Mitochondrial ATP Synthase Tetramer Disassembly following Blood-Based or del Nido Cardioplegia during Neonatal Cardiac Surgery.

Conservation of mitochondrial adenosine triphosphate (ATP) synthase proteins during ischemia is critical to preserve ATP supply and ventricular function. Following myocardial ischemia in adults, higher order ATP synthase tetramer proteins disassemble into simpler monomer units, reducing the efficiency of ATP production. However, it is unknown if myocardial ischemia following the use of cardioplegia results in tetramer disassembly in neonates, and whether it can be mitigated by cardioplegia if it does occur. We investigated myocardial ATP synthase tetramer disassembly in both a neonatal lamb cardiac surgery model and in neonatal children requiring cardiac surgery for the repair of congenital heart disease. Neonatal lambs (Ovis aries) were placed on cardiopulmonary bypass (CPB) and underwent cardioplegic arrest using a single dose of 30 mL/kg antegrade blood-based potassium cardioplegia (n = 4) or a single dose of 30 mL/kg antegrade del Nido cardioplegia (n = 6). Right ventricular biopsies were taken at baseline on CPB (n = 10) and after approximately 60 minutes of cardioplegic arrest before the cross clamp was released (n = 10). Human right ventricular biopsies (n = 3) were taken following 40.0 ± 23.1 minutes of ischemia after a single dose of antegrade blood-based cardioplegia. Protein complexes were separated on clear native gels and the tetramer to monomer ratio quantified. From the neonatal lamb model regardless of the cardioplegia strategy, the tetramer:monomer ratio decreased significantly during ischemia from baseline measurements (.6 ± .2 vs. .5 ± .1; p = .03). The del Nido solution better preserved the tetramer:monomer ratio when compared to the blood-based cardioplegia (Blood .4 ± .1 vs. del Nido .5 ± .1; p = .05). The tetramer:monomer ratio following the use of blood-based cardioplegia in humans aligned with the lamb data (tetramer:monomer .5 ± .2). These initial results suggest that despite cardioprotection, ischemia during neonatal cardiac surgery results in tetramer disassembly which may be limited when using the del Nido solution.

Cell Saver Blood Reinfusion Up to 24 Hours Post Collection in Pediatric Cardiac Surgical Patients Does Not Increase Incidence of Hospital-Acquired Infections or Mortality.

Cell saver blood reinfusion, a blood conservation technique recently available for pediatric use, is typically limited to 6 hours post processing to guard against bacterial contamination. We hypothesize that reinfusion of cell saver blood up to 24 hours post collection in children after cardiac surgery will not increase the incidence of hospital-acquired infections (HAI). The primary aim is to compare incidence of HAI between children receiving cell saver blood ≤6 hours vs. >6 to ≤24 hours from its collection. The secondary aim is to compare mortality and clinical outcomes. Retrospective chart review of children ≤18 years undergoing cardiac surgery with cardiopulmonary bypass (CPB) from 2013 to 2018 when cell saver collection and bedside temperature controlled storage became standard of care. Patients on extracorporeal membrane oxygenation (ECMO) within 48 hours postoperatively and those who did not receive cell saver were excluded. The primary outcome was HAI incidence postoperative days 0-6. Demographic data included diagnosis, surgical severity score, and clinical outcomes. 466 patients, 45% female. No significant between-group differences identified. There was no significant difference in HAI (control 8.5% vs. treatment 8.0%, p = .80) and death (control 7.9% vs. treatment 4.9%, p = .20). Noninferiority testing indicated the treatment group was not statistically inferior to the control group (p = .0028). Kaplan-Meier curve depicted similar status between-group rates of no infection or death; 92% treatment vs. 91% control. Total volume allogeneic red blood cell transfusion (allogeneic blood transfusion [ABT]) up to 24 hours postoperatively was significantly less in the treatment group, p < .0001. Incidence of HAI or mortality was not increased in patients receiving cell saver blood reinfusion >6 to ≤24 hours post collection. Treatment subjects received significantly less volume of ABT. Considering the risks of ABT, these findings support cell saver blood reinfusion up to 24 hours post collection.

In Vitro and In Vivo Comparison of Hemoglobin and Electrolytes Following the Collection of Cell Saver Blood Washed with Either Normal Saline or Plasma-Lyte A.

Cell saver blood is typically washed with normal saline (NS); however, recent studies have reported decreased red blood cell hemolysis and increased platelet function when a more physiologic washing solution, such as Plasma-Lyte A (PL-A) is used. We evaluated the in vitro and in vivo effects of NS compared to PL-A as washing solutions for cell saver blood in pediatric cardiac surgery. Cell saver blood was re-infused for up to 24 hours post-collection. Laboratory and clinical data were collected from infants receiving cell saver washed with either NS (n = 20) or PL-A (n = 21). Compositions of the cell saver blood were compared between groups at 5 in vitro time points and in vivo patient blood at 24 hours post-bypass. Although there were differences in in vitro laboratory values between groups; 24 hours post-bypass, in vivo results were similar. Our data supports 24-hour reinfusion of cell saver washed with either NS versus PL-A in pediatric cardiac surgery patients, and provides data on the differences in cell saver composition to guide future studies.

Neurodevelopmental Delay After the Neonatal Repair of Coarctation and Arch Obstruction.

