Reduced complement activation with heparin-coated oxygenator and tubings in coronary bypass operations.

Complement activation after cardiopulmonary bypass is correlated with postoperative organ dysfunction. Heparin coating of the entire blood-contact surface of the cardiopulmonary bypass circuit has proved to reduce complement activation in vitro. A membrane oxygenator and tubing setup coated with functionally active heparin was compared with an uncoated, otherwise identical setup in 20 patients undergoing routine coronary bypass operations. The concentrations of C3 activation products and the terminal complement complex were measured in sensitive and specific enzyme immunoassays. Peak concentrations of C3 activation products were 90.1 (74.7 to 107.4) AU/ml (medians and 95% confidence intervals) and 52.4 (35.7 to 76.4) AU/ml with the uncoated and coated setups, respectively (p = 0.02). The corresponding concentrations of the terminal complement complex were 26.2 (20.1 to 37.5) AU/ml and 13.7 (11.1 to 25.1) AU/ml (p = 0.03). Blood loss from the mediastinal drains during the first 12 postoperative hours was 533 (416 to 975) ml in patients treated with the uncoated setup and 388 (313 to 579) ml in the coated treatment group (p = 0.06) and was significantly correlated with peak concentrations of the terminal complement complex (p = 0.01). There were no differences in neutrophil counts nor platelet numbers between the treatment groups. The approximate 45% reduction in complement activation with the heparin-coated cardiopulmonary bypass device indicates a substantial improvement of biocompatibility.     

Time for new concepts about measurement of complement activation by cardiopulmonary bypass?

Fifty-one patients admitted for routine coronary bypass operations were randomized to cardiopulmonary bypass with a membrane oxygenator (Capiox) or a bubbler (Polystan or William Harvey). Complement activation was measured using enzyme immunoassays for concentrations of C3 activation products and the terminal complement complex. From 5.8 to 8.1 arbitrary units (AU)/mL (medians), the plasma concentrations of C3 activation products increased by 119.9 AU/mL (Capiox), 124.6 AU/mL (Polystan), and 79.5 AU/mL (William Harvey) to a peak at closure of the sternum (not significant when related to baseline concentrations). The increase in C3 activation products and baseline C3 activation were linearly correlated (R2 = 0.30; p less than 0.0001). From 5.5 to 6.1 AU/mL, the plasma terminal complement complex concentrations increased by 45.2 AU/mL (Capiox), 15.4 AU/mL (Polystan), and 17.4 AU/mL (William Harvey) to a peak before termination of cardiopulmonary bypass. Maximal terminal (C5-C9) activation was significantly higher in the membrane oxygenator group (p less than 0.0001) and showed no relationship to C3 activation. Measurement of C3 activation only gives no information about C5-C9 activation. At present, terminal complement complex quantitation is probably the best index of C5-C9 activation during cardiopulmonary bypass.     

Changes in Platelet, Granulocyte, and Complement Activation During Cardiopulmonary Bypass Using Heparin-coated Equipment

Abstract: The effects of heparin-coated cardiopulmonary bypass (CPB) systems on platelet, granulocyte, and complement activation were investigated during cardiopulmonary bypass. Thirty patients underwent coronary artery bypass surgery with a heparin-coated (Carmeda Bio-Active Surface, CBAS, Medtronic, U.S.A.) CPB system (HC group, n = 10), a heparin-coated oxygenator and uncoated CPB circuit (HO group, n = 10), or an uncoated system (UC group, n = 10). In the HO group, plasma C3a (1667 ± 632 ng/ml) and C4a (1088 ± 319 ng/ml) concentrations were significantly (p < 0.05) lower than in the UC group (2846 ± 1045 ng/ml and 1494 ± 480 ng/ml, respectively) 10 min after the administration of protamine, but there were no significant differences in the platelet or granulocyte counts. In the HC group, granulocyte elastase concentrations 120 min after the onset of CPB (365 ± 177 μg/L) and 10 min after the administration of protamine (676 ± 314 μg/L) were significantly (p < 0.05) lower than in the other 2 groups (820 ± 341 and 893 ± 303 μg/L and 1365 ± 595 and 1,258 ± 622 μg/L). In addition, the increase in the plasma C3a concentration in the HC group 60 (p < 0.05) and 120 min after the onset of CPB (p < 0.05) was significantly less than in the other 2 groups. The C3a and C4a concentrations 10 min after the administration of protamine were significantly (p < 0.005 and p < 0.05) less in the HC group than in the UC group. Platelet counts 10 min after the administration of protamine were significantly higher (p < 0.05) and plasma β-throm-boglobulin concentrations during CPB were significantly lower in the HC group than in the other 2 groups 5 (p < 0.05), 60, and 120 min (p < 0.005) after the onset of CPB. Postoperative blood loss during the first 12 h in the HC group was significantly (p < 0.05) less than that in the UC group. The heparin-coated oxygenator and uncoated CPB circuit reduced complement activation but demonstrated no significant effects on the platelet and granulocyte systems. However, the heparin-coated CPB circuit (with all components making blood contact) reduced platelet, granulocyte, and complement activation and significantly reduced postoperative blood loss. Therefore, heparin coating of CPB systems improves biocompatibility.     

