[Efficacy of transcatheter pulmonary valve perforation in neonates with pulmonary atresia with intact ventricular septum]

Objective: To explore the efficacy and safety of transcatheter pulmonary valve perforation in the treatment of neonatal pulmonary atresia with intact ventricular septum (PA-IVS). Methods: The clinical data on surgical treatment and follow-up in 16 patients with PA-IVS who underwent transcatheter pulmonary valve perforation in Women and Children's Hospital, Qingdao University from October 2018 to October 2021 were analyzed retrospectively. The right ventricular systolic pressure and percutaneous oxygen saturation (SpO₂) were compared before and after operation. In addition, the SpO₂ and echocardiographic data at preoperative and the last follow-up were compared. Comparisons between groups were performed using paired-samples t test. Results: Among the 16 patients (10 males and 6 females) with the age at operation of 19 (14, 26) days, 12 cases underwent transcatheter pulmonary valve perforation successfully, 2 cases were transferred to surgery department for open-heart pulmonary valvulotomy, and the remaining 2 cases were transmitted to surgery department for transthoracic pulmonary valve perforation. The age at operation of the 12 patients who underwent transcatheter pulmonary valve perforation was 18 (14, 27) days, and the weight was (3.6±0.4) kg. The immediate postoperative right ventricular systolic pressure decreased significantly ((57±16) vs. (95±19) mmHg (1 mmHg=0.133 kPa), t=7.49, P<0.001), and the postoperative SpO₂ was improved effectively (0.90±0.48 vs.0.75±0.09, t=-5.61, P<0.001). The follow-up time was 22 (7, 33) months for 12 patients who underwent transcatheter pulmonary valve perforation successfully. At the last follow-up, the ratio of right to left ventricular transverse diameter was significantly higher than that before operative (0.55±0.05 vs. 0.45±0.05, t=-3.27,P=0.007). Furthermore, the Z-scores of pulmonary valvular diameter (-0.78±0.23 vs. -1.73±0.56, t=-8.52, P<0.001) and the tricuspid valvular diameter (-0.52±0.12 vs. -1.46±0.38, t=-10.40, P<0.001) were all significantly higher than preoperative data. At last, all the patients achieved biventricular circulation without death or major complications. Conclusion: Transcatheter pulmonary valve perforation is a safe and effective therapy for neonatal PA-IVS, and its curative effect has been confirmed by the medium follow-up data.

[Application of arterial duct stent in ductus-dependent hypoplastic right heart syndrome]

Objective: To summarize the experience of arterial duct (AD) stenting in children with ductus-dependent hypoplastic right heart syndrome (HRHS). Methods: Seven children including 4 cases of pulmonary atresia with intact ventricular septum (PA-IVS) with HRHS and 3 cases of critical pulmonary stenosis (CPS)-IVS with HRHS underwent AD stenting in Qingdao Women and Children's Hospital between January 2012 and January 2019. During the same period, 9 patients of PA-IVS with HRHS received Blalock Taussig (B-T) shunt. Two groups of children on the operation time, hospital stay time, intensive care time and mortality were compared.T test or Mann-Whitney U test was used for comparison between the two groups. Results: There was no significant difference in the age (18 (7-100) vs. 17 (1-142) d, U=31.000, P>0.05) and weight ((3.8±1.1) vs. (3.7±1.3) kg, t=0.272, P>0.05) between the AD stenting group and the B-T group.The operation time ((108±7) vs. (160±49) min, t=-4.304), intensive care time ((3.4±1.0) vs. (6.3±4.5) d, t=-8.692) and total hospitalization time ((10.3±1.0) vs. (26.3±1.0) d, t=-7.822) in the AD stenting group were differed significantly compared with the B-T group (all P<0.05). The transcutaneous oxygen saturation improved significantly (0.723±0.125 vs. 0.926±0.005, t=-6.044, P<0.05) after AD stenting. The diameter of AD stent ranged from 3.5 to 4.0 mm, and the length of AD stent was 16-21 mm. There were no complications such as vascular injury, acute thrombus, catheter spasm and death in the AD stenting group. The mortality of children in the B-T group was 3 in 9 cases. Three cases in the AD stenting group received pulmonary valvulotomy and bilateral Glenn operation at 6, 9 and 9 months after AD stenting, respectively. Conclusions: AD stenting is a feasible, effective, safe and minimally invasive procedure for children with ductus-dependent HRHS. It can even be used as an alternative to B-T shunt.

