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Dive into the research topics where Koyu Sakai is active.

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Featured researches published by Koyu Sakai.


Circulation | 2002

Long-Term Clinical and Angiographic Follow-Up After Coronary Stent Placement in Native Coronary Arteries

Takeshi Kimura; Satoshi Shizuta; Keita Odashiro; Yoshinori Yoshida; Koyu Sakai; Kazuaki Kaitani; Katsumi Inoue; Yoshihisa Nakagawa; Hiroyoshi Yokoi; Masashi Iwabuchi; Naoya Hamasaki; Hideyuki Nosaka; Masakiyo Nobuyoshi

Background—Although coronary stents have been proved effective in reducing clinical cardiac events for up to 3 to 5 years, longer term clinical and angiographic outcomes have not yet been fully clarified. Methods and Results—To evaluate longer term (7 to 11 years) outcome, clinical and angiographic follow-up information was analyzed in 405 patients with successful stenting in native coronary arteries. Primary or secondary stabilization, which was defined as freedom from death, coronary artery bypass grafting, and target lesion-percutaneous coronary intervention (TL-PCI) during the 14 months after the initial procedure or after the last TL-PCI, was achieved in 373 patients (92%) overall. Only 7 patients (1.7%) underwent TL-PCI more than twice. After the initial 14-month period, freedom from TL-PCI reached a plateau at 84.9% to 80.7% over 1 to 8 years. However, quantitative angiographic analysis in 179 lesions revealed a triphasic luminal response characterized by an early restenosis phase until 6 months, an intermediate-term regression phase from 6 months to 3 years, and a late renarrowing phase beyond 4 years. Minimal luminal diameter in 131 patients with complete serial data were 2.62±0.4 mm immediately after stenting, 2.0±0.49 mm at 6 months, 2.19±0.49 mm at 3 years, and 1.85±0.56 mm beyond 4 years (P <0.0001). Conclusions—The efficacy and safety of coronary stenting seemed to be clinically sustained at 7 to 11 years of follow-up. However, late luminal renarrowing beyond 4 years was common, which demonstrates the need for further follow-up.


Cardiovascular Pathology | 2004

Pathological analyses of long-term intracoronary Palmaz-Schatz stenting; Is its efficacy permanent?

Katsumi Inoue; Kenji Ando; Shinichi Shirai; Kei Nishiyama; Michio Nakanishi; Takashi Yamada; Koyu Sakai; Yoshihisa Nakagawa; Naoya Hamasaki; Takeshi Kimura; Masakiyo Nobuyoshi; Tadaomi Alfonso Miyamoto

BACKGROUND Angiographic regression of luminal narrowing occurs 6 months to 3 years poststenting. However, after 4 years lesions progressed gradually and late restenosis was observed in 28% of 179 Palmaz-Schatz-stented lesions during the past 10 years. Elucidating its pathogenesis is pivotal to developing preventive strategies. METHODS AND RESULTS Histopathological and immunohistochemical studies were performed in 19 stented coronary arteries obtained from 19 patients autopsied after noncardiac death 2-7 years poststenting. The quality/severity of chronic inflammatory cells (T lymphocytes, macrophages and multinucleated giant cells) infiltration around the stent struts that is observed even in the absence of restenosis depended on the time elapsed from stenting: a) 2 years postprocedure, in spite of angiographic regression during the first year and pathologically expressed as maturation of the neointimal scar, there was chronic inflammatory response evidence: neovascularization and lymphocyte infiltration, b) > or = 3 years: the neointimal smooth muscle cells were sparse with abundant proliferation of collagen fibers. Presence of slight helper/inducer T lymphocytes and mild macrophage infiltration around the stent struts was evident immunohistochemically, c) > or = 4 years: prominent infiltration by lipid-laden macrophages with strong collagen-degrading matrix metalloproteinase immunoreactivity was observed around the struts. In two of these arteries, the surface contacting the stent was focally disrupted and covered by nonocclusive mural thrombi. CONCLUSIONS Stainless steel stents evoke a remarkable foreign-body inflammatory reaction to the metal. These persistent peri-strut chronic inflammatory cells may accelerate new indolent atherosclerotic changes and consequent plaque vulnerability.


