Ryo Okubo
Toho University
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Featured researches published by Ryo Okubo.
Journal of Interventional Cardiology | 2015
Hideo Amano; Takanori Ikeda; Mikihito Toda; Ryo Okubo; Takayuki Yabe; Makiko Koike; Daiga Saito; Junichi Yamazaki
OBJECTIVES We assessed the relation between coronary plaque composition and angiographic calcification by using virtual histology intravascular ultrasound (VH-IVUS). BACKGROUND The plaque vulnerability according to angiographic calcification is unclear. METHODS Subjects were 140 consecutive patients (145 lesions) undergoing VH-IVUS before percutaneous coronary intervention. Subjects were divided into 4 groups: no calcification group (n = 27), spotty group (n = 65) that had calcium deposits under 90° in grayscale IVUS, intermediate group (n = 37) had calcium deposits with 90° or more and under 180°, and extensive group (n = 16) had calcium deposits with 180° or more. RESULTS The number of VH thin-cap fibroatheromas in spotty group was significantly larger than no calcification group, intermediate group, and extensive group (0.66 ± 0.71 vs 0.22 ± 0.42 [P < 0.01], 0.32 ± 0.48 [P < 0.05], 0.13 ± 0.34 [P < 0.01], respectively). Spotty group without angiographic calcification had significantly larger %necrotic core than with angiographic calcification (24.5 ± 6.7% vs 19.9 ± 7.2%, P < 0.05). Intermediate group without angiographic calcification had significantly larger necrotic core area than with angiographic calcification (2.5 ± 0.9 mm(2) vs 1.7 ± 0.9 mm(2) , P < 0.05). Extensive group with angiographic calcification had significantly larger %dense calcium than without angiographic calcification (18.3 ± 4.0% vs 13.4 ± 4.4%, P < 0.05). CONCLUSIONS Lesions with spotty calcification was highly vulnerable in VH-IVUS. Spotty or intermediate plaque calcification without angiographic calcification was more vulnerable than those with angiographic calcification. Extensive plaque calcification with angiographic calcification had more dense calcium than those without angiographic calcification.
Heart and Vessels | 2017
Ryo Okubo; Rine Nakanishi; Mikihito Toda; Daiga Saito; Ippei Watanabe; Takayuki Yabe; Hideo Amano; Tatsushi Hirai; Takanori Ikeda
This study was designed to clarify the influence of pericoronary adipose tissue (PAT) on plaque vulnerability using coronary computed tomography angiography (CCTA). A total of 103 consecutive patients who underwent CCTA and subsequent percutaneous coronary intervention (PCI) using intravascular ultrasound (IVUS) for coronary artery disease were enrolled. The PAT ratio was calculated as the sum of the perpendicular thickness of the visceral layer between the coronary artery and the pericardium, or the coronary artery and the surface of the heart at the PCI site, divided by the PAT thickness without a plaque in the same vessel. PAT ratios were divided into low, mid and high tertile groups. Epicardial adipose tissue (EAT) thickness was measured at the eight points surrounding the heart. Multivariate logistic analysis was performed to determine whether the PAT ratio is predictive of vulnerable plaques (positive remodeling, low attenuation and/or spotty calcification) on CCTA or echo-attenuated plaque on IVUS. The Hounsfield unit of obstructive plaques >50% was lower in the high PAT group than in the mid and low PAT groups (47.5 ± 28.8 vs. 53.1 ± 29.7 vs. 64.7 ± 27.0, p = 0.04). In multivariate logistic analysis, a high PAT ratio was an independent, associated factor of vulnerable plaques on CCTA (OR: 3.55, 95% CI: 1.20–10.49), whereas mean EAT thickness was not (OR: 1.22, 95% CI: 0.82–1.83). We observed a similar result in predicting echo-attenuated plaque on IVUS. PAT ratio on CCTA was an associated factor of vulnerable plaques, while EAT was not. These results support the important concept of local effects of cardiac adipose tissue on plaque vulnerability.
