Nobuyasu Yamamoto
Kumamoto University
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Featured researches published by Nobuyasu Yamamoto.
Hypertension | 2002
Nobuyasu Yamamoto; Hirofumi Yasue; Yuji Mizuno; Michihiro Yoshimura; Hiromi Fujii; Masafumi Nakayama; Eisaku Harada; Shota Nakamura; Teruhiko Ito; Hisao Ogawa
This study was designed to examine whether aldosterone is produced from the hearts of patients with essential hypertension without left ventricular systolic dysfunction (LVSD). The study population consisted of 20 patients with essential hypertension without LVSD and 22 control subjects. Plasma levels of aldosterone, serum ACE activity, and B-type natriuretic peptide levels were measured in the anterior interventricular vein (AIV), coronary sinus, and aortic root during cardiac catheterization. The plasma aldosterone levels were significantly higher in AIV and coronary sinus than in aortic root (99±11 versus 88±10 pg/mL, P <0.01, and 100±12 versus 88±10 pg/mL, P <0.01, respectively) in the hypertension group. On the other hand, there were no significant differences in aldosterone levels for these sites in the control group. There were no significant differences in ACE activity levels between aortic root, AIV, and coronary sinus in either the hypertension or control group. The levels of B-type natriuretic peptide were significantly higher in AIV than in aortic root in both groups. The difference in aldosterone levels between AIV and aortic root (&Dgr; Aldo[AIV−Ao]) had a significant positive correlation with the difference in ACE activity between AIV and aortic root (&Dgr;ACE[AIV−Ao]) (r =0.501, P <0.05) in the hypertension group. Both &Dgr; Aldo[AIV−Ao] and &Dgr;ACE[AIV−Ao] had a significant positive correlation with diastolic blood pressure (r =0.498, P <0.05;r =0.577, P <0.01, respectively) in the hypertension group. We conclude that production of aldosterone is activated in the left ventricles in patients with essential hypertension without LVSD in proportion to the severity of hypertension.
American Journal of Cardiology | 2002
Yuji Mizuno; Hirofumi Yasue; Michihiro Yoshimura; Hiromi Fujii; Nobuyasu Yamamoto; Masafumi Nakayama; Eisaku Harada; Tomohiro Sakamoto; Shota Nakamura; Teruhiko Ito; Yukio Shimasaki; Hisao Ogawa; Yoshihiko Saito; Kazuwa Nakao
The present study was designed to examine whether the production of aldosterone from the heart is suppressed by angiotensin-converting enzyme (ACE) inhibition in patients with heart failure. Forty-one patients with left ventricular systolic dysfunction were randomly divided into either the perindopril group (n = 21, perindopril 4 mg/day) or the placebo group (n = 20). Plasma levels of aldosterone and ACE activity were measured in the anterior interventricular vein, coronary sinus, and aortic root during cardiac catheterization. The levels of aldosterone as well as ACE activity were significantly higher at the anterior interventricular vein and the coronary sinus than at the aortic root in the placebo group (aldosterone: 92.1 +/- 9.0 vs 70.6 +/- 8.3 pg/ml [p <0.001]; 90.3 +/- 9.2 vs 70.6 +/- 8.3 pg/ml [p <0.001], respectively; ACE activity: 13.6 +/- 0.8 vs 12.2 +/- 0.7 IU/L [p <0.001], 13.4 +/- 0.8 vs 12.2 +/- 0.7 IU/L [p <0.001], respectively). On the other hand, there were no differences in the levels of aldosterone or ACE activity between the anterior interventricular vein and aortic root or between the coronary sinus and aortic root (aldosterone: 68.1 +/- 8.4 vs 69.9 +/- 9.4 pg/ml [p = NS]; 67.3 +/- 8.9 vs 69.9 +/- 9.4 pg/ml [p = NS], respectively; ACE activity: 9.7 +/- 0.8 vs 9.9 +/- 0.8 IU/L [p = NS]; 9.8 +/- 0.8 vs 9.9 +/- 0.8 IU/L, respectively) in the perindopril group. The levels of aldosterone as well as ACE activity were significantly lower at the anterior interventricular vein and coronary sinus in the perindopril group than in the placebo group. The difference in the level of aldosterone between the anterior interventricular vein and aortic root (Delta aldosterone [anterior interventricular vein - aortic root]) had a significant positive correlation with that of ACE activity (Delta ACE [anterior interventricular vein - aortic root]) (r = 0.536, p <0.001), whereas ACE activity in the aortic root had no significant correlation with either the aldosterone levels in the aortic root or Delta aldosterone (anterior interventricular vein - aortic root). Perindopril suppressed cardiac aldosterone production by mainly suppressing cardiac ACE activity in patients with heart failure. Thus, aldosterone production is activated in the failing ventricle and is suppressed by perindopril mainly via the suppression of cardiac ACE activity in patients with heart failure.
