Prolongation of total permissible circulatory arrest duration by deep hypothermic intermittent circulatory arrest

AbstractObjective: We determined whether the duration of permissible circulatory arrest could be prolonged by deep hypothermic intermittent circulatory arrest. Methods: Twenty-five beagles were cooled on bypass to 18° C to initiate deep hypothermia that was maintained for 3 hours. Five protocols were then studied: group 1, uninterrupted bypass during hypothermia; group 2, arrest for 40 minutes during hypothermia; group 3, arrest for 60 minutes during hypothermia; group 4, arrest for 80 minutes during hypothermia; and group 5, intermittent circulatory arrest, consisting of six cycles of 20 minutes of arrest followed by 10 minutes of systemic recirculation during hypothermia (total, 120 minutes of arrest). The oxyhemoglobin concentration in the brain was measured with near infrared spectrophotometry. Results: In groups 2, 3, and 4, the oxyhemoglobin concentration in the brain decreased continuously after arrest, finally reaching a plateau after 24.9 ± 1.2 minutes. This finding suggested that the available cerebral oxyhemoglobin was depleted. In contrast, the available cerebral oxyhemoglobin was not depleted during hypothermic intermittent arrest in group 5. The mitochondrial respiratory control index was significantly lower in group 4 than in the other groups (p < 0.05). However, there were no significant differences in the respiratory control index for groups 1, 2, 3, and 5. Moreover, the formation of brain edema was significantly lower in group 5 than in the other groups (p < 0.05). Conclusions: These results indicate that deep hypothermic intermittent arrest can increase the duration of total permissible circulatory arrest and will be a useful modality when prolonged arrest is anticipated. (J Thorac Cardiovasc Surg 1998;116:163-70

副腎皮質機能に占める不可欠脂酸ならびにピリドキシンの役割に関する実験的研究

京都大学0048新制・課程博士医学博士医博第192号新制||医||72(附属図書館)725京都大学大学院医学研究科内科系専攻(主査)教授 木村 忠司, 教授 荒木 千里, 教授 伊藤 鉄夫学位規則第5条第1項該当Kyoto UniversityDA

<症例>4回の開心術による癒着のため冠動脈走行が判別不能であった大動脈弁輪部膿瘍に対するトランスロケーション法における冠動脈再建の新方法

A new approach to the problem of recurrent infection of an aortic valve prosthesis in a patient with an inaccessible coronary arterial system is presented. The coronary arteries were reconstructed by anastomosing a looped ringed-PTFE graft to the left and right coronary ostia within the aorta, and the graft was withdrawn from the aorta just above th e ostia. Then the top of the looped graft was anastmosed to the aorta above a translocated aortic prosthesis. This procedure is most likely to be useful in the treatment of recurrent aortic prosthetic valv e endocarditis which has dense pericardial adhesion secondary to multiple cardiac operations. Aortic prosthetic valve endocarditis frequently is associated with a paravalvular ring abscess which may destroy the normal annulus. In these cases, translocating the aortic valve to the ascending aorta, and placing saphenous vein bypass grafts to the right and th e left anterior descending coronary arter y may be required. However, the coronary arteries may not be accesible following multipie operations. The following case illustrates a new solution to the problem how to translocated the aortic valve and reconstruct the coronary arteries in a patient with an infected aortic root and inaccessible coronary arteries.4回の関心術による癒着のため冠動脈の走行が判別不能であった大動脈弁輪部膿瘍を伴なった感染性心内膜炎症例に対し, 冠動脈再建に新しい方法を用いたトランスロケーション法を行った. 8 mmφ のリング付き PTFE 人工血管の両端を大動脈の内腔で左右冠動脈孔に縫着し, その直ぐ末梢側で一旦大動脈外にグラフトを出しそのループの頂点部を転位縫着した人工弁の末梢側で大動脈(弁付き人工血管の場合は人工血管)と側側に吻合する方法を行った. 術後経過は順調で, 狭心症, 不整脈は発生していない

