Off-pump technique in coronary artery bypass grafting in elderly patients

Background: The use of cardiopulmonary bypass (CPB) during coronary artery bypass grafting (CABG) is associated with substantial morbidity and mortality, especially in the elderly. The purpose of this study was to evaluate the feasibility of beating heart coronary artery revascularization in patients aged at least 80 years. Methods: A retrospective chart review was carried out for 17 patients aged over 80 years who underwent isolated off‐pump CABG at the Tri‐Service General Hospital, Taiwan, during the period July 1999 to December 2000. The demographic characteristics, operative data, postoperative results and short‐term outcomes of patients were compared with those of 12 patients who underwent conventional CABG using CPB during the same time period. Results: The off‐pump group consisted of 13 men and four women with a mean age of 82.2 ± 0.9 years and an ejection fraction of 53.4 ± 4.1%. The on‐pump group consisted of eight men and four women with a mean age of 83.5 ± 0.5 and an ejection fraction of 42.0 ± 4.8%. The mean number of anastomoses performed per patient was 3.1 ± 0.3 in the off‐pump group and 3.0 ± 0.14 in the on‐pump group. There was no occurrence of stroke, myocardial infarction, re‐entry for bleeding or renal failure among patients in the off‐pump group. Intubation time (10.6 vs 48.4 h), intensive care unit stay (2.9 vs 4.2 days) and postoperative stay (12.7 vs 18.1 days) were significantly shorter in the off‐pump group than in the on‐pump group. No patient died in the off‐pump group, whereas one patient died in the on‐pump group. Conclusions: The results of this study suggest that the off‐pump technique is a safe and efficacious method for myocardial revascularization in elderly patients and that the short‐term outcome obtained with this technique are promising. Our data suggest that the off‐pump technique is preferable in these patients.     

Apolipoprotein E Levels in Pediatric Patients Undergoing Cardiopulmonary Bypass

Apolipoprotein E (apoE) may play a critical role in modulating the response to neurological injury after cardiopulmonary bypass (CPB) in children. Plasma samples were collected from 38 pediatric patients. Half of the patients received nonpulsatile flow and the other half underwent pulsatile flow during CPB. Plasma samples were collected at three time points: at baseline prior to incision (T1), 1 h after CPB (T2), and 24 h after CPB (T3). The study included 38 pediatric patients undergoing heart surgery (mean age 2.5 ± 2.1 years). Baseline apoE levels were low (<30 μg/mL) in 21 patients (55%). ApoE levels were significantly decreased at 1 h after CPB compared with baseline (22 ± 14 vs. 34 ± 18 μg/mL, P = 0.001). At 24 h after CPB, apoE levels were significantly increased compared with baseline (47 ± 25 vs. 34 ± 18 μg/mL, P = 0.002). Pulsatile mode was associated with lower apoE levels at 24 h after CPB compared with nonpulsatile mode (38 ± 14 vs. 57 ± 29 μg/mL, P = 0.018). ApoE levels correlated negatively with pump time (r = ?0.525, P = 0.021) and cross‐clamp time (r = ?0.464, P = 0.045) at 24 h following CPB for the nonpulsatile group but not for the pulsatile group. In this cohort of young children with congenital heart disease, baseline apoE levels were low in the majority of patients prior to surgery. ApoE levels decreased further at 1 h after CPB, and then significantly increased by 24 h. The mode of perfusion and the duration of pump time and clamp time influence the apoE levels after CPB. An improved understanding of these mechanisms may translate into the development of new techniques to improve the clinical outcomes after pediatric CPB.     

Centrifugal pump and roller pump in adult cardiac surgery: a meta-analysis of randomized controlled trials

