Role of fibrillin-1 genetic mutations and polymorphism in aortic dilatation in patients undergoing intracardiac repair of tetralogy of Fallot

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.

Prevalence and risk of progressive aortic aneurysm and dissection in adults with conotruncal anomalies

AIMS

Conotruncal anomalies share common embryogenic defects of the outflow tracts and great arteries, which result in a predisposition to aortic aneurysms. The purpose of this study was to describe the prevalence and risk of progressive aortic aneurysms in adults with conotruncal anomalies.

METHODS AND RESULTS

Retrospective study of adults with conotruncal anomalies that underwent cross-sectional imaging 2003-20. Aneurysm was defined as aortic root/mid-ascending aorta >2.1 mm/m2/>1.9 mm/m2, progressive aneurysm as increase by >2 mm, and severe aneurysm as dimension >50 mm. Of 2261 patients (38 ± 12 years; male 58%), 1167 (52%) had an aortic aneurysm, and 205 (14%) had a severe aortic aneurysm. Mean annual increase in aortic root/mid-ascending aorta was 0.3 ± 0.1 mm/0.2 ± 0.1 mm. The 3-, 5-, and 7-year cumulative incidence of the progressive aortic aneurysm was 4%, 7%, and 9%, respectively. The rate of aneurysm growth decreased with age, with no significant growth after age 40 years. There was an excellent correlation between aortic indices from cross-sectional imaging and echocardiography. Of 950 females, 184 had ≥1 pregnancy, and 81 (44%) of the 184 patients had aortic aneurysm prior to pregnancy. There was no aortic dissection or progression of the aortic aneurysm during pregnancy. Overall, there was no aortic dissection during 7984 patient-years of follow-up.

CONCLUSIONS

Aortic aneurysm was common in patients with conotruncal anomalies. However, the risk of progressive aneurysm or dissection was low. Collectively, these data suggest a benign natural history and perhaps a less frequent need for cross-sectional imaging. Further studies are required to determine the optimal timing for surgical intervention in this population.

Histologic Abnormalities of the Ascending Aorta: Effects on Aortic Remodeling after Intracardiac Repair of Tetralogy of Fallot

We evaluated aortic tissue specimens from patients undergoing tetralogy of Fallot repair, to determine whether histologic abnormalities affect postsurgical aortic remodeling and other patient-related variables. Using light microscopy, we studied full-thickness aortic wall tissue operatively excised from 118 consecutive patients undergoing intracardiac repair of tetralogy of Fallot. We performed multiple linear regression analysis to identify independent predictors of change in aortic root dimensions, which we measured with echocardiography after repair and every 3 months thereafter. Thirty histologically normal specimens were used as controls. Elastic fiber fragmentation was found in 74.6% of the abnormal specimens, mucoid extracellular matrix accumulation in 49.2%, smooth muscle cell nuclei loss in 39%, smooth muscle cell disorganization in 28.8%, and medial fibrosis in 52.5%. At a mean follow-up time of 83.55 ± 42.08 months, mean aortic sinotubular diameter decreased from 28.79 ± 9.15 to 27.16 ± 8.52 mm/m2 (r =-0.43; P <0.001). Aortic sinotubular diameter decreased by 0.6 mm/m2 among females (β =0.6, SE=0.31; P =0.05) and by 0.88 mm/m2 in patients who had elastic fiber fragmentation or loss (β =0.88, SE=0.38; P =0.02). In bivariate and multiple linear regression analysis, duration of follow-up emerged as an independent predictor of aortic remodeling. The aortic histopathologic changes in our patients had an independent negative impact on the degree of aortic remodeling after surgery. We observed the most improved aortic sinotubular diameter in patients who had either histologically normal aortas or aortas with elastic fragmentation.

Weak Ligaments and Sloping Joints: A New Hypothesis for Development of Congenital Atlantoaxial Dislocation and Basilar Invagination

OBJECTIVE

Developmental bony craniovertebral junction (CVJ) anomalies seem to have a genetic basis and also abnormal joint morphology causing atlantoaxial dislocation (AAD) and basilar invagination (BI).

METHODS

DNA extracted polymerase chain reaction single-stranded conformation polymorphism (SSCP) performed for mutation screening of FBN1 gene (n = 50 cases+ 50 age/sex-matched normal; total: 100). Samples with a deviated pattern of bands in SSCP were sequenced to detect the type of variation. Computed tomography (CT) scans of 100 patients (15-45 years old) compared with an equal number of age/sex-matched controls (21.9 ± 8.2 years). Joint parameters studied: sagittal joint inclination (SI), craniocervical tilt (CCT), coronal joint inclination (CI).

