Reduction of blood utilization during myocardial revascularization.

The efficacy of four different blood conservation techniques in decreasing the homologous blood requirement in cardiac operations was studied prospectively in 100 patients undergoing myocardial revascularization. The patients were randomly assigned to four groups of 25 each as follows: group I, retransfusion of oxygenator blood after termination of extracorporeal circulation; group II, processing of oxygenator content by means of a cell separator; group III, predonation of autologous blood and isovolumetric substitution of hydroxyethyl starch (10 ml/kg bodyweight) after the induction of anesthesia in addition to the use of a cell separator; and group IV, predonation and the use of a cell separator plus postoperative retransfusion of shed mediastinal blood. To form homologous groups, we accepted only male patients without impairment of left ventricular function for the study. In addition, patients with internal mammary artery grafts and a duration of extracorporeal circulation less than 45 minutes or more than 90 minutes were excluded. The bank blood requirement during hospitalization was 2132 +/- 824 ml in group I, 1371 +/- 928 ml in group II, 833 +/- 599 ml in group III, and 408 +/- 559 ml in group IV. The use of blood conservation techniques resulted in reductions of homologous blood requirements of 34%, 60%, and 80%, respectively, in groups II to IV as compared with the requirement in group I. There were no complications related to autologous blood transfusion. We conclude that the use of blood conservation techniques can considerably reduce the homologous blood requirement in cardiac operations and therefore decrease transfusion-related risks.

Influence of desmopressin acetate on homologous blood requirements in cardiac surgical patients pretreated with aspirin.

Conflicting results have been reported concerning the effect of the synthetic vasopressin analog desmopressin acetate (DDAVP) on perioperative bleeding and homologous blood requirements in cardiac surgery. Because patients preoperatively treated with platelet-inhibiting drugs are at increased risk of perioperative bleeding, the blood-saving effect of DDAVP was investigated in 40 male patients undergoing primary myocardial revascularization. All patients had taken aspirin within the last 5 days prior to surgery. In a double-blind, randomized trial, the effects of DDAVP (0.3 microgram/kg of body weight) were compared to those of saline placebo on postoperative blood loss and the need to replace blood products. To evaluate the drug's influence on the coagulation and fibrinolytic systems, von Willebrand factor (vWF), the activities of tissue plasminogen activator (tPA) and plasminogen activator inhibitor (PAI 1), and the split products of cross-linked fibrin (D-dimers) were investigated. The total homologous blood requirement was significantly lower in DDAVP recipients (median 2, range, 0 to 5 U) compared to placebo (median 3.5, range, 0 to 8 U; P < 0.05). Although at all points of measurement (intraoperative and postoperative) transfusion requirement was less in the DDAVP group, hematocrit values of these patients always exceeded those of the placebo group, this difference being significant at the end of the operation. Because no difference in postoperative blood loss was found, the markedly reduced transfusion requirement of the DDAVP-treated patients is explained either by reduced intraoperative bleeding or by a reduced hematocrit of the chest-tube blood.(ABSTRACT TRUNCATED AT 250 WORDS)

Warfarin pretreatment does not lead to increased bleeding tendency during cardiac surgery.

OBJECTIVE: To study the influence of preoperative warfarin anticoagulation on postoperative blood loss and allogeneic blood requirement. DESIGN: Retrospective study with a matched control group. SETTING: University and community hospital, single institutional. PARTICIPANTS: 240 patients scheduled for cardiac surgery. INTERVENTIONS: Warfarin sodium was administered to 125 patients preoperatively to prevent thromboembolic complications of their underlying heart disease, 115 served as control. Approximately half of the patients in each group received aprotinin treatment during operation. MEASUREMENTS AND MAIN RESULTS: The international normalized ratio (INR) of the prothrombin time was preoperatively 2.4 (95% confidence interval [CI 0.95]: 2.3 to 2.6) in the warfarin group and 1.1 (CI 0.95: 1.0 to 1.1) in the control group (p < 0.05), and postoperatively 1.9 (CI 0.95: 1.8 to 2.1) (warfarin) and 1.5 (CI 0.95: 1.4 to 1.5) (control) (p < 0.05). The postoperative blood loss after 6 and 12 hours was 381 (CI 0.95: 329 to 434)/505 (CI 0.95: 439 to 571) mL (warfarin) compared with 472 (CI 0.95: 403 to 541)/612 (CI 0.95: 527 to 697) mL (control) (p < 0.05). This difference was blunted when the proteinase inhibitor aprotinin was used. Neither preoperative nor postoperative prothrombin time correlated with blood loss. Despite lower heparin consumption the activated coagulation time (ACT) during CPB was significantly prolonged in the warfarin group. CONCLUSIONS: Warfarin pretreatment does not lead to increased bleeding but may even have a beneficial anticoagulant effect that may lead to better preserved postoperative hemostasis and reduced blood loss.

Autotransfusion and hemoseparation in cardiac surgery. What can be saved in cardiac reoperations and operations of thoracic aortic aneurysms?

