Neurological Injury After Neonatal Cardiac Surgery

Standardization of the Norwood Procedure Improves Outcomes in a Medium-Sized Volume Center

The Norwood operation has become common practice to palliate patients with hypoplastic left heart structures. Surgical technique and postoperative care have improved; yet, there remains significant attrition prior to stage II palliation. The objective of this study is to report outcomes before and after standardizing our approach to the Norwood operation. Patients who underwent the Norwood operation at Children's of Alabama were identified, those who underwent hybrid palliation operations were excluded. Pre- (2015-2020) and post- (2020-January 2023) standardization groups were compared and outcomes analyzed. Ninety-one patients were included (pre-standardization 44 (48.3%) and 47 (51.7%) post-standardization). There were no differences in baseline and intraoperative characteristics at Norwood between the pre- and post-standardization groups. Compared with pre-standardization, post-standardization was associated with decreased time to extubation (OR 0.87, 95%CI 0.79-0.96), inotrope duration (OR 0.92, 95%CI 0.86-0.98) and hospital length of stay (OR 0.98, 95%CI 0.96-0.99). There was a trend toward decreased cardiac arrest, reintervention rates, and interstage mortality for the post-standardization group. A standardized approach to complex neonatal cardiac operations such as the Norwood procedure may improve morbidity and decrease hospital resource utilization. We recommend establishing protocols at an institutional level to optimize outcomes in such high-risk patient populations.

Cerebral blood flow dynamics during cardiac surgery in infants

BACKGROUND

In this pilot study, we investigated continuous cerebral blood flow velocity measurements to explore cerebrovascular hemodynamics in infants with congenital heart disease undergoing cardiac surgery.

METHODS

A non-invasive transfontanellar cerebral Doppler monitor (NeoDoppler) was used to monitor 15 infants (aged eight days to nine months) during cardiac surgery with cardiopulmonary bypass. Numerical and visual analyses were conducted to assess trends and events in Doppler measurements together with standard monitoring equipment. The mean flow index, calculated as the moving Pearson correlation between mean arterial pressure and time averaged velocity, was utilized to evaluate dynamic autoregulation. Two levels of impaired autoregulation were defined (Mean flow index >0.3/0.45), and percentage of time above these limits were calculated.

RESULTS

High quality recordings were achieved during 90.6% of the monitoring period. There was a significant reduction in time averaged velocity in all periods of cardiopulmonary bypass. All patients showed a high percentage of time with impaired dynamic autoregulation, with Mean flow index >0.3 and 0.45: 73.71% ± 9.06% and 65.16% ± 11.27% respectively. Additionally, the system promptly detected hemodynamic events.

CONCLUSION

Continuous transfontanellar cerebral Doppler monitoring could become an additional tool in enhancing cerebral monitoring in infants during cardiac surgery.

IMPACT

This pilot study demonstrates the feasibility of continuous transfontanellar Doppler monitoring of cerebral blood flow velocities during cardiac surgery in infants. It also demonstrates a high proportion of time with impaired cerebral autoregulation during cardiac surgery based on the Mean flow index. Continuous transfontanellar Doppler could become a useful tool to improve cerebral monitoring and provide new pathophysiological insight.

Neurological injury in pediatric heart disease: A review of developmental and acquired risk factors and management considerations

Medical and surgical advancements have improved survival in children with acquired and congenital heart disease (CHD), but the burden of neurological morbidity is high. Brain disorders associated with CHD include white matter injury, stroke, seizure, and neurodevelopmental delays. While genetics and disease-specific factors play a substantial role in early brain injury, therapeutic management of the heart disease intensifies the risk. There is a growing interest in understanding how to reduce brain injury and improve neurodevelopmental outcomes in cardiac diseases. Pediatric neurologists serve a vital role in care teams managing these complex patients, providing interpretation of neuromonitoring and imaging, managing neurologic emergencies, assisting with neuro prognostication, and identifying future research aims.

Using interleukin-18, Eotaxin-1, and Eotaxin-3 to identify brain injury in neonates with congenital heart disease

OBJECTIVES

Serum biomarkers for brain injury in neonates with congenital heart disease (CHD) provide a bedside tool for early identification and intervention. In this preliminary study, we aim to evaluate IL-18, Eotaxin-1 and Eotaxin-3 as biomarkers for the detection of brain injury in neonates with CHD.

METHODS

We prospectively enrolled seven neonates diagnosed in-utero with CHD and obtained serum samples at birth, before and after surgery. Samples were analyzed using a human cytokine/chemokine multiplex assay. Brain injury was diagnosed on brain MRI before surgery.

RESULTS

Samples from seven neonates at four time points before surgery and three time points after surgery were analyzed. A significant difference was found in neonates with brain injury compared to CHD neonates without. Elevations in interleukin (IL)-18 pre- and post-operative (p = 0.007), IL-18 pre-operative (p = 0.046), Eotaxin-1 pre-operative (p = 0.011), and Eotaxin-3 pre- and post-operative (p = 0.026) were found in CHD neonates with brain injury.

CONCLUSION

This is the first published report on the use IL-18, Eotaxin-1, and Eotaxin-3 in the detection of brain injury for neonates with CHD. These biomarkers may provide an actionable target for neuroprotection through immunomodulation. Larger cohorts are needed to determine the significance and clinical utility of these biomarkers.

Incidence of postoperative seizures in neonates following cardiac surgery with regional cerebral perfusion and deep hypothermic circulatory arrest

Objectives

Historically, our center has primarily used deep hypothermic circulatory arrest, but in recent years some surgeons have selectively used regional cerebral perfusion as an alternative. We aimed to compare the incidence of postoperative electroencephalographic seizure incidence in neonates undergoing surgery with regional cerebral perfusion and deep hypothermic circulatory arrest.

Methods

A retrospective analysis was performed in neonates who underwent surgery between 2012 and 2022 with either deep hypothermic circulatory arrest or regional cerebral perfusion with routine postoperative continuous electroencephalography monitoring for 48 hours. Propensity matching was performed to compare postoperative seizure risk between the 2 groups.

Results

Among 1136 neonates undergoing cardiac surgery with cardiopulmonary bypass, regional cerebral perfusion was performed in 99 (8.7%) and deep hypothermic circulatory arrest in 604 (53%). The median duration of regional cerebral perfusion was 49 minutes (interquartile range, 38-68) and deep hypothermic circulatory arrest was 41 minutes (interquartile range, 31-49). The regional cerebral perfusion group had significantly longer total support, cardiopulmonary bypass, and aortic crossclamp times. Overall seizure incidence was 11% (N = 76) and 13% (N = 35) in the most recent era (2019-2022). The unadjusted seizure incidence was similar in neonates undergoing regional cerebral perfusion (N = 12, 12%) and deep hypothermic circulatory arrest (N = 64, 11%). After propensity matching, the seizure incidence was similar in neonates undergoing regional cerebral perfusion (N = 12, 12%) and deep hypothermic circulatory arrest (N = 37, 12%) (odds ratio, 0.97; 95% CI, 0.55-1.71; P = .92).

Conclusions

In this contemporary single-center experience, the incorporation of regional cerebral perfusion did not result in a change in seizure incidence in comparison with deep hypothermic circulatory arrest. However, unmeasured confounders may have impacted these findings. Further studies are needed to determine the impact, if any, of regional cerebral perfusion on postoperative seizure incidence.