Centrifugal pump (CP) and roller pump (RP) designs are the dominant main arterial pumps used in cardiopulmonary bypass (CPB). Trials reporting clinical outcome measures comparing CP and RP are controversial. Therefore, a meta‐analysis was undertaken to evaluate clinical variables from randomized controlled trials (RCTs). Keyword searches were performed on Medline (1966–2011), EmBase (1980–2011), and CINAHL (1981–2011) for studies comparing RP and CP as the main arterial pump in adult CPB. Pooled fixed‐effects estimates for dichotomous and continuous data were calculated as an odds ratio and weighted‐mean difference, respectively. The P value was utilized to assess statistical significance (P < 0.05) between CP and RP groups. Eighteen RCTs met inclusion criteria, which represented 1868 patients (CP = 961, RP = 907). The prevailing operation was isolated coronary artery bypass graft surgery (CP = 88%, RP = 87%). Fixed‐effects pooled estimates were performed for end‐of‐CPB (ECP) and postoperative day one (PDO) for platelet count (ECP: P = 0.51, PDO: P = 0.16), plasma free hemoglobin (ECP: P = 0.36, PDO: P = 0.24), white blood cell count (ECP: P = 0.21, PDO: P = 0.66), and hematocrit (ECP: P = 0.06, PDO: P = 0.51). No difference was demonstrated for postoperative blood loss (P = 0.65) or red blood cell transfusion (P = 0.71). Intensive care unit length of stay (P = 0.30), hospital length of stay (P = 0.33), and mortality (P = 0.91) were similar between the CP and RP groups. Neurologic outcomes were not amenable to pooled analysis; nevertheless, the results were inconclusive. There was no reported pump‐related malfunction or mishap. The meta‐analysis of RCTs comparing CP and RP in adult cardiac surgery suggests no significant difference for hematological variables, postoperative blood loss, transfusions, neurological outcomes, or mortality.     

Nitric oxide provides myocardial protection when added to the cardiopulmonary bypass circuit during cardiac surgery: Randomized trial

ObjectivesThe aim of this pilot study was to elucidate the effects of exogenous nitric oxide (NO) supply to the extracorporeal circulation circuit for cardioprotection against ischemia–reperfusion injury during coronary artery bypass grafting (CABG) with cardiopulmonary bypass (CPB).MethodsA total of 60 patients with coronary artery disease scheduled for CABG with CPB were enrolled in a prospective randomized study. Patients were allocated randomly to receive treatment according to standard or modified CPB protocol where 40-ppm NO was added to the CPB circuit during cardiac surgery. The primary endpoint was the measurement of cardiac troponin I (cTnI). The secondary end points consisted in the measurements of creatine kinase-muscle/brain fraction (CK-MB) and vasoactive inotropic score (VIS).ResultsNO delivered into the CPB circuit had a cardioprotective effect. The level of cTnI was significantly lower in NO-treated group compared with the control group 6 hours after surgery: 1.79 ± 0.39 ng/mL versus 2.41 ± 0.55 ng/mL, respectively (P = .001). The CK-MB value was significantly lower in NO-treated group compared with the control group 24 hours after surgery: 47.69 ± 8.08 U/L versus 62.25 ± 9.78 U/L, respectively (P = .001); and the VIS was significantly lower in the NO-treated group 6 hours after the intervention.ConclusionsNO supply to the CPB circuit during CABG exerted a cardioprotective effect and was associated with lower levels of VIS and cardiospecific blood markers cTnI and CK-MB.     

Inhaled iloprost to control pulmonary artery hypertension in patients undergoing mitral valve surgery: a prospective, randomized-controlled trial

Background: Pulmonary hypertension (PHT) is common in patients undergoing mitral valve surgery and is an independent risk factor for the development of acute right ventricular (RV) failure. Inhaled iloprost was shown to improve RV function and decrease RV afterload in patients with primary PHT. However, no randomized‐controlled trials on the intraoperative use of iloprost in cardiac surgical patients are available. We therefore compared the effects of inhaled iloprost vs. intravenous standard therapy in cardiac surgical patients with chronic PHT. Methods: Twenty patients with chronic PHT undergoing mitral valve repair were randomized to receive inhaled iloprost (25 μg) or intravenous nitroglycerine. Iloprost was administered during weaning from cardiopulmonary bypass (CPB). Systemic and pulmonary haemodynamics were assessed with pulmonary artery catheterization and transoesophageal echocardiography. Milrinone and/or inhaled nitric oxide were available as rescue medication in case of failure to wean from CPB. Results: Inhaled iloprost selectively decreased the pulmonary vascular resistance index after weaning from CPB (208 ± 108 vs. 422 ± 62 dyn·s/cm⁵/m², P<0.05), increased the RV‐ejection fraction (29 ± 3% vs. 22 ± 5%, P<0.05), improved the stroke volume index (27 ± 7 vs. 18 ± 6 ml/m², P<0.05) and reduced the transpulmonary gradient (10 ± 4 vs. 16 ± 3 mmHg, P<0.05). In all patients receiving inhaled iloprost, weaning from CPB was successful during the first attempt. In contrast, three patients in the control group required re‐institution of CPB and had to be weaned from CPB using rescue medication. Conclusions: In patients with pre‐existing PHT undergoing mitral valve surgery, inhaled iloprost is superior to intravenous nitrogylycerine by acting as a selective pulmonary vasodilator, reducing RV afterload and moderately improving RV‐pump performance.     

