Hideki Kawai

Impact of Statin Therapy on Plaque Characteristics as Assessed by Serial OCT, Grayscale and Integrated Backscatter–IVUS

OBJECTIVES The purpose of this study was to evaluate the effect of statin treatment on coronary plaque composition and morphology by optical coherence tomography (OCT), grayscale and integrated backscatter (IB) intravascular ultrasound (IVUS) imaging. BACKGROUND Although previous studies have demonstrated that statins substantially improve cardiac mortality, their precise effect on the lipid content and fibrous cap thickness of atherosclerotic coronary lesions is less clear. While IVUS lacks the spatial resolution to accurately assess fibrous cap thickness, OCT lacks the penetration of IVUS. We used a combination of OCT, grayscale and IB-IVUS to comprehensively assess the impact of pitavastatin on plaque characteristics. METHODS Prospective serial OCT, grayscale and IB-IVUS of nontarget lesions was performed in 42 stable angina patients undergoing elective coronary intervention. Of these, 26 received 4 mg pitavastatin after the baseline study; 16 subjects who refused statin treatment were followed with dietary modification alone. Follow-up imaging was performed after a median interval of 9 months. RESULTS Grayscale IVUS revealed that in the statin-treated patients, percent plaque volume index was significantly reduced over time (48.5 ± 10.4%, 42.0 ± 11.1%; p = 0.033), whereas no change was observed in the diet-only patients (48.7 ± 10.4%, 50.4 ± 11.8%; p = NS). IB-IVUS identified significant reductions in the percentage lipid volume index over time (34.9 ± 12.2%, 28.2 ± 7.5%; p = 0.020); no change was observed in the diet-treated group (31.0 ± 10.7%, 33.8 ± 12.4%; p = NS). While OCT demonstrated a significant increase in fibrous cap thickness (140 ± 42 μm, 189 ± 46 μm; p = 0.001), such changes were not observed in the diet-only group (140 ± 35 μm, 142 ± 36 μm; p = NS). Differences in the changes in the percentage lipid volume index (-6.8 ± 8.0% vs. 2.8 ± 9.9%, p = 0.031) and fibrous cap thickness (52 ± 32 μm vs. 2 ± 22 μm, p < 0.001) over time between the pitavastatin and diet groups were highly significant. CONCLUSIONS Statin treatment induces favorable plaque morphologic changes with an increase in fibrous cap thickness, and decreases in both percentage plaque and lipid volume indexes.

Coronary CT angiographic characteristics of culprit lesions in acute coronary syndromes not related to plaque rupture as defined by optical coherence tomography and angioscopy.

AIMS Pathological and clinical optical coherence tomography (OCT) studies have indicated that acute coronary syndrome (ACS) lesions have either ruptured fibrous caps (RFC-ACS) or intact fibrous caps (IFC-ACS). Although computed tomographic (CT) angiographic characteristics of RFC-ACS include low-attenuation plaques and positive plaque remodelling, features associated with IFC-ACS have not been previously described. The aim of this study was to assess the CT characteristics of IFC-ACS lesions. METHODS AND RESULTS Seventy-four patients with ACS/stable angina consented to multimodality imaging, of which 66 underwent CT angiography. Of these, 57 culprit lesions in 57 patients were evaluated with sufficient image quality from all four of OCT, angioscopy, intravascular ultrasound, and CT angiography. Intraluminal thrombus was assessed by OCT/angioscopy, and culprit lesions further classified by OCT-based demonstration of fibrous cap integrity. Of 35 culprit lesions with ACS, OCT revealed IFC with thrombus in 10 (29%) and RFC in the remaining 25 (71%); all 22 lesions with stable angina had intact fibrous caps. Fibrous caps were significantly thinner in RFC-ACS than IFC-ACS and stable angina (45 ± 12, 131 ± 57, and 321 ± 146 μm, respectively; P = 0.001). CT angiography revealed that low-attenuation plaques were more frequently observed in RFC-ACS than IFC-ACS and stable angina (88, 40, and 18%; P = 0.001) lesions. Similarly, positive remodelling was more predominantly seen in RFC-ACS than IFC-ACS and stable angina (96, 20, and 14%; P = 0.001). However, none of the specific CT angiography features clearly distinguished IFC-ACS from stable lesions. CONCLUSION In contrast to the situation with RFC-ACS, distinct culprit lesion characteristics associated with non-rupture-related mechanisms are not identified by CT angiography. It will therefore not be possible to differentiate plaques likely to develop IFC-ACS from stable plaques.

