Coagulation Profile of Neonates Undergoing Arterial Switch Surgery With Crystalloid Priming of the Cardiopulmonary Bypass Circuit.

OBJECTIVES: The aim was to evaluate changes in the coagulation profile of cyanotic neonates, to analyze the effects of cardiopulmonary bypass (CPB) with crystalloid priming on their coagulation status, and to determine factors predicting a requirement for hemostasis-derived transfusion. DESIGN: Retrospective cohort. SETTING: Single-center, tertiary academic hospital. PARTICIPANTS: In total, 100 consecutive neonates who underwent arterial switch surgery between December 2014 and June 2020. INTERVENTIONS: Rotational thromboelastometry (ROTEM) and coagulation parameters before surgery and before termination of CPB were evaluated. Transfusion of platelets, fresh frozen plasma, and fibrinogen, defined as hemostasis-derived transfusion (HD transfusion), were determined. Patients with and without HD transfusion were compared to identify predictors. MEASUREMENTS AND MAIN RESULTS: After CPB, fibrinogen was reduced by 24.5% (interquartile range [IQR] 8.9-32.1) to 201 mg/dL (IQR 172-249), resulting in a reduction of FIBTEM A10 by 20% (1.8-33.3) to 8 mm (6-11). The platelet count decreased by a median of 47.2% (25.6-61.3) to 162 × 103/µL (119-215). However, the median fibrinogen concentration and platelet count remained within normal range. Neonates with abnormal ROTEM results were more likely to receive HD transfusions. The HD transfusions were more likely with lower preoperative FIBTEM maximum clot firmness values (p = 0.031), lower hemoglobin concentrations at termination of CPB (p = 0.02), and longer CPB duration (p = 0.017). Perioperative hemostasis without any HD transfusion was achieved in 64 neonates. CONCLUSIONS: Guidance from ROTEM analyses facilitates hemostasis management after neonatal CPB. Circuit miniaturization with transfusion-free CPB is associated with acceptable changes in ROTEM in most patients, and allows sufficient hemostasis without any HD transfusions in most patients.

Acute Kidney Injury After Neonatal Aortic Arch Surgery: Deep Hypothermic Circulatory Arrest Versus Moderate Hypothermia With Distal Aortic Perfusion.

BACKGROUND: Acute kidney injury (AKI) is a common complication observed after neonatal aortic arch repair. We studied its incidence after procedures carried out using deep hypothermic circulatory arrest (DHCA) versus moderate hypothermia with distal aortic perfusion (MHDP), usually through the common femoral artery. In both groups, continuous regional cerebral perfusion (RCP) was used during the time required for aortic arch repair. METHODS: A total of 125 neonates underwent aortic arch repair. Between 2007 and 2012, DHCA with RCP was used in 51 neonates. From 2013 to 2019, MHDP with RCP was performed on 74 newborns. Operative complexity was similar in both periods. Acute kidney injury was defined as a significant elevation of serum creatinine and was classified according to the neonatal modified n-KDIGO (neonatal Kidney Disease: Improving Global Outcomes) stages 1 to 3 (Kidney Disease Improving: Global Outcomes). RESULTS: Acute kidney injury was observed in a total of 68 patients (68/125: 54.4%). In the majority (44/68: 64.7%), n-KDIGO stage 1 occurred. Stage 2 (n = 14) and stage 3 (n = 10) were observed more frequently after DHCA versus MHDP: 29.4% (15/51) versus 12.2% (9/74), P = .02. At cardiopulmonary bypass end, lactate levels were significantly higher (P = .001) after DHCA: 3.4 (2.9-4.3) mmol/L compared to 2.7 (2.3-3.7) mmol/L after MHDP. Early mortality was 12% (15/125) in the entire cohort. It was 17.6% (9/51) after DHCA versus 8.1% (6/74) after MHDP, however not statistically significant (P = .16). CONCLUSION: Mild (stage 1) AKI occurred frequently after neonatal aortic arch repair. The use of MHDP was associated with a significantly lower incidence of moderate (stage 2) and severe (stage 3) AKI forms.

Fast-track extubation after cardiac surgery in infants: Tug-of-war between performance and reimbursement?

