Atrial septal defect (ASD) is a congenital heart disease that causes blood communication between the left and right ventricles due to partial atrial septal tissue defects, accounting for about 13% of all heart malformations. Secondary ASD is the most common type of ASD and can generally be treated with minimally invasive closure. At present, the commonly used minimally invasive methods in clinical practice mainly include X-ray-guided percutaneous occlusion, transesophageal ultrasound-guided transthoracic occlusion and ultrasound-guided percutaneous occlusion. This review focuses on the basic research process of occluder materials, and advantages and disadvantages of three different surgical methods.
A solid-liquid two-phase finite element model of articular cartilage and a microscopic finite element model of chondrocytes were established using the finite element software COMSOL in this study. The purpose of the study is to investigate the mechanics environment and the liquid flow field of the host cartilage chondrocytes in each layer by multi-scale method, under physiological load, with the different elastic modulus of artificial cartilage to repair cartilage defect. The simulation results showed that the uniform elastic modulus of artificial cartilage had different influences on the microenvironment of different layer chondrocytes. With the increase of the elastic modulus of artificial cartilage, the stress of the shallow surface layer and the intermediate layer chondrocytes increased and the stress of deep layer chondrocytes decreased. The flow field direction of the middle layer and the bottom layer of cartilage can also be changed by artificial cartilage implantation, as well as the ways of nourishment supply of the middle layer and underlying chondrocytes change. A barrier to underlying chondrocytes nutrition supply may be caused by this, thus resulting in the uncertainty of the repair results. With cross-scale finite element model simulation analysis of chondrocytes, we can quantitatively evaluate the mechanical environment of chondrocytes in each layer of the host cartilage. It is helpful to assess the clinical effect of cartilage defect reparation more accurately.
Objective To evaluate the safety, efficacy, and mid-term clinical outcomes of the Salus? transthoracic interventional self-expanding pulmonary valve stent system in the treatment of patients with pulmonary regurgitation. Methods The clinical data of patients who underwent transthoracic pulmonary valve stent implantation at Huazhong Fuwai Hospital between September 2021 and August 2023 were retrospectively analyzed. All procedures were performed via a small subxiphoid incision, with the delivery access established through the acute margin of the right ventricle. Results A total of 10 patients with moderate-to-severe pulmonary regurgitation were enrolled, comprising 8 males and 2 females. The mean age was (21.32±11.48) years, and the mean body weight was (59.16±19.92) kg. The preoperative median right ventricular end-diastolic volume index (RVEDVI) and right ventricular end-systolic volume index were 152.95 (121.97, 174.25) mL/m2 and 86.74 (70.29, 117.73) mL/m2, respectively. All patients successfully underwent transthoracic self-expanding pulmonary valve stent implantation. Intraoperative stent displacement occurred in 1 patient, who was successfully managed by extending the incision, performing an incision on the right ventricular outflow tract, and manually fixing the valve. In a patient with heart failure and concomitant renal insufficiency requiring intermittent dialysis, renal function did not significantly improve after surgery, who subsequently demonstrated improvement following the initiation of continuous renal replacement therapy and continued to require maintenance dialysis at the time of the last follow-up. The mean follow-up duration was (33.40±7.93) months. During the follow-up period, there were no deaths or recurrence of severe pulmonary regurgitation, while frequent premature ventricular contractions occurred in 1 patient. Compared to the baseline, the RVEDVI significantly decreased to 106.49 (91.32, 121.69) mL/m2 at 1 year postoperatively (P=0.008). At the last follow-up, the left ventricular end-diastolic diameter significantly increased, the right ventricular longitudinal diameter significantly decreased, the severity of pulmonary regurgitation markedly improved, and the QRS duration significantly shortened compared to the preoperative baseline (all P<0.05). ConclusionTransthoracic implantation of the Salus? pulmonary valve stent system is safe and effective in treating patients with pulmonary regurgitation, demonstrating satisfactory mid-term outcomes. It may serve as a potential complementary alternative to percutaneous pulmonary valve implantation.
