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Dive into the research topics where Tomoo Nakata is active.

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Featured researches published by Tomoo Nakata.


Jacc-cardiovascular Interventions | 2013

Elevated levels of systemic pentraxin 3 are associated with thin-cap fibroatheroma in coronary culprit lesions: assessment by optical coherence tomography and intravascular ultrasound.

Seiji Koga; Satoshi Ikeda; Takeo Yoshida; Tomoo Nakata; Masayoshi Takeno; Nobuhito Masuda; Yuji Koide; Hiroaki Kawano; Koji Maemura

OBJECTIVES This study sought to determine whether systemic levels of pentraxin 3 (PTX3), a novel inflammatory marker, are associated with thin-cap fibroatheroma (TCFA). BACKGROUND Biomarkers predicting the presence of TCFA in vivo have not been established. METHODS We evaluated 75 patients (stable angina pectoris, n = 47; acute coronary syndrome, n = 28) with de novo culprit lesions who were examined by optical coherence tomography and intravascular ultrasound. We defined TCFA as lipid-rich plaque with a fibrous cap <65 μm thick. Systemic levels of PTX3 were compared between patients with and without TCFA. RESULTS Thirty-eight and 37 patients with and without TCFA, respectively, were identified. Levels of PTX3 were significantly higher in patients with than in those without TCFA (p < 0.001) and correlated inversely with fibrous cap thickness (r = -0.71, p = 0.001) and positively with the remodeling index (r = 0.25, p = 0.037). Multivariate logistic regression analysis showed that a higher PTX3 level was the most powerful predictor of TCFA (odds ratio: 3.26, 95% confidence interval: 1.75 to 6.05, p < 0.001). Receiver-operating characteristic curve analysis showed that >3.24 ng/ml of PTX3 could predict TCFA with 84% sensitivity and 86% specificity. CONCLUSIONS Higher levels of systemic PTX3 are associated with TCFA. Systemic PTX3 levels comprise a useful inflammatory marker that reflects coronary plaque vulnerability.


International Heart Journal | 2015

Impact of Catheter Sheath Insertion into the Radial Artery on Vascular Endothelial Function Assessed by Reactive Hyperemia Peripheral Arterial Tonometry

Tomoo Nakata; Satoshi Ikeda; Seiji Koga; Takeo Yoshida; Yuji Koide; Hiroaki Kawano; Koji Maemura; Shigeru Kohno

The transradial approach has been used for coronary procedures, but this procedure carries a risk of injury to the endothelium of the radial artery. In this study, the vascular dysfunction caused by transradial catheterization was examined using reactive hyperemia peripheral arterial tonometry (RH-PAT), a recently developed technique for assessing endothelial function in digits, and the differences in injuries were compared according to the size of sheath.Forty-three patients undergoing transradial catheterization with 6-Fr sheaths (n = 17) or 4-Fr/5-Fr (non-6-Fr; n = 26) sheaths underwent RH-PAT using an Endo-PAT2000 before, the day after, and 6 months after catheterization. RH-PAT was assessed in the arm of sheath placement and in the other arm as a control.RH-PAT values decreased from 2.42 ± 0.67 before catheterization to 2.08 ± 0.41 the day after catheterization in the 6-Fr group (P = 0.031); this was more evident in patients with a longer procedure time (> 91 minutes). In contrast, the change in the non-6-Fr group was not significant. RH-PAT of the non-catheterized arm was unchanged in both groups. At 6 months after catheterization, RH-PAT values in the 6-Fr group had not completely returned to baseline.In conclusion, the insertion of a 6-Fr catheter sheath into the radial artery, especially with a longer procedure time, impaired vascular endothelial function assessed by RH-PAT the day after the procedure and was sustained for 6 months. Thus, the use of smaller size sheaths (< 6-Fr) with a shorter procedure should be considered when performing transradial catheterization.


Circulation | 2015

iMap-Intravascular Ultrasound Radiofrequency Signal Analysis Reflects Plaque Components of Optical Coherence Tomography-Derived Thin-Cap Fibroatheroma

Seiji Koga; Satoshi Ikeda; Miyuki Miura; Takeo Yoshida; Tomoo Nakata; Yuji Koide; Hiroaki Kawano; Koji Maemura

BACKGROUND The ability of iMap-intravascular ultrasound (IVUS) tissue characterization to detect thin-cap fibroatheroma (TCFA) identified on optical coherence tomography (OCT) has not yet been fully elucidated. METHODSANDRESULTS We evaluated 86 coronary lesions from 73 patients with stable angina pectoris using iMap-IVUS and OCT. We defined OCT-derived TCFA (OCT-TCFA) as lipid-rich plaque with a <65-μm-thick fibrous cap. The external elastic membrane (EEM) cross-sectional area (CSA), lumen CSA, plaque plus media (P+M) CSA, plaque burden and remodeling index were measured on gray-scale IVUS. Plaque components categorized on iMap-IVUS as fibrotic, lipidic, necrotic or calcified are presented as absolute area and proportion (%) of total plaque area. OCT-TCFA (22 lesions) had significantly greater EEM CSA, P+M CSA, plaque burden and remodeling index than non-TCFA (64 lesions). Significantly larger %necrotic area, absolute lipidic and necrotic areas and smaller %fibrotic areas were found in OCT-TCFA than in non-TCFA. On multivariate analysis, absolute necrotic area was an independent predictor of OCT-TCFA. The area under the ROC curve for absolute necrotic area required to identify OCT-TCFA was 0.86. The sensitivity, specificity, positive and negative predictive values of absolute necrotic area ≥7.3 mm2 for identifying OCT-TCFA were 77%, 88%, 68% and 92%, respectively. CONCLUSIONS Coronary lesions with greater iMap-IVUS absolute necrotic area were closely associated with OCT-TCFA.


