S Ishimaru

Kosei Chuo General Hospital, Edo, Tōkyō, Japan

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Publications (109)153.62 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Stent-grafts for endovascular repair of thoracic aortic aneurysms have been commercially available for more than ten years in the West, whereas, in Japan, a manufactured stent-graft was not approved for the use until March 2008. Nevertheless, endovascular thoracic intervention began to be performed in Japan in the early 1990s, with homemade devices used in most cases. Many researchers have continued to develop their homemade devices. We have participated in joint design and assessment efforts with a stent-graft manufacturer, focusing primarily on fenestrated stent-grafts used in repairs at the distal arch, a site especially prone to aneurysm. In March 2008, TAG (W.L. Gore & Associates, Inc., Flagstaff, Arizona, USA) was approved as a stent graft for the thoracic area first in Japan, which was major turning point in treatment for thoracic aortic aneurysms. Subsequently, TALENT (Medtronic, Inc., Minneapolis, Minnesota, USA) was approved in May 2009, and TX2 (COOK MEDICAL Inc., Bloomington, Indiana, USA) in March 2011. Valiant as an improved version of TALENT was approved in November 2011, and TX2 Proform as an improved version of TX2 began to be supplied in October 2012. These stent grafts are excellent devices that showed good results in Western countries, and marked effectiveness can be expected by making the most of the characteristics of each device. A clinical trial in Japan on Najuta (tentative name) (Kawasumi Labo., Inc., Tokyo, Japan) as a line-up of fenestrated stent grafts that can be applied to distal arch aneurysms showing a high incidence, and allow maintenance of blood flow to the arch vessel was initiated. This trial was completed, and Najuta has just been approved in January of 2013 in Japan, and further development is expected. In the U.S., great efforts have recently been made to develop and manufacture excellent stent grafts for thoracic aneurysms, and rapid progress has been achieved. In particular, in the area of the aortic arch, in which we often experience aneurysmal change, but there are no commercially available devices which are urgently needed. Companies are competing keenly to develop devices. To our knowledge, more than 4 manufacturers are involved in the development of functionally new stent grafts in this area. The introduction of branched stent grafts may not be faraway.
    Annals of Vascular Diseases 01/2013; 6(2):129-36.
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    ABSTRACT: Hepatocyte growth factor (HGF) is a potent angiogenic factor. The efficacy and safety of intramuscular injection of a naked plasmid encoding human HGF gene (beperminogene perplasmid, Collategene) was investigated in patients with critical limb ischemia (CLI) in a multicenter, randomized, double-blind, placebo-controlled trial. The randomization ratio for plasmid to placebo was 2:1. Injection sites were selected in each patient limb based on angiographic findings. Placebo or plasmid was injected on days 0 and 28. Evaluation of efficacy was carried out after 12 weeks. The primary end point was the improvement of rest pain in patients without ulcers (Rutherford 4) or the reduction of ulcer size in patients with ulcer(s) (Rutherford 5). Secondary end points were ankle-brachial pressure index, amputation, and quality of life (QOL). Forty-four patients were treated, and we performed interim analysis of efficacy in 40 patients. The overall improvement rate of the primary end point was 70.4% (19/27) in HGF group and 30.8% (4/13) in placebo group, showing a significant difference (P=0.014). In Rutherford 5 patients, HGF achieved a significantly higher improvement rate (100% [11/11]) than placebo (40% [2/5]; P=0.018). HGF plasmid also improved QOL. There were no major safety problems. HGF gene therapy is safe and effective for CLI.
    Gene therapy 09/2010; 17(9):1152-61. · 4.75 Impact Factor
  • Y Obitsu, S Ishimaru, H Shigematsu
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    ABSTRACT: The Japanese Committee for Stentgraft Management (JACSM) was established with the aim of ensuring the safe and proper reach of commercial stent grafts following their regulatory approval. This study examines the validity of the practice standards developed by JACSM. JACSM comprises 10 associations related to endovascular treatment. Based on the practice standards developed by JACSM, the status of practising institutions, practising surgeons, supervising surgeons and the results of follow-up surveys were analysed. In the 2.5 years following the establishment of JACSM, 298 institutions have fulfilled the practice standards. The number of practising surgeons reached 493, and the number of supervising surgeons reached 177. There were 3089 registered cases up to June 2009. The present study analysed 1570 cases registered in the 2 years from July 2006 to June 2008. The hospital mortality rate was low (0.4%) in the follow-up surveys. Early results following the introduction of stent grafts were generally good. The procedure spread safely without the learning curve seen in the initial stages following introduction of new medical materials, indicating that the practice standards were appropriate.
