Determination of Contrast Timing by Time-Resolved Magnetic Resonance Angiography in Patients With Bidirectional Glenn and Hemi-Fontan Anastomoses.

2022

742-746

05/2022

1532-3145

PURPOSE: Children with single-ventricle congenital heart disease undergo a series of operations to maintain their pulmonary circulation including bidirectional Glenn (BDG) or hemi-Fontan in the second stage to create a superior cavopulmonary anastomosis. We aimed to optimize cardiovascular angiography protocols by determining optimal contrast timing of pulmonary and systemic circulation on magnetic resonance angiography (MRA) performed with the technique of time-resolved imaging with interleaved stochastic trajectories (TWIST).

METHODS AND MATERIALS: Cardiac TWIST MRA with lower extremity (LE) contrast injection was analyzed in 92 consecutive patients with a BDG or hemi-Fontan anastomosis. Contrast arrival time to inferior vena cava was set to zero to determine the relative time-to-peak (TTP) of the target vessels. Time-to-peak of each vessel was compared by age (<2 or ≥2 y), ejection fraction (<54% or ≥54%), the median values of heart rate (<111 or ≥111 beats per minute), body surface area (BSA, <0.59 or ≥0.59), cardiac index (<6.04 or ≥6.04), and indexed ascending aorta flow (AscAo_i, <5.3 or ≥5.3). The TTP of the vessels was also correlated with the volumetric parameters.

RESULTS: The mean age of 92 patients (32 female, 60 male) was 3.1 years (0.7-5.6 years). With LE injection, the first peak was depicted in AscAo. Time-to-peak of the pulmonary arteries was approximately 9 seconds later than AscAo. The TTP difference between pulmonary arteries and AscAo was shorter in high heart rate group (8.3 vs 10 seconds, P < 0.001). The TTP difference between AscAo and the mean of pulmonary arteries was significantly shorter in high cardiac index group (8.4 vs 9.9 seconds, P < 0.01) and high AscAo_i group (8.7 vs 9.7 seconds, P = 0.03). The TTP differences were not significant by age, ejection fraction, and BSA. Cardiac index and AscAo_i were negatively correlated with all TTPs except AscAo. The ejection fraction, stroke volume, and atrioventricular regurgitation fraction did not correlate with the TTP.

CONCLUSIONS: In patients with BDG or hemi-Fontan anastomosis, TTP of the pulmonary arteries on TWIST MRA via LE intravenous injection is approximately 9 seconds later than AscAo, approximately 8 and 10 seconds later in high and low heart rate groups, respectively. Cardiac index and AscAo_i have less effect on the TTP than the heart rate. There was no TTP difference of the pulmonary arteries by age, BSA, and ejection fraction and no correlation with ejection fraction, stroke volume, and atrioventricular regurgitation fraction. These data can be used to guide timing of pulmonary arterial enhancement of single-ventricle patients after BDG or hemi-Fontan anastomosis.

10.1097/RCT.0000000000001332

J Comput Assist Tomogr

35617648

Tricuspid annular plane systolic excursion does not correlate with right ventricular ejection fraction in patients with hypoplastic left heart syndrome after Fontan palliation.

