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

Conotruncal Heart Defects: A Narrative Review of Molecular Genetics, Genomics Research and Innovation

Congenital heart defects (CHDs) are most prevalent cardiac defects that occur at birth, leading to significant neonatal mortality and morbidity, especially in the developing nations. Among the CHDs, conotruncal heart defects (CTDs) are particularly noteworthy, comprising a significant portion of congenital cardiac anomalies. While advances in imaging and surgical techniques have improved the diagnosis, prognosis, and management of CTDs, their molecular genetics and genomic substrates remain incompletely understood. This expert review covers the recent advances from January 2016 onward and examines the complexities surrounding the genetic etiologies, prevalence, embryology, diagnosis, and clinical management of CTDs. We also emphasize the known copy number variants and single nucleotide variants associated with CTDs, along with the current planetary health research efforts aimed at CTDs in large cohort studies. In all, this comprehensive narrative review of molecular genetics and genomics research and innovation on CTDs draws from and highlights selected works from around the world and offers new ideas for advances in CTD diagnosis, precision medicine interventions, and accurate assessment of prognosis and recurrence risks.

Aortic Dissection in a Young Patient With Unsuspected Aortopathy

Aortic dissection is often a fatal condition if not recognized and treated emergently. Fortunately, it is extremely rare in children and adolescents. We report a case of an adolescent boy who survived an aortic dissection due to severe aortic root dilation. A comprehensive history and physical examination, including family history, can facilitate an early diagnosis of connective tissue diseases, such as Loeys-Dietz syndrome (LDS).

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.

Left ventricular strains correlate with aortic elastic properties in adult patients with corrected tetralogy of Fallot (Results from the CSONGRAD Registry and MAGYAR-Path Study)

Background

Aortopathy is a common phenomenon in tetralogy of Fallot (TOF). The current study was designed to detect left ventricular (LV) deformation abnormalities and its relation to aortic stiffness in corrected TOF (cTOF) using the novel three-dimensional (3D) speckle-tracking echocardiography (3DSTE). Detailed comparative analysis between patients with early palliation-late correction (pcTOF) and early total reconstruction (etrTOF) was also performed.

Methods

The present study consisted of 28 cTOF patients (35.0±15.7 years, 11 males) from which 15 and 13 proved to be pcTOF and etrTOF, respectively. Their clinical parameters were compared to those of 39 matched healthy adults (35.5±6.0 years, 16 males).

Results

cTOF patients showed significantly lower global LV longitudinal, circumferential and area strains as compared to controls. In etrTOF patients, global LV 3D strain was higher than in controls. In pcTOF patients, all LV strains proved to be significantly lower as compared to those of etrTOF patients and controls. In all cTOF patients, several moderate correlations could be detected between LV strain parameters and aortic elastic properties.

Conclusions

Significant LV deformational abnormalities could be demonstrated in cTOF patients. etrTOF patients have beneficial LV strain parameters as compared to those of pcTOF patients. LV strains show correlations with aortic elastic properties.

Provision of medical health care for adults with congenital heart disease associated with aortic involvement

Background

All patients with congenital heart disease (CHD) are chronically ill from their cardiac disease. Despite the increasing evidence that aortic alterations are becoming relevant, the importance of aortopathy in CHD has long been underestimated. This study was conducted to determine the health status of patients and/or the provision of health services of adults with CHD (ACHD) with manifest aortopathy or at risk thereof.

Methods

In a questionnaire-based cross-sectional survey, the "real life"-care of ACHD was analysed, comparing patients with risk of developing aortopathy and/or manifest aortopathy.

Results

Of the 563 enrolled ACHD (49.6% female, mean age 35.8±12.1, 18-86 years) 56.8% (n=320) had a risk of developing aortopathy and/or manifest aortopathy. Of the 320 patients at risk, 187 (33.2% of the total number) had a proven aortopathy. Within this subgroup, the basic medical care for CHD-independent medical problems was given by primary medical care providers [family doctors/general practitioners (GP) in 89.4% (n=286), internists in 13.4% (n=43), physicians of another specialty in 2.5% (n=8)]. Almost all primary medical care providers knew about the CHD of their patients. Even for CHD-specific health problems, the basic medical care of risk patients was provided by a family doctor or GP in 56.6% (n=181) and by an internist in 18.4% (n=59). 30.0% (n=96) primarily consulted another specialist, including cardiologists. Only 32.8% of ACHD at risk had ever been referred to a CHD specialist by a GP for cardiac problems related to their CHD. In contrast, the need for advice was high for ACHD with aortopathy and related mainly to physical activity, employment and education, pregnancy, rehabilitation or health and life insurance. Only 35.5% of patients at risk indicated that their information on specific care structures for ACHD was sufficient, and a further 38.1% of patients were aware of patient organizations.