Perioperative Brain Injury in Children with Aortic Arch Anomalies: A Retrospective Study of Risk Factors and Outcomes

Complex pediatric cardiac disease is associated with brain impairment and neurodevelopmental disorders, particularly in patients requiring cardiac surgery for aortic arch anomalies. This study examines the incidence, risk factors, and outcomes of perioperative brain injury in children undergoing aortic arch repair who had aortic arch anomalies. A total of 145 children with aortic arch anomalies in our center undergoing aortic arch repair between January 2014 and December 2022 were enrolled. There were 129 (89.0%) with coarctation of the aorta (COA) and 16 (9.7%) with interrupted aortic arch (IAA). Risk factor analysis of brain injuries was done using perioperative imaging and included symptoms of hemorrhagic stroke, arterial ischemic stroke, white matter injury, cerebral sinus venous thrombosis, and other pathologies. Preoperatively, 50/145 (34.5%) patients had brain injuries. Multivariate analysis showed that an increased risk of hemorrhagic stroke was associated with newborns (odds ratio [OR], 2.09 [95% CI 0.08-3.50]), isolated COA (OR, 3.69 [95% CI 1.23-7.07]), mechanical ventilation (MV) ([OR, 2.56 [95% CI 1.25-4.03]), and sepsis (OR, 1.73 [95% CI 0.46-3.22]). Newborns ([OR, 1.91 [95% Cl 0.58-3.29]) and weight-for-age z score ([OR, -0.45 [95% CI -0.88 to -0.1]) were associated with an increased risk of white matter injury. New postoperative brain injuries were present in 12.9% of the patients (16/124). Deep hypothermic circulatory arrest (DHCA) was associated with new postoperative brain injuries compared with deep hypothermic low-flow (DHLF) plus antegrade cerebral perfusion (ACP) (([OR, 2.67 [95% CI, 0.58-5.75])). Isolated COA was almost associated with new postoperative brain injuries (OR, 1.13 [95% CI, -0.04 to 2.32]). Children diagnosed with isolated COA appeared to have a higher risk of perioperative brain injury, but the underlying mechanisms are still unclear. We focused on the intrinsic mechanism by which changes in hemodynamics caused by COA result in perioperative brain injury. Further research will be needed to optimize the personalized treatment and cerebral perfusion techniques for complex pediatric cardiac surgery.

The use of novel diffuse optical spectroscopies for improved neuromonitoring during neonatal cardiac surgery requiring antegrade cerebral perfusion

Background

Surgical procedures involving the aortic arch present unique challenges to maintaining cerebral perfusion, and optimal neuroprotective strategies to prevent neurological injury during such high-risk procedures are not completely understood. The use of antegrade cerebral perfusion (ACP) has gained favor as a neuroprotective strategy over deep hypothermic circulatory arrest (DHCA) due to the ability to selectively perfuse the brain. Despite this theoretical advantage over DHCA, there has not been conclusive evidence that ACP is superior to DHCA. One potential reason for this is the incomplete understanding of ideal ACP flow rates to prevent both ischemia from underflowing and hyperemia and cerebral edema from overflowing. Critically, there are no continuous, noninvasive measurements of cerebral blood flow (CBF) and cerebral oxygenation (StO₂) to guide ACP flow rates and help develop standard clinical practices. The purpose of this study is to demonstrate the feasibility of using noninvasive, diffuse optical spectroscopy measurements of CBF and cerebral oxygenation during the conduct of ACP in human neonates undergoing the Norwood procedure.

Methods

Four neonates prenatally diagnosed with hypoplastic left heart syndrome (HLHS) or a similar variant underwent the Norwood procedure with continuous intraoperative monitoring of CBF and cerebral oxygen saturation (StO₂) using two non-invasive optical techniques, namely diffuse correlation spectroscopy (DCS) and frequency-domain diffuse optical spectroscopy (FD-DOS). Changes in CBF and StO₂ due to ACP were calculated by comparing these parameters during a stable 5 min period of ACP to the last 5 min of full-body CPB immediately prior to ACP initiation. Flow rates for ACP were left to the discretion of the surgeon and ranged from 30 to 50 ml/kg/min, and all subjects were cooled to 18°C prior to initiation of ACP.

Results

During ACP, the continuous optical monitoring demonstrated a median (IQR) percent change in CBF of -43.4% (38.6) and a median (IQR) absolute change in StO₂ of -3.6% (12.3) compared to a baseline period during full-body cardiopulmonary bypass (CPB). The four subjects demonstrated varying responses in StO₂ due to ACP. ACP flow rates of 30 and 40 ml/kg/min (n = 3) were associated with decreased CBF during ACP compared to full-body CPB. Conversely, one subject with a higher flow6Di rate of 50 ml/kg/min demonstrated increased CBF and StO₂ during ACP.

Conclusions

This feasibility study demonstrates that novel diffuse optical technologies can be utilized for improved neuromonitoring in neonates undergoing cardiac surgery where ACP is utilized. Future studies are needed to correlate these findings with neurological outcomes to inform best practices during ACP in these high-risk neonates.

Perioperative EEG background and discharge abnormalities in children undergoing cardiac surgery: a prospective single-centre observational study

BACKGROUND

We analysed the characteristics of abnormal electroencephalogram (EEG) patterns before, during, and 48 h after cardiac surgery in patients with heterogeneous congenital heart disease to assess their relationship to demographic and perioperative variables and to early patient outcomes.

METHODS

In 437 patients enrolled in a single centre, EEG was evaluated for background (including sleep-wake cycle) and discharge (seizures, spikes/sharp waves, pathological delta brushes) abnormalities. Clinical data (arterial blood pressure, doses of inotropic drugs, and serum lactate concentrations) were recorded every 3 h. Postoperative brain MRI was performed before discharge.

RESULTS

Preoperative, intraoperative, and postoperative EEG was monitored in 139, 215, and 437 patients, respectively. Patients with a degree of preoperative background abnormalities (n=40) had more severe intraoperative and postoperative EEG abnormalities (P<0.0001). Intraoperatively, 106/215 (49.3%) patients progressed into an isoelectric EEG. Longer durations of isoelectric EEG were associated with more severe postoperative EEG abnormalities and brain injury on MRI (Ps≤0.003). Postoperative background abnormalities occurred in 218/437 (49.9%) patients, and 119 (54.6%) of them had not recovered after surgery. Seizures occurred in 36/437 (8.2%) patients, spikes/sharp waves in 359/437 (82.2%), and pathological delta brushes in 9/437 (2.0%). Postoperative EEG abnormalities correlated with degree of brain injury on MRI (Ps≤0.02). Demographic and perioperative variables were significantly correlated with postoperative EEG abnormalities, which in turn correlated with adverse clinical outcomes.

CONCLUSIONS

Perioperative EEG abnormalities occurred frequently and correlated with numerous demographic and perioperative variables and adversely correlated with postoperative EEG abnormalities and early outcomes. The relation of EEG background and discharge abnormalities with long-term neurodevelopmental outcomes remains to be explored.

Cannabinoid Receptor Agonist WIN55, 212-2 Attenuates Injury in the Hippocampus of Rats after Deep Hypothermic Circulatory Arrest

OBJECTIVES

Postoperative neurological deficits remain a challenge in cardiac surgery employing deep hypothermic circulatory arrest (DHCA). This study aimed to investigate the effect of WIN55, 212-2, a cannabinoid agonist, on brain injury in a rat model of DHCA.

METHODS

Twenty-four male Sprague Dawley rats were randomly divided into three groups: a control group (which underwent cardiopulmonary bypass (CPB) only), a DHCA group (CPB with DHCA), and a WIN group (WIN55, 212-2 pretreatment before CPB with DHCA). Histopathological changes in the brain were evaluated by hematoxylin-eosin staining. Plasma levels of superoxide dismutase (SOD) and proinflammatory cytokines including interleukin (IL)-1β, IL-6, and tumor necrosis factor-alpha (TNF-a) were determined using an enzyme-linked immunosorbent assay (ELISA). The expression of SOD in the hippocampus was detected by Western blot and immunofluorescence staining. Levels of apoptotic-related protein caspase-3 and type 1 cannabinoid receptor (CB1R) in the hippocampus were evaluated by Western blot.

RESULTS

WIN55, 212-2 administration attenuated histopathological injury of the hippocampus in rats undergoing DHCA, associated with lowered levels of IL-1β, IL-6, and TNF-α (p < 0.05, p < 0.001, and p < 0.01, vs. DHCA, respectively) and an increased level of SOD (p < 0.05 vs. DHCA). WIN55, 212-2 treatment also increased the content of SOD in the hippocampus. The protein expression of caspase-3 was downregulated and the expression of CB1R was upregulated in the hippocampus by WIN55, 212-2.

