Is it possible to predict outcome in pulmonary ECMO? Analysis of pre-operative risk factors.

Serious pulmonary failure may be treated with extracorporeal membrane oxygenation (ECMO) when other treatment has failed. The aim of this study was to analyze pre-operative risk factors of early mortality in patients who underwent either veno-arterial (VA) ECMO or veno-venous (VV) ECMO for pulmonary failure. We studied a total of 26 risk factors in 72 patients with severe pulmonary insufficiency treated with ECMO. All consecutive cases treated at our institution between Sept 1990 and Aug 2007 were included. Univariate analysis and multiple logistic regression analysis were performed on 26 risk factors. The end point was early mortality (any death within 30 days of ECMO treatment). Thirty-six (50%) of the patients died within 30 days of treatment. Age, gender, body mass index(BMI)(adults), cause of pulmonary failure, pre-ECMO treatment with nitric oxide(NO), intra-aortic balloon pump(IABP), and type of ventilation did not significantly influence early mortality. Neither pre-operative blood gas results, oxygenation index or pre-operative PaO(2)/FiO(2) ratio, nor mean ventilator days prior to ECMO gave any indications on early mortality. Liver function did not predict early mortality, but pre-ECMO serum creatinine levels were significantly lower in patients who survived. Treatment with ECMO in patients with severe pulmonary failure may save lives. It is, however, difficult to predict outcome when initiating ECMO. In this analysis, only pre-operative serum creatinine levels correlated with survival. None of the other parameters, including those which were used to select patients for ECMO treatment, could significantly predict the outcome.

Transportation of critically ill patients on extracorporeal membrane oxygenation.

Serious pulmonary and cardiac failure may be treated with extracorporeal membrane oxygenation (ECMO) when conventional treatment fails. In some severely ill patients, it may be necessary to initiate ECMO at the local hospital and, thereafter, transport the patient back to the ECMO center. The aim of this study was to evaluate our experiences with transportation of patients on ECMO. From Oct 1992 to Jan 2008 23, patients were transported on ECMO from local hospitals to Rikshospitalet. The study included seventeen patients with pulmonary failure and four patients with cardiac failure. All age groups were represented. Aircraft were used in 17 cases, ground vehicles in six. The times from decision until ECMO was established, the time from ECMO to departure from the local hospital and the transportation time were registered. All transportations were uneventful. After 10.3 +/-6.7 days, six patients died on ECMO and another patient died within 30 days. Mean ECMO time for those who died was 13.3 +/- 9.6 vs. 8.5 +/- 4.7 days for survivors, p=0.34. Seventeen patients were able to be successfully weaned from ECMO. Thirty day survival was 67%. The mean age for survivors was 15.3+/-18.3 (range 0-54.6) vs. 23.6 +/- 20.3 years (range 0-55.9) in fatal cases, p=0.41. The time from referral to initiating ECMO was a mean of 7.32 +/- 2.3 (3.0-12.0) hours for survivors vs. 7.88 +/- 3.0 (3.50-13.40) hours for non- survivors, p=0.76. The time from initiating ECMO to departure was 5.1 +/- 6.5 (0.58-23.75) hours in survivors vs. 9.1 +/- 6.8 (0.55-18.45) hours in non-survivors, p=0.18. Time from departure to arrival at Rikshospitalet was a mean of 3.2 (0.50-5.10) hours for survivors versus 2.5 (0.5-4.40) for non-survivors, p=0.41. This study shows that ECMO can be successfully established at local hospitals, using an experienced team, and that transportation of patients on ECMO can be performed safely and without technical difficulties. Survival for this group of patients did not differ from patients treated at the ECMO center.

Evaluation of oxygenators and centrifugal pumps for long-term pediatric extracorporeal membrane oxygenation.

OBJECTIVE: Two extracorporeal membrane oxygenation (ECMO) circuits for children under 10 kg were evaluated and compared for plasma leakage, hemolysis, blood transfusions, and durability. METHODS: Group A (n=20) was supported by ECMO circuits with the Minimax oxygenator and the Biomedicus centrifugal pump. Group B (n=10) was supported by ECMO circuits with the Lilliput 2 ECMO oxygenator and the Rotaflow centrifugal pump. RESULTS: ECMO circuit durability, as measured by oxygenator lifespan, was significantly better in Group B than in Group A (p = 0.04). There was significantly lower hemolysis, measured by plasma free hemoglobin, in Group B (p = 0.019), and patients in Group B had significantly less need for antithrombin III transfusion (p = 0.004). No plasma leakage was observed in Group B oxygenators, but plasma leakage was observed in all Group A oxygenators. CONCLUSION: The combination of a Rotaflow centrifugal pump and Lilliput 2 ECMO oxygenator in pediatric ECMO circuits improved durability and reduced circuit-induced hemolysis. This improvement may be due to the low priming volume, the oxygenator's plasma leakage resistance, the suspended rotor of the centrifugal pump, or a combination of these factors.

