Implication of plaque color classification for assessing plaque vulnerability: a coronary angioscopy and optical coherence tomography investigation.

OBJECTIVES: The purpose of this study was to assess the relationship between plaque color evaluated by coronary angioscopy and fibrous cap thickness estimated by optical coherence tomography (OCT) in vivo. BACKGROUND: Yellow color intensity of coronary plaque evaluated by coronary angioscopy might be associated with plaque vulnerability. METHODS: Seventy-seven coronary artery plaques in patients with acute coronary syndrome were observed by angioscopy and OCT. Plaque color was graded as white, light yellow, yellow, or intensive yellow. RESULTS: There were significant differences among the groups classified by plaque color with respect to the fibrous cap thickness estimated by OCT: 389 +/- 74 mum in white plaques, 228 +/- 51 microm in light yellow plaques, 115 +/- 28 microm in yellow plaques, and 59 +/- 14 microm in intensive yellow plaques (p < 0.0001). In Spearman rank-order correlation analysis, there was a significant negative correlation between yellow color intensity and fibrous cap thickness (p < 0.0001). Furthermore, 80% of intensive yellow plaques were thin cap fibroatheroma with a cap thickness of < or =65 microm. CONCLUSIONS: The plaque color in coronary angioscopy was determined by the fibrous cap thickness, which was assessed by OCT. Although coronary angioscopy remains a specialized research tool, it might allow us to evaluate plaque vulnerability.

Comparison of vascular response after sirolimus-eluting stent implantation between patients with unstable and stable angina pectoris: a serial optical coherence tomography study.

OBJECTIVES: The aim of the present study was to compare lesion morphologies after sirolimus-eluting stent (SES) implantation between patients with unstable angina pectoris (UAP) and stable angina pectoris (SAP) with the use of optical coherence tomography (OCT). BACKGROUND: The lesion morphologies before and after coronary stenting have been proposed as important predictors of clinical outcome. The high resolution of OCT provides detailed information of coronary vessel wall. METHODS: We enrolled 55 patients (UAP: n = 24, SAP: n = 31), and examined lesion morphologies by using OCT at pre- and post-SES implantation and 9 months' follow-up. RESULTS: The incidence of plaque rupture (42% vs. 3%, p < 0.001), intracoronary thrombus (67% vs. 3%, p < or = 0.001) and thin-capped fibroatheroma (cap thickness <65 microm; 46% vs. 3%, p < 0.001) at pre-intervention was significantly greater in UAP than that in SAP. Although stent profiles and procedural characteristics were not different between the 2 groups, inadequate stent apposition (67% vs. 32%, p = 0.038) and tissue protrusion (79% vs. 42%, p = 0.005) after percutaneous coronary intervention were observed more frequently in patients with UAP. Plaque rupture was significantly increased after percutaneous coronary intervention in patients with UAP (42% to 75%, p = 0.018), and the persistence of core cavity after plaque rupture (28% vs. 4%, p = 0.031) at 9 months' follow-up was observed more frequently in UAP patients compared with SAP patients. At 9 months' follow-up, the incidence of inadequately apposed stent (33% vs. 4%, p = 0.012) and partially uncovered stent by neointima (72% vs. 37%, p = 0.019) was significantly greater in UAP patients than that in SAP patients. All patients took aspirin and ticlopidine during follow-up period, and no patients had stent thrombosis or adverse coronary events. CONCLUSIONS: Serial OCT examinations demonstrated markedly different vascular response up to 9 months after SES implantation between UAP and SAP patients. Although the inadequate lesion morphologies after stenting were observed more frequently in UAP patients, these findings were not associated with adverse outcomes in patients with antiplatelet therapy.

Assessment of culprit lesion morphology in acute myocardial infarction: ability of optical coherence tomography compared with intravascular ultrasound and coronary angioscopy.

OBJECTIVES: The aim of the present study was to evaluate the ability of optical coherence tomography (OCT) for assessment of the culprit lesion morphology in acute myocardial infarction (AMI) in comparison with intravascular ultrasound (IVUS) and coronary angioscopy (CAS). BACKGROUND: Optical coherence tomography is a new intravascular imaging method with a high resolution of approximately 10 microm. This may allow us to assess the vulnerable plaques in detail in vivo. METHODS: We enrolled 30 patients with AMI, and analyzed the culprit lesion by OCT, CAS, and IVUS. RESULTS: The average duration from the onset of symptom to OCT imaging was 3.8 +/- 1.0 h. The incidence of plaque rupture observed by OCT was 73%, and it was significantly higher than that by CAS (47%, p = 0.035) and IVUS (40%, p = 0.009). Furthermore, OCT (23%) was superior to CAS (3%, p = 0.022) and IVUS (0%, p = 0.005) in the detection of fibrous cap erosion. The intracoronary thrombus was observed in all cases by OCT and CAS, but it was identified in 33% by IVUS (vs. OCT, p < 0.001). Only OCT could estimate the fibrous cap thickness, and it was 49 +/- 21 microm. The incidence of thin cap fibroatheroma (TCFA) was 83% in this population by OCT. CONCLUSIONS: Optical coherence tomography is a feasible imaging modality in patients with AMI and allows us to identify not only plaque rupture, but also fibrous cap erosion, intracoronary thrombus, and TCFA in vivo more frequently compared with conventional imaging techniques.