OBJECTIVES: To compare the safety and resource-efficacy of the fast-track (FT) concept (extubation ≤8 hours after surgery) versus the conventional approach (non-FT, >8 hours postoperatively) in infants undergoing open-heart surgery. METHODS: Infants <7 kg operated on cardiopulmonary bypass between 2014 and 2018 were analyzed. Propensity score matching (1:1) was performed for group comparison (FT vs non-FT). Intensive care unit (ICU) personnel use and unit performance were evaluated. Postoperative outcome and reimbursement based on German diagnosis-related groups were compared. RESULTS: Of 717 infants (median age: 4 months, Society of Thoracic Surgeons-European Association for Cardio-Thoracic Surgery mortality score: 0.1-4), FT extubation was achieved in 182 infants (25%). After matching, 123 pairs (FT vs non-FT) were formed without significant differences in baseline characteristics. FT versus non-FT showed a significantly shorter ICU stay (in days): 1.8 (0.9-2.8) versus 4.2 (1.9-6.4), P < .01, and postoperative length of stay (in days): 7 (6-10) versus 10 (7-15.5), P < .01; significantly lower postoperative transfusion rates: 61.3% versus 77%, P < .01; and tendency toward lower early mortality: 0% versus 2.8%, P = .08. Reintubation rate did not differ between the groups (P = .7). Despite a decrease in personnel capacity (2014 vs 2018), the unit performance was maintained. The mean case-mix-index of FT versus non-FT was 8.56 ± 6.08 versus 11.77 ± 12.10 (P < .01), resulting in 27% less reimbursement in the FT group. CONCLUSIONS: FT concept can be performed safely and resource-effectively in infants undergoing open-heart surgery. Since German diagnosis-related group systems reimburse costs, not performance, there is little incentive to avoid prolonged mechanical ventilation. Greater ICU turnover rates and excellent postoperative outcomes are not rewarded adequately.

Cardiopulmonary Bypass Strategy to Facilitate Transfusion-Free Congenital Heart Surgery in Neonates and Infants.

Priming the cardiopulmonary bypass (CPB) circuit without the addition of homologous blood constitutes the basis of blood-saving strategies in open-heart surgery. For low-weight patients, in particular neonates and infants, this implies avoidance of excessive hemodilution during extracorporeal circulation. The circuit has to be miniaturized and tubing must be cut as short as possible to reduce the priming volume to prevent unacceptable hemodilution with initiating CPB. During perfusion, measures should be taken to prevent blood loss from the primary circuit to avoid replacement by additional volume. Favorable factors such as mild hypothermia/normothermia and high heparin concentrations during extracorporeal circulation promote earlier hemostasis after coming off bypass.Lower mortality score, first chest entry, higher hemoglobin concentration before going on bypass, and shorter CPB duration support transfusion-free CPB procedure. Reduced postoperative morbidity and mortality were observed when CPB was performed without blood transfusion. In our experience, this can be achieved in at least 70% of CPBs, even in low-weight patients.Bloodless CPB circuit priming should become a widespread reality, even in neonates and young infants, in any open-heart procedure.

Asanguineous Cardiopulmonary Bypass in Infants: Impact on Postoperative Mortality and Morbidity.

BACKGROUND: We routinely start cardiopulmonary bypass (CPB) for pediatric congenital heart surgery without homologous blood, due to circuit miniaturization, and blood-saving measures. Blood transfusion is applied if hemoglobin concentration falls under 8 g/dL, or it is postponed to after coming off bypass or after operation. How this strategy impacts on postoperative mortality and morbidity, in infants weighing ≤ 7 kg? METHODS: Six-hundred fifteen open-heart procedures performed from January 2014 to June 2018 were selected. One-hundred sixty-three patients (26.5%) were transfused on CPB (group 1), while 452 (73.5%) patients were not transfused on CPB (group 2). Operative risk and complexity were similar in both groups. Postoperative mortality and morbidity were compared. Multiple logistic regression was used to detect factors independently associated with outcome. RESULTS: Observed mortality in nontransfused group (0.7% = 3/452) was significantly lower than expected (4.2% = 19/452): p = 0.0007, and much lower than in transfused group (6.7% = 11/163): p < 0.0001. CPB transfusion (p = 0.001) was independently associated with mortality, either acting as the sole factor or in combination with the Society of Thoracic Surgeons morbidity score (p = 0.013). Patients not transfused during CPB required less frequently vasoactive inotropic drugs (p = 0.011) and duration of their mechanical ventilation was shorter (93 ± 134 hours) than for transfused patients (142 ± 170 hours): p = 0.0003. CPB transfusion was an independent determinant factor for morbidity (p = 0.05), together with body weight (p < 0.0001), vasoactive inotropic score (p < 0.0001), CPB duration (p = 0.001), and postoperative transfusion (p = 0.009). CONCLUSION: The strategy of transfusion-free CPB course, feasible in most patients ≤ 7kg, was associated with improved outcome. Asanguineous priming of CPB circuit should become standard, even in neonates and infants.