Sternal wound infections in patients undergoing open heart surgery: randomized study comparing intracutaneous and transcutaneous suture techniques.

BACKGROUND: Intracutaneous suture technique has been our standard method for closing sternal wounds in cardiac surgery, mainly for cosmetic reasons. However, an increased rate of postoperative infections has been reported in cosmetic surgery with this method compared with the percutanous or transcutaneous closure technique. A comparison of these two techniques in cardiac surgery is presented. METHODS: In a randomized study, 300 patients were selected to intracutaneous suture (n = 150) or percutanous suture (n = 150). The endpoints were superficial and deep sternal wound infections within 6 weeks postoperatively. RESULTS: The total infection rate was lower in the percutanous group compared with the intracutaneous group (3% versus 8%) (p = 0.007). The superficial infection rate was lower in the percutaneous group (2.3% versus 6.7%) (p = 0.01), whereas there was no statistically significant difference in the deep infection rate between the groups. CONCLUSIONS: The percutaneous suture technique reduces the incidence of superficial wound infections, but not the deep infection rate in open heart surgery. There was no difference in the cosmetic results on a visual scale, assessed by the patients.

Graft control by transit time flow measurement and intraoperative angiography in coronary artery bypass surgery.

BACKGROUND: The aim of this study was to compare the relationship between intraoperative transit time flow measurements and angiographic findings with long-term graft patency in 72 patients who underwent coronary artery bypass surgery. METHODS: Transit time flow measurements with recording of mean flow and pulsatility indexes were performed after completion of the anastomoses. Coronary angiography was performed on-table while the patients were still in general anesthesia, and then at follow-up three months and 12 months after surgery. Based on angiography, the grafts were graded as type A (fully patent), type B (having more than 50% diameter reduction), or type O (occluded). RESULTS: Of the 67 left internal mammary artery (LIMA) grafts, 51 (76%) were type A on-table, 14 (21%) were type B, and two (3%) were type O. Of the 57 saphenous vein grafts, 49 (86%) were type A, 7 (12%) were type B, and one (2%) was type O. For both LIMA and vein grafts, there were no differences in flow (p = 0.69 and 0.47, respectively) or pulsatility index (p = 0.79 and 0.83) between type A and B. There were also no differences in flow (p = 0.37 and 0.7) or pulsatility index (p = 0.37 and 0.24) between type B on-table that either normalized or persisted occluded at the follow-up. Transit time flow measurement failed to detect an occluded LIMA graft as shown by intraoperative angiography. CONCLUSIONS: Blood flow measurements performed intraoperatively could not identify significant lesions in arterial or vein grafts, and could not predict graft patency. We have become cautious in interpreting flow measurements alone and combine blood flow recordings with intraoperative angiography in the assessment of graft quality.

Transthoracic intra-aortic balloon pump in open heart operations: techniques and outcome.

OBJECTIVE: During open heart surgery, direct transthoracic insertion of the intra-aortic balloon pump (IABP) is an alternative to the routine transfemoral insertion especially in the presence of severe peripheral vascular disease. METHODS: Over 19 years (1980-1998), 646 patients were treated with IABP. In 24 of them, the balloon was inserted transthoracic (TIABP) due to failure of transfemoral insertion in 13 or extensive occlusive aorto-iliac disease in 11 cases. RESULTS: Early mortality was 58.3% in patients having TIABP compared to 46.1% in patients with transfemoral IABP insertion (p > 0.2). Of the 24 patients receiving IABP transthoracic, none suffered vascular injury (i.e. perforation or dissection). Complications which could be related to TIABP occurred in 10 patients: 3 balloon ruptures, 1 mediastinal haemorrhage, 3 cerebrovascular accidents, 1 post-operative mediastinitis, and 2 late graft infections. CONCLUSIONS: TIABP is a useful alternative when transfemoral insertion of IABP is not feasible or hazardous because of occluded or severely diseased ilio-femoral arteries. Being a second choice and a more invasive treatment, transthoracic IABP is associated with increased mortality.