Comparative Effects of Pulsatile and Nonpulsatile Flow on Plasma Fibrinolytic Balance in Pediatric Patients Undergoing Cardiopulmonary Bypass

In the brain, the components of the fibrinolytic system, tissue plasminogen activator (tPA) and its endogenous inhibitor plasminogen activator inhibitor‐1 (PAI‐1), regulate various neurophysiological and pathological responses. Fibrinolytic balance depends on PAI‐1 and tPA concentrations. The objective of this study is to compare the effects of pulsatile and nonpulsatile perfusion on fibrinolytic balance in children undergoing pediatric cardiopulmonary bypass (CPB). Plasma PAI‐1 antigen and tPA antigen were measured in 40 children (n = 20 pulsatile and n = 20 nonpulsatile group). Plasma samples (1.5 mL) were collected (i) prior to incision, (ii) 1 h after CPB, and (iii) 24 h after CPB. PAI‐1 and tPA levels were measured at each time point. PAI‐1 and tPA levels were significantly increased at 1 h after CPB, followed by a decrease at 24 h. Nonpulsatile but not pulsatile CPB lowered PAI‐1 : tPA ratio significantly at 24 h (median PAI‐1 : tPA ratio 4.63 ± 0.83:1.98 ± 0.48, P = 0.03, for the nonpulsatile group and 4.50 ± 0.92:3.56 ± 1.28, P = 0.2, for the pulsatile group). These results suggest that pulsatile flow maintains endogenous fibrinolytic balance after pediatric cardiopulmonary bypass. Further studies are needed to define the clinical significance of these differences.     

Comparison Between D901 Lilliput 1 and Kids D100 Neonatal Oxygenators: Toward Bypass Circuit Miniaturization

Progress in biomaterial technology and improvements in surgical and perfusion strategy ameliorated morbidity and mortality in pediatric cardiac surgery. In this study, we describe our clinical experience comparing performance of two neonatal oxygenators. From January 2002 to March 2011, 159 infants with less than 5 kg body weight underwent heart surgery. Ninety‐four patients received a D901 Lilliput 1 oxygenator with standard bypass circuit (group A), while 65 received a D100 Kids with miniaturized bypass circuit (group B). Miniaturization consisted in shortened arterial, venous, cardioplegia, and pump‐master lines. Priming composition consisted in Ringer's acetate solution with addition of albumin and blood, with target hematocrit of 24% or greater. In group B cardiopulmonary bypass (CPB) was vacuum‐assisted and started with an empty venous line. Modified ultrafiltration and Cell‐Saver blood infusion was routinely applied in both groups. Average ± standard deviation (SD) age at repair was 37 ± 38 days in group A and 59 ± 60 days in group B (P = 0.005). Average ± SD weight, height, and body surface area were 3.5 ± 0.7 kg, 52 ± 4 cm, and 0.22 ± 0.03 m², respectively, in group A, and 3.7 ± 1 kg, 53 ± 5 cm, and 0.23 ± 0.02 m², respectively, in group B (P = not significant [NS]). Male sex was predominant (55 vs. 58%, P = NS). Priming volume was 524 ± 67 mL (group A) and 337 ± 53 mL (group B) (P = 0.001). There were no statistical differences in hemoglobin at the start, during, and at the end of CPB, but group A required higher blood volume added to the prime (111 ± 33 vs. 93 ± 31 mL, P = 0.001). In group B, two surgical procedures were completed in total hemodilution. In group B, CPB time and aortic cross‐clamp time were shorter than in group A (106 ± 52 vs. 142 ± 78 min and 44 ± 31 vs. 64 ± 31 min, respectively, P = 0.001). There were 16 hospital deaths in group A and 4 in group B (P = 0.04). Durations of mechanical ventilation and intensive care unit stay were 5.3 ± 3.2 vs. 4.1 ± 3.2 days (P = 0.02) and 6.5 ± 4.9 vs. 5.1 ± 3 days (P = 0.03), respectively. There were significant differences in inotropic score (1083 ± 1175 vs. 682 ± 938, P = 0.04) and blood postoperative transfusion (153 ± 226 vs. 90 ± 61 mL, P = 0.04). Twenty‐seven patients in group A and 10 in group B presented with major adverse postoperative complications (P = 0.04). Use of neonatal oxygenators with low priming volume, associated with a miniaturized bypass circuit, seems to be a favorable strategy to decrease postoperative morbidity after cardiac surgery in neonates and infants.     

