[The malignant tumor of the pulmonary artery; report of a case].

Primary sarcoma of the pulmonary artery is rare. Diagnosis is difficult and often delayed; pulmonary embolism is part of the differential diagnosis. We treated a 46-year-old woman with progressive dyspnea. Computed tomography showed a lesion occupying the main pulmonary artery and peripheral branches on both sides. The pulmonary artery tumor, resected under cardiopulmonary bypass, was diagnosed pathologically as intimal sarcoma. Two weeks after the operation, the patient was feeling well and discharged from our hospital. Although the prognosis of pulmonary artery sarcoma is poor, early diagnosis and resection may prolong survival.

[Quality of life of long-term survivors of surgically treated lung cancer].

Quality of life (QOL) of long-term survivors (more than 3 years after surgery) of primary non-small cell lung cancer was studied. QOL was analyzed using European Organization for Research and Treatment of Cancer Quality of Life Questionnaire, 30-Item version 3.0 (QLQ-C30) and Hospital Anxiety and Depression Scale (HADS). Sixty of 91 patients (66%) participated in this study 87 +/- 5 (38-172) months postoperatively. In QLQ-C30, calculated scores of physical (84.0 +/- 2.4), role (81.3 +/- 3.6), cognitive (79.7 +/- 2.6), emotional (86.8 +/- 1.9), and social (91.0 +/- 1.9) functioning, and global QOL (72.6 +/- 2.9) were obtained. Calculated HADS A (anxiety) was 3.3 +/- 0.3 and HADS D (depression) was 4.0 +/- 0.4. Postoperative follow-up duration was correlated with financial impact only. QOL of long-term survivors was influenced by gender histology, marital status, employment status, and academic carrier.

The Cox maze iii procedure: parallel normalization of sinus node dysfunction, improvement of atrial function, and recovery of the cardiac autonomic nervous system.

OBJECTIVE: The Cox maze III procedure includes isolation of the pulmonary veins and multiple incisions in both atria in what corresponds to partial autotransplantation and partial denervation of the heart. The aim of this prospective longitudinal study was to identify physiologic effects of reinnervation on changes in heart rate at rest and in response to various stimulations and on atrial function after the Cox maze III procedure. PATIENTS AND METHODS: Power spectral analysis of heart rate variability, exercise testing, 24-hour Holter monitoring, electrocardiography, and transthoracic and transesophageal echocardiography were performed in 30 adult patients after the combined Cox maze III procedure and mitral valve surgery (maze group). They were prospectively followed up at 1, 3, 6, and 12 months after the operation. The results were compared with those of 15 heart transplant recipients (transplant group) and normal probands (healthy adults, n = 12). RESULTS: The physiologic effects of denervation with no differences in cardiac autonomic activity between the groups were seen early after the operation. Later, evidence of autonomic reinnervation was observed only in the maze group but not in the transplant group. Inappropriate heart rate responses during physical exercise were clearly evident in both groups after 1 and 3 months, with progressive improvement seen between 6 and 12 months only in the maze group. Left atrial function after the Cox maze procedure improved parallel to the recovery of sinus node function. CONCLUSION: Progressive improvement of sinus node function and atrial contractions with significant functional normalization 1 year after the Cox maze procedure corresponded to functional reinnervation and recovery of the autonomic nervous system.

Influences of bilateral endoscopic transthoracic sympathicotomy on cardiac autonomic nervous activity.

OBJECTIVES: Endoscopic transthoracic sympathicotomy (ETS) is a minimal invasive procedure of thoracic sympathetic blockage. The purpose of this study was to evaluate cardiac autonomic nervous activity after ETS in order to confirm the reliability and safety of ETS. METHODS: A series of electrophysiological studies were performed before and 1 week after bilateral 2nd and 3rd thoracic sympathicotomy in 13 patients with primary palmar hyperhydrosis. Palmar perspiration was measured under sympathetic stress, and body surface mapping was recorded in a supine position. In the head-up tilt test of 0, 30, 60 and 90 degrees, corrected QT interval (QTc) and T wave amplitude (Twa) were assessed. The power spectral analysis of heart rate variability was processed to attain power values of the low-frequency (0.04-0.15 Hz), the high-frequency (0.15-0.40 Hz) and the low/high frequency ratio. RESULTS: In all patients, the perspiration response on the palm to sympathetic stimulation was completely inhibited after ETS. Isointegral mapping revealed that ETS altered electroactivity on the heart. In the head-up tilt study, R-R intervals significantly increased after the surgery in the head-up tilt positions (P < 0.05), although there was no significant difference in the supine position. There is no significant difference in QTc and Twa before and after the surgery, both in the supine and the head-up tilt positions. There was no significant difference in the LF or HF before and after surgery, either in the supine position or the head-up tilt positions. In the LF/HF, there was no significant difference before and after surgery in the supine position. However, the LF/HF in the head-up tilt positions was significantly decreased after surgery (P < 0.05). Sympathetic suppression of ETS was recognized more obviously under the steeper head-up tilt positions. CONCLUSIONS: The influences on the cardiac autonomic nerve system of the ETS of upper thoracic sympathetic nerve were seen to be of a lesser degree at rest. However, the response to sympathetic stimulation was suppressed after the surgery.

