Aortic Root Dilatation and Aortic-Related Complications in Children After Tetralogy of Fallot Repair

Adverse remodelling in tetralogy of Fallot: From risk factors to imaging analysis and future perspectives

Although contemporary outcomes of initial surgical repair of tetralogy of Fallot (TOF) are excellent, the survival of adult patients remains significantly lower than that of the normal population due to the high incidence of heart failure, ventricular arrhythmias, and sudden cardiac death. The underlying mechanisms are only partially understood but involve an adverse biventricular response, so-called remodelling, to key stressors such as right ventricular (RV) pressure-and/or volume-overload, myocardial fibrosis, and electro-mechanical dyssynchrony. In this review, we explore risk factors and mechanisms of biventricular remodelling, from histological to electro-mechanical aspects, and the role of imaging in their assessment. We discuss unsolved challenges and future directions to better understand and treat the long-term sequelae of this complex congenital heart disease.

A Severe and Fatal Type A Aortic Dissection in an Adult with a Repaired Tetralogy of Fallot

We report a case of a 44-year-old woman surgically treated for tetralogy of Fallot who experienced an acute and extensive Stanford A type aortic dissection despite the meticulous follow-up. While aortic dilatation is prevalent in individuals with repaired tetralogy of Fallot, aortic dissection represents a rare consequence, that when it appears, is progressive and usually detected during the check-up visits. In the case reported, the dissection was unexpected and severe, and the patient's clinical state worsened suddenly, leading to death after a few days. Constant awareness for aortic aneurysms is essential in the Fallot tetralogy population, nevertheless, several causes may contribute to the acute worsening of the clinical condition until the patient's death.

Natural history of aortic root dilatation and pathologic aortic regurgitation in tetralogy of Fallot and its morphological variants

OBJECTIVE

We sought to characterize the natural history of aortic root dilatation and aortic regurgitation in tetralogy of Fallot (TOF).

METHODS

A single-center review of patients who underwent TOF repair from January 1960 to December 2022 was performed. Morphology was categorized as TOF-pulmonary stenosis or TOF-variant (including TOF-pulmonary atresia and TOF-pulmonary atresia-major aortopulmonary collateral arteries). Echocardiographically determined diameters and derived z scores were measured at the annulus, sinus of Valsalva, and sinotubular junction immediately before TOF repair and throughout follow-up. Linear mixed-effects models assessed trends in dimensions over time.

RESULTS

Of 2205 patients who underwent primary repair of TOF at a median age of 4.9 months (interquartile range, 2.3-20.5 months) and survived to discharge, 1608 (72.9%) patients had TOF-pulmonary stenosis and 597 (27.1%) patients had TOF-variant. At a median postoperative follow-up of 14.4 years (interquartile range, 3.3-27.6 years; range, 0.1-62.6 years), 313 (14.2%) patients had mild or greater aortic regurgitation and 34 (1.5%) patients required an aortic valve or root intervention. The overall mean rates of annular, sinus of Valsalva, and sinotubular junction growth were 0.5 ± 0.2, 0.6 ± 0.3, and 0.7 ± 0.5 mm/year, respectively. Root z scores remained stable with time. At baseline, patients with TOF-variant had larger diameters and z scores at the annulus, sinus of Valsalva, and sinotubular junction, compared with patients with TOF-pulmonary stenosis (all P values < .05). Over time, patients with TOF-variant demonstrated relatively greater annular (P = .020), sinus of Valsalva (P < .001), and sinotubular junction (P < .001) dilatation. Patients with ≥75th percentile root growth rates had a higher incidence of mild or greater aortic regurgitation (P < .001), moderate or greater aortic regurgitation (P < .001), and aortic valve repair or replacement (P = .045).

CONCLUSIONS

Patients with TOF-variant are at comparatively greater risk of pathologic root dilatation over time, warranting closer longitudinal follow-up.