    European journal of vascular and endovascular surgery: the official journal of the European Society for Vascular Surgery 02/2010; 39 Suppl 1:S5-9. · 2.92 Impact Factor
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    ABSTRACT: Obstruction of the endograft limb by thrombosis has often been reported and may cause fatal complications such as leg necrosis or myonephropathic metabolic syndrome. The purpose of this study was to evaluate endograft antithrombogenicity by indium-111 platelet scintigraphy. Seventeen patients with abdominal aortic aneurysms were treated by endografting. Thirteen patients were treated with conventional open surgery using an artificial graft. The endograft was constructed from a self-expanding Z-shaped stent and woven polyester fabric. Autologous platelets labeled with indium-111 were injected at 2 weeks postoperatively. At 24 hours and 72 hours postinjection, the ratio of scintillation count of the endograft or graft to that of the native artery was calculated to assess platelet deposition. The normalization ratio was calculated as follows: (scintillation count per pixel of endograft or graft/circumference)/(scintillation count per pixel of the native femoral artery). Platelet factor 4 and beta-thromboglobulin were measured to evaluate the systemic platelets activity at 2 weeks postoperatively. There was no significant difference in platelet counts or labeling efficiency between the groups. The ratio was significantly higher in the endografting group than in the open surgery group at 72 hours postinjection (2.5-0.7 vs 3.9-1.1, P<.001). There was no significant difference in platelet factor 4 and beta-thromboglobulin between the groups. Although there was no difference in systemic platelet activity, endografting was associated with lower antithrombogenicity. It remains unclear whether lower antithrombogenicity causes thromboembolism as a complication of the procedure. The authors recommend the administration of antiplatelet drugs to prevent endograft obstruction in patients with very narrow iliac arteries.
    Vascular and Endovascular Surgery 10/2006; 40(5):374-82. · 0.77 Impact Factor
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    ABSTRACT: The effectiveness of low-density lipoprotein (LDL) apheresis for patients with peripheral arterial disease (PAD) was investigated to confirm a hypothesis based on subjective evidence that the amelioration of blood rheology would be the most contributing factor for improvement in clinical symptoms. Evaluation of the severity of intermittent claudication is difficult because of the lack of an accurate parameter to assess muscle ischemia during exercise, thus we objectively evaluated by non-invasive near-infrared spectroscopy (NIRS) on a treadmill in this study. Thirty-one patients with PAD were evaluated for hemostatic function and physiological parameters such as ankle-brachial pressure index (ABI), maximum tolerated walking distance (MTWD) and recovery time (RT) or recovery ability index (RAI) on NIRS. Laboratory tests included plasma assays of total cholesterol, LDL-cholesterol, high-density lipoprotein (HDL) cholesterol, triglyceride, and fibrinogen. The change in red-cell filtration rate was evaluated for the improvement of microcirculation. Statistical analysis was performed using the paired Student's t-test with Bonferroni's correction. A significant improvement in ABI and MTWD was observed after average 9.6+/-0.8 sessions of LDL apheresis treatment and the amelioration of microcirculation in ischemic muscle was objectively evaluated as significant improvement in RAI on NIRS. Rest pain was improved in all 5 patients with Fontaine's classification III or IV. A severe ulcer refractory to usual medications was dramatically diminished in the area by 10 sessions of LDL apheresis and fully healed 5 months after the final LDL apheresis treatment followed by medication. No angiographical change was observed in the arterial occlusive lesions in any patients. The effectiveness of LDL apheresis on the improvement in physiological parameters such as ABI, MTWD and clinical symptoms in patients with PAD was confirmed. The severity of intermittent claudication was objectively evaluated using non-invasive NIRS. The RT or RAI was useful parameter to evaluate the improvement in the ischemic symptoms of the extremities.
