Masami Ochi

Nippon Medical School, Edo, Tōkyō, Japan

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Publications (107)137.78 Total impact

  • Journal of Arrhythmia 12/2014; 30(6):444-445. DOI:10.1016/j.joa.2013.11.003
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    ABSTRACT: Adult patients with atrial septal defect frequently experience atrial fibrillation. However, the electrophysiologic mechanism has not been directly examined, and the optimal surgical procedure has not been determined. Ten patients undergoing operations for atrial septal defect and atrial fibrillation underwent intraoperative mapping by use of 253 epicardial electrodes. There were 7 men and 3 women, whose average age was 54 ± 11 years. Eight patients had a secundum defect and 2 a primum defect. There were 4 patients with paroxysmal atrial fibrillation and 6 with long-standing persistent atrial fibrillation. A modified biatrial Maze procedure was performed in 6 patients and pulmonary vein isolation with no other left atrial lesions in 4. The reentrant or focal activations driving atrial fibrillation were confined within the right atrium in all patients with paroxysmal atrial fibrillation, whereas multiple focal activations arising from the pulmonary veins or posterior left atrium and reentrant activations in the left atrium were observed in 5 of 6 patients with long-standing persistent atrial fibrillation. In 9 patients, sinus rhythm was restored postoperatively and 8 of those patients have been free of any atrial fibrillation during a follow-up period of 94 ± 45 months. The pattern of the atrial activation during atrial fibrillation correlated with the type of atrial fibrillation and varied from a simple right atrial reentry to complex reentrant and focal activations in the left atrium.
    The Annals of thoracic surgery 08/2013; 96(4):1266-1272. DOI:10.1016/j.athoracsur.2013.05.063 · 3.65 Impact Factor
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    ABSTRACT: Volume-rendering computed tomography (CT) without contrast medium has clearly demonstrated the 3-D mapping of the saphenous vein (SV). Contrastless volume-rendering CT was used to preoperatively evaluate the SV anatomy before coronary artery bypass grafting (CABG). This technique was useful for atypical anatomical variations, such as partial duplication of SV (Case 1) or varicose veins (Case 2). Volume-rendering CT may also help with redo CABG (to determine remaining SV) or during endoscopic SV harvesting with restricted view. Volume-rendering CT is an objective, less time-consuming modality to evaluate the SV preoperatively and may be less invasive in terms of avoiding unnecessary skin incision.
    Interactive Cardiovascular and Thoracic Surgery 01/2013; 16(4). DOI:10.1093/icvts/ivs576 · 1.11 Impact Factor
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    ABSTRACT: "Depolarized arrest", induced by hyperkalemic (moderately increased extracellular potassium) cardioplegia is the gold standard to achieve elective temporary cardiac arrest in cardiac surgery. Hyperkalemic cardioplegic solutions provide good myocardial protection, which is relatively safe and easily and rapidly reversible. However, this technique has detrimental effects associated with ionic imbalance involving sodium and calcium overload of the cardiac cell induced by depolarization of the cell membrane. Hence, the development of an improved cardioplegic solution that enhances myocardial protection would be expected as an alternative to hyperkalemic cardioplegia. In this review, we assess the potential disadvantages of "depolarized arrest" and the suitability and clinical potential of "non-depolarized arrest". "Magnesium cardioplegia" and "esmolol cardioplegia" has been shown to exert superior protection with comparable safety profiles to that of hyperkalemic cardioplegia. These alternative techniques require further examination and investigation to challenge the traditional view that hyperkalemic arrest is best. Endogenous cardioprotective strategies, termed "ischemic preconditioning" and "ischemic postconditioning", may have a role in cardiac surgery to provide additional protection. The elective nature of cardiac surgery, with the known onset of ischemia and reperfusion, lends it to the potential of these strategies. However, the benefit of preconditioning and postconditioning during cardiac surgery is controversial, particularly in the context of cardioplegia. The clinical application of these strategies is unlikely to become routine during cardiac surgery because of the necessity for repeated aortic crossclamping with consequent potential for embolic events, but offers considerable potential especially if "pharmacological" preconditioning and postconditioning could be established.