Complement activation with bubble and membrane oxygenators in aortocoronary bypass grafting

Thirty-three patients admitted for coronary bypass grafting were randomized to cardiopulmonary bypass with a bubble oxygenator (Cobe or Polystan) or a membrane oxygenator (SciMed). Plasma concentrations of C3 activation products and the terminal complement complex were measured using enzyme immunoassays. Both variables increased almost linearly after onset of cardiopulmonary bypass, with maximal concentrations at closure of the sternum. From a baseline of 7.5 to 12.0 arbitrary units (AU)/mL (medians), the concentrations of C3 activation products increased by 117.5 AU/mL (Cobe), 120.5 AU/mL (Polystan), and 213.3 AU/mL (SciMed). The increase in the membrane group was significantly higher than in the two bubble oxygenator groups (p less than 0.01). From a baseline of 0.9 to 1.3 AU/mL, the concentrations of terminal complement complex increased by 5.4 AU/mL (Cobe), 6.6 AU/mL (Polystan), and 7.7 AU/mL (SciMed) (differences not significant). The higher C3 activation caused by the membrane oxygenator may be explained by differences in flow profile and surface area in contact with blood. The study cannot confirm the general assumption that membrane oxygenators lead to lower complement activation than do bubble oxygenators.     

Complement activation and increased systemic and pulmonary vascular resistance indices during infusion of postoperatively drained untreated blood

In nine healthy young patients, operated on for thoracic scoliosis, a pulmonary artery catheter was inserted for the study of haemodynamic variables and blood sampling during autologous transfusion of postoperatively drained blood. At 1-3 h after wound closure, 10 ml kg/body weight of drained untreated blood from the wound was collected and recirculated over a l-h period. The concentration of the complement activation product, C3bc, increased from a mean of 5.4 (SD 1.5) AU ml-1 before infusion to 11.1 (3.9) AU ml-1 during infusion and then returned to 7.8 (2.8) AU ml-1 after infusion. The concentration of the terminal complement complex (TCC) increased from 0.5 (0.2) to 1.3 (0.5) AU ml-1 and was reduced to 0.7 (0.3) AU ml-1 after infusion. Only TCC exceeded the reference values which are 14 AU ml-1 for C3bc and 1.0 AU ml-1 for TCC. Pulmonary vascular resistance index concomitantly increased from a mean of 130 (SD 52) to 195 (88) dyn s cm-5 m-2 and was reduced to 170 (86) dyn s cm-5 m-2 after infusion. Systemic vascular resistance index increased from a mean of 1238 (SD 403) to 1349 (473) dyn s cm-5 m-2 and returned to 1196 (401) dyn s cm-5 m-2 after infusion. White blood cell count (WCC) increased from 14.4 (4.3) x 10(9) litre-1 before infusion to 17.8 (7.2) x 10(9) litre-1 during and after infusion. No change in platelet count during infusion was observed. There were no differences in WCC or platelet count between mixed venous or peripheral arterial blood. Pulmonary and systemic vascular resistance indices may be influenced by activated complement in drained untreated blood when it is recirculated.      