Advanced Imaging Technologies for Assessing Tetralogy of Fallot: Insights Into Flow Dynamics

Tetralogy of Fallot is the most common cyanotic congenital heart defect requiring surgical repair. Although surgical interventions have significantly reduced mortality, postrepair complications, such as pulmonary valve regurgitation and stenosis, may lead to adverse outcomes, including right ventricular dysfunction and increased risks of morbidity and mortality. This review explores the potential of advanced imaging technologies, including 4-dimensional-flow magnetic resonance imaging and high-frame-rate echocardiography, in providing valuable insights into blood flow dynamics and energy parameters. Quantitative measures, such as energy loss and vorticity, along with qualitative flow analysis, can provide additional insights into adverse haemodynamics at a potentially earlier and more reversible stage. Furthermore, personalized patient-specific information from these imaging modalities aids in guiding treatment decisions and monitoring postoperative interventions effectively. By characterizing flow patterns, these advanced imaging techniques hold great promise in improving the assessment and management of tetralogy of Fallot, providing tailored insights. However, further research and longitudinal studies are required to fully establish their clinical utility and potential impact on patient care.

Patterns of Aortic Dilation in Tetralogy of Fallot: An Analysis of 100 Fetal Echocardiograms Compared With Matched Controls

Background Although aortic dilation is common in tetralogy of Fallot (TOF), its progression and risk of dissection are not well understood. The mechanism of dilation is primarily attributed to increased flow in utero; an alternative is unequal septation of the truncus arteriosus resulting in a larger aorta and inherently hypoplastic pulmonary artery (PA). If the latter is true, we hypothesize the aorta to PA ratio in TOF is stable throughout gestation, and sums of great artery dimensions are similar to controls. Methods and Results We performed a single-center retrospective study of fetuses with TOF (2014-2020) and matched controls. We compared sums of diameters, circumferences, and cross-sectional areas of the aorta and PA and evaluated the aorta to PA ratio across gestation in 2 TOF subtypes: pulmonary stenosis and atresia (TOF-PA). There were 100 echocardiograms with TOF (36% TOF-PA) with median gestational age of 31 weeks (interquartile range 26.5-34.4) and median maternal age of 34 years (interquartile range 30-37). There were no differences in sums of great artery dimensions between TOF-pulmonary stenosis and controls. In TOF-PA, sums were significantly lower than controls (P values <0.01). The aorta to PA ratio was stable throughout gestation (Pearson's r=0.08 [95% CI, -0.12 to 0.27], -0.06 [95% CI, -0.25 to 0.14]). Conclusions The aorta in fetal TOF is large but grows proportionally throughout gestation, with sums of great artery dimensions similar to controls. TOF-PA appears distinct from TOF-pulmonary stenosis (with smaller sums), warranting further investigation. In conclusion, our findings suggest an intrinsic developmental mechanism contributes to aortic dilation in TOF.

Impaired ascending aortic elasticity in fetuses with tetralogy of Fallot

OBJECTIVES

Aortic wall stiffness has been reported in infants with tetralogy of Fallot (ToF) and may contribute to long-term aortic dilation even after corrective repair surgery. However, little is known about aortic elasticity in fetuses with ToF and the association with neonatal aortic dilation. The objectives of this study were to assess measures of elasticity of the ascending aorta (AAo) in fetuses with ToF and explore the association with neonatal aortic annular dilation in this population.

METHODS

Seventy-six singleton fetuses with ToF and 76 control fetuses of singleton low-risk pregnancies were enroled into this prospective study. Fetal measures of AAo elasticity, including mean longitudinal strain (MLS), global circumferential strain (GCS) and fractional area change (FAC), were assessed by velocity vector imaging. The z-score of the aortic valve (AV) diameter at the level of the annulus, as a measure of aortic annular dilation, was determined in newborns. Logistic regression analysis was used to investigate the association between fetal measures of AAo elasticity and neonatal aortic annular dilation (defined as an AV annular z-score > 2) in cases with ToF identified prenatally.

