Let's understand nature better: de- and regeneration of autologous and artificial small caliber vascular grafts.
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Angioplasty, Balloon, Coronary↗
Biomedical subjects
L Eijsman
Publications and source records attributed to L Eijsman.
Cell-derived microparticles generated in patients during cardiopulmonary bypass are highly procoagulant.
BACKGROUND: Microparticles from platelets and other cells have been extensively studied and characterized in vitro. Although the level of platelet-derived microparticles is elevated in a variety of diseases, including cardiac surgery, virtually nothing is known about their functions in vivo. The aim of the present study was to investigate the procoagulant properties of microparticles generated in vivo. METHODS AND RESULTS: In 6 patients at the end of cardiopulmonary bypass, 14.8 x 10(9)/L (median; range, 9.7 to 27.4 x 10(9)/L) platelet-derived microparticles were present in pericardial blood, whereas blood obtained from the systemic circulation contained 1.6 x 10(9)/L (median; range, 0.4 to 8.9 x 10(9)/L) of such microparticles, as determined by flow cytometry. Microparticles stained positively for phosphatidylserine as determined with labeled annexin V. In contrast to systemic blood, pericardial blood contained not only microparticles of platelet origin but also microparticles that originated from erythrocytes, monocytes, or granulocytes, and other hitherto unknown cellular sources. Plasma prepared from pericardial blood and to a lesser extent plasma from systemic blood obtained at the same time, stimulated formation of thrombin in vitro. This activity of pericardial plasma was lost after removal of its microparticles by high-speed centrifugation, whereas the corresponding microparticle pellet was strongly procoagulant. The generation of thrombin in vitro involved a tissue factor/factor VII-dependent and factor XII-independent pathway. CONCLUSIONS: This study is the first to demonstrate that microparticles generated in vivo can stimulate coagulation.
Annexin A5↗
Activation of the complement system during and after cardiopulmonary bypass surgery: postsurgery activation involves C-reactive protein and is associated with postoperative arrhythmia.
BACKGROUND: Complement activation during cardiopulmonary bypass (CPB) surgery is considered to result from interaction of blood with the extracorporeal circuit. We investigated whether additional mechanisms may contribute to complement activation during and after CPB and, in particular, focused on a possible role of the acute-phase protein C-reactive protein (CRP). METHODS AND RESULTS: In 19 patients enrolled for myocardial revascularization, perioperative and postoperative levels of complement activation products, interleukin-6 (IL-6), CRP, and complement-CRP complexes, reflecting CRP-mediated complement activation in vivo, were measured and related to clinical symptoms. A biphasic activation of complement was observed. The ratio between the areas under the curve of perioperative and postoperative C3b/c and C4b/c were 3:2 and 1:46, respectively. IL-6 levels reached a maximum at 6 hours post-surgery. CRP levels peaked on the second postoperative day. Each complement-CRP complex had peak levels on the second or third postoperative day. By multivariate analysis, maximum levels of CRP on the second postoperative day were mainly explained by C4b/c levels after protamine administration, leukocyte count on the second postoperative day, and preoperative levels of CRP. Peak levels of C4b/c after protamine administration (P=.0073) and on the second postoperative day correlated with the occurrence of arrhythmia on the same day (P=.0065). CONCLUSIONS: Cardiac surgery with CPB causes a biphasic complement activation. The first phase occurs during CPB and results from the interaction of blood with the extracorporeal circuit. The second phase, which occurs during the first 5 days after surgery, involves CRP, is related to baseline CRP levels, and is associated with clinical symptoms such as arrhythmia.
Acute-Phase Reaction↗
Clinical evaluation of Duraflo II heparin treated extracorporeal circulation circuits (2nd version). The European Working Group on heparin coated extracorporeal circulation circuits.