Generation of platelet-derived microparticles in patients undergoing cardiac surgery is not affected by complement activation

OBJECTIVE: The mechanisms causing the presence of platelet-derived microparticles in the circulation are unknown. In vitro platelets release platelet-derived microparticles in response to complement activation. This study evaluates the relationship between complement activation and levels of circulating platelet-derived microparticles in patients undergoing cardiac surgery. METHODS: Prospectively, 71 patients were included who underwent elective coronary artery bypass grafting with cardiopulmonary bypass. The patients were randomly allocated to one of the 3 groups: uncoated oxygenator, UnModified Surface (n = 25) or oxygenator coated with either BioPassive Surface (n = 25) or BioActive Surface (n = 21). Platelet-derived microparticles and terminal complement complexes were determined before bypass and after induction of anesthesia, 15 minutes after the start of cardiopulmonary bypass, at the end of cardiopulmonary bypass, and 30 minutes after administration of protamine sulfate. RESULTS: Demographic and cardiopulmonary bypass data were similar for the 3 groups. At the end of cardiopulmonary bypass, platelet-derived microparticle numbers were decreased in all 3 groups. No significant differences were observed among the groups at any sampling point. At the end of cardiopulmonary bypass, terminal complement complex concentrations were increased in all groups (P <.001), and significant differences among the groups were present (P =.002). CONCLUSIONS: Despite significant complement activation, no increase in numbers of circulating platelet-derived microparticles was found in the systemic blood of patients undergoing cardiac surgery with cardiopulmonary bypass. Thus complement activation in vivo does not necessarily affect generation of platelet-derived microparticles.     

Performance characteristics of hemofilters with heparin surface coating: an experimental study

Heparin surface coated hemofilters and tubing sets were evaluated in comparison to identical but uncoated controls in 8 bovine experiments (74+/-6 kg). No heparin was given (neither systemically nor in the priming fluid). The hemofilters were primed with one liter of Ringer's lactate in both groups and the maximal filter performance (arterial line pressure 300 mmHg; transmembrane pressure (TMP) 500 mmHg) was measured over 6 hours or until filter occlusion. All coated and one control filter remained functional during the scheduled 6 hours. The mean filter patency was 360+/-0 minutes for coated versus 210+/-99 minutes for uncoated (p less than 0.01). Mean blood flow at 1 hour and 6 hours was 675+/-114 and 580+/-96 ml/min for coated versus 432+/-183 and 25+/-43 for uncoated (NS; p less than 0.01). Mean filter output during the 6th hour and total filter output over 6 hours was 4225+/-998 ml and 21779+/-4273 for coated versus 400+/-692 and 7717+/-9757 for uncoated (p less than 0.01; p<0.01). Mean lactatedehydrogenase (LDH) levels before and 30 minutes after hemofiltration were 1855+/-411 IU and 2007+/-635 for coated versus 2160+/-411 and 1945+/-500 for uncoated (NS; NS). The heparin coated hemofilters demonstrated improved thromboresistance resulting in superior filter performance. There was no evidence of increased blood trauma.     

Biocompatibility of Heparin-Coated Membrane Oxygenator During Cardiopulmonary Bypass

Abstract: The biocompatibility of the cardiopulmonary bypass (CPB) circuit, in which an oxygenator is solely heparinized, was assessed by systemic inflammatory reactions as an indicator during CPB. Fourteen patients, 11 males and 3 females, underwent coronary artery bypass surgery and were randomly divided into 2 groups of 7 patients each. For the heparin–coated oxygenator group (Group H), a heparin–coated membrane oxygenator was used in the CPB circuit, and in the control (Group C) an uncoated membrane oxygenator was employed. Systemic inflammatory reactions, such as platelet activation, prostaglandin production, complement activation, and activated granulocyte released substance, were measured prior to, during, and 6 h after CPB. The number of platelets decreased after protamine administration in both groups (14. 5 ±4. 7 times 10⁴/μl in Group H and 13. 8 ± 8. 7 times 10⁴/μd in Group C) and returned to baseline levels in Group H while it remained decreased in Group C at 6 h after CPB. The platelet factor 4 level was significantly lower in Group H (181 ± 40 ng/ml) than in Group C (297 ±131 ng/ml) after protamine administration. Thromboxane–B₂ (TXB₂) rose during CPB in both groups; however, there were significantly different levels of TXB₂ between the 2 groups at 60 min after CPB (293±258 pg/ml in Group H versus 408 ± 120 pg/ml in Group C) and after protamine administration (259 ± 122 pg/ml in Group H versus 709 ± 418 pg/ml in Group C). Plasma concentrations of granulocyte elastase were significantly lower in Group H at 30, 60 and 90 min, immediately after, and post–CPB than those of Group C. Although the oxygenator was solely heparinized in the CPB circuit, it was sufficiently effective to reduce inflammatory reactions during coronary artery bypass operation, and the heparin–coated surface seems to be more endothelium–like.     