Conclusions

Even today, aortic involvement in ACHD is an often-overlooked condition, although considerable negative effects on morbidity and mortality exist. As aortopathy gains in importance with increasing age and complexity of CHD, almost all affected ACHD need lifelong medical advice and access to modern, scientifically based care concepts. According to the study-results, primary care providers and also patients are mostly insufficiently informed about the specialized ACHD facilities. The future goal is therefore to create a better awareness of CHD problems among both primary care physicians and the patients concerned.

Metabolic syndrome and coronary artery disease in adults with congenital heart disease

In adults with congenital heart disease (ACHD), conditions acquired with aging, such as metabolic syndrome, hypertension, diabetes mellitus, and obesity, can negatively influence the original cardiovascular disease. Metabolic syndrome has a higher prevalence in ACHD than in the general population. In contrast, coronary artery disease shows a similar prevalence in adults with acyanotic CHD and the general population, while adults with cyanotic CHD, even after repair, have an even lower incidence of coronary artery disease than the general population/adults with acyanotic CHD. However, even in those with cyanotic CHD, coronary artery disease can develop when they have risk factors such as obesity, dyslipidemia, hypertension, diabetes mellitus, smoking habit, or limited exercise. The prevalence of risk factors for cardiovascular disease is similar between ACHD and the general population, but an increased risk of coronary atherosclerosis has been observed for congenital coronary artery anomalies, dextro-transposition of the great arteries after arterial switch operation, Ross procedure, and coarctation of the aorta. Aortopathy may be an additional risk factor for cardiovascular disease. As ACHD have other abnormalities that may make the heart more vulnerable to both the development of atherosclerosis and adverse cardiovascular sequelae, regular evaluation of their cardiovascular disease risk status is recommended. Metabolic syndrome is more common among ACHD than in the general population, and may therefore increase the future incidence of atherosclerotic coronary artery disease even in ACHD. Thus, ACHD should be screened for metabolic syndrome to eliminate risk factors for atherosclerotic coronary artery disease.

Heart failure in adult congenital heart disease: tetralogy of Fallot

The number of rTOF patients who survive into adulthood is steadily rising, with currently more than 90% reaching the third decade of life. However, rTOF patients are not cured, but rather have a lifelong increased risk for cardiac and non-cardiac complications. Heart failure is recognized as a significant complication. Its occurrence is strongly associated with adverse outcome. Unfortunately, conventional concepts of heart failure may not be directly applicable in this patient group. This article presents a review of the current knowledge on HF in rTOF patients, including incidence and prevalence, the most common mechanisms of heart failure, i.e., valvular pathologies, shunt lesions, left atrial hypertension, primary left heart and right heart failure, arrhythmias, and coronary artery disease. In addition, we will review information regarding extracardiac complications, risk factors for the development of heart failure, clinical impact and prognosis, and assessment possibilities, particularly of the right ventricle, as well as management strategies. We explore potential future concepts that may stimulate further research into this field.

Aortic root replacement in a patient with unoperated tricuspid atresia

A 42-year-old man was referred to our hospital with heart failure and unoperated tricuspid atresia with pulmonary valve stenosis. His condition was initially managed with medical therapy; however, he required repeat hospitalisations for congestive heart failure. We diagnosed the chief cause of his heart failure as aortic valve regurgitation secondary to aortic root dilatation. Aortic root replacement was performed and then his heart failure was controlled.

Impact of Pregnancy on Aortic Root in Women with Repaired Conotruncal Anomalies

The effect of pregnancy on aortic root in women with repaired conotruncal anomalies (CTA) has not been clarified. This study examined aortic diameters during and after pregnancy in women with repaired CTA. A retrospective review of consecutive pregnant women with repaired CTA was performed for results of echocardiography from 1 year before pregnancy to 3 years after delivery and compared with findings from healthy pregnant volunteers. Participants comprised 42 subjects and 49 deliveries with repaired CTA (CTA group), and 47 healthy pregnant women (control group). Although no maternal aortic events were encountered, aortic diameters during pregnancy increased by 1.0 ± 2.2 mm (maximum, 7.0 mm) in the CTA group and 0.6 ± 1.3 mm (maximum, 3.4 mm) in the control group (p = 0.13). The CTA subgroup with increase in aortic diameter ≥ 3.5 mm during pregnancy showed no reversion to baseline diameter at follow-up > 6 months after delivery. Significant risk factors for increased aortic diameter and no reversal included pulmonary atresia, history of aortopulmonary shunt, older age at repair, and smaller left ventricular end-diastolic diameter pre-pregnancy. Women with repaired CTA tolerated pregnancy and delivery well. However, the aortic root progressively dilated during pregnancy and 1/4 of them, especially those with longstanding high aortic blood flow before repair, showed an increase of aortic root size of ≥ 3.5 mm during the peripartum period; this dilatation tended not to revert to the pre-pregnancy diameter. Therefore, serial measurement of the aortic root during pregnancy and after delivery is recommended in these women.