Characteristics of plaque progression detected by serial coronary computed tomography angiography

We previously reported that serial coronary computed tomography angiography (CTA) had a potential to evaluate the interval change of plaque morphology of coronary arteries. The aim of this study was to evaluate variables associated with the plaque progression by serial CTA. We included 148 patients (age 66.3 ± 9.8 years, male 81.1 %, median scan interval 12 months) with coronary artery disease undergoing serial CTA. Each coronary artery was compared visually between baseline and follow-up CTA to detect plaque progression. Baseline characteristics between progression and nonprogression patients did not demonstrate any significant differences. Logistic analysis revealed that only low-density lipoprotein cholesterol (LDL-C) ≥100 mg/dl at follow-up was associated with plaque progression (odds ratio 2.59, 95 % confidence interval 1.12–6.34, P = 0.0263). Cutoff value of LDL-C for plaque progression at follow-up was 103.0 mg/dl based on receiver-operator characteristic curves analyses. Of the 36 progressive lesions in 32 patients, plaque composition at baseline included 13 lesions (36.1 %) of noncalcified plaque, 1 lesion (2.8 %) of calcified plaque, 12 lesions (33.3 %) of partially calcified plaque, and the remaining 10 lesions (27.8 %) had no plaque at baseline and revealed de novo plaques at follow-up. There were 9 lesions (25 %) with high-risk plaque (HRP) characteristics at baseline and 18 lesions (50 %) with HRP at follow-up. Plaque progression of coronary arteries by serial CTA was associated with LDL-C ≥100 mg/dl at follow-up regardless of baseline LDL-C level. There was no specific finding to predict plaque progression on the baseline plaque characteristics.

Two cases with past Kawasaki disease developing acute myocardial infarction in their thirties, despite being regarded as at low risk for coronary events

Two patients after Kawasaki disease (KD) developed acute myocardial infarction in their thirties, though coronary artery follow-up were deemed unnecessary because of apparently angiographic normal coronary arteries in their children more than 1-year after acute KD. Angiographic findings of apparently normal coronary arteries in the late period after acute KD are possible to mislead their prognoses. It should be recognized that coronary aneurysms can often regress in the late period. There is ongoing controversy about the therapeutic strategy in patients whose coronary aneurysms regressed within several years after acute KD. Coronary computed tomography angiography and flow-mediated dilatation might be useful for the detection of mild sequelae of KD non-invasively.

Major bleeding complications related to combined antithrombotic therapy in atrial fibrillation patients 12 months after coronary artery stenting

BACKGROUND AND PURPOSE Many patients with atrial fibrillation (AF) and coronary artery stent deployment are given both antiplatelet drug and warfarin. Little information is available as to the relationship between the antithrombotic therapies in the late phase after stenting and the clinical outcomes of these patients. We examined the clinical outcomes of AF patients 12 months after coronary artery stenting. METHODS We retrospectively examined 146 patients and classified them into three groups according to the antithrombotic therapies [dual antiplatelet therapy (DAPT), single antiplatelet therapy (SAPT) plus warfarin, and DAPT plus warfarin] 12 months after stenting. We defined the primary endpoint as Thrombolysis in Myocardial Infarction major bleeding and the secondary endpoint as a composite of adverse events (CAE: all-cause death, nonfatal myocardial infarction, intracranial bleeding, and cerebral infarction). RESULTS During a median follow-up of 37 months, major bleeding and CAE were observed in 14 (9.6%) and 46 (31.5%) patients, respectively. DAPT plus warfarin was an independent risk factor for major bleeding in a multivariate Cox hazard regression model after adjustment for age, gender, and the type of AF (hazard ratio: 4.20; 95% confidence interval: 1.13-17.27; p=0.033). No significant clinical variables were found for CAE. CONCLUSIONS Prolonged use of DAPT with warfarin significantly increases the risk of major bleeding in AF patients after coronary artery stenting. Individualized antithrombotic treatment is required in these patients to prevent major bleeding.

Multimarker Approach to Risk Stratification for Long-Term Mortality in Patients on Chronic Hemodialysis

BACKGROUND We prospectively investigated the prognostic value of the combined use of cardiac troponin T (TnT), B-type natriuretic peptide (BNP), and high-sensitivity C-reactive protein (CRP) for long-term mortality in hemodialysis (HD) patients. METHODS AND RESULTS: Baseline measurements of TnT, BNP, and CRP were performed in 516 patients on chronic HD. Patients were followed up for 10 years. Using the Cox multivariate model with these 3 biomarkers as variables categorized into tertiles for mortality, a simplified score was obtained by underscoring individual biomarkers based on the adjusted hazard ratio (HR). The multimarker score was defined as the sum of these points. TnT, BNP, and CRP levels were individually independent predictors for mortality (P<0.05). Among low-risk (multimarker score <4), intermediate-risk (multimarker score 4-7), and high-risk (multimarker score ≥7) groups, 10-year survival rates were 83.3%, 54.3%, and 27.2% (P<0.0001), respectively. After adjusting for other confounders, the multimarker score had strong predictive power for mortality (HR: 4.26; P<0.0001 for high-risk vs. low-risk group). Furthermore, adding the multimarker score to a baseline model with established risk factors improved the C-index (P<0.01), net reclassification improvement (P<0.0001), and integrated discrimination improvement (P<0.0001) greater than that of any single biomarker or baseline model alone. CONCLUSIONS The multimarker approach (ie, simultaneous assessment of TnT, BNP, and CRP, which individually independently predict prognosis) may improve the prediction of long-term mortality in HD patients.

A combination of anatomical and functional evaluations improves the prediction of cardiac event in patients with coronary artery bypass.