International Heart Journal | 2016
Hideo Amano; Takanori Ikeda; Mikihito Toda; Ryo Okubo; Takayuki Yabe; Ippei Watanabe; Daiga Saito
It has been reported that coronary vasa vasorum is associated with plaque vulnerability, and low-echoic structures in grayscale intravascular ultrasound (IVUS) are consistent pathologically with vasa vasorum. However, the association of low-echoic structures with plaque composition and no-reflow phenomenon during percutaneous coronary intervention (PCI) is unclear. We investigated plaque composition in virtual histology IVUS (VH-IVUS) and no-reflow phenomenon during PCI of low-echoic structures.A total of 106 lesions being treated by VH-IVUS before PCI were included in this study. Low-echoic structure was defined as a small tubular structure exterior to media without a connection to the vessel lumen in ≥ 3 consecutive crosssectional IVUS images. Lesions with low-echoic structures were found in 42% (45/106).Lesions with low-echoic structures were more prevalent in acute coronary syndrome (ACS) patients (53% [24/45] versus 20% [12/61], P < 0.001), had more positive remodeling (49% [22/45] versus 21% [13/61], P = 0.003), a larger number of VH-IVUS derived thin-cap fibroatheromas (VH-TCFAs) (0.64 ± 0.53 versus 0.05 ± 0.22, P < 0.001), more VH-TCFAs with a baseline plaque burden of 70% or more and minimal luminal area of 4.0 mm(2) or less (29% [13/45] versus 2% [1/61], P < 0.001), and more frequent no-reflow phenomenon after stent implantation and more final TIMI flow grade 0/1/2 (38% [17/45] versus 5% [3/61], P < 0.001; 9% [4/45] versus 0% [0/61], P = 0.03) than lesions without low-echo structures.Lesions with low-echoic structures in grayscale IVUS had high plaque vulnerability and were more prevalent in ACS patients, positive remolding, and VH-TCFAs, and they had more frequent no-reflow phenomenon during PCI than lesions without low-echoic structures.
Journal of Atherosclerosis and Thrombosis | 2018
Ippei Watanabe; Junko Tatebe; Takahiro Fujii; Ryota Noike; Daiga Saito; Hideki Koike; Takayuki Yabe; Ryo Okubo; Rine Nakanishi; Hideo Amano; Mikihito Toda; Takanori Ikeda; Toshisuke Morita
Aim: We investigated whether indoxyl sulfate (IS), a protein-bound uremic toxin, predicts prognosis after acute coronary syndrome (ACS). Methods: Serum IS level was determined prospectively in 98 patients who underwent successful primary percutaneous coronary intervention for ACS. Patients on hemodialysis were excluded. The endpoint of this study was six-month composite events including death, nonfatal myocardial infarction, heart failure requiring hospitalization, and adverse bleeding events. Results: During the mean follow-up period of 168 days, composite events occurred in 13.3% of cases. Serum IS level was significantly higher in subjects who developed composite events than in those without events (0.14 ± 0.11 mg/dl vs. 0.06 ± 0.04 mg/dl; p < 0.001). After adjusting for confounding factors, a Cox proportional hazard analysis revealed that the IS level (hazard ratio (HR): 10.6; 95% confidence interval (CI): 1.63–69.3, p = 0.01), hemoglobin level (HR: 0.61; 95% CI: 0.43–0.87; p < 0.01), and left ventricular ejection fraction (LVEF) (HR: 0.95; 95% CI: 0.91–0.99; p = 0.03) were independent predictive factors of composite events. Furthermore, IS level significantly conferred additional value to the combined established risks of LVEF and hemoglobin level for predicting the incidence of composite events (area under the curve: 0.82 vs. 0.88, p = 0.01; net reclassification improvement: 0.67, p = 0.01; and integrated discrimination improvement: 0.15, p < 0.01). Conclusions: The assessment of serum IS level has prognostic utility for the management of ACS.
Journal of the American College of Cardiology | 2017
Daiga Saito; Ippei Watanabe; Rine Nakanishi; Mikihito Toda; Hideo Amano; Ryo Okubo; Takayuki Yabe; Takanori Ikeda
Background: In patients with ST-segment elevation myocardial infarction (STEMI), left ventricular systolic function (LVSF) is associated with prognosis. In the present study, we sought to examine the clinical implication of left ventricular end-diastolic pressure (LVEDP) in patients with STEMI with
Journal of Cardiology | 2017
Takayuki Yabe; Mikihoto Toda; Rine Nakanishi; Daiga Saito; Ippei Watanabe; Ryo Okubo; Hideo Amano; Takanori Ikeda
BACKGROUND The treatment strategy for in-stent restenosis (ISR) with bifurcation lesions has not been well explored. We examined the clinical outcomes between final kissing balloon technique (FKBT) after stent implantation and single-stent implantation without FKBT for bifurcation ISR lesions. METHODS We identified 115 consecutive ISR with bifurcation lesions among 108 patients who underwent drug-eluting stent implantation. The patients were divided into the FKBT group (34 patients, 35 lesions) and the non-FKBT group (74 patients, 80 lesions). RESULTS Thrombolysis in myocardial infarction flow grade of side branch was significantly greater in the patients with FKBT than those without FKBT after coronary intervention (2.80±0.46 vs. 2.65±0.68, p=0.04), but this difference was attenuated and was no longer statistically significant at the time of follow-up (2.80±0.48 vs. 2.80±0.60, p=0.97). During a mean follow-up of 47.8±23.6 months, there were no significant differences in the incidence of major adverse cardiac events (MACE). In multivariate analysis, estimated glomerular filtration rate (hazard ratio: 0.96, 95% confidence interval: 0.92-0.99, p=0.02) was an independent predictor of MACE. Contrast volume (170.71±47.17ml vs. 136.46±55.56ml, p=0.002) and radiation dose (1.44±1.65Gy vs. 0.96±0.46Gy, p=0.02) were significantly higher in the FKBT group than in the non-FKBT group. CONCLUSIONS Single-stent implantation without FKBT may be a sufficient treatment strategy for bifurcation ISR lesions.
