New insights in the association between bicuspid aortic valve phenotype, aortic configuration and valve haemodynamics

Mechanisms of Aortic Dilation in Patients With Bicuspid Aortic Valve: JACC State-of-the-Art Review

Bicuspid aortic valve is the most common congenital heart disease and exposes patients to an increased risk of aortic dilation and dissection. Aortic dilation is a slow, silent process, leading to a greater risk of aortic dissection. The prevention of adverse events together with optimization of the frequency of the required lifelong imaging surveillance are important for both clinicians and patients and motivated extensive research to shed light on the physiopathologic processes involved in bicuspid aortic valve aortopathy. Two main research hypotheses have been consolidated in the last decade: one supports a genetic basis for the increased prevalence of dilation, in particular for the aortic root, and the second supports the damaging impact on the aortic wall of altered flow dynamics associated with these structurally abnormal valves, particularly significant in the ascending aorta. Current opinion tends to rule out mutually excluding causative mechanisms, recognizing both as important and potentially clinically relevant.

Unicuspid Aortic Valve in Patients Undergoing the Ross Procedure

BACKGROUND

The prevalence and outcomes of the unicuspid aortic valve (UAV) in patients undergoing the Ross procedure have been strongly underreported in the current literature. We sought to evaluate this in comparison with bicuspid (BAV) and tricuspid valve (TAV) in our Ross cohort.

METHODS

This was a retrospective observational study of patients undergoing the Ross procedure at 2 dedicated centers between 2009 and 2020. Primary end points were the risks of midterm autograft reoperation and the onset of at least moderate aortic regurgitation during follow-up. The secondary end point was to compare the perioperative outcomes between the groups.

RESULTS

Included in the analysis were 286 patients, of those 39% with UAV, 52% with BAV, and 9% with TAV. UAV patients were operated on at the youngest age (P < .001) and more often for a combined hemodynamic aortic valve pathology (P = .02). They had the largest aortic root dimensions: annulus (P = .01), Valsalva sinuses (P = .11), sinotubular junction (P = .001), and ascending aorta (P < .0001). The risks of reoperation (P = .86) and the onset of aortic regurgitation (P = .75) were comparable among the groups over the follow-up of 4.1 years. There was no difference in perioperative outcomes.

CONCLUSIONS

UAV is a separate unit characterized by a distinct hemodynamic pathology and generated aortopathy. It is not associated with a higher risk of reoperation or new onset of aortic regurgitation after the Ross procedure in the midterm postoperatively. At the current state, UAV remains acceptable for the Ross procedure.

The Impact of Bicuspid Aortic Valve Leaflet Fusion Morphology on the Ascending Aorta and on Outcomes of Aortic Valve Replacement

BACKGROUND

Patients with bicuspid aortic valves (BAVs) tend to develop dilation of the ascending aorta. The aim of this study was to analyze the impact of leaflet fusion pattern on aortic root diameter and outcomes in patients undergoing surgery for BAV vs tricuspid aortic valve (TAV) disease.

METHODS

This is a retrospective review of 90 patients with aortic valve disease (mean [SD] age, 51.5 [8.2] years) who underwent aortic valve replacement for BAV (n = 60) and TAV (n = 30). Fusion of right-left (R/L) coronary cusps was identified in 45 patients, whereas the remaining 15 patients had right-noncoronary (R/N) cusp fusion. Aortic diameter was measured at 4 levels, and Z values were computed.

RESULTS

There were no significant differences between the BAV and TAV groups for age, weight, aortic insufficiency grade, or size of implanted prostheses. However, a higher preoperative peak gradient at the aortic valve was significantly associated with R/L fusion (P = .02). Preoperative Z values of ascending aorta and sinotubular junction diameter were significantly higher in patients with R/N fusion than with the R/L (P < .001 and P = .04, respectively) and TAV (P < .001 and P < .05, respectively) subgroups. During the follow-up period (mean [SD], 2.7 [1.8] years), 3 patients underwent a redo procedure. At the last follow-up, the sizes of ascending aorta were similar among all 3 patient groups.

CONCLUSION

This study suggests that preoperative dilation of the ascending aorta is more common in patients with R/N fusion than in patients with R/L and TAV but is not significantly different between all groups in the early follow-up period. R/L fusion was associated with an increased risk of preoperative presence of aortic stenosis.

Is this the final answer for the aortopathy with bicuspid aortic valve

There have been changes in the guidelines for surgical indications for aortopathy associated with bicuspid aortic valves over the last 10 years. Although the results of the last 3 years adhering to the latest guidelines have been shown to be good, careful follow-up and accumulation of new research findings are still required.

Bicuspid Valve Sizing for Transcatheter Aortic Valve Implantation: The Missing Link

Transcatheter aortic valve implantation (TAVI) is a well-recognized and established therapy for severe aortic stenosis, with expanding indications toward younger patients with low surgical risk profile. As bicuspid aortic valve (BAV) affects ~1-2% of the population, it may be speculated that an increasing number of patients with degenerated BAV may eventually need TAVI during the course of the disease. On the other hand, BAV represents a challenge due to its peculiar anatomical features and the lack of consensus on the optimal sizing strategy. The aim of this paper is to review the peculiar aspects of BAV and to discuss and compare the currently available sizing methods. Special attention is given to the role of pre-procedural imaging, mostly with multislice computed tomography, and to the aspects that operators should evaluate in order to ensure an optimal procedural planning and avoid procedural-related complications.

Medial tunica degeneration of the ascending aortic wall is associated with specific microRNA changes in bicuspid aortic valve disease

Ascending aortic diameter is not an accurate parameter for surgical indication in patients with bicuspid aortic valve (BAV). Thus, the present study aimed to identify specific microRNAs (miRNAs/miRs) and their expression levels in aortic wall aneurysm associated with BAV according to severity of medial degeneration and to elucidate the association between the tissue expression levels of the miRNAs with their expression in plasma. Aortic wall and blood specimens were obtained from 38 patients: 12 controls and 26 patients with BAV with ascending aortic aneurysm. Of the patients with BAV, 19 had cusp fusions of right and left, 5 of right and non-coronary, and 2 of left and non-coronary. Two groups of patients were identified according to the grade of medial degeneration (MD): Low-grade D group (LGMD) and high-grade MD group (HGMD). Expression level of miR-122, miR-130, miR-718 and miR-486 were validated by reverse transcription-quantitative PCR in plasma and tissue samples. MD grade was found to be independent from the BAV phenotype. The HGD group showed increased expression levels of MMP-9 and MMP-2, and an increase in the number of apoptotic cells. Tissue expression levels of miR-718 and miR-122 were lower in the LGMD and HGD groups compared with expression in the control group; the HGD group showed increased levels of miR-486. Plasma expression levels of miR-122 were decreased in the LGMD and HGD groups, and miR-718 was only reduced in the HGD group. On the contrary, expression of miR-486 was increased in the LGMD and HGD groups. The data suggested that miR-486 may be considered as a non-invasive biomarker of aortic wall degeneration. Dysregulation of this putative biomarker may be associated with high risk of dissection and rupture in patients with BAV.

