Kenichi Sakakura

CBSET, Lexington, Massachusetts, United States

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Publications (117)656.77 Total impact

  • JACC. Cardiovascular Interventions 08/2015; 8(10):1396-8. DOI:10.1016/j.jcin.2015.03.041 · 7.44 Impact Factor
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    ABSTRACT: Compared to transpulmonary pressure gradient (TPPG), diastolic pulmonary vascular pressure gradient (DPG) may be a more sensitive and specific indicator for pulmonary hypertension (PH) due to left heart disease (LHD) with significant pulmonary vascular disease (PVD). The aim of this study was to investigate the incidence and clinical features of PH-LHD with PVD classified by DPG and TPPG. We analyzed 410 patients admitted for symptomatic heart failure (HF) (New York Heart Association ≥2) and who underwent right heart catheterization (RHC) at compensated stage between 2007 and 2012. Patients with PH-LHD were divided into 3 groups according to the value of DPG and TPPG (Non-PVD group: DPG <7mmHg and TPPG ≤12mmHg; TPPG-PVD group: DPG <7mmHg and TPPG >12mmHg; DPG-PVD group: DPG ≥7mmHg). Multivariate Cox regression analysis was applied to investigate whether each PH-LHD category predicts death or HF readmission after adjusting for other variables. PH-LHD was observed in 164 patients (40%) with symptomatic HF. Thirteen patients (3%) were allocated into DPG-PVD group, while 24 patients were allocated into TPPG-PVD group (6%). DPG-PVD group was significantly associated with death or HF readmission compared to non-PVD group (hazard ratio: 3.57; 95% CI: 1.33 to 9.55, p=0.01), while the association between TPPG-PVD group and non-PVD group did not reach statistical significance (hazard ratio: 1.89; 95% CI: 0.77 to 4.64, p=0.17). PH-LHD with PVD classified by DPG was significantly associated with poor long-term clinical outcomes, whereas the association between PH-LHD with PVD classified by TPPG and clinical outcomes did not reach statistical significance. However, further studies are needed, because there was no substantial difference in clinical outcomes between PH-LHD with PVD classified by DPG and PH-LHD with PVD classified by TPPG. Copyright © 2015 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.
    Journal of Cardiology 08/2015; DOI:10.1016/j.jjcc.2015.07.015 · 2.57 Impact Factor
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    ABSTRACT: This study sought to evaluate whether the permanent fluoropolymer-coated Xience Xpedition everolimus-eluting stent (Xience-EES) exhibits lower acute thrombogenicity compared with contemporary drug-eluting stents (DES) with biodegradable polymer coatings in an acute swine shunt model. Previous pre-clinical and clinical experience suggests that several factors may influence the predisposition for acute thrombus formation of polymer-coated DES, including stent design and the polymer coating technology. It remains unclear whether relevant differences exist with respect to acute thrombogenicity, particularly between current commercial stent designs using permanent polymers and those using biodegradable polymers. An ex vivo carotid to jugular arteriovenous porcine shunt model involving a test circuit of 3 in-line stents, was used to test acute thrombogenicity, where Xience-EES (n = 24) was compared with 4 CE-marked DES with biodegradable polymer coatings (BioMatrix Flex, Synergy, Nobori, and Orsiro [n = 6 each]). After 1 h of circulation, platelet aggregation in whole mount stents was evaluated by confocal microscopy with immunofluorescent staining against dual platelet markers (CD61/CD42b) along with scanning electron microscopy. Xience-EES showed the least percentage of thrombus-occupied area as compared with the biodegradable polymer-coated DES, with a significant difference compared with BioMatrix Flex and Synergy (mean differences: [BioMatrix Flex: 15.54, 95% confidence interval [CI]: 11.34 to 19.75, p < 0.001; Synergy: 8.64, 95% CI: 4.43 to 12.84, p < 0.001; Nobori: 4.22, 95% CI: -0.06 to 8.49, p = 0.055; Orsiro: 2.95, 95% CI: -1.26 to 7.15, p = 0.286). The number of cell nuclei on strut surfaces was also the least in Xience-EES, with a significant difference relative to BioMatrix Flex, Nobori, and Orsiro (mean ratios: BioMatrix Flex: 4.73, 95% CI: 2.46 to 9.08, p < 0.001; Synergy: 1.44, 95% CI: 0.75 to 2.76, p = 0.51; Nobori: 5.97, 95% CI: 3.11 to 11.44, p < 0.001; Orsiro: 5.16, 95% CI: 2.69 to 9.91, p < 0.001). Xience-EES's overall design confers acute thromboresistance relative to contemporary DES with biodegradable coatings, with less platelet aggregation versus BioMatrix Flex and Synergy, and less inflammatory cell attachment versus BioMatrix Flex, Nobori, and Orsiro, in an ex vivo swine shunt model, which lends support to reported clinical findings of lower early stent thrombosis. Copyright © 2015 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.