International Heart Journal | 2017
Hideo Amano; Daiga Saito; Takayuki Yabe; Ryo Okubo; Mikihito Toda; Takanori Ikeda
The efficacy and safety of direct oral anticoagulants (DOAC) with antiplatelet therapy compared to warfarin are unclear. The subjects were 280 patients who received antiplatelet therapy with oral anticoagulation (OAC) for the treatment of or protection from thromboembolism between January 2012 and September 2015. Among the 280 subjects, 79 (28.2%) received dual therapy (OAC plus aspirin or P2Y12 inhibitor) with DOAC, 75 (26.8%) dual therapy with warfarin, 46 (16.4%) triple therapy (OAC plus aspirin and P2Y12 inhibitor) with DOAC, and 80 (28.6%) triple therapy with warfarin.Compared to triple therapy with warfarin, triple therapy with DOAC had slightly lower bleeding (3.5 versus 12.0/100 persons-years, HR: 0.24, 95%CI: 0.03 to 1.96, P = 0.183), and similar benefit outcomes (cardiac death, acute myocardial infarction or stroke) and thromboembolism (7.0 versus 10.5, HR: 0.53, 95%CI: 0.10 to 2.75, P = 0.453; 7.0 versus 7.5, HR: 0.96, 95%CI: 0.18 to 5.22, P = 0.964, respectively). Compared to dual therapy with warfarin, dual therapy with DOAC had slightly lower bleeding (3.0 versus 8.4, HR: 0.38, 95%CI: 0.07 to 2.18, P = 0.279), and similar benefit outcomes and thromboembolism (4.6 versus 4.2, HR: 1.66, 95%CI: 0.30 to 9.25, P = 0.565; 4.6 versus 1.4, HR: 3.11, 95%CI: 0.23 to 42.84, P = 0.397, respectively). Bleeding mainly occurred after 3 months (16/17, 94.1%).Triple therapy and dual therapy with DOAC were not inferior to triple therapy and dual therapy with warfarin in terms of major bleeding, benefit outcomes, and thromboembolism. Bleeding mainly occurred in the late phase.
Journal of the American College of Cardiology | 2016
Ippei Watanabe; Rine Nakanishi; Shingo Matsumoto; Shintaro Dobashi; Takayuki Yabe; Ryo Okubo; Hideo Amano; Mikihito Toda; Takanori Ikeda
The definition of acute kidney injury (AKI) has been currently changing. The aim of this study is to evaluate whether the two different definitions of conventional contrast induced nephropathy (CIN) and a novel contrast-induced AKI (CI-AKI) (Kidney Disease: Improving Global Outcomes (KDIGO) for
Journal of the American College of Cardiology | 2016
Shingo Matsumoto; Ippei Watanabe; Takayuki Yabe; Ryo Okubo
In the present study, we assessed the association between heart rate (HR) after success of resuscitation from out-of-hospital cardiac arrest (OHCA) due to acute coronary syndrome (ACS) and their outcomes. The clinical data from 3,687 OHCA patients between October 2002 and October 2014 were
Journal of the American College of Cardiology | 2016
Ryo Okubo; Mikihito Toda; Ippei Watanabe; Takayuki Yabe; Hideo Amano; Rine Nakanishi; Ikeda Takanori
Epicardial adipose tissue (EAT) measurement, using coronary computed tomography angiography (CCTA) has been shown to be linked with coronary atherosclerosis. However, little is known about the relationship between pericoronary fat and plaque morphology. The aim of this study was to clarify the