RESULTS

Thirty-nine samples (78%) showed sequence variants. Exon 25, 26, 27, and 28 showed variable patterns of DNA bands in SSCP, which on sequencing gives various types of DNA sequence variations in intronic region of the FBN1 gene in 14%, 14%, 6%, and 44% respectively. CT radiology:SI and CCT correlated with both BI and AAD (p < 0.01). The mean SI value in controls: 83.35° ± 8.65°, and in patients with BI and AAD:129° ± 24.05°. Mean CCT in controls: 60.2° ± 9.2°, and in patients with BI and AAD: 86.0° ± 18.1°. Mean CI in controls:110.3° ± 4.23°, and in cases: 125.15° ± 16.4°.

CONCLUSION

The study showed mutations in FBN1 gene (reported in Marfan syndrome). There is also an alteration of joint morphology, correlating with AAD and BI severity. Hence, we propose a double-hit hypothesis: the presence of weak ligaments (due to FB1 gene alterations) and abnormal joint morphology may contribute to AAD and BI.

Primary and secondary aortopathy associated with adult congenital heart disease - retrospective study

Background

Primary and secondary aortopathy are frequently encountered in patients with congenital heart disease. The aim of this study is to present our experience and the incidence of primary and secondary adult CHD-associated aortopathy.

Methods

The cohort is comprised of adult patients with congenital heart disease from the registry of the Eastern Slovakia Institute of Cardiovascular Diseases. Data from the last follow-up examinations are included in this study. In the primary and secondary aortopathy groups were 35 and 12 patients respectively. As a control group were selected 64 patients with non aortopathy associated congenital heart disease (atrial and ventricular septal defect).

Results

Patients with primary and secondary aortopathy had larger ascending aorta/aortic root diameters than the control group (36.28 (26–49) mm vs 30.25 (21–41) mm p = 0.000113, 33.82 27–49) mm vs 29.03 (19–38)mm p = 0.000366 and 42.1 (30–50) mm vs 30.25 (21–41) mm, p = 0.000106, 35.67 (27–48) mm vs 29.03 (19–38) mm, p = 0.000119 respectively). Moreover, patients with secondary aortopathy had statistically significant larger ascending aorta diameter compared to the patients with primary aortopathy (42.1 (30–50) mm vs 36.28 (26–49) mm p = 0.030). During the follow-up period, were performed only in 2 patients (one from each group) operations on the aortic root and the ascending aorta due to aortic root or ascending aorta dilatation.

Conclusion

More patients with secondary aortopathy had dilated ascending aorta/ aortic root, as well as larger aortic diameters compare to the patients with primary aortopathy. Routine follow-up of these patients with attention to aortic diameter is necessary.

Bentall's Procedure for Annuloaortic Ectasia and Severe Aortic Regurgitation in a Patient With Repaired Tetralogy of Fallot and Aortic Valvular Reconstruction

A 21-year-old female patient with repaired tetralogy of Fallot and aortic valvular reconstruction with aneurysmal aortic root and severe aortic regurgitation underwent aortic root replacement. Intrinsic aortopathy in tetralogy of Fallot and its surgical importance are highlighted.

Surgical Outcomes in Syndromic Tetralogy of Fallot: A Systematic Review and Evidence Quality Assessment

Tetralogy of Fallot (ToF) is one of the most common cyanotic congenital heart defects. We sought to summarize all available data regarding the epidemiology and perioperative outcomes of syndromic ToF patients. A PRISMA-compliant systematic literature review of PubMed and Cochrane Library was performed. Twelve original studies were included. The incidence of syndromic ToF was 15.3% (n = 549/3597). The most prevalent genetic syndromes were 22q11.2 deletion (47.8%; 95% CI 43.4-52.2) and trisomy 21 (41.9%; 95% CI 37.7-46.3). Complete surgical repair was performed in 75.2% of the patients (n = 161/214; 95% CI 69.0-80.1) and staged repair in 24.8% (n = 53/214; 95 CI 19.4-30.9). Relief of RVOT obstruction was performed with transannular patch in 64.7% (n = 79/122; 95% CI 55.9-72.7) of the patients, pulmonary valve-sparing technique in 17.2% (n = 21/122; 95% CI 11.5-24.9), and RV-PA conduit in 18.0% (n = 22/122; 95% CI 12.1-25.9). Pleural effusions were the most common postoperative complications (n = 28/549; 5.1%; 95% CI 3.5-7.3). Reoperations were performed in 4.4% (n = 24/549; 95% CI 2.9-6.4) of the patients. All-cause mortality rate was 9.8% (n = 51/521; 95% CI 7.5-12.7). Genetic syndromes are seen in approximately 15% of ToF patients. Long-term survival exceeds 90%, suggesting that surgical management should be dictated by anatomy regardless of genetics.