Metabolic Syndrome in Adult Congenital Heart Disease

In adult congenital heart disease (ACHD), residua and sequellae after initial repair develop late complications such as cardiac failure, arrhythmias, thrombosis, aortopathy, pulmonary hypertension and others. Acquired lesions with aging such as hypertension, diabetes mellitus, obesity can be negative influence on original cardiovascular disease (CVD). Also, atherosclerosis may pose an additional health problem to ACHD when they grow older and reach the age at which atherosclerosis becomes clinically relevant. In spite of the theoretical risk of atherosclerosis in ACHD due to above mentioned factors, cyanotic ACHDs even after repair are noted to have minimal incidence of coronary artery disease (CAD). Acyanotic ACHD has similar prevalence of CAD as the general population. However, even in cyanotic ACHD, CAD can develop when they have several risk factors for CAD. The prevalence of risk factor is similar between ACHD and the general population. Risk of premature atherosclerotic CVD in ACHD is based, 3 principal mechanisms: lesions with coronary artery abnormalities, obstructive lesions of left ventricle and aorta such as coarctation of the aorta and aortopathy. Coronary artery abnormalities are directly affected or altered surgically, such as arterial switch in transposition patients, may confer greater risk for premature atherosclerotic CAD. Metabolic syndrome is more common among ACHD than in the general population, and possibly increases the incidence of atherosclerotic CAD even in ACHD in future. Thus, ACHD should be screened for metabolic syndrome and eliminating risk factors for atherosclerotic CAD.

Association of aortic root dilatation with left ventricular function in patients with postoperative ventricular septal defect

Proximal aortic enlargement is associated with an increased risk of heart failure and all-cause mortality. Recently, aortic root dilatation (ARD) was reported in postoperative patients with ventricular septal defects (VSDs). However, the impact of ARD on left ventricular (LV) function in postoperative VSD patients remains unclear. Thus, the aim of this study was to investigate the effect of ARD on LV function in patients with postoperative VSD. One hundred and thirty-five patients (> 15 years of age) with surgically repaired isolated ventricular defects and who underwent transthoracic echocardiography in our institution between 2009 and 2013 were identified. ARD was defined as an observed aortic root diameter/body surface area > 2.1 cm/m². The propensity score estimating the probability of having ARD adjusted for anatomical and clinical characteristics was calculated. Forty-four patients (32.6%) had ARD. In unadjusted analyses, right ventricular systolic pressure, Tei index, and E/e' were significantly (p < 0.05) higher in patients with ARD than in those without ARD (31.3 ± 7.5 vs. 35.4 ± 13.7 mmHg, 0.32 ± 0.10 vs. 0.44 ± 0.15, and 7.1 ± 1.7 vs. 9.5 ± 2.9, respectively). In the propensity score-adjusted analysis, significant differences in the Tei index and E/e' were confirmed between the two groups (Tei index difference: 0.11, 95% confidence interval 0.05-0.17; E/e' difference: 2.4, 95% confidence interval 1.3-3.5). However, there were no differences in the other echocardiographic measurements. The presence of ARD in patients with postoperative VSD was significantly associated with LV diastolic dysfunction. Thus, surgically repaired VSD patients require careful screening for aortic enlargement and LV function.

