Mitsuhiro Yamamura

Beneficial effects of mini-cardiopulmonary bypass on hemostasis in coronary artery bypass grafting: analysis of inflammatory response and hemodilution.

We compared the inflammatory response, hemodilution, and blood loss in patients who underwent mini-cardiopulmonary bypass (CPB) or conventional CPB during coronary artery bypass grafting (CABG). Ninety-eight consecutive patients with ischemic heart disease were randomly assigned to mini-CPB (n = 34) or conventional CPB (n = 64). Interleukin (IL) −8 and neutrophil elastase levels were measured before and after surgery. Hemodilution during CPB, blood loss during and after surgery were also evaluated. Compared with the conventional group, the mini-CPB group had lower levels of IL-8 on postoperative day 1 (8.3 ± 6.4 vs. 19 ± 11 pg/mL, p = 0.016) and of neutrophil elastase on postoperative days 1 (127 ± 52 vs. 240 ± 100 &mgr;g/L, p = 0.013) and 2 (107 ± 17 vs. 170 ± 45 &mgr;/L, p = 0.0001). The mini-CPB group also has less blood loss during (620 ± 595 vs. 978 ± 658 mL, p = 0.012) and after the operation (578 ± 310 vs. 1,002 ± 651 mL, p = 0.0034) and a hemodilution ratio of 14 ± 2 vs. 25% ± 3%, p < 0.0001. Thus, mini-CPB attenuated the inflammatory response and hemodilution, resulting in blood conservation in patients undergoing CABG.

Long-term results of mitral valve replacement: biological xenograft versus mechanical valves

Abstract We studied 279 patients who underwent mitral valve replacement at the Department of Thoracic and Cardiovascular Surgery, Hyogo College of Medicine, between November 1973 and December 1998. The patients were divided into two groups based on the type of replacement valve (154 patients in the biological xenograft group and 125 patients in the mechanical valve group), and the long-term results were compared. Clinically satisfactory results were obtained in both the biological xenograft group and the mechanical valve group according to the surgical results, long-term survival, and incidence of prosthetic valve endocarditis. At 15 years, fewer patients in the mechanical valve group than in the biological xenograft group were free of bleeding events (92.5 ± 3.7% vs 100% P < 0.05). At 15 years, the biological xenograft group was lower than the mechanical valve group with respect to freedom from thromboembolism (72.2 ± 4.6% vs 93.5 ± 3.6% P < 0.01), freedom from valve failure (22.0 ± 5.2% vs 87.0 ± 4.1% P < 0.005) and freedom from cardiac events (16.5 ± 3.9% vs 47.2 ± 14.5% P < 0.01). Though it has previously been suggested that biological xenografts used in mitral valve replacement do not need anticoagulation, the current study suggests the need for anticoagulation with the use of biological xenografts. Mechanical valves require close monitoring of anticoagulation, but their use has decreased the incidence of valve failure and thromboembolism, as compared with the use of biological xenografts. Therefore, mechanical valves are currently the preferred choice for mitral valve replacement. We believe that biological xenografts are indicated only for the older patient (≧65 years).

Evaluation of closed cardiopulmonary bypass circuit for aortic valve replacement.

Since 2005, we have used a novel technique based on the closed cardiopulmonary bypass system without cardiotomy suction (minimal cardiopulmonary bypass [mini-CPB]) for aortic valve replacement (AVR). In this study, we investigated the clinical advantages of this approach. We prospectively studied 32 patients who underwent isolated AVR using the mini-CPB (group M, n = 13) or conventional CPB (group C, n = 19). We compared the hemodilution ratio, serum interleukin (IL)-6 and IL-8 levels, and blood transfusion volume between the two groups. The characteristics, duration of CPB, and aortic cross-clamping time did not differ between the two groups. The hemodilution ratio was significantly lower in group M just after starting CPB (M vs. C: 14% ± 2% vs. 25% ± 3%, p = 0.0009). IL-6 levels increased significantly after surgery in both groups, but the postoperative levels were significantly lower in group M at 6 (84.9 ± 24.9 pg/ml vs. 152 ± 78 pg/ml, p = 0.042) and 12 (72.7 ± 36.1 pg/ml vs. 123 ± 49.6 pg/ml, p = 0.029) hours after CPB. There were no differences in IL-8 or blood transfusion volume after CPB. Mini-CPB offers an alternative to conventional CPB for AVR and has some advantages regarding hemodilution and serum IL-6 levels. However, it is unlikely to become the standard approach for AVR because there are no marked clinical advantages of mini-CPB.

