Mechanisms of perioperative brain damage in children with congenital heart disease

Placental Pathology Contributes to Impaired Volumetric Brain Development in Neonates With Congenital Heart Disease

BACKGROUND

Neonates with congenital heart disease are at risk for impaired brain development in utero, predisposing children to postnatal brain injury and adverse long-term neurodevelopmental outcomes. Given the vital role of the placenta in fetal growth, we assessed the incidence of placental pathology in fetal congenital heart disease and explored its association with total and regional brain volumes, gyrification, and brain injury after birth.

METHODS AND RESULTS

Placentas from 96 term singleton pregnancies with severe fetal congenital heart disease were prospectively analyzed for macroscopic and microscopic pathology. We applied a placental pathology severity score to relate placental abnormalities to neurological outcome. Postnatal, presurgical magnetic resonance imaging was used to analyze brain volumes, gyrification, and brain injuries. Placental analyses revealed the following abnormalities: maternal vascular malperfusion lesions in 46%, nucleated red blood cells in 37%, chronic inflammatory lesions in 35%, delayed maturation in 30%, and placental weight below the 10th percentile in 28%. Severity of placental pathology was negatively correlated with cortical gray matter, deep gray matter, brainstem, cerebellar, and total brain volumes (r=-0.25 to -0.31, all P<0.05). When correcting for postmenstrual age at magnetic resonance imaging in linear regression, this association remained significant for cortical gray matter, cerebellar, and total brain volume (adjusted R2=0.25-0.47, all P<0.05).

CONCLUSIONS

Placental pathology occurs frequently in neonates with severe congenital heart disease and may contribute to impaired brain development, indicated by the association between placental pathology severity and reductions in postnatal cortical, cerebellar, and total brain volumes.

Changes in Cerebral Hemodynamics During Systemic Pulmonary Shunt and Pulmonary Artery Banding in Infants with Congenital Heart Disease

Palliative surgery is often performed in the treatment of congenital heart disease. Two representative palliative procedures are the systemic pulmonary shunt and pulmonary artery banding. Dramatic changes in cerebral hemodynamics may occur in these operations due to changes in the pulmonary-to-systemic blood flow ratio and systemic oxygenation. However, there seem to be almost no studies evaluating them. Accordingly, we evaluated cerebral perfusion by transcranial Doppler ultrasonography and cerebral oxygenation by near infrared spectroscopy during these procedures. In the post hoc analysis of a previous prospective observational study, cerebral blood flow velocities of the middle cerebral artery measured by transcranial Doppler were compared between the start and end of surgery as were the pulsatility index and resistance index. The cerebral oxygenation values were also compared between the start and end of surgery. Twenty-two infants with systemic pulmonary shunt and 20 infants with pulmonary artery banding were evaluated. There were no significant differences of the flow velocities between the start and end of surgery in either procedure. The pulsatility index significantly increased after pulmonary artery banding, which may compete with the increase in cerebral perfusion due to the increase in systemic blood flow. The cerebral oxygenation decreased in both procedures, possibly due to an increase in body temperature. Arterial oxygen saturation was almost the same before and after both procedures. Contrary to our expectation, the changes in cerebral hemodynamics in the palliative operations were small if the management of physiological indices such as arterial oxygen saturation was properly performed during the procedures.

Growth and risk of adverse neuro-developmental outcome in infants with congenital heart disease: A systematic review

AIM

Congenital heart disease (CHD) is one of the most common birth defects affecting around 1:100 infants. In this systematic review, we aimed to determine impact of growth on neurodevelopmental outcomes of infants with CHD.

METHODS

Studies that reported association of growth with developmental outcomes in infants with CHD who had surgery, were included. The search strategy was prospectively registered. Relevant studies were identified by electronic searches. The Cochrane Central Register of Controlled Trials, MEDLINE and EMBASE were searched from their earliest date to February 2022.

RESULTS

Twenty studies met inclusion criteria. Choice of growth measures, developmental assessment tools and timing of assessment varied widely precluding conduct of a meta-analysis. Seventeen studies reported on infants who had cardio-pulmonary bypass. Birth weight was reported in thirteen studies and was associated with adverse outcome in nine. Head circumference at birth and later predicted developmental outcomes in five. Impaired postnatal growth was associated with adverse developmental outcome in seven studies.