The Effect of Cardiopulmonary Bypass and Hypothermic Circulatory Arrest on Hepatic Histology in Newborn Animals: An Experimental Study

Still little is known about the effect of cardiac surgery on neonatal hepatic tissue. We examined the effect of cardiopulmonary bypass (CPB) and the effect of deep hypothermic circulatory arrest (DHCA) on neonatal hepatic tissue. Liver biopsies of neonatal piglets were taken after CPB (n = 4), after DHCA (n = 5), and after surgery without CPB (non‐CPB; n = 3). Additionally, findings were compared to those of control piglets (n = 9). The liver specimens were fixed, stained with hematoxylin and eosin, and scored regarding inflammatory reaction, hepatocellular edema, and apoptosis. Inflammation score of treated groups was higher than in control; CPB 2.5 ± 0.5, DHCA 1.6 ± 0.4, non‐CPB 1.2 ± 0.6, control 0.4 ± 0.3 (P < 0.001 CPB and DHCA vs. control; P < 0.05 non‐CPB vs. control). Hepatic cell edema was more evident after DHCA (score 2.0 ± 0.4 vs. 0.2 ± 0.3 in control and 0.6 ± 0.5 after CPB; P < 0.001 and P < 0.05, respectively). The highest apoptotic cell count was in the non‐CPB group (22.3 ± 6.3 vs. 11.4 ± 3.6 in control and 8.9 ± 5.4 after CPB; P < 0.05). The present study showed that (i) surgical trauma induces hepatic cell apoptosis; (ii) CPB increases hepatic inflammatory reaction; and (iii) DHCA amplifies hepatic cell edema.     

Effects of pulsatile and nonpulsatile perfusion on cerebral regional oxygen saturation and endothelin-1 in tetralogy of fallot infants

Although benefits of pulsatile flow during cardiopulmonary bypass (CPB) in pediatric heart surgery remain controversial and nonpulsatile CPB is still widely used in clinical cardiac surgery, pulsatile CPB must be reconsidered due to its physiologic features. In this study, we aimed to evaluate the effects of pulsatile perfusion (PP) and nonpulsatile perfusion (NP) on cerebral regional oxygen saturation (rSO₂) and endothelin‐1 (ET‐1) in pediatric tetralogy of Fallot (TOF) patients undergoing open heart surgery with CPB. Forty pediatric patients were randomly divided into the PP group (n = 20) and the NP group (n = 20). Pulsatile patients used a modified roller pump during the cross‐clamp period in CPB, while NP patients used a roller pump with continuous flat flow perfusion. The subjects were monitored for rSO₂ from the beginning of the operation until 6 h after returning to the intensive care unit (ICU). We also monitored the hemodynamic status and ET‐1 concentration and plasma free hemoglobin (PFH) in blood samples of all patients over time. Effective PP was monitored in PP patients, and pulse pressure was significantly higher in the PP group than in the NP group (P < 0.01). rSO₂ of the PP group was higher than that of the NP group (P < 0.01) during the cross‐clamp period, and this advantage of PP would be maintained until 2 h after patients returned to the ICU (P < 0.05). ET‐1 level in blood samples was lower at clamping off and CPB weaning and early ICU period in the PP group than in the NP group (P < 0.01), and ET‐1 concentration remained at a normal level after patients were transferred to the ICU 24 h in all patients. PFH levels in the PP group at pre‐clamp off and CPB weaned off were higher than those of the NP group (P < 0.05) in these cyanotic patients. PP can increase rSO₂ and improve microcirculation during cross‐clamping period in TOF pediatric patients, while PP resulted in more severe hemolysis in these cyanotic patients than NP.     

Hemoglobin Trends in Isolated Coronary Artery Bypass Grafting Performed Off‐Pump and With Standard and Mini Circuits

The comparison of hemodilution at the end of surgery is of limited use as it represents only a snapshot of a dynamic phenomenon. This study was undertaken to compare the perioperative hemoglobin curves of isolated coronary artery bypass grafting performed with minimized extracorporeal circulation, traditional cardiopulmonary bypass, and off‐pump technique. The propensity score method was used to select three groups of patients, homogenous regarding preoperative and operative data, who underwent isolated coronary artery bypass grafting. A generalized linear mixed model was used for estimating differences in perioperative hemoglobin trends among groups. The three groups were each composed of 50 patients with no differences in demographic data, preoperative risk profile, preoperative hemoglobin, or type of surgery. There was no significant difference in major postoperative complications. The pattern of the hemodilution curves was similar in patients operated with mini‐circuit and off‐pump technique (P > 005). Mini‐circuit led to a 3.1 ± 11.9% hemoglobin reduction, which was similar to the off‐pump group (1.6 ± 8.9%, P = 0.99 at ANOVA) and significantly different from the standard extracorporeal circuit group (16.0 ± 10.3%, P < 0.001 at ANOVA). The generalized linear mixed model determined that the standard circuit was the only independent predictor for increased hemodilution. Its effect on hemodilution was time‐dependent and the slope of the hemoglobin curve was more pronounced between systemic heparinization and the end of surgery. Perioperative hemoglobin trends of patients who underwent myocardial revascularization with mini‐circuit were similar to those of off‐pump surgery and significantly less pronounced than those of standard extracorporeal circulation.     