Pretreatment with the Free Radical Scavenger Edaravone Mitigates Kidney Glycogen Depletion and Neutrophil Infiltration after Leg Ischemia in a Rat Model: A Pilot Study

Objective: We have previously shown that pretreatment with the free radical scavenger edaravone (Radicut®, Mitsubishi Tanabe Pharma Co., Japan) mitigated skeletal muscle damage due to ischemia reperfusion. In this study, we sought to validate its use in an experimental model of myonephropathic-metabolic syndrome (MNMS). Methods: Either edaravone (3.0 mg/kg; edaravone group; n=4) or saline (saline group; n=6) was intraperitoneally injected into male Lewis rats (508±31 g). Normal kidneys were harvested as control (n=3). MNMS was induced by bilaterally clamping the common femoral arteries for 5 h and declamping 5 h later. Kidney damage was evaluated by quantifying Periodic Acid Schiff (PAS)-positive area (glycogen storage) and esterase-positive cells (neutrophil infiltration). Results: The PAS-positive area in the saline group was significantly lower than that in the normal group (36.9±2.6 vs. 66.9±1.2%, P<0.01); the PAS-positive area in the edaravone group remained comparable to that in the normal group (52.9±0.9%, P<0.01). Esterase-positive cells in the saline group were significantly higher than in normal kidneys (62.4±5.6 vs. 17.5±2.4 cells/mm2, P<0.01), while they were significantly reduced in the edaravone group (32.8±5.7 cells/mm2, P<0.01). Conclusion: Edaravone pretreatment mitigates MNMS-induced kidney damage by reducing both glycogen depletion and neutrophil infiltration.

The Effects of FR-167653 on Postoperative Intimal Hyperplasia of the Interposition Vein Graft in Rat: 2nd Report.

われわれは,すでにTNF-α産生阻害剤でp38 mitogen-activated protein kinase阻害剤でもあるFR-167653(Fujisawa Pharm. Co., Ltd., Osaka)によって,ラットinterposition vein graftモデルにおける術後内膜肥厚が抑制される可能性を報告した.今回,FR-167653の投与時期および投与量を変えて比較検討し,術後内膜肥厚を抑制する作用機序について考察した.顕微鏡手術下にLewisラット(雄,484±5g)の総大腿動脈に腹壁静脈グラフトを端々吻合した.手術開始直前にFR-167653 2.0μg/gを腹腔内投与した群(単回投与群,n=5),直前および術後2週目に追加投与した群(追加投与群,n=5),4.0μg/gを直前に投与した群(倍量投与群,n=5),同量の生理食塩水を投与した群(コントロール群,n=6)の4群に分け,術後内膜肥厚の程度を比較検討した.術後4週目に腹壁静脈グラフトを採取し,コンピューター画像処理(NIH Image Ver. 1.61)により内膜断面積を測定した.術後内膜肥厚はコントロール群0.43±0.05mm2で,単回投与群0.16±0.06mm2(p<0.01),追加投与群0.25±0.02mm2(p<0.01),倍量投与群0.05±0.02mm2(p<0.001)と,コントロール群に比し有意に抑制された.本研究によって,FR-167653が,ラットinterposition vein graftモデルにおいて術後内膜肥厚を抑制する効果を有することが明らかになった.

Surgical Treatment for Cardiac Myxomas. 20 Years' Experience in Consecutive 17 Cases.

今回われわれは当科において過去20年間に経験した心臓粘液腫連続17例の臨床像・手術術式・手術成績について検討を加えた. 男性5例・女性12例, 年齢は22～78歳 (平均55歳), 発生部位は左房13例・右房2例・右室1例・多発例1例であった. 左房粘液腫摘出術は2例を除き, 両心房縦切開を用いた心房中隔合併切除・腫瘍摘出術を標準術式とし, うち2例に僧帽弁輪縫縮術を追加した. 摘出した粘液腫の重量は6～310g (平均54g) であった. 手術・病院死亡はなかったが, 術後9年目に再発1例 (多発例・他院にて再手術) を認めた. おもな術後合併症は洞不全症候群 (ペースメーカー植え込み術) を1例, 術後一過性心房細動を2例, 術後急性肺水腫 (右室粘液腫摘出術直後) を1例認めた. 長期遠隔成績は追跡率100%, 平均観察期間約7年1カ月で, 17例中2例を非心臓死で失い, 10年累積生存率は75% (n=6) であった. 左房粘液腫に対しては発生母地を直視下に観察でき腫瘍を en bloc に摘出できる両心房縦切開を用いた心房中隔合併切除・腫瘍摘出術は有用であると思われる.