OBJECTIVES: To evaluate whether the application of heparin treated circuits for elective coronary artery surgery improves postoperative recovery, a European multicenter randomised clinical trial was carried out. METHODS: In 11 European heart centers, 805 low-risk patients underwent cardiopulmonary bypass (CPB) with either an untreated circuit (n = 407) or an identical but heparin treated circuit (n = 398, Duraflo II). RESULTS: Significant differences were found among participating centers with respect to patient characteristics, blood handling procedures and postoperative care. The use of heparin treated circuits revealed no overall changes in blood loss, blood use, time on ventilator, occurrence of adverse events, morbidity, mortality, and intensive care stay. These results did not change after adjustment for centers and (other) prognostic factors as analysed with logistic regression. In both groups no clinical or technical (patient or device related) side effects were reported. Because female gender and aortic cross clamp time appeared as prognostic factors in the logistic regression analysis, a subgroup analysis with these variables was performed. In a subpopulation of females (n = 99), those receiving heparin treated circuits needed less blood products, had a lower incidence of rhythm disturbances and were extubated earlier than controls. In another subgroup of patients with aortic cross clamp time exceeding 60 min (n = 197), the amount of patients requiring prolonged intensive care treatment (> 24 h) was significantly lower when they received heparin treated circuits versus controls. CONCLUSION: These findings suggest that improved recovery can be expected with heparin treated circuits in specific higher risk patient populations (e.g. females) and when prolonged aortic cross clamp time is anticipated. Further investigations are recommended to analyses the clinical benefit of heparin treated circuits in studies with patients in different well defined risk categories and under better standardised circumstances.
Adult↗
Comparative vasoconstrictor effects of angiotensin II, III, and IV in human isolated saphenous vein.
Elevated levels of angiotensin (Ang II) and its degradation products angiotensin III (Ang III) and angiotensin IV (Ang IV) may contribute to the regulation of vascular tone under various clinical circumstances. We investigated the contractile effects of Ang III and Ang IV in endothelium-denuded human saphenous vein (SV) preparations and compared them with those of Ang II. The veins were suspended in organ chambers, and changes in isometric force were recorded. Ang II (0.1-100 nM), Ang III (1 nM-3 microM), and Ang IV (0.3 microM-0.1 mM) caused concentration-dependent contractions with comparable maximal responses (Emax). Ang III was 16 times less active than Ang II, whereas Ang IV was approximately 2,700-fold less potent than Ang II. In the presence of the aminopeptidase-A and -M inhibitor amastatin (10 microM), the potencies of Ang III and Ang IV were increased by approximately 16 and 12 times, respectively, although no changes of Ang II potency were observed. The AT1-selective Ang II receptor antagonist losartan (10 and 100 nM) but not the AT2-selective antagonist PD123177 (1 microM), shifted the concentration-response curves (CRC) for the angiotensin peptides to the right in a parallel manner. Preincubation with indomethacin (10 microM), a cyclooxygenase inhibitor, did not influence the CRCs for any of the angiotensin peptides studied. Tachyphylaxis was investigated by constructing a second series of CRCs for the angiotensin peptides after an interval of 60 min. Ang II showed strong tachyphylaxis (the Emax value of the second Ang II CRC was approximately 50% of the first), whereas Ang III and Ang IV did not. Our results indicate that in endothelium-denuded human SV, both Ang III and Ang IV are less potent but similarly efficacious vasoconstrictor agents compared with Ang II. Endogenous aminopeptidase activity may counteract the effects of the angiotensin peptides. The contractile responses to all three peptides are mediated via AT1-receptors but not AT2-receptors.
Aged↗
Biocompatibility of three different membrane oxygenators: effects on complement, neutrophil and monocyte activation.