Transient sinus node dysfunction after the Cox-maze III procedure in patients with organic heart disease and chronic fixed atrial fibrillation.

OBJECTIVES: This prospective study examined types, frequency and time dependency of the electrophysiologic manifestation of the sinus node dysfunction after the Cox-maze III procedure--the technique of choice for the management of medically refractory atrial fibrillation-in patients with organic heart disease, chronic fixed atrial fibrillation and no preoperatively overt dysfunction of the sinus node. BACKGROUND: The original maze procedure was modified twice in order to reduce the high incidence of the sinus node inability to generate an appropriate sinus tachycardia in response to maximal exercise, and occasional left atrial dysfunction. Despite these modifications, postoperative disturbance of sinus node function can be frequently observed. METHODS: In 15 adult patients, standard electrocardiogram, 24-h Holter monitoring, power spectral analysis of heart variability, exercise testing, Valsalva maneuver and rapid positional changes were performed 3, 6 and 12 months after the Cox-maze III procedure and mitral valve surgery or closure of atrial septal defect. RESULTS: Electrocardiographic manifestations of sinus node dysfunction were identified in 12 patients at 3 months, in 6 patients at 6 months, and in 0 patients at 12 months after surgery. The heart rate response to exercise during the first 6 months was reduced in the maze group and became fully normal at 12 months. Power spectral analysis of heart rate variability showed very low power values at 1 month with inhibited cardiac autonomic activity and no response on sympathetic stress. A potential of recovery of cardiac autonomic activity was documented 12 months after surgery. CONCLUSIONS: The manifestations of sinus node dysfunction following the Cox-maze III procedure were time dependent and their frequency and intensity progressively decreased and disappeared within 12 months after surgery.

Coronary bypass flow during use of intraaortic balloon pumping and left ventricular assist device.

BACKGROUND: Intraaortic balloon pumping (IABP) and left ventricular assist device (LVAD) are used for left ventricular support when low cardiac output occurs after a coronary bypass operation for serious coronary artery disease. There are hemodynamic differences in blood flow in various kinds of coronary artery bypass grafts, caused by their inherent physiologic characteristics. The hemodynamic effects of left ventricular assistance with IABP and LVAD on blood flow through various coronary artery bypass grafts were investigated. METHODS: An ascending aorta-coronary bypass graft (ACB), an internal thoracic artery, and a descending aorta-coronary bypass graft were anastomosed to the left anterior descending coronary artery in a canine model. In this experimental model, the blood flow to the same coronary bed in the three types of grafts could be evaluated. Blood flow in the left anterior descending coronary artery through the three types of coronary bypass grafts was studied in this model during or in the absence of ventricular assistance. RESULTS: In the control study, the systolic blood flow did not differ among the three types of grafts, but the diastolic flow decreased in the following order: with the ACB, the internal thoracic artery, and the descending aorta-coronary bypass graft. The systolic flow during IABP and LVAD was similar to the control flows. Use of IABP increased the diastolic flow by 75.3%+/-12.4% of the control value in the ACB, 37.9%+/-25.0% in the internal thoracic artery, and 21.2%+/-11.4% in the descending aorta-coronary bypass graft. The LVAD increased the diastolic flow by 97.7%+/-18.7% of the control value in the ACB, 64.5%+/-25.7% in the internal thoracic artery, and 63.0%+/-27.9% in the descending aorta-coronary bypass graft. The diastolic blood flows in the left anterior descending coronary artery and the three types of grafts were significantly greater with IABP than the control values, and significantly greater with LVAD than with IABP and the control values. The degrees of increase of diastolic flows in the left anterior descending coronary artery and the ACB with IABP and LVAD were significantly greater than in the arterial grafts (p < 0.01). CONCLUSIONS: The diastolic flows in the internal thoracic artery and descending aorta-coronary bypass graft increased less than in the native left anterior descending coronary artery and ACB during left ventricular assistance, particularly with IABP. It is important for the selection of tactics for the management of catastrophic status after coronary bypass grafting to consider the hemodynamic characteristics of the graft.