2014

1253-8

2014 Oct

1432-1971

<p>Tricuspid annular plane systolic excursion (TAPSE) reflects longitudinal myocardial shortening, the main component of right ventricular (RV) contraction in normal hearts. To date, TAPSE has not been extensively studied in patients with hypoplastic left heart syndrome (HLHS) and systemic RVs after Fontan palliation. This retrospective study investigated HLHS patients after Fontan with cardiac magnetic resonance (CMR) performed between 1 January 2010 and 1 August 2012 and transthoracic echocardiogram (TTE) performed within 6 months of CMR. The maximal apical displacement of the lateral tricuspid valve annulus was measured on CMR (using four-chamber cine images) and on TTE (using two-dimensional apical views). To create TTE-TAPSE z-scores, published reference data were used. Intra- and interobserver variability was tested with analysis of variance. Inter-technique agreement of TTE and CMR was tested with Bland-Altman analysis. In this study, 30 CMRs and TTEs from 29 patients were analyzed. The age at CMR was 14.1 ± 7.1 years, performed 11.9 ± 7.8 years after Fontan. For CMR-TAPSE, the intraclass correlation coefficients for inter- and intraobserver variability were 0.89 and 0.91, respectively. The TAPSE measurements were 0.57 ± 0.2 cm on CMR and 0.70 ± 0.2 cm on TTE (TTE-TAPSE z score, -8.7 ± 1.0). The mean difference in TAPSE between CMR and TTE was -0.13 cm [95 % confidence interval (CI) -0.21 to -0.05], with 95 % limits of agreement (-0.55 to 0.29 cm). The study showed no association between CMR-TAPSE and RVEF (R = 0.08; p = 0.67). In patients with HLHS after Fontan, TAPSE is reproducible on CMR and TTE, with good agreement between the two imaging methods. Diminished TAPSE suggests impaired longitudinal shortening in the systemic RV. However, TAPSE is not a surrogate for RVEF in this study population.</p>

10.1007/s00246-014-0924-4

Pediatr Cardiol

24840648

Leg lean mass correlates with exercise systemic output in young Fontan patients.

2018

680-684

2018 04

1468-201X

<p><strong>OBJECTIVE: </strong>We previously described lower leg lean mass Z-scores (LLMZ) in Fontan patients associated with worse peak oxygen consumption on metabolic exercise testing. We hypothesised that LLMZ correlates with indexed systemic flow (Qsi) and cardiac index (CI) on exercise cardiac magnetic resonance (eCMR).</p>

<p><strong>METHODS: </strong>Thirteen patients had LLM measured by dual-energy X-ray absorptiometry within mean 40 (range 0-258) days of eCMR. LLM was converted to sex and race-specific Z-scores based on healthy reference data. Ventricular volumes and flow measurements of the ascending and descending (DAO) aorta and superior vena cava (SVC) were obtained by CMR at rest and just after supine ergometer exercise to a heart rate associated with anaerobic threshold on prior exercise test. Baseline and peak exercise measures of Qsi (SVC+DAO/BSA) and CI, as well as change in Qsi and CI with exercise, were compared with LLMZ by linear regression.</p>

<p><strong>RESULTS: </strong>LLMZ was not correlated with resting flows, stroke volume or CI. There was a strong linear correlation between LLMZ and change in both CI (r=0.77, p=0.002) and Qsi (r=0.73, p=0.005) from rest to exercise. There was also a significant correlation between LLMZ and Qsi at exercise (r=0.70, p=0.008). The correlation between LLMZ and CI at exercise did not reach significance (r=0.3, p=0.07).</p>

<p><strong>CONCLUSIONS: </strong>In our cohort, there was a strong linear correlation between LLMZ and change in both CI and Qsi from rest to exercise, suggesting that Fontan patients with higher LLMZ may be better able to augment systemic output during exercise, improving performance.</p>

10.1136/heartjnl-2017-311661

Heart

28988207

Optimizing neonatal cardiac imaging (magnetic resonance/computed tomography).

2021

2021 Oct 17

1432-1998

<p>Magnetic resonance imaging (MRI) and CT perform an important role in the evaluation of neonates with congenital heart disease (CHD) when echocardiography is not sufficient for surgical planning or postoperative follow-up. Cardiac MRI and cardiac CT have complementary applications in the evaluation of cardiovascular disease in neonates. This review focuses on the indications and technical aspects of these modalities and special considerations for imaging neonates with CHD.</p>

10.1007/s00247-021-05201-w

Pediatr Radiol

34657169

Pearls and Pitfalls in Pediatric Fontan Operation Imaging.