The inflammatory reaction of extracorporeal circuits can be assessed by measuring complement activation and the release of activation markers of leucocytes. The purpose of this study was to compare three commercially available membrane oxygenators with respect to complement (C3a), granulocyte (lactoferrin) and monocyte (interleukin-6, IL-6) activation. Thirty patients undergoing cardiac surgery were randomly assigned to undergo cardiopulmonary bypass (CPB) with one of the following oxygenators: a polypropylene hollow-fibre membrane (group 1; 2.2 m2), a polypropylene flat-sheet membrane (group 2; 3.1 m2) or a silicone envelope membrane (group 3, 3.5 m2). In all patients, a significant increase in C3a in plasma occurred during CPB with peak levels after the administration of protamine sulphate. In blood samples taken before aortic crossclamp release, at the end of CPB, and 20 min after protamine administration C3a was significantly lower in group 1 than in the other two groups. Lactoferrin increased significantly during CPB in all patients without a significant difference between the groups. IL-6 did not increase during CPB, but raised significantly after 4 h in the intensive care unit in all groups. Moreover, IL-6 was significant lower in group 1 than group 3. The data suggest that the polypropylene hollow-fibre membrane oxygenator, i.e. the oxygenator with the smallest surface area, is more biocompatible than the other types, probably because of a smaller contact surface area.
Biocompatible Materials↗
Circulating endothelin in cardiac operations: influence of blood pressure and endotoxin.
BACKGROUND: Endothelin is involved in the control of cardiovascular and renal functions and acts as a neuromodulator. METHODS: In a prospective study among 15 male patients who underwent coronary artery bypass grafting, we investigated the release pattern and possible stimuli of circulating endothelin. RESULTS: We detected a steep increase in endothelin concentrations after the onset of cardiopulmonary bypass (CPB), and a second minor increase during CPB. The steep increase in endothelin concentrations correlated with the change in arterial pressures at the onset of CPB (r = -0.57; p < 0.03). The slow increase in endothelin concentrations during CPB, however, correlated with mean endotoxin levels during and after CPB (r = 0.60; p < 0.02). CONCLUSIONS: The change in arterial pressure at the onset of CPB seems to induce a steep and fast increase in circulating endothelin level, which is probably mediated through the baroreceptors. The slow increase in endothelin level during CPB is associated with increased circulating endotoxin concentration. It may be that either endothelin-mediated vasoconstriction induces endotoxin transmigration from the intestine or endotoxin stimulates secretion from endothelial cells.
Aged↗
Specific complement inhibition with heparin-coated extracorporeal circuits.
BACKGROUND: Although it is well established that heparin-coated extracorporeal circuits reduce complement activation during cardiac operations, little in vivo information is available on the reduction in alternative and classic pathway activation. METHODS: In a prospective, randomized study involving patients undergoing coronary artery bypass grafting with standard full heparinization, we compared heparin-coated circuits (Duraflo II) (10 patients) with uncoated circuits (10 patients) and assessed the extent of initiation of complement activation by detecting iC3 (C3b-like C3) concentrations, classic pathway activation by C4b/c (C4b, iC4b, C4c) concentrations, terminal pathway activation by soluble C5b-9 concentrations, and C3 activation by C3a (C3a desArg) and C3b/c (C3b, iC3b, C3c) concentrations. RESULTS: Heparin-coated extracorporeal circuits significantly reduced circulating complement activation product C3b/c and soluble C5b-9 concentrations at the end of cardiopulmonary bypass and after protamine sulfate administration compared with the uncoated circuits, but not iC3, C4b/c, or C3a concentrations. CONCLUSIONS: Heparin-coated extracorporeal circuits reduce complement activation through the alternative complement pathway, probably at the C3 convertase level, and, consequently, the terminal pathway. C3b/c seems to be a more sensitive marker than C3a to assess complement activation during cardiac operations.
Aged↗
The routine use of fresh frozen plasma in operations with cardiopulmonary bypass is not justified.
