1.Optimization of flow rate and orientation of outflow graft at implantation for patients with left ventricular assist device.
Yongyi WANG ; Li SHI ; Shijun HU ; Xiao TAN ; Tianli ZHAO
Journal of Central South University(Medical Sciences) 2025;50(3):457-468
OBJECTIVES:
A ventricular assist device (VAD) is an electromechanical device used to assist cardiac blood circulation, which can be employed for the treatment of end-stage heart failure and is most commonly placed in the left ventricle. Despite enhancing perfusion performance, the implantation of left ventricular assist device (LVAD) transforms the local intraventricular flow and thus may increase the risk of thrombogenesis. This study aims to investigate fluid-particle interactions and thromboembolic risk under different LVAD configurations using three-dimensional (3D) reconstruction models, focusing on the effects of outflow tract orientation and blood flow rates.
METHODS:
A patient-specific end-diastolic 3D reconstruction model was initially constructed in stereo lithography (STL) format using Mimics software based on CT images. Transient numerical simulations were performed to analyze fluid-particle interactions and thromboembolic risks for LVAD with varying outflow tract orientations under 2 flow rates (4 L/min and 5 L/min), using particles of uniform size (2 mm), and a blood flow rate optimization protocol was implemented for this patient.
RESULTS:
When the LVAD flow rate was 5 L/min, helicity and flow stagnation of the blood flow increased the particle residence time (RT) and the risk of thrombogenesis of the aortic root. The percentage of particles traveling toward the brachiocephalic trunk was up to 20.33%. When the LVAD flow rate was 4 L/min, blood turbulence in the aorta was reduced, the RT of blood particles was shortened, and then the percentage of particles traveling toward the brachiocephalic trunk decreased to 10.54%. When the LVAD blood flow rate was 5 L/min and the direction of the outflow pipe was optimal, the RT of blood particles was shortened, and then the percentage of particles traveling toward the brachiocephalic trunk decreased to 11.22%. A 18-month follow-up observation of the patient revealed that the LVAD was in good working order and the patient had no complications related to the implantation of LVAD.
CONCLUSIONS
Implantation of LVAD results in a higher risk of cerebral infarction; When implanting LVAD with the same outflow tract direction, optimizing flow velocity and outflow tract can reduce the risk of cerebral infarction occurrence.
Heart-Assist Devices/adverse effects*
;
Humans
;
Heart Failure/physiopathology*
;
Blood Flow Velocity
;
Thromboembolism/prevention & control*
;
Models, Cardiovascular
;
Heart Ventricles/physiopathology*
;
Imaging, Three-Dimensional
2.An attention-guided network for bilateral ventricular segmentation in pediatric echocardiography.
Jun PANG ; Yongxiong WANG ; Lijun CHEN ; Jiapeng ZHANG ; Jinlong LIU ; Gang PEI
Journal of Biomedical Engineering 2023;40(5):928-937
Accurate segmentation of pediatric echocardiograms is a challenging task, because significant heart-size changes with age and faster heart rate lead to more blurred boundaries on cardiac ultrasound images compared with adults. To address these problems, a dual decoder network model combining channel attention and scale attention is proposed in this paper. Firstly, an attention-guided decoder with deep supervision strategy is used to obtain attention maps for the ventricular regions. Then, the generated ventricular attention is fed back to multiple layers of the network through skip connections to adjust the feature weights generated by the encoder and highlight the left and right ventricular areas. Finally, a scale attention module and a channel attention module are utilized to enhance the edge features of the left and right ventricles. The experimental results demonstrate that the proposed method in this paper achieves an average Dice coefficient of 90.63% in acquired bilateral ventricular segmentation dataset, which is better than some conventional and state-of-the-art methods in the field of medical image segmentation. More importantly, the method has a more accurate effect in segmenting the edge of the ventricle. The results of this paper can provide a new solution for pediatric echocardiographic bilateral ventricular segmentation and subsequent auxiliary diagnosis of congenital heart disease.
Adult
;
Humans
;
Child
;
Heart Ventricles/diagnostic imaging*
;
Echocardiography
;
Image Processing, Computer-Assisted
3.Characteristics of the left heart structure and function in 86 term neonates with intrauterine growth restriction.