    JACC. Cardiovascular Interventions 08/2015; 8(9):1248-60. DOI:10.1016/j.jcin.2015.03.029 · 7.44 Impact Factor
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    ABSTRACT: Clinical outcomes of implantation of the newer-generation drug-eluting stent (DES) following rotational atherectomy for heavily calcified lesions remain unclear in the real-world setting.Methods and Results:We enrolled 252 consecutive patients (273 lesions) treated with newer-generation DES following rotational atherectomy. The primary endpoint was the cumulative 2-year incidence of major adverse cardiovascular events (MACE), defined as cardiac death, myocardial infarction, clinically-driven target lesion revascularization, and definite stent thrombosis. Complete clinical follow-up information at 2-year was obtained for all patients. The mean age was 73.2±9.0 years and 155 patients (61.5%) were male. Cumulative 2-year incidence of MACE (cardiac death, myocardial infarction, clinically-driven target lesion revascularization and definite stent thrombosis) was 20.3% (7.0%, 2.1%, 18.1% and 2.1%, respectively). Predictors of MACE were presenting with acute coronary syndrome (hazard ratio [HR]: 3.80, 95% confidence interval [CI]: 1.29-11.2, P=0.02), hemodialysis (HR: 1.93, 95% CI: 1.04-3.56, P=0.04) and previous coronary artery bypass graft (HR: 2.26, 95% CI: 1.02-5.00, P=0.045). PCI for calcified lesions requiring rotational atherectomy is still challenging even in the era of newer-generation DES.
    Circulation Journal 06/2015; DOI:10.1253/circj.CJ-15-0233 · 3.69 Impact Factor
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    ABSTRACT: Diabetes mellitus and impaired glucose tolerance are well-known risk factors for coronary artery disease (CAD) and adverse clinical events after percutaneous coronary intervention (PCI). Postprandial hyperglycemia is an important risk factor for CAD and serum 1,5-anhydroglucitol (1,5-AG) reflects postprandial hyperglycemia more robustly than hemoglobin (Hb)A1c. We aimed to clarify the relationship between serum 1,5-AG level and adverse clinical events after PCI. We enrolled 141 patients after PCI with follow-up coronary angiography. We evaluated associations between glycemic biomarkers including HbA1c and 1,5-AG and cardiovascular events during follow-up. Median serum 1,5-AG level was significantly lower in patients with any coronary revascularization and target lesion revascularization (TLR) [13.4 µg/ml (first quartile, third quartile 9.80, 18.3) vs. 18.7 (12.8, 24.2), p = 0.005; 13.4 µg/ml (10.2, 16.4) vs. 18.7 (12.9, 24.2), p = 0.001, respectively]. Multivariate logistic analysis showed lower 1,5-AG was independently associated with any coronary revascularization and TLR (odds ratio 0.93, 95 % confidence interval 0.86-0.99, p = 0.04; 0.90, 0.81-0.99, p = 0.044, respectively), whereas higher HbA1c was not. Postprandial hyperglycemia and lower 1,5-AG are important risk factors for adverse clinical events after PCI.
    Heart and Vessels 04/2015; DOI:10.1007/s00380-015-0682-0 · 2.11 Impact Factor
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    ABSTRACT: Acute aortic dissection (AAD) is a life-threatening cardiovascular disease with high mortality. Hypertension is a well known risk factor of AAD. There have been previous reports about the association between circadian variation of blood pressure (BP) and cardiovascular events. However, little is known about the association between the onset-time of AAD and circadian variation of BP. The purpose of this study was to clarify the characteristics of circadian variation of BP in AAD and its relation to the onset-time of this disease. This study included type B spontaneous AAD patients who were referred to our institution and treated conservatively between January 2008 and June 2013. Patients with type A AAD, secondary to trauma, and type B AAD which preceded surgical intervention were excluded. Data were retrospectively collected from the hospital medical records. Sixty-eight patients with type B AAD were enrolled. The distribution of the circadian pattern in the study patients was as follows: extreme-dipper, 0% (none); dipper, 20.6% (n = 14); nondipper, 50% (n = 34); riser, 29.4% (n = 20). Non-dipper and riser patterns were more frequently observed compared with other population studies reported previously. Moreover, no patient in the dipper group had night-time onset while 31.5% of the patients in the absence of nocturnal BP fall group (non-dipper and riser) did (P = 0.01). Absence of a nocturnal BP fall was frequently seen in AAD patients. Absence of a nocturnal BP fall may be a risk factor of AAD. Circadian variation of BP may also affect the onset-time of type B AAD.