Intraaortic balloon pumping for predominantly right ventricular failure after heart transplantation.

BACKGROUND: Right ventricular failure from elevated pulmonary vascular resistance in the recipient is a main cause of early mortality after heart transplantation. When pharmacologic treatment is insufficient, mechanical circulatory assistance has been used to support the failing right ventricle. Considering right and left ventricular interdependence, we investigated whether intraaortic balloon counterpulsation (IABP) might also alleviate predominantly right ventricular dysfunction after heart transplantation. METHODS: Among 278 cardiac recipients, 12 adult patients underwent mechanical circulatory support for cardiac allograft dysfunction. Five patients were treated with percutaneous IABP for early postoperative low cardiac output syndrome characterized by predominantly right ventricular failure. Clinical data and hemodynamic variables were recorded before and during IABP treatment. RESULTS: Cardiac index (CI) and mean arterial pressure (MAP) increased (CI 1.7 +/- 0.1 to 2.5 +/- 0.2, MAP 53 +/- 12 to 71 +/- 7, p < 0.05) within 1 hour after IABP, whereas central venous pressure (CVP) and pulmonary artery wedge pressure (PAWP) decreased (CVP 21.6 +/- 1.7 to 13.8 +/- 3.1, p < .05; PAWP 14.8 +/- 4.9 to 12.4 +/- 3.7, nonsignificant). Within the next 12 hours, CI and mixed venous oxygen saturation increased (p < 0.05) and pulmonary artery pressure decreased (p < 0.05). All 5 patients were weaned successfully and 4 are long-term survivors with adequate cardiac performance at 1 year follow-up. CONCLUSIONS: Intraaortic balloon pumping is a minimally invasive circulatory assist device with proved efficiency in low cardiac output syndromes. This report shows that low output syndrome caused by predominantly right ventricular allograft failure may be an additional indication for IABP.

Plasma endotoxin concentrations during cardiac surgery may be related to atherosclerosis.

Systemic endotoxemia develops during cardiopulmonary bypass, probably due to intestinal ischaemia. Differences in endotoxaemia among various cardiac operations and the relationship between endotoxemia and postoperative complications were studied in high-risk patients. Blood samples were obtained at termination of bypass in 136 adults undergoing elective cardiac surgery. Postoperative complications were registered prospectively. Plasma endotoxin was quantified by a kinetic limulus amebocyte lysate assay. Mean endotoxin concentrations were significantly lower in patients undergoing isolated valve replacement (89 ng/l) than in patients undergoing coronary artery bypass grafting alone (234 ng/l), or combined with valve replacement (278 ng/l) or carotid artery surgery (321 ng/l) (p < 0.05). In multivariate linear regression, only the number of grafts (0, 1-3, 4-5) was significantly correlated to endotoxin concentrations (p < 0.0005). Endotoxin concentrations were related to development of gastrointestinal dysfunction (p = 0.03), but not to mortality (p = 0.24) or other complications (p = 0.62).

Duration of preoperative electrocardiographic QRS complex and the incidence of heart arrest after aorto coronary bypass surgery.

Sudden heart arrest (HA) in the early phase after aorto coronary bypass surgery represents a serious event necessitating resuscitation, and for those who survive usually also an extra stay in the coronary care unit. Since such episodes of heart standstill may be related to conduction defects, a study was conducted to determine whether the duration of the QRS complex on the preoperative ECG is a marker for this morbid event. A cohort of 1011 consecutive patients operated on between 1982 and 1986 and followed to January 1st, 1993 were included in the study. Incidence of lethal or non-lethal HA during the first 4 weeks after surgery was considered as the primary endpoint and total mortality as the secondary endpoint. The incidence of HA was 40/1011 = 4%, with the majority of events (60%) being lethal. Independent risk factors of HA using the multivariate logistic model were previous coronary artery bypass surgery, presence of mitral regurgitation, left ventricular ejection fraction and the intraoperative cross-clamp time of aorta. Adjusting for the effect of confounder variables showed that the gradient effect of QRS complex duration on the endpoint HA was still present (p = 0.012). The duration of the QRS complex taken from the preoperative ECG had a gradient effect on the incidence of HA. With a baseline level of QRS <70 ms, the following odds ratios (OR) for HA were found: OR = 1.38 (95% CI 0.60-3.31) for QRS 70-80 ms; OR = 2.27 (95% CI 0.87-5.90) for QRS >90-120 ms; and OR = 3.38 (95% CI 1.06-11.50) for QRS > 120 ms, when adjusting for the risk factors. Cumulative survival at 5 years after surgery was 28+/-7.1% for patients experiencing HA versus 87+/-1.2% for patients free from this event. Our results underline the importance of the QRS complex duration as a preoperative marker for HA after aorta coronary bypass surgery, when adjusting for other risk factors. Although the one-year survival is poor for patients experiencing HA, there is no increase in mortality during the late follow-up.