Biocompatibility of Trillium Biopassive Surface-coated oxygenator versus uncoated oxygenator during cardiopulmonary bypass.

OBJECTIVE: To determine if the Trillium Biopassive Surface (Medtronic Cardiopulmonary, Minneapolis, MN) coating added to the cardiopulmonary bypass oxygenator reduces inflammatory mediators, blood loss, and transfusion requirements. DESIGN: Prospective, randomized, and blinded human trial. SETTING: Tertiary care academic medical center. PARTICIPANTS: Thirty adult patients undergoing elective coronary artery bypass graft surgery. INTERVENTIONS: Patients received visually identical coated or uncoated oxygenators. MEASUREMENTS AND MAIN RESULTS: Hemoglobin, hematocrit, leukocyte count, platelet count, terminal complement complex, complement activation, myeloperoxidase, beta-thromboglobulin, prothrombin fragment 1.2, plasmin-antiplasmin, heparin concentration, activated coagulation time, and fibrinogen concentration were measured. Blood loss and blood product usage were recorded. In both groups, there were significant inflammatory alterations with the initiation of cardiopulmonary bypass. In the postprotamine samples, the coated oxygenator group had small but significant increases in hemoglobin, hematocrit, and leukocyte count. There were no differences in inflammatory mediators, blood loss, or transfusion requirements between the coated and uncoated groups. CONCLUSION: This human trial of Trillium Biopassive Surface-coated oxygenators did not show clinical benefits or clinically important biochemical results.     

Use of heparin-coated cardiopulmonary bypass circuit with low-dose heparin reduces postoperative bleeding.

Postoperative bleeding was examined in patients undergoing cardiopulmonary bypass with a heparin-coated circuit and low-dose heparin. Out of 150 patients who underwent cardiopulmonary bypass for longer than 90 minutes, 74 received a standard dose (300 IU/kg) of heparin with an uncoated circuit (group C) and 76 received a low-dose (150 IU/kg) of heparin with a heparin-coated circuit (group H). The coagulation and fibrinolytic systems were investigated in 24 patients. Re-opening of the chest due to bleeding was performed in 5 patients in group C (7%), but none of the patients in group H (p=0. 03). The median of blood loss in the first 12 hours after surgery was 292 ml in group C, and 216 ml in group H (p=0.006). There were no significant differences in the peak thrombin-antithrombin complex concentration between the two groups. The plasmin-alpha 2 plasmin inhibitor complex concentrations after protamine administration were 1.9 ng/ml (median) in group C and 1.1 ng/ml in group H (p=0.002). The use of heparin-coated cardiopulmonary bypass circuits with low-dose heparin suppressed the activation of fibrinolysis. This may explain the reduction in postoperative bleeding.     

Heparin-coated cardiopulmonary bypass equipment. I. Biocompatibility markers and development of complications in a high-risk population

