P5623Plaque characteristics, slow flow during percutaneous coronary intervention, and clinical outcomes of irregular protrusion by optical coherence tomography

Introduction In pathological studies, penetration of the lipid core into the stent strut is associated with neointimal growth and stent thrombosis. Irregular protrusion on optical coherence tomography (OCT) is associated with clinical events and target lesion revascularization. However, there are few reports about the relationship among irregular protrusion, plaque characteristics, and slow flow during percutaneous coronary intervention. We investigated clinical and procedure characteristics, plaque characteristics, slow flow after stent implantation, and clinical outcomes with irregular protrusion by using OCT. Methods Eighty-four lesions in 76 patients undergoing OCT before percutaneous coronary intervention were evaluated. Irregular protrusion was defined as protrusion of material with an irregular surface into the lumen between stent struts with a maximum height of ≥100 μm. Major adverse clinical outcomes were defined as death, acute myocardial infarction, acute coronary syndrome, or target lesion revascularization. Results Lesions with irregular protrusion were found in 56% (47/84). Compared with lesions without irregular protrusion, those with irregular protrusion had significantly higher low-density lipoprotein cholesterol (LDL-C) levels (108±31 mg/dL vs. 95±25 mg/dL, P=0.044); a tendency toward decreased use of statins (44% [19/43] vs. 67% [22/33], P=0.065); significantly larger reference vessel diameter (3.12±0.53 mm vs. 2.74±0.63 mm, P=0.004); significantly larger stent diameter (3.23±0.43 mm vs. 3.00±0.49 mm, P=0.025); a tendency toward longer total stent length (29.3±14.2 mm vs. 23.7±11.4 mm, P=0.056); significantly larger maximum balloon diameter (3.56±0.55 mm vs. 3.22±0.63 mm, P=0.010); significantly higher incidence of slow flow after stent implantation (38% [18/47] vs. 11% [4/37], P=0.006); significantly higher ΔTIMI flow from pre-stenting to post-stenting (0.4±0.6 vs. 0.1±0.3, P=0.009); significantly higher incidence of lipid-rich plaque (70% [33/47] vs. 35% [13/37], P=0.002); thin-cap fibroatheromas (TCFAs: 49% [23/47] vs. 5% [2/37], P<0.001); plaque rupture (40% [19/47] vs. 16% [6/37], P=0.018); macrophage accumulation (51% [24/47] vs. 24% [9/37], P=0.015); internal running vasa vasorum (51% [24/47] vs. 11% [4/37], P<0.001); thrombus (32% [15/47] vs. 3% [1/37], P<0.001); and a tendency higher incidence of one-year adverse clinical outcomes (12% [5/43] vs. 0% [0/33], P=0.075: log rank). The multivariable analysis showed that TCFA was an independent predictor of irregular protrusion (odds ratio 9.00, 95% CI 1.32–61.36, P=0.025). Conclusions Irregular protrusion on OCT was associated with high plaque vulnerability, higher LDL-C, less frequent use of statin, larger vessel diameter, longer total stent length, slow flow after stent implantation, and one-year adverse clinical outcomes.