    International Heart Journal 04/2015; 56(3). DOI:10.1536/ihj.14-328 · 1.13 Impact Factor
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    ABSTRACT: Thrombus aspiration is currently the standard strategy for primary PCI. Thrombus can be aspirated via aspiration catheters, restoring coronary blood flow. However, there are a limited number of reports regarding thrombus aspiration toward tumor embolized occlusion. We present a case of 90-year-old male with AMI caused by the metastatic tumor embolism. Emergent coronary angiography revealed total occlusion in three epicardial vessels. Histopathological examination of the aspirated specimen revealed the mixture of thrombus and metastatic tumor cells. Thrombus aspiration was partially effective for restoring coronary blood flow; however, it was very helpful for the final diagnosis of tumor embolism.
    Cardiovascular Intervention and Therapeutics 02/2015; DOI:10.1007/s12928-015-0323-7
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    Austin Roth · Leslie Coleman · Kenichi Sakakura · Elena Ladich · Renu Virmani
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    ABSTRACT: An intra-luminal ultrasound catheter system (ReCor Medical's Paradise System) has been developed to provide circumferential denervation of the renal sympathetic nerves, while preserving the renal arterial intimal and medial layers, in order to treat hypertension. The Paradise System features a cylindrical non-focused ultrasound transducer centered within a balloon that circulates cooling fluid and that outputs a uniform circumferential energy pattern designed to ablate tissues located 1-6 mm from the arterial wall and protect tissues within 1 mm. RF power and cooling flow rate are controlled by the Paradise Generator which can energize transducers in the 8.5-9.5 MHz frequency range. Computer simulations and tissue-mimicking phantom models were used to develop the proper power, cooling flow rate and sonication duration settings to provide consistent tissue ablation for renal arteries ranging from 5-8 mm in diameter. The modulation of these three parameters allows for control over the near-field (border of lesion closest to arterial wall) and far-field (border of lesion farthest from arterial wall, consisting of the adventitial and peri-adventitial spaces) depths of the tissue lesion formed by the absorption of ultrasonic energy and conduction of heat. Porcine studies have confirmed the safety (protected intimal and medial layers) and effectiveness (ablation of 1-6 mm region) of the system and provided near-field and far-field depth data to correlate with bench and computer simulation models. The safety and effectiveness of the Paradise System, developed through computer model, bench and in vivo studies, has been demonstrated in human clinical studies.
    SPIE Photonics West; 02/2015
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    ABSTRACT: The pathology of radiofrequency-derived sympathetic renal denervation has not been studied over time and may provide important understanding of the mechanisms resulting in sustained blood pressure reduction. The purpose of this study was to investigate chronological changes after radiofrequency-renal denervation in the swine model. A total of 49 renal arteries from 28 animals with 4 different time points (7, 30, 60, and 180 days) were examined. Semiquantitative histological assessment of arteries and associated tissue was performed to characterize the chronological progression of the radiofrequency lesions. Arterial medial circumferential injury (%) was greatest at 7 days (38±13%), followed by 30 days (31±6%) and 60 days (31±15%), and least at 180 days (21±12%) (P=0.046). Nerve injury score was significantly greater (P<0.001) at 7 days (3.9±0.4) compared with 30 days (2.5±0.5), 60 days (2.6±0.5), and 180 days (1.9±0.9). Tyrosine hydroxylase score, which assesses functional nerve damage, was significantly less after 7 (1±1) and 30 days (0.7±0.6) compared with 60 (2.7±0.6) and 180 days (2.7±0.6; P=0.01). Focal nerve regeneration at the sites of radiofrequency ablation was observed in 17% of renal arteries at 60 days and 71% of 180 days. Nerve injury after radiofrequency ablation was greatest at 7 days, with maximum functional nerve damage sustained ≤30 days. Focal terminal nerve regeneration was observed only at the sites of ablation as early as 60 days and continued to 180 days. Renal artery and peri-arterial soft tissue injury is greatest in the subacute phase, and least in the chronic phase, suggesting gradual recovery of the renal arterial wall and surrounding tissue. © 2015 American Heart Association, Inc.