Viral safety of solvent/detergent-treated plasma.

BACKGROUND: Pooling of plasma donations increases the risk for blood-borne infections. In solvent/detergent (SD)-treated plasma, lipid-enveloped viruses are efficiently inactivated. This method, however, does not affect non-lipid-enveloped viruses. The current study investigated the viral safety of SD-treated plasma (Octaplas) and paid particular attention to the transmission of non-lipid-enveloped viruses. STUDY DESIGN AND METHODS: The study comprised 343 adults undergoing cardiac surgery. Follow-up was performed 6 to 12 months and 2 years after operation. The sera were tested for hepatitis B surface antigen and specific antibodies against hepatitis A, B, and C; cyto-megalovirus; HIV, human T-lymphotropic virus types I and II; and human parvovirus B19 (B19). A total of 25 batches of SD-treated plasma prepared from Norwegian plasma were used. All batches were tested for hepatitis A virus and B19 by nucleic acid amplification testing and investigated for neutralizing antibodies directed against these viruses. RESULTS: In patients who received SD-treated plasma, B19 seroconversion occurred at a rate similar to that in nontransfused patients. No other seroconversions could be ascribed to the transfusion of SD-treated plasma. All 25 SD-treated plasma batches contained neutralizing antibodies against hepatitis A virus and B19. In nucleic amplification testing, all SD-treated plasma batches tested positive for B19, while five demonstrated borderline reactions for hepatitis A virus. CONCLUSION: Transfusion of SD-treated plasma was found to be safe with regard to lipid-enveloped viruses. Immune antibodies neutralize viral particles in plasma and are of importance in avoiding clinical disease with the non-lipid-enveloped hepatitis A virus and B19.

[Cardiac tumors]. / Svulster i hjertet.

BACKGROUND: Tumours of the heart are rare, but of great clinical interest as the majority are benign and amenable to radical excision. MATERIAL AND METHODS: We report on 30 patients with cardiac tumours resected at the National Hospital, Oslo, Norway from 1990 to 1999. Data were obtained from patient files. RESULTS: 27 patients had benign tumours, 25 of which were myxomas predominantly located in the left atrium. One patient had a primary malignant tumour (rhabdomyosarcoma) and two had secondary malignant tumours (metastases from malignant tumours). All patients were alive at follow-up four to ten years after operation. INTERPRETATION: Patient with benign tumours are cured by surgery, whereas in malignant primary tumours the surgery will most often be palliative. Surgery for cardiac metastases may be indicated in selected symptomatic patients.

Leucocyte filtration during cardiopulmonary reperfusion in coronary artery bypass surgery.

Postoperative organ dysfunction after cardiac operations has been related to the damaging effects of cardiopulmonary bypass (CPB). These complications are considered to be mediated partly by complement activation and subsequent activation of leucocytes due to the contact between blood and the large nonendothelial surfaces in the bypass circuit. Removal of leucocytes by filtration during the reperfusion period may potentially reduce the postoperative morbidity after CPB. Forty patients undergoing elective, primary coronary artery bypass grafting were randomized to initial identical bypass circuits until the aortic crossclamp was released. Then, the ordinary arterial line filter was closed and either a leucocyte depletion filter (n = 20), or a control filter (n = 20) was incorporated in the circuits during the reperfusion period of CPB. Blood samples were drawn at fixed intervals and analysed for white blood cell and platelet counts, plasma concentration of myeloperoxidase, C3-complement activation products, the terminal complement complex, and interleukins (IL)-6 and -8. The numbers of circulating white blood cells in the leucocyte-depleted group decreased during the reperfusion period from 5.5 (4.8-6.8) to 5.3 (4.4-6.2) x 10(9)/l, and increased in the control group from 6.5 (5.1-8.0) to 7.4 (5.7-9.0) x 10(9)/l. Two hours postoperatively the total white blood cell count in the leucocyte-depleted group was 14.7 (12.1-17.2) x 10(9)/l, and in the control group 17.6 (14.5-20.7) x 10(9)/l. The differences between the groups were statistical significant (p = 0.05). There were no statistically significant differences between the groups with regard to other test parameters or clinical data. We conclude that the use of leucocyte filters during the reperfusion period in elective coronary artery bypass surgery significantly reduced the number of circulating leucocytes, whereas no effects were seen for granulocyte activation measured as myeloperoxidase release, platelet counts, complement activation, or IL-6 and -8 release. The clinical benefit of leucocyte filters in routine or high risk patients remains to be demonstrated and is suggested to be dependent on both the efficacy and the biocompatibility of the filters.