OBJECTIVES: 1. To study possible clinical benefits of heparin-coated cardiopulmonary bypass in patients with a broad range of preoperative risk factors. 2. To evaluate the correlation between the terminal complement complex and clinical outcome. 3. To identify clinical predictors of complement activation and correlates of granulocyte activation during cardiac surgery. METHODS: Blood samples from adults undergoing elective cardiac surgery with Duraflo II heparin-coated (n = 81) or uncoated (n = 75) cardiopulmonary bypass sets (Duraflo coating surface; Baxter International, Inc, Deerfield, Ill) were analyzed for activation of complement (C3 activation products, terminal complement complex), granulocytes (myeloperoxidase, lactoferrin), and platelets (beta-thromboglobulin) by enzyme immunoassays. Preoperative risk was assessed by means of the "Higgins' score." Complications (cardiac, renal, pulmonary, gastrointestinal, and central nervous system dysfunction, infections, death) were registered prospectively. Data were analyzed by analysis of variance, logistic regression, and linear regression. RESULTS AND CONCLUSIONS: Sixty-seven percent of the patients had predefined risk factors. Complications developed in 53 patients (34%), equivalently with and without heparin-coated bypass sets (P =. 44-.82), despite a significant reduction in complement and granulocyte activation by heparin coating. No clear-cut relationship between the terminal complement complex and outcome was found, even if it was significant in the models for renal and central nervous system dysfunction and infections (P =.006). The Higgins' score was significantly related to complement activation (P <.05). Approximately 50% of the variation in granulocyte activation was explained by complement (P 相似文献   

Reduced Granulocyte Activation with a Heparin–Coated Device in an In Vitro Model of Cardiopulmonary Bypass

Granulocyte activation during cardiopulmonary bypass (CPB), resulting in degranulation, may have adverse effects. Fresh whole human blood and priming solution was circulated through oxygenator/tubing sets coated with functional heparin (n = 7) and through uncoated sets (n = 7) in model CPB. Plasma concentrations of the primary granule protein myeloperoxidase (MPO) and the secondary granule protein lactoferrin (LF) were measured in radioimmunoassays, and the neutrophils were counted. After 120 min, seven to nine times baseline concentrations of LF (p less than 0.0001) were observed with both devices. Increases of MPO were also significant, but significantly larger (p less than 0.01) with the uncoated devices. There was an equivalent reduction in neutrophil numbers in both groups. MPO did not bind to heparin-coated Sephadex particles in gel chromatography. Thus, the heparin coating most likely prevented the release of potentially harmful primary granule proteins, indicating improved biocompatibility. Adhesion of neutrophils and exocytosis of LF, which may be involved in adhesion, were unaffected.     

Hyaluronan based heparin free coated open and closed extracorporeal circuits for high risk coronary revascularization

This prospective randomized study compares the inflammatory response and fibrinolytic activation of fully coated/uncoated and open/closed extracorporeal circuits (ECC) in high risk patients. Over a 2-month period, 48 patients with EuroSCOREs 6 or greater undergoing coronary revascularization were prospectively randomized to one of the four perfusion protocols: Group 1: Closed and totally hyaluronan based heparin free coated (Vision HFO-GBS-HF, Gish Biomedical, Rancho Santa Margarita, CA) ECC with a soft-shell coated venous reservoir (SVR11S2-HFC, Gish Biomedical) and a hard-shell cardiotomy (CAPVRF44, Gish Biomedical) (n = 12); Group 2: Closed and totally uncoated identical ECC with soft-shell uncoated venous reservoir and a hard-shell cardiotomy (n = 12); Group 3: Open, totally hyaluronan based heparin free coated ECC (n = 12); and Group 4: Control-open, uncoated ECC (n = 12). Blood samples were collected at T1: Baseline; T2: 15 minutes after cardiopulmonary bypass (CPB) initiation; T3: before cessation of CPB; T4: 15 minutes after protamine reversal, and T5: in the intensive care unit. Serum IL-6 levels were significantly lower at T2 in all study groups, at T3 for coated groups, and T4 for closed+coated group (p < .05 versus control). Creatine kinase M-band (MB) levels in coronary sinus blood demonstrated well preserved myocardium after CPB in both coated groups versus Control (p < .05). Neutrophil CD11b/CD18 levels were significantly lower for all study groups versus control at T2, for both coated groups at T3 and only for closed + coated group at T4 (p < .05). Postoperative hemorrhage (mL) was 510 +/- 40 in closed + coated and 536 +/- 40 in open + coated groups (control: 784 +/- 48, p < .05). No significant differences in thrombin-antithrombin complex and free plasma hemoglobin were observed. Desorbed protein amount on ECC (mg/dL) was 1.7 +/- .01 in closed+coated, 2.01 +/- .01 in open+coated, and 3.3 +/- .015 in control groups (p < or = .05). Use of a closed and completely heparin free coated ECC may reduce neutrophil degradation, cytokine release characterized by improved clinical outcomes including reduced blood loss, reduced requirement for inotropes, and reduced atrial fibrillation.     

