Pilot Assessment of Platelet Thrombus Area and Contractile Force in Pediatric Congenital Heart Surgery Patients Using a Microfluidic Device.

OBJECTIVES: This work was designed to evaluate maximum platelet contractile force and thrombus area before and after cardiopulmonary bypass (CPB) in pediatric patients having congenital heart disease (CHD) surgery using a microfluidic device. DESIGN: A prospective cohort study was designed. SETTING: The work took place at an academic medical center. PARTICIPANTS: Twenty pediatric CHD patients ≤8 years of age with expected CPB time >30 minutes were enrolled. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Blood was collected at baseline and post-CPB. Maximum platelet contractile force and thrombus area were evaluated in vitro using a microfluidic device (ATLAS PST). Post-CPB samples were supplemented with recombinant von Willebrand factor (rVWF) to explore the impact on contractile force and thrombus area. At baseline, the maximum thrombus area was 0.06 (0.05, 0.07), and the maximum force was 123.3 nN (68.4, 299.5). Linear mixed-effects regression models showed that the maximum thrombus area was larger post-CPB and post-CPB + rVWF compared with pre-CPB (estimated coefficient [Est] = 0.04, p = 0.002; Est = 0.09, p < 0.001, respectively). The maximum thrombus area was also larger post-CPB + rVWF compared with post-CPB (Est = 0.04, p = 0.001). Force was higher post-CPB + rVWF compared with pre-CPB (Est = 173.32, p = 0.044). CONCLUSIONS: In pediatric CHD patients, microfluidic testing demonstrated that platelet thrombus area increased slightly after CPB, while platelet contractile force did not change. In vitro addition of rVWF further increased thrombus area, suggesting augmentation of primary hemostasis. Microfluidic assessment of platelet contractile force and thrombus area in pediatric CHD patients appears feasible and can demonstrate changes after CPB. Further studies are needed to determine its accuracy, clinical utility, and normal values for pediatric patients.

Report of the 2022 Society of Thoracic Surgeons Congenital Heart Surgery Practice Survey.

BACKGROUND: The Society of Thoracic Surgeons Workforce on Congenital Surgery performed a practice survey to analyze contemporary data. METHODS: An electronic survey was sent to congenital heart surgeons in North America. Details on demographics, training paradigm, clinical practice, and work satisfaction were queried, tabulated, and analyzed. RESULTS: Of 312 unique contacts, 201 (64.4%) responded. Of these, 178 (89%) were practicing. The median age was 52 years (interquartile range, 43, 59 years), and 157 (88%) were male. The number of female respondents increased from 12 (7%) in 2015 to 18 (11%) at present. Practice composition was predominantly mixed pediatric and adult (141; 79%), although 15 (8%) surgeons practiced exclusively pediatric surgery. Most surgeons (154; 87%) reported performing the Society of Thoracic Surgeons-European Association for Cardio-Thoracic Surgery category 4 and 5 procedures. One-fourth (42; 24%) reported performing fewer than 50 pediatric cases per year, and 18 (10%) stated that their primary role was as a surgical assistant. Individual surgeon case volume was most commonly 100 to 149 total cases (29%). Although one-half (91; 51%) reported their volume as being "just right," 74 (42%) reported that their case volume was "too small." Seventy-six (43%) reported too many surgeons in their region. Of the 201 practicing surgeons, 30 (14.9%) plan retirement in the next 5 years. Most described career satisfaction, with 102 (57%) being very satisfied and 48 (27%) somewhat satisfied. CONCLUSIONS: Although most congenital heart surgeons in North America are satisfied with their careers, more than 40% believe that their caseload is inadequate and that there are too many surgeons in their region. Further analysis is warranted regarding career dissatisfaction and diversity.

Development and Validation of a Seizure Prediction Model in Neonates After Cardiac Surgery.