CONCLUSIONS

the administration of WIN55, 212-2 alleviates hippocampal injury induced by DHCA in rats by regulating intrinsic inflammatory and oxidative stress responses through a CB1R-dependent mechanism.

Incidence of Acute Neurological Events in Neonates and Infants Undergoing Cardiac Surgery Using a High-Hematocrit/ High-Flow Bypass Strategy

Background: The incidence of new acute neurological injury occurring in neonates and infants during cardiac surgery utilizing cardiopulmonary bypass is reportedly 3% to 5%. In 2013, we adopted a high flow rate, and high hematocrit bypass strategy, and sought to assess the incidence of early neurological injuries associated with this strategy. Methods: Neonates and infants undergoing cardiopulmonary bypass between January 2013 and December 2019 (n  =  714) comprise the study. Adverse neurological events (ANEs) were defined as any abnormality of pupils, delayed awakening, seizures, focal neurological deficits, concerns prompting neurological consultation, or any abnormality on neurological imaging in the postoperative period. Our bypass strategy included a high flow rate (150-200 mL/kg/min), without reduction of flow rates during cooling and maintaining a target hematocrit on bypass > 32% with a terminal hematocrit of > 42%. Results: Median weight at the time of the procedure was 4.6 kg (IQR 3.6-6.1 kg) with the smallest patient weighing 1.36 kg. There were 46 premature patients (6.4%). There were 149 patients (20.9%) patients who underwent deep hypothermic circulatory arrest with a median time of 26 min (IQR 21-41 min). Hospital mortality was 3.5% (24/714, 95% CI: 2.28-5.13). The incidence of neurological events as defined above was 0.84% (6/714, 95% CI: 0.31-1.82). Neurological imaging identified ischemic injury in 4 patients and intraventricular hemorrhage in 2. Conclusions: High flow/high hematocrit bypass strategy was associated with a low incidence of ANE in this vulnerable population.

Pulmonary Venous Gradients in Healthy Controls and Following the Repair of Total Anomalous Pulmonary Venous Return

The percent of children who can achieve a normal and physiologic pulmonary venous gradient and flow following the repair of Total Anomalous Pulmonary Venous Return (TAPVR) is not known. Pulmonary venous confluence gradients from infants with supra-, infra-, or mixed TAPVR, repaired using a direct anastomotic connection were measured. Data from age, weight, and gender-matched controls established the normal pulmonary venous gradient range (0.30-0.94 mmHg). TAPVR subjects were divided into three groups: (I) pulmonary venous gradient < 2 × normal with multiphasic flow (II) pulmonary venous gradient > 2 × normal with multiphasic flow, and (III) pulmonary venous gradient > 2 × normal with monophasic flow. From 63 children following TAPVR repair and 63 matched controls, pulmonary venous gradients were significantly lower [0.5 mmHg (IQR:0.4, 0.6) vs 1.6 mmHg (IQR:1.0, 2.4); p < 0.001], and multiphasic flow more frequent (100 vs. 84.1%; p = 0.001) within the control group. There were 38 children (60.3%) in group I, 15 (23.8%) in group II, and 10 (15.8%) in group III. Children in Group I were significantly older at the time of repair, had shorter cardiopulmonary bypass times, and did not utilize deep hypothermic circulatory arrest (DHCA). Multivariate analysis confirmed that avoiding DHCA [Odds Ratio 0.931 (0.913,0.994; p = 0.002)] and shorter cardiopulmonary bypass times [Odds Ratio 0.962 (0.861,0.968; p = 0.02)] during repair were associated with the lowest pulmonary venous gradients and multiphasic flow. Following TAPVR repair with a direct anastomosis, the majority of children can achieve a gradient two times normal or less with multiphasic pulmonary venous flow.

Inhibition of the Activating Transcription Factor 6 Branch of Endoplasmic Reticulum Stress Ameliorates Brain Injury after Deep Hypothermic Circulatory Arrest

Neurological dysfunction is a common complication of deep hypothermic circulatory arrest (DHCA). Endoplasmic reticulum (ER) stress plays a role in neuronal ischemia-reperfusion injury; however, it is unknown whether it contributes to DHCA-induced brain injury. Here, we aimed to investigate the role of ER stress in a rat DHCA model and cell hypothermic oxygen-glucose deprivation reoxygenation (OGD/R) model. ER stress and apoptosis-related protein expression were identified using Western blot analysis. Cell counting assay-8 and flow cytometry were used to determine cell viability and apoptosis, respectively. Brain injury was evaluated using modified neurological severity scores, whereas brain injury markers were detected through histological examinations and immunoassays. We observed significant ER stress molecule upregulation in the DHCA rat hippocampus and in hypothermic OGD/R PC-12 cells. In vivo and in vitro experiments showed that ER stress or activating transcription factor 6 (ATF6) inhibition alleviated rat DHCA-induced brain injury, increased cell viability, and decreased apoptosis accompanied by C/EBP homologous protein (CHOP). ER stress is involved in DHCA-induced brain injury, and the inhibition of the ATF6 branch of ER stress may ameliorate this injury by inhibiting CHOP-mediated apoptosis. This study establishes a scientific foundation for identifying new therapeutic targets for perioperative brain protection in clinical DHCA.

Impact of cardiac surgical timing on the neurodevelopmental outcomes of newborns with Complex congenital heart disease (CHD)

Background

More than half of infants with complex congenital heart disease (CHD) will have a neurodevelopmental disorder of multifactorial causes. The preoperative period represents a time-window during which neonates with complex CHD are in a state of hypoxia and hemodynamic instability, which fosters the emergence of brain injuries and, thus, affects early brain networks and neurodevelopmental outcomes. Currently, there is no consensus regarding the optimal age for cardiac surgery in terms of neurodevelopmental outcomes, and its definition is a real challenge. Our aim is to determine the relationship between cardiac surgical timing and long-term neurodevelopmental outcomes for various types of complex CHD.

Methods

We hypothesize that earlier surgical timing could represent a neuroprotective strategy that reduces perioperative white matter injuries (WMIs) and postoperative morbidity, leading to improved neurodevelopmental outcomes in infants with complex CHD. Firstly, our prospective study will allow us to determine the correlation between age at the time of surgery (days of life) and neurodevelopmental outcomes at 24 months. We will then analyze the correlation between age at surgery and (i) the incidence of WMIs (through pre- and postoperative MRIs), (ii) postoperative morbidity, and (iii) the duration of the hospital stay.

Implications and Dissemination

This research protocol was registered in the Clinical Trial Registry (National Clinical Trial: NCT04733378). This project aims to help launch the first Neurocardiac Investigation Clinic in Marseille - AP-HM - to propose an overall personalized monitoring and treatment program for patients operated on for complex CHD.

Perioperative Course and Socioeconomic Status Predict Long-Term Neurodevelopment Better Than Perioperative Conventional Neuroimaging in Children with Congenital Heart Disease

OBJECTIVE

The objective of the study was to compare the use of neonatal conventional brain magnetic resonance imaging (MRI) with that of clinical factors and socioeconomic status (SES) to predict long-term neurodevelopment in children with severe congenital heart disease (CHD).

STUDY DESIGN

In this prospective cohort study, perioperative MRIs were acquired in 57 term-born infants with CHD undergoing cardiopulmonary bypass surgery during their first year of life. Total brain volume (TBV) was measured using an automated method. Brain injury severity (BIS) was assessed by an established scoring system. The neurodevelopmental outcome was assessed at 6 years using standardized test batteries. A multiple linear regression model was used for cognitive and motor outcomes with postoperative TBV, perioperative BIS, CHD complexity, length of hospital stay, and SES as covariates.

RESULTS

CHD diagnoses included univentricular heart defect (n = 15), transposition of the great arteries (n = 33), and acyanotic CHD (n = 9). Perioperative moderate-to-severe brain injury was detected in 15 (26%) patients. The total IQ was similar to test norms (P = .11), whereas the total motor score (P < .001) was lower. Neither postoperative TBV nor perioperative BIS predicted the total IQ, but SES (P < .001) and longer hospital stay (P = .004) did. No factor predicted the motor outcome.

