Morphology and function of the bicuspid aortic valve with and without coarctation of the aorta in the young

miR-130a expression is related to aortic dilation in bicuspid aortic valve children

BACKGROUND

Bicuspid aortic valve disease (BAV) is present in 0.5-2% of the population and can promote aortic dilation, eventually leading to fatal consequences. Although some biomarkers have been proposed in adults, no studies have tested these candidates in children. We aimed to evaluate four miRNAs previously described to be related to BAV disease and aortic dilation in adults in a paediatric cohort.

METHODS

Eighty participants ≤17 years old (4-17; mean 12) were included. From the BAV group, 40% had a dilated aorta (z score >2). RT‒qPCR were performed in plasma samples to quantify miR-122, miR-130a, miR-486, and miR-718 using the delta-delta Ct method. Functional and enrichment analyses of miR-130a were also performed.

RESULTS

miR-130a expression in plasma was found to be significantly lower in BAV patients with a dilated aorta versus nondilated patients (p = 0.008) and healthy TAV controls (p = 0.004). Furthermore, miR-130a expression in plasma was inversely correlated with ascending aorta (r = 0.318, p = 0.004) and aortic root z scores (r = 0.322; p = 0.004). Enrichment analysis showed that miR-130a target genes are related to the TGFβ signalling pathway.

CONCLUSIONS

miR-130a expression in plasma is decreased in aortic-dilated BAV children compared to nondilated BAV children, helping differentiate low- to high-risk patients.

IMPACT

miR-130a expression in plasma is related to aortic dilation in bicuspid aortic valve (BAV) children. To our knowledge, this is the first study that analyses miRNA patterns in bicuspid aortic valve children with aortic dilation. miR-130a expression in plasma could be a biomarker in order to help differentiate low-to high-risk BAV children, which is vitally important for advanced care planning.

Pitfalls and Tips in the Assessment of Aortic Stenosis by Transthoracic Echocardiography

Aortic stenosis (AS) is a valvular heart disease that significantly contributes to cardiovascular morbidity and mortality worldwide. The condition is characterized by calcification and thickening of the aortic valve leaflets, resulting in a narrowed orifice and increased pressure gradient across the valve. AS typically progresses from a subclinical phase known as aortic sclerosis, where valve calcification occurs without a transvalvular gradient, to a more advanced stage marked by a triad of symptoms: heart failure, syncope, and angina. Echocardiography plays a crucial role in the diagnosis and evaluation of AS, serving as the primary non-invasive imaging modality. However, to minimize misdiagnoses, it is crucial to adhere to a standardized protocol for acquiring echocardiographic images. This is because, despite continuous advances in echocardiographic technology, diagnostic errors still occur during the evaluation of AS, particularly in classifying its severity and hemodynamic characteristics. This review focuses on providing guidance for the imager during the echocardiographic assessment of AS. Firstly, the review will report on how the echo machine should be set to improve image quality and reduce noise and artifacts. Thereafter, the review will report specific emphasis on accurate measurements of left ventricular outflow tract diameter, aortic valve morphology and movement, as well as aortic and left ventricular outflow tract velocities. By considering these key factors, clinicians can ensure consistency and accuracy in the evaluation of AS using echocardiography.

Beyond Aortic Stenosis: Addressing the Challenges of Multivalvular Disease Assessment

Aortic stenosis (AS) can often coexist with other valvular diseases or be combined with aortic regurgitation (AR), leading to unique pathophysiological conditions. The combination of affected valves can vary widely, resulting in a lack of standardized diagnostic or therapeutic approaches. Echocardiography is crucial in assessing patients with valvular heart disease (VHD), but careful consideration of the hemodynamic interactions between combined valvular defects is necessary. This is important as it may affect the reliability of commonly used echocardiographic parameters, making the diagnosis challenging. Therefore, a multimodality imaging approach, including computed tomography or cardiac magnetic resonance, is often not just beneficial but crucial. It represents the future of diagnostics in this intricate field due to its unprecedented capacity to quantify and comprehend valvular pathology. The absence of definitive data and guidelines for the therapeutic management of AS in the context of multiple valve lesions makes this condition particularly challenging. As a result, an individualized, case-by-case approach is necessary, guided primarily by the recommendations for the predominant valve lesion. This review aims to summarize the pathophysiology of AS in the context of multiple and mixed valve disease, with a focus on the hemodynamic implications, diagnostic challenges, and therapeutic options.

Concomitant cardiovascular malformations in isolated bicuspid aortic valve disease: a retrospective cross-sectional study and meta-analysis

Background

Congenital bicuspid aortic valve affects up to 2% of the general population. It occurs in complex congenital heart defects or in syndromes such as Turner, Marfan, or Loeys-Dietz. However, the majority of bicuspid aortic valves are considered to manifest as isolated malformations.

Methods

We aimed to assess retrospectively associated cardiovascular malformations in 200 individuals with bicuspid aortic valve considered to occur as an isolated manifestation. All individuals underwent transthoracic echocardiography, 164 thoracoabdominal tomographic imaging, and 84 coronary artery imaging. In addition, we also performed a meta-analysis of data from the literature to assess the occurrence of associate malformations.

Results

In our retrospective cross-sectional study collective, the mean age was 45±15 years, 154 (77%) individuals were male. Anatomy of bicuspid aortic valve according to Schaefer was type 1 in 142 (71%), type 2 in 35 (18%), type 3 in 2 (1%), unicuspid in 6 (3%), and unclassified in 15 (8%) individuals. Coarctation of the aorta had 4.2% of individuals, 3.6% had coronary anomalies. No individual had a patent ductus arteriosus, 0.5% had atrial and ventricular septal defect each, 1.5% mitral valve prolapse. No individual had a tricuspid valve prolapse. Our meta-analysis identified in cohorts with isolated bicuspid aortic valve 11.8% (95% CI: 7.7–16.0%) individuals with aortic coarctation, 3.7% (95% CI: 1.2–6.1%) with coronary anomalies, 3.3% (95% CI: 0.0–6.7%) with patent ductus arteriosus, 5.9% (95% CI: 1.3–10.5%) with ventricular septal defect and 1.6% (95% CI: 1.1–2.1%) with mitral valve prolapse.