BACKGROUND: Electroencephalographic seizures (ESs) after neonatal cardiac surgery are often subclinical and have been associated with poor outcomes. An accurate ES prediction model could allow targeted continuous electroencephalographic monitoring (CEEG) for high-risk neonates. METHODS: ES prediction models were developed and validated in a multicenter prospective cohort where all postoperative neonates who underwent cardiopulmonary bypass (CPB) also underwent CEEG. RESULTS: ESs occurred in 7.4% of neonates (78 of 1053). Model predictors included gestational age, head circumference, single-ventricle defect, deep hypothermic circulatory arrest duration, cardiac arrest, nitric oxide, extracorporeal membrane oxygenation, and delayed sternal closure. The model performed well in the derivation cohort (c-statistic, 0.77; Hosmer-Lemeshow, P = .56), with a net benefit (NB) over monitoring all and none over a threshold probability of 2% in decision curve analysis (DCA). The model had good calibration in the validation cohort (Hosmer-Lemeshow, P = .60); however, discrimination was poor (c-statistic, 0.61), and in DCA there was no NB of the prediction model between the threshold probabilities of 8% and 18%. By using a cut point that emphasized negative predictive value in the derivation cohort, 32% (236 of 737) of neonates would not undergo CEEG, including 3.5% (2 of 58) of neonates with ESs (negative predictive value, 99%; sensitivity, 97%). CONCLUSIONS: In this large prospective cohort, a prediction model of ESs in neonates after CPB had good performance in the derivation cohort, with an NB in DCA. However, performance in the validation cohort was weak, with poor discrimination, poor calibration, and no NB in DCA. These findings support CEEG of all neonates after CPB.

Cardiopulmonary Bypass and Infant Vaccination Titers.

BACKGROUND: Infants with congenital heart disease remain vulnerable to potentially preventable pathogens. Although immunization can significantly reduce this risk, it is unknown how immunization status can be affected by cardiac surgery with cardiopulmonary bypass (CPB). The objective was to evaluate the effect of CPB on infant vaccination status after cardiac surgery. METHODS: We conducted a prospective observational study of patients between 2 and 14 months of age who had received at least their first round of infant vaccinations and who required cardiac surgery with CPB. Antibody titers were measured before CPB and again the following morning. Demographic and surgical variables were assessed via regression methods for their effects on the change in titers. RESULTS: Among the 98 patients followed, there was no demonstrated difference between the pre- and postoperative values in regard to diphtheria, tetanus, polio 1, polio 3, or Haemophilus influenzae titers. Bordetella (1.03 vs 0.84, P < .001), and hepatitis B (log 2.10 vs 1.89, P = .001) titers did reduce after CPB but did not fall below the immunized threshold. Changes in antibody titers were not associated with time between immunization and surgery, age or weight at surgery, blood products administered, number of previous doses, time on CPB, or heterotaxy diagnosis for most of the vaccines. CONCLUSIONS: Infant vaccine antibody titers were minimally affected by CPB and not associated with any easily modifiable surgical variables. Although antibody titers are only 1 marker of immunity, deviation from the recommended vaccination schedule may be unnecessary for children requiring congenital heart surgery.

Prevalence of Culture-Negative Fever in Infants With Down Syndrome Undergoing Cardiac Surgery.

BACKGROUND: Children with Down syndrome (DS) often have congenital heart disease that requires surgical repair in the first year. Anecdotally, we have noted that patients with DS seem to have a higher rate of culture-negative postoperative fever. The objective was to evaluate the prevalence of postoperative fever and recovery among patients with DS undergoing cardiac surgery. METHODS: We conducted a retrospective, case-control study of all patients at our institution less than one year of age with DS undergoing surgical repair of an atrioventricular septal defect or ventricular septal defect between 2010 and 2016. The control group was patients with no chromosomal anomalies who were age and surgery matched to the DS group. Temperatures were recorded for the first 72 hours postoperatively, with duration and degree of fever being assessed using the area under the curve. RESULTS: Patients with DS (n = 34) had a significantly higher prevalence of fever than the control group (59% vs 24%, P = .003), longer ventilator time, and longer length of stay. Among the DS group, those who developed fever tended to be older at the time of surgery (146 ± 63 vs 103 ± 45 days, P = .04). The DS group with fever had similar cardiopulmonary bypass times, intensive care unit and total lengths of stay, ventilator days, and hospital costs compared to patients with DS without fever. CONCLUSIONS: Patients with DS have a higher incidence of culture-negative fever within the first 72 hours. The presence of fever in these patients, however, does not affect their overall postoperative course.

Malrotation is not associated with adverse outcomes after cardiac surgery in patients with heterotaxy syndrome.