[Surgical technique of endoscopic transthoracic sympathicotomy: axillary approach].

A total of 181 endoscopic transthoracic sympathicotomy were performed at our hospital from December, 1992 to March, 1997. After single-lumen endotracheal intubation for general anesthesia, the patient was placed in half sitting position. A small (1 cm) incision was made in the anterior axillary line through the third intercostal space and an apical pneumothorax was created by insufflation of 1.8 L of CO2 in the pleural cavity through a Surgineedle. A 24 Fr. urological transurethral electroresectoscope was introduced through the same incision. The sympathetic chain could be observed through parietal pleura riding on the costovertebral junctions. In palmar hyperhidrosis the second and third thoracic sympathetic ganglia were electrocoagulated. In axillary hyperhidrosis the forth ganglion was included. The lung was expanded by limiting expiration and sucking CO2. The operation was repeated on the other side. Endoscopic transthoracic sympathicotomy was an efficient, safe and low invasive surgical procedure for the treatment of palmar, axillary hyperhidrosis, Raynaud's disease and Buerger disease.

[Endoscopic transthoracic sympathectomy for angina pectoris: a case report].

We performed endoscopic transthoracic sympathicotomy (ETS) for angina pectoris in a 77-year-old female. She had multiple coronary disease of a history of failed percutaneous transluminal coronary angioplasty (PTCA). Bilateral ETS of Th2 to Th5 was carried out under general anesthesia without surgical complication, hemodynamic change and ECG change. Postoperatively she was free from angina and increased working capacity. ST depression on ECG was remarkably improved and the increase of heart rate and systolic blood pressure was suppressed on exercise test after a month of ETS. The effect of ETS to angina pectoris was suspected not to relieve anginal pain but also to reduce myocardial oxygen demand on exercise. We conclude that ETS is a safe, simple and low invasive procedure and it can be done in patients who are judged unsuitable for coronary artery bypass grafting (CABG) or PTCA.

Is internal thoracic artery grafting suitable for a moderately stenotic coronary artery?

Grafting an internal thoracic artery to a coronary artery with moderate stenosis remains controversial. Competitive flow from the native coronary artery has been proposed as the cause of distal narrowing and ultimate failure of the internal thoracic artery graft. We investigated intraoperative phasic blood flow in internal thoracic arteries grafted to coronary arteries with various degrees of stenosis and the influence of stenosis on postoperative angiographic findings. One hundred patients who underwent coronary artery bypass grafting of an internal thoracic artery to the left anterior descending coronary artery were divided into three groups according to degree of coronary stenosis. Group 1 included 39 patients who had 75% or less stenosis, group 2 included 34 patients with stenosis from 76% to 90%, and group 3 included 27 patients with stenosis greater than 90%. Mean flow and peak systolic flow of internal thoracic artery graft in group 1 were lower than those in group 2 (p < 0.01, p < 0.05). Peak diastolic flow in group 1 showed no difference from flows in groups 2 and 3. In eight patients in group 1, internal thoracic artery flow showed a predominant diastolic peak with characteristic systolic reversal as a result of competitive flow from the native coronary artery. Angiography at 1 month showed that the internal thoracic artery graft was patent in every case. Relative contributions of native coronary artery and internal thoracic artery flow to distal perfusion differed among the three groups (p < 0.001). In group 1, 15% of patients showed native-dominant flow, 62% showed balanced flow, and 23% showed internal thoracic artery-dependent flow. In group 2, 9% of patients showed native-dominant flow, 29% showed balanced flow, and 62% showed internal thoracic artery-dependent flow. In group 3, 96% of patients showed internal thoracic artery-dependent flow. String sign of the internal thoracic artery graft developed in only three patients; in two of these patients internal thoracic arteries were grafted to coronary arteries with stenosis of 50% or less and in the other patient there was competitive flow from a diagonal vein graft. Eleven of 13 internal thoracic arteries grafted to coronary arteries with stenosis of 50% or less did not show string sign. Competitive flow from a moderately stenotic coronary artery did not predispose the patient toward string sign of the internal thoracic artery graft in the presence of substantial diastolic internal thoracic artery flow. We conclude that internal thoracic artery grafting is acceptable for a moderately stenotic coronary artery.