Circulation-cardiovascular Interventions | 2012

Incidence and Clinical Impact of Stent Fracture After Everolimus-Eluting Stent Implantation

Shoichi Kuramitsu; Masashi Iwabuchi; Takuya Haraguchi; Takenori Domei; Ayumu Nagae; Makoto Hyodo; Kyohei Yamaji; Yoshimitsu Soga; Takeshi Arita; Shinichi Shirai; Katsuhiro Kondo; Kenji Ando; Koyu Sakai; Masahiko Goya; Yoshitaka Takabatake; Shinjo Sonoda; Hiroyoshi Yokoi; Fumitoshi Toyota; Hideyuki Nosaka; Masakiyo Nobuyoshi

Background—Stent fracture (SF) after drug-eluting stent implantation has recently become an important concern because of its potential association with in-stent restenosis and stent thrombosis. However, the incidence and clinical impact of SF after everolimus-eluting stent implantation remain unclear. Methods and Results—A total of 1035 patients with 1339 lesions undergoing everolimus-eluting stent implantation and follow-up angiography 6 to 9 months after index procedure were analyzed. SF was defined as complete or partial separation of the stent, as assessed by plain fluoroscopy or intravascular ultrasound during follow-up. We assessed the rates of SF and major adverse cardiac events, defined as cardiac death, myocardial infarction, stent thrombosis, and clinically driven target lesion revascularization within 9 months. SF was observed in 39 of 1339 lesions (2.9%) and in 39 of 1035 patients (3.8%). Ostial stent location and lesions with hinge motion, tortuosity, or calcification were independent predictors of SF. The rate of myocardial infarction and target lesion revascularization were significantly higher in the SF group than in the non-SF group (5.1% versus 0.4%; P=0.018 and 25.6% versus 2.0%; P<0.001, respectively). Stent thrombosis was more frequently observed in the SF group than in the non-SF group (5.1% versus 0.4%; P=0.018). Major adverse cardiac events within 9 months were significantly higher in the SF group than in the non-SF group (25.6% versus 2.3%; P<0.001). Conclusions—SF after everolimus-eluting stent implantation occurs in 2.9% of lesions and is associated with higher rate of major adverse cardiac events, driven by higher target lesion revascularization and stent thrombosis.


Circulation-cardiovascular Interventions | 2012

Bare Metal Stent Thrombosis and In-Stent Neoatherosclerosis

Kyohei Yamaji; Katsumi Inoue; Takuya Nakahashi; Masahiko Noguchi; Takenori Domei; Makoto Hyodo; Yoshimitsu Soga; Shinichi Shirai; Kenji Ando; Katsuhiro Kondo; Koyu Sakai; Masashi Iwabuchi; Hiroyoshi Yokoi; Hideyuki Nosaka; Masakiyo Nobuyoshi; Takeshi Kimura

Background— Very late stent thrombosis (VLST) was reported to occur even in patients with bare metal stent (BMS) implantation, although the annual incidence of VLST after BMS was much lower than that after drug-eluting stent implantation. Pathophysiologic mechanisms of VLST after BMS implantation remain largely unknown. Methods and Results— From September 2002 to February 2010, we identified 102 patients with definite stent thrombosis (ST) of BMS and 42 control patients with acute coronary syndrome (ACS) unrelated to ST who underwent thrombus aspiration with histopathologic evaluation. There were 40 patients with early ST (EST, within 30 days), 20 patients with late ST (LST, between 31–365 days), and 42 patients with VLST (>1 year). Evidence for fragments of atherosclerotic plaques, such as foamy macrophages, cholesterol crystals, and thin fibrous cap, was more commonly seen in patients with EST (23%) and VLST (31%), whereas these findings were rarely observed in patients with LST (10%). Atherosclerotic fragments were predominantly seen in patients who had EST within 7 days or VLST beyond 3 years. The aspirated thrombi harvested from patients with ST and those with ACS were histologically indistinguishable from each other. Eosinophils were very rarely observed. Plasma level of total cholesterol and triglyceride were significantly higher in VLST cases with atherosclerotic fragments as compared with those without. Conclusions— Fragments of atherosclerotic plaque were highly prevalent in patients with VLST beyond 3 years. Disruption of in-stent neoatherosclerosis could play an important role in the pathogenesis of VLST of BMS occurring beyond 3 years after implantation.