    Circulation Cardiovascular Interventions 02/2015; 8(2). DOI:10.1161/CIRCINTERVENTIONS.114.001813 · 6.98 Impact Factor
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    ABSTRACT: The long-term efficacy of radiofrequency ablation of renal autonomic nerves has been proven in nonrandomized studies. However, long-term safety of the renal artery (RA) is of concern. The aim of our study was to determine if cooling during radiofrequency ablation preserved the RA while allowing equivalent nerve damage. A total of 9 swine (18 RAs) were included, and allocated to irrigated radiofrequency (n=6 RAs, temperature setting: 50°C), conventional radiofrequency (n=6 RAs, nonirrigated, temperature setting: 65°C), and high-temperature radiofrequency (n=6 RAs, nonirrigated, temperature setting: 90°C) groups. RAs were harvested at 10 days, serially sectioned from proximal to distal including perirenal tissues and examined after paraffin embedding, and staining with hematoxylin-eosin and Movat pentachrome. RAs and periarterial tissue including nerves were semiquantitatively assessed and scored. A total of 660 histological sections from 18 RAs were histologically examined by light microscopy. Arterial medial injury was significantly less in the irrigated radiofrequency group (depth of medial injury, circumferential involvement, and thinning) than that in the conventional radiofrequency group (P<0.001 for circumference; P=0.003 for thinning). Severe collagen damage such as denatured collagen was also significantly less in the irrigated compared with the conventional radiofrequency group (P<0.001). Nerve damage although not statistically different between the irrigated radiofrequency group and conventional radiofrequency group (P=0.36), there was a trend toward less nerve damage in the irrigated compared with conventional. Compared to conventional radiofrequency, circumferential medial damage in highest-temperature nonirrigated radiofrequency group was significantly greater (P<0.001). Saline irrigation significantly reduces arterial and periarterial tissue damage during radiofrequency ablation, and there is a trend toward less nerve damage. © 2014 American Heart Association, Inc.
    Circulation Cardiovascular Interventions 01/2015; 8(1). DOI:10.1161/CIRCINTERVENTIONS.114.001720 · 6.98 Impact Factor
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    ABSTRACT: The optimal preoperative therapeutic strategy for patients with coronary artery disease (CAD) is an important concern in the era of drug-eluting stents and antiplatelet therapy. However, there are few studies about the impact of prior percutaneous coronary intervention (PCI) on perioperative major adverse cardiac events (MACEs) and bleeding events associated with oral antiplatelet therapy. The aim of this study was to examine the risks and benefits of performing PCI before non-cardiac surgery (NCS) in patients with CAD. We investigated 130 patients who had angiographically significant and stable CAD and underwent NCS after index coronary angiography. We divided the patients into two groups: patients undergoing PCI with coronary stenting (PCI group), and those not undergoing PCI before NCS (no-PCI group), and compared the MACEs and bleeding events within 30 days from NCS between the groups. There were 53 and 77 patients in the PCI and no-PCI groups, respectively. MACEs were observed in 2 patients (3.8%) in the PCI group and 3 patients (3.9%) in the no-PCI group (p=0.97), whereas bleeding events were observed in 10 (18.9%) and 8 patients (10.4%) in the PCI and no-PCI groups, respectively (p=0.17). There were no significant differences between the two groups in terms of MACEs and bleeding events. The rate of MACEs following NCS was not significantly different between the PCI and no-PCI groups, while the rate of bleeding events was higher in the PCI group without reaching statistical significance. This study suggests that patients with stable CAD may be able to safely undergo NCS without revascularization even in the presence of significant coronary artery stenosis. Copyright © 2015 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.