2020

442-450

2020 Oct

1558-5034

<p>The Fontan operation or the total cavopulmonary connection is a palliative surgery for single ventricle congenital heart disease where the systemic venous return circumvents a pumping chamber and flows directly into the pulmonary circuit. With surgical and medical advances, there has been improvement in life expectancy of these patients, however, it has also resulted in unique complications from the physiology that requires diligent surveillance. A critical component relies on optimal imaging for diagnosis and treatment of these complications. This article describes the normal anatomy of the Fontan circulation, current imaging modalities and techniques, and frequently encountered complications seen when imaging the patients who have undergone Fontan palliation.</p>

10.1053/j.sult.2020.05.009

Semin. Ultrasound CT MR

32980091

Protein Losing Enteropathy After Fontan Operation: Glimpses of Clarity Through the Lifting Fog.

2020

92-96

2020 Jan

2150-136X

<p>Fontan-associated protein losing enteropathy is a challenge to treat and is a major contributor to morbidity and mortality in patients with palliated single ventricle. Numerous strategies for management have been proposed, with confusion as to how best to stratify and implement care among the many treatments available. Medical management can be helpful in some, while novel lymphatic interventions hold potential for remission with good results. We review our institutional approach to protein losing enteropathy after Fontan operation and provide a suggested algorithm and pathway for effective care.</p>

10.1177/2150135119890555

World J Pediatr Congenit Heart Surg

31835975

MRI Evaluation of Lymphatic Abnormalities in the Neck and Thorax after Fontan Surgery: Relationship with Outcome.

2019

180877

2019 Apr 02

1527-1315

<p>Background The Fontan operation is performed for surgical palliation of single ventricle physiology. This operation is usually preceded by a superior cavopulmonary connection (SCPC); lymphatic abnormalities after SCPC may be demonstrated at MRI and prior to the Fontan operation. Purpose To determine if the degree of neck and thoracic lymphatic abnormalities at T2-weighted MRI in patients after superior cavopulmonary connection (SCPC) correlated with surgical outcomes from the Fontan procedure. Materials and Methods Patients for whom SCPC was performed for palliation of single ventricle disease who underwent chest MRI between July 2012 and May 2015 at a single institution were retrospectively reviewed. T2-weighted images were scored as lymphatic type 1 (little or no T2 mediastinal and supraclavicular signal) to type 4 (T2 signal into both the mediastinum and the lung parenchyma). Fontan takedown, duration of post-Fontan hospitalization and pleural effusion, postoperative plastic bronchitis, need for transplant, and mortality were tabulated. The relationship between lymphatic type and clinical outcomes was evaluated by using analysis of variance (ANOVA), the Kruskal-Wallis H test, and the Fisher exact test. Results A total of 83 patients (mean age, 7.9 years ± 2.6) were evaluated. Among these 83 patients, 53 (64%) were classified with type 1 or 2 lymphatic abnormalities, 17 (20%) with type 3, and 12 (16%) with type 4. The rate of failure of Fontan completion was higher in patients with type 4 than in type 1 or 2 (54% vs 2%, respectively; P = .004). Need for cardiac transplant (one of 13 [8%]) and death (three of 13 [23%]) occurred only in type 4. Median postoperative length of stay was longer for patients with type 4 than for those with types 1 or 2 (29 days vs 9 days, respectively; P &lt; .01). Conclusion Greater MRI-based severity of lymphatic abnormalities in patients prior to planned Fontan procedure was associated with failure of Fontan completion and longer postoperative stay. © RSNA, 2019 Online supplemental material is available for this article.</p>

10.1148/radiol.2019180877

Radiology

30938628

Accuracy of Phase-Contrast Velocity Mapping Proximal and Distal to Stent Artifact During Cardiac Magnetic Resonance Imaging.