Bilateral Pulmonary Artery Banding before Norwood Procedure: Survival of High-Risk Patients.

BACKGROUND: This study reports midterm results of high-risk patients with hypoplastic left ventricle treated with initial bilateral pulmonary artery banding (PAB) before secondary Norwood procedure (NP). METHODS: Retrospective study of 17 patients admitted between July 2012 and February 2017 who underwent this treatment strategy because diagnosis or clinical status was associated with high risk for NP. Survival was compared with that of patients who underwent primary NP. RESULTS: Mean Aristotle comprehensive complexity score for NP would have been 19.7 ± 2.6. Risk factors included obstructed pulmonary venous return (n = 9), body weight < 2.5 kg (n = 7), total anomalous pulmonary venous connection (n = 3), and necrotizing enterocolitis (n = 1). Ten patients had a score ≥ 19.5. Early survival after PAB was 82.4% (14/17). NP was performed in 14 patients after improvement of clinical condition at a median age of 56 days and a weight ≥2,500 g. There was no 30-day mortality, but one interstage death. One patient died later after Glenn operation. One-year survival after primary PAB followed by NP was 70.6 ± 11.1%. During the same period, 35 patients with overall lower risk factors underwent primary NP; early postoperative survival and 1-year survival were 88.6 ± 5.4% and 68.6 ± 7.8%, respectively. There was no significant difference in survival between the two groups (p = 0.83) despite higher risk in the secondary Norwood group (p <0.0001). CONCLUSIONS: PAB before NP in high-risk patients constituted salvage management. Primary PAB provided enough time for stabilization and control of most risk factors. It allowed midterm survival equivalent to the survival after primary NP in lower risk neonates.

Bloodless priming of the cardiopulmonary bypass circuit: determinants of successful transfusion-free operation in neonates and infants with a maximum body weight of 7 kg.

We currently perform open-heart procedures using bloodless priming of cardiopulmonary bypass circuits regardless of a patient's body weight. This study presents results of this blood-saving approach in neonates and infants with a body weight of up to 7 kg. It tests with multivariate analysis factors that affect perioperative transfusion. A total of 498 open-heart procedures were carried out in the period 2014-2016 and were analysed. Priming volume ranged from 73 ml for patients weighing up to 2.5 kg to 110 ml for those weighing over 5 kg. Transfusion threshold during cardiopulmonary bypass was 8 g/dl of haemoglobin concentration. Transfusion factors were first analysed individually. Variables with a p-value lower than 0.2 underwent logistic regression. Extracorporeal circulation was conducted without transfusion of blood in 335 procedures - that is, 67% of cases. Transfusion-free operation was achieved in 136 patients (27%) and was more frequently observed after arterial switch operation and ventricular septal defect repair (12/18=66.7%). It was never observed after Norwood procedure (0/33=0%). Lower mortality score (p=0.001), anaesthesia provided by a certain physician (p=0.006), first chest entry (p=0.013), and higher haemoglobin concentration before going on bypass (p=0.013) supported transfusion-free operation. Early postoperative mortality was 4.4% (22/498). It was lower than expected (6.4%: 32/498). In conclusion, by adjusting the circuit, cardiopulmonary bypass could be conducted without donor blood in majority of patients, regardless of body weight. Transfusion-free open-heart surgery in neonates and infants requires team cooperation. It was more often achieved in procedures with lower mortality score.