BACKGROUND: Patients with heterotaxy syndrome (HS) often have asymptomatic malrotation. There is a lack of consensus regarding the management of these patients, particularly in patients with complex congenital heart disease (CHD). We sought to describe the prevalence of malrotation and incidence of volvulus in a population of patients with complex CHD and to identify the impact of malrotation on morbidity and mortality following cardiac surgery. METHODS: We performed a retrospective review of all patients with HS and complex CHD who required cardiac surgery in the first year of life at a single center between October 1995 and September 2015. Malrotation was diagnosed by abdominal imaging or by direct inspection during abdominal surgery. Demographic data was collected along with details of hospitalization following cardiac and GI surgeries. Descriptive analysis along with appropriate hypothesis testing was conducted to evaluate the results. RESULTS: We identified 49 patients with HS, 42 with single ventricle anatomy and 7 with biventricular anatomy. Of the 49 patients, 29 (59%) were diagnosed with malrotation, 6 (12%) had normal intestinal rotation, and 14 (29%) had no evaluation of intestinal rotation. The prevalence of malrotation in the population who underwent abdominal imaging was 29 out of 35 (83%). There was no difference in survival following cardiac surgery between patients with malrotation and those with unknown or normal intestinal anatomy. Comparing patients with malrotation and patients with normal or unknown intestinal rotation, there was also no difference in surrogate markers of morbidity. Of the 29 patients with known malrotation, only 2 patients (7%) underwent therapeutic Ladd procedures and 19 (65%) underwent prophylactic Ladd procedures. CONCLUSIONS: We conclude that the outcomes following cardiac surgery for patients with HS are not impacted by the presence of malrotation. Furthermore, we also found that the incidence of volvulus in the studied group is low. Given these findings, and the understanding that patients with HS and significant CHD are frequently tenuous and high risk surgical candidates, we do not believe performing prophylactic Ladd procedures is warranted. LEVEL OF EVIDENCE: III.

Use of Nicardipine After Cardiac Operations Is Safe in Children Regardless of Age.

BACKGROUND: Control of postoperative hypertension is central to the care of infants and children after cardiac operations. Continuous pharmacologic delivery affords the advantage of rapid onset and ease of titration. Although well established in older children and adults, calcium channel blockers are routinely avoided in children aged younger than 1 year secondary to concerns of safety and efficacy in the setting of sarcoplasmic reticulum development. Thus, the purpose of this study was to review a single-institution experience with nicardipine, a selective calcium channel blocker, in pediatric patients after cardiac operations. METHODS: Children undergoing cardiac operations at the University of Virginia from 2010 to 2015 were retrospectively reviewed after selection based on receipt of nicardipine for blood pressure management in the postoperative period. Demographic, operative, laboratory, and postoperative data were collected for adverse effect analysis and outcomes comparisons between infants aged younger than 6 months (group 1) and older than 6 months (group 2). RESULTS: During the study period, 68 children (group 1: n = 33 [48%]; group 2: n = 35 [52%]) received nicardipine after cardiac operations (0.5 to 1 µg · kg-1 · min-1). Nicardipine was initiated at a mean of 6.6 ± 13.1 hours postoperatively in group 1 and 5.4 ± 7.8 hours in group 2. Nine patients (13%) demonstrated clinically significant hypotension necessitating dosing titration with no statistically significant differences between groups. No major adverse events occurred following nicardipine administration. CONCLUSIONS: Nicardipine is well tolerated after cardiac operations in children irrespective of age or underlying pathology. Thus, nicardipine should be considered as safe and effective in children of all ages for control of hypertension after cardiac operations.

Decreased blood product usage during extracorporeal life support with reduced circuit volumes.

BACKGROUND: Activation and consumption of platelets (PLT) and clotting factors along with hemolysis occurs when blood contacts the extracorporeal life support (ECLS) circuit and its components. STUDY DESIGN AND METHODS: The objective was to examine the effects of reducing ECLS circuit volume by decreasing tubing length and changing components on blood product usage in neonatal and pediatric patients. Blood product administration was analyzed in 40 consecutive patients who required ECLS for respiratory or cardiac failure before (PRE) and after (POST) changes in circuit design and components. RESULTS: The total circuit volume was reduced from 500 mL (PRE) to 275 mL (POST). In the POST group, total blood product volume usage was 58% lower compared to the PRE group (81 mL/kg/day vs. 191 mL/kg/day, p = 0.003), 65% lower for fresh-frozen plasma (FFP; 15 mL/kg/day vs. 43 mL/kg/day, p = 0.001), and PLT volumes trended lower. In the subgroup of infants with respiratory or cardiac failure, there was a 55% reduction of a total blood product replacement (61 mL/kg/day vs. 136 mL/kg/day, p = 0.008), red blood cell (RBC) use was 61% lower (28 mL/kg/day vs. 71 mL/kg/day, p < 0.049), and there was a 73% reduction in FFP use (11 mL/kg/day vs. 41 mL/kg/day, p < 0.001). In the subgroup of postoperative infants, there was a 25% decrease in RBC use (86 mL/kg/day vs. 115 mL/kg/day, p = 0.03). CONCLUSION: Decreasing the ECLS circuit volume by reducing the tubing length and changing the components was associated with a significant reduction in blood product usage.