RESULTS

Median MLS, GCS and FAC in fetuses with ToF were lower than those in normal fetuses (7.52% vs 12.15% for MLS, 22.05% vs 29.73% for GCS and 34.2% vs 48.3% for FAC, all P < 0.001). Aortic annular dilation was present in 53/76 (69.7%) newborns with ToF. After adjustment for gestational age at fetal echocardiography and birth weight, fetal MLS, GCS and FAC were independently associated with aortic annular dilation neonatally, with odds ratios of 0.66, 0.78 and 0.82, respectively (P < 0.05). The best cut-off values of these prenatal measures of AAo elasticity for predicting neonatal aortic annular dilation in fetuses with ToF were 9.02% for MLS, 23.56% for GCS and 37.2% for FAC (P < 0.001), with areas under the receiver-operating-characteristics curves of 0.94, 0.91 and 0.93, respectively.

CONCLUSION

Measures of AAo elasticity are decreased in fetuses with ToF. Impaired AAo elasticity in the fetal period is associated with aortic annular dilation postnatally. Additional research is needed to evaluate the relationship between the AAo elasticity injury pattern and degeneration of AAo elasticity under stress as well as the long-term outcome in this population. © 2022 International Society of Ultrasound in Obstetrics and Gynecology.

Serial Magnetic Resonance Imaging for Aortic Dilation in Tetralogy of Fallot With Pulmonary Stenosis

Aortic dilation occurs in patients with repaired tetralogy of Fallot (TOF), but the rate of growth is incompletely characterized. The aim of this study was to assess the rates of growth of the aortic root and ascending aorta in a cohort of pediatric and adult patients with sequential magnetic resonance angiography Magnetic Resonance Imaging (MRI) data. Using serial MRI data from pediatric and adult patients with repaired TOF, we performed a retrospective analysis of the rates of growth and associations with growth of the aortic root and ascending aorta. Patients with pulmonary atresia or absent pulmonary valve were excluded. Between years 2005 to 2021, a total of 99 patients were enrolled. A follow-up MRI was performed an average of 5.9 ± 3.7 years from the initial study. For the cohort aged ≥16 years, the mean rate of change in diameter was 0.2 ± 0.5 mm/year at the ascending aorta and 0.2 ± 0.6 mm/year at the sinus of Valsalva. For the entire cohort, the mean change in cross-sectional area indexed to height at the ascending aorta was 7 ± 12 mm2/m/year and at the sinus of Valsalva was 10 ± 16 mm2/m/year. Younger age was associated with higher rates of growth of the sinus of Valsalva while the use of β blockers or angiotensin-converting enzyme inhibitors was associated with a slower rate of growth. There were no cases of aortic dissection in this cohort. We conclude that serial MRI demonstrates a slow rate of growth of the aorta in the TOF.

Being Overweight Is Related to Neoaortic Sinus Dilatation After Arterial Switch Operation

Background

Neoaortic sinus dilatation is a late comorbidity after an arterial switch operation in patients with dextro-transposition of the great arteries. We aim to explore whether neoaortic sinus dilatation is related to overweight or obesity, as these affect aortic remodeling in such patients.

Methods

We measured neoaortic diameters including those for the annulus, sinus, sinotubular junction, and ascending aorta by echocardiography and studied the relationship between these diameters and body mass index in patients aged 15 years and older after an arterial switch operation.

Results

A total of 45 patients were studied. Median (interquartile range) age, body mass index, and systolic blood pressure at echocardiography were 20 (17–28) years, 21.2 (18.4–24.2) kg/m2, and 120 (112–127) mm Hg, respectively. Echocardiogram revealed the following median values (interquartile ranges): neoaortic annulus diameter, 22.2 (19.8–23.8) mm; sinus diameter, 34.6 (31.8–39.8) mm; sinotubular junction diameter, 27.5 (22.4–30.0) mm; and ascending aortic diameter, 20.4 (19.4–22.7) mm. The neoaortic sinus diameter was significantly correlated with body mass index (r = 0.41, P = .004) and was significantly larger in patients with concomitant ventricular septal defect (P &lt; .001) and those who were over-weight (body mass index ≥25 kg/m2; P = .006).