CONCLUSION

Growth in infants with congenital heart disease, specifically single ventricle physiology can predict adverse neurodevelopmental outcome. Included studies showed significant clinical heterogeneity. Uniformity should be agreed by various data registries with routine prospective collection of growth and developmental data.

Comparing near-infrared spectroscopy-measured cerebral oxygen saturation and corresponding venous oxygen saturations in children with congenital heart disease: a systematic review and meta-analysis

BACKGROUND

Near-infrared spectroscopy (NIRS) is a non-invasive approach that measures cerebral regional oxygen saturation (rScO₂). In this study, we evaluated the evidence on the validity of NIRS and the interchangeability between NIRS and common invasive approaches by exploring the correlation and consistency and comparing the mean and standard deviation between the NIRS rScO₂ and jugular bulb venous oxygen saturation (SjvO₂) as well as central venous oxygen saturation (ScvO₂) in the perioperative period of children with congenital heart disease (CHD).

METHODS

We searched electronic bibliographic databases (PubMed, The Cochrane Library and Embase) and screened the studies that met the inclusion criteria. We included cross-sectional studies of CHD pediatric patients in the perioperative period receiving both tests for NIRS rScO₂ and SjvO₂ or NIRS rScO₂ and ScvO₂. Methodological quality assessment and heterogeneity analyses were performed. We qualitatively summarized the results of Bland-Altman's analysis. Meta-regression, subgroup analyses, and sensitivity analyses were carried out to explore the causes of heterogeneity.

RESULTS

There was no significant difference in Cohen's d between rScO₂ and ScvO₂ or between rScO₂ and SjvO₂ (Cohen's d =0.06, 95% CI: -0.16 to 0.28; Cohen's d =0.03, 95% CI: -0.25 to 0.31, respectively) and notable heterogeneity existed (I²=76.0%, P<0.001; I²=73.6%, P<0.001, respectively). A positive linear correlation was present between rScO₂ and ScvO₂ or between rScO₂ and SjvO₂ (r=0.58, 95% CI: 0.54 to 0.63; r=0.60, 95% CI: 0.54 to 0.66, respectively) and the heterogeneity was not significant (I²=36.7%, P=0.065; I²=12.7%, P=0.328, respectively). In most studies, the 95% limits of agreements of Bland-Altman's analysis were large. No evidence of publication bias was observed.

CONCLUSIONS

The rScO₂ measured by NIRS reflected the SjvO₂ and ScvO₂ monitored by invasive measurements in the perioperative period of children with CHD to some extent. However, wide limits of agreements between rScO₂ and SjvO₂ as well as ScvO₂ indicated that NIRS and SjvO₂ as well as ScvO₂ are not interchangeable. Whether NIRS plays a prominent role in monitoring cerebral oxygen saturation in children with CHD needs further research.

Nomogram for Postoperative Headache in Adult Patients Undergoing Elective Cardiac Surgery

Background Postoperative headache (POH) is frequent after cardiac surgery; however, few studies on risk factors for POH exist. The aims of the current study were to explore risk factors related to POH after elective cardiac surgery and to establish a predictive system. Methods and Results Adult patients undergoing elective open-heart surgery under cardiopulmonary bypass from 2016 to 2020 in 4 cardiac centers were retrospectively included. Two thirds of the patients were randomly allocated to a training set and one third to a validation set. Predictors for POH were selected by univariate and multivariate analysis. POH developed in 3154 of the 13 440 included patients (23.5%) and the overall mortality rate was 2.3%. Eight independent risk factors for POH after elective cardiac surgery were identified, including female sex, younger age, smoking history, chronic headache history, hypertension, lower left ventricular ejection fraction, longer cardiopulmonary bypass time, and more intraoperative transfusion of red blood cells. A nomogram based on the multivariate model was constructed, with reasonable calibration and discrimination, and was well validated. Decision curve analysis revealed good clinical utility. Finally, 3 risk intervals were divided to better facilitate clinical application. Conclusions A nomogram model for POH after elective cardiac surgery was developed and validated using 8 predictors, which may have potential application value in clinical risk assessment, decision-making, and individualized treatment associated with POH.

Incidence, Risk Factors and Outcomes of Postoperative Headache After Stanford Type a Acute Aortic Dissection Surgery

Background: Postoperative headache (POH) is common in clinical practice, however, no studies about POH after Stanford type A acute aortic dissection surgery (AADS) exist. This study aims to describe the incidence, risk factors and outcomes of POH after AADS, and to construct two prediction models.