CONCLUSION

Although the predictive value of neonatal conventional MRIs for long-term neurodevelopment is low, duration of hospital stay and SES better predict the outcome in this CHD sample. These findings should be considered in initiating early therapeutic support.

Early Determinants of Adverse Motor Outcomes in Preschool Children with a Critical Congenital Heart Defect

Neurodevelopmental disabilities are common in infants with critical congenital heart disease (CCHD). A prospective, longitudinal cohort study was conducted to establish the prevalence and early determinants of adverse motor outcomes in infants who underwent cardiac surgery with cardiopulmonary bypass before six months of age. Motor development was assessed in 147 preschoolers using the Movement Assessment Battery for children-II. Although the majority displayed an average motor development, 22% of preschool children with CCHD deteriorated in their motor developmental score compared to their previous assessment at 18 months, especially in those with an aortic arch anomaly (AAA) (35%). Individual stability over time appeared to be moderate and the number of children with a motor delay increased, up to 20% in children with AAA. Motor development up to 42 months was best predicted by gestational age, cardio pulmonary bypass time, aortic cross clamp time, number of heart catheterizations up to 18 months and early motor outcomes. The increase in number of preschool children with a motor delay underlines the importance of longitudinal screening of motor skills in children with CCHD at risk for adverse motor outcomes. Offering early interventions may protect their current and future cardiovascular health as motor development is an independent predictor of exercise capacity, physical activity and participation in daily living.

Perioperative electroencephalography in cardiac surgery with hypothermic circulatory arrest: a narrative review

OBJECTIVES

Cardiac surgery with hypothermic circulatory arrest (HCA) is associated with neurological morbidity of variable severity and electroencephalography (EEG) is a sensitive proxy measure of brain injury. We conducted a narrative review of the literature to evaluate the role of perioperative EEG monitoring in cardiac surgery involving HCA.

METHODS

Medline, Embase, Central and LILACS databases were searched to identify studies utilizing perioperative EEG during surgery with HCA in all age groups, published since 1985 in any language. We aimed to compare EEG use with no use but due to the lack of comparative studies, we performed a narrative review of its utility. Two or more reviewers independently screened studies for eligibility and extracted data.

RESULTS

Fourty single-centre studies with a total of 3287 patients undergoing surgery were identified. Most were observational cohort studies (34, 85%) with only 1 directly comparing EEG use with no use. EEG continuity (18, 45%), seizures (15, 38%) and electrocerebral inactivity prior to circulatory arrest (15, 38%) were used to detect, monitor, prevent and prognose neurological injury. Neurological dysfunction was reported in almost all studies and occurred in 0–21% of patients. However, the heterogeneity of reported clinical and EEG outcome measures prevented meta-analysis.

CONCLUSIONS

EEG is used to detect cortical ischaemia and seizures and predict neurological abnormalities and may guide intraoperative cerebral protection. However, there is a lack of comparative data demonstrating the benefit of perioperative EEG monitoring. Use of a standardized methodology for performing EEG and reporting outcome metrics would facilitate the conduct of high-quality clinical trials.

Growth of unrepaired hypoplastic proximal aortic arch and reintervention rate after aortic coarctation repair

BACKGROUND

Treatment of tubular hypoplasia of the aortic arch (THAA) associated with aortic coarctation (CoA) remains controversial. We aimed to evaluate growth of unrepaired hypoplastic proximal aortic arches (PAAs) after surgical repair for CoA.

METHODS

Preoperative and follow-up echocardiographic images of 139 patients who underwent CoA repairs from 2005 to 2012 were reviewed. THAA was defined as PAA z-score <-3 and non-THAA group z-score ≥-3. Reintervention rates due to aortic obstruction were assessed using competing risk models and diameters of the aorta were compared with Mann-Whitney U tests.

RESULTS

Fifty patients (36%) had THAA and 89 (64%) had non-THAA. The survival rate was 94% at 10 years. The overall reintervention rate at 10 years was 9% in the THAA group and 16% in the non-THAA group (P = .54). The catheter reintervention rate at ten years was 2% in the THAA group and 16% in the non-THAA group (P = .031). The surgical reintervention rate at ten years was 7% in the THAA group and 0% in the non-THAA group (P = .016). All 4 patients who required surgical reintervention were in the THAA group and 3 patients with PAA obstruction had preoperative PAA z-scores -3.6, -4.2, and -4.3. Follow-up echocardiograms showed PAA catch-up growth in the THAA group compared with the non-THAA group (preoperative z-score of -3.6 vs -2.3, and at 7 years of -1.1 vs -1.2; P < .001).

CONCLUSIONS

Unrepaired PAA hypoplasia grows after CoA repair. Reintervention rates were comparable between groups but those with THAA had higher surgical reintervention rates.

Paediatric brain MRI findings following congenital heart surgery: a systematic review

OBJECTIVE

This systematic review aimed to establish the relative incidence of new postoperative brain MRI findings following paediatric congenital cardiac surgery.

DESIGN

To distinguish perioperative changes from pre-existing MR findings, our systematic search strategy focused on identifying original research studies reporting both presurgery and postsurgery brain MRI scans. Patient demographics, study methods and brain MR findings were extracted.

RESULTS

Twenty-one eligible publications, including two case-control and one randomised controlled trial, were identified. Pre-existing brain MRI findings were noted in 43% (513/1205) of neonates prior to surgery, mainly white matter injuries (WMI). Surgery was performed at a median age of 8 days with comparison of preoperative and postoperative MR scans revealing additional new postoperative findings in 51% (550/1075) of patients, mainly WMI. Four studies adopted a brain injury scoring system, but the majority did not indicate the severity or time course of findings. In a subgroup analysis, approximately 32% of patients with pre-existing lesions went on to develop additional new lesions postsurgery. Pre-existing findings were not found to confer a higher risk of acquiring brain lesions postoperatively. No evidence was identified linking new MR findings with later neurodevelopmental delay.

CONCLUSION

This systematic review suggests that surgery approximately doubles the number of patients with new brain lesions.

Correlation of Cerebral Microdialysis with Non-Invasive Diffuse Optical Cerebral Hemodynamic Monitoring during Deep Hypothermic Cardiopulmonary Bypass

Neonates undergoing cardiac surgery involving aortic arch reconstruction are at an increased risk for hypoxic-ischemic brain injury. Deep hypothermia is utilized to help mitigate this risk when periods of circulatory arrest are needed for surgical repair. Here, we investigate correlations between non-invasive optical neuromonitoring of cerebral hemodynamics, which has recently shown promise for the prediction of postoperative white matter injury in this patient population, and invasive cerebral microdialysis biomarkers. We compared cerebral tissue oxygen saturation (StO₂), relative total hemoglobin concentration (rTHC), and relative cerebral blood flow (rCBF) measured by optics against the microdialysis biomarkers of metabolic stress and injury (lactate–pyruvate ratio (LPR) and glycerol) in neonatal swine models of deep hypothermic cardiopulmonary bypass (DHCPB), selective antegrade cerebral perfusion (SACP), and deep hypothermic circulatory arrest (DHCA). All three optical parameters were negatively correlated with LPR and glycerol in DHCA animals. Elevation of LPR was found to precede the elevation of glycerol by 30–60 min. From these data, thresholds for the detection of hypoxic-ischemia-associated cerebral metabolic distress and neurological injury are suggested. In total, this work provides insight into the timing and mechanisms of neurological injury following hypoxic-ischemia and reports a quantitative relationship between hypoxic-ischemia severity and neurological injury that may inform DHCA management.

CeRebrUm and CardIac Protection with ALlopurinol in Neonates with Critical Congenital Heart Disease Requiring Cardiac Surgery with Cardiopulmonary Bypass (CRUCIAL): study protocol of a phase III, randomized, quadruple-blinded, placebo-controlled, Dutch multicenter trial

Background

Neonates with critical congenital heart disease (CCHD) undergoing cardiac surgery with cardiopulmonary bypass (CPB) are at risk of brain injury that may result in adverse neurodevelopment. To date, no therapy is available to improve long-term neurodevelopmental outcomes of CCHD neonates. Allopurinol, a xanthine oxidase inhibitor, prevents the formation of reactive oxygen and nitrogen species, thereby limiting cell damage during reperfusion and reoxygenation to the brain and heart. Animal and neonatal studies suggest that allopurinol reduces hypoxic-ischemic brain injury and is cardioprotective and safe. This trial aims to test the hypothesis that allopurinol administration in CCHD neonates will result in a 20% reduction in moderate to severe ischemic and hemorrhagic brain injury.