Objective To study the usefulness of combined risk stratification of coronary CT angiography (CTA) and myocardial perfusion imaging (MPI) in patients with previous coronary-artery-bypass grafting (CABG). Design A retrospective, observational, single centre study. Setting and patients 204 patients (84.3% men, mean age 68.7±7.6) undergoing CTA and MPI. Main outcome measures CTA defined unprotected coronary territories (UCT; 0, 1, 2 or 3) by evaluating the number of significant stenoses which were defined as the left main trunk ≥50% diameter stenosis, other native vessel stenosis ≥70% or graft stenosis ≥70%. Using a cut-off value with receiver-operating characteristics analysis, all patients were divided into four groups: group A (UCT=0, summed stress score (SSS)<4), group B (UCT≥1, SSS<4), group C (UCT=0, SSS≥4) and group D (UCT≥1, SSS≥4). Results Cardiac events, as a composite end point including cardiac death, non-fatal myocardial infarction, unstable angina requiring revascularisation and heart-failure hospitalisation, were observed in 27 patients for a median follow-up of 27.5 months. The annual event rates were 1.1%, 2%, 5.7% and 12.9% of patients in groups A, B, C and D, respectively (log rank p value <0.0001). Adding UCT or SSS to a model with significant clinical factors including left ventricular ejection fraction, time since CABG and Euro SCORE II improved the prediction of events, while adding UCT and SSS to the model improved it greatly with increasing C-index, net reclassification improvement and integrated discrimination improvement. Conclusions The combination of anatomical and functional evaluations non-invasively enhances the predictive accuracy of cardiac events in patients with CABG.

THE RATIO OF SERUM EICOSAPENTAENOIC ACID TO ARACHIDONIC ACID AS A PREDICTOR OF HIGH RISK PLAQUE CHARACTERISTICS ON CORONARY COMPUTED TOMOGRAPHY ANGIOGRAPHY

Computed tomography angiography (CTA)-verified high risk plaque (HRP) characteristics including positive remodeling and low attenuation plaque has been reported as associated with acute coronary syndromes (ACS). On the other hand, several studies reported that the low ratio of eicosapentaenoic acid

309 アスペクト比の小さい Taylor Couette 渦流れの UVP 計測

In this study, experiment was carried out for Taylor-Couette vortex flow. Taylor-Couette vortex flow with small aspect ratio can be generated by two concentric rotating cylinders; a rotating inner cylinder and a fixed outer cylinder. Two test section sizes with radial ratio of 0.375 and 0.667 were applied. Aspect ratio and gap between inner and outer cylinder were kept constant 3 and 25 mm respectively. Successive instantaneous and mean velocity profiles were obtained by using an ultrasonic velocity profiler (UVP). The spatiotemporal velocity field was analysed by two dimensional Fourier transform. In this case, the characteristics of Modulated Wavy Vortex Flow (MVF) and Wavy Vortex Flow (WVF) transition are confirmed. Furthermore, the bifurcations between each cell modes namely the N-2Cell, N-4Cell, A-3Cell and A-4Cell modes are clarified.

Noninvasive Assessment of Stenotic Severity and Plaque Characteristics by Coronary CT Angiography in Patients Scheduled for Carotid Artery Revascularization

Aims: Coronary artery atherosclerosis in patients needing carotid revascularization has not been fully clarified. The aim of this study was to evaluate the stenotic severity and plaque characteristics of coronary arteries by coronary computed tomography angiography (CTA) in patients scheduled for carotid-artery stenting (CAS) or carotid endarterectomy (CEA). Methods: We performed coronary CTA after carotid ultrasound (US) in 164 patients (81.7% male, aged 68.1 ± 12.2 years) from 2014 to 2016. Of all, 70 were scheduled for CAS or CEA (CAS/CEA group) and 94 were not (non-CAS/CEA group). Carotid US and coronary CTA were compared for the evaluation of stenotic severity and plaque characteristics of each vessel between CAS/CEA and non-CAS/CEA groups. Results: Between the two groups, there were significant differences in the presence of significant stenosis (SS: ≥ 70% stenosis of coronary artery) (55.7% vs. 39.4%, P = 0.038), triple-vessel disease (TVD)/left main trunk (LMT) (SS in each of three epicardial vessels and/or LMT) (24.3% vs. 7.5%, P = 0.0025), and high-risk plaque (HRP: positive remodeling and/or low attenuation) (55.7% vs. 24.5%, P < 0.0001). CAS/CEA was independently associated with TVD/LMT (OR = 2.30, 95%CI: 1.14–8.59, P = 0.026) and HRP (OR = 3.17, 95%CI: 1.57–6.54, P = 0.0012) in multivariable logistic regression analysis. Similarly, vulnerable plaque (78.6% vs. 2.1%, P < 0.0001) as well as severe stenosis of carotid artery (98.6% vs. 0%, P < 0.0001) was seen more often in CAS/CEA than in non-CAS/CEA group. Conclusions: The prevalence of TVD/LMT and HRP determined by coronary CTA is higher in patients needing CAS/CEA than in those without. Management of systemic atherosclerosis is required in the perioperative period of CAS/CEA.