Excision of an intrapericardial immature teratoma in a 26-week premature neonate.

We present a case of a 26 week premature newborn with an immature intrapericardial teratoma. The patient was transferred from an outside hospital for management of a large mediastinal mass causing respiratory insufficiency. The newborn was supported with the help of a large interdisciplinary team until day of life 22 when he underwent surgical excision. On follow up the infant is doing very well and is one of the youngest survivors to date.

Face-to-face handoff: improving transfer to the pediatric intensive care unit after cardiac surgery.

The goal was to develop and implement a comprehensive, primarily face-to-face handoff process that begins in the operating room and concludes at the bedside in the intensive care unit (ICU) for pediatric patients undergoing congenital heart surgery. Involving all stakeholders in the planning phase, the framework of the handoff system encompassed a combination of a formalized handoff tool, focused process steps that occurred prior to patient arrival in the ICU, and an emphasis on face-to-face communication at the conclusion of the handoff. The final process was evaluated by the use of observer checklists to examine quality metrics and timing for all patients admitted to the ICU following cardiac surgery. The process was found to improve how various providers view the efficiency of handoff, the ease of asking questions at each step, and the overall capability to improve patient care regardless of overall surgical complexity.

Coarctation of the aorta - the current state of surgical and transcatheter therapies.

Aortic coarctation represents a distinct anatomic obstruction as blood moves from the ascending to the descending aorta and can present in a range of ages from infancy to adulthood. While it is often an isolated and discrete narrowing, it can also be seen in the more extreme scenario of severe arch hypoplasia as seen in the hypoplastic left heart syndrome or in conjunction with numerous other congenital heart defects. Since the first description of an anatomic surgical repair over sixty years ago, an evolution of both surgical and transcatheter therapies has occurred allowing clinicians to manage and treat this disease with excellent results and low morbidity and mortality. This review focuses on the current state of both transcatheter and surgical therapies, paying special attention to recent data on long-term follow-up of both approaches. Further, current thoughts will be explored about future therapeutic options that attempt to improve upon historical long-term outcomes.

Right-ventricular global longitudinal strain may predict neo-aortic arch obstruction after Norwood/Sano procedure in children with hypoplastic left heart syndrome.

Neo-aortic arch obstruction (NAAO) is a common complication following the Norwood/Sano procedure (NP) for hypoplastic left heart syndrome (HLHS) and is associated with increased morbidity and mortality. However, there is currently no objective method for predicting which patients will develop NAAO. This study was designed to test the hypothesis that hemodynamic changes from development of NAAO after NP in patients with HLHS will lead to changes in myocardial dynamics that could be detected before clinical symptoms develop with strain analysis using velocity vector imaging. Patients with HLHS who had at least one cardiac catheterization after NP were identified retrospectively. Strain analysis was performed on all echocardiograms preceding the first catheterization and any subsequent catheterization performed for intervention on NAAO. Twelve patients developed NAAO and 30 patients never developed NAAO. Right ventricular strain was worse in the group that developed NAAO (-6.2 vs. -8.6 %, p = 0.040) at a median of 59 days prior to diagnosis of NAAO. Those patients that developed NAAO following NP were significantly younger at the time of first catheterization than those that did not develop NAAO (92 ± 50 vs. 140 ± 36 days, p = 0.001). This study demonstrates that right ventricular GLS is abnormal in HLHS patients following NP and worsening right ventricular strain may be predictive of the future development of NAAO.

Head and neck vessel size by angiography predicts neo-aortic arch obstruction after Norwood/Sano operation for hypoplastic left heart syndrome.