Aortic dilatation in complex congenital heart disease

A bicuspid aortic valve and/or coarctation of the aorta (COA) are often associated with dilatation of the ascending aorta and para-coarctation. Congenital heart diseases (CHD), such as truncus arteriosus, transposition of the great arteries (TGA), tetralogy of Fallot (TOF), hypoplastic left heart syndrome (HLHS), single ventricle with pulmonary stenosis/atresia and the Fontan procedure, are also associated with aortic root dilatation, aneurysm and rarely, dissection, which can be fatal and require aortic valve and root surgery. A significant subset of adults with complex CHD exhibit progressive dilatation of the aortic root even after repair due to aortic medial degeneration. Medial degeneration in the ascending aorta is prevalent among the above CHD. In Marfan syndrome, bicuspid aortic valve and COA, medial degeneration is more extensive and severe than in another complex CHD. Accordingly, the incidence of ascending aortic dilatation, dissection and rupture is higher in the former. This aortic medial degeneration in CHD may either be intrinsic or secondary to the increased volume overload of the aortic root due to right-to-left shunting, or a combination of both. The association of aortic pathophysiological abnormalities, aortic dilatation and aorto-ventricular interaction is clinically referred to as "aortopathy". The major purpose of medical treatment for aortopathy is to reduce the structural changes within the aortic wall and slow down the progression of aortic dilatation to reduce the risk of cardiovascular events. Several medications have been studied, including β-blockers, angiotensin II type I (AT1) receptor blockers (ARBs) and Ca-antagonists. However, the results, except for Marfan syndrome, are limited. In aortopathy, concomitant aortic valve and aortic root repair/replacement is required. The Bentall operation comprises root replacement with an aortic tube graft and mechanical valve, and has been widely applied. On the other hand, valve-sparing operations have been developed in order to preserve the aortic valve.

Two Cases of Aortic Root Replacement After Fontan Completion

Aortic root dilatation is a well-known complication in patients with congenital aortic valve malformation, tetralogy of Fallot, or a double outlet right ventricle. We report two rare patients who underwent composite graft replacement of the aortic root with a mechanical valve, the so-called Bentall-type operation, after Fontan completion. The pathological examination on the resected aortic wall revealed mucoid degeneration in tunica media and elastic fiber fragmentation. Our report emphasizes the need for close observation of these patients over a long-term period.

Multiple saccular aortic aneurysms following the arterial switch operation

We report a 3-month-old male presenting with multiple aortic aneurysms arising de novo 2 months following the arterial switch operation. Successful repair of the aneurysms was performed under total circulatory arrest and at seven years follow-up, the patient has no recurrence.

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".

Factors associated with aortic root dilatation after surgically repaired ventricular septal defect

BACKGROUND

Aortic root dilatation (ARD) in congenital heart disease is related to aortic aneurysm, rupture, and dissection. This study aimed to investigate the factors associated with ARD in patients with surgically repaired ventricular septal defect (VSD).

METHODS

This cross-sectional study included 152 patients with surgically repaired VSD. Two definitions of ARD were used: (1) observed Valsalva diameter to body surface area (BSA) ratio >2.1 cm/m² and (2) absolute value of Valsalva diameter ≥4.0 cm. Odds ratios (ORs) and 95% confidence intervals (CIs) of ARD presence were calculated using multivariate logistic regressions.

RESULTS

The prevalence of ARD ranged between 8.6% and 32.9%. Using the definition of observed aortic root diameter/BSA >2.1 cm/m² , patients with nonsubarterial VSD type were more likely to have ARD (OR 5.65, 95% CI; 1.83-17.44, P=.003) than those with subarterial type, and patients with preoperative right- or noncoronary cusp prolapse (R/NCCP) were more likely to have ARD (OR 3.68, 95% CI; 1.20-11.23, P=.022) than patients without preoperative R/NCCP after adjustment for sex, age at repair (ie, shunt duration), VSD size, and postoperative follow-up period. Using the definition of absolute Valsalva diameter ≥4 cm, nonsubarterial VSD type and presence of R/NCCP were also significantly associated with ARD after adjustment for the same covariates.

CONCLUSIONS

Anatomical and morphological features (nonsubarterial type and presence of preoperative R/NCCP) are independently correlated with ARD in patients with VSD regardless of the different definitions of ARD. Patients with surgically repaired VSD may need careful monitoring for potential ARD development.

Holodiastolic Flow Reversal at the Descending Aorta on Cardiac Magnetic Resonance is Neither Sensitive Nor Specific for Significant Aortic Regurgitation in Patients with Congenital Heart Disease

