKGROUND

Two patterns of plaque progression have been described: slow linear progression and rapid step-wise progression. The former pattern will cause stable angina when the narrowing reaches a critical threshold, whereas the latter pattern may lead to acute coronary syndromes or sudden cardiac death.

METHODS

Patients who underwent optical coherence tomography (OCT) imaging during the index procedure and follow-up angiography with a minimum interval of 6 months were selected. Nonculprit lesions with a diameter stenosis of ≥30% on index angiography were assessed. Lesion progression was defined as a decrease of angiographic minimum lumen diameter ≥0.4 mm at follow-up (mean, 7.1 months). Baseline morphological characteristics of plaques with rapid progression were evaluated by OCT. In a subgroup with follow-up OCT imaging for plaques with rapid progression, morphological changes from baseline to follow-up were assessed.

RESULTS

Among 517 lesions in 248 patients, 50 lesions showed rapid progression. These lesions had a significantly higher prevalence of lipid-rich plaque (76.0% vs. 50.5%, respectively), thin-cap fibroatheroma (TCFA) (20.0% vs. 5.8%, respectively), layered plaque (60.0% vs. 34.0%, respectively), macrophage accumulation (62.0% vs. 42.4%, respectively), microvessel (46.0% vs. 29.1%, respectively), plaque rupture (12.0% vs. 4.7%, respectively), and thrombus (6.0% vs. 1.1%, respectively) at baseline compared with those without rapid progression. Multivariate analysis identified lipid-rich plaque (odds ratio [OR]: 2.17; 95% confidence interval [CI]: 1.02 to 4.62; p = 0.045]), TCFA (OR: 5.85; 95% CI: 2.01 to 17.03; p = 0.001), and layered plaque (OR: 2.19; 95% CI: 1.03 to 4.17; p = 0.040) as predictors of subsequent rapid lesion progression. In a subgroup analysis for plaques with rapid progression, a new layer was detected in 25 of 41 plaques (61.0%) at follow-up.

CONCLUSIONS

Lipid-rich plaques, TCFA, and layered plaques were predictors of subsequent rapid plaque progression. A new layer, a signature of previous plaque disruption and healing, was detected in more than half of the lesions with rapid progression at follow-up. (Massachusetts General Hospital Optical Coherence Tomography Registry; NCT01110538).