Internal thoracic artery graft function during exercise assessed by transthoracic Doppler echography.

BACKGROUND: Noninvasive quantitative assessment of internal thoracic artery (ITA) graft function at rest and during exercise is important in patients who have undergone coronary artery bypass grafting. METHODS: Blood flow in the ITA graft was measured using transthoracic color Doppler echography before and after operation in 50 patients who underwent coronary artery grafting using an ITA to the left anterior descending artery. The patients were divided into three groups according to the degree of coronary stenosis and previous anterior myocardial infarction: Group 1 included 12 patients with severe (90% or more) coronary stenosis accompanied by anterior infarction. Group 2 included 26 patients with severe coronary stenosis without anterior infarction. Group 3 included 12 patients with moderate (75% or less) coronary stenosis without anterior infarction. Transthoracic echographic images of the ITA were obtained through the first intercostal space using a 7.5-MHz probe, and the diameter and cross-sectional area of the ITA were measured on B-mode imaging. Systolic, diastolic, and mean blood flow velocity and volume were measured by the Doppler method. RESULTS: Internal thoracic artery diameter increased significantly from 2.2 mm to 2.4 mm after operation. The ITA flow patterns in both flow velocity and volume changed from systolic-dominant to diastolic-dominant after operation. Postoperative ITA graft flow was 82 +/- 24 mL/min, 53 +/- 30 mL/min, and 31 +/- 15 mL/min (p < 0.01, group 1 versus 3; p < 0.05, group 1 versus 2) and percent diastolic fraction of ITA flow was 72%, 68%, and 62% (not significant) in groups 1, 2, and 3, respectively. Compared with intraoperative ITA flow, which was measured using an ultrasound transit-time flowmeter, postoperative ITA graft flow was increased in group 1, but not changed in group 2 or 3. The ITA graft flow was measured before and after exercise in 19 patients and was compared with ITA flow in 10 normal control subjects. The ITA graft flow increased significantly with exercise in all patients in the three groups. Percent diastolic fraction of ITA flow increased significantly with exercise in patients with severe coronary stenosis (groups 1 and 2), but decreased significantly in patients with moderate stenosis (group 3). CONCLUSIONS: Changes in native coronary artery and ITA graft may be predicted by assessing ITA flow pattern during exercise. Transthoracic color Doppler echography is a clinically useful noninvasive method of assessing ITA graft function at rest and during exercise.

Pressure characteristics in arterial grafts for coronary bypass surgery.

The haemodynamic properties of arterial grafts were studied by measuring the pressure waveform at the tip of the grafts in 28 patients who underwent coronary artery bypass surgery (CABG). The internal thoracic and gastroepiploic arteries were harvested as pedicles for CABG. Pressure wave of the ascending aorta and arterial grafts were simultaneously recorded with an electrocardiogram under stable haemodynamic conditions before cardiopulmonary bypass. Systolic, diastolic and mean pressures were measured, and mean systolic and diastolic pressures calculated for systolic and diastolic areas divided by time. The ascending aorta showed high sustained diastolic pressure that decreased gradually. Pressures in the internal thoracic and gastroepiploic artery grafts had narrow contours and decreased rapidly. Pressure waveforms in the internal thoracic and gastroepiploic artery grafts had a notch between the systolic and diastolic contours. There was no difference in systolic pressure between the ascending aorta and internal thoracic and gastroepiploic artery grafts. Diastolic pressures were 64(9), 55(7), and 51(6) mmHg in the ascending aorta and internal thoracic and gastroepiploic artery, respectively. Mean(s.d.) pressures were 75(9), 65(9) and 59(7) mmHg in the ascending aorta and internal thoracic and gastroepiploic artery grafts, respectively. Diastolic and mean pressures in the internal thoracic artery grafts were significantly lower than in the ascending aorta but significantly higher than in the gastroepiploic artery grafts. The mean(s.d.) calculated diastolic pressure in the internal thoracic artery grafts was significantly lower than in the ascending aorta but significantly higher than in the gastroepiploic artery grafts. The inferior capacity of flow through the arterial grafts may be mainly attributable to reduced diastolic pressure, which is caused by anatomical characteristics.(ABSTRACT TRUNCATED AT 250 WORDS)

The effects on blood flows of coronary artery by-pass grafts during intra-aortic balloon pumping.