BACKGROUND: Although single ventricle physiology and cyanosis are known risk factors for neurodevelopmental delay (NDD), the impacts of isolated coarctation (Iso CoA) repair or arch reconstruction (AR) are less understood. METHODS: The Vineland Adaptive Behavior Scales, third edition, prospectively evaluated children without a genetic syndrome. An overall composite score, normalized to age and sex, was generated from individual domain scores. NDD was defined as a composite or domain score at least 1 SD less than the established mean. Iso CoA was repaired using a left thoracotomy, whereas AR was performed using a sternotomy and cardiopulmonary bypass. Children with a structurally normal heart and without previous surgery were used as control patients. RESULTS: Of 60 children, 50 required neonatal repair (12 for Iso CoA, 38 for AR), and 10 were control patients. From the entire cohort of children who required neonatal coarctation repair (Iso CoA + AR) composite (93.9 ± 15.9 vs 105.0 ± 7.4; P = .004) and all domain scores were significantly lower than control patients. NDD was present in 25 of 50 children after repair and in 0 of 10 control patients (P = .003). Similarly, the prevalence of NDD was significantly greater after Iso CoA repair (58.3% vs 0%; P = .005) and AR (47.3% vs 0%; P = .007) than in the control population, but no significant difference was found between the Iso CoA and AR groups (P = .74). CONCLUSIONS: In this small cohort, half of the neonates who required either Iso CoA repair or AR exhibit NDD at an intermediate-term follow-up.

Neurodevelopmental outcomes after neonatal cardiac surgery: Role of cortical isoelectric activity.

OBJECTIVES: Neonates with congenital heart disease are at risk for impaired neurodevelopment after cardiac surgery. We hypothesized that intraoperative EEG activity may provide insight into future neurodevelopmental outcomes. METHODS: Neonates requiring surgery had continuous intraoperative EEG and hemodynamic monitoring. The level of EEG suppression was classified as either: slow and continuous; moderate burst suppression; severe burst suppression; or isoelectric (no brain activity for >3 minutes). Follow-up neurodevelopmental outcomes were assessed using the Vineland Adaptive Behavior Scale II (Vineland-II). RESULTS: Twenty-one neonates requiring cardiac surgery developed a slow and continuous EEG pattern after general anesthesia. Ten neonates (48%) maintained continuous brain electrical activity with moderate burst suppression as the maximum level of EEG suppression. Eleven neonates (52%) developed severe burst suppression that progressed into an isoelectric state during the deep hypothermic period required for circulatory arrest. However, the duration of this state was significantly longer than circulatory arrest times (111.1 ± 50 vs 22.3 ± 17 minutes; P < .001). At a mean follow-up at 5.6 ± 1.0 years, compared with neonates with continuous brain electrical activity, neonates who developed an isoelectric state had lower Vineland-II scores in communication. There was an inverse relationship between composite Vineland-II scores and duration of isoelectric activity (R = -0.75, P = .01). Of neonates who experienced an isoelectric state, durations of >90 minutes were associated with the lowest Vineland-II scores (125.0 ± 2.6 vs 81.1 ± 12.7; P < .01). CONCLUSIONS: The duration of cortical isoelectric states seems related to neurodevelopmental outcomes. Strategies using continuous EEG monitoring to minimize isoelectric states may be useful during complex congenital heart surgery.

The effect of repeat sternotomy during right ventricular outflow tract reconstruction.

OBJECTIVE: Right ventricular outflow tract (RVOT) reconstruction necessitates frequent reoperation. To understand the early outcomes, we analyzed our results to provide the intra- and postoperative morbidity and mortality. We hypothesized that multiple previous sternotomies do not influence the morbidity, mortality, or survival. DESIGN: We performed a retrospective review of patients who underwent reoperative RVOT reconstruction at the University of Rochester Medical Center and SUNY Upstate Medical Center from January 1, 2000 to December 31, 2009. Patients were divided into three groups based upon the number of previous sternotomies: Group 1 with one, Group 2 with two, and Group 3 with three or more previous sternotomies. RESULTS: 220 patients had reoperative RVOT reconstruction, 103 in Group 1, 71 in Group 2, and 46 in Group 3. There was no difference in the percentage of inadvertent cardiotomy between groups (Group 1: 2%, Group 2: 1%, Group 3: 2%; P =.9) The number of previous sternotomies had no effect upon infection, arrhythmia, or the percentage of patients who received a red blood cell transfusion (Group 1: 56%, Group 2: 49% Group 3: 43%; P =.3). Perioperative mortality for the entire group was 3/220 (1.4%), with no difference between groups. At a mean follow-up of 39 months, there was a survival of 98% for Groups 1 and 3 and 97% for Group 2 (P =.7). CONCLUSION: Reoperative RVOT reconstruction can safely be performed with limited morbidity and mortality. The number of previous sternotomies does not influence the rate of cardiotomy, red blood cell transfusion, or early outcome.

An inexpensive cardiac bypass cannulation simulator: facing challenges of modern training.

The importance of surgical simulation has grown in the quickly changing climate of modern surgical training. As the expectation of basic skills acquisition has shifted to forums outside the operating room, residency programs have struggled to provide realistic teaching simulations for their trainees. We have developed and tested a realistic and low-cost porcine cannulation model. This model provided a platform for both technical and cognitive skills acquisition at the first session of the cardiothoracic or "CT Surgery Boot Camp" during the summer of 2008.