BACKGROUND: The negative influence of cardiopulmonary bypass on hemostasis has been documented. Although abnormalities in platelet function are reported as the major cause of postoperative blood loss related to this hemostasis defect, fresh frozen plasma is often used in operations with cardiopulmonary bypass because it is thought to contribute to the reduction of postoperative bleeding complications. This study was designed to evaluate the effect of the administration of fresh frozen plasma after cardiopulmonary bypass on blood loss, transfusion requirements, and a number of coagulation parameters. METHODS: In a prospective, randomized, double-blind clinical trial 50 patients (mean age 63 years; 35 men/15 women) undergoing elective operation with cardiopulmonary bypass were randomly assigned to one of two groups: group I (n = 24) received 3 units of fresh frozen plasma after operation and group II (n = 26) received an equal amount of Gelofusine plasma substitute. At seven points before, during, and after operation hemoglobin concentration, hematocrit level, thrombocyte count, and coagulation parameters were analyzed. Study endpoints were the volume of blood loss and the transfusion requirement. RESULTS: There were no significant differences between the two study groups in blood loss, transfusion requirement, coagulation parameters, or thrombocyte counts. CONCLUSION: The routine use of fresh frozen plasma in operations with cardiopulmonary bypass cannot be recommended.
Aged↗
Low-dose and high-dose aprotinin improve hemostasis in coronary operations.
Prophylactic aprotinin therapy has become a popular method to reduce bleeding associated with cardiac operations. Today essentially two dose regimens are used, a high-dose regimen with administration throughout the complete operative procedure and a low-dose regimen with administration only during bypass. In unblinded studies both regimens were found to be equally effective. This double-blind placebo-controlled study in 115 patients undergoing elective coronary artery bypass grafting was done to confirm these results without potential investigator bias. Intraoperative hemoglobin loss was significantly reduced (p < 0.01) by 42% in the high-dose group and by 17% in the low-dose group compared with loss in control subjects. Blood loss 6 hours after operation was 377 ml in the low-dose and 266 ml in the high-dose group compared with 630 ml in the placebo group (p < 0.05 and p < 0.001, respectively). The average number of transfusions with packed red blood cells was reduced 31% in the low-dose group and 45% in the high-dose group, but the reductions were not significant. In a subgroup of patients, markers for coagulation and fibrinolysis were studied to investigate whether a different extent of activation existed. Fibrinolysis as measured by D-dimer levels was completely inhibited by the high-dose regimen, but was only partly suppressed in the low-dose group as compared with findings in the placebo group. Thrombin generation during cardiopulmonary bypass as reflected by F1 + 2 levels was lower in patients treated with aprotinin, but the difference was not significant. Concentrations of thrombin inactivated by antithrombin III were not different between the groups. The observation that low-dose aprotinin significantly improved hemostasis but did not inhibit hyperfibrinolysis supports our previous finding that low-dose aprotinin mainly protects platelet adhesive function. The better result obtained with high-dose aprotinin may indicate the contribution of hyperfibrinolysis to bleeding after cardiopulmonary bypass. Because high-dose aprotinin is administered outside the period of full heparinization and might therefore increase the risk of thromboembolic complications, we propose a modification of the low-dose schedule to increase aprotinin levels sufficient for plasmin inhibition before release of the aortic crossclamp.
Antithrombin III↗
Effects of dobutamine and enoximone on transmitral and pulmonary venous flow characteristics in patients with left ventricular dysfunction after coronary artery bypass grafting.