Valve disease and aortopathy associations of bicuspid aortic valve phenotypes differ between men and women

Objective

Determine whether associations between bicuspid aortic valve (BAV) phenotypes, valve disease and aortopathy differ between sexes.

Methods

1045 patients with BAV (76.0% men, n=794) from two surgical centres were included in this cross-sectional study. Valve phenotype was classified intraoperatively as right–left (RL), right-non-coronary (RN), left-non-coronary (LN) or 2-sinus BAV. Echocardiography was used to determine type and degree of valve disease, and aortic dimensions. Aortic dilatation was defined as diameter ≥4.5 cm.

Results

RL was the most common phenotype (73.6%), followed by RN (16.2%), 2-sinus BAV (9.2%) and LN (1.1%), with no difference in phenotype distribution between men and women (p=0.634). Aortic valve insufficiency (AI) prevalence differed significantly with valve phenotype in men (p=0.047), with RL and LN having the highest prevalence (34.1% and 44.0%, respectively). In women, RN had a higher proportion of AI than RL (21.3% vs 7.3%, p=0.017). Men with RL had larger root dimensions, in particular at the sinus (mean difference 0.24 cm compared with RN, p=0.002). Men with 2-sinus BAV had the highest prevalence of root phenotype dilatation (7.0%, other phenotypes ≤2.3%, p=0.031), whereas women with 2-sinus BAV did not have root dilatation and smaller sinus dimensions (mean difference: 0.35 cm compared with RL, p=0.021). Aortic root segments were larger in men with AI compared with aortic stenosis (sinus mean difference: 0.40 cm, p<0.001). The difference was even larger in women (mean difference: 0.78 cm, p<0.001), and women with AI also had larger tubular segments (mean difference: 0.61 cm, p=0.001).

Conclusions

There are significant sex differences in clinical associations of BAV phenotypes, which should be considered in further studies on the role of phenotypes in individualised patient management.

Aortic root aortopathy in bicuspid aortic valve associated with high genetic risk

Background

The bicuspid aortic valve (BAV) is prone to ascending aortic dilatation (AAD) involving both the tubular segment and the aortic root. The genetic factor was proposed as one of the most important mechanisms for AAD. We hypothesized that the rare genetic variants mainly contribute to the pathogenesis of aortic roots in affected individuals.

Methods

The diameter of aortic root or ascending aorta ≥ 40 mm was counted as AAD. The targeted next-generation sequencing of 13 BAV-associated genes were performed on a continuous cohort of 96 unrelated BAV patients. The rare variants with allele frequency < 0.05% were selected and analyzed. Variants frequency was compared against the Exome aggregation consortium database. The pathogenicity of the genetic variants was evaluated according to the American College of Medical Genetics and Genomics guidelines.

Results

A total of 27 rare nonsynonymous coding variants involving 9 genes were identified in 25 individuals. The burden analysis revealed that variants in GATA5, GATA6, and NOTCH1 were significantly associated with BAV. Eighty percent of the pathogenic variants were detected in root group. The detection rate of rare variants was higher in root dilatation group (71.4%) compared with normal aorta (29.0%) and tubular dilatation groups (29.6%) (P = 0.018). The rare variant was identified as the independent risk factor of root dilatation [P = 0.014, hazard ratio = 23.9, 95% confidence interval (1.9–302.9)].

Conclusions

Our results presented a broad genetic spectrum in BAV patients. The rare variants of BAV genes contribute the most to the root phenotype among BAV patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12872-021-02215-y.

Sex Differences in Children and Young Adults With Bicuspid Aortic Valve Disease in First Two Decades of Life

OBJECTIVE

To elucidate sex differences in valve morphology, disease phenotype, progression, and outcomes among children and young adults with bicuspid aortic valve (BAV).

PATIENTS AND METHODS

This is a retrospective cohort study examining all children and young adults (aged ≤22 years) with isolated BAV diagnosed, by excluding patients with concomitant congenital heart defects or genetic syndromes, from January 1, 1990, through December 1, 2016, at Mayo Clinic in Rochester, Minnesota.

RESULTS

Of 1010 patients with BAV, 558 had isolated BAV. Distributions of morphology were right-left in 65.8% (n=367), right-noncoronary in 34% (n=190), and left-noncoronary cusp fusion in 0.2% (n=1) of patients; with no sex differences. Male to female ratio was 3:1. At the first echocardiographic evaluation in the study, there were no sex differences in terms of frequency of aortic valve stenosis or regurgitation. However, males had significantly higher grades of aortic valve regurgitation at 17 years of age onward (P<.0001). Males had significantly larger mid-ascending aorta (P=.01) and sinus of Valsalva dimensions (z score; P=.0001) as compared with females, with a novel finding of peak aortic dimensions around 8 years of age. Males also had more than 2-fold higher risk for sinus of Valsalva dilation (z score >2) as compared with females (odds ratio, 2.3; 95% CI, 1.2 to 4.2; P=.01). There were no significant sex differences in the primary cardiac outcomes of interventions on aortic valve and/or aorta, aortic dissection, or death.

CONCLUSION

In children and young adults with BAV, males have a higher grade of aortic regurgitation in late adolescence, significantly larger aortic dimensions, different patterns of aortic growth, and more frequent sinus of Valsalva dilation as compared with females. Overall, the rate of primary cardiac events is lower in young patients, with no significant sex differences.

Non-aneurysmal ascending aorta diameter changes after aortic valve replacement in patients with stenotic bicuspid and tricuspid aortic valve

OBJECTIVE

The appropriate timing of aortic repair in patients with bicuspid aortic valve-related aortopathy remains controversial. We describe the changes in diameter of the non-aneurysmal ascending aorta after aortic valve replacement for bicuspid or tricuspid aortic valve stenosis.

METHODS

This retrospective review included 189 patients who had undergone aortic valve replacement for severe stenotic aortic valve with a non-aneurysmal ascending aorta diameter of 45 mm or less between January 2008 and December 2018. A linear mixed-effect model was used to analyze and compare the enlargement rates of the non-aneurysmal ascending aorta at the tubular portion after aortic valve replacement in bicuspid and tricuspid aortic valve patients.