Conclusion

Neoaortic sinus dilatation after an arterial switch operation is associated with being overweight during adolescence and young adulthood. It is important to prevent obesity in patients after an arterial switch operation and educate them on a healthy lifestyle.

Spatially Distinct Genetic Determinants of Aortic Dimensions Influence Risks of Aneurysm and Stenosis

BACKGROUND

The left ventricular outflow tract (LVOT) and ascending aorta are spatially complex, with distinct pathologies and embryologic origins. Prior work examined the genetics of thoracic aortic diameter in a single plane.

OBJECTIVES

We sought to elucidate the genetic basis for the diameter of the LVOT, aortic root, and ascending aorta.

METHODS

Using deep learning, we analyzed 2.3 million cardiac magnetic resonance images from 43,317 UK Biobank participants. We computed the diameters of the LVOT, the aortic root, and at 6 locations of ascending aorta. For each diameter, we conducted a genome-wide association study and generated a polygenic score. Finally, we investigated associations between these scores and disease incidence.

RESULTS

A total of 79 loci were significantly associated with at least 1 diameter. Of these, 35 were novel, and most were associated with 1 or 2 diameters. A polygenic score of aortic diameter approximately 13 mm from the sinotubular junction most strongly predicted thoracic aortic aneurysm (n = 427,016; mean HR: 1.42 per SD; 95% CI: 1.34-1.50; P = 6.67 × 10-21). A polygenic score predicting a smaller aortic root was predictive of aortic stenosis (n = 426,502; mean HR: 1.08 per SD; 95% CI: 1.03-1.12; P = 5 × 10-6).

CONCLUSIONS

We detected distinct genetic loci underpinning the diameters of the LVOT, aortic root, and at several segments of ascending aorta. We spatially defined a region of aorta whose genetics may be most relevant to predicting thoracic aortic aneurysm. We further described a genetic signature that may predispose to aortic stenosis. Understanding genetic contributions to proximal aortic diameter may enable identification of individuals at risk for aortic disease and facilitate prioritization of therapeutic targets.

Valve-sparing aortic root replacement in adult patients with congenital heart disease

OBJECTIVES

Aortic root dilatation is frequently observed in patients with congenital heart defects (CHD), but has received little attention in terms of developing a best practice approach for treatment. In this study, we analysed our experience with aortic valve-sparing root replacement in patients following previous operations to repair CHD.

METHODS

In this study, we included 7 patients with a history of previous surgery for CHD who underwent aortic valve-sparing operations. The underlying initial defects were tetralogy of Fallot (n = 3), transposition of great arteries (n = 2), coarctation of the aorta (n = 1), and pulmonary atresia with ventricle septum defect (n = 1). The patients' age ranged from 20 to 40 years (mean age 31 ± 6 years).

RESULTS

David reimplantation was performed in 6 patients and a Yacoub remodelling procedure was performed in 1 patient. Four patients underwent simultaneous pulmonary valve replacement. The mean interval between the corrective procedure for CHD and the aortic valve-sparing surgery was 26 ± 3 years. There was no operative or late mortality. The patient with transposition of great arteries following an arterial switch operation was re-operated 25 months after the valve-sparing procedure due to severe aortic regurgitation. In all other patients, the aortic valve regurgitation was mild or negligible at the latest follow-up (mean 8.7 years, range 2.1-15.1 years).

CONCLUSIONS

Valve-sparing aortic root replacement resulted in good aortic valve function during the first decade of observation in 6 of 7 patients. This approach can offer a viable alternative to root replacement with mechanical or biological prostheses in selected patients following CHD repair.

