Metal-Free Perovskite Ferroelectrics with the Most Equivalent Polarization Axes.

Ferroelectricity in metal-free perovskites (MFPs) has emerged as an academic hotspot for their lightweight, eco-friendly processability, flexibility, and degradability, with considerable progress including large spontaneous polarization, high Curie temperature, large piezoelectric response, and tailoring coercive field. However, their equivalent polarization axes as a key indicator are far from enough, although multiaxial ferroelectrics are highly preferred for performance output and application flexibility that profit from as many equivalent polarization directions as possible with easier reorientation. Here, by implementing the synergistic overlap of regulating anionic geometries (from spherical I- to octahedral [PF6]- and to tetrahedral [ClO4]- or [BF4]-) and cationic asymmetric modification, we successfully designed multiaxial MFP ferroelectrics CMDABCO-NH4-X3 (CMDABCO = N-chloromethyl-N'-diazabicyclo[2.2.2]octonium; X = [ClO4]- or [BF4]-) with the lowest P1 symmetry. More impressively, systemic characterizations indicate that they possess 24 equivalent polarization axes (Aizu notations of 432F1 and m3̅mF1, respectively)─the maximum number achievable for ferroelectrics. Benefiting from the multiaxial feature, CMDABCO-NH4-[ClO4]3 has been demonstrated to have excellent piezoelectric sensing performance in its polycrystalline sample and prepared composite device. Our study provides a feasible strategy for designing multiaxial MFP ferroelectrics and highlights their great promise for use in microelectromechanical, sensing, and body-compatible devices.

Organic-Inorganic Rare-Earth Double Perovskite Ferroelectric with Large Piezoelectric Response and Ferroelasticity for Flexible Composite Energy Harvesters.

Hybrid organic-inorganic perovskite (HOIP) ferroelectric materials have great potential for developing self-powered electronic transducers owing to their impressive piezoelectric performance, structural tunability and low processing temperatures. Nevertheless, their inherent brittle and low elastic moduli limit their application in electromechanical conversion. Integration of HOIP ferroelectrics and soft polymers is a promising solution. In this work, a hybrid organic-inorganic rare-earth double perovskite ferroelectric, [RM3HQ]2RbPr(NO3)6 (RM3HQ = (R)-N-methyl-3-hydroxylquinuclidinium) is presented, which possesses multiaxial nature, ferroelasticity and satisfactory piezoelectric properties, including piezoelectric charge coefficient (d33) of 102.3 pC N-1 and piezoelectric voltage coefficient (g33) of 680 × 10-3 V m N-1. The piezoelectric generators (PEG) based on composite films of [RM3HQ]2RbPr(NO3)6@polyurethane (PU) can generate an open-circuit voltage (Voc) of 30 V and short-circuit current (Isc) of 18 µA, representing one of the state-of-the-art PEGs to date. This work has promoted the exploration of new HOIP ferroelectrics and their development of applications in electromechanical conversion devices.

Personalized Three-Dimensional Printing and Echoguided Procedure Facilitate Single Device Closure for Multiple Atrial Septal Defects.

BACKGROUND: To evaluate the feasibility of using a single device to close multiple atrial septal defects (ASDs) under the guidance of transthoracic echocardiography (TTE) and with the aid of three-dimensional (3D) printing models. METHODS: Sixty-two patients with multiple ASDs were retrospectively analyzed. Thirty of these patients underwent TTE-guided closure (3D printing and TTE group) after a simulation of occlusion in 3D printing models. The remaining 32 patients underwent ASD closure under fluoroscopic guidance (conventional group). Closure status was assessed immediately and at 6 months after device closure. RESULTS: Successful transcatheter closure with a single device was achieved in 26 patients in the 3D printing and TTE group and 27 patients in the conventional group. Gender, age [18.8 ± 15.9 (3-51) years in the 3D printing and TTE group; 14.0 ± 11.6 (3-50) years in the conventional group], mean maximum distance between defects, prevalence of 3 atrial defects and large defect distance (defined as distance ≥7 mm), and occluder size used were similarly distributed between groups. However, the 3D printing and TTE group had lower frequency of occluder replacement (3.8% vs 59.3%, p < 0.0001), prevalence of mild residual shunts (defined as <5 mm) immediately (19.2% vs 44.4%, p < 0.05) and at 6 months (7.7% vs 29.6%, p < 0.05) after the procedure, and cost (32960.8 ± 2018.7 CNY vs 41019.9 ± 13758.2 CNY, p < 0.01). CONCLUSION: The combination of the 3D printing technology and ultrasound-guided interventional procedure provides a reliable new therapeutic approach for multiple ASDs, especially for challenging cases with large defect distance.

Transthoracic Echocardiography-Guided Percutaneous Patent Ductus Arteriosus Occlusion: A New Strategy for Interventional Treatment.