RESULTS

The enlargement rate of the non-aneurysmal ascending aorta after aortic valve replacement was significantly greater in the bicuspid aortic valve group than in the tricuspid aortic valve group (0.36 mm/year vs. 0.09 mm/year, p < 0.001). The specific form of bicuspid aortic valve also affected aorta diameter enlargement: the enlargement rate of 0.85 mm/year in the Type 0 (according to Sievers' classification) group was approximately five times that in the Non-Type 0 group (p < 0.001). No aortic events were observed, and no patients needed reoperations for the ascending aorta, in either the bicuspid or tricuspid aortic valve groups.

CONCLUSION

The persistent possibility of progressive ascending aortic dilatation after aortic valve replacement for bicuspid aortic valve stenosis, especially in Type 0 bicuspid aortic valve patients, demands careful post-procedural evaluation of the ascending aorta.

Considerations in the Surgical Management of Unicuspid Aortic Stenosis

Unicuspid aortic valve (UAV) stenosis is a rare condition accounting for 5% of non-rheumatic aortic stenosis. The diagnosis can be difficult to make prior to surgical intervention and transesophageal echocardiography has been demonstrated to be more accurate in making the diagnosis compared to transthoracic echocardiography. The presence of a posteriorly located aortic orifice on the short-axis views, with one or two visible raphe anteriorly; the absence of commissures (acommissural); or the presence of a lone commissure (unicommissural) between the left and noncoronary, or the left and right cusps suggests the diagnosis. Patients with UAV are predominantly males and present with stenosis about a decade earlier than those with the more prevalent bicuspid aortic valves (BAV). They more commonly present with aortic annular dilatation and have fewer comorbidities at presentation compared to patients with BAV. Surgical management of UAV stenosis includes aortic valve replacement through standard open heart surgery or percutaneous transcatheter aortic valve replacement (TAVR), aortic valve repair either by bicuspidization, tricuspidization or trileaflet reconstruction, or the Ross procedure. Patients with UAV stenosis require less concomitant coronary or other cardiac procedures when they need surgical intervention, but are about a decade younger at the time of their death. UAV stenosis is a distinct congenital anomaly with a different natural course than BAV. Surgical management should be individualized based on the patient's age at presentation, aortoannular anatomy, and associated cardiac conditions.

Echocardiographic assessment of aortic stenosis: a practical guideline from the British Society of Echocardiography

The guideline provides a practical step-by-step guide in order to facilitate high-quality echocardiographic studies of patients with aortic stenosis. In addition, it addresses commonly encountered yet challenging clinical scenarios and covers the use of advanced echocardiographic techniques, including TOE and Dobutamine stress echocardiography in the assessment of aortic stenosis.

Bicuspid aortic valve disease - the influence of valve morphotype on age at and types of surgical treatment

Background

Patients with bicuspid aortic valve (BAV) with zero or two raphes have been under-represented in previous studies. Whether these patients have unique clinical courses remains unclear. We describe the indications for and types of surgery in patients with BAV, and describe differences between valve morphotypes.

Methods

Adults who had undergone aortic and/or aortic valve surgery for BAV disease at our centres were identified and classified according to the Sievers definitions.

Results

317 patients were included (74.4% male, median age at surgery 62 years). Of these, 187 (59.0%) had aortic valve surgery, 7 (2.2%) aortic surgery, 120 (37.9%) combined valve and aortic surgery and 3 had a Ross procedure. Most patients had aortic stenosis (71.9%), followed by aortic regurgitation (16.7%). 30-day mortality was low (1.6%).

The commonest valve morphology was type-1 (one raphe) in 89.6%; type-0 (no raphes) occurred in 7.9% and type-2 (two raphes) in 2.5%. Patients with type-2 valves were substantially younger at time of surgery than type-1 patients (median 36 vs 63 years, p = 0.008). A higher proportion of patients with type-0 valves required aortic surgery than those with type-1 (68.0% vs 37.3%, p = 0.007). There were no differences between groups for the indication for surgery, valvular abnormality or 30-day mortality.

Conclusions

The number of BAV raphes was independently and significantly associated with age at surgery and the need for aortic intervention. Patients with type 0 and type 2 valves are a small but important proportion of the BAV population, potentially requiring different clinical surveillance and management.

Bicuspid Aortic Valve: Morphology, Clinic, Diagnosis, Complications

Bicuspid aortic valve refers to common (0.5-2% of the population) congenital heart defects that are asymptomatic throughout life, with valve dysfunction and/or aortopathy (pathia- from Greek pathos disease), manifested by expansion, aneurysm or dissection of the vessel. The pathogenesis of the formation of a bicuspid valve is unknown, a genetic component is noted, since the defect develops as sporadic, familial, in combination with other congenital heart defects and with hereditary connective tissue disorders. Morphogenetic studies suggest that different phenotypes of bicuspid aortic valve can be considered as etiologically different diseases, with valve dysfunction or valve dysfunction and aortopathy. Aortic lesion is characterized by phenotypic heterogeneity due to genetic or hemodynamic features. Researchers are discussing the relationship between the phenotype of the bicuspid aortic valve and aortopathy to predict the course of the disease and select the optimal surgical treatment technique. Diagnosis of heart disease is based on the results of an echocardiographic study, magnetic resonance imaging. Surgical treatment is performed for significant hemodynamic disturbances resulting from insufficiency or stenosis of the aortic valve, in cases of infective endocarditis, the risk of which is high, with aneurysm or aortic dissection.

Fate of mild-to-moderate bicuspid aortic valve disease untreated during ascending aorta replacement

BACKGROUND

Bicuspid aortic valve (BAV) is the most common congenital heart defect and it is responsible for an increased risk of developing aortic valve and ascending aorta complications. In case of mild to moderate BAV disease in patients undergoing supracoronary ascending aorta replacement, it is unclear whether a concomitant aortic valve replacement should be performed.

METHODS

From June 2002 to January 2020, 75 patients with mild-to-moderate BAV regurgitation (±mild-to-moderate stenosis) who underwent isolated supracoronary ascending aorta replacement were retrospectively analyzed. Clinical and echocardiographic follow-up was 100% complete (mean: 7.4 ± 3.9 years, max: 16.4). Kaplan-Meier estimates were employed to analyze long-term survival. Cumulative incidence function (CIF) for time to reoperation, recurrence of aortic regurgitation (AR) ≥3+ and aortic stenosis (AS) greater than moderate, with death as competing risk, were computed.

