Pulmonary regurgitation: The effects of varying pulmonary artery compliance, and of increased resistance proximal or distal to the compliance

Kilner, Philip J.; Balossino, Rossella; Dubini, Gabriele; Babu‐Narayan, Sonya V.; Pennati, Giancarlo; Migliavacca, Francesco

doi:10.1016/j.ijcard.2008.06.078

Cited by 65 publications

(44 citation statements)

References 28 publications

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“…In occasional cases, the regurgitant fraction can exceed 50% [48]. This may be attributable to an unusually large and compliant RV, to a large and compliant pulmonary trunk and PA branches whose recoil contributes to the regurgitation [49], to branch PA stenosis or elevated peripheral resistance limiting the distal escape of flow or to combinations of these [50]. In summary, the evaluation of repaired ToF requires thorough assessment of the left and right heart, extending to the branch PAs and ascending aorta.…”

Section: Repaired Tetralogy Of Fallotmentioning

confidence: 99%

Imaging congenital heart disease in adults

Kilner¹

2011

BJR

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ABSTRACT. Transthoracic echocardiography is the first-line modality for cardiovascular imaging in adults with congenital heart disease (ACHD). The windows of access that are possible with transthoracic echocardiography are, however, rarely adequate for all regions of interest. The choice of further imaging depends on the clinical questions that remain to be addressed. The strengths of MRI include comprehensive access and coverage, providing imaging of all parts of the right ventricle, the pulmonary arteries, pulmonary veins and aorta. Cine images and velocity maps are acquired in specifically aligned planes, with stacks of cines or dynamic contrast angiography providing more comprehensive coverage. Tissues can be characterised if necessary, and MRI provides relatively accurate measurements of biventricular function and volume flow. These parameters are important in the assessment and follow-up of adults after repairs for tetralogy of Fallot or transposition of the great arteries and after Fontan operations. The superior spatial resolution and rapid acquisition of CT are invaluable in selected situations, including the visualisation of anomalous coronary or aortopulmonary collateral arteries, the assessment of luminal patency after stenting and imaging in patients with pacemakers. Ionising radiation is, however, a concern in younger patients who may need repeated investigation. Adults with relatively complex conditions should ideally be imaged in a specialist ACHD centre, where dedicated echocardiographic and cardiovascular MRI services are a necessary facility. General radiologists should be aware of the nature and pathophysiology of congenital heart disease, and should be alert for previously undiagnosed cases presenting in adulthood, including cases of atrial septal defect, aortic coarctation, patent ductus arteriosus, double-chambered right ventricle and congenitally corrected transposition.

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Section: Repaired Tetralogy Of Fallotmentioning

confidence: 99%

Imaging congenital heart disease in adults

Kilner¹

2011

BJR

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“…Namely, it was assumed that r R ¼ 0.7, r C ¼ 0.3 and t ¼ 0.00625 s for both lungs, on the basis of values adopted in previous LPM models of pulmonary vasculature [11][12][13] and clinical measurements [14].…”

Section: Multi-scale Modelsmentioning

confidence: 99%

Boundary conditions of patient-specific fluid dynamics modelling of cavopulmonary connections: possible adaptation of pulmonary resistances results in a critical issue for a virtual surgical planning

et al. 2011

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Cavopulmonary connections are surgical procedures used to treat a variety of complex congenital cardiac defects. Virtual pre-operative planning based on in silico patient-specific modelling might become a powerful tool in the surgical decision-making process. For this purpose, three-dimensional models can be easily developed from medical imaging data to investigate individual haemodynamics. However, the definition of patient-specific boundary conditions is still a crucial issue. The present study describes an approach to evaluate the vascular impedance of the right and left lungs on the basis of pre-operative clinical data and numerical simulations. Computational fluid dynamics techniques are applied to a patient with a bidirectional cavopulmonary anastomosis, who later underwent a total cavopulmonary connection (TCPC). Multi-scale models describing the surgical region and the lungs are adopted, while the flow rates measured in the venae cavae are used at the model inlets. Pre-operative and post-operative conditions are investigated; namely, TCPC haemodynamics, which are predicted using patient-specific pre-operative boundary conditions, indicates that the pre-operative balanced lung resistances are not compatible with the TCPC measured flows, suggesting that the pulmonary vascular impedances changed individually after the surgery. These modifications might be the consequence of adaptation to the altered pulmonary blood flows.

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“…Regurgitation results from the absence of a functioning pulmonary valve that maintains one-way blood flow from the right ventricle to the pulmonary artery. Previous ToF blood flow simulations have investigated regurgitation with lumped (Kilner et al, 2009) or idealized (geometry and boundary conditions) three-dimensional (Chern et al, 2008) models, as well as pressure losses for two repair options with either a one-dimensional (Spilker et al, 2007) or a steady three-dimensional (Chai et al, 2010) patient-specific model. In this paper, we combined realistic models of form (three-dimensional geometries) and function (physiological inflow and outlet boundary conditions) as in (Das et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

Group-wise construction of reduced models for understanding and characterization of pulmonary blood flows from medical images

Guibert

McLeod

Caiazzo

et al. 2014

Medical Image Analysis

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Abstract3D computational fluid dynamics (CFD) in patient-specific geometries provides complementary insights to clinical imaging, to better understand how heart disease, and the side effects of treating heart disease, affect and are affected by hemodynamics. This information can be useful in treatment planning for designing artificial devices that are subject to stress and pressure from blood flow. Yet, these simulations remain relatively costly within a clinical context. The aim of this work is to reduce the complexity of patient-specific simulations by combining image analysis, computational fluid dynamics and model order reduction techniques. The proposed method makes use of a reference geometry estimated as an average of the population, within an efficient statistical framework based on the currents representation of shapes. Snapshots of blood flow simulations performed in the reference geometry are used to build a POD (Proper Orthogonal Decomposition) basis, which can then be mapped on new patients to perform reduced order blood flow simulations with patient specific boundary conditions. This approach is applied to a data-set of 17 tetralogy of Fallot patients to simulate blood flow through the pulmonary artery under normal (healthy or synthetic valves with almost no backflow) and pathological (leaky or absent valve with backflow) conditions to better understand the impact of regurgitated blood on pressure and velocity at the outflow tracts.The model reduction approach is further tested by performing patient simulations under exercise and varying degrees of pathophysiological conditions based on reduction of reference solutions (rest and medium backflow conditions respectively).

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Pulmonary regurgitation: The effects of varying pulmonary artery compliance, and of increased resistance proximal or distal to the compliance

Cited by 65 publications

References 28 publications

Imaging congenital heart disease in adults

Imaging congenital heart disease in adults

Boundary conditions of patient-specific fluid dynamics modelling of cavopulmonary connections: possible adaptation of pulmonary resistances results in a critical issue for a virtual surgical planning

Group-wise construction of reduced models for understanding and characterization of pulmonary blood flows from medical images

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