The Benefits of High‐flow Management in Children With Pulmonary Atresia

The high‐flow management of cardiopulmonary bypass (CPB; ≥2.4 L/min/m²) is a standard strategy used at this institute for children with pulmonary atresia (PA) due to a fear that the blood flow may be diverted by the major/minor aortopulmonary‐collateral‐arteries and hypervascularization due to long‐term hypoxia. The purpose of this study was to describe the validity of high‐flow management in children with PA. The CPB records of 23 children with PA who underwent a definitive biventricular repair between Feb 2006 and Nov 2008 were retrospectively reviewed. The mean age at the operation was 33 ± 22 months. The blood‐pressure during bypass was controlled with the same protocol. The mean cooling‐temperature was 28.4 ± 3.7°C. The mean minimum hematocrit was 25.0 ± 3.4%. The mean maximum bypass flow index at the initiation, the mean maximum flow index during aortic cross‐clamping, the mean minimum flow index during aortic cross‐clamping, and the mean maximum flow index after rewarming were 3.1 ± 0.5, 3.1 ± 0.5, 2.6 ± 0.4, and 3.2 ± 0.4 L/min/m², respectively. The higher bypass flow indexes significantly correlated with the lower serum lactate levels. The lowest oxygen delivery during CPB had significant influences on the urine output during bypass (R = 0.547, P = 0.007), the serum lactate levels at the end of CPB (R = ?0.442, P = 0.035), and the postoperative thoracic effusion (R = ?0.459, P = 0.028). A bypass flow index of 2.4 L/min/m² may not be sufficient and the maximum requirement of bypass flow index may be 3.2 L/min/m² or more in this patient population.     

The effects of aprotinin and tranexamic acid on thrombin generation and fibrinolytic response after cardiac surgery

Background: Thrombin formation during cardiac surgery could result in disordered hemostasis and thrombosis. The aim of the study was to examine the effects of aprotinin and tranexamic acid on thrombin generation and fibrinolytic activity in patients undergoing cardiac surgery. Methods: Data were collected prospectively from 60 patients undergoing coronary artery bypass grafting using cardiopulmonary bypass (CPB). In a randomized sequence, 20 patients received aprotinin, 20 patients received tranexamic acid, and in 20 patients placebo was used. Results: Significant thrombin activity was found in all the studied patients. Thrombin generation was less in the aprotinin group than in the tranexamic acid and the placebo group (thrombin/anti‐thrombin III complexes 33.7 ± 3.6, 53.6 ± 7.0 and 44.2 ± 5.3 µg/l 2 h after CPB and F1 + 2 fragment 1.50 ± 0.10, 2.37 ± 0.37 and 2.04 ± 0.20 nmol/l 6 h after surgery, respectively). The inhibition of fibrinolysis was significant with both anti‐fibrinolytic drugs (d ‐dimers 0.427 ± 0.032, 0.394 ± 0.039 and 2.808 ± 0.037 mg/l 2 h after CPB, respectively). The generation of d ‐dimers was inhibited until 16 h after CPB in the aprotinin group. The plasminogen activation was significantly less in the aprotinin group (plasmin/anti‐plasmin complexes 0.884 ± 0.095, 2.764 ± 0.254 and 1.574 ± 0.185 mg/l 2 h after CPB, respectively). Conclusion: Thrombin formation is inevitable in coronary artery bypass surgery when CPB is used. The suppression of fibrinolytic activity, either with aprotinin or with tranexamic acid interferes with the hemostatic balance as evaluated by biochemical markers. Further investigations are needed to define the role of hemostatic activation in ischemic complications associated with cardiac surgery.     