Incidence and echocardiographic predictors of early postoperative right ventricular dysfunction following left ventricular assist implantation in paediatric patients.

OBJECTIVES: Left ventricular assist device implantation is an established therapy for paediatric patients with end-stage heart failure. Early right ventricular dysfunction (RVD) after implantation still remains a challenge in the postoperative period. This study sought to determine the incidence of RVD and to identify echocardiographic predictors of RVD in paediatric patients, as well describing associated clinical outcome. METHODS: Prospectively collected preoperative echocardiographic, haemodynamic, demographic and biochemical data from 48 patients scheduled for left ventricular assist device implantation were evaluated. Incidence of high central venous pressure, decreased central venous saturation, high inotropic support requirements or need for mechanical support of the right ventricle during the first 48 h after implantation were used to define RVD. Echocardiographic assessments of right ventricular geometry, function using linear dimensions, areas and tricuspid annular plane systolic excursion (TAPSE) were performed preoperatively and the relative relationships between these parameters were evaluated. RESULTS: We included 48 consecutive paediatric patients (median age 5 years, range 0-17; median weight 15.9 kg, range 3.6-91). According to our criteria, 24 (50%) patients developed RVD. TAPSE as the parameter for assessment of longitudinal systolic function was significantly lower in this group (P = 0.01). The difference became even more pronounced after normalization to the RV end-diastolic diameter in long axis with P = 0.003. The odds ratio for patients with TAPSE/RV end-diastolic diameter in long axis <17.1% to develop RVD was 7.7 (P = 0.002). CONCLUSIONS: RVD occurs frequently in paediatric patients after left ventricular assist device. TAPSE, normalized to the RV end-diastolic diameter, may help to identify patients at risk for RVD. The predictive value of this parameter supports decision making to plan for adequate pharmacological support or consider early upgrading to mechanical RV support.

Additional veno-venous gas exchange as a problem-solving strategy for an oxygenator not transferring oxygen in paediatric cardiopulmonary bypass.

OBJECTIVES: Oxygenator failure during cardiopulmonary bypass constitutes a life-threatening event, especially when perfusion is conducted under normothermia. An alternative solution to emergency oxygenator changeover is described. METHODS: A supplementary oxygenator is added in the venous line without interrupting perfusion. De-airing is achieved through the cardiotomy reservoir. Oxygen supply is adapted to ensure physiologic partial oxygen pressure. RESULTS: On 5 occasions in the past 4 years, Capiox Baby FX 05 oxygenator (n = 4) and Capiox FX15 (n = 1) failed to exchange blood gases after bypass run ranging from 290 min to 563 min. Hypoxia ensued with partial oxygen pressure values of 49-79 mmHg with a fraction of inspired oxygen of 1. An additional veno-venous Terumo Capiox FX 05 oxygenator immediately improved oxygenation with resulting partial oxygen pressure increasing to at least 291 mmHg. CONCLUSIONS: An additional veno-venous oxygenator effectively corrects failing oxygenator during cardiopulmonary bypass. The method does not require circulation arrest. It does not carry the risk of air embolism. It can be carried out without any help from a second perfusionist or member of operation team.

Complex Cardiac Surgery on Patients with a Body Weight of Less Than 5 kg without Donor Blood Transfusion.

Performing safe cardiac surgery in neonates or infants whose parents are Jehovah's Witnesses is only possible in a coordinated team approach. An unconditional prerequisite is a cardiopulmonary bypass (CPB) circuit with a very low priming volume to minimize hemodilution. In the past decade, we have developed a functional blood-sparing approach at our institution. The extracorporeal circuit was miniaturized. This had to be recently adapted, faced with a challenge associated with the switch to high-volume crystalloid cardioplegia. A filtration circuit was added. Here, we report an open heart surgery on three consecutive children of Jehovah's Witness parents with a body weight of 2.7, 4.5, and 4.8 kg, respectively. Procedures consisted of one arterial switch operation and two repairs of complete atrioventricular septal defects. Our static priming volume of less than 90 mL resulted in a nadir hematocrit during CPB of 27.7% (Hb 8.9 g/dL) in a patient which happened to have the lowest body weight of 2.7 kg. The two other patients had their lowest hematocrit at 31.4% (Hb 10.2 g/dL). The three children could be treated without any kind of transfusion of blood which had left the circulation or its extensions, in accordance with the parents' wishes, and enjoy favorable outcomes without transfusion of blood products during their entire hospital stay.