Circulation | 2015
Masanobu Ishii; Seiji Hokimoto; Tomonori Akasaka; Kazuteru Fujimoto; Yuji Miyao; Koichi Kaikita; Shuichi Oshima; Koichi Nakao; Hideki Shimomura; Ryusuke Tsunoda; Toyoki Hirose; Ichiro Kajiwara; Toshiyuki Matsumura; Natsuki Nakamura; Nobuyasu Yamamoto; Shunichi Koide; Hideki Oka; Yasuhiro Morikami; Naritsugu Sakaino; Kunihiko Matsui; Hisao Ogawa
BACKGROUND The aim of this study was to examine the effects of different statins on the clinical outcomes of Japanese patients with coronary stent implants. METHODS AND RESULTS This study included 5,801 consecutive patients (males, 4,160; age, 69.7±11.1 years, mean±SD) who underwent stent implantation between April 2008 and March 2011. They were treated with a strong statin (n=3,042, 52%, atorvastatin, pitavastatin, or rosuvastatin), a regular statin (n=1,082, 19%, pravastatin, simvastatin, or fluvastatin) or no statin (n=1,677, 29%). The patients with chronic kidney disease (CKD) were divided into mild-to-moderate CKD (30≤eGFR<60, n=1,956) and severe CKD (eGFR <30, n=559). Primary endpoints included cardiovascular death and nonfatal myocardial infarction, including stent thrombosis and ischemic stroke. The clinical outcome for the primary endpoint in mild-to-moderate CKD patients treated with a strong statin (hazard ratio 0.50, 95% confidence interval 0.31-0.81; P=0.005) was significantly lower than in those on no statins, but that in the patients treated with a regular statin was not (P=0.160). The clinical outcome for the primary endpoint in severe CKD patients treated with a strong or regular statin was no different than not being on statin therapy (P=0.446, P=0.194, respectively). CONCLUSIONS In patients with mild-to-moderate CKD, only strong statins were associated with lower risk compared with no statin, but regular statins were not. It is possible that taking a strong statin from the early stage of CKD is useful for suppression of cardiovascular events.
International Journal of Cardiology | 2000
Nobuyasu Yamamoto; Hisao Ogawa; Shuichi Oshima; Hirofumi Soejima; Hiromi Fujii; Kenji Misumi; Keiji Takazoe; Yuji Mizuno; Katsuo Noda; Taro Saito; Ichiro Tsuji; Kousuke Kumeda; Shin Nakamura; Hirofumi Yasue
We examined plasma TF and free TFPI levels in 26 consecutive patients with AMI, 26 patients with stable exertional angina, and 25 patients with chest pain syndrome. In patients with AMI, blood samples were obtained immediately after admission and at 4, 8, 16, 24, and 48 h, and the third, fifth, seventh, and fourteenth day after initiation of reperfusion therapy. Plasma TF levels in patients with AMI on admission were significantly higher than in the chest pain syndrome and stable exertional angina groups (248.0+/-117. 4 vs. 179.5+/-29.2 vs. 189.5+/-29.6 pg/ml, P<0.01). In patients with AMI, the level subsequently decreased after heparin administration and was maintained at significantly lower levels compared to those on admission. Plasma free TFPI levels in patients with AMI on admission were significantly higher than in the chest pain syndrome and stable exertional angina groups [33.5+/-12.4 vs. 26.0+/-7.6 ng/ml (P<0.01) vs. 27.5+/-6.3 ng/ml, P<0.05]. In patients with AMI, it reached the maximum level at 4 h after the administration of heparin, and gradually decreased over the time course. These data indicated that continuous administration of a low dose of heparin was effective in decreasing TF levels without affecting TFPI levels. Our results elucidate one of the mechanisms by which the administration of heparin is beneficial in AMI patients undergoing percutaneous revascularization.
