Caili Li^{1, §}, Christopher Baird², Jing Yao³, Chun Yang⁴, Liang Wang⁵, Han Yu⁵, Tal Geva⁶, Dalin Tang^{5*, 7, §}

CMES-Computer Modeling in Engineering & Sciences, Vol.119, No.1, pp. 227-244, 2019, DOI:10.32604/cmes.2019.06036

Abstract Pulmonary valve stenosis (PVS) is one common right ventricular outflow tract obstruction problem in patients with tetralogy of Fallot (TOF). Congenital bicuspid pulmonary valve (BPV) is a condition of valvular stenosis, and the occurrence of congenital BPV is often associated with TOF. Dynamic computational models of normal pulmonary root (PR) with tri-leaflet and PR with BPV in patients with TOF were developed to investigate the effect of geometric structure of BPV on valve stress and strain distributions. The pulmonary root geometry included valvular leaflets, sinuses, interleaflet triangles and annulus. Mechanical properties of pulmonary valve leaflet were obtained from biaxial testing… More >

Sara Salehyar^{1, †}, Nickolas Forsch^1,†,*, Kathleen Gilbert^2,3, Alistair A. Young^3,4, James C. Perry⁵, Sanjeet Hegde⁵, Jeffrey H. Omens^1,6, Andrew D. McCulloch^1,6

Molecular & Cellular Biomechanics, Vol.16, No.3, pp. 179-183, 2019, DOI:10.32604/mcb.2019.07384

Abstract Tetralogy of Fallot (TOF) is the most common form of cyanotic congenital heart disease. Infants diagnosed with TOF require surgical interventions to survive into adulthood. However, as a result of postoperative structural malformations and long-term ventricular remodeling, further interventions are often required later in life. To help identify those at risk of disease progression, serial cardiac magnetic resonance (CMR) imaging is used to monitor these patients. However, most of the detailed information on cardiac shape and biomechanics contained in these large four-dimensional (4D) data sets goes unused in clinical practice for lack of efficient and comprehensive quantitative analysis tools. While… More >

Zhedian Zhou¹, Tal Geva², Rahul H. Rathod², Alexander Tang², Chun Yang³, Kristen L. Billiar⁴, Dalin Tang^1,*,3, Pedro del Nido⁵

Molecular & Cellular Biomechanics, Vol.15, No.2, pp. 99-115, 2018, DOI: 10.3970/mcb.2018.00558

Abstract Patients with repaired Tetralogy of Fallot (ToF), a congenital heart defect which includes a ventricular septal defect and severe right ventricular outflow obstruction, account for the majority of cases with late onset right ventricle (RV) failure. The current surgical approach, which includes pulmonary valve replacement/insertion (PVR), has yielded mixed results. A computational parametric study using 7 patient-specific RV/LV models based on cardiac magnetic resonance (CMR) data as "virtual surgery" was performed to investigate the impact of patch size, RV remodeling and tissue regeneration in PVR surgery design on RV cardiac functions. Two patch sizes, three degrees of scar trimming (RV… More >

Dalin Tang^1,*,2, Heng Zuo^2,*, Chun Yang², Zheyang Wu², Xueying Huang³, Rahul H. Rathod⁴, Alexander Tang⁴, Kristen L. Billiar⁵, Tal Geva⁴

Molecular & Cellular Biomechanics, Vol.14, No.3, pp. 137-151, 2017, DOI:10.3970/mcb.2017.014.137

Abstract Patients with repaired tetralogy of Fallot (TOF) account for the majority of cases with late onset right ventricle failure. Comparing TOF patients with healthy people may provide information to address this challenge. Cardiac magnetic resonance (CMR) data were obtained from 16 TOF patients (patient group, PG) and 6 healthy volunteers (healthy group, HG). At begin-of-ejection, better patient group (n=5, BPG) stress was very close to HG stress (54.7±38.4 kPa vs. 51.2±55.7 kPa, p=0.6889) while worse patient group (n=11, WPG) stress was 84% higher than HG stress (p=0.0418). Stress may be used as an indicator to differentiate BPG patients from WPG… More >

Ashish Das^∗, William M. Gottliebson^†,‡, Madhura Karve^∗, Rupak Banerjee^∗,§,¶

Molecular & Cellular Biomechanics, Vol.8, No.1, pp. 21-42, 2011, DOI:10.3970/mcb.2011.008.021

Abstract Right ventricular (RV) enlargement and pulmonary valve insufficiency (PI) are well-known, unavoidable long term sequelae encountered by patients who undergo tetralogy of Fallot (TOF) surgery. Despite their lifelong need for cardiac surveillance and occasional re-intervention, there is a paucity of numerical data characterizing blood flows in their pulmonary arteries (PA). Specifically, although PA regurgitation is well-known to be ubiquitously present in adult repaired TOF (rTOF) patients yet, there have been only limited numerical studies to fully characterize this process. The few studies available have utilized idealized, simplistic geometric models or overly simplistic boundary conditions that fail to account for flow… More >

Dalin Tang^*, Chun Yang^†, Tal Geva^‡,§, Pedro J. del Nido^¶

Molecular & Cellular Biomechanics, Vol.4, No.3, pp. 159-176, 2007, DOI:10.3970/mcb.2007.004.159

Abstract A single-layer isotropic patient-specific right/left ventricle and patch (RV/LV/Patch) combination model with fluid-structure interactions (FSI) was introduced in our previous papers to evaluate and optimize human pulmonary valve replacement/insertion (PVR) surgical procedure and patch design. In this paper, an active anisotropic model with two-layer structure for ventricle wall and tissue fiber orientation was introduced to improve previous isotropic model for more accurate assessment of RV function and potential application in PVR surgery and patch design. A material-stiffening approach was used to model active heart contraction. The computational models were used to conduct ``virtual (computational)'' surgeries and test the hypothesis that… More >