    International angiology: a journal of the International Union of Angiology 10/2006; 25(3):287-92. · 1.01 Impact Factor
  • S Kawaguchi, S Ishimaru
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    ABSTRACT: Despite advances in operative technique and management having improved the clinical outcomes of conventional open surgical replacement for thoracic aortic aneurysms, it remains an invasive procedure especially for aged patients. Over the past 10 years, minimally invasive endovascular surgery using a stent graft, has made significant advances for the treatment of aneurysms. For 10 years from 1995, 476 patients of thoracic aortic aneurysms were treated with the endovascular technique using the stent graft in our hospital. Exclusion of the aneurysms without endoleak were achieved within 2 weeks postoperatively in over 95%. Also in elderly patients (46/476), same good results came out. Endovascular stent grafting shows potential as a safe and useful treatment for thoracic aortic aneurysms, but further investigation should attempt to determine its efficacy over a longer postoperative period.
    Kyobu geka. The Japanese journal of thoracic surgery 08/2005; 58(8 Suppl):689-94.
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    ABSTRACT: Native flow competition is a significant factor affecting bypass graft patency. The objective of this study was to compare the effect of competitive flow on conduit flow dynamics in the gastroepiploic artery (GEA) and the saphenous vein graft (SVG). In 51 patents, 23 GEAs (in-situ grafts) and 28 SVGs (aortocoronary grafts) were examined using a Doppler-tipped guidewire during coronary angiography after coronary artery bypass. Graft flow volume at rest and maximum graft flow volume during hyperemia were calculated from graft diameter and average peak velocity at rest and maximum average peak velocity induced by papaverine hydrochloride injection. Grafts were classified according to the grade of native coronary artery stenosis; group S (14 GEAs and 16 SVGs) displayed over 75% stenosis and group M (9 GEAs and 12 SVGs) exhibited over 50% up to 75% stenosis. In group S, no difference in flow volume was apparent between the GEA and the SVG at rest (36+/- 17 vs 42 +/- 16) and during hyperemia (78 +/- 30 vs 88 +/- 28). In group M, flow volume of the GEA was significantly lower than that of the SVG at rest (17 +/- 11 vs 38 +/- 12; p = 0.029) and during hyperemia (32 +/- 19 vs 94 +/- 46; p = 0.001). These data suggest that in intermediate coronary stenosis, GEA flow is compromised by native flow competition, whereas the SVG flow dynamics is maintained. However, the GEA can provide comparable flow capacity to the SVG and will achieve good surgical results when target coronary artery selection is appropriate.
    The Annals of thoracic surgery 08/2005; 80(1):124-30. · 3.45 Impact Factor
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    ABSTRACT: Aortic surgery is an invasive, high-risk noncardiac procedure and the patients who require it have a high prevalence of coronary artery disease. Therefore, preoperative risk stratification for this subset is essential. To assess the perioperative risk for aortic surgery, pharmacologic stress single-photon emission computed tomography (SPECT) was performed in 302 patients: aortic dissection in 56, thoracic aortic aneurysm in 124, and abdominal aortic aneurysm in 122. Not only was the presence or absence of perfusion defects analyzed, but also the 20-segment model. Pharmacologic thallium SPECT revealed negative findings in 210 patients and positives in 92. Perioperative cardiac events occurred in 9 patients: 7 occurred in patients with positive SPECT, and in only 2 of those with negative SPECT (2/210 vs 7/92; p<0.05). Multivariate analysis using logistic regression model revealed that a summed stress score>or=14 was the most important factor to identify patients who subsequently had perioperative cardiac events. Pharmacologic stress SPECT has significant value in the risk stratification of patients before aortic surgery. In patients with positive SPECT, an aggressive approach to reduce the preoperative risk is necessary, whereas aortic surgery can be performed safely in patients with negative SPECT.
    Circulation Journal 05/2005; 69(5):558-63. · 3.69 Impact Factor
  • Shin Ishimaru
    Nippon Geka Gakkai zasshi 04/2005; 106(3):226.
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    ABSTRACT: Autologous fibrin sealant (AFS) which is not based on the conventional method of co-administering fibrinogen, thrombin and aprotinin was prepared by Vivostat system, and was used in coronary artery bypass grafting (CABG). The purpose of this study was to investigate the safety and efficacy of the AFS prepared by the Vivostat system. In 6 of 68 cases of CABG, normal AFS was not prepared due to device failures. AFS was prepared and sprayed in 62 cases. There were the total of 230 anastomosis sprayed AFS and the bleeding could not seen in 225 anastomosis. Surgical hemostatic procedures (4 cases) were or other sealant usage (1 case) was performed 5 bleeding anastomosis sites. The rate of hemostasis at the anastomosis using AFS was 97.8%. This study was conducted in patients undergoing CABG. In this group of patients, a number of commercial available fibrin sealant products are routinely used. The usefulness of Vivostat as medical device to prepare and administer AFS was confirmed in this study.