RESULTS

There was no hospital mortality and no cardiac death occurred. Overall survival at 12 years was 97.4 ± 2.5%, 95% confidence interval (CI: 83.16-99.63). At follow-up there were no cases of aortic root surgery whereas three patients underwent AV replacement. At 12 years the CIF of reoperation was 2.6 ± 2.5%, 95% CI [0.20-11.53]. At follow-up, AR 3+/4+ was present in 1 pt and AS greater than moderate in 3. At 12 years the CIF of AR more than 2+/4+ was 5.1 ± 4.98% and of AS more than moderate 6.9 ± 3.8%.

CONCLUSIONS

In our study mild to moderate regurgitation of a BAV did not do significantly worse at least up to 10 years after isolated supracoronary ascending aorta replacement.

The Association between Morphological and Functional Characteristics of the Bicuspid Aortic Valve and Bicuspid Aortopathy

Objective

To identify the association between morphological and functional characteristics of the bicuspid aortic valve (BAV) and bicuspid aortopathy and to identify the determinants of aortic dilatation using transthoracic echocardiography (TTE) and cardiac computed tomography (CCT).

Materials and Methods

This study included 312 subjects (mean [SD] age, 52.7 [14.3] years; 227 males [72.8%]) who underwent TTE and CCT. The BAVs were classified by anterior-posterior (BAV-AP) or right-left (BAV-RL) orientation of the cusps and divided according to the presence (raphe+) or absence of a raphe (raphe−) based on the CCT and intraoperative findings. The dimensions of the sinus of Valsalva and the proximal ascending aorta were measured by CCT. We assessed the determinants of aortic root and proximal ascending aortic dilatation (size index > 2.1 cm/m²) by Univariable and multivariable logistic regression analyses.

Results

Of the 312 patients, BAV-AP was present in 188 patients (60.3%), and 185 patients (59.3%) were raphe+. Moderate-to-severe aortic stenosis (AS) was the most common hemodynamic abnormality (54.8%). The most common type of aortopathy was the combined dilated root and mid-ascending aortic phenotype (62.5%). On multivariable analysis, age and AS severity were significantly associated with aortic root dilatation (p < 0.05), and age, sex, and AS severity were significantly associated with ascending aortic dilatation (p < 005). However, the orientation of the cusps, presence of a raphe, and severity of aortic regurgitation were not associated with aortic root and ascending aortic dilatation.

Conclusion

BAV morphological characteristics were not determinants of aortic dilatation. Age, sex, and AS severity were predictors of bicuspid aortopathy. Therefore, age, sex, and AS severity, rather than valve morphology, need to be considered when planning treatment for BAV patients.

Prevalence of Bicuspid Aortic Valve and Associated Aortopathy in Newborns in Copenhagen, Denmark

IMPORTANCE

The prevalence and characteristics of bicuspid aortic valve (BAV) are mainly reported from selected cohorts. BAV is associated with aortopathy, but it is unclear if it represents a fetal developmental defect or is secondary to abnormal valve dynamics.

OBJECTIVE

To determine the prevalence of BAV and BAV subtypes and to describe the associated aortopathy in a large, population-based cohort of newborns.

DESIGN, SETTING, AND PARTICIPANTS

The Copenhagen Baby Heart Study was a cross-sectional, population-based study open to all newborns born in Copenhagen between April 1, 2016, and October 31, 2018. Newborns with BAV were matched 1:2 to newborns with a tricuspid aortic valve (non-BAV group) on sex, singleton/twin pregnancy, gestational age, weight, and age at time of examination.

EXPOSURES

Transthoracic echocardiography within 60 days after birth.

MAIN OUTCOMES AND MEASURES

Primary outcome was BAV prevalence and types, ie, number of raphes and spatial orientation of raphes or cusps (no raphes), according to the classification system of Sievers and Schmidtke (classified as type 0, 1, or 2, with numbers indicating the number of raphes). Secondary outcome was valve function and BAV-associated aortopathy, defined as aortic diameter z score of 3 or greater or coarctation.

RESULTS

In total, 25 556 newborns (51.7% male; mean age, 12 [SD, 8] days) underwent echocardiography. BAV was diagnosed in 196 newborns (prevalence, 0.77% [95% CI, 0.67%-0.88%]), with male-female ratio 2.1:1. BAV was classified as type 0 in 17 newborns (8.7% [95% CI, 5.5%-13.5%]), type 1 in 178 (90.8% [95% CI, 86.0%-94.1%]) (147 [75.0% {95% CI, 68.5%-80.5%}] right-left coronary raphe, 27 [13.8% {95% CI, 9.6%-19.3%}] right coronary-noncoronary raphe, 4 [2.0% {95% CI, 0.8%-5.1%}] left coronary-noncoronary raphe), and type 2 in 1 (0.5% [95% CI, 0.1%-2.8%]). Aortic regurgitation was more prevalent in newborns with BAV (n = 29 [14.7%]) than in those without BAV (1.3%) (absolute % difference, 13.4% [95% CI, 7.8%-18.9%]; P < .001). Newborns with BAV had higher flow velocities across the valve (0.67 [95% CI, 0.65-0.69] m/s vs 0.61 [95% CI, 0.60-0.62] m/s; mean difference, 0.06 m/s [95% CI, 0-0.1]) and larger aortic root and tubular ascending aortic diameters than those without BAV (10.7 [95% CI, 10.7-10.9] mm vs 10.3 [95% CI, 10.2-10.4] mm; mean difference, 0.43 mm [95% CI, 0.2-0.6 mm] and 9.8 [95% CI, 9.6-10.0] mm vs 9.4 [95% CI, 9.3-9.5] mm; mean difference, 0.46 mm [95% CI, 0.30-0.70], respectively) (P < .001 for all). Aortopathy was seen in 65 newborns (33.2%) with BAV (62 with aortic z score ≥3; 3 with coarctation).

CONCLUSIONS AND RELEVANCE

Among newborns in Copenhagen, the prevalence of BAV was 0.77%. Aortopathy was common in newborns with BAV, suggesting that it also represents a fetal malformation.

Does the Leaflet Fusion Subtype Affect Pattern and Rate of Growth in BAV Aortopathy?: A Study of 102 BAV Aortopathy Cases With A Literature Review

BACKGROUND

Bicuspid aortic valves (BAV) and related aortopathy remain an intriguing topic. Not all BAVs get diseased and around 40% would develop aortic dilatation in their lifetime. If haemodynamic theory is to be believed, then leaflet fusion pattern should have an impact. This study sought to compare the association of aortic morphologies and rate of growth in a set of 102 BAV acropathies operated at a single centre, based on the fusion patterns.