Jacc-cardiovascular Interventions | 2010

Impact of multiple and long sirolimus-eluting stent implantation on 3-year clinical outcomes in the j-Cypher Registry.

Shinichi Shirai; Takeshi Kimura; Masakiyo Nobuyoshi; Takeshi Morimoto; Kenji Ando; Yoshimitsu Soga; Kyohei Yamaji; Katsuhiro Kondo; Koyu Sakai; Takeshi Arita; Masahiko Goya; Masashi Iwabuchi; Hiroyoshi Yokoi; Hideyuki Nosaka; Kazuaki Mitsudo; j-Cypher Registry Investigators

OBJECTIVES Our aim was to study the relationships between total stent length (TSL) and long-term clinical outcomes after sirolimus-eluting stent (SES) implantation. BACKGROUND SES compared with bare-metal stent use for long lesion treatment is associated with reduced restenosis rates. METHODS Three-year follow-up data were available for 10,773 patients (14,651 lesions) that had been treated with only SES (Cypher, Cordis Corp., Warren, New Jersey) in the j-Cypher registry. Patients and lesions were divided into quartile groups: TSL per patient (Q1: 8 to 23 mm, Q2: 24 to 36 mm, Q3: 37 to 54 mm, Q4: 55 to 293 mm), and TSL per lesion (QA: 8 to 18 mm, QB: 19 to 23 mm, QC: 24 to 33 mm, QD: 34 to 150 mm). RESULTS In per-lesion data, longer TSL increased target lesion revascularization (TLR) rates but did not increase stent thrombosis rates (p = 0.2324). In per-patient data, the incidences of TLR remarkably increased with increasing TSL. Incidence of composite of death and myocardial infarction also increased with increasing TSL; however, after adjustment for baseline differences, there was no statistical significance. Definite stent thrombosis rate in group Q4 was significantly higher than in other groups, both unadjusted (hazard ratio: 1.770, p = 0.0081) and adjusted (hazard ratio: 1.727, p = 0.0122) for baseline differences. CONCLUSIONS TSL per lesion and patient had significantly impacts on TLR rates. Longer TSL per patient was associated with increased incidence of stent thrombosis through 3 years.


Catheterization and Cardiovascular Interventions | 2012

Primary percutaneous coronary intervention for acute myocardial infarction in the elderly aged ≥75 years†

Koyu Sakai; Shinya Nagayama; Kasumi Ihara; Kenji Ando; Shinichi Shirai; Katsuhiro Kondo; Hiroyoshi Yokoi; Masashi Iwabuchi; Hideyuki Nosaka; Masakiyo Nobuyoshi

Objectives: We aimed to see whether primary percutaneous coronary intervention (PCI) benefits for ST‐segment elevation myocardial infarction (STEMI) in the aged could be validated. Background: Primary PCI benefits in elderly patients with STEMI remain uncertain. Methods: We reviewed 947 consecutive patients treated with primary PCI for STEMI: 331 were aged ≥75 years (older) and 616 <75 years (younger). Results: The older group had higher percentage of renal insufficiency (7.9% vs. 3.1%, P = 0.0010), prior stroke (9.4% vs. 3.9%, P = 0.0006), 30‐day mortality rate (7.6% vs. 3.9%, P = 0.015), and cardiac mortality rate (6.6% vs. 3.7%, P = 0.045). Successful reperfusion rates were similarly high in both groups (90.0% and 92.7%, P = 0.16), despite the higher proportion of patients with door‐to‐balloon time >90 min (15% vs. 8.4%, P = 0.0016) in older patients. Successful compared with unsuccessful PCI significantly decreased 30‐day mortality rates in the older group (6.0% vs. 21%, P = 0.0018) and in the younger group (2.8% vs. 18%, P < 0.0001). When reperfusion was successful, cardiac mortality rate in older patients was not significantly greater than in younger patients (5.4% vs. 2.8%, P = 0.057). By multivariate analysis, unsuccessful reperfusion independently predicted 30‐day mortality (odds ratio, 4.04; 95% confidence interval, 1.79–9.12; P = 0.0008), whereas age ≥75 years (odds ratio, 1.00; 95% confidence interval, 0.41–2.41; P = 0.99) and door‐to‐balloon time >90 min (odds ratio, 1.78; 95% confidence interval, 0.76–4.20; P = 0.19) did not. Conclusions: Pre‐existing comorbidities characterize older patients developing STEMI. Aggressive PCI in older patients improves prognosis, and short door‐to‐balloon time is an important parameter conditioning the prognosis.