OBJECTIVES: To identify and predict neo-aortic arch obstruction (NAAO) in children after Norwood/Sano operation (NO) for hypoplastic left heart syndrome (HLHS). BACKGROUND: NAAO is associated with morbidity and mortality after NO for HLHS and no objective measure has predicted the initial occurrence of NAAO. Computational flow models of aortic coarctation demonstrate increased wall shear stress (WSS) in vessels proximal to the coarctation segment, which we believe also occurs with NAAO. These vessels respond by increasing their luminal diameter to maintain normal WSS. We hypothesized that the relative increase in diameters of head and neck vessels to the isthmus, as measured by angiography, would identify hemodynamically significant NAAO and predict future NAAO. METHODS: Retrospective review of patients with HLHS and at least one catheterization with aortic angiography after NO. Diameters of head and neck vessels were totaled and divided by the isthmus diameter to give a head and neck index (HNI), which was compared to coarctation index (CI) for identifying and predicting future NAAO. RESULTS: Forty-four patients were identified, 17 with and 27 without NAAO. Receiver operator characteristic analysis using a value for CI ≤0.5 showed a sensitivity of 47% and specificity of 89%. For HNI, a value >2.65 gave a sensitivity of 77% and specificity of 93%. Three patients who developed NAAO after their initial catheterization had CI >0.5, but abnormally high HNI >2.65. CONCLUSIONS: HNI is a more robust indicator of hemodynamically significant NAAO than CI and may predict its future occurrence after NO for HLHS.

A viable therapeutic option: mechanical circulatory support of the failing Fontan physiology.

A blood pump specifically designed to augment flow from the great veins through the lungs would ameliorate the poor physiology of the failing univentricular circulation and result in a paradigm shift in the treatment strategy for Fontan patients. This study is the first to examine mechanical cavopulmonary assistance with a blood pump in the inferior vena cava (IVC) and hepatic blood flow. Five numerical models of mechanical cavopulmonary assistance were investigated using a three-dimensional, reconstructed, patient-specific Fontan circulation from magnetic resonance imaging data. Pressure flow characteristics of the axial blood pump, energy augmentation calculations for the cavopulmonary circulation with and without pump support, and hemolysis estimations were determined. In all of the pump-supported scenarios, a pressure increase of 7-9.5 mm Hg was achieved. The fluid power of the cavopulmonary circulation was also positive over the range of flow rates. No retrograde flow from the IVC into the hepatic circulation was evident during support cases. Vessel suction risk, however, was found for greater operating rotational speeds. Fluid shear stresses and hemolysis predictions remained at acceptable levels with normalized index of hemolysis estimations at 0.0001 g/100 L. The findings of this study support the continued design and development of this blood pump technology for Fontan patients with progressive cardiovascular insufficiency. Validation of these flow and performance predictions will be completed in the next round of experimental testing with blood bag evaluation.

Short and long-term outcomes for bidirectional glenn procedure performed with and without cardiopulmonary bypass.

BACKGROUND: The bidirectional Glenn (BDG) procedure is most commonly used as staged palliation for complex cyanotic congenital heart defects. The benefits of a BDG procedure without the use of cardiopulmonary bypass (CPB) remain mixed within reported series. The purpose of this study was to compare short- and long-term outcomes for performance of a BDG procedure with and without the use of CPB. METHODS: From 2001 to 2010, 106 patients underwent a BDG procedure. Patients were stratified into CPB (n = 72; age = 202 days) and non-CPB (n = 34; age = 182 days) groups. Primary outcomes included operative mortality and postoperative complications as well as differences in long-term Kaplan-Meier survival. RESULTS: Median follow-up was 30 months. Preoperative patient characteristics were similar among patients despite the use of CPB. The most frequent indications for a BDG procedure were hypoplastic left heart syndrome (HLHS) (35.8%) and tricuspid atresia (TA) (17.9%). Median perfusion time was 73 minutes for CPB patients. Overall mortality was 0.9% and no deaths occurred among non-CPB patients (0.0% versus 1.4%; p > 0.99). Similarly, no significant differences existed between non-CPB patients and CPB patients with respect to overall complication rates (11.8% versus 18.1%; p = 0.57) or postoperative length of stay (7.0 [5.0-12.0] versus 7.0 [5.0-11.0] days; p = 0.38). Furthermore, 1-, 3-, and 5-year survival was high and similar between groups. CONCLUSIONS: The BDG procedure can be performed with no significant differences in operative mortality, morbidity, or use of resources, with or without CPB support. Long-term survival after the BDG procedure is high with both strategies. Performance of an off-pump BDG procedure should be considered a safe alternative to the conventional use of CPB for appropriately selected patients.