Masato Mizukoshi

Effect of statin therapy on coronary fibrous-cap thickness in patients with acute coronary syndrome: assessment by optical coherence tomography study.

BACKGROUND The thickness of coronary fibrous caps is a major determinant of vulnerable plaques. Several clinical trials have suggested that statin therapy could stabilize vulnerable plaques. Recently, optical coherence tomography (OCT) has been proposed as an effective histology-resolution imaging modality for assessing such micro-structural changes. METHODS Forty AMI patients with hyperlipidemia were enrolled and underwent percutaneous coronary intervention (PCI). They were divided into two groups; statin treatment group (n=23) or control group (n=17). Serial OCT analyses were performed at baseline and 9-month follow-up for a non-PCI lipid-rich plaque lesion. RESULTS The LDL-cholesterol level in the statin group was significantly lower than that in the control group at follow-up. Although the fibrous-cap thickness was significantly increased in both the statin treatment group (151+/-110 to 280+/-120 microm, p<0.01) and the control group (153+/-116 to 179+/-124 microm, p<0.01) during follow-up period, the degree of increase was significantly greater in the statin treatment group than in the control group (188+/-64% vs. 117+/-39%, p<0.01). Furthermore, when the patients in the statin treatment group were divided into two subgroups (fibrous-cap thickness or=median), the thin fibrous-cap group (or=median). CONCLUSION The lipid-lowering therapy with statin for 9 months after the onset of acute myocardial infarction significantly increased the fibrous-cap thickness in patients with hyperlipidemia.

Morphology of Exertion-Triggered Plaque Rupture in Patients With Acute Coronary Syndrome An Optical Coherence Tomography Study

Background— Plaque rupture and secondary thrombus formation play key roles in the onset of acute coronary syndrome (ACS). One pathological study suggested that the morphologies of plaque rupture differed between rest-onset and exertion-triggered rupture in men who experienced sudden death. The aim of the present study was to use optical coherence tomography to investigate the relationship in patients with ACS between the morphology of a ruptured plaque and the patients activity at the onset of ACS. Methods and Results— The study population was drawn from 43 consecutive ACS patients (with or without ST-segment elevation) who underwent optical coherence tomography and presented with a ruptured plaque at the culprit site. Patients were divided into a rest group and an exertion group on the basis of their activities at the onset of ACS. The thickness of the broken fibrous cap correlated positively with activity at the onset of ACS. The culprit plaque ruptured at the shoulder more frequently in the exertion group than in the rest group (rest 57% versus exertion 93%, P=0.014). The thickness of the broken fibrous cap in the exertion group was significantly higher than in the rest-onset group (rest onset: 50 &mgr;m [interquartile median 15 &mgr;m]; exertion: 90 &mgr;m [interquartile median 65 &mgr;m], P<0.01). Conclusions— The morphologies of exertion-triggered and rest-onset ruptured plaques differ in ACS patients. Our data suggest that a thin-cap fibroatheroma is a lesion predisposed to rupture both at rest and during the patients day-to day activity, and some plaque rupture may occur in thick fibrous caps depending on exertion levels.

Advantage of next-generation frequency-domain optical coherence tomography compared with conventional time-domain system in the assessment of coronary lesion.