METHODS

Data on aortic valve replacements over a 10-year period was analysed from a prospectively maintained database. Of the 198 BAV undergoing surgery, 102 had aortic dilatation above 40 mm on echocardiogram. These underwent computed tomography (CT) aortograms and were followed up as a part of a database. The impact of leaflet fusion patterns on aortic dilatation pattern and rate was analysed.

RESULTS

Of the 102, two patients had type 0 pathology and one had left-noncoronary (LN) leaflet fusion. Seventy-four (74) had type 1A or left-right (RL) fusion and 25 had type 1B right-noncoronary (RN) fusion. RL fusion had more males, were taller, bigger and had more proportion of aortic stenosis (AS). Aortic diameters, angles and growth rates at root, ascending/descending aorta and arch were not different. Regression analyses for size or growth did not show any significant impact of fusion pattern.

CONCLUSIONS

Left-right fusion pattern comprised three-quarters of BAV in this cohort and these patients were bigger, taller and had a greater proportion of males with increased rate of aortic stenosis. Despite these differences, there was no significant impact of fusion pattern on aortic size or rate of growth.

Biomechanical properties and histomorphometric features of aortic tissue in patients with or without bicuspid aortic valve

Background

We sought to investigate and compare biomechanical properties and histomorphometric findings of thoracic ascending aorta aneurysm (TAA) tissue from patients with bicuspid aortic valve (BAV) and tricuspid aortic valve (TAV) in order to clarify mechanisms underlying differences in the clinical course.

Methods

Circumferential sections of TAA tissue in patients with BAV (BAV-TAA) and TAV (TAV-TAA) were obtained during surgery and used for biomechanical tests and histomorphometrical analysis.

Results

In BAV-TAA, we observed biomechanical higher peak stress and lower Young modulus values compared with TAV-TAA wall. The right lateral longitudinal region seemed to be the most fragile zone of the TAA wall. Mechanical stress-induced rupture of BAV-TAA tissue was sudden and uniform in all aortic wall layers, whereas a gradual and progressive aortic wall breakage was described in TAV-TAA. Histomorphometric analysis revealed higher amount of collagen but not elastin in BAV-TAA tunica media.

Conclusions

The higher deformability of BAV-TAA tissue supports the hypothesis that increased wall shear stress doesn’t explain the increased risk of sudden onset of rupture and dissection; other mechanisms, likely related to alteration of specific genetic pathways and epigenetic signals, could be investigated to explain differences in aortic dissection and rupture in BAV patients.

Utilizing wall shear stress as a clinical biomarker for bicuspid valve-associated aortopathy

PURPOSE OF REVIEW

Bicuspid aortic valve (BAV) results from fusion of two adjacent aortic valve cusps, and is associated with dilatation of the aorta, known as BAV-associated aortopathy, or bicuspid aortopathy. Bicuspid aortopathy is progressive, increasing the risk of life-threatening clinical events, such as aortic dissection. Regular monitoring and timely intervention with prophylactic surgical resection of the proximal aorta is recommended.

RECENT FINDINGS

Aortopathy is heterogeneous among patients. Studies have shown that different flow patterns lead to specific phenotypes of aortopathy. Although not uniform, BAV morphology affects flow patterns. Recent work has demonstrated the role of wall shear stress (WSS) in driving aortopathy, and it is suggested that individualized WSS 'heat maps' can be used for clinically monitoring patients with BAV. WSS has the potential to be an imaging biomarker for directing resection timing, surgical strategies, and postsurgical follow-up care.

SUMMARY

Finding and validating noninvasive hemodynamic biomarkers of aortic risk to assist in the management of BAV patients is of clinical importance. Herein, we will review the latest findings pertaining to the utility of WSS as a specific biomarker of risk for BAV patients with aortopathy.

Determinants of aortic growth rate in patients with bicuspid aortic valve by cardiovascular magnetic resonance

Objectives

This study aimed to identify determinants of aortic growth rate in bicuspid aortic valve (BAV) patients. We hypothesised that (1) BAV patients with repaired coarctation (CoA) exhibit decreased aortic growth rate, (2) moderate/severe re-coarctation (reCoA) results in increased growth rate, (3) patients with right non-coronary (RN) valve cusps fusion pattern exhibit increased aortic growth rate compared with right-left cusps fusion and type 0 valves.

Methods

Starting from n=521 BAV patients with cardiovascular magnetic resonance data, we identified n=145 patients with at least two scans for aortic growth analysis. Indexed areas of the sinuses of Valsalva and ascending aorta (AAo) were calculated from cine images in end-systole and end-diastole. Patients were classified based on dilation phenotype, presence of CoA, aortic valve function and BAV morphotype. Comparisons between groups were performed. Linear regression was carried out to identify associations between risk factors and aortic growth rate.

Results

Patients (39±16 years of age, 68% male) had scans 3.7±1.8 years apart; 32 presented with AAo dilation, 18 with aortic root dilation and 32 were overall dilated. Patients with repaired CoA (n=61) showed decreased aortic root growth rate compared with patients without CoA (p≤0.03) regardless of sex or age. ReCoA, aortic stenosis, regurgitation and history of hypertension were not associated with growth rate. RN fusion pattern showed the highest aortic root growth rate and type 0 the smallest (0.30 vs 0.08 cm²/m*year, end-systole, p=0.03).

Conclusions

Presence of CoA and cusp fusion morphotype were associated with changes in rate of root dilation in our BAV population.

The American Association for Thoracic Surgery consensus guidelines on bicuspid aortic valve-related aortopathy: Full online-only version

Bicuspid aortic valve disease is the most common congenital cardiac disorder, being present in 1% to 2% of the general population. Associated aortopathy is a common finding in patients with bicuspid aortic valve disease, with thoracic aortic dilation noted in approximately 40% of patients in referral centers. Several previous consensus statements and guidelines have addressed the management of bicuspid aortic valve-associated aortopathy, but none focused entirely on this disease process. The current guidelines cover all major aspects of bicuspid aortic valve aortopathy, including natural history, phenotypic expression, histology and molecular pathomechanisms, imaging, indications for surgery, surveillance, and follow-up, and recommendations for future research. It is intended to provide clinicians with a current and comprehensive review of bicuspid aortic valve aortopathy and to guide the daily management of these complex patients.

The Heterogeneous Phenotype of Bicuspid Aortopathy Attribute to Different Dominant Pathogenesis

Purpose: Our study aimed to investigate the potential pathogenetic theories of different phenotype prevalence in bicuspid aortopathy.

Methods: A total of 407 bicuspid aortic valve (BAV) patients with aortic dilation were retrospectively reviewed. Association was determined between aortic valve lesion types and aortic configurations to confirm the homogeneous BAV subsets, and then, dominance analysis was used to evaluate the relative importance of two components of aortic valve lesion (BAV phenotype and valvular dysfunction) that associated with aortic configurations in each subgroup.

