Chiaki Kondo

Platelet dysfunction during cardiopulmonary bypass surgery : with special reference to platelet membrane glycoproteins

Changes in platelet membrane glycoproteins (GPIb, GPIIb/IIIa, and GMP-140) were evaluated using flow cytometry after binding with monoclonal antibodies in 22 adult patients undergoing cardiopulmonary bypass (CPB) surgery. The amount of GPIb on platelets decreased significantly during CPB, reaching a minimum level of 64 +/- 26% of the pre CPB value at 120 min of CPB. There was no significant change in the amount of GPIIb/IIIa on platelets. In accordance with these changes, ristocetin induced agglutination decreased to 56.7 +/- 16.2% of the pre CPB value during CPB. However, there were no significant changes in ADP and collagen induced aggregation throughout the procedure. The number of the activated platelets expressing GMP-140 on their surfaces increased significantly during CPB. There was an upper limit to the amount of GMP-140 expression on each platelet in the circulating blood, suggesting that excessively activated platelets are removed from the circulation. The authors conclude that CPB reduces the amount of GPIb on platelets, which results in platelet dysfunction. In addition, removal of excessively activated platelets from the circulation may lead to thrombocytopenia after CPB.

Effects of nafamostat mesilate on platelets and coagulofibrinolysis during cardiopulmonary bypass surgery.

The effect of nafamostat mesilate (FUT-175) on platelet membrane glycoproteins and the coagulofibrinolytic system were analyzed. Twenty-five patients undergoing aorto-coronary bypass surgery were randomly distributed into an FUT treated group and a control group. In the control group, anticoagulation was achieved with sodium heparin (3 mg/kg) immediately before cardiopulmonary bypass (CPB). In the FUT treated group, in addition to the usual treatment with heparin, FUT-175 was infused continuously at a rate of 2 mg/kg/hr. In the control group, alpha 2 plasmin inhibitor/plasmin complex (PIC) and fibrinogen/fibrin degradation products (FDP) D-dimer increased significantly during CPB, reaching 6.1 +/- 5.1 micrograms/ml and 576 +/- 200 ng/ml, respectively, at 60 min of CPB. PIC and FDP D-dimer remained significantly lower in the FUT treated group than in the control group. GPIb on platelets decreased significantly in both groups, but remained higher in the FUT treated group (81 +/- 5% vs. 56 +/- 21% at 60 min of CPB, P < 0.01). There were no significant changes in GPIIb/IIIa on platelets throughout the procedure in either group. Blood loss after CPB was significantly lower in the FUT treated group than in the control group (778 +/- 277 ml vs. 1,342 +/- 426 ml, P < 0.01). The authors conclude that FUT-175 improves hemostasis after CPB, not only by inhibiting fibrinolysis, but also by preserving platelet GPIb during CPB.

Selective cerebral perfusion in patients with aortic aneurysms involving the aortic arch.

Patients with aortic arch aneurysms underwent surgery using a selective cerebral perfusion (SCP) method. For this purpose, a protocol for SCP was established on the basis of an animal experimental study. Our SCP procedure is performed at a perfusion rate of 6 ml/kg/min with the patient under deep hypothermia at 20 degrees C. The subject group in the current study included 36 patients, 28 men and eight women, ranging in age from 23 to 84 years (mean, 61). There were five operative deaths (13.9%). The mean cardiopulmonary bypass time was 288 minutes, and the mean aortic clamp time was 135 minutes. Mean SCP time was 89 minutes, exceeding 90 minutes in 17 cases. The mean blood pressure during SCP was 43 mmHg and oxygen saturation rate in the internal jugular vein was at least 90%. There was no definite production of lactate in the brain. Cerebral disorders considered to have been caused by SCP occurred in only two cases. It appears that cerebral metabolism can be maintained safely, and that our SCP method is useful during surgery for aortic arch aneurysms.

Recent Surgical Results of Transverse Aortic Arch Replacement.

当科で行っている弓部大動脈瘤手術の脳保護法,末梢吻合における工夫について報告する.対象は1997年2月から2001年10月までに施行した弓部大動脈瘤手術32例.疾患の内訳は真性瘤18例,解離性大動脈瘤13例,仮性瘤1例で,緊急症例を9例含む.脳保護法は順行性脳灌流(SCP)と逆行性脳灌流(RCP)を組み合わせて用いている.つまり循環停止後,瘤を切開すると同時にRCPを開始,病変を検索し1分枝以下の再建ならRCPのまま手術を進め,2分枝以上の再建が必要ならRCP下に血液を逆流させながら弓部分枝にカニュレーションしSCPに移行する.また末梢側吻合の工夫として,急性解離ではadventitial inversion法,真性瘤では自己心膜を大動脈内面に補填することで止血の補助とした.最近の10症例ではカフ付きグラフト法を用いており,これにより手技的に非常に容易となり,すばやく確実な吻合が可能である.以上の方針の結果,術後覚醒時間8.7±1.4時間,病院死2例(6.3%),脳合併症2例(6.3%)であった.弓部大動脈手術の手術成績向上には安定した脳保護法の確立と,迅速で確実な末梢吻合を行うことにある.今回報告した脳保護法,末梢吻合における当科の方法は手術成績からみて有用である.