Comparison of three oxygenator-coated and one total-circuit-coated extracorporeal devices.

The present study was designed to compare the biocompatibility of three cardiopulmonary bypass setups with different surface coatings, and to determine if coating of the whole circuit with one of the coatings was more beneficial than coating of the oxygenator only. Extracorporeal devices entirely coated with synthetic polymers (Avecor, n = 6) were compared to oxygenators coated with synthetic polymers (Avecor, n = 6), end-point, covalently attached heparin (CBAS, n = 6) or absorbed heparin (Duraflo 2, n = 6) in an in vitro model of a heart lung machine. The circuits were primed with fresh human whole blood and Ringer's acetate and recirculated at 4 l/min at 30 degrees C for 2 h. Test samples were obtained at regular intervals and analysed for myeloperoxidase (MPO), platelet counts, beta-thromboglobulin, heparin, prothrombin fragment 1+2, plasmin anti-plasmin complexes, and complement activation products. The mean MPO concentrations increased in the Avecor-coated oxygenator group (AV) from 247 at the start to 671 microg/l at the termination of the experiments, in the Avecor-coated total circuit group (AV-T) from 116 to 288 microg/l, in the Duraflo 2 coated oxygenator group (DU) from 160 to 332 microg/l, and in the CBAS-coated oxygenator (CA) group from 172 to 311 microg/l. The MPO concentrations increased significantly in all groups (p < 0.03). The increase in group A was significantly higher than in the other three groups (p = 0.007). The mean platelet counts decreased in the Avecor-coated total circuit group from 117 at start to 99 x 10(9)/l at termination of the experiments, in the Avecor-coated oxygenator group from 119 to 103 x 10(9)/l, in the Duraflo 2 group from 96 to 86 x 10(9)/l, and in the CBAS group from 132 to 123 x 10(9)/l. The platelet counts decreased significantly in all groups (p < 0.01), but the intergroup differences were not significant (p = 0.15). The mean beta-thromboglobulin concentrations increased in the Avecor-coated total circuit group from 193 at the start to 754 ng/ml at the termination of the experiments, in the Avecor-coated oxygenator group from 474 to 1654 ng/l, in the Duraflo 2 group from 496 to 1280 ng/l, and in the CBAS group from 418 to 747 ng/l. The beta-thromboglobulin increase was significant in each group (p < 0.01), but not between the groups (p = 0.49). The mean heparin concentrations in the Duraflo 2 group increased from 2460 at the start to 2897 IU/l at termination of the experiments, in the CBAS group from 2468 to 2518 IU/l. In the Avecor-coated oxygenator group heparin concentrations decreased from 2010 to 1968 IU/l, and in the Avecor-coated total circuit group from 2002 to 1927 IU/l. The differences in heparin concentrations were significant between the Duraflo 2 group and the other groups (p < 0.05). The mean prothrombin fragment 1+2 concentrations increased in the CBAS group from 0.4 at the start to 2.1 nmol/l at the end of the experiments, in the Avecor-coated oxygenator group from 0.4 to 0.6 nmol/l, in the Avecor-coated total circuit group from 0.3 to 0.4 nmol/l, and in the Duraflo 2 group from 1.2 to 1.3 nmol/l. The prothrombin fragment 1+2 increase was significant in all groups (p < 0.05), but there were no significant intergroup differences (p = 0.54). There were no significant differences at the termination of the experiments among the four groups regarding complement activation as measured by C3 activation products and the terminal complement complex. In the present in vitro model of a heart-lung machine, none of the three specific setups with different coatings was superior with regard to all test parameters. The CBAS group generated the highest levels of prothrombin fragment 1+2 formation, but least complement activation. The increasing plasma heparin concentrations in the Duraflo 2 group indicated more unstable heparin bonding. The Avecor-coated total circuit group were superior to the Avecor-coated oxygenator group regarding plasma concentrations of MPO, but not compa

Vascular complications of the intraaortic balloon pump in patients undergoing open heart operations: 15-year experience.