Aortopathy in tetralogy of Fallot-a collective review

The pathophysiology of aortic diseases in Tetralogy of Fallot has been analyzed in various studies, focusing on the histopathology of the aortic root, altered hemodynamics, and effect of early corrective repair on the incidence of aortic root dilatation. In this review article, we sought to integrate these studies for a better understanding of the natural history and practical implications of aortic root dilatation in Tetralogy of Fallot. This better equips us to appropriately implement potentially effective interventions.

Cross-sectional Areas of the Thoracic Aorta in Children and Adolescents With Repaired Tetralogy of Fallot Obtained by Cardiac Magnetic Resonance Angiography

PURPOSE

Dilatation of the thoracic aorta is a well-known finding in corrected Tetralogy of Fallot. Complications are rare but can be life-threatening. Standard 1-dimensional (1D) measurements have several limitations. We sought to establish contrast-enhanced magnetic resonance angiography cross-sectional areas of the aorta that could serve as reference values and to identify parameters that are associated with aortic dilatation.

MATERIALS AND METHODS

We enrolled 101 children and adolescents. The aortic areas were measured at the level of the aortic sinus (AS), the sinotubular junction (STJ), the ascending aorta (AA), the brachiocephalic trunk (TBC), and the descending aorta (DA). Sex-specific aortic dimensions were presented as percentile curves as well as regression equations. Furthermore volumetric and functional parameters as well as clinical data were analyzed to identify parameters that are associated with aortic dilatation.

RESULTS

Aortic areas (mm) for female subjects were 139+366×body surface area (BSA) for the AS, 134+255×BSA for the STJ, 113+239×BSA for the AA, 88+185×BSA proximal to the TBC, and 2.9+88×BSA for the DA. Aortic areas (mm) for male subjects were 162+403×BSA for the AS, 171+258×BSA for the STJ, 151+233×BSA for the AA, 73+206×BSA proximal to the TBC, and 21+80×BSA for the DA. The postoperative interval and age at examination were parameters associated with aortic size.

CONCLUSIONS

We provide aortic areas in children and adolescents after correction of Tetralogy of Fallot measured by contrast-enhanced magnetic resonance angiography. Our 2D data may better depict the geometry of enlarged aortae than standard 1D diameters and serve as reference values for evaluating aortic disease in these patients.

Landmark lecture: Perloff lecture: Tribute to Professor Joseph Kayle Perloff and lessons learned from him: aortopathy in adults with CHD

Marfan syndrome, bicuspid aortic valve, and/or coarctation of the aorta are associated with medial abnormalities of the ascending aortic or para-coarctation aorta. Medial abnormalities in the ascending aorta are prevalent in other type of patients with a variety of CHDs such as single ventricle, persistent truncus arteriosus, transposition of the great arteries, hypoplastic left heart syndrome, and tetralogy of Fallot, encompassing a wide age range and may predispose to dilatation, aneurysm, and rapture necessitating aortic valve and root surgery. These CHDs exhibit ongoing dilatation of the aortic root and reduced aortic elasticity and increased aortic stiffness that may relate to intrinsic properties of the aortic root. These aortic dilatation and increased stiffness can induce aortic aneurysm, rapture of the aorta, and aortic regurgitation, but also provoke left ventricular hypertrophy, reduced coronary artery flow, and left ventricular failure. Therefore, a new clinical entity can be used to call this association of aortic pathophysiological abnormality, aortic dilation, and aorto-left ventricular interaction - "aortopathy".

Diagnosis and Management of Noncardiac Complications in Adults With Congenital Heart Disease: A Scientific Statement From the American Heart Association

Life expectancy and quality of life for those born with congenital heart disease (CHD) have greatly improved over the past 3 decades. While representing a great advance for these patients, who have been able to move from childhood to successful adult lives in increasing numbers, this development has resulted in an epidemiological shift and a generation of patients who are at risk of developing chronic multisystem disease in adulthood. Noncardiac complications significantly contribute to the morbidity and mortality of adults with CHD. Reduced survival has been documented in patients with CHD with renal dysfunction, restrictive lung disease, anemia, and cirrhosis. Furthermore, as this population ages, atherosclerotic cardiovascular disease and its risk factors are becoming increasingly prevalent. Disorders of psychosocial and cognitive development are key factors affecting the quality of life of these individuals. It is incumbent on physicians who care for patients with CHD to be mindful of the effects that disease of organs other than the heart may have on the well-being of adults with CHD. Further research is needed to understand how these noncardiac complications may affect the long-term outcome in these patients and what modifiable factors can be targeted for preventive intervention.