INTRODUCTION: Percutaneous patent ductus arteriosus (PDA) occlusion has become the preferred therapeutic option, which uses fluoroscopy as the guidance. To reduce the x-ray exposure, PDA occlusion using the Amplatzer Duct Occluder II (ADO II) under guidance of transthoracic echocardiography only was conducted. This single center study aims to access the safety and efficiency of this new strategy. METHODS AND RESULTS: From June 2013 to May 2015, 63 consecutive PDA patients underwent transthoracic echocardiography-guided PDA occlusion through the femoral artery. Outpatient follow-up was conducted at 1, 3, and 6 months, and yearly. Sixty-two patients successfully underwent echocardiography-guided percutaneous PDA occlusion. One patient was converted to minimally invasive transthoracic occlusion due to failure of delivery sheath passage through tortuous PDA. Mean procedure duration was 24.3 ± 7.0 minutes; ADO II diameter averaged 4.6 ± 0.9 mm; 8 cases showed traces of residual shunt immediately after operation which resolved after 24 hours; and mean hospital stay was 3.4 ± 0.5 days. There was no occluder migration, hemolysis, pericardial effusion, pulmonary branch or aortic stenosis at mean 13.5 ± 4.8 months follow-up. CONCLUSIONS: This study demonstrated that percutaneous PDA occlusion can be successfully performed under guidance of transthoracic echocardiography only and appears safe and effective while avoiding radiation and contrast agent use.

Percutaneous Closure of Atrial Septal Defects Under Transthoracic Echocardiography Guidance Without Fluoroscopy or Intubation in Children.

OBJECTIVE: Demonstrate the benefits of percutaneous atrial septal defect (ASD) closure under guidance of transthoracic echocardiography (TTE) without fluoroscopy. METHODS: From February 2013 to April 2014, 127 consecutive patients with an isolated type II ASD were recruited to undergo percutaneous closure under either TTE (n = 60, TTE group) or TEE (n = 67, TEE group) guidance. The TTE group received local anesthesia or sedation with propofol, and the TEE group received general anesthesia with endotracheal intubation. Follow-up examinations were performed for both groups at 1 month, 3 months, 6 months, and 1 year after discharge and annually thereafter. RESULTS: The TTE group had a significantly shorter procedure time and respirator ventilation duration than the TEE group. The dose of propofol required, the cost, and the pharyngeal complication rate were significantly lower in the TTE group than in the TEE group. The median follow-up of 11.6 months was uneventful in all patients. CONCLUSIONS: Percutaneous ASD closure with TTE guidance as the only imaging tool avoids fluoroscopy, endotracheal intubation, and probe insertion and is associated with a satisfactory procedural success rate and lower costs. This procedure is a safe and reliable treatment for ASD.

[Safety and efficacy of percutaneous transcatheter closure of atrial septal defect under transesophageal echocardiography guidance in children].

OBJECTIVE: To assess the safety and effectiveness of percutaneous transcatheter closure of atrial septal defect (ASD) under transesophageal echocardiography (TEE) guidance in children. METHODS: The study included 20 cases of patients with ASD. The patients were (4.2 ± 1.2) years old and the mean body weights were (18.2 ± 4.2) kg. The diameter of ASD before closure was (13.4 ± 3.3) mm . All procedures were guided under TEE. Procedure success was evaluated by TEE immediately after procedure. RESULTS: Closure devices were successfully implanted in all 20 patients under TEE guidance. The diameter of closure devices was 14-26 mm. There were no procedure related complications. The ventilation time was (2.9 ± 0.8)h and the hospitalization time was (3.2 ± 0.7) days. CONCLUSION: TEE guided percutaneous transcatheter closure is safe and effective for patients with ASD and avoids the radiation damages.

Propensity-matched comparison of balloon-expandable and self-expanding valves for transcatheter aortic valve replacement in a Chinese population.

Background: Balloon-expandable valves (BEV) and self-expanding valves (SEV) for transcatheter aortic valve replacement (TAVR) have shown promising results in Western populations. Herein, we comparatively evaluated their hemodynamics and early clinical outcomes in a Chinese population. Methods: One hundred seventy-eight patients with symptomatic aortic stenosis who had undergone transfemoral TAVR using SEV (n=153; Venus-A, 97; VitaFlow, 56) or BEV (n=25; Sapien3) from September 2020 to April 2021 were retrospectively enrolled, and 25 pairs were propensity-score matched for 10 baseline variables. The primary study outcomes were aortic valve hemodynamics and postoperative complications at discharge and 3-month follow-up. Results: TAVR was successful in all patients. Compared with SEV group, the BEV group had similarly distributed baseline characteristics, procedural time, hospital stay, new pacemaker implantation, and paravalvular regurgitation grade. We also observed that the BEV group had lower rates of balloon pre-dilation (60% vs. 92%, P=0.018), post-dilation (0 vs. 20%, P=0.050) and second valve implantation (0 vs. 24%, P=0.022); higher mean transaortic gradient (14.3±6.1 vs. 10.8±4.9, P=0.030) and proportion of patients with elevated gradients (20% vs. 0, P=0.050) at discharge; and similar rehospitalization, mean transaortic gradient, new pacemaker implantation, and paravalvular regurgitation grade than the SEV group at the 3-month follow-up. There were no deaths in either group. However, the proportion of patients with elevated gradients in SEV group was higher at 3 months than before discharge (24% vs. 0, P=0.022). Conclusions: BEV and SEV for transfemoral TAVR appear comparably safe and effective, with high device success and favorable 3-month clinical outcomes. However, the transaortic gradient and new pacemaker implantation in the SEV group increased during follow-up, warranting larger studies with longer-term follow-up.