American Journal of Cardiology | 2002

Comparison of results of coronary angioplasty for acute myocardial infarction in patients ≥75 years of age versus patients <75 years of age

Koyu Sakai; Yoshihisa Nakagawa; Takeshi Kimura; Takahiro Doi; Hiroyoshi Yokoi; Masashi Iwabuchi; Naoya Hamasaki; Katsumi Inoue; Hideyuki Nosaka; Masakiyo Nobuyoshi

We reviewed 1,063 consecutive patients treated with direct coronary angioplasty for acute myocardial infarction (AMI): 261 were > or =75 and 802 were <75 years of age. Compared with the younger group, the older group had a higher percentage of women (48% vs 22%, p <0.0001), multivessel coronary disease (50% vs 39%, p <0.01), overall in-hospital mortality (8.4% vs 3.7%, p <0.01), cardiac mortality rate (6.1% vs 3.1%, p <0.05), and noncardiac mortality rate (2.3% vs 0.6%, p <0.05). Successful reperfusion was achieved in both groups at a similarly high rate (93% and 95%, p = NS). Hospital mortality was similar whether reperfusion was successful or failed. Successful compared with unsuccessful angioplasty decreased mortality rates in the older (6.6% vs 33%, p <0.0001) and younger (3.0% vs 18%, p <0.0001) groups. When reperfusion was successful, the cardiac mortality rate in older patients was not significantly higher than in younger patients: 4.1% vs 2.4%, p = NS.


European Journal of Preventive Cardiology | 2010

Safety of early exercise training after elective coronary stenting in patients with stable coronary artery disease

Yoshimitsu Soga; Hiroyoshi Yokoi; Kenji Ando; Shinichi Shirai; Koyu Sakai; Katsuhiro Kondo; Masahiko Goya; Masashi Iwabuchi; Masakiyo Nobuyoshi

Background Early exercise after coronary stenting is considered to have a risk of stent thrombosis (ST). We investigate the safety of submaximal exercise training based on the Borg scale from the next day after coronary stenting. Methods We enrolled 2351 patients who underwent successful coronary stenting. They were divided into early exercise training (EET) group (n = 865) and control group (n = 1486). Submaximal exercise training based on the Borg scale was performed on the next day after coronary stenting and same degree exercise was continued more than two times a week after discharge. Primary endpoint was the incidence of ST. Secondary endpoint was major adverse cardiovascular event (death, myocardial infarction, and stroke), incidence of postoperative complications, and rate of exercise continuation. Results Exercise training was performed in 800 (92.5%) patients. No serious complication developed during and after exercise. Clinical follow-up data were obtained in 99% patients. At 30 days, there was no significant difference in the incidence of ST (0.58 vs. 0.47%, P = 0.73), major adverse cardiovascular event (1.4 vs. 1.3%, P = 0.72), and complication rate (6.9 vs. 7.3%, P =0.72). No exercise-related ST was found in either group. The rate of exercise continuation was significantly higher in the EET group (49.3 vs. 28.3%, P >0.001). Conclusion EET up to submaximal level based on the Borg scale from the day after elective coronary stenting does not increase the incidence of ST or postoperative complications.


Journal of the American Heart Association | 2014

Incidence and Clinical Impact of Stent Fracture After the Nobori Biolimus-Eluting Stent Implantation

Shoichi Kuramitsu; Masashi Iwabuchi; Hiroyoshi Yokoi; Takenori Domei; Shinjo Sonoda; Takashi Hiromasa; Takashi Morinaga; Yohei Kobayashi; Kensuke Ohe; Kaoru Goya; Kyohei Yamaji; Makoto Hyodo; Yoshimitsu Soga; Katsuhiro Kondo; Shinichi Shirai; Kenji Ando; Koyu Sakai; Masakiyo Nobuyoshi