The internal thoracic artery (ITA), as well as aorto-coronary by-pass grafts, has been used for widely coronary artery by-pass grafting. Intra-aortic balloon pumping (IABP) is the first choice for left ventricular support when low output syndrome occurs during coronary artery by-pass surgery. However, the effect of diastolic augmentation by IABP may vary to the type of grafts. Graft flow with and without IABP support were measured in six patients undergoing elective coronary artery bypass surgery requiring IABP at Kanazawa National Hospital. The patients ranged in age from 59 to 67 years, with a mean age of 63 years, and included one woman and five men. In all cases, the left ITA was dissected from the thoracic wall as pedicle, and anastomosed in situ to the left anterior descending artery. Saphenous vein grafts (SVGs) were used for aortocoronary by-pass to the obtuse marginal branches, the first diagonal branches, the left circumflex branches, and/or the right coronary artery. Blood flow in 6 ITAs, 11 SVGs to the left coronary artery systems, and three SVGs to the right coronary artery was measured by ultrasound transit-time flowmeter simultaneously with the electrocardiogram. Blood flows in ITA grafts and SVGs were measured during IABP assist and unassisting under hemodynamically stable conditions after discontinuing cardiopulmonary by-pass. The systolic and diastolic flows of each graft were measured using the peak of the R wave and the end of T wave on the electrocardiogram as the references for systole. Systolic flow during IABP were similar to unassisted flow in both ITA and SVGs.(ABSTRACT TRUNCATED AT 250 WORDS)

[Extended tricuspid valve excision for active infective endocarditis associated with ventricular septal defect].

We report a patient of ventricular septal defect associated with a vegetations on the tricuspid valve and a perforation of the aortic cusp caused by infective endocarditis. Antibiotics could not relieve the high fever of this patient, and disseminated intravascular coagulation caused by sepsis and two-sided heart failure developed. She underwent extended tricuspid valve excision, aortic valve replacement and VSD closure during the active stage. Post-operative antibiotic therapy was continued intravenously for 6 weeks, and orally for 3 more weeks. Although post-operative right ventriculography indicated tricuspid regurgitation and right atrium enlargement, pressure study of the right side of the heart revealed normal hemodynamics.

[Effect of aprotinin on blood loss reduction after extracorporeal circulation].

High-dose aprotinin has been reported to reduce blood loss after extracorporeal circulation (ECC). However, the hemostatic mechanism of aprotinin remains unknown. We administered aprotinin to 25 patients during coronary artery bypass surgery and examined the blood loss in comparison with that in a control group of 25 patients. On the basis of an experimental study on the effects of aprotinin, 30,000 KIU/kg of aprotinin was infused as the initial ECC dose and 7,500 KIU/kg/h was continuously administered as the maintenance dose from the beginning to the end of ECC. Aprotinin was not used before ECC. Serial blood samples were collected during and after the operation in both groups to examine various coagulation and fibrinolysis system parameters. Blood loss during and 6 hours after the operation and the total blood requirement were significantly lower in the aprotinin group than in the control. There was no difference between the two groups in terms of hemoglobin, platelet count, ACT, and thrombin-antithrombin III complex level. The aprotinin group showed a significantly higher level of alpha 2 (total) plasmin inhibitor and a significantly lower level of plasmin-alpha 2 plasmin inhibitor complex and D-dimer during ECC. These findings indicated that although the coagulation system function was accelerated during ECC, the fibrinolysis function system was suppressed by the administration of aprotinin, which resulted in a reduction of blood loss.

Physiologic characteristics of coronary artery bypass grafts.

To investigate the hemodynamic characteristics of arterial grafts for coronary artery bypass grafting, we measured phasic pressure and flow patterns in three types of grafts in a canine model (n = 18). A graft from the ascending aorta (AAG), a graft from the descending aorta at the first lumbar level (DAG), analogous to a right gastroepiploic artery, and an internal thoracic artery (ITA) were anastomosed to each other. The composite graft was anastomosed to the left anterior descending coronary artery, and then the left anterior descending coronary artery was ligated. Before grafting, the AAG showed high sustained diastolic pressure, but the ITA and DAG showed rapid fall of diastolic pressures. Mean diastolic pressures were 83 +/- 2, 72 +/- 3, and 57 +/- 2 mm Hg in the AAG, ITA, and DAG (p < 0.05). Free flow in the AAG was markedly greater than in the ITA or the DAG. After grafting to the left anterior descending coronary artery, no changes were observed in diastolic pressures compared with the pregrafting values. Total blood flows were 72 +/- 6, 80 +/- 7, 57 +/- 7, and 44 +/- 6 mL/min in the left anterior descending coronary artery, AAG, ITA, and DAG, respectively. There were no differences in systolic graft flow between the three types of grafts. Diastolic blood flow in the ITA (29 +/- 4 mL/min) and DAG (18 +/- 3 mL/min) was smaller than in the AAG (48 +/- 4 mL/min) (p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Flow capacities of arterial grafts for coronary artery bypass grafting.