Alternative to body surface area as a solution to correct systematic bias in pediatric echocardiography Z scores

BACKGROUND

Z scores are the method of choice to report dimensions in pediatric echocardiography. Z scores based on body surface area (BSA) have been shown to cause systematic biases in overweight and obese children. Using aortic valve (AoV) diameters as a paradigm, the aims of this study were to assess the magnitude of Z score underestimation in children with increased body mass index Z score (BMI-Z) and to determine if a predicting model with height and weight as independent predictors would minimize this bias.

METHODS

In this multicenter, retrospective, cross-sectional study, 15,006 normal echocardiograms in healthy children 1-18 years old were analyzed. Residual associations with body size were assessed for previously published Z score. BSA-based and alternative prediction models based on height and weight were developed and validated in separate training and validation samples.

RESULTS

Existing BSA-based Z scores incompletely adjusted for weight, BSA and BMI-Z and led to an underestimation of >0.8 Z score units in subjects with higher BMI-Z, compared to lean subjects. BSA-based models led to overestimation of predicted AoV diameters with increasing weight or BMI-Z. Models using height and weight as independent predictors improved adjustment with body size, including in children with higher BMI-Z.

CONCLUSIONS

BSA-based models result in underestimation of Z scores in patients with high BMI-Z. Prediction models using height and weight as independent predictors minimize residual associations with body size and generate well-fitted predicted values that could apply to all children, including those with low or high BMI-Z.

Follow-up aortic dilatation in patients with repaired tetralogy of Fallot using cardiovascular magnetic resonance

Purpose

The study sought to determine the rate of aortic expansion and correlation with somatic growth in patients with repaired tetralogy of Fallot (rTOF), and predictors for determining the annual growth rate of the aorta (Ao-AGR).

Methods

Ninety-four rTOF patients (mean age 14.5 ± 4.4 years) with two cardiac magnetic resonance tests (CMR) (median duration 52 months, interquartile range, IQR 24-71) were analyzed for aortic diameter (AoD) at the annulus, the sinus of Valsalva (SoV), the sinotubular junction, and the ascending aorta (AAo), and compared with the normal limit AoD (NL-AoD) values. The median age-at-repair was 60 months (IQR 36-84). Ao-AGR and its index (Ao-AGRI) were derived from changes of the AoD and AoD-index, respectively, divided by the duration between the two studies. Three potential predictors (baseline AoD, sex, and age-at-repair) for the progression of Ao-AGR were analyzed.

Results

There was a significant larger AoD than NL-AoD (p < 0.001). Slow aortic growth was encountered in 78-85 % of patients. The Ao-AGR was slow, the median AGR ranged from 0.37 mm (IQR 0.13-0.72) at annulus to 0.56 mm (IQR 0.22-0.91) at AAo. There was a regression in Ao-AGRI, ranged from -1.41 mm (IQR -1.94, -0.87) at annulus to -2.36 mm (IQR -3.09, -1.63) at SoV. The three predictors were not correlated with severity of Ao-AGR.

Conclusion

Most adolescents with rTOF show significant aortic dilatation. There is a slow Ao-AGR with regression of Ao-AGRI, which may suggest that the rate of aortic growth is slower than the somatic growth. There are no significant predictors of the progression of Ao-AGR.

Magnetic resonance imaging assessment of aortic dilatation and distensibility in 269 patients with repaired tetralogy of Fallot

PURPOSE

To determine the prevalence and degree of aortic dilatation (A_dilatation), severity of aortic stiffness (A_stiff), factors for A_dilatation, and level of aortic root most sensitive to A_stiff in patients with repaired tetralogy of Fallot (rTOF).

