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

Deficits in the Functional Muscle-Bone Unit in Youths with Fontan Physiology.

2021

202-207

2021 11

1097-6833

<p><strong>OBJECTIVE: </strong>To determine whether dual energy X-ray absorptiometry (DXA), a clinically available tool, mirrors the magnitude of deficits in trabecular and cortical bone mineral density (BMD) demonstrated on peripheral quantitative computed tomography in youth with Fontan physiology.</p>

<p><strong>STUDY DESIGN: </strong>We aimed to describe DXA-derived BMD at multiple sites and to investigate the relationship between BMD and leg lean mass, a surrogate for skeletal muscle loading. Subjects with Fontan (n&nbsp;=&nbsp;46; aged 5-20&nbsp;years) underwent DXA in a cross-sectional study of growth and bone and muscle health as described previously. Data from the Bone Mineral Density in Childhood Study were used to calculate age-, sex-, and race-specific BMD z-scores of the whole body, lumbar spine, hip, femoral neck, distal one-third radius, ultradistal radius, and leg lean mass z-score (LLMZ).</p>

<p><strong>RESULTS: </strong>Fontan BMD z-scores were significantly lower than reference at all sites-whole body, -0.34&nbsp;±&nbsp;0.85 (P&nbsp;=&nbsp;.01); spine, -0.41&nbsp;±&nbsp;0.96 (P&nbsp;=&nbsp;.008); hip, -0.75&nbsp;±&nbsp;1.1 (P&nbsp;&lt;&nbsp;.001); femoral neck, -0.73&nbsp;±&nbsp;1.0 (P&nbsp;&lt;&nbsp;.001); distal one-third radius, -0.87&nbsp;±&nbsp;1.1 (P&nbsp;&lt;&nbsp;.001); and ultradistal radius. -0.92&nbsp;±&nbsp;1.03 (P&nbsp;&lt;&nbsp;.001)-as was LLMZ (-0.93&nbsp;±&nbsp;1.1; P&nbsp;&lt;&nbsp;.001). Lower LLMZ was associated with lower BMD of the whole body (R&nbsp;=&nbsp;0.40; P&nbsp;&lt;&nbsp;.001), lumbar spine (R&nbsp;=&nbsp;0.16; P&nbsp;=&nbsp;.005), total hip (R&nbsp;=&nbsp;0.32; P&nbsp;&lt;&nbsp;.001), femoral neck (R&nbsp;=&nbsp;0.47; P&nbsp;&lt;&nbsp;.001), and ultradistal radius (R&nbsp;=&nbsp;0.35; P&nbsp;&lt;&nbsp;.001).</p>

<p><strong>CONCLUSIONS: </strong>Patients with Fontan have marked deficits in both cortical (hip, distal one-third radius) and trabecular (lumbar spine, femoral neck, ultradistal radius) BMD. Lower LLMZ is associated with lower BMD and may reflect inadequate skeletal muscle loading. Interventions to increase muscle mass may improve bone accrual.</p>

10.1016/j.jpeds.2021.06.068

J Pediatr

34214589

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

Deficits in bone density and structure in children and young adults following Fontan palliation.

2015

12-6

2015 Aug

1873-2763

<p><strong>BACKGROUND: </strong>Survival of patients with congenital heart disease has improved such that there are now more adults than children living with these conditions. Complex single ventricle congenital heart disease requiring Fontan palliation is associated with multiple risk factors for impaired bone accrual. Bone density and structure have not been characterized in these patients.</p>

<p><strong>METHODS: </strong>Tibia peripheral quantitative computed tomography (pQCT) was used to assess trabecular and cortical volumetric bone mineral density (vBMD), cortical dimensions, and calf muscle area in 43 Fontan participants (5-33 years old), a median of 10 years following Fontan palliation. pQCT outcomes were converted to sex- and race-specific Z-scores relative to age based on &gt;700 healthy reference participants. Cortical dimensions and muscle area were further adjusted for tibia length.</p>

<p><strong>RESULTS: </strong>Height Z-scores were lower in Fontan compared to reference participants (mean ± SD: -0.29 ± 1.00 vs. 0.25 ± 0.93, p &lt; 0.001); BMI Z-scores were similar (0.16 ± 0.88 vs. 0.35 ± 1.02, p = 0.1). Fontan participants had lower trabecular vBMD Z-scores (-0.85 ± 0.96 vs. 0.01 ± 1.02, p &lt; 0.001); cortical vBMD Z-scores were similar (-0.17 ± 0.98 vs. 0.00 ± 1.00, p = 0.27). Cortical dimensions were reduced with lower cortical area (-0.59 ± 0.84 vs. 0.00 ± 0.88, p&lt;0.001) and periosteal circumference (-0.50 ± 0.82 vs. 0.00 ± 0.84, p &lt; 0.001) Z-scores, compared to reference participants. Calf muscle area Z-scores were lower in the Fontan participants (-0.45 ± 0.98 vs. 0.00 ± 0.96, p = 0.003) and lower calf muscle area Z-scores were associated with smaller periosteal circumference Z-scores (R = 0.62, p &lt; 0.001). Musculoskeletal deficits were not associated with age, Fontan characteristics, parathyroid hormone or vitamin D levels.</p>

<p><strong>CONCLUSIONS: </strong>Children and young adults demonstrate low trabecular vBMD, cortical structure and muscle area following Fontan. Muscle deficits were associated with smaller periosteal dimensions. Future studies should determine the fracture implications of these deficits and identify interventions to promote musculoskeletal development.</p>

10.1016/j.bone.2015.04.012

Bone

25882907

Lean mass deficits, vitamin D status and exercise capacity in children and young adults after Fontan palliation.