2018

1634-8

2018 Jun 15

1879-1913

<p>Little data are available on the accuracy of phase-contrast magnetic resonance imaging (PC-MRI) velocity mapping in the vicinity of intravascular metal stents other than nitinol stents. Therefore, we sought to determine this accuracy using in vitro experiments. An in vitro flow phantom was used with 3 stent types: (1) 316L stainless steel, (2) nitinol self-expanding, and (3) platinum-iridium. Steady and pulsatile flow was delivered with a magnetic resonance imaging-compatible pump (CardioFlow 5000, Shelley Medical, London, Ontario, Canada). Flows were measured using a transit time flow meter (ME13PXN, Transonic, Inc, Ithaca, New York). Mean flows ranged from 0.5 to 7 L/min. For each condition, 5 PC-MRI acquisitions were made: within the stent, immediately adjacent to both edges of the stent artifact, and 1 cm upstream and downstream of the artifact. Mean PC-MRI flows were calculated by segmenting the tube lumen using clinical software (ARGUS, Siemens, Inc, Erlangen, Germany). PC-MRI and flow meter flows were compared by location and stent type using linear regression, Bland-Altman, and intraclass correlation (ICC). PC-MRI flows within the stent artifact were inaccurate for all stents studied, generally underestimating flow meter-measured flow. Agreement between PC-MRI and flow meter-measured flows was excellent for all stent types, both immediately adjacent to and 1 cm away from the edge of the stent artifact. Agreement was highest for the platinum-iridium stent (R = 0.999, ICC = 0.999) and lowest for the nitinol stent (R = 0.993, ICC = 0.987). In conclusion, PC-MRI flows are highly accurate just upstream and downstream of a variety of clinically used stents, supporting its use to directly measure flows in stented vessels.</p>

10.1016/j.amjcard.2018.02.050

Am. J. Cardiol.

29776653

Hepatic Fibrosis Is Universal Following Fontan Operation, and Severity is Associated With Time From Surgery: A Liver Biopsy and Hemodynamic Study.

2017

2017 Apr 26

2047-9980

<p><strong>BACKGROUND: </strong>Congestive hepatopathy is a recognized complication of Fontan physiology. Data regarding the incidence of hepatopathy and risk factors are lacking.</p>

<p><strong>METHODS AND RESULTS: </strong>Liver biopsies and cardiac catherizations were performed as part of an evaluation offered to all patients ≥10&nbsp;years after Fontan. Quantitative determination of hepatic fibrosis was performed using Sirius red staining with automated calculation of collagen deposition per slide (%CD). Biopsies from included subjects were compared to stained specimens from controls without known fibrotic liver disease. Patient characteristics, echocardiographic findings, and hemodynamic measures were evaluated as potential risk factors. The cohort consisted of 67 patients (31 female) at mean age of 17.3±4.5&nbsp;years and mean time from Fontan of 14.9±4.5&nbsp;years. Right ventricular morphology was present in 37 subjects. Median %CD by Sirius red staining was 21.6% (range 8.7% to 49.4%) compared to 2.6% (range 2.2% to 3.0%) in controls. There was a significant correlation between time from Fontan and degree of Sirius red staining (r=0.33, P&lt;0.01). Serum liver enzymes and platelet count did not correlate with %CD. The median inferior vena cava pressure was 13&nbsp;mm&nbsp;Hg (range 6-24&nbsp;mm&nbsp;Hg) and did not correlate with %CD. There was no difference in %CD based on ventricular morphology or severity of atrioventricular valve insufficiency.</p>

<p><strong>CONCLUSIONS: </strong>In this cohort of predominantly asymptomatic children and adolescents electively evaluated after a Fontan operation, all exhibited evidence for hepatic fibrosis as measured by collagen deposition in the liver. Time from Fontan was the only factor significantly associated with collagen deposition. These findings demonstrate that liver fibrosis is an inherent feature of Fontan physiology and that the degree of fibrosis increases over time.</p>

10.1161/JAHA.116.004809

J Am Heart Assoc

28446492