Evidence for complement activation by protamine-heparin interaction after cardiopulmonary bypass

Complement activation by the alternate pathway has been implicated in the pathophysiology of cardiopulmonary bypass (CPB), and laboratory studies suggest that the complement cascade may be activated by the protamine-heparin complex. To determine if the administration of protamine to patients receiving heparin activates complement, we studied 100 patients undergoing CPB by assaying levels of C3a and C4a (classic pathway) at regular intervals before and after protamine administration. In group I (90 patients), protamine was given at the usual interval (median 5 minutes) after CPB. In group II (10 patients), protamine was withheld until skin closure (median 45 minutes) after CPB. Results demonstrated that C4a was not activated during CPB in either group. After CPB, the C4a level in group I was 459 ng/dl and increased to 1047 ng/dl 10 minutes after protamine administration (p less than 0.001). In group II, the C4a level was 484 ng/dl at the end of CPB and 354 ng/dl 15 minutes later, which corresponds to the value immediately after protamine administration in group I. The delayed administration of protamine in group II caused a significant increase in C4a at the time of skin closure (1090 ng/dl; p less than 0.001). Corresponding results from C3a analysis before and after protamine administration confirmed the activation of complement cascade. Our study provides the first clinical evidence that the protamine-heparin complex activates complement via the classic (C4a) pathway. The hemodynamic effects of protamine after CPB may be related to complement activation.     

In vivo evaluation of a phosphorylcholine coated cardiopulmonary bypass circuit

A complete phosphorylcholine coated cardiopulmonary bypass circuit, including the Dideco D901 oxygenator, was tested for gas transfer, blood path resistance, and biocompatibility in a standardized setting. Blood compatibility was tested by measuring complement and platelet activation. Three dogs (mean body weight 28 +/- 3 kg) were placed on cardiopulmonary bypass at a flow rate of 600 mL/min during 6 hours. The animals were weaned from cardiopulmonary bypass and sacrificed electively after 7 days. Oxygen and carbon dioxide transfer were 26.6 +/- 2.4 mL/min and 33.0 +/- 1.9 mL/min, respectively. Mean pressure drop across the oxygenator was 52.6 +/- 0.2 mmHg. The respective baseline values for thromboxane B2, prostaglandin E2 and platelet factor 4 were 1817 +/- 283 pg/mL, 12783 +/- 2109 pg/mL, and 0.35 +/- 0.08 IU/mL. Thromboxane B2 and prostaglandin E2 increased slightly to 2881 +/- 868 pg/mL and 18083 +/- 3144 pg/mL at 30 minutes of bypass, whereas platelet factor 4 values remained stable curing the procedure. Concentrations of complement split products C5a were only mildly increased. After use scanning electron microscopy was performed on the inner housing, heat exchanger, and outer surface of the hollow fibers. No thrombi nor organized cellular deposits were found on any of the components. Phosphorylcholine coating of CPB seems to be very promising regarding platelet activation and complement activation.     

Endocrine profiles and gonadotropin response to Gn-RH of men with testicular cancer