Methods: Adults who underwent AADS from 2016 to 2020 in four tertiary hospitals were enrolled. Training and validation sets were randomly assigned according to a 7:3 ratio. Risk factors were identified by univariate and multivariate logistic regression analysis. Nomograms were constructed and validated on the basis of independent predictors.

Results: POH developed in 380 of the 1,476 included patients (25.7%). Poorer outcomes were observed in patients with POH. Eight independent predictors for POH after AADS were identified when both preoperative and intraoperative variables were analyzed, including younger age, female sex, smoking history, chronic headache history, cerebrovascular disease, use of deep hypothermic circulatory arrest, more blood transfusion, and longer cardiopulmonary bypass time. White blood cell and platelet count were also identified as significant predictors when intraoperative variables were excluded from the multivariate analysis. A full nomogram and a preoperative nomogram were constructed based on these independent predictors, both demonstrating good discrimination, calibration, clinical usefulness, and were well validated. Risk stratification was performed and three risk intervals were defined based on the full nomogram and clinical practice.

Conclusions: POH was common after AADS, portending poorer outcomes. Two nomograms predicting POH were developed and validated, which may have clinical utility in risk evaluation, early prevention, and doctor-patient communication.

ZFP36 protects against oxygen-glucose deprivation/reoxygenation-induced mitochondrial fragmentation and neuronal apoptosis through inhibiting NOX4-DRP1 pathway

The imbalance of mitochondrial dynamics plays an important role in the pathogenesis of cerebral ischemia/reperfusion (I/R) injury. Zinc-finger protein 36 (ZFP36) has been documented to have neuroprotective effects, however, whether ZFP36 is involved in the regulation of neuronal survival during cerebral I/R injury remains unknown. In this study, we found that the transcriptional and translational levels of ZFP36 were increased in immortalized hippocampal HT22 neuronal cells after oxygen-glucose deprivation/reoxygenation (OGD/R) treatment. ZFP36 gene silencing exacerbated OGD/R-induced dynamin-related protein 1 (DRP1) activity, mitochondrial fragmentation, oxidative stress and neuronal apoptosis, whereas ZFP36 overexpression exhibited the opposite effects. Besides, we found that NADPH oxidase 4 (NOX4) was upregulated by OGD/R, and NOX4 inhibition remarkably attenuated OGD/R-instigated DRP1 activity, mitochondrial fragmentation and neuronal apoptosis. Further study demonstrated that ZFP36 targeted NOX4 mRNA directly by binding to the AU-rich elements (AREs) in the NOX4 3'-untranslated regions (3'-UTR) and inhibited NOX4 expression. Taken together, our data indicate that ZFP36 protects against OGD/R-induced neuronal injury by inhibiting NOX4-mediated DRP1 activation and excessive mitochondrial fission. Pharmacological targeting of ZFP36 to suppress excessive mitochondrial fission may provide new therapeutic strategies in the treatment of cerebral I/R injury.

Predictors and nomogram models for postoperative headache in patients undergoing heart valve surgery

Background

Headache is a frequent complication after cardiac surgery. However, studies on the risk factors of postoperative headache (POH) are rare. The purpose of this study was to identify independent risk factors for POH in patients undergoing heart valve surgery (HVS) and to develop and validate risk prediction models.

Methods

Consecutive patients undergoing open HVS from 2016 to 2019 were enrolled in this study. Patients were randomly assigned to training and validation sets at a 2:1 ratio. Univariate and multivariate analysis were applied to identify independent predictors for POH in the training set. A nomogram predicting POH was developed based on these factors, and was validated in the independent validation set.

Results

POH developed in 1,061 of the 3,853 patients (27.5%). The overall mortality was 2.9%, and it was significantly higher in patients with POH (4.3% versus 2.4%, P<0.001). In the training set, six independent predictors were identified by multivariate analysis, including female, smoking history, hypertension, headache history, left ventricular ejection fraction, and cardiopulmonary bypass time. The model demonstrated good discrimination in both the training (c-index: 0.811) and validation sets (c-index: 0.814), and calibration was assessed by visual inspection. A second nomogram was also constructed including only preoperative predictors, with good discrimination (c-index: 0.792) and calibration. The decision and clinical impact curves of the models showed good clinical utility.

Conclusions

We developed and validated two risk prediction models for POH in patients undergoing HVS. The models may have clinical utility in individualized risk assessment and preventive interventions.