OBJECTIVES: To assess the effects of dobutamine and enoximone on transmitral (TMF) and pulmonary venous flow (PVF) characteristics. DESIGN: Prospective and randomized. SETTING: A university hospital intensive care unit. PARTICIPANTS: Thirty patients with moderate left ventricular dysfunction after coronary artery bypass grafting (CABG). INTERVENTIONS: Patients received either dobutamine, 10 micrograms/kg/min, or enoximone, 20 micrograms/kg/min, for the treatment of a low cardiac index (CI) (< 2.2 L/min/m2). MEASUREMENTS AND MAIN RESULTS: Both drugs significantly (p < 0.05) increased CI from 1.91 +/- 0.17 (dobutamine) and 1.97 +/- 0.17 (enoximone) at baseline to 2.86 +/- 0.70 and 2.84 +/- 0.39 L/min/m2, respectively. Compared with the enoximone (enox)-treated group, the administration of dobutamine (dob) resulted in significantly (p < 0.05) greater increases in mean arterial pressure (dob: 18 +/- 9% v enox: -2 +/- 7%), heart rate (dob: 24 +/- 13% v enox: 3 +/- 5%) and pulmonary artery pressure (dob: 5 +/- 10% v enox: -4 +/- 9%). In contrast, the increase in stroke volume index was significantly less in the dobutamine-treated group (dob: 22 +/- 27% v enox: 41 +/- 21%). The TMF indices, peak E, and peak A wave increased significantly (p < 0.05) after both dobutamine (baseline: 37.3 +/- 6.7 and 41.1 +/- 9.3; max dose: 42.4 +/- 4.3 and 49.0 +/- 10.2 cm/s) and enoximone (baseline: 36.2 +/- 7.5 and 44.2 +/- 10.9; max dose: 40.5 +/- 5.0 and 49.4 +/- 12.1 cm/s) without significantly altering the E/A ratio. Only dobutamine significantly (p < 0.05) decreased isovolumic relaxation time from 109 +/- 24 to 94 +/- 21 ms. There was no significant change in isovolumic relaxation time between the dobutamine (-12% +/- 17%)- and the enoximone (-4% +/- 21%)- treated group. PVF recordings demonstrated a significant increase in time velocity integrals of the S wave with both dobutamine (12.2 +/- 3.1 v 13.7 +/- 3.2 cm) and enoximone (11.0 +/- 3.0 v 12.2 +/- 3.2 cm). No changes in the systolic fraction of the PVF were noted. CONCLUSIONS: There were no major differences in parameters reflecting diastolic function between the dobutamine- and the enoximone-treated groups.
Adult↗
Cardiopulmonary bypass with modified fluid gelatin and heparin-coated circuits.
We have assessed the efficacy of cardiopulmonary bypass (CPB) using normal colloid oncotic pressure (COP) in a randomized, controlled study of 20 patients undergoing elective coronary artery surgery using heparin-coated circuits. For CPB, we used either crystalloid priming 1650 ml (n = 10) or colloid priming 1650 ml (2.4% modified fluid gelatin, n = 10). While COP did not change during bypass in the colloid group, a decline was observed in the crystalloid group (P = 0.005). By the end of bypass, the decrease in COP compared with baseline (delta COP) was 8.5 (S.D. 1.1) mm Hg in the crystalloid group compared with 1.5 (2.1) mm Hg in the colloid group (P = 0.0001). delta COP correlated positively with fluid balance during bypass (r2 = 0.41, P = 0.002). Similar increments in complement factors C3b/c and C4b/c, tumour necrosis factor-alpha and neutrophil elastase, but not endotoxins, were found in both groups as indicators of a systemic inflammatory response. A clinical performance score composed of fluid balance, postoperative duration of intubation and the difference between rectal temperature and skin temperature was more favourable in patients treated with colloid priming (P = 0.03). Median postoperative hospital stay was 7 (range 5-16) days in the crystalloid group compared with 5 (4-8) days in the colloid group (P = 0.016). Regression analysis indicated that CPB time, fluid balance during operation and postoperative PO2/FlO2 ratio were independent factors that predicted postoperative hospital stay. From these preliminary results we conclude that in the absence of endotoxaemia, use of a normal COP during CPB with modified fluid gelatin in heparin-coated circuits resulted in an improved postoperative course an a reduction in hospital stay.
Aged↗
Endotoxaemia and postoperative hypermetabolism in coronary artery bypass surgery: the role of ketanserin.
In a randomized, double-blind clinical study in 29 patients undergoing elective coronary artery surgery, we assessed the role of ketanserin, an inhibitor of serotonin-induced vasoconstriction and weak alpha 1 sympathetic blocker, in reducing endotoxaemia and postoperative hypermetabolism. Male patients without major organ dysfunction were allocated randomly to receive either ketanserin or placebo. Hypermetabolism was defined as an increase in oxygen consumption in the early postoperative hours (delta Vo2). Circulating endotoxin (P = 0.04) and postoperative delta Vo2 (P = 0.03) were lower in the ketanserin patients. Endotoxaemia was associated also with low vascular filling. From these preliminary results we conclude that treatment with ketanserin during cardiac surgery may reduce but not abolish endotoxaemia and postoperative hypermetabolism.