Conclusions

Individuals with isolated bicuspid aortic valve may exhibit a variety of associated cardiovascular malformations and therefore screening for associated malformations may be warranted.

The association between cardiac magnetic resonance-derived aortic stiffness parameters and aortic dilation in young adults with bicuspid aortic valve: With and without coarctation of aorta

Background

Bicuspid aortic valve (BAV) is associated with progressive aortic dilation. Studies in aortopathies have shown a correlation between increased aortic stiffness and aortic dilation. We aimed to evaluate aortic stiffness measures as predictors of progressive aortic dilation by cardiac magnetic resonance (CMR) in BAV patients.

Methods

This is a retrospective study of 49 patients with BAV (median age 21.1 years at first CMR visit) with ≥2 CMR at the Wisconsin Adult Congenital Heart Disease Program (WAtCH). Circumferential aortic strain, distensibility, and β-stiffness index were obtained from CMR-derived aortic root cine imaging, and aortic dimensions were measured at aortic root and ascending aorta. A linear mixed-model and logistic regression were used to identify important predictors of progressive aortic dilation.

Results

Over a median of 3.8 years follow-up, the annual growth rates of aortic root and ascending aorta dimensions were 0.25 and 0.16 mm/year, respectively. Aortic strain and distensibility decreased while β-stiffness index increased with age. Aortic root strain and distensibility were associated with progressive dilation of the ascending aorta. Baseline aortic root diameter was an independent predictor of >1 mm/year growth rate of the aortic root (adjusted OR 1.34, 95 % CI 1.03-1.74, p = 0.028). Most patients (61 %) had coexisting coarctation of aorta. Despite the higher prevalence of hypertension in patients with aortic coarctation, hypertension or coarctation had no effect on baseline aorta dimensions, stiffness, or progressive aortic dilation.

Conclusion

Some CMR-derived aortic stiffness parameters correlated with progressive aortic dilation in BAV and should be further investigated in larger and older BAV cohorts.

Bicuspid Aortic Valve Disease from Infancy to Older Age: A 25-Year Experience from an Italian Referral Center

Aim:

Bicuspid aortic valve (BAV) is the most common congenital heart defect, with considerable risk of morbidity and mortality. The purpose of the study was to analyze clinical and echocardiographic presentation of BAV in a large-volume tertiary Italian center and to test their interaction with full age span, sex, and first diagnosis versus second referral.

Methods:

Consecutive patients of all ages diagnosed with BAV at our center from January 1988 to December 2012 were retrospectively included. Exclusion criteria were as follows: associated complex congenital cardiac disease, systemic syndrome, and previous cardiac surgery.

Results:

Eligible patients were 790, divided by age quartiles. Seventy-two percent of patients had any grade BAV dysfunction. Aortic valve stenosis was more frequent in the first (24%) and fourth (24%) quartiles. This corresponds to a double-peak stenosis severity curve, being more severe at a very young age and in the elderly. Aortic valve regurgitation was more prevalent in each quartile than stenosis, with a prevalence of 72% in the second quartile and 77% in the third quartile. This corresponds to a single-peak regurgitation severity curve, being more severe in the fourth and fifth decades of life. Patients with previously diagnosed BAV had more significant valve dysfunction in comparison to patients with first diagnosis of BAV, either stenosis (15% vs. 21%, P = 0.024) or regurgitation (58% vs. 68%, P = 0.006).

Conclusion:

The dominant BAV dysfunction in this large Northern Italian community is regurgitation, with higher severity of disease in the fourth and fifth decades of life.

Genetics in bicuspid aortic valve disease: Where are we?

Bicuspid aortic valve (BAV) is the most common congenital heart defect, found in up to 2% of the population and associated with a 30% lifetime risk of complications. BAV is inherited as an autosomal dominant trait with incomplete penetrance and variable expressivity due to a complex genetic architecture that involves many interacting genes. In this review, we highlight the current state of knowledge about BAV genetics, principles and methods for BAV gene discovery, clinical applications of BAV genetics, and important future directions.

An incidental finding of a bicuspid aortic valve and pseudocoarctation of the descending aorta in a patient presenting with an acute coronary syndrome: a case report

Background

Aortic pseudocoarctation (PsCoA) is an elongation of the supra-isthmic aorta with kinking and low-grade narrowing. Consequently, no collateral circulation is found. It is frequently associated with other congenital heart anomalies, such as bicuspid aortic valve (BAV).

Case summary

We report the case of 60-year-old patient who presented to the ED with acute chest pain. Physical examination was remarkable for an elevated blood pressure (BP) and the presence of a systolic murmur on the left lower sternal border. An acute coronary syndrome was suspected and the patient underwent urgent coronary angiogram which showed an occluded obtuse marginal artery. Additionally, the presence of an aortic anomaly was noted during the aortography, and additional work-up, including a thoracic computed tomography angiography and transoesophageal echocardiography, revealed a BAV and a PsCoA of the descending aorta. The patient was discharged after optimizing BP control with oral medication and periodical follow-up was arranged.

Discussion

Aortic PsCoA may mimic true coarctation (CoA), but the absence of a haemodynamically significant descending aortic narrowing and of the typical clinical findings associated with aortic CoA, distinguishes both entities. Treatment is therefore conservative and based on the control of cardiovascular risk factors and in particular of arterial hypertension. Work-up should include imaging of the entire aorta and the search for associated congenital cardiac anomalies, which, if present, should be managed in consequence.