Life Sciences | 2014

Longitudinal strain of right ventricular free wall by 2-dimensional speckle-tracking echocardiography is useful for detecting pulmonary hypertension

Satoshi Ikeda; Akira Tsuneto; Sanae Kojima; Seiji Koga; Tomoo Nakata; Takeo Yoshida; Miyuki Eto; Takako Minami; Katsunori Yanagihara; Koji Maemura

AIMS Echocardiography is widely used for screening pulmonary hypertension (PH). More recently developed two-dimensional speckle-tracking echocardiography (2D-STE) can assess regional deformation of the myocardium and is useful for detecting left ventricular dysfunction. However, its usefulness to assess right ventricular (RV) dysfunction is not clear. Therefore, the aim of this study was to investigate the ability of peak systolic strain (PSS) and post-systolic strain index (PSI) at the RV free wall determined by 2D-STE to detect PH. MAIN METHODS Thirty-six images (27 images from PH patients, nine from patients with connective tissue disease without PH) obtained by 2D-STE were analysed. We investigated the relationship between RV hemodynamics measured by right heart catheterization and PSS, PSI and other echocardiographic parameters reflecting RV overload including RV end-diastolic diameter (RVDd) and tricuspid valve regurgitant pressure gradient (TRPG). KEY FINDINGS PSS, PSI, RVDd and TRPG were all correlated with mean pulmonary arterial pressure (MPAP) and pulmonary vascular resistance (PVR). Furthermore, when PSS and MPAP were measured twice, the change in PSS was correlated with the change in MPAP (r=0.633, p=0.037). Multivariate logistic regression analysis identified PSS as the only independent factor associated with MPAP ≥ 35mmHg [odds ratio (OR), 1.616; 95% confidence interval (CI) 1.017-2.567; p=0.042] and PVR ≥ 400dyn·s·cm(-5) (OR, 1.804; 95% CI 1.131-2.877; p=0.013). Furthermore, the optimal PSS cut-off value to detect an elevated MPAP and PVR was -20.75%, based on receiver operating characteristic curve analysis. SIGNIFICANCE PSS of the RV free wall might serve as a useful non-invasive indicator of PH.


European Journal of Radiology | 2016

Quantification of lung perfusion blood volume (lung PBV) by dual-energy CT in patients with chronic thromboembolic pulmonary hypertension (CTEPH) before and after balloon pulmonary angioplasty (BPA): Preliminary results.

Hirofumi Koike; Eijun Sueyoshi; Ichiro Sakamoto; Masataka Uetani; Tomoo Nakata; Kouji Maemura

OBJECTIVES Balloon pulmonary angioplasty (BPA) is a treatment option for patients with chronic thromboembolic pulmonary hypertension (CTEPH). Its effect on pulmonary perfusion has not been quantified; we examined the clinical significance of pulmonary blood volume (PBV) using dual-energy computed tomography (DECT) in patients with CTEPH undergoing BPA. METHODS In this retrospective study of 16 BPAs in eight female patients with CTEPH, we evaluated both-lung (n=16), right- or left-lung (n=32), and three right- or left-segment (upper, middle, and lower) (n=96) PBVs before and after BPA, using DECT. We evaluated the relationships between improvement in lung PBV and pulmonary artery (PA) pressure (PAP), cardiac index (CI), pulmonary vascular resistance (PVR), and 6-min walking distance. We measured PA enhancement (PAenh) on DECT images and calculated lung PBV/PAenh to adjust timing. RESULTS Pre- and post-BPA 6-segment lung PBV/PAenh were 0.067±0.021 and 0.077±0.019, respectively, in the treated segment (p<0.0001). There were significant positive correlations between pre- to post-BPA improvements in both-lung PBV/PAenh and PAP (R=0.69, p=0.005), PVR (R=0.56, p=0.03), and 6-min walking distance (R=0.67, p=0.01). CONCLUSIONS Improved PBV after BPA, reflecting increased lung perfusion, was positively correlated with PAP, PVR, and 6-min walking distance. Lung PBV may be an indicator of BPA treatment effect.