    Journal of Nippon Medical School 01/2013; 80(5):328-41. DOI:10.1272/jnms.80.328 · 0.59 Impact Factor
  • Yuji Maruyama, Masami Ochi
    01/2013; 19(2):171-178. DOI:10.7793/jcoron.19.016
  • Surgical Science 01/2013; 04(12):543-546. DOI:10.4236/ss.2013.412105
  • Circulation 12/2012; 126(25):3095-6. DOI:10.1161/CIRCULATIONAHA.112.118075 · 14.95 Impact Factor
  • Masami Ochi
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    ABSTRACT: Since its introduction in the early 1970s, coronary artery bypass grafting (CABG) has become an established surgical treatment for coronary artery disease (CAD). Percutaneous coronary intervention (PCI), first clinically applied in 1977, was promoted as an alternative to CABG during the mid-1980s. Along with the nationwide expansion of PCI, the ratio of PCI to CABG has exceeded 6-7:1. The Japanese Circulation Society (JCS) published "Guidelines on elective coronary intervention, including coronary artery bypass grafting (CABG), for ischemic heart disease in 2000" and "Guidelines on the selection of bypass conduits and operative procedures in coronary artery bypass grafting for ischemic heart disease". The society intended to revise these guidelines in 2010 and to issue two new guidelines specific either to PCI or CABG. They also planned to issue joint guidelines for myocardial revascularization and PCI/CABG, which are primary indications for patients with stable CAD, especially with those with more complex left main trunk disease and/or multi-vessel disease. The scientific committee of JCS established the "Council for myocardial revascularization" that consisted of experts including interventional and non-interventional cardiologists, cardiac surgeons and physicians specialized in diabetes or nephrology selected by medical and surgical societies. After over 10 rounds of meetings, the Council prepared primary guidelines for myocardial revascularization to treat stable CAD, PCI/CABG. These guidelines consist of (1) Statements about myocardial revascularization, (2) Interpretation of the statements and (3) Indications for PCI/CABG including a table.
    General Thoracic and Cardiovascular Surgery 12/2012; 61(5). DOI:10.1007/s11748-012-0182-4
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    ABSTRACT: An infected aortic arch aneurysm is a rare but life-threatening condition. Moreover, surgical treatment for patients with severe calcified aorta is challenging and needs a well-planned strategy. We report a patient with an infected aortic arch aneurysm concomitant with severe calcification of the aorta in whom good results were obtained with open stent grafting in combination with a trifurcated graft.
    11/2012; 19(3). DOI:10.5761/
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    ABSTRACT: Double potential mapping using bipolar electrodes that straddle the ablation line should identify the site of incomplete ablation as a conduction gap without constructing the activation maps. Bipolar electrograms were recorded during pacing using 11 custom-made bipolar electrodes straddling the ablation line created by a bipolar radiofrequency ablation device on the lateral right atrium in seven canines. A linear ablation was made with an ablation device, of which one jaw was inserted into the atrium through a purse-string suture. A 3-mm-wide tape was placed on both jaws 10 mm from the tip of the ablation electrode to intentionally create an incomplete ablation lesion. The activation times at each dipole across the ablation line were defined as the times of the maximum positive and negative derivatives of the double potentials, and the site of conduction gap was determined as the site of the earliest activation across the linear ablation. The lateral right atrium was mapped simultaneously with 45 different bipolar electrodes to construct the activation maps and the earliest activation site across the ablation line was determined. The double potential mapping located the conduction gap on a real-time basis without displaying any maps. There was no significant change in the accuracy between the different times after ablation and different pacing cycle lengths. Double potential mapping locates the conduction gap on a real-time basis and would be useful in beating-heart epicardial ablation in off-pump setting.
    Innovations Technology and Techniques in Cardiothoracic and Vascular Surgery 11/2012; 7(6):429-34. DOI:10.1097/IMI.0b013e318280603f
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    ABSTRACT: The patient was a 29-year-old male who had been diagnosed with transposition of the great arteries with an intact ventricular septum. At the age of 6 months, he underwent a Senning operation. At the age of 10 years, a dual-chamber (DDD) pacemaker was implanted via the right subclavian vein for the treatment of sick sinus syndrome. At the age of 25, the generator was removed due to a lead fracture, and a new pacemaker was implanted via the left subclavian vein, leaving the previous lead in the right subclavian vein. Later, the patient developed pain in the right precordium, cramping of the major pectoral muscle, and non-sustained ventricular tachycardia, suggesting physical stimulation of the left ventricle (functional right ventricle) by the residual leads. Therefore, lead extraction using an excimer laser sheath was planned. However, the leads adhered strongly to the vessels, and extraction was considered to involve a high risk of injury to the blood vessels, particularly the superior vena cava (SVC). We inserted a thoracoscope via the right precordial third intercostal space and observed the SVC via the thoracic cavity in order to immediately detect any complications. Using this approach, it was possible to extract the lead safely with an excimer laser sheath.