PURPOSE: To investigate the function of the hypothalamic-pituitary-testicular axis in testicular germ cell tumors, we evaluated gonadotropin responses to gonadotropin-releasing hormone (Gn-RH), semen quality, and serum levels of sex steroid hormones in patients with testicular cancer. PATIENTS AND METHODS: Basal serum levels of luteinizing hormone (LH), follicle stimulating hormone (FSH), and human chorionic gonadotropin-beta (hCG-beta) were measured before and after high orchiectomy in 20 patients with germ cell tumors of the testicle (9 with seminoma and 11 with nonseminomatous tumor). Semen quality and basal serum levels of testosterone, free testosterone, and estradiol were measured before orchiectomy. The Gn-RH test was performed before orchiectomy in all patients and after orchiectomy in patients without detectable gonadotropin levels in pre-operative serum samples. Gonadotropin levels were measured at 0, 30, 60, 90, and 120 minutes after intravenous injection of 100 micrograms of luteinizing hormone-releasing hormone (LH-RH). RESULTS: Serum gonadotropin concentrations were not detectable in 6 of 8 (75%) men with hCG positive tumors or in 4 of 12 (33.3%) men with hCG negative tumors before orchiectomy. Before surgery, 10 men without detectable gonadotropin levels showed complete suppression of the LH and FSH responses to LH-RH and 10 men with detectable gonadotropin levels showed significant increases in the LH and FSH responses (p < 0.01) at 30 minutes. After surgery, the Gn-RH test was performed in 9 men without detectable gonadotropin levels prior to surgery. Seven of these 9 men exhibited significant increases in the LH and FSH responses (p < 0.01) at 30 minutes while no response to LH-RH before or after surgery was seen in 2 men with detectable serum hCG-beta. We observed a significantly lower sperm density (median 7.5 x 10(6)/ml, range 0.4 to 17.8) in men with hCG positive tumors than in men with hCG negative tumors (median 33 x 10(6)/ml, range 0 to 103) (p < 0.002). Although testosterone levels did not differ significantly in men with hCG positive tumors and men with hCG negative tumors, free testosterone levels were significantly higher in men with hCG positive tumors (median 28.4 ng/ml, range 8.5 to 39.8) compared with men with hCG negative tumors (median 18.7 ng/ml, range 4.9 to 24.1) (p < 0.002). Estradiol levels were significantly increased in men with hCG positive tumors (median 44 pg/ml, range 26 to 110) compared with men with hCG negative tumors (median 33.5 pg/ml, range 10 to 87) (p = 0.002). CONCLUSION: The present findings indicate that serum hCG producing testicular cancers are associated with a complete suppression of the gonadotropin response to Gn-RH at the pituitary level, resulting in an inhibition of LH and FSH secretion, and also that serum hCG secreted by testicular cancers may suppresses spermatogenesis and may stimulate androgen and estradiol production by the testes. Since suppressed serum gonadotoropin levels are found in men with hCG non-producing testicular cancers, other factors derived from the tumor may cause downregulation of the gonadotropin response to Gn-RH.     

Heparin-coated cardiopulmonary bypass circuits reduce circulating complement factors and interleukin-6 in paediatric heart surgery

Children are sensitive to the inflammatory side effects of cardiopulmonary bypass (CPB). Our intention was to investigate if the biocompatibility benefits of heparin-coated CPB circuits apply to children. In 20 operations, 19 children were randomized to heparin-coated (group HC, n = 10) or standard (group C, n = 10) bypass circuits. Plasma levels of acute phase reactants, interleukins, granulocytic proteins and complement factors were measured. All were significantly elevated after CPB. Levels of complement factor C3a (851 (791-959)ng/ml [median with quartiles] in group C, 497 (476-573)ng/ml in group HC, p < 0.001), Terminal Complement Complex (114 (71-130) AU/ml in group C, 35.5 (28.9-51.4) AU/ml in group HC, p < 0.001), and interleukin-6 (570 (203-743) pg/ml in group C, 168 (111-206)pg/ml in group HC, p = 0.005), were significantly reduced in group HC. Heparin-coated CPB circuits improve the biocompatibility of CPB during heart surgery in the paediatric patient population, as reflected by significantly reduced levels of circulating complement factors and interleukin-6.     

Pump-induced platelet aggregation in albumin-coated extracorporeal systems.

OBJECTIVE: Coating of extracorporeal systems with heparin does not prevent platelet activation and subsequent bleeding disorders. We investigated whether this could be due to elevated shear stress caused by a roller pump. METHODS: Human or rat blood was made to flow through an uncoated or an albumin-coated medical polyvinyl chloride tube with or without a roller pump. Aggregation of platelets in the tubing was recorded continuously with a photometric device. RESULTS: Although in vitro gravitational flow in uncoated tubes caused immediate platelet aggregation and platelet loss, this remained absent in coated tubes. When the pump was started in experiments with a coated tube strong platelet aggregation was observed and platelet count fell within 5 minutes to 78% +/- 2% and 71% +/- 3% of control values in human and rat blood, respectively. In vivo, no aggregation was observed during spontaneous flow in rats with an albumin-coated tube running from the carotid artery to the femoral artery, but aggregation started as soon as the blood was pumped. Pump-induced platelet aggregation, both in vitro and in vivo, could be prevented with aurintricarboxylic acid, which specifically inhibits shear-induced platelet aggregation as has recently been shown. Pump perfusion of blood in an uncoated tube did not elicit platelet aggregation. CONCLUSIONS: Pump perfusion of blood in coated systems elicits shear-induced platelet aggregation, which may be prevented by administration of substances that block the binding of von Willebrand factor to glycoprotein Ib receptors on the platelets. The effects of pumping on platelets are masked in uncoated circuits because of the dominant influence of blood-material contact.     