    Journal of Cardiology 01/2015; DOI:10.1016/j.jjcc.2014.12.008 · 2.57 Impact Factor
  • JACC Cardiovascular Imaging 11/2014; 7(11). DOI:10.1016/j.jcmg.2014.08.005 · 6.99 Impact Factor
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    ABSTRACT: Aims: The Paradise Ultrasound Renal Denervation System is a next-generation catheter-based device which was used to investigate whether the target ablation area can be controlled by changing ultrasound energy and duration to optimise nerve injury while preventing damage to the arterial wall. Methods and results: Five ultrasound doses were tested in a thermal gel model. Catheter-based ultrasound denervation was performed in 15 swine (29 renal arteries) to evaluate five different doses in vivo, and animals were euthanised at seven days for histopathologic assessment. In the gel model, the peak temperature was highest in the low power-long duration (LP-LD) dose, followed by the mid-low power-mid duration (MLP-MD) dose and the mid-high power-short duration (MHP-SD) dose, and lowest in the mid power-short duration (MP-SD) dose and the high power-ultra short duration (HP-USD) dose. In the animal study, total ablation area was significantly greater in the LP-LD group, followed by the MLP-MD group, and it was least in the HP-USD, MP-SD and MHP-SD groups (p=0.02). Maximum distance was significantly greater in the LP-LD group, followed by the MLP-MD group, the MHP-SD group, and the HP-USD group, and shortest in the MP-SD group (p=0.007). The short spare distance was not different among the five groups (p=0.38). Renal artery damage was minimal, while preserving significant nerve damage in all groups. Conclusions: The Paradise Ultrasound Renal Denervation System is a controllable system where total ablation area and depth of ablation can be optimised by changing ultrasound power and duration while sparing renal arterial tissue damage but allowing sufficient peri-arterial nerve damage.
    EuroIntervention: journal of EuroPCR in collaboration with the Working Group on Interventional Cardiology of the European Society of Cardiology 10/2014; 10(11). DOI:10.4244/EIJY14M10_14 · 3.76 Impact Factor
  • Journal of Cardiac Failure 10/2014; 20(10):S168. DOI:10.1016/j.cardfail.2014.07.210 · 3.07 Impact Factor
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    ABSTRACT: Transcatheter ablation of renal autonomic nerves is a viable option for the treatment of resistent arterial hypertension; however, structured pre-clinical evaluation with standardization of analytical procedures remains a clear gap in this field. Here we discuss the topics relevant to the pre-clinical model for the evaluation of renal denervation (RDN) devices and report methodologies and criteria toward standardization of the safety and efficacy assessment, including histopathological evaluations of the renal artery, periarterial nerves, and associated periadventitial tissues. The pre-clinical swine renal artery model can be used effectively to assess both the safety and efficacy of RDN technologies. Assessment of the efficacy of RDN modalities primarily focuses on the determination of the depth of penetration of treatment-related injury (e.g., necrosis) of the periarterial tissues and its relationship (i.e., location and distance) and the effect on the associated renal nerves and the correlation thereof with proxy biomarkers including renal norepinephrine concentrations and nerve-specific immunohistochemical stains (e.g., tyrosine hydroxylase). The safety evaluation of RDN technologies involves assessing for adverse effects on tissues local to the site of treatment (i.e., on the arterial wall) as well as tissues at a distance (e.g., soft tissue, veins, arterial branches, skeletal muscle, adrenal gland, ureters). Increasing experience will help to create a standardized means of examining all arterial beds subject to ablative energy and in doing so enable us to proceed to optimize the development and assessment of these emerging technologies.
    JACC Cardiovascular Interventions 09/2014; 7(10). DOI:10.1016/j.jcin.2014.04.024 · 7.44 Impact Factor
  • Journal of the American College of Cardiology 09/2014; 64(11):B129-B130. DOI:10.1016/j.jacc.2014.07.493 · 15.34 Impact Factor
  • Journal of the American College of Cardiology 09/2014; 64(11):B127. DOI:10.1016/j.jacc.2014.07.486 · 15.34 Impact Factor
  • Journal of the American College of Cardiology 09/2014; 64(11):B180-B181. DOI:10.1016/j.jacc.2014.07.683 · 15.34 Impact Factor
  • Journal of the American College of Cardiology 09/2014; 64(11):B127-B128. DOI:10.1016/j.jacc.2014.07.487 · 15.34 Impact Factor
  • Journal of the American College of Cardiology 09/2014; 64(11):B121. DOI:10.1016/j.jacc.2014.07.462 · 15.34 Impact Factor

Publication Stats

388 Citations
656.77 Total Impact Points

Institutions

  • 2015
    • CBSET
      Lexington, Massachusetts, United States
  • 2013–2015
    • CVPath Institute
      GAI, Maryland, United States
  • 2005–2015
    • Jichi Medical University
      • • Division of Cardiovascular Surgery
      • • Department of Medicine
      Totigi, Tochigi, Japan