Aged↗
Hemostatic efficacy of dipyridamole, tranexamic acid, and aprotinin in coronary bypass grafting.
Sixty patients (four groups of 15 patients) were entered in a randomized, controlled study to compare the efficacy of prophylactic treatment with dipyridamole, tranexamic acid, and aprotinin to reduce bleeding after elective coronary artery bypass grafting. Only patients with a preoperative platelet count of less than 246 x 10(9)/L were selected because a previous study showed that these individuals are at risk for increased postoperative bleeding. Compared to control subjects, postoperative blood loss 6 hours after operation was significantly reduced by tranexamic acid (674 +/- 411 versus 352 +/- 150 mL; p < 0.05) and by aprotinin (270 +/- 174 mL; p < 0.01). Dipyridamole did not reduce postoperative blood loss and was associated with complications in 3 patients. We conclude that hemostasis after cardiac operations can be improved with tranexamic acid and aprotinin. Dipyridamole appeared to be ineffective.
Aprotinin↗
Reduction in prime volume attenuates the hyperdynamic response after cardiopulmonary bypass.
BACKGROUND: A hyperdynamic response to cardiopulmonary bypass is characteristically observed in the post-operative course. To determine the effect of prime volume on the hemodynamic response, a database study was performed on patients who underwent elective coronary artery bypass grafting with an extracorporeal circuit with either a large prime volume (2,350-mL prime, n = 20) or a small prime volume (1,400-mL prime, n = 20). METHODS: Measurements were carried out at fixed time points before and after cardiopulmonary bypass (until 18 hours postoperatively) and include hematocrit, colloid oncotic pressure, fluid balance, and hemodynamic profile (mean of three measurements). RESULTS: The lower colloid oncotic pressure in the large prime group (16.2 +/- 0.6 mm Hg versus 19.1 +/- 1.1 mm Hg, p = 0.0002) was associated with a highly positive fluid balance (5.5 +/- 0.9 L versus 2.8 +/- 0.7 L, p = 0.0001). With the on-bypass hematocrit aimed at 22% to 23%, autologous blood was predonated by 16 patients in the small prime group but by none in the large prime group. Reinfusion of autologous blood resulted in a reduction in blood bank requirements (p = 0.03). Mean arterial pressure was 83 +/- 4 mm Hg for small prime versus 76 +/- 4 mm Hg for large prime (p = 0.01). Cardiac index was 2.9 +/- 0.2 L.min-1.m-2 for small prime versus 3.8 +/- 0.3 L.min-1.m-2 for large prime (p = 0.0001). Pulmonary vascular resistance index was 281 +/- 40 dyne.s.cm5.m-2 for small prime versus 188 +/- 22 dyne.s.cm5.m-2 for large prime (p = 0.0009). Oxygen delivery was 42 +/- 5 mL.min-1.m-2 for small prime versus 51 +/- 3 mL.min-1.m-2 for large prime (p = 0.004). Vasoactive medication was not different among groups. CONCLUSIONS: Reduction in prime volume attenuates the hyperdynamic response after cardiopulmonary bypass. Furthermore, an important reduction in blood bank products can be obtained with small prime volumes.
Aged↗
Myocardial performance in elderly patients after cardiopulmonary bypass is suppressed by tumor necrosis factor.