Five‐Year Experience With Mini‐Volume Priming in Infants ≤5 kg: Safety of Significantly Smaller Transfusion Volumes

Reducing the cardiopulmonary bypass (CPB) priming volume in congenital cardiac surgery is important because it is associated with fewer transfusions. This retrospective study was designed to compare safety and transfusion volumes between the mini‐volume priming (MP) and conventional priming (CP) methods. Between 2007 and 2012, congenital heart surgery using CPB was performed on 480 infants (≤5 kg): the MP method was used in 331 infants (MP group, 69.0%), and the CP method was used in 149 infants (CP group, 31.0%). In the MP group, narrow‐caliber (3/16″) tubing was used, and the pump heads were vertically aligned to shorten the tubing lengths. The smallest possible oxygenators and hemofilters were used, and vacuum drainage was applied. Ultrafiltration was vigorously applied during CPB to avoid excessive hemodilution. The mean age and body weight of the patients were 48 ± 41 (0–306) days and 3.8 ± 0.8 (1.3–5.0) kg, respectively. The total priming and transfusion volumes during CPB were lower in the MP group than in the CP group (141 ± 24 mL vs. 292 ± 50 mL, P < 0.001, and 82 ± 40 mL vs. 162 ± 82 mL, P < 0.001, respectively). In the MP group, the smallest priming volume was 110 mL. However, there was no significant difference in the lowest hematocrit level during CPB between the two groups (22 ± 3% vs. 22 ± 3%, P = 0.724). The incidence of postoperative neurological complications was not significantly different between the MP and CP groups (1.8% vs. 2.7%, P = 0.509). After adjustment for the Risk Adjustment for Congenital Heart Surgery category, body surface area, and age, MP was not an independent risk factor of postoperative neurological complications or early mortality (P = 0.213 and P = 0.467, respectively). The MP method reduced the priming volume to approximately 140 mL without increasing the risk of morbidity or mortality in infants ≤5 kg. The total transfusion volume during CPB was reduced by 50% without compromising hematocrit levels. We recommend the use of mini‐volume priming, which is a safe and effective method for reducing transfusion volumes.     

An increase in macrophage migration inhibitory factor release in patients with cardiopulmonary bypass surgery

To determine the macrophage migration inhibitory factor (MIF) responses to cardiopulmonary bypass (CPB) surgery as well as to investigate their roles in predicting patient outcome, a prospective, observational, pilot study was performed. Thirty patients undergoing cardiovascular surgery with CPB received 10 mg/kg betamethasone immediately before the CPB. Ten normal healthy volunteers served as control subjects. Blood samples were serially obtained for 24 h and assayed for MIF, cortisol, and tumor necrosis factor α (TNF-α). TNF-α release could not be detected during the study period. Compared with both the control and baseline values, the MIF and cortisol levels were elevated before CPB and peaked at the end of CPB (57.5 ± 4.8 ng/ml, P < 0.0001), and at the end of the surgery (507.7 ± 44.1 nmol/l, P < 0.0001), respectively. Peak MIF levels correlated with aortic cross-clamp time (r ² = 0.183, P = 0.0182, n = 30), but did not show a significant correlation with peak cortisol levels. The levels of MIF tended to be 40%–50% higher during CPB in patients with longer intensive care unit (ICU) stays and in those with organ dysfunction than in those with short ICU stays and no organ dysfunction. All patients were discharged from the ICU. In conclusion, our findings demonstrate that MIF production occurs in patients with CPB surgery. When high-dose steroids are administered, high MIF levels were found to only slightly affect the patient morbidity and outcome after CPB surgery. Received: August 17, 1999 / Accepted: March 24, 2000     

Normothermic cardiopulmonary bypass and cardioplegia reduce inotropic requirements and creatine kinase-MB after coronary artery bypass graft surgery

Purpose To determine whether normothermic cardiopulmonary bypass (CPB) and cardioplegia preserve myocardial function, reduce inotropic requirements, and reduce markers of myocardial ischemia following coronary artery bypass graft surgery (CABG). Methods We retrospectively reviewed the charts of 171 consecutive patients undergoing elective CABG by a single surgeon from April 1994 to December 1995. Hypothermic CPB with intermittent cold cardioplegia was used in 83 patients and normothermic CPB with intermittent warm cardioplegia in 88 patients. Demographic, surgical, hemodynamic, and inotropic requirements and laboratory data were reviewed. Results The duration of CPB was significantly shorter in the normothermic group (113±27vs 90±21 min;P<0.0001). After CPB the cardiac index was similar between groups, but significantly larger doses of both dopamine and dobutamine were required (8vs 5μg·kg⁻¹·min⁻¹,P<0.0001), and significantly more patients required norepinephrine administration in the hypothermic group (18%vs 6%;P=0.01). Postoperative peak values of creatine kinase MB fraction (CK-MB) were significantly lower in the normothermic group (80±60vs 55±54 IU·I⁻¹;P<0.0001). Conclusion Normothermic CPB and cardioplegia reduce inotropic requirements and CK-MB following CABG.     