Journal of Hypertension | 2005
Yuji Mizuno; Hirofumi Yasue; Michihiro Yoshimura; Eisaku Harada; Hiromi Fujii; Shota Nakamura; Nobuyasu Yamamoto; Hisao Ogawa; Kazuwa Nakao
Objective Aldosterone is produced in the ventricle of patients with hypertension. The present study was designed to examine whether adrenocorticotropic hormone (ACTH) and cortisol are also produced from the heart in patients with essential hypertension. Methods The study population consisted of 57 patients with essential hypertension and 28 control subjects. Plasma levels of ACTH, aldosterone, and cortisol were measured in the aortic root, the anterior interventricular vein and the coronary sinus during cardiac catheterization. Results The plasma levels of ACTH were significantly higher at the anterior interventricular vein and coronary sinus than at the aortic root (12.7 ± 1.0 versus 10.7 ± 0.9 pmol/l, P < 0.001; and 12.3 ± 1.0 versus 10.7 ± 0.9 pmol/l, P <, respectively) in the hypertension group, whereas there were no significant differences in the levels among these sites in the control group. The plasma levels of aldosterone were significantly higher at the anterior interventricular vein and the coronary sinus than at the aortic root (261.7 ± 16.4 versus 239.1 ± 15.1 pmol/l, P < 0.001; and 258.8 ± 17.0 versus 239.1 ± 15.1 pmol/l, P < 0.01, respectively) in the hypertension group, whereas there were no significant differences in the levels among these sites in the control group. Conclusions ACTH as well as aldosterone is produced, but cortisol is not produced, from the ventricle of patients with essential hypertension.
American Journal of Cardiology | 1999
Taro Saito; Haruhiko Date; Izumi Taniguchi; Seiji Hokimoto; Nobuyasu Yamamoto; Shinichi Nakamura; Fumiyuki Ishibashi; Katsuo Noda; Syuichi Oshima; Hirofumi Yasue
This study examined the fate of target sites that escaped high-grade restenosis (> or = 70% diameter narrowing) after percutaneous transluminal coronary angioplasty. Although favorable long-term prognosis after successful percutaneous transluminal coronary angioplasty is well documented, little is known about the stability of target sites. Long-term follow-up (mean 6.5 years, range 1.0 to 12.0) was performed in 693 patients with 948 narrowings (stenosis <70% in diameter at follow-up coronary angiography). Among them, 249 patients (36%) with 303 target sites received late follow-up coronary angiography. The relation of target sites to the culprit lesions for coronary events or newly developed angina was angiographically reviewed and progression/regression was also examined, focusing on the target sites. Regression was observed in 16 of 255 target sites in subjects with <50% stenosis and in 21 of 48 sites in the group with midgrade stenosis of 50% to 69% luminal narrowing (16 of 255, 6.3% vs 21 of 48, 43.8%, p <0.001). Progression was observed in 33 and 4 sites (33 of 255, 12.9% vs 4 of 48, 8.3%; p = NS) in each group, respectively. The rest remained within the same range of stenosis. Culprit lesions for 2 acute myocardial infarctions, 7 unstable anginas, and 17 newly developed anginas were related to the original target sites. Three lesions developed in the midgrade stenosis group. Those 26 lesions were a component of 8.6% of 303 angiographically confirmed sites and 2.7% of total target sites. Target sites that escape high-grade restenosis frequently regress and become stable plaques and rarely trigger coronary events.