Background: Intracoronary optical coherence tomography (OCT) is a high‐resolution imaging modality used for evaluation of coronary lesion morphology. However, current time‐domain OCT (TD‐OCT) have a number of limitations with regard to both procedural usage and safety in the clinical setting. The next‐generation frequency‐domain OCT (FD‐OCT), which has a much faster frame rate and pullback speed than TD‐OCT, is expected to overcome these limitations. The aim of this study was to evaluate the feasibility and usability of next generation FD‐OCT in the assessment of coronary lesions. Methods: A comparison study was performed between FD‐OCT and TD‐OCT from the aspect of usability (set‐up time), qualitatively (rate of clear image segment), and safety (adverse event) in 14 ischemic heart disease patients with 20 previously implanted coronary stents. Results: The mean time of the OCT procedure in this study from setup to completion of image acquisition was 3.2 ± 0.8 min for FD‐OCT and 11.2 ± 2.5 min for TD‐OCT (P < 0.01). In qualitative image assessment, FD‐OCT has the potential to yield a higher rate of clear image segments (CIS) than TD‐OCT (99.4% vs. 80.8%, respectively; P < 0.01). In addition to these improved characteristics, there were no ischemic ECG changes or arrhythmia associated with FD‐OCT. Conclusions: The next‐generation intracoronary FD‐OCT has better performance in the clinical setting and the potential to overcome several limitations of conventional TD‐OCT systems.

Difference of Culprit Lesion Morphologies Between ST-Segment Elevation Myocardial Infarction and Non–ST-Segment Elevation Acute Coronary Syndrome : An Optical Coherence Tomography Study

OBJECTIVES The aim of this study was to investigate the difference of culprit lesion morphologies assessed by optical coherence tomography (OCT) between ST-segment elevation myocardial infarction (STEMI) and non-ST-segment elevation acute coronary syndrome (NSTEACS). BACKGROUND Autopsy studies have reported that rupture of a thin-cap fibroatheroma and subsequent thrombus formation is the most important mechanism leading to acute coronary syndrome (ACS). Optical coherence tomography is a high-resolution imaging modality that is capable of investigating detailed coronary plaque morphology in vivo. METHODS We examined the culprit lesion morphologies by OCT in 89 consecutive patients with acute coronary syndrome (STEMI = 40; NSTEACS = 49). RESULTS The incidence of plaque rupture, thin-cap fibroatheroma, and red thrombus was significantly higher in STEMI compared with NSTEACS (70% vs. 47%, p = 0.033, 78% vs. 49%, p = 0.008, and 78% vs. 27%, p < 0.001, respectively). Although the lumen area at the site of plaque rupture was similar in the both groups (2.44 ± 1.34 mm(2) vs. 2.96 ± 1.91 mm(2), p = 0.250), the area of ruptured cavity was significantly larger in STEMI compared with NSTEACS (2.52 ± 1.36 mm(2) vs. 1.67 ± 1.37 mm(2), p = 0.034). Furthermore, the ruptured plaque of which aperture was open-wide against the direction of coronary flow was more often seen in STEMI compared with NSTEACS (46% vs. 17%, p = 0.036). CONCLUSIONS The present OCT study demonstrated the differences of the culprit lesion morphologies between STEMI and NSTEACS. The morphological feature of plaque rupture and the intracoronary thrombus could relate to the clinical presentation in patients with acute coronary disease.

Lipid-rich plaque and myocardial perfusion after successful stenting in patients with non-ST-segment elevation acute coronary syndrome: an optical coherence tomography study

AIMS Although some recent guidelines recommend an early invasive strategy for non-ST-segment elevation acute coronary syndrome (NSTEACS), several studies have failed to identify any benefit for very early intervention for NSTEACS. The no-reflow phenomenon may inhibit the expected benefit from very early recanalization for NSTEACS subjects. The aim of this study was to investigate whether optical coherence tomography (OCT) could predict no-reflow in patients with NSTEACS. METHODS AND RESULTS This study comprised 83 consecutive patients with NSTEACS who underwent OCT and successful emergent primary stenting. On the basis of post-stent TIMI flow, patients were divided into two groups: no-reflow group (n = 14) and reflow group (n = 69). Thin-cap fibroatheroma (TCFA) was defined as a plaque presenting lipid content for >90 degrees , and with thinnest part of the fibrous cap measuring <70 microm. Thin-cap fibroatheroma were more frequently observed in the no-reflow group than in the reflow group (50% vs. 16%, P = 0.005). The frequency of the no-reflow phenomenon increases according to the size of the lipid arc in the culprit plaque. Final TIMI blush grade also deteriorated according to the increase in the lipid arc. A multivariable logistic regression model revealed that lipid arc alone was an independent predictor of no-reflow (odds ratio 1.018; CI 1.004-1.033; P = 0.01). CONCLUSION Optical coherence tomography can predict no-reflow after percutaneous coronary intervention (PCI) in NSTEACS. The lipid contents of a culprit plaque may play a key role in damage to the microcirculation after PCI for NSTEACS. From our results, it is found that OCT is useful tool for stratifying risk for PCI for NSTEACS.