Differences in Aortopathy in Patients with a Bicuspid Aortic Valve with or without Aortic Coarctation

Objective: The combination of aortic coarctation (CoA) and bicuspid aortic valve (BAV) is assumed to be associated with a higher risk of ascending aortic dilatation and type A dissection, and current European Society of Cardiology (ESC) guidelines advise therefore to operate at a lower threshold in the presence of CoA. The aim of our study is to evaluate whether the coexistence of CoA in BAV patients is indeed associated with a higher risk of ascending aortic events (AAE). Methods: In a retrospective study, all adult BAV patients visiting the outpatient clinic of our tertiary care center between February 2003 and February 2019 were included. The primary end point was an ascending aortic event (AAE) defined as ascending aortic dissection/rupture or preventive surgery. The secondary end points were aortic dilatation and aortic growth. Results: In total, 499 BAV patients (43.7% female, age 40.3 ± 15.7 years) were included, of which 121 (24%) had a history of CoA (cBAV). An aortic event occurred in 38 (7.6%) patients at a mean age of 49.0 ± 13.6 years. In the isolated BAV group (iBAV), significantly more AAE occurred, but this was mainly driven by aortic valve dysfunction as indication for aortic surgery. There was no significant difference in the occurrence of dissection or severely dilated ascending aorta (>50 mm) between the iBAV and cBAV patients (p = 0.56). The aortic diameter was significantly smaller in the cBAV group (30.3 ± 6.9 mm versus 35.7 ± 7.6 mm; p < 0.001). The median aortic diameter increase was 0.23 (interquartile range (IQR): 0.0–0.67) mm/year and was not significantly different between both groups (p = 0.74). Conclusion: Coexistence of CoA in BAV patients was not associated with a higher risk of aortic dissection, preventive aortic surgery, aortic dilatation, or more rapid aorta growth. This study suggests that CoA is not a risk factor in BAV patients, and the advice to operate at lower diameter should be reevaluated.

Bicuspid aortic valve and aortic coarctation in congenital heart disease-important aspects for treatment with focus on aortic vasculopathy

Prevalence of congenital heart disease (CHD) is constantly increasing during the last decades in line with the treatment options for patients ranging from the surgical as well to the interventional spectrum. This mini-review addresses two of the most common defects with bicuspid aortic valve (BAV) and coarctation of the aorta (CoA). Both diseases are connected to aortic vasculopathy which is one of the most common reasons for morbidity and mortality in young patients with CHD. The review will focus as well on other aspects like medication and treatment of pregnant patients with BAV and CoA. New treatment aspects will be as well reviewed as currently there are additional treatment options to treat aortic regurgitation or aortic aneurysm especially in patients with valvular involvement and a congenital BAV thus avoiding replacement of the aortic valve and potentially improving the future therapy course of the patients.

Abnormal aortic stiffness in patients with bicuspid aortic valve: phenotypic variation determined by magnetic resonance imaging

The aim of this study was to assess aortic stiffness in patients with bicuspid aortic valve (BAV), and to determine if differences exist among the BAV phenotypes. Stiffness was measured by pulse wave velocity (PWV) determined using velocity-encoded magnetic resonance imaging (VENC-MRI). VENC-MRI was performed in 100 BAV patients and 45 normal controls. PWV was determined between the mid ascending and mid descending aorta. The BAV phenotypes were characterized using steady-state free precession (SSFP) images acquired across the face of the aortic valve, and classified as follows: right-left cusp (R-L) fusion, right and non-coronary cusp (R-NC) fusion, and left and non-coronary cusp (L-NC) fusion. The following BAV phenotypes were identified: 76 R-L, 23 R-NC, and 1 L-NC fusion. BAV patients demonstrated significantly greater PWV compared to normal controls, after adjusting for age (9.16 vs. 3.83 m/s; p < 0.0001). Furthermore, PWV was significantly greater in patients with R-NC fusion than those with R-L fusion phenotype (12.27 vs. 7.97 m/s; p < 0.001). There was significantly increased PWV from VENC-MRI in BAV patients compared to normal controls. Thisis the first to demonstrate the association of different BAV phenotypes and aortic stiffness. VENC-MRI PWV assessment potentially represents a novel parameter for enhanced surveillance and may alter surgical triage of aorta in this high risk group.

Echocardiographic manifestations and chemical composition of stenotic bicuspid aortic valves

Bicuspid aortic valve (BAV) is an inherited form of heart disease with only two aortic valve leaflets via a disorder of cardiac valvulogenesis. We investigated the in vivo echocardiographic features of cardiac morphology in patients with BAV and the ex vivo compositional components of all the excised BAV leaflets isolated from BAV patients. Three BAV patients were randomly selected. All patients underwent 2D transthoracic echocardiography (TTE) with a Doppler ultrasound tool. The compositional components of each respective BAV leaflet for all the excised BAVs were determined by a portable fiber-optic Raman spectroscopy. Preoperative TTE revealed the thickened and calcified BAV leaflets, and stenotic aortic flow for all BAV patients. These BAV patients exhibited severe aortic stenosis (AS) by the lower values of aortic valve area (AVA) index. One patient showed a more significant left ventricle hypertrophy, whereas two patients exhibited a significant aortic regurgitation (AR). In addition, three different Raman spectral patterns were summed up from 121 randomized Raman determinations for all the excised BAV leaflets. The main calcified deposition in each BAV leaflet was formed by large amounts of calcium hydroxyapatite and type-B carbonate apatite (Raman bands at 960 and 1070 cm^-1). The calcified BAV leaflets were composed of different compositional components such as calcium hydroxyapatite, type-B carbonate apatite, lipids, proteins, cholesterol and β-carotene. The rare NL subtype of type 1 BAV morphotype was found in one patient, but two patients had the purely BAV morphotype with two equal-sized leaflets.