    Journal of Arrhythmia 08/2012; 28(4):247–249. DOI:10.1016/j.joa.2012.03.013
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    ABSTRACT: We present two cases with an occluded left subclavian artery requiring coronary artery bypass grafting. A preoperative angiogram confirmed that the subclavian artery, including the internal thoracic artery distal from the occlusion, was thoroughly intact, in both cases. Immediately after reconstructing the subclavian artery using an aortoaxillary bypass with an 8 mm ring-reinforced polytetrafluoroethylene graft, each patient underwent double coronary artery bypass grafting using the affected left internal thoracic artery with either the right internal thoracic artery or a saphenous vein in the same anesthetic setting. Symptomatic relief was excellent In both cases, a postoperative angiographic study showed good function of the left internal thoracic artery graft supplying blood to the coronary artery through the aortoaxillary bypass graft. Key wordssubclavian artery occlusion–internal thoracic artery–CABG
    The Japanese Journal of Thoracic and Cardiovascular Surgery 04/2012; 48(8):524-527. DOI:10.1007/BF03218191
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    ABSTRACT: An electroanatomic mapping system using an electromagnetic navigation technology constructs a 3-dimensional structure of the heart with high geometric accuracy of the data that provides a precise localization of the substrates of arrhythmias. The system was tested for the feasibility and efficacy in intraoperative mapping. The strength of the magnetic field is measured by a location sensor with three different frequencies generated by a location pad placed beneath the operating table, and the spatial location of the sensor is determined. By roving the catheter on the heart while the local electrogram is recorded simultaneously, the 3-dimensional figure of the heart is reconstructed and an activation or voltage map is generated. The system was used in 19 patients with ventricular tachycardia or other arrhythmias. The focus or reentrant circuit of the tachycardia was precisely located and a map-guided procedure was successfully performed in all patients. Cardiopulmonary bypass allowed for the tachycardias to be mapped without any hemodynamic compromise. Intraoperative mapping using the electroanatomic mapping system enables a precise localization of the tachycardia substrate.
    The Annals of thoracic surgery 04/2012; 93(4):1285-8. DOI:10.1016/j.athoracsur.2011.12.081 · 3.65 Impact Factor
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    ABSTRACT: Atrial fibrillation is one of the most common postoperative arrhythmias following cardiac surgery. Despite many clinical studies, there is still no consensus on the most appropriate prevention strategy for atrial arrhythmia. A randomized prospective trial was conducted to determine the efficacy of intravenous landiolol administration in the early period after off-pump coronary artery bypass grafting (CABG) followed by treatment with carvedilol for prevention of atrial fibrillation. Seventy consecutive patients were enrolled in the study prospectively. Patients in the treated group received landiolol intravenously (5 μg/kg/min) in the ICU immediately after surgery. Heart rate was maintained at 60-80 bpm and intravenous landiolol was continued at 0-10 μg/kg/min until oral drug administration was possible. All patients received oral carvedilol (2.5-5 mg/day) after extubation and this was continued postoperatively. The primary endpoint was the overall development of postoperative atrial fibrillation. Postoperative atrial fibrillation occurred in 4 (11.1%) of the 36 patients in the landiolol group, compared with 11 (32.3%) of the 34 patients in the control group, indicating that development of atrial fibrillation was significantly inhibited by landiolol (P=0.042). No major postoperative complications occurred in the landiolol group. Postoperative intravenous landiolol therapy followed by oral carvedilol may be more effective than oral carvedilol alone for prevention of atrial fibrillation after off-pump CABG. We also found that intravenous landiolol is well tolerated after cardiac surgery.
    The Journal of cardiovascular surgery 01/2012; 53(3):369-74. · 1.37 Impact Factor
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    ABSTRACT: Standard surgical methods for managing true aneurysms of the deep femoral artery have not been established because these aneurysms are rare. An 85-year-old man, who had a ruptured aneurysm of the deep femoral artery, underwent aneurysmectomy and distal reconstruction with a contralateral autologous vein graft. Three-dimensional computed tomography is a valuable diagnostic modality to evaluate synchronous aneurysms and peripheral arterial circulation for treatment planning. Because of their etiology, aneurysms of the deep femoral artery should be treated with revascularization when technically feasible, even if the superficial femoral artery is patent. A contralateral saphenous vein may be the preferred conduit because ipsilateral venous stasis is likely.
    Journal of Nippon Medical School 01/2012; 79(5):377-80. DOI:10.1272/jnms.79.377 · 0.59 Impact Factor
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    ABSTRACT: This study investigated the relation between the cause of blunt cardiac injury and areas of damage. For the purpose of injury prevention, we also examined traffic accident cases in a micro study using engineering-based medicine. Among the 2673 patients transported to our facility within the 15-month period from February 2009 to April 2010, there were 12 cases of cardiac perforation. We studied these cases anatomically to evaluate the morphology of the damaged cardiac areas. We conducted a detailed micro-study in two cases regarding the circumstances surrounding the traffic accident and the vehicular damage. Subjects were nine men (mean age 64 years). The mean Injury Severity Score was 54.0 ± 19.6, and the probability of survival was 0.147. The actual survival rate was 16.7% (2 survivors, 10 deaths). Lesion sites in the 12 cases (21 sites in total) were the right atrium in 8 cases, superior and inferior vena cava in 5 cases, right ventricle in 4 cases, pulmonary artery and left atrium in 1 case each, and pulmonary vein in 2 cases, excluding the left ventricle and ascending aorta. In three cases, the aortic isthmus was also injured. Blunt cardiac injury was more common on the right side chamber. The survival rate was extremely close to the calculated survival probability. Proper seatbelt usage is important for the prevention of blunt cardiac injury due to traffic accidents. Increased severity of injury may be associated with accidents involving light motor vehicles.