Effect of a Miniaturized Cardiopulmonary Bypass System on the Inflammatory Response and Cardiac Function in Neonatal Piglets

The cognitive impairment and hemodynamic instability after neonatal cardiac surgery with cardiopulmonary bypass (CPB) might be exacerbated by hemodilution. Therefore, this study investigated the impact of different bloodless prime volumes on the hemodynamics and the inflammatory response by a miniaturized CPB system in neonatal piglets. The bypass circuit consisted of a Capiox RX05 (Capiox Baby RX, Terumo Corp., Tokyo, Japan) oxygenator and 3/16 internal diameter arterial and venous polyvinyl chloride tubing lines, with a minimum 75 mL prime volume. Twelve 1‐week‐old piglets were placed on a mild hypothermic CPB (32°C) at 120 mL/kg/min for 2 h. The animals were divided into two groups, based on the volume of the prime solution. The priming volume was 75 mL in Group I and 175 mL in Group II. No blood transfusions were performed, and no inotropic or vasoactive drugs were used. The interleukin‐6 (IL‐6) and thrombin‐antithrombin (TAT) complex levels, as well as right ventricular and pulmonary functions, were measured before and after CPB. Group I had low levels of IL‐6 and TAT immediately after CPB (4370 ± 2346 vs. 9058 ± 2307 pg/mL, P < 0.01 and 9.9 ± 7.7 vs. 25.1 ± 8.8 ng/mL, P < 0.01, respectively). Group I had significantly improved cardiopulmonary function, cardiac index (0.22 ± 0.03 vs. 0.11 ± 0.05 L/kg/min, P < 0.001), and pulmonary vascular resistance index (7366 ± 2860 vs. 28 620 ± 15 552 dynes/cm⁵/kg, P < 0.01) compared with Group II. The miniaturized bloodless prime circuit for neonatal CPB demonstrated that the influence of hemodilution can reduce the subsequent inflammatory response. In addition, a low prime volume could therefore be particularly effective for attenuating pulmonary vascular resistance and right ventricular dysfunction in neonates.     

Creatinine,Neutrophil Gelatinase‐Associated Lipocalin,and Cystatin C in Determining Acute Kidney Injury After Heart Operations Using Cardiopulmonary Bypass

Acute kidney injury (AKI) represents frequent complication after cardiac surgery using cardiopulmonary bypass (CPB). In the hope to enhance earlier more reliable characterization of AKI, we tested the utility of neutrophil gelatinase‐associated lipocalin (NGAL) and cystatin C (CysC) in addition to standard creatinine for early determination of AKI after cardiac surgery using CPB. Forty‐one patients met the inclusion criteria. Arterial blood samples collected after induction of general anesthesia were used as baseline, further sampling occurred at CPB termination, 2 h after CPB, on the first and second day after surgery. According to AKIN classification 18 patients (44%) developed AKI (AKI1‐2 groups) and 23 (56%) did not (non‐AKI group). Groups were similar regarding demographics and operative characteristics. CysC levels differed already preoperatively (non‐AKI vs. AKI2; P = 0.045; AKI1 vs. AKI2; P = 0.011), while postoperatively AKI2 group differed on the first day and AKI1 on the second regarding non‐AKI group (P = 0.004; P = 0.021, respectively). NGAL and creatinine showed significant difference already 2 h after CPB between groups AKI2 and non‐AKI and later on the first postoperative day between groups AKI1 and AKI2 (P = 0.028; P = 0.014, respectively). This study shows similar performance of early plasma creatinine and NGAL in patients with preserved preoperative renal function. It demonstrates that creatinine, as well as NGAL, differentiate subsets of patients developing AKI of clinically more advanced grade early after 2 h, also when used single and uncombined.     