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.

Multiple Coronary Lesion Instability in Patients With Acute Myocardial Infarction as Determined by Optical Coherence Tomography

Autopsy studies have suggested that acute myocardial infarction (AMI) represents a pan-coronary process of vulnerable plaque development. We performed multifocal optical coherence tomographic (OCT) examination to compare coronary lesion instability between AMI and stable angina pectoris (SAP). A total of 42 patients with AMI (n = 26) or SAP (n = 16) who had multivessel disease and underwent multivessel coronary intervention were enrolled in the present study. The OCT examination was performed not only in the infarct-related/target lesions, but also in the noninfarct-related/nontarget lesions. OCT-derived thin-cap fibroatheroma (TCFA) was defined as a lesion with a fibrous cap thickness of <65 microm. In the infarct-related/target lesions, plaque rupture (77% vs 7%, p <0.001) and intracoronary thrombus (100% vs 0%, p <0.001) were observed more frequently in AMI than in SAP. The fibrous cap thickness (57 + or - 12 vs 180 + or - 65 microm, p <0.001) was significantly thinner in AMI and the frequency of OCT-derived TCFA (85% vs 13%, p <0.001) was significantly greater in AMI than in SAP. In the noninfarct-related/nontarget lesions, the frequency of plaque rupture was not different between the 2 groups. Intracoronary thrombus was observed in 8% of AMI, but it was not found in SAP. The fibrous cap thickness (111 + or - 65 vs 181 + or - 70 microm, p = 0.002) was significantly thinner in AMI and the frequency of OCT-derived TCFA (38% vs 6%, p = 0.030) was significantly greater in AMI than in SAP. Multiple OCT-derived TCFAs in both the infarct-related/target and the noninfarct-related/nontarget lesions were observed in 38% of patients with AMI but not in patients with SAP (p = 0.007). In conclusion, the present OCT examination demonstrated multiple lesion instability in the presence of AMI.

Distribution and frequency of thin-capped fibroatheromas and ruptured plaques in the entire culprit coronary artery in patients with acute coronary syndrome as determined by optical coherence tomography.

The aim of this study was to investigate the distribution and frequency of thin-capped fibroatheromas (TCFAs) within the entire length of culprit coronary arteries in patients with acute coronary syndrome. Our population was drawn from 43 consecutive patients with acute coronary syndrome (with or without ST-segment elevation) who underwent optical coherence tomography to visualize the entire culprit coronary artery using a nonocclusive optical coherence tomographic technique. Patients were categorized divided into a TCFA group or a no-TCFA group on the basis of the optical coherence tomographic findings. There were no differences in baseline characteristics or angiographic findings between the 2 groups. High-sensitive C-reactive protein in the TCFA group was significantly higher than in the no-TCFA group (median 3.3 mg/L, interquartile 3.1, vs 1.7 mg/L, interquartile 2.2, p = 0.03). Plaque rupture was found in 28 patients (65%) and multiple plaque ruptures in 5 patients (12%). Optical coherence tomogram revealed 21 TCFAs in 18 patients (42%). Multiple TCFAs were found in the same vessel in 3 patients (7%). The distribution of TCFAs in the right coronary arteries of our subject population was relatively even (proximal 2 [12%], mid 5 [29%], distal 3 [18%], p = 0.42), whereas TCFAs in the left anterior descending artery were common in proximal sites (proximal 6 [27%], mid 2 [9%], distal 0, p = 0.018). In conclusion, the use of optical coherence tomography to look for TCFAs and identify their distribution when combined with C-reactive protein may contribute to forming a strategy for preventing impending coronary events.