    Kyobu geka. The Japanese journal of thoracic surgery 03/2005; 58(2):128-32.
  • Journal of Endovascular Therapy 03/2005; 12(1):89-97. · 3.59 Impact Factor
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    ABSTRACT: The present study was conducted to establish the cutoff value of the ankle-brachial pressure index (ABI) at which the accuracy of brachial-ankle pulse wave velocity (baPWV) measurement is diminished. The baPWV and ABI were measured in 1,361 patients with an atherosclerosis-related disease and 7,889 subjects without any atherosclerotic risk factors, in order to determine the percent difference of the brachial-ankle PWV (%baPWV), the angle of the rise of the anacrotic limb (%angle) and of the amplitude of the entire waveform (%amplitude) in both sides. The %angle and %amplitude were significantly higher in subjects whose %baPWV was >or=19% than in those subjects whose %baPWV was <19% (19% was the mean value+3SD of 7,889 healthy subjects). The %baPWV >or=19% was defined as the abnormal discrepancy of baPWV caused by arterial stenosis in both sides. The receiver operator characteristic curve discriminated the abnormal discrepancy of baPWV by ABI because the area under the curve was 0.86. The highest discriminating sensitivity and specificity were 91% and 75% at ABI =0.95. An ABI <0.95 seems to be the marker of diminished baPWV accuracy.
    Circulation Journal 01/2005; 69(1):55-60. · 3.69 Impact Factor
  • Shin Ishimaru
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    ABSTRACT: In recent years, endovascular repair with stent-grafts has made great advances as a minimally invasive alternative to conventional open surgery in the treatment of aortic aneurysm and dissection. Although many commercial endograft systems are now used worldwide for the treatment of these pathologies in the abdominal aorta, only a few dedicated stent-grafts have been developed for use in the thoracic aorta. However, these second-generation commercial endografts have almost identical specifications and performance profiles in terms of structure, function, and delivery mechanism as stent-graft systems employed in the abdominal aorta. Thus, endografts have been used in the thoracic aorta with little consideration to the morphological and hemodynamic characteristics specific to the aortic arch and the deployment techniques needed to navigate this curved region of the thoracic aorta. This review will survey the literature on aortic arch stent-graft repair and identify key elements critical to the successful design of an endograft to treat lesions in the aortic arch.
    Journal of Endovascular Therapy 01/2005; 11 Suppl 2:II62-71. · 3.59 Impact Factor
  • Tairyoku kagaku. Japanese journal of physical fitness and sports medicine 01/2005; 54(1):75-75. · 0.08 Impact Factor
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    ABSTRACT: To stratify perioperative cardiac risk for endovascular surgery, pharmacologic stress single-photon emission computed tomography (SPECT) was performed in 206 patients. Of 8 patients who had cardiac events, 7 occurred in 67 patients with positive SPECT results, whereas only 1 occurred in 139 patients with negative SPECT results (7 of 67 vs 1 of 139, p <0.002). Furthermore, a scintigraphic marker of a summed stress score >/=14 was the most important factor identifying patients who subsequently had cardiac events by multivariate analysis.
    The American Journal of Cardiology 12/2004; 94(11):1471-4. · 3.43 Impact Factor
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    ABSTRACT: Recently, a measurement device that can simultaneously measure the ankle-brachial pressure index (ABI) and brachial-ankle pulse wave velocity (PWV) has become available. The present study compares the applicability of ABI and PWV as markers for predicting the prevalence of coronary artery disease (CAD) in subjects with a high risk of atherosclerotic cardiovascular disease. The ABI and brachial-ankle PWV were measured in 472 consecutive subjects who subsequently underwent coronary angiography for diagnosis or exclusion of CAD. The prevalence of CAD in the lowest ABI quartile was higher than those in the other 3 ABI quartiles, whereas the prevalence in the lowest brachial-ankle PWV quartile was lower than those in the other 3 brachial-ankle PWV quartiles. A multivariate logistic regression analysis demonstrated that the lowest ABI quartile was a significant independent variable for the prevalence of CAD and that the lowest brachial-ankle PWV quartile was a significant independent variable for the absence of CAD in a population. Thus, a low ABI is an independent marker for an additive risk of CAD, whereas a low brachial-ankle PWV may be used as an independent marker for excluding the risk of CAD among subjects with a high risk of atherosclerotic cardiovascular disease.