<原著>心筋保護におけるグルタチオンペルオキシダーゼの重要性 : ラット心を用いて

Selenium (Se) is an integral component of glutathione poeroxidase (GSHPx), and the serum selenium concentration is age-depend. We speculated that myocardial GSHPx had relation to reperfusion injury in open heart operations, especially in infants in whom GSHPx activity is low. This study correlated GSHPx activity with the serum and myocardial selenium concentrations in Wistar rats, which were divided into three groups, infants, Se-deficient rats, and control rats. Serum GSHPx activity in infant and Se-deficient rats (22. 7± 3. 5 U/g protein, 24. 6 ± 22. 2 U/g protein) was lower than that in controls (179 ± 12. 0 U/g protein). The serum selenium concentration in infant and Se-deficient rats (3. 81 ± 0. 81 μg/g protein, 2. 06 ± 1. 69 μg/g protein) was also lower than that in controls (7. 32 ± 2. 96 μg/g protein). The myocardial GSHPx activity was significantly lower in infants and Se-deficient rats (4. 76 ± 1. 05 × 10_-1 U/mg protein, 3. 38 ± 0. 32 × 10_-1 U/mg protein) than that in controls (8. 03 ± 0. 57 × 10_-1 U/mg protein). However, the myocardial selenium concentra tion in infants (1. 42 ± 0. 24 × 10_-1μg/mg protein) was significantly higher than that in the other groups (0. 31 ± 0. 06 × 10_-1 μg/mg protein, 0. 28 ± 0. 04 × 10_-1 μg/mg protein). Next, in Se-deficient and control rats, isolated hearts were perfused for aerobically with Krebs-Henseleit solution in the Langendorff mode for 15 minutes, followed by 60 minutes of global ischemia at 4°C and then reperfused for 30 minutes in a working mode. The hemodynamic parameters were measured. The aortic pressure, LV max dp/dt, aortic flow, cardiac output and stroke volume were significantly lower in the Se-deficient rats than those of the control rats. Immediately following these measurements, the hearts were frozend in liquid nitrogen, and the myocardial lipid peroxide (TBARS) concentration was assayed and found to be significantly higher in the Se-deficient rats. The lower myocardial GSHPx activity may play a important role in vulnerability to reperfusion injury in infants as in Se-deficient rats.必須微量元素セレン(Se)は, フリーラジカルスカベンシャーの一つであるグルタチオンベルオキシダーゼ(GSHPx)の主要な構成成分である. 血清 Se 濃度は年齢により変化し新生児期, 乳児期は低い. このことが乳児期の関心術における再灌流障害に関与しているのではないかと推論した. ウィスター系ラットを乳児期ラット(乳児群), Se 欠乏食ラット(Se群), 対照成熟ラット(対照群)の3群に分けた乳児群, Se 群の血清 GSHPx 活性は, 対照群と比べ有意に低値を示した(順番に22. 7 ± 3. 5, 24. 6 ± 22. 2, 179. 0 ± 12. 0 U/g protein). 乳児群, Se 群の血清 S e濃度も同様に対照群と比べ有意に低値を示した(3. 81±0. 81, 2. 06 ± 1. 69, 7. 32 ± 2. 96 μg/g protein)・乳児群, Se 群の心筋 GSHPx 活性は対照群と比べ有意に低値を示した(4. 76 ± 1. 05 × 10_-1, 3. 38 ± 0. 32 × 10_-1, 8. 03 ± 0. 57× 10_-1 U/mg protein). しかし乳児群の心筋 Se 濃度は Se 群, 対照群と比べ有意に高値を示した(1. 42 ± 0. 24 × 10_-1, 0. 31 ± 0. 06 × 10_-1, 0. 28 ± 0. 04 × 10_-1 μg/mg protein). これとは別に Se 欠乏食ラットと対照成熟ラットの摘出心を用いて Neely JR らの working heart model により, 4°C 60分間の心停止後の心機能パラメーターを測定した. 大動脈圧, 左室 max dp/dt, 大動脈流量, 心拍出量, 一回拍出量は S e群で有意に低値を示した. また心筋内過酸化脂質(TBARS)濃度は, Se 群で有意に高値を示した. このことから, 心筋内 GSHPx 活性の低下は心筋の再灌流障害と非常に関連が深いことが示唆された