BACKGROUND: The beneficial effects of the intraaortic balloon pump (IABP) in providing circulatory support must be weighed against its complications, particularly its vascular trauma. METHODS: Five hundred nine patients who underwent open heart operations at our institution and who were treated with the IABP from January 1980 through December 1994 were studied retrospectively to assess IABP-related vascular complications and their independent preoperative predictors and the implications of IABP-related vascular complications on the patients' mortality, morbidity (clinical sepsis and organ failure), and long-term survival. RESULTS: Early vascular complications occurred in 56 patients (11%) and major complications occurred in 41 patients (8%). The latter consisted of aortic perforation in 1 patient, aortoiliac dissection in 2 patients, and limb ischemia in 38 patients. Logistic regression analysis identified concomitant peripheral vascular disease (p<0.001), elevated preoperative end-diastolic pressure, small body surface area, and large catheter size (p<0.05) as independent risk factors for IABP-related major vascular complications in patients who survived the day of operation. Late IABP-related sequelae occurred in 10 patients, 9 of whom had had early vascular complications. The presence of vascular complications per se was not a significant independent factor among other risk factors for mortality, morbidity, or long-term survival. CONCLUSIONS: Careful clinical assessment of the aortofemoral vascular tree is a cornerstone of early diagnosis and early intervention and usually prevents limb loss. The significant decrease in major vascular complications that has occurred over the last 5 years can be explained by the increased use of catheters with smaller diameters. The timing of IABP insertion in relation to operation and the duration of IABP use were the only device-related risk factors identified for morbidity and survival.

In vitro evaluation of new surface coatings for extracorporeal circulation.

Cardiopulmonary bypass (CPB) exposes blood to large, foreign surfaces. This exposure may activate the cellular and humoral inflammatory systems, resulting in inflammatory reactions and organ dysfunction. Coating the inner surfaces of the bypass circuit may help alleviate these side-effects. The objective of this study was to determine the influence of two new surface treatments on blood cell and complement activation. Oxygenator and tubing sets coated with synthetic polymers (n = 7) or heparin (n = 7) were compared to uncoated sets (n = 7) in an in vitro model of CPB. The circuits were run at 4 l/min and recirculated for 120 min. The inflammatory response was assessed at regular intervals by platelet counts, and activation of complement, leucocytes and platelets. We found that the median platelet counts decreased from 127 to 122 x 10(9)/l (not significant, NS) in the synthetic polymer sets, from 96 to 88 x 10(9)/l (NS) in the heparin-coated sets, and from 93 to 54 x 10(9)/l (p < 0.01) in the uncoated sets after 2 h of recirculation. There were significant differences in platelet counts between the coated sets and the uncoated set at end of experiments (p < 0.05). Beta-thromboglobulin (BTG) concentrations increased in the synthetic polymer sets from 166 to 352 ng/ml (p < 0.01), in the heparin coated sets from 336 to 1168 ng/ml (p < 0.01), and in the uncoated sets from 301 to 3149 ng/ml (p < 0.01) after 2 h of recirculation. The differences in BTG at termination of the experiments were significant among all three sets (p < 0.05). Myeloperoxidase (MPO) concentrations in the synthetic polymer sets increased from 63 to 86 micrograms/l (p < 0.01), in the heparin-coated sets from 90 to 208 micrograms/l (p < 0.01), and in the uncoated sets from 122 to 513 micrograms/l (p < 0.01) after 2 h of recirculation. The differences in MPO at termination of the experiments were significant among all three groups (p < 0.01). There were no significant differences at termination of the experiments among the three sets regarding complement activation as measured by C3 activation products and the terminal complement complex. We conclude that in the current in vitro model of a CPB circuit, the synthetic polymer coating and the heparin coating caused significantly less platelet loss and granulocyte and platelet activation than the uncoated surface (p < 0.05). The synthetic polymer coating caused significantly less granulocyte and platelet activation than the heparin coating (p < 0.05). There was moderate complement activation within each group, but no significant differences among the three groups.

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