Masami Ochi

Nippon Medical School, Edo, Tōkyō, Japan

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Publications (112)143.05 Total impact

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    ABSTRACT: Coronary injury is a crucial complication of ablation on the posterior mitral annulus (PMA). Fifty autopsy heart specimens were classified into different types according to the final branch of the left circumflex coronary artery. The no-coronary area on the PMA was examined in each type. The posterolateral type was most common (39/50); the no-coronary area was located between 50.7%±6.5% and 83.5%±8.0% on the PMA. Ablations at 38.6%±5.2% (for catheter intervention) and the middle point (for surgery) appear safe for the obtuse marginal type but not for the posterolateral type. Thus, the no-coronary area should be considered during PMA ablation.
    Journal of Arrhythmia 12/2014; 30(6):444-445. DOI:10.1016/j.joa.2013.11.003
  • Circulation Journal 10/2014; 78(10):2521-2562. DOI:10.1253/circj.CJ-66-0096 · 3.94 Impact Factor
  • Yuji Maruyama · Masami Ochi
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    ABSTRACT: There are several issues regarding surgical revascularization for Kawasaki coronary disease including (1) the choice of conduits and (2) the optimal timing and correct indication for coronary artery bypass grafting(CABG). The internal thoracic artery(ITA) is the best conduit in terms of growth potential for pediatric CABG and for excellent long-term patency. The use of saphenous vein graft should be avoided unless an ITA is unavailable. The indication of CABG for Kawasaki coronary disease has not been established. In principle, coronary aneurysms should be observed continuously for 1 to 2 years under restrictive anticoagulation therapy, because regression of coronary aneurysm often occurs in 50 % within 1 to 2 years. The presence of severe ischemia in giant coronary aneurysms involving either the left main trunk or left anterior descending coronary artery is an absolute indicator for CABG. In addition, giant aneurysms with recurrent thrombosis under restrictive anticoagulation therapy or with severe delayed flow without significant localized stenosis may be an indication for CABG.
    Nippon rinsho. Japanese journal of clinical medicine 09/2014; 72(9):1669-76.
  • 01/2014; 43(5):239-253. DOI:10.4326/jjcvs.43.239
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    Yuji Maruyama · David J Chambers · Masami Ochi
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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 11/2013; 80(5):328-41. DOI:10.1272/jnms.80.328 · 0.58 Impact Factor
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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 · 3.85 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 · 1.16 Impact Factor
  • Surgical Science 01/2013; 04(12):535-542. DOI:10.4236/ss.2013.412104
  • Yuji Maruyama · Masami Ochi
    01/2013; 19(2):171-178. DOI:10.7793/jcoron.19.016
  • Shunichi Ogawa · Masami Ochi
    01/2013; 19(2):159-159. DOI:10.7793/jcoron.19.013
  • Hajime Imura · Hiroshige Murata · Masami Ochi
    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 · 14.43 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. © 2012 The Editorial Committee of Annals of Thoracic and Cardiovascular Surgery. All rights reserved.
    11/2012; 19(3). DOI:10.5761/
  • Yuji Maruyama · Masami Ochi · Kazuo Shimizu
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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 11/2012; 79(5):377-80. DOI:10.1272/jnms.79.377 · 0.58 Impact Factor
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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 · 3.85 Impact Factor

Publication Stats

566 Citations
143.05 Total Impact Points


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