The aim of this study was to determine whether elderly patients (aged > or = 65 years, n = 20) in comparison with younger patients (aged < or = 55 years, n = 23) demonstrate a different biochemical and hemodynamic response to coronary artery bypass operations. In the elderly group, we calculated a smaller body surface area (p < 0.01) than that in the younger group, and more female patients were included in this group (p < 0.05). During cardiopulmonary bypass, the elderly had higher endotoxin plasma concentrations (p < 0.01) than the younger patients, and significantly more circulating tumor necrosis factor-alpha was found after operation (p < 0.04). In the intensive care unit, the elderly patients had a significantly higher pulmonary capillary wedge pressure (p < 0.001), a higher mean pulmonary artery pressure (p < 0.01), and a lower calculated left ventricular stroke work index (p < 0.05). Multivariate analysis for the postoperative outcome showed that the intergroup differences in tumor necrosis factor-alpha, mean pulmonary artery pressure, and pulmonary capillary wedge pressure could be explained mainly by the difference in age between the groups and that the calculated left ventricular stroke work index difference could be explained by the difference in circulating tumor necrosis factor-alpha levels. Thus in elderly patients higher circulating endotoxin and tumor necrosis factor-alpha concentrations were detected than in younger patients, which clinically resulted in a suppressed myocardial performance.
Age Factors↗
Hemostatic function of aspirin-treated platelets vulnerable to cardiopulmonary bypass. Altered shear-induced pathway.
The impaired hemostasis of aspirin-treated patients is an annoying problem during and after cardiopulmonary bypass. The hemostatic function of platelets comprises two mechanisms: the shear-induced and the cyclooxygenase pathways. Because the latter is inhibited in aspirin-treated patients, the hemostatic function depends mainly on the former pathway. To investigate the effect of cardiopulmonary bypass on the shear-induced pathway, a double-blind study of preoperative aspirin treatment (325 mg) and placebo was conducted in 40 patients undergoing coronary artery bypass grafting. Postoperative blood loss was higher in the aspirin-treated patients than in the placebo-treated patients (p < 0.05). The shear-induced hemostasis was monitored by the in vitro bleeding test (Thrombostat), which mimics bleeding through an injured arteriole. The shear-induced pathway of aspirin-treated platelets was not affected before cardiopulmonary bypass, but it was impaired more during the operation (p < 0.01) and remained worse afterward (p < 0.05), compared with that of placebo-treated platelets. The inhibitory effects of aspirin on thromboxane production and on collagen-induced platelet aggregation remained throughout the operation. In aspirin-treated platelets, the aggregation capacity induced by adenosine diphosphate was inhibited before the operation (p < 0.05) and showed substantial recovery during the operation (p < 0.05). These results suggest that the shear-induced pathway of aspirin-treated platelets is more vulnerable to cardiopulmonary bypass than the pathway in normal platelets and causes severe impairment of hemostasis afterward.
Adenosine Diphosphate↗
Reduced complement activation and improved postoperative performance after cardiopulmonary bypass with heparin-coated circuits.
A randomized controlled trial that involved 30 patients undergoing elective coronary artery bypass grafting was done to determine the effect of heparin-coated circuits and full heparinization on complement activation, neutrophil-mediated inflammatory response, and postoperative clinical recovery. Peak concentrations of terminal complement complex were 38% lower (p = 0.004) in 15 patients treated with heparin-coated circuits (median 775 micrograms/L, interquartile range 600 to 996) compared with those in 15 patients treated with uncoated circuits (median 1249 micrograms/L, interquartile range 988 to 1443). Although no significant intergroup differences in concentrations of polymorphonuclear neutrophil elastase were found, a positive correlation (rs = 0.74, p < 0.0007) was calculated between peak concentrations of terminal complement complex and polymorphonuclear neutrophil elastase. Differences in patient recovery were analyzed with use of a score composed of fluid balance, postoperative intubation time, and the difference between rectal temperature and skin temperature. The score was significantly lower in patients treated with heparin-coated circuits (p = 0.03), whereas its components showed no intergroup significance. We conclude that the use of heparin-coated circuits with full systemic heparinization results in improved biocompatibility, as assessed by complement activation, and leads to an improved postoperative recovery of the patient.
Body Temperature↗