Plaque characteristics and slow flow phenomenon during the percutaneous coronary intervention of superficial healed plaques on Optical Coherence Tomography

Abstract

Abstract Backgrounds Healed plaques in coronary artery are associated with plaque vulnerability 1,2). Superficial features in plaques such as a thin fibrous cap, infiltrated with macrophages and inflammatory cells, and spotty calcifications were associated with rupture-prone plaques 3). However, the plaque vulnerability according to the depth of the healed plaque is unclear. Objective We investigated the plaque characteristics on optical coherence tomography (OCT) and slow flow during percutaneous coronary intervention (PCI) for superficial healed plaques. Methods In total of 154 patients with 168 stable angina pectoris lesions underwent OCT before PCI. Healed plaques were defined as plaques with 1 or more layers with different optical densities and a clear demarcation from the underlying components. Superficial healed plaques were defined as healed plaques adjacent to the lumen. Deep healed plaques were defined as healed plaques not in contact with the lumen. Depth of deep healed plaque was 308 ± 114 µm. Results Compared to lesions without healed plaques, those with superficial healed plaques showed a significantly higher C-reactive protein levels (0.45 ± 1.07 vs. 0.19 ± 0.23, p = 0.039), a tendency toward a lower use of stain (37% [11/30] vs. 60% [62/103], p = 0.057), a significantly higher incidence of lipid-rich plaques (71% [22/31] vs. 41% [47/116], p = 0.002), thin-cap fibroatheromas (TCFAs) (48% [15/31] vs. 22% [26/116], p = 0.007), plaque rupture (45% [14/31] vs. 23% [27/116], p = 0.030), macrophage accumulation (71% [22/31] vs. 22% [26/116], p > 0.001), intraplaque neovessels (74% [23/31] vs. 33% [38/116], p < 0.001), and thrombus (29% [9/31] vs. 9% [11/116], p = 0.009), and a similar incidence of slow flow after stent implantation (16% [5/31] vs. 18% [21/116], p = 0.967). Compared to lesions with deep healed plaques, those with superficial healed plaques showed a tendency toward higher prevalence of diabetes mellitus (50% [15/30] vs. 19% [4/21], p = 0.071), a significantly higher incidence of multivessel disease (73% [22/30] vs. 29% [6/21], p = 0.002), calcification on angiography (35% [11/31] vs. 0% [0/21], p = 0.016), a significantly higher incidence of lipid-rich plaques (71% [22/31] vs. 33% [7/21], p = 0.009), TCFAs (48% [15/31] vs. 5% [1/21], p = 0.001), plaque rupture (45% [14/31] vs. 5% [1/21], p = 0.003), macrophage accumulation (71% [22/31] vs. 24% [5/21], p = 0.001), intraplaque neovessels (74% [23/31] vs. 29% [6/21], p = 0.002), and thrombus (29% [9/31] vs. 5% [1/21], p = 0.024). For OCT findings, the multivariable analysis showed that macrophage accumulation was an independent predictor of superficial healed plaques (odds ratio 5.55, 95% CI 2.03-15.17, p = 0.001). Conclusions Lesions with superficial healed plaques were associated with high plaque vulnerability on OCT, systemic inflammation, less use of statins, diabetes mellitus, and multivessel disease and were not associated with slow flow during PCI.OCT images of superficial healed plaquesTable.OCT findings