Impact of Bicuspid Aortic Valve Morphology on Aortic Valve Disease and Aortic Dilation in Pediatric Patients

Bicuspid aortic valve (BAV) is the most common congenital heart defect. BAV is associated with aortic stenosis and insufficiency, and aortic dilation in adult groups, but data in pediatric groups are limited. We sought to assess the impact of BAV morphology on aortic valve disease and aortic dilation in pediatric patients. We performed a retrospective review of all echocardiograms in patients with isolated BAV who were followed at our institution from July 2002 to July 2012. BAV morphology, aortic valve stenosis and/or insufficiency, and aortic dimensions were measured manually. Comparisons were made between right-left cusp fusion (RL) and right-noncoronary cusp fusion (RN) BAV morphologies. Generalized least square models were fit to analyze the impact of specific variables on aortic dilation. There were 1075 echocardiograms in 366 patients (72% male) with isolated BAV. Aortic valve insufficiency and stenosis were more common in RN (p < 0.001 for both). The median aortic sinus Z score was higher in the RL (0.47; IQR - 0.31 to 1.44) than in the RN group (0.02; - 0.83 to 0.82) (p < 0.001). There was no difference in median ascending aorta Z score between groups. Patients with the highest weights had larger aortas (p < 0.001), but the absolute difference between the highest and lowest weight groups was small (1.5 mm). The impact of BAV morphology on aortic valve disease and aortic dilation in pediatric patients presages that seen in adults. Patient body weight does not make significant clinical impacts on aortic diameters, suggesting that Z scores for aortic diameters should be based on ideal body weights.

Population-based treated prevalence, risk factors, and outcomes of bicuspid aortic valve in a pediatric Medicaid cohort

Background:

We investigated the treated prevalence of bicuspid aortic valve in a pediatric population with congenital heart disease and its incident complications.

Materials and Methods:

A 15-year retrospective data set was analyzed. Selection criteria included age ≤17 years, enrollees in the South Carolina State Medicaid program and diagnosed as having bicuspid aortic valve on one or more service visits.

Results:

The 15-year-treated prevalence of predominantly isolated bicuspid aortic valve was 2% (20/1000) of pediatric congenital heart disease cases, with a non-African American: African-American ratio of 3.5:1, and a male:female ratio of 1.6:1. Aortic stenosis (28.0%), ventricular septal defect (20.6%), and coarctation of the aorta (20.6%) were the most prevalent coexisting congenital heart lesions. Of the 378 bicuspid aortic valve cases examined, 10.3% received aortic valve repair/replacement, which was significantly more likely to be performed in children with diagnosed aortic stenosis (adjusted odds ratio = 12.90; 95% confidence interval = 5.66–29.44). Cohort outcomes over the study period indicated that 9.5% had diagnosed heart failure, but <1% had diagnosed supraventricular tachycardia, infective endocarditis, aneurysm, dissection, or death.

Conclusions:

The majority of isolated bicuspid aortic valve cases without aortic stenosis did not require surgical intervention. Outcomes for cases requiring repair/replacement were relatively benign.

Ascending aortic size in aortic coarctation depends on aortic valve morphology: Understanding the bicuspid valve phenotype

BACKGROUND

In roughly half of patients with coarctation of the aorta (CoA), the aorta may be enlarged. It is uncertain whether enlargement is independent of aortic valve morphology. We sought to compare aortic size in CoA with a tricuspid valve (TAV) to those with bicuspid aortic valve (BAV).

METHODS

Sixty-eight CoA patients and 20 healthy controls with prior cardiac magnetic resonance (CMR) imaging were included. CMR was retrospectively reanalyzed to measure aortic root and mid-ascending aorta. The maximum aortic diameter was compared between CoA with TAV, CoA with BAV, and control groups.

RESULTS

CoA with TAV patients (n=27) had smaller aortic root diameters than CoA with BAV (n=41) (32±4.9 vs. 37±5.8mm, p=0.001), despite being older (40 vs. 32years, p=0.01). Similarly, TAV CoA patients had a smaller mid-ascending aortic diameter (28±4.5 vs. 33±6.9mm, p=0.019) than BAV patients. TAV CoA was similar to controls in all metrics. Twenty-four patients (35%) with CoA had dilated aortas (>37mm), of which 79% had BAV. A history of hypertension did not predict larger aortic root or mid-ascending aortic dimensions.

CONCLUSIONS

In patients with CoA, TAV is associated with smaller aortic size compared to those with BAV, and similar to healthy controls. Aortic size in CoA is independent of hypertension. Therefore, aortopathy associated with BAV is likely a reflection of the BAV phenotype rather than CoA or its physiologic effects. This distinction may have implications for the frequency and types of monitoring and treatment of CoA patients.

Aortic Diameter Growth in Children With a Bicuspid Aortic Valve

Knowledge of aortic growth in patients with bicuspid aortic valve (BAV) is essential to identify patients at risk for dissection, but data on children remain unclear. We retrospectively evaluated the aortic diameters of all pediatric BAV patients, identified through an echocardiographic database (2005 to 2013). Medical records were reviewed and aortic diameters re-measured on echocardiographic images at diagnosis and if available on variable mid- and endpoints follow-up. Dilatation (z-score >2) was based on 2 different z-score equation methods (Gautier/Campens). In 234 of the total 250 BAV patients, aortic diameters were analyzed; median age was 6.1 years (interquartile range 1.7 to 10), of which 63% were male. Aortic coarctation was present in 81 (36%) patients, 23% had a ventricular septal defect. BAV morphology according to Sievers was as follows: type 0 in 128 patients (55%), type 1 in 96 (41%), and type 2 in 10 (4%). Ascending aortic (AA) dilatation was present in 24% (Gautier) and 36% (Campens) at inclusion. Median follow-up was 4.7 years. The AA was the only location where mean z-scores progressed significantly with age: 0.06 (Gautier) and 0.09 (Campens) units per year between ages 5 and 15 years. Associations for higher AA z-scores at older age were an initial z-score >2 (p <0.001) and aortic valve stenosis (p <0.05). Neither dissection nor preventive aortic surgery occurred. In conclusion, only the AA seems at risk for complication, although no aortic complications occurred in this pediatric BAV cohort. BAV morphology seems associated with larger AA z-scores and valvular dysfunction.