2014

1702-7

2014 Nov

1468-201X

<p><strong>OBJECTIVE: </strong>We sought to evaluate body composition in children and young adults with Fontan physiology. Leg lean mass (LM) deficits correlate with diminished exercise capacity in other populations and may contribute to exercise limitations in this cohort.</p>

<p><strong>METHODS: </strong>This cross-sectional study included whole body dual energy X-ray absorptiometry scans in 50 Fontan participants ≥5 years, and measures of peak oxygen consumption (VO2) in 28. Whole body and leg LM (a measure of skeletal muscle) were converted to sex- and race-specific Z-scores, relative to age and stature, based on 992 healthy reference participants.</p>

<p><strong>RESULTS: </strong>Median age was 11.5 (range 5.1-33.5) years at 9.3 (1.1-26.7) years from Fontan. Height Z-scores were lower in Fontan compared with reference participants (-0.47±1.08 vs 0.25±0.93, p&lt;0.0001). Body mass index Z-scores were similar (0.15±0.98 vs 0.35±1.02, p=0.18). LM Z-scores were lower in Fontan compared with reference participants (whole body LM -0.33±0.77 vs 0.00±0.74, p=0.003; leg LM -0.89±0.91 vs 0.00±0.89, p&lt;0.0001). LM Z-scores were not associated with age or Fontan characteristics. Leg LM Z-scores were lower in vitamin D deficient versus sufficient Fontan participants (-1.47±0.63 vs -0.71±0.92, p=0.01). Median per cent predicted peak VO2 was 81% (range 13%-113%) and was associated with leg LM Z-scores (r=0.54, p=0.003).</p>

<p><strong>CONCLUSIONS: </strong>Following Fontan, children and young adults are shorter than their peers and have significant LM deficits. Skeletal muscle deficits were associated with vitamin D deficiency and reduced exercise capacity. Future studies should examine the progression of these deficits to further understand the contribution of peripheral musculature to Fontan exercise capacity.</p>

10.1136/heartjnl-2014-305723

Heart

24973081

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

The value of measuring systemic to pulmonary arterial collateral flow in Fontan patients.

2020

104-105

2020 10 01

1874-1754

10.1016/j.ijcard.2020.04.061

Int J Cardiol

32339544

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

Prevalence and Cause of Early Fontan Complications: Does the Lymphatic Circulation Play a Role?

2020

e015318

2020 Apr 07

2047-9980

<p><strong>Background</strong> Recent studies suggest that lymphatic congestion plays a role in development of late Fontan complications, such as protein-losing enteropathy. However, the role of the lymphatic circulation in early post-Fontan outcomes is not well defined.</p>

<p><strong>Methods and Results</strong> This was a retrospective, single-center study of patients undergoing first-time Fontan completion from 2012 to 2017. The primary outcome was ≤6&nbsp;months after surgery, a composite of death, Fontan takedown, extracorporeal membrane oxygenation, chest tube drainage &gt;14&nbsp;days, cardiac catheterization, readmission, or transplant. Complication causes were assigned to 1 of 4 groups: (1) Fontan circuit obstruction, (2) ventricular dysfunction or atrioventricular valve regurgitation, (3) persistent pleural effusions Fontan obstruction or ventricular dysfunction, and (4) chylothorax or plastic bronchitis. T2-weighted magnetic resonance imaging sequences were used to assess for lymphatic perfusion abnormality. The cohort consisted of 238 patients. Fifty-eight (24%) developed early complications: 20 of 58 (34.5%) in group 1, 8 of 58 (14%) in group 2, 18 of 58 (31%) in group 3, and 12 of 58 (20%) in group 4. Preoperative T2 imaging was available for 126 (53%) patients. Patients with high-grade lymphatic abnormalities had 6 times greater odds of developing early complications (=0.001).</p>

<p><strong>Conclusions </strong>There is substantial morbidity in the early post-Fontan period. Half of those who developed early complications had lymphatic failure or persistent effusions unrelated to structural or functional abnormalities. Preoperative T2 imaging demonstrated that patients with higher-grade lymphatic perfusion abnormalities were significantly more likely to develop early complications. This has implications for risk stratification and optimization of patients before Fontan palliation.</p>

10.1161/JAHA.119.015318

J Am Heart Assoc

32223393

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