Influence of Two Blood Conservation Techniques (Cardiotomy Reservoir Versus Cell-Saver) on Biocompatibility of the Heparin Coated Cardiopulmonary Bypass Circuit During Coronary Revascularization Surgery

A bstract Blood conservation during cardiac surgery is critically important because of the inherent risks in homologous blood transfusions. Two techniques for the intraoperative conservation of blood—retransfusion of the red cells using a cell-saver (CS), or retransfusion of the blood using a cardiotomy suction (CTR) system—were compared using biocompatibility markers, granulocyte activation, and production of oxygen-free radicals (OFR). In the CTR group, heparin coated circuits with an uncoated cardiotomy reservoir were used. For the CS group, identical heparin coated cardiopulmonary bypass (CPB) sets, without a cardiotomy reservoir but with a CS, were used. In each group, eight patients had coronary artery bypass grafting performed. The capacity of the whole blood and the granulocytes to produce OFR was estimated by a chemiluminescence, and granulocyte activation was measured as release of the granulocyte granule proteins myeloperoxidase (MPO) and lactoferrin. A significantly reduced capacity to produce OFR by the whole blood was noted at 45 minutes of CPB in the CTR group (68%± 17% vs 94%± 16% in the CS group). MPO release was higher after 3 hours (p = 0.05) and 20 hours (p < 0.05), postoperatively, in the CTR group (417 ± 77 μg/L and 257 ± 31 μg/L vs 246 ± 25 μg/L and 164 ± 12 ng/L, respectively, in the CS group). We conclude that the heparin coated CPB circuit with the uncoated cardiotomy reservoir may be less biocompatible than the identical CPB set used together with the CS.     

Antihemostatic and antithrombotic effects of monoclonal antibodies against von Willebrand factor in nonhuman primates.

BACKGROUND. Because the adhesive glycoprotein von Willebrand Factor (vWF) mediates initial platelet attachment at sites of vascular injury and may also contribute to shear-dependent platelet thrombus formation, we have determined in vivo the relative antithrombotic efficacy and hemostatic safety of infusing murine monoclonal antibodies against vWF. METHODS. In baboons with chronic arteriovenous shunts, thrombus formation was initiated by interposition of thrombogenic Dacron vascular grafts (VG) and endarterectomized baboon aortic segments (EAS). Thrombus formation on VG and EAS was assessed by use of real-time scintillation camera imaging of indium 111-labeled platelet deposition. In control and treated animals (anti-vWF antibody) platelet hemostatic competence was evaluated by means of serial measurements of platelet count, bleeding time, and ex vivo platelet aggregation in response to adenosine diphosphate and ristocetin. RESULTS. Although bolus antibody infusions did not affect circulating platelet counts, bleeding times were immediately prolonged to 28 +/- 4 minutes (vs 4.7 +/- 0.4 minutes before treatment, p = 0.01). Bleeding times normalized within 24 hours after antibody administration. Platelet aggregation in response to adenosine diphosphate was unchanged by antibody therapy, whereas ristocetin-induced platelet aggregation was abolished acutely and remained impaired for 24 hours. Platelet deposition on VG after 60 minutes of exposure to flowing blood was 2.95 +/- 0.74 x 10(9) platelets/cm in six control animals as compared to 1.86 +/- 0.16 x 10(9) platelets/cm in five treated animals (p = 0.04). Similarly, platelet deposition on EAS averaged 4.40 +/- 0.89 x 10(9) platelets/cm in control studies and was reduced significantly by antibody therapy (1.52 +/- 0.50 x 10(9) platelets/cm, p = 0.02). CONCLUSIONS. Despite profound interruption of platelet hemostatic functions, therapeutic targeting of vWF modestly inhibits platelet-dependent thrombosis.