Clinical and echocardiographic predictors of long-term outcome of a large cohort of patients with bicuspid aortic valve

BACKGROUND AND OBJECTIVES

Bicuspid aortic valve (BAV) disease is the most common congenital cardiac malformation. The aim of the present article is to determine clinical and echocardiographic prognostic factors and provide a predictive model of outcome of a large cohort of patients with BAV.

METHODS

We retrospectively enrolled 337 patients consecutively assessed for echocardiography at our Cardiology Department from 1993 to 2014. We considered aortic valve replacement, aortic surgery and cardiovascular death as a clinical combined end-point. Predictors of outcome were determined by Cox regression.

RESULTS

Mean age was 29.2 ± 19.8 years, median 27.1 years. A total of 38.4% patients presented a history of hypertension. Mean duration of follow-up was 8.4 ± 6.1 years, range 0-21 years. A total of 73 patients underwent aortic valve replacement and/or aortic surgery during follow-up. Age at surgery was 45.2 ± 15.6 years. Seven patients died because of cardiovascular causes. At multivariate analysis, baseline clinical predictors were history of hypertension [hazard ratio (HR) 2.289, 95% confidence interval (CI) 1.350-3.881, P = 0.002], larger ascending aortic diameter (HR 2.537, 95% CI 1.888-3.410, P < 0.001), moderate-to-severe aortic regurgitation (HR 2.266, 95% CI 1.402-3.661, P = 0.001) and moderate-to-severe aortic stenosis (HR 2.807, 95% CI 1.476-5.338, P = 0.002). A predictive model was created by integrating these four independent covariates. It allows the calculation of calculate a risk score for each patient, which helps better tailor appropriate treatment in BAV patients.

CONCLUSION

At enrolment, history of hypertension, a wider aortic diameter, moderate-to-severe aortic regurgitation and aortic stenosis were independently correlated to combined end-point. Long-term follow-up showed low cardiovascular mortality (2.1%) and a high prevalence of cardiac surgery (21.6%).

Bicuspid Aortic Valve: Unlocking the Morphogenetic Puzzle

Although bicuspid aortic valve is the most common congenital abnormality, it is perhaps erroneous to consider this disease one clinical entity. Rather, it may be useful to consider it a cluster of diseases incorporating different phenotypes, etiologies, and pathogenesis. Discussion of bicuspid aortic valve can be difficult because there is no clear consensus on a phenotypic description among authors, and many classification schemes have been proposed. The literature suggests that different phenotypes have different associations and clinical manifestations. In addition, recent studies suggest a genetic basis for the disease, yet few genes have so far been described. Furthermore, recent scientific literature has been focusing on the increased risk of aortic aneurysms, but the pathogenesis of bicuspid aortic valve aortopathy is still unclear. The aim of this paper is to review the current evidence about the unsolved issues around bicuspid aortic valve.

The extent of the raphe in bicuspid aortic valves is associated with aortic regurgitation and aortic root dilatation

Background

The clinical course of bicuspid aortic valves (BAVs) is variable. Data on predictors of aortopathy and valvular dysfunction mainly focus on valve morphology.

Aim

To determine whether the presence and extent of the raphe (fusion site of valve leaflets) is associated with the degree of aortopathy and valvular dysfunction in patients with isolated BAV and associated aortic coarctation (CoA).

Methods

Valve morphology and aortic dimensions of 255 BAV patients were evaluated retrospectively by echocardiography.

Results

BAVs with a complete raphe had a significantly higher prevalence of valve dysfunction (especially aortic regurgitation) than BAVs with incomplete raphes (82.9 vs. 66.7 %, p = 0.01). Type 1A BAVs (fusion of right and left coronary leaflets) and complete raphe had larger aortic sinus diameters compared with the rest of the population (37.74 vs. 36.01, p = 0.031). Patients with CoA and type 1A BAV had significantly less valve regurgitation (13.6 vs. 55.8 %, p < 0.001) and smaller diameters of the ascending aorta (33.7 vs. 37.8 mm, p < 0.001) and aortic arch (25.8 vs. 30.2 mm, p < 0.001) than patients with isolated BAV.

Conclusions

Type 1A BAV with complete raphe is associated with more aortic regurgitation and root dilatation. The majority of CoA patients have incomplete raphes, associated with smaller aortic root diameters and less valve regurgitation.

Near-fatal neonatal coronary ischaemia associated with intermittent aortic regurgitation: successful surgical treatment

An infant presented with features suggestive of an anomalous left coronary artery was found to have normal origins of both coronary arteries. Echocardiography during episodes of ischaemia showed marked aortic regurgitation with retrograde coronary flow. The left coronary leaflet was mildly hypoplastic. Surgical re-suspension of this leaflet prevented aortic regurgitation and the patient had no further symptoms and recovered cardiac function.

Imaging of cardiovascular risk in patients with Turner's syndrome

Turner's syndrome is a disorder defined by an absent or structurally abnormal second X chromosome and affects around 1 in 2000 newborn females. The standardised mortality ratio in Turner's syndrome is around three-times higher than in the general female population, mainly as a result of cardiovascular disorders. Most striking is the early age at which Turner's syndrome patients develop the life-threatening complications of cardiovascular disorders compared to the general population. The cardiovascular risk stratification in Turner's syndrome is challenging and imaging is not systematically used. The aim of this article is to review cardiovascular risks in this group of patients and discuss a systematic imaging approach for early identification of cardiovascular disorders in these patients.

Thoracic aorta 3D hemodynamics in pediatric and young adult patients with bicuspid aortic valve

BACKGROUND

To evaluate the 3D hemodynamics in the thoracic aorta of pediatric and young adult bicuspid aortic valve (BAV) patients.