[Endogenous formaldehyde and cardiovascular diseases].

Endogenous formaldehyde is produced via semicarbazide-sensitive amine oxidase-catalyzed deamination of methylamine. It widely exists in a variety of tissues and cells in animals. It has been confirmed that endogenous formaldehyde is involved in the neural degeneration, immune disease and tumor process. Adipocytes, vascular endothelial cells and smooth muscle cells are rich in enzyme to generate formaldehyde-semicarbazide-sensitive amine oxidase (SSAO). Formaldehyde may cause cytotoxicity, which induces vascular endothelial injury and mediates multiple factor-induced pathogenic process of vascular injury. It plays important role in atherosclerosis, diabetes mellitus and diabetic complication.

A novel double-balloon catheter for percutaneous balloon pulmonary valvuloplasty under echocardiographic guidance only.

BACKGROUND: Percutaneous balloon pulmonary valvuloplasty (PBPV) is the procedure of choice for uncomplicated severe or symptomatic pulmonary stenosis. Echocardiography (echo)-guided PBPV can completely avoid the use of radiation and contrast agents compared to fluoroscopy-guided PBPV. Although we have confirmed that echo-guided PBPV is feasible in humans, the poor visibility of the traditional catheter under echo greatly limits the promotion of this new technology. METHODS: We produced a novel double-balloon catheter to make the catheter easy to be detected by echo through adding a guiding balloon at the distal end of the catheter. Echo-guided PBPV was performed on thirty healthy swine using either a novel catheter or a traditional catheter to evaluate the feasibility and safety of the novel double-balloon catheter. The feasibility was evaluated by the success rate of balloon inflation at the pulmonary valve annulus and the operating time. The safety was evaluated by the frequency of balloon slippage and the incidence of complications. RESULTS: There were no significant between-group differences in terms of weight and the ratio of balloon diameter to pulmonary annulus diameter. The success rate was 93.3% and 60% in the novel and traditional groups, respectively. The novel group had significantly (p<0.05) lower mean procedure time (6.33±6.86min vs 24.8±9.79min) and lower frequency of balloon slippage (0.07±0.26 vs 0.53±0.52), arrhythmia (0.07±0.26 vs 0.47±0.52), and tricuspid regurgitation (6.7% vs 40%) than the traditional group. No myocardial hematoma or pericardial tamponade occurred in the novel catheter group. CONCLUSION: Although further studies and improvements are required, the study results indicate that the novel double-balloon catheter for echo-guided PBPV is feasible and safe.

Multicenter Comparison of Percutaneous and Surgical Pulmonary Valve Replacement in Large RVOT.

BACKGROUND: A percutaneous approach for pulmonary valve replacement (PVR) is a feasible alternative to surgical PVR in selected patients with severe pulmonary regurgitation after repair of tetralogy of Fallot. However, large right ventricular outflow tract (diameter ≥ 25 mm) remains challenging. METHODS: This retrospective multicenter study enrolled consecutive patients with large right ventricular outflow tract who underwent percutaneous PVR (Venus P-valve, Venus MedTech Inc, Hangzhou, China) (n = 35) or surgical PVR (homograft valve; n = 30) between May 2014 and April 2017. Patients were followed up at 1, 3, 6, and 12 months, and yearly thereafter. Main study outcomes were pulmonary valve function and right ventricular function at discharge and midterm follow-up. RESULTS: PVR was successful in all patients. Percutaneous compared with surgical PVR group had: similarly distributed baseline characteristics; shorter hospitalization, intensive care unit stay, and endotracheal intubation duration; lower cost; lower pulmonary valve gradient before discharge; lower pulmonary valve regurgitant grade (mean difference, -0.63; 95% CI -1.11 to -0.20, P = .022), pulmonary valve gradient (mean difference, -5.7 mm Hg; 95% CI -9.4 to -2.2 mm Hg, P = .005), and right ventricular end-diastolic volume index (mean difference, -9.5 mL/m2; 95% CI -16.9 to -3.1 mL/m2, P = .022); and greater right ventricular ejection fraction (mean difference, 5.4%; 95% CI 2.4%-8.3%, P = .002) at median 36 months follow-up, without deaths in either group. CONCLUSIONS: Percutaneous PVR using Venus P-valve appeared to be a safe, efficacious and minimally invasive alternative to surgical PVR in selected patients with large right ventricular outflow tract yielding better right ventricular and pulmonary valve function at midterm follow-up.