Results: Dominance analysis showed that Type-1 LR was the dominant contributor (79.0% and 79.6%) associated with the higher prevalence of the dilation of aortic root (AoR) and ascending aorta (AAo) in BAV patients with Type-1 LR and aortic regurgitation (AR) or aortic stenosis (AS) + AR. However, AS was the main contributor (60.0%) associated with the raised incidence of the dilation of AAo and proximal aortic arch (PArc) in Type-0 LAT and AS.

Conclusions: Different dominant pathogenetic theory determined the phenotype of BAV aortopathy. In patients of Type-1 LR with AR, inherent disposition is mainly responsible for the higher frequency of AoR dilation. Valve-related hemodynamics determined greater prevalence of the dilation of AAo and PArc in patients of Type-0 LAT with AS.

Risk Factors Associated with Ascending Aortic Aneurysms and Aortic Elasticity Parameters in Children with a Bicuspid Aortic Valve

Aneurysms of the ascending aorta are frequently found in patients with a bicuspid aortic valve (BAV). This study assessed the risk factors of ascending aortic aneurysms and aortic elasticity in children with BAV. The study included 66 patients with no history of transcatheter intervention or surgical procedure who had been diagnosed with isolated BAV. Echocardiographic, blood pressure, and pulse measurements were obtained for all patients. The BAVs were classified as described by Sievers et al. (J Thorac Cardiovasc Surg 133:1226-1233, 2007), and aortic elasticity parameters were calculated using various formulas. The patients were divided into groups with and without cusp fusion, aortic stenosis (AS), aortic regurgitation (AR), or mixed lesions; the groups were then compared. The mean patient age was 10.43 ± 3.91 years; 15%he patients had no AS or AR, 33% had both AS and AR, 17% had AS alone, and 35% had AR alone. The most common type of BAV was type 5, and the ascending aorta z-scores were higher in children with mixed lesions and without a cusp fusion. Aortic distensibility (AD) was significantly higher, and the stiffness index was significantly lower, in patients with an ascending aorta z-score > 4. The ascending aortic z-scores were higher in the no-fusion and mixed lesion (AS + AR) groups, especially those originating from post-stenotic dilation due to AS. The AD was increased in patients with an ascending aorta z-score > 4. Patients should thus be monitored closely for dissection risk, and preventive medical treatment should be started early in those with AS without cusp fusion.

Bicuspid aortic valve-associated aortopathy: Where do we stand?

Herein we summarize the current knowledge on the bicuspid aortic valve (BAV)-associated aortopathy regarding clinical presentation and disease sub-classification, genetic background, hemodynamics, histopathology, cells and signaling, animal models, and biomarkers. Despite enormous efforts in research in all of the above areas, important issues remain unknown: (i) what is the ontogenetic basis of BAV development? (ii) how can we explain the diversity of BAV and associated aortopathy phenotypes? (iii) what are the signaling processes in aortopathy pathogenesis and how can we interfere with these processes? Despite undoubtedly great progress that has been made in the understanding of BAV-associated aortopathy, so far researchers have put together a heap of Lego bricks, but at present it is unclear if the bricks are compatible, how they fit together, and which parts are missing to build the true model of the BAV aorta. A joint approach is needed to accelerate research progress.

Evolving Surgical Approaches to Bicuspid Aortic Valve Associated Aortopathy

Bicuspid aortic valve (BAV) is the most common congenital cardiac pathology which results from the fusion of two adjacent aortic valve cusps. It is associated with dilatation of the aorta, known as bicuspid valve-associated aortopathy or bicuspid aortopathy. Bicuspid aortopathy is progressive and is linked with adverse clinical events. Hence, frequent monitoring and early intervention with prophylactic surgical resection of the proximal aorta is often recommended. Over the past two decades resection strategies and surgical interventions have mainly been directed by surgeon and institution preferences. These practices have ranged from conservative to aggressive approaches based on aortic size and growth criteria. This strategy, however, may not best reflect the risks of important aortic events. A new set of guidelines was proposed for the treatment of bicuspid aortopathy. Herein, we will highlight the most recent findings pertinent to bicuspid aortopathy and its management in the context of a case presentation.

Bicuspid aortic valve formation: Nos3 mutation leads to abnormal lineage patterning of neural crest cells and the second heart field

The bicuspid aortic valve (BAV), a valve with two instead of three aortic leaflets, belongs to the most prevalent congenital heart diseases in the world, occurring in 0.5-2% of the general population. We aimed to understand how changes in early cellular contributions result in BAV formation and impact cardiovascular outflow tract development. Detailed 3D reconstructions, immunohistochemistry and morphometrics determined that, during valvulogenesis, the non-coronary leaflet separates from the parietal outflow tract cushion instead of originating from an intercalated cushion. Nos3^-/- mice develop a BAV without a raphe as a result of incomplete separation of the parietal outflow tract cushion into the right and non-coronary leaflet. Genetic lineage tracing of endothelial, second heart field and neural crest cells revealed altered deposition of neural crest cells and second heart field cells within the parietal outflow tract cushion of Nos3^-/- embryos. The abnormal cell lineage distributions also affected the positioning of the aortic and pulmonary valves at the orifice level. The results demonstrate that the development of the right and non-coronary leaflets are closely related. A small deviation in the distribution of neural crest and second heart field populations affects normal valve formation and results in the predominant right-non-type BAV in Nos3^-/- mice.

Aortic arch tortuosity, a novel biomarker for thoracic aortic disease, is increased in adults with bicuspid aortic valve

INTRODUCTION

Arterial tortuosity has emerged as a predictor of adverse outcomes in congenital aortopathies using 3D reconstructed images. We validated a new method to estimate aortic arch tortuosity on 2D CT. We hypothesize that arch tortuosity may identify bicuspid aortic valve (BAV) patients at high risk to develop thoracic aortic aneurysms or aortic dissections (TAD).

METHODS

BAV subjects with chest CT scans were retrospectively identified in our clinical records and matched to tricuspid aortic valve (TAV) controls by age, gender, and presentation with TAD. Subjects with prior ascending aortic intervention were excluded. Measurements included aortic arch tortuosity, length, angle, width and height. Total aortic tortuosity was estimated in subjects with available abdominal images.