Methods

This is a phase III, randomized, quadruple-blinded, placebo-controlled, multicenter trial. Neonates with a prenatal or postnatal CCHD diagnosis requiring cardiac surgery with CPB in the first 4 weeks after birth are eligible to participate. Allopurinol or mannitol-placebo will be administered intravenously in 2 doses early postnatally in neonates diagnosed antenatally and 3 doses perioperatively of 20 mg/kg each in all neonates. The primary outcome is a composite endpoint of moderate/severe ischemic or hemorrhagic brain injury on early postoperative MRI, being too unstable for postoperative MRI, or mortality within 1 month following CPB. A total of 236 patients (n = 188 with prenatal diagnosis) is required to demonstrate a reduction of the primary outcome incidence by 20% in the prenatal group and by 9% in the postnatal group (power 80%; overall type 1 error controlled at 5%, two-sided), including 1 interim analysis at n = 118 (n = 94 with prenatal diagnosis) with the option to stop early for efficacy. Secondary outcomes include preoperative and postoperative brain injury severity, white matter injury volume (MRI), and cardiac function (echocardiography); postnatal and postoperative seizure activity (aEEG) and regional cerebral oxygen saturation (NIRS); neurodevelopment at 3 months (general movements); motor, cognitive, and language development and quality of life at 24 months; and safety and cost-effectiveness of allopurinol.

Discussion

This trial will investigate whether allopurinol administered directly after birth and around cardiac surgery reduces moderate/severe ischemic and hemorrhagic brain injury and improves cardiac function and neurodevelopmental outcome in CCHD neonates.

Trial registration

EudraCT 2017-004596-31. Registered on November 14, 2017. ClinicalTrials.gov NCT04217421. Registered on January 3, 2020

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-022-06098-y.

S100B in cardiac surgery brain monitoring: friend or foe?

Recent advances in perioperative management of adult and pediatric patients requiring open heart surgery (OHS) and cardiopulmonary bypass (CPB) for cardiac and/or congenital heart diseases repair allowed a significant reduction in the mortality rate. Conversely morbidity rate pattern has a flat trend. Perioperative period is crucial since OHS and CPB are widely accepted as a deliberate hypoxic-ischemic reperfusion damage representing the cost to pay at a time when standard of care monitoring procedures can be silent or unavailable. In this respect, the measurement of neuro-biomarkers (NB), able to detect at early stage perioperative brain damage could be especially useful. In the last decade, among a series of NB, S100B protein has been investigated. After the first promising results, supporting the usefulness of the protein as predictor of short/long term adverse neurological outcome, the protein has been progressively abandoned due to a series of limitations. In the present review we offer an up-dated overview of the main S100B pros and cons in the peri-operative monitoring of adult and pediatric patients.

Neurodevelopmental and Mental Health Outcomes in Patients With Fontan Circulation: A State-of-the-Art Review

Children, adolescents and adults living with Fontan circulation face numerous neurological and developmental challenges. As the population with complex CHD increases thanks to outstanding improvement in medical and surgical care, the long-term developmental and mental health sequelae have become a public health priority in pediatric and congenital cardiology. Many patients with a Fontan circulation experience difficulty in areas of cognition related to attention and executive functioning, visual spatial reasoning and psychosocial development. They are also at high risk for mental health morbidities, particularly anxiety disorders and depression. Several hemodynamic risk factors, beginning during the fetal period, may influence outcomes and yield to abnormal brain growth and development. Brain injury such as white matter lesions, stroke or hemorrhage can occur before, during, or after surgery. Other sociodemographic and surgical risk factors such as multiple catheterizations and surgeries and prolonged hospital stay play a detrimental role in patients' neurodevelopmental prognosis. Prevention and intervention to optimize long-term outcomes are critical in the care of this vulnerable population with complex CHD.

Does supply meet demand? A comparison of perfusion strategies on cerebral metabolism in a neonatal swine model

OBJECTIVE

We aimed to determine the effects of selective antegrade cerebral perfusion compared with other perfusion strategies on indices of cerebral blood flow, oxygenation, cellular stress, and mitochondrial function.

METHODS

One-week-old piglets (n = 41) were assigned to 5 treatment groups. Thirty-eight were placed on cardiopulmonary bypass. Of these, 30 were cooled to 18°C and underwent deep hypothermic circulatory arrest (n = 10), underwent selective antegrade cerebral perfusion at 10 mL/kg/min (n = 10), or remained on continuous cardiopulmonary bypass (deep hypothermic cardiopulmonary bypass, n = 10) for 40 minutes. Other subjects remained on normothermic cardiopulmonary bypass (n = 8) or underwent sham surgery (n = 3). Novel, noninvasive optical measurements recorded cerebral blood flow, cerebral tissue oxyhemoglobin concentration, oxygen extraction fraction, total hemoglobin concentration, and cerebral metabolic rate of oxygen. Invasive measurements of cerebral microdialysis and cerebral blood flow were recorded. Cerebral mitochondrial respiration and reactive oxygen species generation were assessed after the piglets were killed.

RESULTS

During hypothermia, deep hypothermic circulatory arrest piglets experienced increases in oxygen extraction fraction (P < .001), indicating inadequate matching of oxygen supply and demand. Deep hypothermic cardiopulmonary bypass had higher cerebral blood flow (P = .046), oxyhemoglobin concentration (P = .019), and total hemoglobin concentration (P = .070) than selective antegrade cerebral perfusion, indicating greater oxygen delivery. Deep hypothermic circulatory arrest demonstrated worse mitochondrial function (P < .05), increased reactive oxygen species generation (P < .01), and increased markers of cellular stress (P < .01). Reactive oxygen species generation was increased in deep hypothermic cardiopulmonary bypass compared with selective antegrade cerebral perfusion (P < .05), but without significant microdialysis evidence of cerebral cellular stress.

CONCLUSIONS

Selective antegrade cerebral perfusion meets cerebral metabolic demand and mitigates cerebral mitochondrial reactive oxygen species generation. Excess oxygen delivery during deep hypothermia may have deleterious effects on cerebral mitochondria that may contribute to adverse neurologic outcomes. We describe noninvasive measurements that may help guide perfusion strategies.

Association of Ongoing Cerebral Oxygen Extraction During Deep Hypothermic Circulatory Arrest With Postoperative Brain Injury

Cardiac surgery utilizing circulatory arrest is most commonly performed under deep hypothermia (∼18°C) to suppress tissue oxygen demand and provide neuroprotection during operative circulatory arrest. Studies investigating the effects of deep hypothermic circulatory arrest (DHCA) on neurodevelopmental outcomes of patients with congenital heart disease give conflicting results. Here, we address these issues by quantifying changes in cerebral oxygen saturation, blood flow, and oxygen metabolism in neonates during DHCA and investigating the association of these changes with postoperative brain injury. Neonates with critical congenital heart disease undergoing DHCA were recruited for continuous intraoperative monitoring of cerebral oxygen saturation (ScO₂) and an index of cerebral blood flow (CBF_i) using 2 noninvasive optical techniques, diffuse optical spectroscopy (DOS) and diffuse correlation spectroscopy (DCS). Pre- and postoperative brain magnetic resonance imaging (MRI) was performed to detect white matter injury (WMI). Fifteen neonates were studied, and 11/15 underwent brain MRI. During DHCA, ScO₂ decreased exponentially in time with a median decay rate of -0.04 min^-1. This decay rate was highly variable between subjects. Subjects who had larger decreases in ScO₂ during DHCA were more likely to have postoperative WMI (P = 0.02). Cerebral oxygen extraction persists during DHCA and varies widely from patient-to-patient. Patients with a higher degree of oxygen extraction during DHCA were more likely to show new WMI in postoperative MRI. These findings suggest cerebral oxygen extraction should be monitored during DHCA to identify patients at risk for hypoxic-ischemic injury, and that current commercial cerebral oximeters may underestimate cerebral oxygen extraction.