METHODS

4D flow MRI was performed in 30 pediatric and young adult BAV patients (age: 13.9 ± 4.4 (range: [3.4, 20.7]) years old, M:F = 17:13) as part of this Institutional Review Board-approved study. Nomogram-based aortic root Z-scores were calculated to assess aortic dilatation and degree of aortic stenosis (AS) severity was assessed on MRI. Data analysis included calculation of time-averaged systolic 3D wall shear stress (WSSsys ) along the entire aorta wall, and regional quantification of maximum and mean WSSsys and peak systolic velocity (velsys ) in the ascending aorta (AAo), arch, and descending aorta (DAo). The 4D flow MRI AAo velsys was also compared with echocardiography peak velocity measurements.

RESULTS

There was a positive correlation with both mean and max AAo WSSsys and peak AAo velsys (mean: r = 0.84, P < 0.001, max: r = 0.94, P < 0.001) and AS (mean: rS  = 0.43, P = 0.02, max: rS  = 0.70, P < 0.001). AAo peak velocity was significantly higher when measured with echo compared with 4D flow MRI (2.1 ± 0.98 m/s versus 1.27 ± 0.49 m/s, P < 0.001).

CONCLUSION

In pediatric and young adult patients with BAV, AS and peak ascending aorta velocity are associated with increased AAo WSS, while aortic dilation, age, and body surface area do not significantly impact AAo hemodynamics. Prospective studies are required to establish the role of WSS as a risk-stratification tool in these patients.

Bicuspid aortic valve: phosphorylation of c-Kit and downstream targets are prognostic for future aortopathy

OBJECTIVES

The clinical course of many patients with a bicuspid aortic valve (BAV) is complicated by ascending aortic dilatation. Currently, the indication for aortic surgery is solely based on the aortic diameter and subsequently only a small proportion of BAV patients undergoing valve surgery require concomitant ascending aortic replacement based on these recommendations. Unfortunately, a substantial number of BAV patients still develop aortic dilatation in the future and would potentially benefit from a more aggressive approach towards ascending aortic replacement. We, therefore, designed this study to identify molecular biological markers in the aortic wall predictive of aortopathy in BAV.

METHODS

Ascending aortic wall specimen of BAV (n = 36) and tricuspid aortic valve (TAV) (n = 23), both without and with (>44 mm) dilatation were investigated histologically and immunohistochemically for the expression of markers for vascular remodelling [transforming growth factor (TGF)-β, phosphorylated Smad2, matrix metalloproteinase 9 (MMP9)], cellular differentiation [c-Kit, phosphorylated-c-Kit, hypoxia-inducable factor-1 alpha (HIF1α)] and haemodynamic influences on the aortic wall [endothelial nitric oxide (eNOS)].

RESULTS

All BAV patients showed significantly less inflammation (P < 0.001) and an altered intima/media ratio when compared with TAV patients. The expression of markers of a signalling pathway characteristic for cellular dedifferentiation, as exemplified by the marked expression of c-Kit, phosphorylated c-Kit and HIF1α; in the dilated BAV group was however completely comparable with only a subgroup of the non-dilated BAV (BAb), whereas the remainder of the non-dilated BAV group (BAa) was significantly distinct. This difference between the dilated BAV and BAa was further confirmed in the expression of TGF-β, phosphorylated Smad2, MMP9 and eNOS. Besides the expression pattern, similarity in the dilated BAV and BAb was also noted clinically in the most common variant of commissure position and conjoined raphe of the BAV. Based on these observations, we consider the BAb group a likely candidate for future dilatation as opposed to the BAa group.

CONCLUSIONS

Using a panel of molecular tissue markers, the non-dilated BAV patients can be divided into groups susceptible and non-susceptible to aortopathy.

Aortic valve sclerosis in mice deficient in endothelial nitric oxide synthase

Risk factors for fibrocalcific aortic valve disease (FCAVD) are associated with systemic decreases in bioavailability of endothelium-derived nitric oxide (EDNO). In patients with bicuspid aortic valve (BAV), vascular expression of endothelial nitric oxide synthase (eNOS) is decreased, and eNOS(-/-) mice have increased prevalence of BAV. The goal of this study was to test the hypotheses that EDNO attenuates profibrotic actions of valve interstitial cells (VICs) in vitro and that EDNO deficiency accelerates development of FCAVD in vivo. As a result of the study, coculture of VICs with aortic valve endothelial cells (vlvECs) significantly decreased VIC activation, a critical early phase of FCAVD. Inhibition of VIC activation by vlvECs was attenuated by N(G)-nitro-l-arginine methyl ester or indomethacin. Coculture with vlvECs attenuated VIC expression of matrix metalloproteinase-9, which depended on stiffness of the culture matrix. Coculture with vlvECs preferentially inhibited collagen-3, compared with collagen-1, gene expression. BAV occurred in 30% of eNOS(-/-) mice. At age 6 mo, collagen was increased in both bicuspid and trileaflet eNOS(-/-) aortic valves, compared with wild-type valves. At 18 mo, total collagen was similar in eNOS(-/-) and wild-type mice, but collagen-3 was preferentially increased in eNOS(-/-) mice. Calcification and apoptosis were significantly increased in BAV of eNOS(-/-) mice at ages 6 and 18 mo. Remarkably, these histological changes were not accompanied by physiologically significant valve stenosis or regurgitation. In conclusion, coculture with vlvECs inhibits specific profibrotic VIC processes. In vivo, eNOS deficiency produces fibrosis in both trileaflet and BAVs but produces calcification only in BAVs.

Screening of families of patients with left-sided cardiovascular anomalies

BACKGROUND

There is increasing evidence of clustering of certain cardiac anomalies in some families. The frequency and echocardiographic features of such anomalies among the relatives of patients with bicuspid aortic valve (BAV) or other left-sided cardiovascular anomalies (LSCA) were evaluated.

METHODS

The patients with BAV or any other LSCA and their relatives were enrolled in the study. They underwent an echocardiographic examination. The probands were assessed in three groups: BAV, BAV + coarctation of aorta (CoA), and other LSCA. Their relatives were also grouped and evaluated accordingly. The echocardiographic measurements were standardized by Z-scores.