Journal of Cardiology | 2015
Kenichi Tsujita; Seigo Sugiyama; Hitoshi Sumida; Hideki Shimomura; Takuro Yamashita; Kenshi Yamanaga; Naohiro Komura; Kenji Sakamoto; Takamichi Ono; Hideki Oka; Koichi Nakao; Sunao Nakamura; Masaharu Ishihara; Kunihiko Matsui; Naritsugu Sakaino; Natsuki Nakamura; Nobuyasu Yamamoto; Shunichi Koide; Toshiyuki Matsumura; Kazuteru Fujimoto; Ryusuke Tsunoda; Yasuhiro Morikami; Koushi Matsuyama; Shuichi Oshima; Koichi Kaikita; Seiji Hokimoto; Hisao Ogawa
BACKGROUND Although the positive association between achieved low-density lipoprotein cholesterol (LDL-C) level and the risk of coronary artery disease (CAD) has been confirmed by randomized studies with statins, many patients remain at high residual risk of events suggesting the necessity of novel pharmacologic strategies. The combination of ezetimibe/statin produces greater reductions in LDL-C compared to statin monotherapy. PURPOSE The Plaque REgression with Cholesterol absorption Inhibitor or Synthesis inhibitor Evaluated by IntraVascular UltraSound (PRECISE-IVUS) trial was aimed at evaluating the effects of ezetimibe addition to atorvastatin, compared with atorvastatin monotherapy, on coronary plaque regression and change in lipid profile in patients with CAD. METHODS The study is a prospective, randomized, controlled, multicenter study. The eligible patients undergoing IVUS-guided percutaneous coronary intervention will be randomly assigned to receive either atorvastatin alone or atorvastatin plus ezetimibe (10 mg) daily using a web-based randomization software. The dosage of atorvastatin will be increased by titration within the usual dose range with a treatment goal of lowering LDL-C below 70 mg/dL based on consecutive measures of LDL-C at follow-up visits. IVUS will be performed at baseline and 9-12 months follow-up time point at participating cardiovascular centers. The primary endpoint will be the nominal change in percent coronary atheroma volume measured by volumetric IVUS analysis. CONCLUSION PRECISE-IVUS will assess whether the efficacy of combination of ezetimibe/atorvastatin is noninferior to atorvastatin monotherapy for coronary plaque reduction, and will translate into increased clinical benefit of dual lipid-lowering strategy in a Japanese population.
European Journal of Preventive Cardiology | 2016
Kenichi Tsujita; Kenshi Yamanaga; Naohiro Komura; Kenji Sakamoto; Seigo Sugiyama; Hitoshi Sumida; Hideki Shimomura; Takuro Yamashita; Hideki Oka; Koichi Nakao; Sunao Nakamura; Masaharu Ishihara; Kunihiko Matsui; Naritsugu Sakaino; Natsuki Nakamura; Nobuyasu Yamamoto; Shunichi Koide; Toshiyuki Matsumura; Kazuteru Fujimoto; Ryusuke Tsunoda; Yasuhiro Morikami; Koushi Matsuyama; Shuichi Oshima; Koichi Kaikita; Seiji Hokimoto; Hisao Ogawa
Background The IMPROVE-IT trial showed that the clinical benefit of statin/ezetimibe combination appeared to be pronounced in patients with prior statin therapy. We hypothesized that the antiatherosclerotic effect of atorvastatin/ezetimibe combination was pronounced in patients with statin pretreatment. Methods In the prospective, randomized, controlled, multicenter PRECISE-IVUS trial, 246 patients undergoing intravascular ultrasound-guided percutaneous coronary intervention were randomized to atorvastatin/ezetimibe combination or atorvastatin alone. The dosage of atorvastatin was uptitrated with a treatment goal of lowering low-density lipoprotein cholesterol to below 70 mg/dl in both groups. Serial volumetric intravascular ultrasound was performed at baseline and 9–12 month follow-up to quantify the coronary plaque response in 202 patients. We compared the intravascular ultrasound endpoints in all subjects, stratified by the presence or absence of statin pretreatment. Results The baseline low-density lipoprotein cholesterol level (100.7 ± 23.1 mg/dl vs. 116.4 ± 25.9 mg/dl, p < 0.001) and lathosterol (55 (38 to 87)) µg/100 mg total cholesterol vs. 97 (57 to 149) µg/100 mg total cholesterol, p < 0.001) was significantly lower, and campesterol/lathosterol ratio (3.9 (2.4 to 7.4) vs. 2.6 (1.5 to 4.1), p < 0.001) was significantly increased in patients with statin pretreatment. Contrary to the patients without statin pretreatment (−1.3 (−3.1 to −0.1)% vs. −0.9 (−2.3 to 0.9)%, p = 0.12), the atorvastatin/ezetimibe combination showed a significantly stronger reduction in delta percent atheroma volume, compared with atorvastatin alone, in patients with statin pretreatment (−1.8 (−3.6 to −0.3)% vs. −0.1 (−1.6 to 0.8)%, p = 0.002). Conclusion Compensatory increase in cholesterol absorption observed in statin-treated patients might attenuate the inhibitory effects of statins on coronary plaque progression. A low-dose statin/ezetimibe combination might be a promising option in statin-hyporesponder.