Identifying lncRNA- and Transcription Factor-Associated Regulatory Networks in the Cortex of Rats With Deep Hypothermic Circulatory Arrest

Long noncoding RNAs (lncRNAs) and microRNAs (miRNAs) are involved in the mechanism underlying cerebral dysfunction after deep hypothermic circulatory arrest (DHCA), although the exact details have not been elucidated. To explore the expression profiles of lncRNAs and miRNAs in DHCA cerebral injury, we determined the lncRNA, miRNA and mRNA expression profiles in the cerebral cortex of DHCA and sham rats. First, a rat model of DHCA was established, and high-throughput sequencing was performed to analyze the differentially expressed RNAs (DERNAs). Then, the principal functions of the significantly deregulated genes were identified using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses. Expression networks (lncRNAs-miRNAs-mRNAs and transcription factors (TFs)-miRNAs-mRNAs) were also established. Finally, the expression of DERNAs was confirmed by quantitative real-time PCR (RT-qPCR). We identified 89 lncRNAs, 45 miRNAs and 59 mRNAs between the DHCA and sham groups and constructed a comprehensive competitive endogenous RNAs (ceRNAs) network. A TF-miRNA-mRNA regulatory network was also established. Finally, we predicted that Lcorl-miR-200a-3p-Ttr, BRD4-Ccl2 and Ep300-miR-200b-3p-Tmem72 may participate in the pathogenesis of DHCA cerebral injury.

A Uniform Description of Perioperative Brain MRI Findings in Infants with Severe Congenital Heart Disease: Results of a European Collaboration

BACKGROUND AND PURPOSE

A uniform description of brain MR imaging findings in infants with severe congenital heart disease to assess risk factors, predict outcome, and compare centers is lacking. Our objective was to uniformly describe the spectrum of perioperative brain MR imaging findings in infants with congenital heart disease.

MATERIALS AND METHODS

Prospective observational studies were performed at 3 European centers between 2009 and 2019. Brain MR imaging was performed preoperatively and/or postoperatively in infants with transposition of the great arteries, single-ventricle physiology, or left ventricular outflow tract obstruction undergoing cardiac surgery within the first 6 weeks of life. Brain injury was assessed on T1, T2, DWI, SWI, and MRV. A subsample of images was assessed jointly to reach a consensus.

RESULTS

A total of 348 MR imaging scans (180 preoperatively, 168 postoperatively, 146 pre- and postoperatively) were obtained in 202 infants. Preoperative, new postoperative, and cumulative postoperative white matter injury was identified in 25%, 30%, and 36%; arterial ischemic stroke, in 6%, 10%, and 14%; hypoxic-ischemic watershed injury in 2%, 1%, and 1%; intraparenchymal cerebral hemorrhage, in 0%, 4%, and 5%; cerebellar hemorrhage, in 6%, 2%, and 6%; intraventricular hemorrhage, in 14%, 6%, and 13%; subdural hemorrhage, in 29%, 17%, and 29%; and cerebral sinovenous thrombosis, in 0%, 10%, and 10%, respectively.

CONCLUSIONS

A broad spectrum of perioperative brain MR imaging findings was found in infants with severe congenital heart disease. We propose an MR imaging protocol including T1-, T2-, diffusion-, and susceptibility-weighted imaging, and MRV to identify ischemic, hemorrhagic, and thrombotic lesions observed in this patient group.

Motor Developmental Delay After Cardiac Surgery in Children With a Critical Congenital Heart Defect: A Systematic Literature Review and Meta-analysis

PURPOSE

To systematically review evidence regarding the severity and prevalence of motor development in children with a critical congenital heart defect (CCHD) without underlying genetic anomalies.

SUMMARY OF KEY POINTS

Twelve percent of all included studies reported abnormal mean motor developmental scores, and 38% reported below average motor scores. Children with single-ventricle physiology, especially those with hypoplastic left heart syndrome, had the highest severity and prevalence of motor delay, particularly at 0 to 12 months. Most included studies did not differentiate between gross and fine motor development, yet gross motor development was more affected.

RECOMMENDATIONS FOR CLINICAL PRACTICE

We recommend clinicians differentiate between the type of heart defect, fine and gross motor development, and the presence of genetic anomalies. Furthermore, increased knowledge about severity and prevalence will enable clinicians to tailor their interventions to prevent motor development delays in CCHD.

An introduction to and review of cardiac neurodevelopment: the risks and recommended approaches

PURPOSE OF REVIEW

To introduce the reader to the current understanding of the neurocognitive profile of congenital heart disease (CHD) survivors, the risk factors that may influence outcomes, and to the recommendations for cardiac neurodevelopmental care.

RECENT FINDINGS

A growing body of literature has shown that survivors of CHD are at increased risk for neurodevelopmental impairments. Multiple elements influence each patient's risk, which likely begins in utero and extends to perioperative management, surgical considerations, and long-term clinical care. Additionally, sociodemographic factors may compound these risks. Serial developmental follow-up is recommended for children with critical CHD.

SUMMARY

Though there are some clinical factors that increase risk, based on the high rate of developmental impairments for children with CHD, serial evaluations are recommended. Multidisciplinary and multicenter collaboration is ongoing and will facilitate moving this field forward to improve neurodevelopmental outcomes for children with CHD.

Perioperative GABA Blood Concentrations in Infants with Cyanotic and Non-Cyanotic Congenital Heart Diseases

Perioperative stress detection in children with congenital heart disease (CHD), particularly in the brain, is still limited. Among biomarkers, γ-amino-aminobutyric acid (GABA) assessment in biological fluids appears to be promising for its regulatory action on the cardiovascular and cerebral systems. We aimed to investigate cyanotic (C) or non-cyanotic (N) CHD children for GABA blood level changes in the perioperative period. We conducted an observational study in 68 CHD infants (C: n = 33; N: n = 35) who underwent perioperative clinical, standard laboratory and monitoring parameter recordings and GABA assessment. Blood samples were drawn at five predetermined time-points before, during and after surgery. No significant perioperative differences were observed between groups in clinical and laboratory parameters. In C, perioperative GABA levels were significantly lower than N. Arterial oxygen saturation and blood concentration significantly differed between C and N children and correlated at cardiopulmonary by-pass (CPB) time-point with GABA levels. The present data showing higher hypoxia/hyperoxia-mediated GABA concentrations in C children suggest that they are more prone to perioperative cardiovascular and brain stress/damage. The findings suggest the usefulness of further investigations to detect the “optimal” oxygen concentration target in order to avoid the side effects associated with re-oxygenation during CPB.

Impact of hepatopathy in pediatric patients after surgery for complex congenital heart disease

Patients undergoing complex pediatric cardiac surgery in early infancy are at risk of postoperative secondary end-organ dysfunction. The aim of this study was to determine specific risk factors promoting the development of peri- and postoperative hepatopathy after surgery for congenital heart disease. In this retrospective study, we identified 20 consecutive patients operated between 2011 and 2019 from our institutional cohort who developed significant postsurgical hepatic dysfunction. These patients were compared to a control group of 30 patients with comparable initial cardiac conditions and STS-EACTS risk score. Patients who developed hepatopathy in the intensive care unit have chronic cholestasis and decreased liver synthesis. The impact of postoperative hepatopathy on morbidity was marked. In six patients (30%), liver transplantation was executed as ultima ratio, and two (10%) were listed for liver transplantation. The overall mortality related to postoperative hepatopathy is high: We found nine patients (45%) having severe hepatopathy and mostly multiple organ dysfunction who died in the postoperative course. According to risk analysis, postoperative right and left heart dysfunction in combination with a postoperative anatomical residuum needing a re-operation or re-intervention in the postoperative period is associated with a high risk for the development of cardiac hepatopathy. Furthermore, postoperative complications (pleural effusion, heart rhythm disorders, etc.), postoperative infections, and the need for parenteral nutrition also raise the risk for cardiac hepatopathy. Further investigations are needed to reduce hepatic complications and improve the general prognosis of such complex patients.