In 149 patients, scheduled for cardiac reoperations, repair of cyanotic heart disease or resection of aneurysms of the ascending or descending aorta, the effect of intraoperative hemoseparation was studied. The amount of autologous blood which was collected before, during, and after systemic heparinisation and processed to washed packed red cells was registered. Mean packed cell quantities gained intraoperatively were: 1275 (1006-2067) ml (descending aortic aneurysm), 1800 (1186-2500) ml (ascending aortic aneurysm), 1524 (1030-1801) ml (single valve rereplacement), 1896 (1398-2368) ml (double valve rereplacement), 946 (800-1050) ml (coronary artery reoperation), 1362 (922-1455) ml (cyanotic heart disease) and 1519 (1194-2066) ml (miscellaneous cardiac operations). In 35 patients more than 2000 ml and in 14 patients more than 3000 ml packed cells were harvested. Based on body weight, relatively more packed cells could be gained in patients with cyanotic heart disease (41 ml/kg) than in the other groups (21 ml/kg). In these young patients the application of a smaller centrifuge bowl (125 ml) can be helpful. These results demonstrate that cell saving by means of a cell separator with a special suction line and collecting system can help to reduce the donor blood requirement in cardiac operations, in which large intraoperative blood loss is anticipated.

Influence of high-dose aprotinin on anticoagulation, heparin requirement, and celite- and kaolin-activated clotting time in heparin-pretreated patients undergoing open-heart surgery. A double-blind, placebo-controlled study.

BACKGROUND: Aprotinin causes a prolongation of the celite-activated clotting time (CACT), but not of the kaolin-activated clotting time (KACT). Therefore, concern has been raised regarding the reliability of CACT to monitor anticoagulation in the presence of aprotinin. The current study was designed to test the efficacy of aprotinin to improve anticoagulation, and to investigate whether the prolongation of CACT reflects true anticoagulation or is an in vitro artifact. To elucidate this antithrombotic effect of aprotinin, this study was done in patients prone to reduced intraoperative heparin sensitivity. METHODS: In a prospective, randomized, double-blind clinical trial, 30 male patients scheduled for elective primary coronary revascularization and treated with heparin for at least 10 days preoperatively, received either high-dose aprotinin (group A) or placebo (group C). The CACT and KACT were determined, but only CACT was used to control anticoagulation with heparin. Parameters of coagulation that are indicators of thrombin generation and activity (F1+2 prothrombin fragments, thrombin-antithrombin III complex, and fibrin monomers), parameters of fibrinolysis (D-dimers), aprotinin, and heparin plasma concentrations were measured. Postoperative blood loss and allogeneic blood transfused were recorded. RESULTS: Total heparin administered was 36,200 units (95% confidence interval: 31,400-41,000; group C) compared with 27,700 (25,500-29,800) units (group A; P < 0.05). Hemostatic activation during cardiopulmonary bypass (CPB) was significantly reduced in group A compared with group C. After 60 min of CPB, all parameters were significantly different (P < 0.05) between the groups (group C vs. group A): F1+2 prothrombin fragments, 9.7 (8.9-11.7) ng/ml versus 7.5 (6.2-8.6) ng/ml; thrombin-anti-thrombin III complex (TAT), 53 (42-68) ng/ml versus 29 (23-38) ng/ml; and fibrin monomers, 23 (12-43) ng/ml versus 8 (3-17) ng/ml. Fibrinolysis was also attenuated; D-dimers at the end of operation were 656 (396-1,089) and 2,710 (1,811-4,055) ng/ml for groups A and C, respectively (P < 0.05). The CACT 5 min after the onset of CPB was 552 (485-627) versus 869 (793-955) s for groups C and A, respectively (P < 0.05), whereas the KACT showed no differences between the groups (569 [481-675] vs. 614 [541-697] s for groups C and A, respectively; P = NS). The 24-h blood loss was 1,496 (1,125-1,995) versus 597 (448-794) ml for groups C and A, respectively (P < 0.05). CONCLUSIONS: Aprotinin treatment in combination with heparin leads to less thrombin generation during CPB. Aprotinin has anticoagulant properties. Celite-activated ACT is reliable for monitoring anticoagulation in the presence of aprotinin, because the prolonged CACT in the aprotinin group reflects improved anticoagulation. Kaolin-activated ACT does not reflect this effect of aprotinin.

Reduction of homologous blood requirement in cardiac surgery by intraoperative aprotinin application--clinical experience in 152 cardiac surgical patients.

The protease inhibitor aprotinin interacts with plasmin and kallikrein, which are generated in cardiac surgery during cardiopulmonary bypass (CPB). The influence of high-dose aprotinin application (2 million kallikrein inactivator units given i.v. at the beginning of anaesthesia followed by a 500,000 KIU/h infusion throughout the operation and additional 2 millions KIU added to the priming of the oxygenator) on perioperative blood loss and donor blood requirement was studied in 152 adult cardiac surgical patients. This group was compared to 317 patients having cardiac surgery without the application of aprotinin. Aprotinin reduced the homologous blood requirement by 43% (1783 +/- 100 vs 1015 +/- 131 ml, p less than 0.05), while the reduction of postoperative blood loss was 29% (1070 +/- 43 vs 761 +/- 51 ml, p less than 0.05). Fortytwo percent of the aprotinin treated patients completed their hospital stay without having any donor blood transfusion compared to 18% in the group without aprotinin. The blood saving effect was even more pronounced in operations with prolonged perfusion times. Intra- and postoperative complications were equally distributed in both groups. The blood-saving effect of aprotinin may be due to a platelet-preserving effect and/or kallikrein inhibition during CPB. There were no clinically relevant side effects related to aprotinin observed. It is concluded that high dose aprotinin therapy reduces both postoperative blood loss and homologous blood requirement, and therefore the routine application of aprotinin during cardiac surgical procedures is to be recommended.