International Journal of Cardiology | 2014
Tomonori Akasaka; Seiji Hokimoto; Shuichi Oshima; Koichi Nakao; Kazuteru Fujimoto; Yuji Miyao; Hideki Shimomura; Ryusuke Tsunoda; Toyoki Hirose; Ichiro Kajiwara; Toshiyuki Matsumura; Natsuki Nakamura; Nobuyasu Yamamoto; Shunichi Koide; Hideki Oka; Yasuhiro Morikami; Naritsugu Sakaino; Koichi Kaikita; Sunao Nakamura; Kunihiko Matsui; Hisao Ogawa
Clinical outcomes of percutaneous coronary intervention (PCI) at hospital with or without onsite cardiac surgery backup Tomonori Akasaka , Seiji Hokimoto ⁎, Shuichi Oshima , Koichi Nakao , Kazuteru Fujimoto , Yuji Miyao , Hideki Shimomura , Ryusuke Tsunoda , Toyoki Hirose , Ichiro Kajiwara , Toshiyuki Matsumura , Natsuki Nakamura , Nobuyasu Yamamoto , Shunichi Koide , Hideki Oka , Yasuhiro Morikami , Naritsugu Sakaino , Koichi Kaikita , Sunao Nakamura , Kunihiko Matsui , Hisao Ogawa , on behalf of, Kumamoto Intervention Conference Study (KICS) Investigators
Journal of Cardiology | 2017
Tomonori Akasaka; Seiji Hokimoto; Daisuke Sueta; Noriaki Tabata; Shuichi Oshima; Koichi Nakao; Kazuteru Fujimoto; Yuji Miyao; Hideki Shimomura; Ryusuke Tsunoda; Toyoki Hirose; Ichiro Kajiwara; Toshiyuki Matsumura; Natsuki Nakamura; Nobuyasu Yamamoto; Shunichi Koide; Shinichi Nakamura; Yasuhiro Morikami; Naritsugu Sakaino; Koichi Kaikita; Sunao Nakamura; Kunihiko Matsui; Hisao Ogawa
BACKGROUND Based on the 2011 American College of Cardiology/American Heart Association percutaneous coronary intervention (PCI) guideline, it is recommended that PCI should be performed at hospital with onsite cardiac surgery. But, data suggest that there is no significant difference in clinical outcomes following primary or elective PCI between the two groups. We examined the impact of with or without onsite cardiac surgery on clinical outcomes following PCI for acute coronary syndrome (ACS). METHODS AND RESULTS From August 2008 to March 2011, subjects (n=3241) were enrolled from the Kumamoto Intervention Conference Study (KICS). Patients were assigned to two groups treated in hospitals with (n=2764) or without (n=477) onsite cardiac surgery. Clinical events were followed up for 12 months. Primary endpoint was in-hospital death, cardiovascular death, myocardial infarction, and stroke. And we monitored in-hospital events, non-cardiovascular deaths, bleeding complications, revascularizations, and emergent coronary artery bypass grafting (CABG). There was no overall significant difference in primary endpoint between hospitals with and without onsite cardiac surgery [ACS, 7.6% vs. 8.0%, p=0.737; ST-segment elevation myocardial infarction (STEMI), 10.4% vs. 7.5%, p=0.200]. There was also no significant difference when events in primary endpoint were considered separately. In other events, revascularization was more frequently seen in hospitals with onsite surgery (ACS, 20.0% vs. 13.0%, p<0.001; STEMI, 21.9% vs. 14.5%, p=0.009). We performed propensity score matching analysis to correct for the disparate patient numbers between the two groups, and there was also no significant difference for primary endpoint (ACS, 8.6% vs. 7.5%, p=0.547; STEMI, 11.2% vs. 7.5%, p=0.210). CONCLUSIONS There is no significant difference in clinical outcomes following PCI for ACS between hospitals with and without onsite cardiac surgery backup in Japan.