Differential expression profiles of circular RNAs in the rat hippocampus after deep hypothermic circulatory arrest

Neurological dysfunction commonly occurs after cardiac surgery with deep hypothermic circulatory arrest (DHCA). The mechanisms underlying DHCA-associated brain injury remain poorly understood. This study determined the changes in expression profiles of circular RNAs (circRNAs) in the hippocampus in rats that underwent DHCA, with an attempt to explore the potential role of circRNAs in the brain injury associated with DHCA. Adult male Sprague Dawley rats were subjected to cardiopulmonary bypass with DHCA. Brain injury was evaluated by neurological severity scores and histological as well as transmission electron microscope examinations. The expression profiles of circRNAs in the hippocampal tissues were screened by microarray. Quantitative real-time PCR (RT-qPCR) was used to validate the reliability of the microarray results. Bioinformatic algorithms were applied to construct a competing endogenous RNA (ceRNA) network, and Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were performed to explore the potential biological roles of the circRNAs. Out of 14 145 circRNAs screened, 56 were differentially expressed in the hippocampus between the DHCA and sham-operated rats, including 30 upregulated and 26 downregulated circRNAs. The expression changes of six selected circRNAs (upregulated: rno_circRNA_011190, rno_circRNA_012988, rno_circRNA_000544; downregulated: rno_circRNA_010393, rno_circRNA_012043, rno_circRNA_015149) were further confirmed by RT-qPCR. Bioinformatics analysis showed the enrichment of these confirmed circRNAs and their potential target mRNAs in several KEGG pathways including histidine metabolism, adipocytokine signaling, and cAMP signaling. By revealing the change expression profiles of circRNAs in the brain after DHCA, this study indicates possible involvements of these dysregulated circRNAs in brain injury and suggests a potential of targeting circRNAs for prevention and treatment of neurological dysfunction associated with DHCA.

Use of carotid artery cannulation during redo sternotomy in congenital cardiac surgery: a single-centre experience

 

OBJECTIVES

Management of resternotomy is often a difficult challenge in patients with congenital diseases who have undergone multiple sternotomies. Our goal was to report our single-centre experience with carotid cannulation using a graft interposed during redo sternotomy in complex cardiac reintervention procedures.

METHODS

We performed a retrospective review of all patients who had undergone complex redo sternotomies between January 2019 and May 2020 utilizing a cervical cannulation technique with a Gore-Tex graft interposed on the carotid artery. We classified our population study on the basis of the primary diagnosis and the type of surgery. The primary outcomes of our analysis were the evaluation of the safety of the procedure in terms of survival and freedom from neurological events.

RESULTS

We analysed 22 patients who had undergone previous complex operations. The median age and weight at the time of reintervention were 130.35 (range 0.46-435) months and 31.5 (range 2.2-85) kg, respectively. Composite graft carotid cannulation provided adequate arterial flow in all patients with a median arterial flow of 3.5 l/min/m2 (range 0.6-6). One major cardiac injury occurred during sternotomy when emergency cardiopulmonary bypass (CPB) was initiated. Moreover, during their hospital stays, all patients had an uneventful recovery without neurological or vascular complications and no cervical wound infections.

CONCLUSIONS

Carotid cannulation using interposition of a side graft on the common carotid artery for arterial inflow is a reliable and safe method for initiation of CPB in complex redo surgeries in patients with congenital disease. Complications directly associated with this type of cannulation are uncommon and allow surgical re-entry with overall low risks.

Deep Hypothermic Circulatory Arrest in the Pediatric Population Undergoing Cardiac Surgery With Electroencephalography Monitoring: A Systematic Review and Meta-Analysis

OBJECTIVE

Cardiac surgery for repair of congenital heart defects poses unique hazards to the developing brain. Deep hypothermic circulatory arrest (DHCA) is a simple and effective method for facilitating a bloodless surgical field during congenital heart defect repair. There are, however, some concerns that prolonged DHCA increases the risk of nervous system injury. The electroencephalogram (EEG) is used in adult and, to a lesser extent, pediatric cardiac procedures as a neuromonitoring method. The present study was performed to assess outcomes following DHCA with EEG monitoring in the pediatric population.

DESIGN

In this systematic review and meta-analysis, the PubMed, Cochrane Central Register of Controlled Trials, Scopus, Institute of Science Index, and Embase databases were searched from inception for relevant articles. A fixed- or random-effects model, as appropriate, was used.

SETTING

Surgical setting.

PARTICIPANTS

Pediatric population (≤18 y old).

INTERVENTIONS

DHCA (18°C) with EEG monitoring.

MEASUREMENTS AND MAIN RESULTS

Nineteen articles with 1,267 pediatric patients ≤18 years were included. The event rate of clinical and EEG seizures among patients who underwent DHCA was 12.9% and 14.9%, respectively. Mortality was found to have a 6.3% prevalence. A longer duration of DHCA was associated with a higher risk of EEG seizure and neurologic abnormalities. In addition, seizures were associated with increased neurologic abnormalities and neurodevelopmental delay.

CONCLUSIONS

EEG and neurologic abnormalities were common after DHCA. A longer duration of DHCA was found to lead to more EEG seizure and neurologic abnormalities. Moreover, EEG seizures were more common than clinical seizures. Seizures were found to be associated with increased neurologic abnormalities and neurodevelopmental delay.

Interrelations of Intraoperative Changes in Cerebral Tissue Oxygen Saturation with Brain Volumes and Neurodevelopment Outcome After the Comprehensive Stage II Procedure in Infants With Hypoplastic Left Heart Syndrome: A Retrospective Cohort Study

OBJECTIVES

The monitoring of cerebral tissue oxygen saturation by near-infrared spectroscopy (S_cerebO₂) is used widely in pediatric cardiac anesthesia. However, little information is available on the effects of changes in perioperative S_cerebO₂ on brain morphology and neurologic outcome. The primary hypothesis tested in this study was that intraoperative S_cerebO₂ during the comprehensive stage II procedure correlated with brain volumes assessed by magnetic resonance imaging and neurodevelopmental scores.

DESIGN

Retrospective observational cohort study.

SETTING

University Hospital, Pediatric Heart Centre.

PATIENTS AND MEASUREMENTS

In 19 infants, the intraoperative course of S_cerebO₂ during the comprehensive stage II procedure was examined. Minimal S_cerebO₂ and integrated S_cerebO₂ below 45% (AUC) during surgery, as well as cerebral magnetic resonance imaging (MRI) examinations and Bayley III test at the ages of two-to-three years, were analyzed.

MAIN RESULTS

A positive correlation between minimal S_cerebO₂ and intracranial volume (p = 0.0243), total brain volume (p = 0.0243), and white matter volume (p = 0.0276) was observed, as was a negative correlation between AUC and intracranial volume (p = 0.0454) and white matter volume (p = 0.0381), respectively. No association was found between S_cerebO₂ and Bayley-III Score.

CONCLUSION

The correlation between S_cerebO₂ and brain volumes measured by MRI pointed out a possible importance of neuroprotective strategies aimed at optimizing S_cerebO₂ during complex congenital heart surgery. That no correlation between S_cerebO₂ and Bayley III Score was found suggested multifactorial causes for neurologic outcome in children with congenital heart defects.

A randomized trial comparing axillary versus innominate artery cannulation for aortic arch surgery

BACKGROUND

Cerebral protection remains the cornerstone of successful aortic surgery; however, there is no consensus as to the optimal strategy.

OBJECTIVE

To compare the safety and efficacy of innominate to axillary artery cannulation for delivering antegrade cerebral protection during proximal aortic arch surgery.