A Comparative Study of Histopathological Changes in the Ascending Aorta and the Risk Factors Related to Histopathological Conditions and Aortic Dilatation in Patients With Tetralogy of Fallot and a Functionally Univentricular Heart

BACKGROUND

The purposes of this study were to prospectively evaluate the histologic characteristics of the aortic wall of patients undergoing univentricular type of repair and compare the same with the findings observed in patients undergoing intracardiac repair of tetralogy of Fallot (TOF).

PATIENTS AND METHODS

Operatively excised full-thickness aortic wall tissue from 99 consecutive patients undergoing either intracardiac repair of TOF (group I; n=42) or univentricular repair (group II; n=57) were studied by light microscopy. Age at operation was 13 months to 28 years (mean 99.97±73.21months) for group I and 9 months to 25 years (mean 79.52±60.09) months for group II patients.

RESULTS

Dilatation of the ascending aorta was present in 85.7% patients with TOF and 91.2% patients with a univentricular heart. Seventeen (17.2%) aortic specimens were histologically normal and were used as normal controls (group I, n=5; group II, n=12). A lamellar count of less than 60 was associated with a sensitivity of 97.2% and a specificity of 66.7% in patients undergoing repair of TOF and a sensitivity of 84.6% and a specificity of 80% in patients undergoing univentricular type of repairs respectively. Patients undergoing intracardiac repair of TOF and those undergoing univentricular repair exhibited 23.67 times (15.91-147.40) and 8.48 times (3.62-15.84) increased risk of aortic dilatation respectively.

CONCLUSIONS

Our findings indicate the existence of significant elastic fragmentation, muscle disarray, medionecrosis and fibrosis involving the ascending aortic media in patients with a functionally univentricular heart and dilated aorta. These histopathological changes are similar to those encountered in patients with TOF and dilated aorta.

Molecular and Genetic Insights into Thoracic Aortic Dilation in Conotruncal Heart Defects

Thoracic aortic dilation (AD) has commonly been described in conotruncal defects (CTDs), such as tetralogy of Fallot, double outlet right ventricle and transposition of the great arteries, and truncus arteriosus. Several theories for this have been devised, but fairly recent data indicate that there is likely an underlying histologic abnormality, similar to that seen in Marfan and other connective tissue disease. The majority of aortic dissection in the general population occurs after the age of 45 years, and there have been very few case reports of aortic dissection in CTD. Given advances in cardiac surgery and increasing survival over the past several decades, there has been rising concern that, as patients who have survived surgical correction of these defects age, there may be increased morbidity and mortality due to aortic dissection and aortic regurgitation. This review discusses the most recent developments in research into AD in CTD, including associated genetic mutations.

Mechanism of aortic root dilation and cardiovascular function in tetralogy of Fallot

The aortic root dilation in tetralogy of Fallot (TOF) is a long-term clinical problem, because a severely dilated aorta can lead to aortic regurgitation, dissection, or rupture, which can be fatal, necessitating surgical intervention. The details of the mechanism of aortic root dilation, however, are unclear. We have shown that aortic stiffness is increased in patients with repaired TOF, and may mirror the histological abnormality of elastic fiber disruption and matrix expansion. This aortic stiffness is related closely to the aortic dilation, indicating that aortic stiffness may be a predictor of outcome of aortic dilation. Furthermore, the aortic volume overload is a very important determinant of aortic diameter in TOF patients before corrective surgery. In addition, a chromosomal abnormality and the transforming growth factor-β signaling pathway, a major contributor to aortic dilation in Marfan syndrome, also affect this mechanism. In this way, aortic dilation in TOF patients is suggested to be a multifactorial disorder. The aim of this review was therefore to clarify the mechanism of aortic dilation in TOF, focusing on recent research findings. Studies linking histopathology, mechanical properties, molecular/cellular physiology, and clinical manifestations of aortic dilation facilitate appropriate treatment intervention and improvement of long-term prognosis of TOF.

Aortopathy associated with congenital heart disease: A current literature review

In patients born with congenital heart disease, dilatation of the aorta is a frequent feature at presentation and during follow-up after surgical intervention. This review provides an overview of the pathologies associated with aortopathy, and discusses the current knowledge on pathophysiology, evolution, and treatment guidelines of the aortic disease associated with congenital heart defects.