The effect of lipid and inflammatory profiles on the morphological changes of lipid-rich plaques in patients with non-ST-segment elevated acute coronary syndrome: follow-up study by optical coherence tomography and intravascular ultrasound.

OBJECTIVES The aim of this study was to determine the relationship between the morphological changes of nonculprit lipid-rich plaques and several clinical profiles in patients with non-ST-segment elevated acute coronary syndrome (NSTEACS). BACKGROUND Identification of coronary lesion with morphological characteristics of rupture-prone plaques is still difficult. METHODS Eighty-two consecutive patients with NSTEACS who underwent percutaneous coronary intervention were enrolled. The changes in total atheroma volume (TAV) of residual nonculprit lipid-rich plaques and the changes in the corresponding fibrous cap thickness (FCT) were assessed by intravascular ultrasound and optical coherence tomography, respectively, at baseline and after 9 months. RESULTS The percentage changes in TAV (mm(3)) of lipid-rich plaques and in the corresponding FCT (microm) over the 9-month follow-up period were 3.1 +/- 11% and 15 +/- 17%, respectively. There was no significant correlation between the changes in TAV and those in FCT. The change in TAV showed a significant correlation with reduction of the low-density lipoprotein/high-density lipoprotein (LDL/HDL) ratio (r = 0.42, p < 0.01). In contrast, the change in FCT showed no correlation with LDL/HDL ratio but had a significant positive correlation with changes in high-sensitivity C-reactive protein (r = 0.44, p < 0.01). Furthermore, in multivariate logistic analysis, statin use was an independent predictor of changes in well-stabilized plaques that showed both TAV reduction and FCT increase. CONCLUSIONS The changes in TAV and FCT of coronary plaques over a 9-month observation period were related to 2 different independent factors (i.e., reduction of LDL-cholesterol and high-sensitivity C-reactive protein, respectively). Furthermore, lipid-lowering therapy with statin has the potential to stabilize these parameters by both plaque reduction and FCT.

Conformational change in coronary artery structure assessed by optical coherence tomography in patients with vasospastic angina.

OBJECTIVES The aim of this study was to investigate the conformational change of arterial structure in the vasospastic lesion with optical coherence tomography. BACKGROUND Coronary artery spasm plays an important role in the pathogenesis of ischemic heart diseases. The conformational change of each arterial layer during vasospasm has not been studied in detail. METHODS We assessed 19 coronary arteries (10 spasm and 9 nonspasm lesions) with optical coherence tomography during the provocation test for coronary spasm. An intimal bump was defined as 1 or more intimal projections into the lumen that disappeared after the administration of nitroglycerine (NTG). Intimal gathering was defined as a folding/gathering of the intima, resulting in multiple kinks in the luminal contour that resolved after the administration of NTG. RESULTS The spasm lesion more frequently showed an intimal bump at baseline and intimal gathering during spasm compared with the nonspasm lesion (spasm 80% vs. nonspasm 0%, p < 0.01, spasm 100% vs. nonspasm 0%, p < 0.01, respectively). The spasm lesion demonstrated a thicker maximum media thickness (spasm 0.24 ± 0.04 mm vs. nonspasm 0.12 ± 0.03 mm, p < 0.01) at baseline, whereas no differences were observed after the administration of NTG (spasm 0.13 ± 0.03 mm vs. nonspasm 0.13 ± 0.02 mm, p = 0.65). CONCLUSIONS Our results suggest that medial contraction occurs even in an asymptomatic state and facilitates the formation of an intimal bump in patients with vasospastic angina. Luminal narrowing during spasm is associated with intimal gathering without alteration of intimal area.