RESULTS

120 BAV and 234 TAV subjects were included. Our 2D measurements were highly correlated with 3D midline arch measurements and had high inter- and intra-observer reliability. Compared to TAV, BAV subjects had increased arch tortuosity (median 1.76 [Q1-Q3: 1.62-1.95] vs. 1.63 [1.53-1.78], P < 0.01), length (149 [136-160] vs. 135 [122-152] mm, P < 0.01), height (46 [41-53] vs. 39 [34-47] mm, P < 0.01), and vertex acuity (70 [61-77] vs. 75 [68-81] degree, P < 0.01). In a multivariable analysis, arch tortuosity remained independently associated with BAV after adjusting for aortic diameter and other clinical characteristics.

CONCLUSIONS

We found that aortic arch tortuosity is significantly increased in BAV and may identify BAV patients who are at increased risk for TAD. Further studies to evaluate the association between tortuosity and clinical outcomes are in progress.

Epigenetic influences on genetically triggered thoracic aortic aneurysm

Genetically triggered thoracic aortic aneurysms (TAAs) account for 30% of all TAAs and can result in early morbidity and mortality in affected individuals. Epigenetic factors are now recognised to influence the phenotype of many genetically triggered conditions and have become an area of interest because of the potential for therapeutic manipulation. Major epigenetic modulators include DNA methylation, histone modification and non-coding RNA. This review examines epigenetic modulators that have been significantly associated with genetically triggered TAAs and their potential utility for translation to clinical practice.

Segmental aortic stiffness in patients with bicuspid aortic valve compared with first-degree relatives

Aims

To compare the stiffness index in patients with bicuspid aortic valve (BAV) with first-degree relatives at each segment of the thoracic ascending aorta and to compare segmental analysis of aortic stiffness in association with BAV morphotype and function.

Methods

219 patients with BAV and 148 first-degree relatives (without BAV) were consecutively included at a reference centre for BAV. Ultrasound assessment of aortic and carotid stiffness was based on the variation of the segmental arterial diameters during the cardiac cycle and on blood pressure.

Results

Without adjustment, the ascending aorta of patients with BAV seemed stiffer at each segment compared with controls (stiffness index at the sinus of Valsalva: 17.0±10.9 vs 8.9±6.1, p<0.001; tubular aorta: 20.4±31.3 vs 12.7±4.8, p=0.04). However, after adjustment on aortic diameter and age, only the sinus of Valsalva remained stiffer (p<0.001), whereas the tubular aorta no longer differed (p=0.610). In patients with BAV, aortic diameters were not influenced by the valve morphotype, except for the arch, which was more dilated in the case of 1- Non coronary sinus-Right subtype of BAV : 36.1 vs 27.6 mm, p<0.001. Aortic regurgitation was associated with an increase in aortic diameters at the sinus of Valsalva (p<0.001) and the tubular aortic levels (p=0.04).

Conclusion

Stiffness increase at the sinus of Valsalva level is independent of aortic dilatation in patients with BAV, contrary to the classic relationship between stiffness and dilatation found on the other segments. The relationship between stiffness and clinical impact needs to be assessed at each aortic segment.

Unicuspid Aortic Valve Presenting with Decompensated Critical Aortic Stenosis

•UAV is a rare congenital anomaly that leads to severe symptomatic stenosis.•Echocardiography plays a critical role in the evaluation of aortic stenosis.•Correctly distinguishing between UAV and BAV is relevant in determining intervention.

Threshold for intervention upon ascending aortic aneurysms: an evolving target and implication of bicuspid aortic valve

With the proliferation of non-invasive thoracic imaging modalities, the question of when to operate on asymptomatic ascending aortic aneurysms for non-syndromic patients is becoming increasingly relevant. Operation is extensive, often involves circulatory arrest, and subjects the patient to significant risk of mortality and morbidity. Surgery is performed to avert fatal aortic adverse events, which carry a markedly poor prognosis. The question of when the balance is tipped toward preemptive surgical repair is challenging and is centered around predicting the risk of an acute aortic syndrome. Size of the aneurysm has been the traditional guide for decision-making but how this is measured, what risks it truly predicts, the influence of the patient's size, valve morphology, genetic profile, and other risk factors for non-syndromic patients are poorly understood. We here review this issue in detail.

Enlightening the Association between Bicuspid Aortic Valve and Aortopathy

Bicuspid aortic valve (BAV) patients have an increased incidence of developing aortic dilation. Despite its importance, the pathogenesis of aortopathy in BAV is still largely undetermined. Nowadays, intense focus falls both on BAV morphology and progression of valvular dysfunction and on the development of aortic dilation. However, less is known about the relationship between aortic valve morphology and aortic dilation. A better understanding of the molecular pathways involved in the homeostasis of the aortic wall, including the extracellular matrix, the plasticity of the vascular smooth cells, TGFβ signaling, and epigenetic dysregulation, is key to enlighten the mechanisms underpinning BAV-aortopathy development and progression. To date, there are two main theories on this subject, i.e., the genetic and the hemodynamic theory, with an ongoing debate over the pathogenesis of BAV-aortopathy. Furthermore, the lack of early detection biomarkers leads to challenges in the management of patients affected by BAV-aortopathy. Here, we critically review the current knowledge on the driving mechanisms of BAV-aortopathy together with the current clinical management and lack of available biomarkers allowing for early detection and better treatment optimization.

Anatomical and clinical predictors of valve dysfunction and aortic dilation in bicuspid aortic valve disease

Objective

Bicuspid aortic valve (BAV) is associated with early valvular dysfunction and proximal aorta dilation with high heterogeneity. This study aimed to assess the determinants of these complications.

Methods

Eight hundred and fifty-two consecutive adults diagnosed of BAV referred from cardiac outpatient clinics to eight echocardiographic laboratories of tertiary hospitals were prospectively recruited. Exclusion criteria were aortic coarctation, other congenital disorders or intervention. BAV morphotype, significant valve dysfunction and aorta dilation (≥2 Z-score) at sinuses and ascending aorta were established.

Results

Three BAV morphotypes were identified: right–left coronary cusp fusion (RL) in 72.9%, right–non-coronary (RN) in 24.1% and left–non-coronary (LN) in 3.0%. BAV without raphe was observed in 18.3%. Multivariate analysis showed aortic regurgitation (23%) to be related to male sex (OR: 2.80, p<0.0001) and valve prolapse (OR: 5.16, p<0.0001), and aortic stenosis (22%) to BAV-RN (OR: 2.09, p<0.001), the presence of raphe (OR: 2.75, p<0.001), age (OR: 1.03; p<0.001), dyslipidaemia (OR: 1.77, p<0.01) and smoking (OR: 1.63, p<0.05). Ascending aorta was dilated in 76% without differences among morphotypes and associated with significant valvular dysfunction. By contrast, aortic root was dilated in 34% and related to male sex and aortic regurgitation but was less frequent in aortic stenosis and BAV-RN.