Analysis of the aortic root in patients with tetralogy of Fallot undergoing early repair: form follows function

OBJECTIVE

Aortic root dilatation remains of concern late after repair for tetralogy of Fallot (ToF). We have previously demonstrated that the aortic root size decreases progressively after early correction. To test whether the aortic wall changes are intrinsic or acquired, a histologic study was performed of infants at early repair.

METHODS

From 24 of 31 infants undergoing ToF repair (mean age, 5.9±4.9 months), ascending aortic biopsies were obtained. After conventional staining, the specimens were given a histologic score (0-3) for medionecrosis, ground substance accumulation, fibrosis, smooth muscle cell disarray, and apoptosis. The aortic root diameters were monitored using echocardiography for ≤2 years postoperatively.

RESULTS

Nearly one half of the specimens showed signs of fibrosis (45%), with increased mucoid accumulation in 15% and elastin fragmentation in 5%. The aortic root was dilated in all infants at operation (mean indexed diameter-annulus, 38.1±5.8; sinus, 47.8±6; sinotubular junction, 38.7±5.4 mm/m2) and had regressed significantly within 2 years (mean indexed diameter-annulus, 27.9±4.7; sinus, 36.4±5.1; sinotubular junction, 30.4±6 mm/m2; P<.0001). The total histology score showed no correlation with indexed diameter regression at 2 years.

CONCLUSIONS

Infants with ToF undergoing repair around 6 months old already had limited features of aortic wall degradation at surgery. Echocardiographic follow-up, however, demonstrated significant reductions in the indexed aortic diameters. We presume that early repair of ToF will prevent a disproportionate aortic diameter increase by halting progression of the limited histologic changes potentially predisposing to late aortic dilatation.

Aortopathy in Congenital Heart Disease in Adults: Aortic Dilatation with Decreased Aortic Elasticity that Impacts Negatively on Left Ventricular Function

Bicuspid aortic valve and/or coarctation of the aorta are consistently associated with ascending aortic and para-coarctation medial abnormalities. Medial abnormalities in the ascending aorta are prevalent in other types of patients with a variety of forms congenital heart disease (CHD), such as single ventricle, persistent truncus arteriosus, transposition of the great arteries, hypoplastic left heart syndrome, tetralogy of Fallot. These abnormalities encompass a wide age range, and may predispose to dilatation, aneurysm, and rupture that necessitates aortic valve and root surgery. This dilatation can develop in CHD patients without stenotic region. These CHDs exhibit ongoing dilatation of the aortic root and reduced aortic elasticity and increased aortic stiffness that may relate to intrinsic properties of the aortic root. The concept of aortic dilatation is shifting a paradigm of aortic dilatation, as so called post stenotic dilatation, to primary intrinsic aortopahy. These aortic dilatation and increased stiffness can induce aortic aneurysm, rupture of the aorta and aortic regurgitation, but also provoke left ventricular hypertrophy, reduced coronary artery flow and left ventricular failure. We can recognize this association of aortic pathophysiological abnormality, aortic dilation and aorto-left ventricular interaction as a new clinical entity: "aortopathy".

Structural abnormalities of the pulmonary trunk in tetralogy of Fallot and potential clinical implications: a morphological study

OBJECTIVES

The purpose of this study was to determine whether intrinsic histological abnormalities of the pulmonary trunk (PT) are present from birth and interact with palliative surgery and/or repair.

BACKGROUND

Little is known about PT histology in patients with tetralogy of Fallot (TOF), especially in the era of surgical intervention in childhood.

METHODS

We studied 39 formalin-fixed necropsy heart specimens with TOF and compared them with 17 normal control heart specimens. Sections of the PT and aorta were studied by light microscopy using various stains; histological findings were graded according to severity.

RESULTS

Among the TOF group (1 fetus, 11 infants, 14 children, and 13 adults), 11 patients had undergone palliative and 10 patients had undergone reparative surgery at a median age of 8 years (range 2.5 to 18 years). Histological changes of grade 2 or higher were present in 59% (medionecrosis), 36% (fibrosis), 56% (cystlike formation), and 56% (abnormal elastic tissue configuration) of TOF patients. Total histology grading scores were higher in TOF hearts (median 6, range 1 to 9) compared with controls (median 1, range 0 to 6; p < 0.0001). Histological abnormalities were present among infants (median score 3.5, range 1 to 9) and after palliative surgery (median score 5, range 2 to 9) or repair (median score 7.5, range 4 to 9).

CONCLUSIONS

Marked histological abnormalities in the PT of hearts with TOF exist compared with controls. These changes were present from infancy and among patients who had undergone palliative or reparative surgery, although operations in this cohort were performed late. Our data suggest that structural abnormalities of the PT, similar to these recently shown in the aorta, are intrinsic.