Flow during exercise in the total cavopulmonary connection measured by magnetic resonance velocity mapping

Pedersen, Erik Morre; Stenbøg, Elisabeth; Fründ, Torben; Houlind, Kim Christian; Kromann, O.; Sørensen, Keld E.; Emmertsen, K; Hjortdal, Vibeke E.

doi:10.1136/heart.87.6.554

Cited by 69 publications

(59 citation statements)

References 20 publications

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“…Note that the SVC flowrate is synchronized with the heart cycle, while the IVC flowrate is synchronized with the respiratory cycle. Cardiac catheterization pressure tracings, echocardiography, and MR studies have all demonstrated that respiration significantly effects Fontan flow rates and pressures [15,30]. As seen with the echocardiographic tracings, quantitative real-time phase contrast MR measurements by Hjortdal et al [15] show that flow rates in the IVC vary significantly with respiration at rest (as much as 80%), with smaller cardiac pulsatility superimposed.…”

Section: Simulation Resultsmentioning

confidence: 75%

Computational fluid–structure interaction: methods and application to a total cavopulmonary connection

et al. 2009

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The Fontan procedure is a surgery that is performed on single-ventricle heart patients, and, due to the wide range of anatomies and variations among patients, lends itself nicely to study by advanced numerical methods. We focus on a patient-specific Fontan configuration, and perform a fully coupled fluid-structure interaction (FSI) analysis of hemodynamics and vessel wall motion. To enable physiologically realistic simulations, a simple approach to constructing a variable-thickness blood vessel wall description is proposed. Rest and exercise conditions are simulated and rigid versus flexible vessel wall simulation results are compared. We conclude that flexible wall modeling plays an important role in predicting quantities of hemodynamic interest in the Fontan connection. To the best of our knowledge, this paper presents the first three-dimensional patientspecific fully coupled FSI analysis of a total cavopulmonary connection that also includes large portions of the pulmonary circulation.

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Section: Simulation Resultsmentioning

confidence: 75%

Computational fluid–structure interaction: methods and application to a total cavopulmonary connection

et al. 2009

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“…If differences in power loss for different flow splits to the pulmonary arteries are magnified at exercise conditions, this could result in either changes in relative pulmonary blood flow or in additional inefficiencies of the TCPC. If flow splits remain the same with exercise, as suggested by studies from Pedersen et al, 16 but the optimal flow split for minimizing power loss is different, this could result in further TCPC inefficiencies.…”

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confidence: 97%

Nonlinear Power Loss During Exercise in Single-Ventricle Patients After the Fontan

et al. 2007

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Background-We previously demonstrated that power loss (PL) through the total cavopulmonary connection (TCPC) in single-ventricle patients undergoing Fontan can be calculated by computational fluid dynamic analysis using 3-dimensional MRI anatomic reconstructions. PL through the TCPC may play a role in single-ventricle physiology and is a function of cardiac output. We hypothesized that PL through the TCPC increases significantly under exercise flow conditions. Methods and Results-MRI data of 10 patients with a TCPC were analyzed to obtain 3-dimensional geometry and flow rates through the superior vena cava, inferior vena cava, left pulmonary artery, and right pulmonary artery. Steady computational fluid dynamic simulations were performed at baseline conditions using MRI-derived flows. Simulated exercise conditions of twice (2ϫ) and three times (3ϫ) baseline flow were performed by increasing inferior vena cava flow. PL, head loss, and effective resistance through the TCPC were calculated for each condition. Each condition was repeated at left pulmonary artery/right pulmonary artery ratios of 30/70 and 70/30 to determine the effects of pulmonary flow splits on exercise PL. For each patient, PL increases dramatically in a nonlinear fashion with increasing cardiac output, even when normalized to calculate head loss or resistance. Flow splits had a significant effect on PL at exercise, with most geometries favoring right pulmonary artery flow. Conclusions-The relationship between cardiac output and PL is nonlinear and highly dependent on TCPC geometry and pulmonary flow splits. This study demonstrates the importance of studying the TCPC under exercise conditions, because baseline conditions may not adequately characterize TCPC efficiency.

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“…In Fontan patients, PA flow has been studied directly after supine bicycle exercise with magnetic resonance imaging (MRI) (16). However, this study did not look into the reaction of the PAs on an increase in flow.…”

mentioning

confidence: 99%

“…Recent studies on the effects of exercise on caval vein and pulmonary artery flow after Fontan operation have emphasized the need for evaluation of the Fontan circulation under exercise conditions (15,16). In Fontan patients, PA flow has been studied directly after supine bicycle exercise with magnetic resonance imaging (MRI) (16).…”

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confidence: 99%

Pulmonary artery size and function after Fontan operation at a young age

Robbers‐Visser

Helderman

Strengers

et al. 2008

Magnetic Resonance Imaging

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Purpose: To assess pulmonary artery (PA) size, flow variables, and wall shear stress (WSS) in patients after Fontan operation at a young age. Materials and Methods:Flow in the branch PA was obtained with phase contrast velocity-encoded cardiovascular magnetic resonance imaging in 14 patients before and after low-dose dobutamine stress (7.5 g/kg/min) and in 17 healthy controls at rest.Results: At rest, stroke index, total flow, average, and peak flow rate were all statistically significantly lower in patients than in controls (P Ͻ 0.001). With stress-testing, all variables increased in patients (P Ͻ 0.001), apart from stroke index, which did not change. At rest, branch PA area did not differ between patients and controls. Distensibility was lower in patients than in controls (P Ͻ 0.001). With stresstesting, area and distensibility did not change. At rest, WSS was lower in patients than in controls (P Ͻ 0.001). WSS increased with stress-testing (P Ͻ 0.001), but not to the same levels as during resting conditions of the control group.Conclusion: PA size is normal long-term after Fontan operation at a young age. Flow variables, distensibility, and WSS are significantly lower compared to healthy controls, and do not show adequate reactions with stress-testing, which is suggestive of pulmonary artery endothelial and/or vascular dysfunction.

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Flow during exercise in the total cavopulmonary connection measured by magnetic resonance velocity mapping

Cited by 69 publications

References 20 publications

Computational fluid–structure interaction: methods and application to a total cavopulmonary connection

Computational fluid–structure interaction: methods and application to a total cavopulmonary connection

Nonlinear Power Loss During Exercise in Single-Ventricle Patients After the Fontan

Pulmonary artery size and function after Fontan operation at a young age

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