Hypothermia During Cardiopulmonary Bypass Increases Need for Inotropic Support but Does Not Impact Inflammation in Children Undergoing Surgical Ventricular Septal Defect Closure.

Minimizing the systemic inflammatory response caused by cardiopulmonary bypass is a major concern. It has been suggested that the perfusion temperature affects the inflammatory response. The aim of this prospective study was to compare the effects of moderate hypothermia (32°C) and normothermia (36°C) during cardiopulmonary bypass on markers of the inflammatory response and clinical outcomes (time on ventilator) after surgical closure of ventricular septal defects. During surgical closure of ventricular septal defects under cardiopulmonary bypass, 20 children (median age 4.9 months, range 2.3-38 months; median weight 7.2 kg, range 5.2-11.7 kg) were randomized to a perfusion temperature of either 32°C (Group 1, n = 10) or 36°C (Group 2, n = 10). The clinical data and blood samples were collected before cardiopulmonary bypass, directly after aortic cross-clamp release, and 4 and 24 h after weaning from cardiopulmonary bypass. Time on ventilation as primary outcome did not differ between the two groups. Other clinical outcome parameters like fluid balance or length of stay in the intensive care were also similar in the two groups. Compared with Group 2, Group 1 needed significantly higher and longer inotropic support (P < 0.001). In Group 1, two infants had junctional ectopic tachycardia, and another had a pulmonary hypertensive crisis. Perfusion temperature did not influence cytokine release, organ injury, or coagulation. Cardiopulmonary bypass temperature does not influence time on ventilation or inflammatory marker release. However, in the present study, with a small patient cohort, patients operated under hypothermic bypass needed higher and longer inotropic support. The use of hypothermic cardiopulmonary bypass in infants and children should be approached with care.

Spinal cord ischemia after thoracic stent-grafting: causes apart from intercostal artery coverage.

BACKGROUND: Examination of a large collective combined with individual case analyses may give new insights into mechanisms and prevention of spinal cord ischemia (SCI) after thoracic endovascular repair. METHODS: In an 11-year period, stent-grafts were implanted in 406 patients for various aortic pathologic conditions. The mean age was 63 years (15-91 years) and 300 (74%) patients were men; 58 patients underwent staged thoracic stent-graft procedures. The length of aorta covered was between 75 and 584 mm (mean, 204 mm). Thoracoabdominal branched or fenestrated stent-grafts were implanted in 11 patients. The left subclavian artery was occluded in 161 patients (39%); this occurred in half of them (n = 78) after protective revascularization. Prophylactic cerebrospinal fluid (CSF) drainage was used selectively in 4 cases; no neuromonitoring was used. RESULTS: The incidence of SCI was 2.7% (n = 11); 6 patients (1.5%) had major permanent deficits. Conditions that had a potential influence on SCI were analyzed. Statistical correlation was found for previous conventional or endovascular abdominal aortic aneurysm repair (odds ratio [OR], 4.8), coverage of the entire descending thoracic aorta (OR, 3.6), and implantation of thoracoabdominal branched and fenestrated stent-grafts (OR, 9.5). Individual analyses revealed other conditions that might have played a role, such as embolization into the segmental arteries, severe visceral ischemia, profound hemorrhagic shock, and heparin-induced thrombocytopenia. CONCLUSIONS: The incidence of SCI is unexpectedly low despite extensive sacrifice of intercostal arteries. Extended coverage of the thoracic and thoracoabdominal aorta seems to have a higher risk, but other factors may contribute to the individual disaster.

Right-to-left ventricular end-diastolic diameter ratio and prediction of right ventricular failure with continuous-flow left ventricular assist devices.