    General Thoracic and Cardiovascular Surgery 01/2012; 60(1):31-5. DOI:10.1007/s11748-011-0853-6
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    ABSTRACT: Platelet-rich plasma (PRP) contains numerous growth factors that have angiogenic activities. However, the PRP-induced angiogenesis is limited by the short half-life period of growth factors. A new drug delivery system of biodegradable gelatin hydrogel was designed to achieve the controlled release of growth factors in PRP. The purpose of this study is to demonstrate the therapeutic efficacy of slow-release of PRP in the inducing of angiogenesis for critical ischemia. The PRP was prepared from the whole blood of inbred rats. Thirty-two rats underwent excision of the left femoral artery and its branches to create critical limb ischemia. The rats were randomized into four groups (n=8 each): no treatment (control), intramuscular injection of platelet-poor plasma (PPP), PRP only, or a combination of PRP and gelatin hydrogel (PRP+Gel). Four weeks after the treatment, angiogenesis was evaluated by laser doppler, microangiogram, and immunohistology. The resultant number of platelets for PRP was higher than that of PPP (p<0.01). The concentrations of vascular endothelial growth factor, transforming growth factor-β1, and platelet-derived growth factor-BB were significantly higher in PRP animals than in PPP (p<0.01). Although the PRP group improved tissue blood flow (82.7%±6.2%) compared with the control group or PPP group (69.6±12.2 or 72.2±11.8%, p<0.05), the improvement of blood flow in the PRP+Gel group was significantly better (95.1%±8.0%, p<0.05) than in the PRP group. Angiographic score in the PRP+Gel group was significantly higher than that in the control, PPP, and PRP groups (8.6±2.1 versus 3.8±0.8, 3.7±0.6, and 5.6±1.5, respectively; p<0.01). Capillary density also increased immunohistologically in the PRP+Gel group when compared with the control, PPP, and PRP groups (p<0.01). A controlled release system of PRP was effective in inducing angiogenesis for critical ischemia. The biodegradable gelatin hydrogel incorporating PRP as applicable could possibly be used to treat for patients with ischemic cardiomyopathy.
    The Annals of thoracic surgery 09/2011; 92(3):837-44; discussion 844. DOI:10.1016/j.athoracsur.2011.04.084 · 3.65 Impact Factor
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    Journal of Interventional Cardiac Electrophysiology 06/2011; 33(1):109-12. DOI:10.1007/s10840-011-9592-y · 1.55 Impact Factor
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    ABSTRACT: Background: Because placement of a coronary sinuslead is not alwayspossible for anatomical or technical reasons, surgical implantation of anepicardial LV lead is occasionally indicated. There are two different surgical approaches: a median sternotomyand a left-lateral mini thoracotomy, and bothsuture and screw types of myocardial lead have unique specification. Methods: The manipulation performance was compared between the two types of lead in 57 patients who underwent surgical implantation of anLV epicardial lead from 2000 to 2010. Serial changes in the LV pacing threshold were examinedin 10 patients (suture and screw type in 5 patients each) at implantation, 1 week, and 3 months after implantation. Results: The median sternotomy approach allowed the suture type lead to be implanted easily and freely on any desired site on the high lateral LV wall, because of the widely opened operating field. Meanwhile the left-lateral mini thoracotomyapproach provided a limited field of the high lateral LV and allowed only the screw type lead to be implanted. There was no significant serial change in the pacing threshold in both suture and screw types and no significant difference between the types (suture type: 1.56±1.2 V, 1.42±1.0 V, 1.12±0.8 V, screw type: 1.56±1.3 V, 1.22±0.5 V, 1.36±0.4 V, at implantation, 1 week, and 3 months after implantation, respectively). Conclusion: The suture type is recommended in the surgery through a median sternotomy and the screw typelead through a left-lateral mini thoracotomy.
    Journal of Arrhythmia 01/2011; 27(Supplement):OP54_1. DOI:10.4020/jhrs.27.OP54_1

Publication Stats

529 Citations
137.78 Total Impact Points


  • 1991–2013
    • Nippon Medical School
      • • Department of Cardiovascular Surgery
      • • Nippon Medical School Hospital
      • • Department of Surgery
      Edo, Tōkyō, Japan
  • 2007
    • University of Florence
      Florens, Tuscany, Italy