Cystatin C: influence of perfusion and myocardial injury on early (<24 h) renal function after pediatric cardiac surgery

Background: Cardiopulmonary bypass (CPB)‐associated renal dysfunction following cardiac surgery is well recognized. In patients with renal disease, cystatin C has emerged as a new biomarker which in contrast to creatinine (Cr) is sensitive to minor changes in glomerular filtration rate (GFR). Aim: We utilized cystatin C to investigate the association of CPB perfusion parameters with acute renal injury after pediatric cardiac surgery. Methods: Twenty children, aged 4–58 months (AVSD, n = 7; VSD, n = 9; and ASD, n = 4), were prospectively studied. Glomerular filtration rate was quantified postoperatively by creatinine clearance (first and second 12‐h periods; CrCl_0–12 and CrCl_12–24). Serum cystatin C and Cr were measured preoperatively and on days 0–3. Recorded CPB parameters included bypass duration (BP), perfusion pressure (PP), lowest pump flow (Q_min), lowest hematocrit, and corresponding lowest oxygen delivery (DO_{2 min}). Myocardial injury was determined by troponin‐I. Results: Postoperatively, GFR remained unchanged (CrCl_0–12 63.6 ± 37.0 vs CrCl_12–24 65.1 ± 27.5; P = 0.51) and only correlated with cystatin C (CrCl_0–12 vs cystatin C_Day0 [r = 0.58, P = 0.018] and Cr_Day0 [r = 0.09, P = 0.735]). Cr and cystatin C increased postoperatively to peak on days 2 and 3, respectively (Cr_PreOp 31 ± 6.9 vs Cr_Day2 36.9 ± 12.2, P = 0.03; cystatin C_Day0 0.83 ± 0.27 vs cystatin C_Day3 1.45 ± 0.53, P = 0.02). Increased cystatin C was significantly associated with BP (P = 0.001), mean PP (P = 0.029), Q_min (P = 0.005), troponin‐I (P < 0.001), and DO_2min <300 ml·min^?1·m^?2 (P = 0.007). Receiver–operator cutoff >1.044 mg·l^?1 for cystatin C exhibited 100% sensitivity and 67% specificity for detecting renal dysfunction, defined as GFR <55 ml·min^?1·1.73 m^?2. Conclusions: Cystatin C is a sensitive marker of early renal dysfunction following pediatric heart surgery. Variations in bypass parameters, myocardial injury, and ultimately critical oxygen delivery are significantly associated with the degree of renal impairment.     

Less Platelet Damage in the Curved Vane Centrifugal Pump: A Comparative Study with the Roller Pump in Open Heart Surgery

Abstract: The centrifugal pump with the curved vane (Lifestream Centrifugal Pump [LCP]) was applied to cardiopulmonary bypass (CPB) in 10 patients who underwent elective coronary artery bypass grafting. Serum hemoglobin levels, platelet counts, and serum β–thromboglogulin (β–TG) levels were measured during CPB. The results were compared with those for a comparative roller pump (RP) group (n = 10). There was no difference in CPB time between LCP (112 ± 22 min) and RP (121 ± 22 min) groups. Serum β–TG levels (ng/ml) were lower in the LCP group than in the RP group (34 ± 9 vs. 101 ± 80, 5 min; 81 ± 33 vs. 236 ± 112, 30 min; 120 ± 53 vs. 314 ± 100, 60 min after initiation of CPB; p < 0. 05). There were no significant differences in hemolysis and platelet depletion. The LCP showed excellent hemodynamic performance with less blood trauma in clinical application to open heart surgery.     

Carotid Artery Doppler Flow Pattern After Deep Hypothermic Circulatory Arrest in Neonatal Piglets

The mechanisms of cerebral injury after cardiac surgery in neonates are not clear. The aim of the study was the analysis of flow changes in the carotid artery of neonatal piglets after deep hypothermic circulatory arrest (DHCA). Eight neonatal piglets were connected to cardiopulmonary bypass (CPB) and underwent (i) cooling to 18°C core temperature within 30 min, (ii) DHCA for 90 min, and finally (iii) rewarming to 37°C after cross‐clamp release (60 min of reperfusion). The blood flow was measured in the left carotid artery by an ultrasonic flow probe before CPB (baseline; T₀), immediately after termination of reperfusion on CPB (T₁), 30 min later (T₂), and 60 min later (T₃). Additionally, the pulsatility index and the resistance index were calculated and compared. Finally, the relationship between the carotid artery flow and the corresponding pressure at each time‐point was compared. After termination of CPB (T₁), the mean carotid artery flow was reduced from 45.26 ± 2.58 mL/min at baseline to 23.29 ± 2.58 mL/min (P < 0.001) and remained reduced 30 and 60 min later (P < 0.001 vs. baseline). Both the pulsatility index and the resistance index were increased after termination of reperfusion, with the maximum occurring 30 min after CPB end. In conclusion, the carotid artery Doppler flow in neonatal piglets was reduced after DHCA, while the indices of pulsatility and resistance increased.