    The American Journal of Cardiology 11/2004; 94(7):868-72. · 3.43 Impact Factor
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    Journal of Nuclear Cardiology 07/2004; 11(4). · 2.65 Impact Factor
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    ABSTRACT: Graft failure has been reported when the arterial conduit, such as the internal thoracic artery (ITA) or the right gastroepiploic artery (GEA), is grafted to a lower grade coronary artery stenosis. The shear stress as a significant factor affecting graft patency was compared between the arterial conduit and the saphenous vein graft (SVG) after surgery. In 101 patients, 40 ITAs, 27 GEAs and 34 SVGs were examined using a Doppler-tipped guide wire during postoperative angiography. The graft flow volume and shear stress were calculated from velocity and diameter data. The study grafts were classified according to the grade of native coronary artery stenosis: group L had more than 50 up to 75% stenosis, and group H had more than 75% stenosis. Group H consisted of 25 ITAs, 17 GEAs and 21 SVGs, while group L consisted of 15 ITAs, 10 GEAs and 13 SVGs. In group H, graft flow volume did not significantly differ among the ITA (34+/-11 ml/min), GEA (36+/-16 ml/min) and SVG (41+/-15 ml/min), and graft shear stress significantly (ITA vs. GEA P<0.0001; GEA vs. SVG P<0.01) differed among the ITA (16.0+/-4.8dyn/cm(2)), GEA (9.1+/-3.2dyn/cm(2)) and SVG (4.8+/-1.6dyn/cm(2)). In group L, flow volume was lower (P<0.001) in the ITA (18+/-6 ml/min) and GEA (13+/-8 ml/min) than in the SVG (35+/-16 ml/min), and shear stress was significantly (P<0.001) greater in the ITA (13.7+/-4.9dyn/cm(2)) than the GEA (5.6+/-2.0dyn/cm(2)) or SVG (4.6+/-2.0dyn/cm(2)). These data suggest that shear stress of the ITA is superior and maintained despite the flow volume being reduced by flow competition. Lower shear stress of the GEA for intermediate stenosis may be associated with the development of conduit failure.
    European Journal of Cardio-Thoracic Surgery 05/2004; 25(4):578-84. · 2.81 Impact Factor
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    ABSTRACT: Between October 1996 and June 2003, endovascular stent graft repair was performed in 87 patients with descending thoracic aortic aneurysms, graft replacement was performed in 24 patients with thoracoabdominal aortic aneurysms, and endovascular stent graft repair with concomitant surgical bypass of abdominal visceral arteries was performed in 3 patients with thoracoabdominal aortic aneurysms. The retrievable stent graft was inserted and evoked spinal cord potential were monitored in order to predict spinal cord ischemia for stent graft repair. There was no paraplegia or hospital death, although 3 patients had paraparesis in stent graft repair. Two of the 3 patients with paraparesis made a full neurologic recovery. There were no cases of paraplegia or paraparesis in surgical operations with thoracoabdominal aortic aneurysm. The concomitant surgical procedure was a good technique for patients in whom cardiopulmonary bypass could not be used. Our results of stent graft repair and surgical operation for descending thoracic or thoracoabdominal aortic aneurysms were acceptable. The retrievable stent graft was useful for prediction of spinal cord ischemia before endovascular stent graft repair of descending thoracic or thoracoabdominal aortic aneurysm.
    Kyobu geka. The Japanese journal of thoracic surgery 05/2004; 57(4):262-7.
  • Journal of the American College of Cardiology 03/2004; 43(5). · 15.34 Impact Factor

Publication Stats

813 Citations
153.62 Total Impact Points


  • 2010
    • Kosei Chuo General Hospital
      Edo, Tōkyō, Japan
  • 2000–2006
    • Tokyo Medical University
      • • Department of Surgery II
      • • Division of Cardiovascular Surgery
      • • Department of Internal Medicine III
      • • Division of Dermatology
      Edo, Tōkyō, Japan
  • 1999
    • The University of Tokyo
      • Department of Surgical Sciences
      Tokyo, Tokyo-to, Japan
  • 1998
    • Juntendo University
      • Department of Neurosurgery
      Edo, Tōkyō, Japan