International Heart Journal | 2015

Diverse Findings in Calcified Thrombus Between Histopathology and In Vivo Imaging Including Intravascular Ultrasound, Optical Coherence Tomography, and Angioscopy

Seiji Koga; Satoshi Ikeda; Tomoo Nakata; Hiroaki Kawano; Kuniko Abe; Koji Maemura

A 46-year-old woman on hemodialysis due to end-stage renal disease was admitted for repeated thrombus formation in previously implanted drug-eluting stents in the right coronary artery. We could successfully aspirate this thrombus, and histopathology revealed a calcified thrombus comprising multiple microcalcifications and fibrinous materials. This is the first report showing how a calcified thrombus is visualized in vivo by intracoronary imaging modalities including intravascular ultrasound, optical coherence tomography, and angioscopy.


Internal Medicine | 2015

Coronary Artery Pseudoaneurysm due to Medial Mucoid Degeneration Mimicking an Intra-atrial Mass

Tomohiro Honda; Hiroaki Kawano; Akira Tsuneto; Tomoo Nakata; Takeo Yoshida; Seiji Koga; Satoshi Ikeda; Kuniko Abe; Tomayoshi Hayashi; Shogo Yokose; Kiyoyuki Eishi; Koji Maemura

Coronary artery aneurysms are frequently asymptomatic and may be difficult to diagnose by cardiac imaging. We herein present a case of a coronary artery aneurysm of the right coronary artery due to medial mucoid degeneration mimicking an intra-atrial mass on echocardiography and magnetic resonance imaging, with the cause being diagnosed after surgery.


European Radiology | 2018

Comparative clinical and predictive value of lung perfusion blood volume CT, lung perfusion SPECT and catheter pulmonary angiography images in patients with chronic thromboembolic pulmonary hypertension before and after balloon pulmonary angioplasty

Hirofumi Koike; Eijun Sueyoshi; Ichiro Sakamoto; Masataka Uetani; Tomoo Nakata; Kouji Maemura

AbstractObjectivesLung perfusion blood volume (PBV) using dual-energy computed tomography has recently become an accepted technique for diagnosing pulmonary thromboembolism. We evaluated the correlation among lung PBV, single-photon emission computed tomography (SPECT) and catheter pulmonary angiography images in patients with chronic thromboembolic pulmonary hypertension (CTEPH) before and after balloon pulmonary angioplasty (BPA).MethodsIn total, 17 patients and 57 sessions were evaluated with the three modalities. Segmental lung perfusion and its improvement in lung PBV and SPECT were compared with catheter pulmonary angiography as the reference standard before and after BPA.ResultsThe sensitivity for detecting segmental perfusion defects using SPECT and lung PBV was 85% and 92%, the specificity was 99% and 99%, the accuracy was 92% and 95%, the positive predictive value was 99% and 99%, and the negative predictive value was 88% and 93%. The sensitivity for detecting segmental perfusion improvement using SPECT and lung PBV was 61% and 69%, the specificity was 75% and 83%, the accuracy was 62% and 70%, the positive predictive value was 97% and 98%, and the negative predictive value was 12% and 16%.ConclusionsLung PBV is a useful technique for evaluation of segmental lung perfusion and its improvement in patients with CTEPH.Key Points• BPA is a new treatment for patients with CTEPH.• Lung PBV images may be more sensitive for pulmonary blood flow.• The current work demonstrates that Lung PBV images are useful in evaluating patients with CTEPH. • The current work demonstrates that Lung PBV is useful in gauging the treatment effect of BPA.


Internal Medicine | 2017

Cardiac Calcified Amorphous Tumors in a Patient with Hemodialysis for Diabetic Nephropathy

Satoshi Yoshimura; Hiroaki Kawano; Takako Minami; Akira Tsuneto; Tomoo Nakata; Seiji Koga; Satoshi Ikeda; Tomayoshi Hayashi; Koji Maemura

Calcified amorphous tumor (CAT) is a rare, non-neoplastic tumor involving calcium deposition in amorphous materials. Although its etiology is unknown, cases have frequently been reported in patients with hemodialysis for chronic kidney disease. We herein describe a case of cardiac CAT in a 64-year-old woman who had been on hemodialysis for diabetic nephropathy for 20 years, and the findings of the present patient, in association with the findings of previous case reports, suggest that end-stage renal disease seems to play an important role in the onset of CAT, especially in CAT formation at the mitral annulus, which appears to differ from CAT occurring at other sites.


Internal Medicine | 2017

The Histological Features of a Myocardial Biopsy Specimen in a Patient in the Acute Phase of Reversible Catecholamine-induced Cardiomyopathy due to Pheochromocytoma

Miyuki Miura; Hiroaki Kawano; Takeo Yoshida; Yuki Yamagata; Tomoo Nakata; Seiji Koga; Satoshi Ikeda; Kan Kageyama; Kuniko Abe; Koji Maemura

A 63-year-old Japanese woman with an adrenal tumor was transferred to our hospital due to cardiogenic shock. Right and left ventriculography showed severe hypokinesis of the middle segment and the apex in both ventricles, and an endomyocardial biopsy demonstrated a small number of necrotic myocytes and cellular infiltration. She was diagnosed with pheochromocytoma and quickly recovered after treatment with an α-blocker. The functional disability of both the right and left ventricles with less myocardial damage due to an excessive level of catecholamine seemed to be related to the early recovery the present patient with catecholamine-induced cardiomyopathy due to pheochromocytoma.

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