METHODS

This randomized controlled trial (The Aortic Surgery Cerebral Protection Evaluation CardioLink-3 Trial, ClinicalTrials.gov Identifier: NCT02554032), conducted across 6 Canadian centers between January 2015 and June 2018, allocated 111 individuals to innominate or axillary artery cannulation. The primary safety outcome was neuroprotection per the appearance of new severe ischemic lesions on the postoperative diffusion-weighted-magnetic resonance imaging. The primary efficacy outcome was the difference in total operative time. Secondary outcomes included 30-day all-cause mortality and postoperative stroke.

RESULTS

One hundred two individuals (mean age, 63 ± 11 years) were in the primary safety per-protocol analysis. Baseline characteristics between the groups were similar. New severe ischemic lesions occurred in 19 participants (38.8%) in the axillary versus 18 (34%) in the innominate group (P for noninferiority = .0009). Total operative times were comparable (median, 293 minutes; interquartile range, 222-411 minutes) for axillary versus (298 minutes; interquartile range, 231-368 minutes) for innominate (P for superiority = .47). Stroke/transient ischemic attack occurred in 4 (7.1%) participants in the axillary versus 2 (3.6%) in the innominate group (P = .43). Thirty-day mortality, seizures, delirium, and duration of mechanical ventilation were similar in both groups.

CONCLUSIONS

diffusion-weighted magnetic resonance imaging assessments indicate that antegrade cerebral protection with innominate cannulation is safe and affords similar neuroprotection to axillary cannulation during aortic surgery, although the burden of new neurological lesions is high in both groups.

Aortic Arch Enlargement and Coarctation Repair of Preserving the Lesser Curvature of the Aortic Arch Through a Left Thoracotomy in Neonates

The aim of this study was to analyze the aortic arch repair technique for preserving the lesser curvature without cardiopulmonary bypass through a left thoracotomy in neonates with coarctation of the aorta (CoA) and a hypoplastic distal aortic arch (HDAA). HDAA was defined as z-score of the aortic arch < - 2.5. Twenty-four neonates with CoA and HDAA were retrospectively studied. Patients underwent enlargement of the HDAA associated with CoA repair when their z-scores were < - 4. They were divided into 2 groups on the basis of the preoperative z-score of the distal aortic arch: group 1 (n = 14), z-score ≥ - 4; group 2 (n = 10), z-score < - 4. Twenty-two patients had intracardiac defects. Follow-up ranged from 0.9 to 20.1 years (median 11.6 years). The z-scores of the distal aortic arch were significantly smaller in group 2 than group 1 (- 5.09 ± 1.05 vs - 3.19 ± 0.36, p < 0.001). There were no hospital deaths and no hypertension. All dimensions of the aortic arch in both groups revealed significant catch-up growth (p < 0.02). All patients showed a pressure gradient ≤  5 mmHg across the aortic arch and between the arms and legs at the latest follow-up. Two patients showed an angulated arch deformity over 10 years later. This technique provided good catch-up growth and a low incidence of reobstruction and deformity of reconstructed aortic arch in both groups. These results suggest that this modification might be considered as one choice of technique for CoA and HDAA.

Short- and midterm outcomes of aortic arch reconstruction: Beating heart versus cardiac arrest

OBJECTIVES

We aimed to compare the short- and midterm results of perfusion strategies used for arch reconstruction surgery.

MATERIAL AND METHODS

One hundred and seventy-three consecutive patients who underwent aortic arch reconstruction surgery for transverse arcus hypoplasia between January 2011 and February 2020 were retrospectively analyzed. The patients were divided into two groups, as beating heart (BH) group and cardiac arrest (CA) group.

RESULTS

The CA group comprised 60 (35%) patients and the remaining 113 (65%) patients were in the BH group. The median age of the patients was 30 (interquartile range: 18-95) days. The incidences of acute renal failure (ARF) and delayed sternal closure were higher in the CA group (p = .05, <.001, respectively). Balloon angioplasty was performed in 5 (2%) patients and reoperation was performed in 11 (6%) patients due to restenosis. There were no statistically significant differences between the two groups in terms of reoperation or reintervention rates (p = .44 and .34, respectively).

CONCLUSIONS

Both strategies were associated with satisfactory midterm prevention of reintervention and reoperation. Given the lower incidence of ARF and delayed sternal closure in the postoperative period and similar midterm outcomes, we believe that the BH strategy is preferable.

Continuous cerebral and myocardial selective perfusion in neonatal aortic arch surgery

BACKGROUND

To assess the feasibility and early outcome of continuous cerebral and myocardial selective perfusion (CCMSP) during aortic arch surgery in neonates.

METHODS

We performed a single-center retrospective study between 2008 and 2019 on neonates who underwent aortic arch surgery with or without associated heart lesion repair. CCMSP with moderate hypothermia levels (28°C) was achieved using selective brachiocephalic artery and ascending aorta cannulation. Target rates of cerebral and myocardial perfusion were 25 to 35 mL/kg/min and 150 ml/m2/min. Cardiopulmonary bypass (CPB) variables and clinical outcomes were analyzed.

RESULTS

Overall, 69 neonates underwent either isolated aortic arch repair (n = 31) or aortic arch repair with ventricular septal defect (VSD) closure (n = 38). Age and weight medians were 8 [6 to 15] days and 3.4 [2.9-3.5] kg, respectively. Mean CPB and aortic clamping times were 134 ± 47 and 26 ± 5 minutes for isolated aortic arch repair, and 159 ± 47 and 75 ± 30 minutes for aortoplasty accompanied by VSD closure. Mean CCMSP time was 52 ± 21 minutes with cerebral rate of 32.6 ± 10 mL·kg^-1 ·min^-1 . Overall in hospital survival was 98.5% (68/69). Major complications were: postoperative cardiac failure requiring mechanical support followed by stroke (n = 1; 1.44%) and transient renal failure requiring dialysis (n = 2; 2.89%). Neither myocardial nor digestive complication occurred.

CONCLUSION

CCMSP is a safe and reproducible strategy for cerebral, myocardial and visceral protection in neonatal aortic arch repair, with or without VSD closure, resulting in low complication and mortality.

Changes in Cortical Thickness Are Associated With Cognitive Ability in Postoperative School-Aged Children With Tetralogy of Fallot

In children with tetralogy of Fallot (TOF), there is a risk of brain injury even if intracardiac deformities are corrected. This population follow-up study aimed to identify the correlation between cerebral morphology changes and cognition in postoperative school-aged children with TOF. Resting-state functional magnetic resonance imaging (rs-fMRI) and the Wechsler Intelligence Scale for Children–Chinese revised edition (WISC-CR) were used to assess the difference between children with TOF and healthy children (HCs). Multiple linear regression showed that the TOF group had a lower verbal intelligence quotient (VIQ, 95.000 ± 13.433, p = 0.001) than the HC group and that VIQ had significant positive correlations with the cortical thickness of both the left precuneus (p < 0.05) and the right caudal middle frontal gyrus (p < 0.05) after adjustment for preoperative SpO2, preoperative systolic blood pressure (SBP), preoperative diastolic blood pressure (DBP) and time of aortic override (AO). Our results suggested that brain injury induced by TOF would exert lasting effects on cortical and cognitive development at least to school age. This study provides direct evidence of the relationship between cortical thickness and VIQ and of the need for strengthened verbal training in school-aged TOF patients after corrective surgery.

Avoiding use of total circulatory arrest in the practice of congenital heart surgery

Deep hypothermic circulatory arrest (DHCA) technique has been an important armamentarium in the correction of congenital heart diseases. There have been many controversies and concerns associated with DHCA, particularly neurological damage. Selective ante grade cerebral perfusion (SACP) was introduced as an adjunct to DHCA with the objective of limiting the neurologic injury during aortic arch repairs. Over the past two decades, various aspects of cardiopulmonary bypass and DHCA have been studied and modified such as optimisation of flows, anti-inflammatory interventions, haematocrit, and temperature to improve neurologic outcomes. With the changes in practice of DHCA, outcomes have significantly improved but SACP intuitively appears attractive to offer better neuroprotection. The strategy of conduct of SACP is evolving and needs to be standardised for comparing outcomes. In this review we have discussed the various physiological and technical factors involved in conduct of SACP in paediatric cardiac surgery and outcomes with SACP.