The flow capacities of arterial and saphenous vein grafts in 100 patients who had coronary artery bypass grafting were compared under exercise conditions by continuous ventricular function monitoring, which records serial beat-to-beat radionuclide data and calculates left ventricular ejection fractions every 20 seconds. Ejection fraction profiles during graded bicycle exercise were divided into four types. In type A, the ejection fraction continued to increase. In type B, the ejection fraction initially increased, but decreased during the late exercise stage. In type C, the ejection fraction did not change. In type D, the ejection fraction continued to decrease throughout exercise. A decrease in ejection fraction, observed in type B or D, is an early indicator of myocardial ischemia. Before operation, 10 patients showed type A, 30 type B, 11 type C, and 49 type D responses. After operation, 68 patients showed type A, 21 type B, and 11 type C responses. Patients were divided into three groups according the type of bypass graft. Group 1 included 21 patients with two arterial grafts and vein grafts; group 2, 61 patients with an internal thoracic artery graft and vein grafts; group 3, 18 patients with only vein grafts. All of the grafts were patent on angiography. Eight patients (38%) in group 1 and 13 (21%) in group 2 showed a postoperative type B response, but none of the patients in group 3 had a postoperative type B response (p < 0.02). Seven of 8 patients in group 1 with postoperative type B responses had only arterial grafts to the left-side coronary arteries.(ABSTRACT TRUNCATED AT 250 WORDS)

[Endoscopic elecrocautery of the thoracic sympathetic chain: a minimal invasive surgical treatment].

The thoracic sympathectomy was performed with standard laparoscopic and urologic equipment. After intubation, the patient was placed in a half sitting position. A Surgineedle was introduced into the pleural cavity through a 1 cm incision at the intercostal space between the first and second rib. An apical pneumothorax was created by insufflation of two litres of CO2. A 24 ch. urological trocar was inserted through the same incision, then the electroresectoscope was introduced into the pleural cavity. The sympathetic chain could be observed through parietal pleura riding on the costovertebral junctions. These areas were electrocoagulated. The lung was expanded by limiting expiration and sucking CO2. A postoperative chest X-ray was done to check no pneumothorax. This method was a simple and safe surgery, which was available for bilateral sympathectomy.

Effect of low-dose aprotinin on coagulation and fibrinolysis in cardiopulmonary bypass.

To study the effect of low-dose aprotinin on hemostasis in patients undergoing cardiopulmonary bypass (CPB) for coronary artery bypass operations and to elucidate the mechanism of aprotinin action, we randomized 14 of 27 patients to receive 30,000 KIU/kg aprotinin in the CPB priming volume and 7,500 KIU/kg aprotinin intravenously each hour during CPB (1 patient was excluded from the aprotinin group because of protamine shock). Intraoperative and postoperative blood loss was significantly reduced in the aprotinin group. Antithrombin III level was significantly decreased, and the levels of thrombin-antithrombin III complexes were significantly increased during CPB in both groups, indicating activation of the clotting system. The marked increase in fibrin(ogen) degradation products during CPB in the control group, indicating enhanced fibrinolytic activity, was significantly reduced in the aprotinin group. alpha 2-Plasmin inhibitor was significantly reduced during CPB in the control group. The marked increase in alpha 2-plasmin inhibitor-plasmin complexes in the control group, indicating plasmin activity, was significantly reduced in the aprotinin group. A marked decrease in the platelet count was observed during CPB similarly in both groups. These findings demonstrated that low-dose aprotinin administration was effective in reducing intraoperative and postoperative blood loss and that activation of the clotting system during CPB was not followed by hyperfibrinolysis in aprotinin-treated patients. The improved hemostasis is mainly attributable to the prevention of hyperfibrinolysis during CPB.