RESULTS

Eighty-six probands and 261 relatives were evaluated. The numbers of the patients in the BAV, BAV + CoA, and other LSCA group were 52, 14, and 20, respectively. Any LSCA was determined in 17 (6.5%) of the relatives. Thirteen (5%) had aortic dilatation and the remainder (1.5%) had BAV. Accordingly, BAV incidence among relatives of patients with BAV was found to be 1.9%. A second individual with an LSCA was observed in 12.8% of 86 families investigated. The frequencies of aortic stenosis, aortic regurgitation, aortic stenosis + aortic regurgitation, and aortic dilatation in the patients with BAV were found to be 37.9%, 53%, 25.8% and 48.5%, respectively. In contrast to previous reports, no enlargement was observed in the pulmonary arteries of BAV patients.

CONCLUSIONS

BAV and other LSCA are of clinical significance. Because the clustering of LSCA in some families is observed, we recommend echocardiographic screening of those relatives. If this is not possible, at least it should be achieved for BAV patients.

Bicuspid aortic valve disease and ascending aortic aneurysms: gaps in knowledge

The bicuspid aortic valve is the most common congenital cardiac anomaly in developed nations. The abnormal bicuspid morphology of the aortic valve results in valvular dysfunction and subsequent hemodynamic derangements. However, the clinical presentation of bicuspid aortic valve disease remains quite heterogeneous with patients presenting from infancy to late adulthood with variable degrees of valvular stenosis and insufficiency and associated abnormalities including aortic coarctation, hypoplastic left heart structures, and ascending aortic dilatation. Emerging evidence suggests that the heterogeneous presentation of bicuspid aortic valve phenotypes may be a more complex matter related to congenital, genetic, and/or connective tissue abnormalities. Optimal management of patients with BAV disease and associated ascending aortic aneurysms often requires a thoughtful approach, carefully assessing various risk factors of the aortic valve and the aorta and discerning individual indications for ongoing surveillance, medical management, and operative intervention. We review current concepts of anatomic classification, pathophysiology, natural history, and clinical management of bicuspid aortic valve disease with associated ascending aortic aneurysms.

Bicuspid aortic valve and thoracic aortic aneurysm: three patient populations, two disease phenotypes, and one shared genotype

Bicuspid aortic valve (BAV) and thoracic aortic aneurysm (TAA) are two discrete cardiovascular phenotypes characterized by latent progressive disease states. There is a clear association between BAV and TAA; however the nature and extent of this relationship is unclear. There are both distinct and overlapping developmental pathways that have been established to contribute to the formation of the aortic valve and the aortic root, and the mature anatomy of these different tissue types is intimately intertwined. Likewise, human genetics studies have established apparently separate and common contributions to these clinical phenotypes, suggesting complex inheritance and a shared genetic basis and translating 3 patient populations, namely, BAV, TAA, or both, into a common but diverse etiology. A better understanding of the BAV-TAA association will provide an opportunity to leverage molecular information to modify clinical care through more sophisticated diagnostic testing, improved counseling, and ultimately new pharmacologic therapies.

Bicuspid aortic valve and aortic root disease

Bicuspid aortic valve (BAV) is the most common form of congenital heart disease, with frequent and premature occurrence of cardiac events, dominated by significant valvular dysfunction. BAV has a high prevalence of aortic wall abnormalities such as ascending aortic dilatation. Because more rapid aortic dilatation can occur, once the ascending aorta reaches 40 mm, annual imaging with echocardiography or other imaging techniques is indicated. The most feared complication is aortic dissection. However, the actual incidence of this complication is low (4%). Although limited data exist regarding prophylactic intervention, it is suggested that elective surgical repair of BAV-associated aortic dilatation should be more aggressively recommended. In patients with BAV, the decision to indicate surgical treatment in aortic diameters between 50 and 55 mm should be based on patient age, body size, comorbidities, type of surgery, and the presence of additional risk factors.

Surgical management of life threatening events caused by intermittent aortic insufficiency in a native valve: case report

We describe a case of a patient admitted with apparent life threatening events characterized by hypotension and bradycardia. The patient was ultimately found to have intermittent severe aortic insufficiency. Upon surgical exploration, abnormalities were discovered in the aortic valve, which had a small left coronary cusp with absence of the nodulus of Arantius. Following surgical repair of the valve, aimed at preventing the small cusp from becoming stuck in the open position, the patient has remained episode free for over one year.

Bicuspid aortic valve disease

Bicuspid aortic valve (BAV) disease is the most common congenital cardiac defect. While the BAV can be found in isolation, it is often associated with other congenital cardiac lesions. The most frequent associated finding is dilation of the proximal ascending aorta secondary to abnormalities of the aortic media. Changes in the aortic media are present independent of whether the valve is functionally normal, stenotic, or incompetent. Although symptoms often manifest in adulthood, there is a wide spectrum of presentations ranging from severe disease detected in utero to asymptomatic disease in old age. Complications can include aortic valve stenosis or incompetence, endocarditis, aortic aneurysm formation, and aortic dissection. Despite the potential complications, 2 large contemporary series have demonstrated that life expectancy in adults with BAV disease is not shortened when compared with the general population. Because BAV is a disease of both the valve and the aorta, surgical decision making is more complicated, and many undergoing aortic valve replacement will also need aortic root surgery. With or without surgery, patients with BAV require continued surveillance. Recent studies have improved our understanding of the genetics, the pathobiology, and the clinical course of the disease, but questions are still unanswered. In the future, medical treatment strategies and timing of interventions will likely be refined. This review summarizes our current understanding of the pathology, genetics, and clinical aspects of BAV disease with a focus on BAV disease in adulthood.