Mo-Qi LI ; Ying-Xue DING ; Hong CUI ; Li-Na JIANG ; Zi-Wei WANG ; Yan-Ru LAI ; Bai-Hong LI ; Wen-Hong DING
Chinese Journal of Contemporary Pediatrics 2023;25(10):1016-1021
OBJECTIVES:
To study the left heart structure and functional characteristics of term neonates with intrauterine growth restriction (IUGR).
METHODS:
This study included 86 term neonates with IUGR admitted to the Neonatal Ward of Beijing Friendship Hospital, Capital Medical University from January 2019 to January 2022 as the IUGR group, as well as randomly selected 86 term neonates without IUGR born during the same period as the non-IUGR group. The clinical data and echocardiographic data were compared between the two groups.
RESULTS:
The analysis of left heart structure and function showed that compared with the non-IUGR group, the IUGR group had significantly lower left ventricular mass, left ventricular end-diastolic diameter, left ventricular end-systolic diameter, left atrial diameter, end-diastolic interventricular septal thickness, left ventricular posterior wall thickness, left ventricular end-diastolic volume, left ventricular end-systolic volume, and stroke volume (P<0.05) and significantly higher ratio of end-diastolic interventricular septal thickness to left ventricular posterior wall thickness, proportion of neonates with a mitral peak E/A ratio of ≥1, and cardiac index (P<0.05). The Spearman correlation analysis suggested that stroke volume was positively correlated with birth weight and body surface area (rs=0.241 and 0.241 respectively; P<0.05) and that the ratio of end-diastolic interventricular septal thickness to left ventricular posterior wall thickness was negatively correlated with birth weight and body surface area (rs=-0.229 and -0.225 respectively; P<0.05).
CONCLUSIONS
The left ventricular systolic function of neonates with IUGR is not significantly different from that of neonates without IUGR. However, the ventricular septum is thicker in neonates with IUGR. This change is negatively correlated with birth weight and body surface area. The left ventricular diastolic function may be impaired in neonates with IUGR.
Humans
;
Infant, Newborn
;
Birth Weight
;
Echocardiography
;
Fetal Growth Retardation
;
Heart
;
Heart Ventricles/diagnostic imaging*
;
Ventricular Function, Left
4.Progress in the application of patch materials in cardiovascular surgery.
Rubing SHAO ; Jiehua LI ; Lunchang WANG ; Xin LI ; Chang SHU
Journal of Central South University(Medical Sciences) 2023;48(2):285-293
The cardiovascular patch, served as artificial graft materials to replace heart or vascular tissue defect, is still playing a key role in cardiovascular surgeries. The defects of traditional cardiovascular patch materials may determine its unsatisfactory long-term effect or fatal complications after surgery. Recent studies on many new materials (such as tissue engineered materials, three-dimensional printed materials, etc) are being developed. Patch materials have been widely used in clinical procedures of cardiovascular surgeries such as angioplasty, cardiac atrioventricular wall or atrioventricular septum repair, and valve replacement. The clinical demand for better cardiovascular patch materials is still urgent. However, the cardiovascular patch materials need to adapt to normal coagulation mechanism and durability, promote short-term endothelialization after surgery, and inhibit long-term postoperative intimal hyperplasia, its research and development process is relatively complicated. Understanding the characteristics of various cardiovascular patch materials and their application in cardiovascular surgeries is important for the selection of new clinical surgical materials and the development of cardiovascular patch materials.
Cardiac Surgical Procedures/methods*
;
Tissue Engineering
;
Heart Ventricles
;
Heart Atria
;
Treatment Outcome
5.Comparison of immediate changes of repolarization parameters after left bundle branch area pacing and traditional biventricular pacing in heart failure patients.
Yao LI ; Wenzhao LU ; Qingyun HU ; Chendi CHENG ; Jinxuan LIN ; Yu'an ZHOU ; Ruohan CHEN ; Yan DAI ; Keping CHEN ; Shu ZHANG
Chinese Medical Journal 2023;136(7):868-870

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