Sustained Abdominal Aorta Compression Elevates Coronary Perfusion Pressure after Asphyxia-Induced Cardiac Arrest in a Rabbit Model

Objective

To investigate whether sustained abdominal aorta compression (SAAC) can improve coronary perfusion pressure (CPP) during cardiopulmonary resuscitation (CPR) and improve resuscitation outcomes without causing liver laceration.

Design and Setting

Animal study.

Methods

Cardiac arrest was induced by asphyxia in 28 New Zealand rabbits and maintained for 2 minutes before resuscitation. Animals were resuscitated using either standard CPR (STD-CPR group) or standard CPR and SAAC (SAAC-CPR group). Restoration of spontaneous circulation (ROSC), restoration of spontaneous breathing (ROSB) and cerebral performance category score were determined. CPP, mean arterial pressure (MAP) and ROSC were compared in the two groups.

Results

MAP and CPP in the SAAC-CPR group were significantly higher than in the STD-CPR group. However, MAP and blood gas results showed no significant difference between the two groups during ROSC. ROSC was achieved in seven of fourteen animals in the STD-CPR group and in eleven of fourteen animals in the SAAC-CPR group. Five animals in the STD-CPR group and nine in the SAAC-CPR group survived 24 hours after ROSC. No liver injury occurred in the two groups.

Conclusions

SAAC-CPR produces an increased CPP and MAP than traditional CPR and it does not lead to liver laceration/injury.

Arg-Gly-Asp-Ser-selective adhesion and the stabilization of long-term potentiation: pharmacological studies and the characterization of a candidate matrix receptor

Peptides known to block the extracellular interactions of adhesion receptors belonging to a subclass of the integrin family were tested for their effects on the stabilization of long-term potentiation (LTP) in hippocampal slices. Theta burst stimulation delivered after infusions of Gly-Ala-Val-Ser-Thr-Ala (GAVSTA) resulted in a potentiation effect that decayed steadily over a period of 40 min; LTP elicited in the presence of inactive control peptides remained stable over this time period. GAVSTA had no detectible influence on baseline responses, induction processes, or the initial degree of potentiation. Infusions of integrin antagonists after application of theta bursts also resulted in the occurrence of a decremental form of LTP. Affinity chromatography was then used in an effort to identify targets of the structurally dissimilar integrin blockers that disrupt LTP stabilization. Both integrin antagonists Gly-Arg-Gly-Asp-Ser-Pro and GAVSTA eluted a major species of 55 kDa (synaptegrin-1) from GRGDSP-affinity columns that had been loaded with solubilized synaptic membranes; lesser concentrations of three polypeptides of approximately 20, 27, and 30 kDa were also collected. Synaptegrin-1 was labeled by antibodies to the RGDS-binding integrin alpha5beta1. In addition, the synaptegrin, as well as the 27 kDa, protein was found to copurify with pre- and postsynaptic markers during the isolation of forebrain synaptosomes. These results indicate that a matrix recognition event occurring several minutes after induction of LTP is a necessary step in the stabilization of potentiated synapses; they also identify an integrin-like matrix receptor of 55 kDa that may contribute to this event.

The induction of homo- vs. heterosynaptic LTD in area CA1 of hippocampal slices from adult rats

The induction of long-term depression (LTD) was investigated in area CA1 of hippocampal slices from adult rats. To produce LTD, prolonged low-frequency stimulation (LFS, 900 stimuli at 1 Hz) was delivered to one of two independent Schaffer-collateral/commissural projections, while the second input served as a control to monitor heterosynaptic effects. The depression was calculated as percent decrease in the slope of the dendritic field EPSP relative to baseline values, and LTD was considered established if the response decrement was at least 15% in magnitude and stable for 30-60 min. By delivering LFS in conditions of different relative baseline response magnitudes, it was revealed that the intensity of afferent low-frequency activity has a significant impact on the induction frequency, magnitude and input-specificity of the depression: the rate of LTD occurrence and the effect of LFS on the absolute response decrement increased successively as the stimulation strength was raised, but the impact of LFS on the relative LTD magnitude decreased at higher stimulation intensities; the depression was specific to the stimulated input (homosynaptic LTD) when baseline responses were spike-free, but spread to the pathway which was silent during LFS (heterosynaptic LTD) in experiments conducted above spiking threshold. The results indicate that in the adult rat (i) the induction of input-specific LTD is dependent on the level of synaptic activation during LFS, and (ii) LTD can easily be obtained in strongly stimulated pathways but may be the result of a generalized decrease in the postsynaptic response.