MATERIALS AND METHODS

269 patients with rTOF (mean age 14.9 ± standard deviation 5.0 years) were analyzed for A_dilatation at annulus, sinus, sinotubular junction, and ascending aorta (aAo). Aortic size index was graded as Z score < 2, 2-2.99, 3-4.99 and ≥ 5. Aortic distensibility (aA_dis) was categorized according to 4 aortic levels and dilatation severity. Factors for A_dilatation and level of aortic root most sensitive to A_stiff were analyzed.

RESULTS

Sinus and aAo were the two most common sites of A_dilatation, with a prevalence of 84% and 76%, respectively. A decreased aA_dis was found (mean 5.38 ± 1.79 10^-3 mmHg^-1). aA_dis only declined significantly at the sinus level (p = 0.009). Male sex, age-at-repair and aortic regurgitation were significant factors for A_dilatation, with male sex as the strongest factor (odds ratio 2.94). There was a significant decline in aA_dis at sinus level (p = 0.002) as A_dilatation progressed.

CONCLUSIONS

We observed a high prevalence of A_dilatation and A_stiff in patients with rTOF. Male sex is the strongest factor for A_dilatation. The sinus is the most sensitive area for determining a negative aA_dis effect.

[The adult with tetralogy of fallot: what the clinical cardiologist needs to know]

Tetralogy of Fallot (TOF) is the most common cyanotic congenital heart disease. After more than seven decades of the first palliative surgery, TOF prognosis has changed dramatically. The prevalence of TOF is approximately 3 per 10 000 births, representing 7 to 10% of congenital heart disease. With a higher survival into adulthood, the clinical cardiologist faces challenges in the management of this population, from severe pulmonary regurgitation to heart failure and ventricular arrhythmias. Its prevalence is approximately 3 per 10 000 live births, representing 7 to 10% of congenital heart disease. This review will describe the most relevant aspects of the care of adult patients with this disease.

Aortopathy in Congenital Heart Disease

Aortic dilatation is common in patients with congenital heart disease and is seen in patients with bicuspid aortic valve and those with conotruncal congenital heart defects. It is important to identify patients with bicuspid aortic valve at high risk for aortic dissection. High-risk patients include those with the aortic root phenotype and those with syndromic or familial aortopathies including Marfan syndrome, Loeys-Dietz syndrome, and Turner syndrome. Aortic dilatation is common in patients with conotruncal congenital heart defects and rarely results in aortic dissection.

Long-Term Risk Factors for Dilatation of the Proximal Aorta in a Large Cohort of Children With Bicuspid Aortic Valve

Background:

Patients with bicuspid aortic valve (BAV) have a higher risk of developing aortic valve dysfunction and progressive proximal aorta dilatation, which can lead to aortic dissection. To this day, identification of children at risk of developing severe aortic dilatation during their pediatric follow-up is still challenging because most studies were restricted to adult subjects. The overarching goal of this study was to identify risk factors of aortic dilatation in children with BAV.

Methods:

We extracted clinical and echocardiographic data of all BAV subjects aged 0 to 20 years followed at Centre Hospitalier Universitaire Sainte-Justine between 1999 and 2016. We excluded subjects with concomitant heart defects and conditions affecting proximal aorta dimensions. Proximal aorta diameters (expressed as Z scores) were modeled in relation to age and potential predictive variables in a linear mixed model. The primary outcome was the rate of dilatation.

Results:

We included 761 subjects (3134 echocardiograms) in final analyses. The mean ascending aorta Z score progression rate for BAV patient with a normally functioning aortic valve was estimated at 0.05 Z score unit per year. The strongest predictors of an increased dilatation rate were severe aortic stenosis, moderate and severe aortic regurgitation, and uncorrected coarctation of the aorta. Aortic valve leaflet fusion pattern and sex were not associated with progression rate.

Conclusions:

Children with a normally functioning BAV exhibited a very slow proximal aorta dilatation rate. Ascending aorta dilatation rate was significantly increased in patients with more than mild aortic valve dysfunction but was independent from BAV leaflet fusion type.