Background Stent fracture (SF) after drug‐eluting stent implantation has become an important concern. The aim of this study was to assess the incidence, predictors, and clinical impact of SF after biolimus‐eluting stent. Methods and Results A total of 1026 patients with 1407 lesions undergoing the Nobori biolimus‐eluting stent implantation and follow‐up angiography within 9 months after index procedure were analyzed. SF was defined as complete or partial separation of the stent, as assessed by using plain fluoroscopy, intravascular ultrasound, or optical coherence tomography during the follow‐up. We assessed the rate of SF and the cumulative incidence of clinically driven target lesion revascularization and definite stent thrombosis within 9 months. SF was observed in 58 (4.1%) of 1407 lesions and 57 (5.5%) of 1026 patients. Lesions with hinge motion (OR 8.90, 95% CI 3.84 to 20.6, P<0.001), tortuosity (OR 4.16, 95% CI 1.75 to 9.88, P=0.001), and overlapping stents (OR 2.41, 95% CI 0.95 to 6.10, P=0.06) were predictors of SF. Cumulative incidence of clinically driven target lesion revascularization within 9 months was numerically higher in the SF group than that in the non‐SF group (12.0% versus 1.0%). Cumulative incidence of definite stent thrombosis within 9 months tended to be higher in the SF group than that in the non‐SF group (1.7% versus 0.5%). Conclusions SF after biolimus‐eluting stent occurs in 4.1% of lesions and appears to be associated with clinically driven target lesion revascularization.


Cardiovascular Diabetology | 2013

Impact of post-challenge hyperglycemia on clinical outcomes in japanese patients with stable angina undergoing percutaneous coronary intervention

Shoichi Kuramitsu; Hiroyoshi Yokoi; Takenori Domei; Akihiro Nomura; Hirotoshi Watanabe; Kyohei Yamaji; Yoshimitsu Soga; Takeshi Arita; Katsuhiro Kondo; Shinichi Shirai; Kenji Ando; Koyu Sakai; Masashi Iwabuchi; Hedeyuki Nosaka; Masakiyo Nobuyoshi

BackgroundPost-challenge hyperglycemia (PH) is well-established as one of risk factors for coronary artery disease. However, it remains unclear whether PH affects clinical outcomes in patients with stable angina undergoing percutaneous coronary intervention (PCI).MethodsA total of 828 patients with stable angina undergoing PCI were retrospectively analyzed. Of these, 452 patients with previously diagnosed diabetes mellitus (DM) or fasting plasma glucose (PG) ≥126 mg/dl and HbA1c ≥6.5% were defined as known DM. The remaining 376 patients were divided into the two groups according to 2-h PG: PH (2-h PG ≥140 mg/dl, n=236) and normal glucose tolerance (NGT, 2-h PG <140 mg/dl, n=140). We assessed the rate of major adverse cardiovascular events (MACE), defined as a composite of cardiovascular death, myocardial infarction, stroke, and clinically-driven revascularization.ResultsDuring the median follow-up of 4.3 years, the MACE rate was significantly higher in the DM and PH groups than the NGT group (39.3% vs. 20.7%, P <0.001; 31.4% vs. 20.7%, P=0.044, respectively). Compared with the NGT group, the cumulative incidence of revascularization was significantly higher in the DM group (35.1% vs. 18.5%, P <0.001) and tended to be higher in the PH group (27.1% vs. 18.5%, P=0.067). In the multivariate analysis, known DM (Hazard ratio [HR]: 2.16, 95% confidence interval (CI): 1.49-3.27, P < 0.001), PH (HR: 1.62, 95% CI: 1.07-2.53, P = 0.023), LDL-C >100 mg/dl (HR: 1.62, 95% CI: 1.26 to 2.10, P < 0.001), and previous stroke (HR: 1.47, 95% CI: 1.03-2.04, P = 0.034) were predictors of MACE.ConclusionPH is associated with future cardiovascular events in patients with stable angina undergoing PCI.

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Masakiyo Nobuyoshi

Memorial Hospital of South Bend

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Hiroyoshi Yokoi

Memorial Hospital of South Bend

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Masashi Iwabuchi

Memorial Hospital of South Bend

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Kenji Ando

Memorial Hospital of South Bend

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Shinichi Shirai

Memorial Hospital of South Bend

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Hideyuki Nosaka

Memorial Hospital of South Bend

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Yoshimitsu Soga

Memorial Hospital of South Bend

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Hitoshi Yasumoto

Memorial Hospital of South Bend

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Katsuhiro Kondo

Memorial Hospital of South Bend

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