BACKGROUND: Left ventricular assist device (LVAD) implantation is an accepted therapy for patients with end-stage heart failure. Post-operative right ventricular failure (RVF) still remains a major cause of morbidity and mortality in these patients. This study sought to identify echocardiography parameters to select patients with high risk of RVF after LVAD implantation. METHODS: Prospectively collected pre-operative transesophageal echocardiography (TEE) and clinical data were evaluated in patients pre-selected for isolated LVAD or biventricular assist device (BiVAD) implantation. According to prevalence of RVF during the first post-operative 48 hours, patients were divided into those who developed RVF (isolated LVAD with RVF) and those who did not (isolated LVAD without RVF). Echocardiographic parameters for RV geometry, RV function, LV geometry, and the RV-to-LV end-diastolic diameter ratio (R/L ratio) were evaluated. For identification of the optimal cutoff of R/L ratio, receiver operating characteristics curves were constructed. RESULTS: An isolated LVAD was implanted in 115 patients and BiVAD in 22 patients. RVF developed in 15 patients (13%) after isolated LVAD implantation. The R/L ratio was markedly increased in the isolated LVAD with RVF and BiVAD groups compared with the isolated LVAD without RVF group. According to the receiving operating curve, the cutoff for the R/L ratio to predict RVF was 0.72. The odds ratio that RVF will develop is 11.4 in patients with an R/L ratio >0.72 (p = 0.0001). CONCLUSIONS: Increased R/L ratio successfully identifies patients with high risk of RVF after isolated LVAD implantation. Beyond standard measurements of RV function, the consideration of R/L ratio may be useful to improve risk stratification in patients before isolated LVAD implantation.

Regional differences in tissue oxygenation during cardiopulmonary bypass for correction of congenital heart disease in neonates and small infants: relevance of near-infrared spectroscopy.

OBJECTIVE: Cardiac surgery with cardiopulmonary bypass for correction of congenital heart disease in neonates and small infants is associated with considerable neurologic sequelae. We assessed the extent to which mixed venous oxygen saturation as a measure for adequacy of perfusion, reflects the oxygenation status of upper and lower body compartments. Moreover, we evaluated potential benefits of near-infrared spectroscopic monitoring of regional tissue oxygenation. METHODS: Twenty patients (body weight < 10 kg) undergoing open cardiac procedures with cardiopulmonary bypass were enrolled. Blood samples were obtained in parallel from inferior and superior caval vein cannulas and mixed venous line and assessed for venous oxygen saturation and lactate levels. Data were compared to simultaneously measured tissue oxygenation indices obtained by near-infrared spectroscopy from brain and lower limb. RESULTS: Venous oxygen saturation was lower and lactate concentration higher in blood from superior relative to inferior venous line. Mixed venous oxygen saturation correlated with venous oxygen saturation from inferior venous line and tissue oxygenation index of lower limb. No correlation was found between mixed venous oxygen saturation and venous oxygen saturation from superior venous line or cerebral tissue oxygenation index. CONCLUSION: In neonates and small infants undergoing cardiac surgery with cardiopulmonary bypass, considerable regional differences exist in venous oxygen saturation. Mixed venous oxygen saturation primarily represents lower-torso oxygen status but poorly reflects and systematically overestimates upper-body oxygenation. Near-infrared spectroscopy yields additional information on regional oxygenation and may be valuable in early and sensitive detection of regional malperfusion in critical organs such as the brain.

Detection of lower torso ischemia by near-infrared spectroscopy during cardiopulmonary bypass in a 6.8-kg infant with complex aortic anatomy.

Neonates and small infants with congenital heart disease and complex cardiac and vascular anatomy are particularly prone to episodes of complete or incomplete regional ischemia during cardiopulmonary bypass. These episodes may result either from inhomogeneous distribution of arterial blood flow via the aortic cannula or from impaired drainage of blood via the venous cannulae. However, techniques for continuous routine monitoring of regional perfusion in neonates or small infants undergoing cardiopulmonary bypass are extremely limited. Over recent years, transcranial near-infrared spectroscopy has become established as a useful technique for the non-invasive monitoring of cerebral oxygenation. Here we present a case in which simultaneous near-infrared spectroscopic monitoring of the oxygenation status in the brain and the right upper thigh revealed lower torso ischemia due to accidental cross-clamping of a hypoplastic descending aorta which would otherwise have been unnoticed. This shows that parallel near-infrared spectroscopy of the brain and the lower extremities may represent a novel non-invasive monitoring technique to ensure adequate cerebral and extracerebral perfusion during cardiopulmonary bypass.