Conclusions

Normofunctional valves are more prevalent in BAV without raphe. Aortic stenosis is more frequent in BAV-RN and associated with some cardiovascular risk factors, whereas aortic regurgitation (AR) is associated with male sex and sigmoid prolapse. Although ascending aorta is the most commonly dilated segment, aortic root dilation is present in one-third of patients and associated with AR. Remarkably, BAV-RL increases the risk for dilation of the proximal aorta, whereas BAV-RN spares this area.

Evolution of Precision Medicine and Surgical Strategies for Bicuspid Aortic Valve-Associated Aortopathy

Bicuspid aortic valve (BAV) is a common congenital cardiac malformation affecting 1–2% of people. BAV results from fusion of two adjacent aortic valve cusps, and is associated with dilatation of the aorta, known as bicuspid valve associated aortopathy. Bicuspid valve aortopathy is progressive and associated with catastrophic clinical events, such as aortic dissection and rupture. Therefore, frequent monitoring and early intervention with prophylactic surgical resection of the proximal aorta is often recommended. However, the specific pattern of aortopathy is highly variable among patients, with different segments of the ascending aorta being affected. Individual patient risks are sometimes difficult to predict. Resection strategies are informed by current surgical guidelines which are primarily based on aortic size and growth criteria. These criteria may not optimally reflect the risk of important aortic events. To address these issues in the care of patients with bicuspid valve aortopathy, our translational research group has focused on validating use of novel imaging techniques to establish non-invasive hemodynamic biomarkers for risk-stratifying BAV patients. In this article, we review recent efforts, successes, and ongoing challenges in the development of more precise and individualized surgical approaches for patients with bicuspid aortic valves and associated aortic disease.

Aortic shear stress in patients with bicuspid aortic valve with stenosis and insufficiency

OBJECTIVES

Bicuspid aortic valve, characterized by valve malformation and risk for aortopathy, displays profound alteration in systolic aortic outflow and wall shear stress distribution. The present study performed 4-dimensional flow magnetic resonance imaging in patients with bicuspid aortic valve with right-left cusp fusion, focusing on the impact of valve function on hemodynamic status within the ascending aorta.

METHODS

Four-dimensional flow magnetic resonance imaging was performed in 50 subjects with right-left bicuspid aortic valve and 15 age- and aortic size-matched controls with tricuspid aortic valve. Patients with bicuspid aortic valve were categorized into 3 groups according to their aortic valve function as follows: bicuspid aortic valve with no more than mild aortic valve dysfunction (bicuspid aortic valve control, n = 20), bicuspid aortic valve with severe aortic insufficiency (n = 15), and bicuspid aortic valve with severe aortic stenosis (n = 15).

RESULTS

All patients with right-left bicuspid aortic valve exhibited peak wall shear stress at the right-anterior position of the ascending aorta (bicuspid aortic valve vs trileaflet aortic valve at the right-anterior position: 0.91 ± 0.23 N/m² vs 0.43 ± 0.12 N/m², P < .001) with no distinct alteration between bicuspid aortic valve with severe aortic insufficiency and bicuspid aortic valve with severe aortic stenosis. The predominance of dilatation involving the tubular ascending aorta (82%, type 2 aortopathy) persisted, with or without valve dysfunction. Compared with bicuspid aortic valve control subjects, the bicuspid aortic valve with severe aortic insufficiency group displayed universally elevated wall shear stress (0.75 ± 0.12 N/m² vs 0.57 ± 0.09 N/m², P < .01) in the ascending aorta, which was associated with elevated cardiac stroke volume (P < .05). The bicuspid aortic valve with severe aortic stenosis group showed elevated flow eccentricity in the form of significantly increased standard deviation of circumferential wall shear stress, which correlated with markedly increased peak aortic valve velocity (P < .01).

CONCLUSIONS

The location of peak aortic wall shear stress and type of aortopathy remained homogeneous among patients with right-left bicuspid aortic valve irrespective of valve dysfunction. Severe aortic insufficiency or stenosis resulted in further elevated aortic wall shear stress and exaggerated flow eccentricity.

Bicuspid Aortic Valve Morphotype Correlates With Regional Antioxidant Gene Expression Profiles in the Proximal Ascending Aorta

BACKGROUND

Bicuspid aortic valve (BAV) is associated with asymmetric dilatation of the proximal ascending aorta. We previously demonstrated increased susceptibility of smooth muscle cells to oxidative stress in the BAV-aneurysmal aorta and hypothesized that antioxidant expression is regionally defined and influenced by the BAV morphotype.

METHODS

BAV valve morphology was defined according to number of raphes: type 0 (0 raphes), type 1 (1 raphe), or type 2 (2 raphes) and by the raphe location among the left (L), right (R) or non (N) coronary cusps. Ascending aortic specimens were partitioned into three regions corresponding to the sinuses of Valsalva, denoted R, N (greater curve), and L (lesser curve). Transcripts 1, 2, and 3 from the gene expressing superoxide dismutase (Sod) were quantified in all three regions. Results were compared with aneurysmal and nonaneurysmal aortic specimens from patients with a tricuspid aortic valve.

RESULTS

Region-specific Sod1 upregulation and Sod2 downregulation were dependent on the BAV morphotype. Sod3 was uniformly downregulated in all regions in a morphotype-independent manner. Sod1 upregulation was noted in the R region of the nonaneurysmal type 1 L/R morphotype. Aortic valve regurgitation, but not stenosis, affected the expression of Sod isoforms in specimens of degenerative aneurysms.

CONCLUSIONS

Region-specific transcription profiles of Sod on the basis of BAV morphotype deepen our understanding of its associated aortopathy and provide biological insight on the asymmetric dilatation pattern. This work indicates regional differences exist in the oxidative stress biology of the proximal aortic wall, and this may lead to newer diagnostic techniques to adjudicate aortic catastrophe risk.

Year in review: bicuspid aortopathy

PURPOSE OF REVIEW

This article outlines the key research contribution to bicuspid aortic valve (BAV) aortopathy over the past 18 months.

RECENT FINDINGS

Investigators have further defined the current gaps in knowledge and the scope of the clinical problem of BAV aortopathy. Support for aggressive resection strategies is waning as evidence mounts to suggest that BAV is not similar to genetic connective tissue disorders with respect to aortic risks. The role of cusp fusion patterns and valve-mediated hemodynamics in disease progression is a major area of discovery. Molecular and cellular mechanisms remain elusive and contradictory.

SUMMARY

BAV aortopathy is a major public health problem that remains poorly understood. New insights on valve-mediated hemodynamics using novel imaging modalities may lead to more individualized resection strategies and improved clinical guidelines.