The presence of bicuspid aortic valve does not predict ventricular septal defect type

Previous studies have identified an increased incidence of bicuspid aortic valve (BAV) in patients with ventricular septal defect (VSD). Because endocardial cushion remodeling contributes to both the formation of semilunar valves and ventricular septation, we hypothesized that examination of humans with BAV and VSD would identify a specific VSD type. We evaluated VSD type in pediatric patients diagnosed with BAV and VSD (n=82) and compared findings to patients diagnosed with VSD and normal aortic valve morphology (n=429). VSD type was described as conoventricular, muscular, inlet or conoseptal using a clinical taxonomy. Based on the contribution of the outflow tract endocardial cushions to the membranous ventricular septum, we expected patients with BAV to have conoventricular VSD. In both patient groups, conoventricular VSD was most common; however, the prevalence was not significantly different when BAV patients were compared to those with normal aortic valve morphology (67% vs. 57%, P=0.11). The primary finding of this study is that despite a developmental link between semilunar valve formation and ventricular septation during cardiogenesis, there is no clear association between BAV and VSD type. This may be due to phenotypic and genetic heterogeneity of BAV and VSD, other modifying factors as manifested by differences in associated CVM, as well as limitations of the clinical taxonomy of VSD.

Relation of coarctation of the aorta to the occurrence of ascending aortic dilation in children and young adults with bicuspid aortic valves

Children with bicuspid aortic valve (BAV) have aortic dilation that is present and progressive from birth irrespective of the functional state of the valve. There are no published data comparing aortic dilation in children with BAV with and without aortic coarctation (CoA). The objectives of this study were to (1) compare differences in aortic dimensions and rates of dilation between children with isolated BAV with those of children with BAV and CoA and (2) identify risk factors for the development of aortic dilation. Patients with BAV with CoA (group A) and without CoA (group B) were identified from our echocardiographic database (1993 to 2006). Aortic measurements at 4 levels were obtained, and z scores were compared. Criteria for exclusion were severe aortic regurgitation/stenosis, previous aortic valvuloplasty, complex left-sided cardiac disease, ventricular septal defects, and Turner, Noonan, Williams, and Marfan syndromes. There were 600 echocardiograms in 247 patients. Group A had 192 echocardiograms in 53 patients (median age 11.3 years; range 0 to 30; median follow-up 7 years), and group B had 382 in 194 patients (median age 8.7 years; range 0 to 29; median follow-up 4 years). Group B had significantly greater ascending aorta dimensions (p<0.05) and significantly faster rates of aortic dilation (p<0.0001). The ascending aorta in patients with BAV and CoA did not dilate to the same degree as in patients with isolated BAV. In conclusion, valve morphologic characteristics and function and age at CoA repair had none to minimal impact on aortic dimensions.

Is aortic wall degeneration related to bicuspid aortic valve anatomy in patients with valvular disease?

OBJECTIVE

Patients with bicuspid aortic valve are at increased risk for aortic complications.

METHODS

A total of 115 consecutive patients with bicuspid aortic valve disease underwent surgery of the ascending aorta. We classified the cusp configuration by 3 types: fusion of left coronary and right coronary cusps (type A), fusion of right coronary and noncoronary cusps (type B), and fusion of left coronary and noncoronary cusps (type C). Histopathologic changes in the ascending aortic wall were graded (aortic wall score).

RESULTS

We observed type A fusion in 85 patients (73.9%), type B fusion in 28 patients (24.3%), and type C fusion in 2 patients (1.8%). Patients with type A fusion were younger at operation than patients with type B fusion (51.3 +/- 15.5 years vs 58.7 +/- 7.6 years, respectively; P = .034). The mean ascending aorta diameter was 48.9 +/- 5.0 mm and 48.7 +/- 5.7 mm in type A and type B fusion groups, respectively (P = .34). The mean aortic root diameter was significantly larger in type A fusion (4.9 +/- 6.7 mm vs 32.7 +/- 2.8 mm; P < .0001). The aortic wall score was significantly higher in type A fusion than in type B fusion (P = .02). The prevalence of aortic wall histopathologic changes was significantly higher in type A fusion. Moreover, there were no statistically significant differences between type A and type B fusion in terms of prevalence of bicuspid aortic valve stenosis, regurgitation, or mixed disease.

CONCLUSION

In diseased bicuspid aortic valves, there was a statistically significant association between type A valve anatomy and a more severe degree of wall degeneration in the ascending aorta and dilatation of the aortic root at younger age compared with type B valve anatomy.

Aortic valve disease in Turner syndrome

OBJECTIVES

Our goal was to determine the prevalence and characteristics of aortic valve disease in girls and women with monosomy for the X chromosome, or Turner syndrome (TS).

BACKGROUND

Complications from congenital aortic valve disease are a major source of premature mortality in TS, but accurate data on the prevalence of aortic valve abnormalities and their association with aortic root dilation are not available.

METHODS

This prospective study characterized the aortic valve and proximal aorta in 253 individuals with TS age 7 to 67 years using transthoracic echocardiography as our primary screening tool, supplemented with magnetic resonance imaging.

RESULTS

Transthoracic echocardiography revealed a normal tricuspid aortic valve (TAV) in 172 and a bicuspid aortic valve (BAV) in 66 subjects. Transthoracic echocardiography could not visualize the aortic valve in 15 of 253 or 6%. Magnetic resonance imaging diagnosed 12 of 15 of these cases (8 BAV and 4 TAV), so that only 3 of 253 (1.2%) could not be visualized by either modality. The aortic valve was bicuspid in 74 of 250 (30%) adequately imaged subjects. The prevalence was equal in pediatric (<18 years, n = 89) and adult populations. Over 95% of abnormal aortic valves in TS resulted from fusion of the right and left coronary leaflets. Ascending aortic diameters were significantly greater at the annulus, sinuses, sinotubular junction, and ascending aorta in the BAV group, with aortic root dilation in 25% of subjects with BAV versus 5% of those with TAV.

CONCLUSIONS

Girls and women with TS need focused screening of the aortic valve and root to identify the many asymptomatic individuals with abnormal valvular structure and/or aortic root dilation.