Holodiastolic flow reversal in the descending aorta on echocardiogram suggests significant aortic regurgitation. The study aim was to determine whether the presence of holodiastolic flow reversal on cardiac magnetic resonance imaging (MRI) correlates with aortic valve regurgitant fraction. We retrospectively reviewed 166 cardiac MRIs (64 % male, age 14.1 ± 9.5 years) from January 2011 to May 2012 where velocity mapping was acquired at both the aortic valve and the descending aorta at the level of the diaphragm. Descending aorta velocity maps were checked for baseline offset using a static reference region. Holodiastolic flow reversal was defined as flow reversal throughout diastole both before and after baseline correction. Significant aortic regurgitation was defined as regurgitant fraction >10 %. Aortic valve regurgitant fraction was <10 % in 144 patients (Group A), 10-20 % inclusive in 7 patients (Group B), and >20 % in 15 patients (Group C). Though the aortic valve regurgitant fraction was significantly higher for patients with holodiastolic flow reversal versus those without (8.5 ± 14.2 vs. 3.8 ± 6.6 %, p = 0.02), holodiastolic flow reversal was present in 32 Group A patients (22 %). In comparison, 4 Group B patients (57 %) and 7 Group C patients (47 %) had holodiastolic flow reversal. The sensitivity (Groups B and C) was 0.5, and the specificity (Group A) was 0.78. Holodiastolic flow reversal in the descending aorta on cardiac MRI was neither sensitive nor specific for predicting significant aortic regurgitation in this study population. Holodiastolic flow reversal in the absence of significant aortic regurgitation may be a relatively common finding in patients with congenital heart disease.

Aortic stenting in the growing sheep causes aortic endothelial dysfunction but not hypertension: Clinical implications for coarctation repair

BACKGROUND

Stent implantation is the treatment of choice for adolescents and adults with aortic coarctation (CoAo). Despite excellent short-term results, 20%-40% of the patients develop arterial hypertension later in life, which was attributed to inappropriate response of the aortic baroreceptors to increased stiffness of the ascending aorta (ASAO), either congenital or induced by CoAo repair. In particular, it has been hypothesized that stent itself may cause or sustain hypertension. Therefore, we aimed to study the hemodynamic and structural impact following stent implantation in the normal aorta of a growing animal.

METHODS

Eight female sheep completed the study and a stent was implanted in four. Every 3 mo we measured blood pressure of the anterior and posterior limbs and left ventricular function by echocardiography. Twelve months later invasive pressure was measured under baseline and simulated stress conditions. Expression of genes indicating oxidative stress (OS), endothelial dysfunction (ED) and stiffness, as well as pathological examination were performed in ascending (ASAO) and descending aorta (DSAO).

RESULTS

SOD1 and MMP9 gene expression were higher in ASAO of the stented animals, compared to DSAO and controls, while NOS3 was decreased. No differences were found in blood pressure and echocardiographic parameters. No histological differences were found in the aorta of the two groups of animals.

CONCLUSIONS

Stent does not affect central and peripheral hemodynamics, cardiac structure and function even in the long term. However, the finding of markers of OS and increased stiffness of ASAO, proximal to the stent, points to molecular mechanisms for increased cardiovascular risk of patients with stented CoAo.

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.

Successful Bentall procedure in a patient with a Fontan circulation

A 33-year old male patient with absent left atrioventricular connection and double outlet left ventricle developed severe aortic root dilatation and aortic regurgitation. He had undergone initial banding of the pulmonary trunk and atrial septectomy, eventually followed by the bidirectional Glenn procedure. At the time of the total cavopulmonary connection (at 27 years of age), his ascending aorta was plicated and wrapped. Subsequently, the aortic root below the wrapped ascending aorta showed further dilatation. The Bentall procedure was successfully carried out.

Clinical outcome, valve dysfunction, and progressive aortic dilation in a pediatric population with isolated bicuspid aortic valve

The aim of this study was to explore the medium-term clinical outcome and the risk of progression of aortic valve disease and aortic dilation in pediatric patients with isolated bicuspid aortic valve (BAV). 179 pediatric patients with isolated BAV were prospectively followed from January 1995 to December 2010. Patients with severe valve dysfunction at baseline were excluded. Clinical outcome included cardiac death, infective endocarditis, aortic complications, cardiac surgery and percutaneous valvuloplasty. Echocardiographic endpoints were: progression of aortic stenosis (AS) or regurgitation (AR) and progressive aortic enlargement at different levels of the aortic root, evaluated as z-score. The median age at diagnosis was 7.8 [2.7-12.0] years. After a median followup of 5.4 [2.3-9.2] years, all patients were alive. The clinical endpoint occurred in 4 (2.2 %) patients (0.41 events per 100 patient-years). A progression of AS and AR was observed in 9 (5.0 %) and 29 (16.2 %) patients, respectively. The z-scores at the end of follow-up were not significantly different from baseline at the annulus, Valsalva sinuses and sinotubular junction, whereas a slight increase was observed at the level of the ascending aorta (1.9 vs 1.5, p = 0.046). Significant progressive aortic dilation occurred in a minority of patients (10.6, 5.6, 9.5, and 19.0 % respectively). The clinical outcome in pediatric patients with isolated BAV is favourable and the progression of aortic valve dysfunction and aortic dilation is relatively slow. These findings may be taken into account to better guide risk assessment and clinical follow-up in these patients.