Aortic dimensions in patients with bicuspid aortic valve without significant valve dysfunction

Aortic events and relative survival in patients with moderately dilated proximal thoracic aorta

Objectives. This study describes growth, local and remote aortic events, and survival in patients with proximal (root, ascending) aortic diameters just below threshold for operation. Methods. Patients with proximal aortic diameter of 4.5 to 5.4 cm at baseline, were followed with serial computed tomography studies and data collected retrospectively. Aortic growth rate was estimated using mixed effects modelling. Clinical and radiological features associated with outcomes (all-cause death, aortic death, local or remote aortic events (dissection, rupture, intramural hematoma, or intervention)) were assessed with Cox analysis. Survival and freedom from events were estimated using Kaplan-Meier methods. Results. 80 patients underwent 274 CT scans during 265 patient-years. Median proximal aortic growth was 0.2 cm in 3 years. 32 events occurred in 28 patients (35%). Eleven events were local, all elective proximal aortic surgery. Nine events were remote: 5 type B aortic dissections, 3 descending aneurysms undergoing elective repair, and one infrarenal aortic rupture. Twelve patients died, half of type B aortic dissection. Relative survival compared to a matched normal population was 82% (95% confidence limits 55-98%) at 10 years. In Cox analysis, increased descending aortic diameter was an independent predictor of all-cause death (hazard ratio [HR], 1.39) and aortic death (HR 1.96). Conclusions. Descending, but not proximal, aortic growth was predictive of lethal events. The decreased relative survival, the substantial number of remote aortic events and aortic deaths strongly suggest continuous serial CT surveillance of the entire aorta. Other indicators than proximal aortic diameter appear needed to improve management of this patient group.

Identification of Genetic Variants Associated with Hereditary Thoracic Aortic Diseases (HTADs) Using Next Generation Sequencing (NGS) Technology and Genotype-Phenotype Correlations

Hereditary thoracic aorta diseases (HTADs) are a heterogeneous group of rare disorders whose major manifestation is represented by aneurysm and/or dissection frequently located at the level of the ascending thoracic aorta. The diseases have an insidious evolution and can be encountered as an isolated manifestation or can also be associated with systemic, extra-aortic manifestations (syndromic HTADs). Along with the development of molecular testing technologies, important progress has been made in deciphering the heterogeneous etiology of HTADs. The aim of this study is to identify the genetic variants associated with a group of patients who presented clinical signs suggestive of a syndromic form of HTAD. Genetic testing based on next-generation sequencing (NGS) technology was performed using a gene panel (Illumina TruSight Cardio Sequencing Panel) or whole exome sequencing (WES). In the majority of cases (8/10), de novo mutations in the FBN1 gene were detected and correlated with the Marfan syndrome phenotype. In another case, a known mutation in the TGFBR2 gene associated with Loeys-Dietz syndrome was detected. Two other pathogenic heterozygous variants (one de novo and the other a known mutation) in the SLC2A10 gene (compound heterozygous genotype) were identified in a patient diagnosed with arterial tortuosity syndrome (ATORS). We presented the genotype-phenotype correlations, especially related to the clinical evolution, highlighting the particularities of each patient in a family context. We also emphasized the importance of genetic testing and patient monitoring to avoid acute aortic events.

Assessing turbulent effects in ascending aorta in presence of bicuspid aortic valve

Aortic valves with bicuspids have two rather than three leaflets, which is a congenital heart condition. About 0.5-2% of people have a bicuspid aortic valve. Blood flow through the aorta is commonly believed to be laminar, although aortic valve disorders can cause turbulent transitions. Understanding the impact of turbulence is crucial for foreseeing how the disease will progress. The study's objective was use large eddy simulation to provide a thorough analysis of the turbulence in bicuspid aortic valve dysfunction. Using a large eddy simulation, the blood flow patterns of the bicuspid and tricuspid aortic valves were compared, and significant discrepancies were found. The velocity field in flow in bicuspid configurations was asymmetrically distributed toward the ascending aorta. In tricuspid aortic valve (TAV) the flow, on the other hand, was symmetrical within the same aortic segment. Moreover, we looked into standard deviation, Q-criterion, viscosity ratio and wall shear stresses for each cases to understand transition to turbulence. Our findings indicate that in the bicuspid aortic valve (BAV) case, the fluid-dynamic abnormalities increase. The global turbulent kinetic energy and time-averaged wall shear stress for the TAV and BAV scenarios were also examined. We discovered that the global turbulent kinetic energy was higher in the BAV case compared to TAV, in addition to the increased wall shear stress induced by the BAV in the ascending aorta.

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.

Tracking an Elusive Killer: State of the Art of Molecular-Genetic Knowledge and Laboratory Role in Diagnosis and Risk Stratification of Thoracic Aortic Aneurysm and Dissection

The main challenge in diagnosing and managing thoracic aortic aneurysm and dissection (TAA/D) is represented by the early detection of a disease that is both deadly and “elusive”, as it generally grows asymptomatically prior to rupture, leading to death in the majority of cases. Gender differences exist in aortic dissection in terms of incidence and treatment options. Efforts have been made to identify biomarkers that may help in early diagnosis and in detecting those patients at a higher risk of developing life-threatening complications. As soon as the hereditability of the TAA/D was demonstrated, several genetic factors were found to be associated with both the syndromic and non-syndromic forms of the disease, and they currently play a role in patient diagnosis/prognosis and management-guidance purposes. Likewise, circulating biomarker could represent a valuable resource in assisting the diagnosis, and several studies have attempted to identify specific molecules that may help with risk stratification outside the emergency department. Even if promising, those data lack specificity/sensitivity, and, in most cases, they need more testing before entering the “clinical arena”. This review summarizes the state of the art of the laboratory in TAA/D diagnostics, with particular reference to the current and future role of molecular-genetic testing.

Clinical Outcomes of Adults With Bicuspid Aortic Valve: A European Perspective

OBJECTIVE

To describe the clinical history of patients with a wide age range diagnosed with bicuspid aortic valve (BAV) and no surgical indication and to evaluate the long-term outcome of patients with BAV referred for elective surgery.

PATIENTS AND METHODS

Between 2005 and 2017, 350 consecutive patients with no surgical indication (surveillance group, mean age 53±16, 71% men) and 191 with a surgical indication (surgical group, mean age 59±13, 71% men) were prospectively included. Median follow-up was 80 (32 to 115) months.

RESULTS

In the surveillance group, the 5-year and 10-year survival rates were 93±1% and 89±2%, respectively, with a relative survival of patients with BAV compared with an age- and sex-matched control population of 98.7%. During follow-up, the cumulative 10-year incidence of aortic valve and aorta surgery was high; of 35±4%, the incidence of native valve infective endocarditis (IE) of 0.2% per patient-year, and no cases of aortic dissection were observed. In the surgical group, the 5-year and 10-year survival rates were 97±1% and 89±3%, respectively, with a relative survival of 99.4% compared with the general population. The incidence of IE was 0.4% per patient-year, and no cases of aortic dissection were observed.

CONCLUSION

This regional cohort shows that the 10-year survival rates of patients with BAV and a wide age range, but mostly middle-aged adults, were similar to those of the general population with a very low rate of complications. Adherence to prophylactic surgical indications and younger age might have contributed to this lack of difference.

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.

Aortopathy in Congenital Heart Disease

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

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

Background:

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

Methods:

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

Results:

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

Conclusions:

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

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.

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 bicuspid aortic valve: Is it an immunological disease process?

Bicuspid aortic valves (BAVs) are the most common congenital cardiac condition and are characterized by a structural abnormality whereby the aortic valve is composed of two leaflets instead of being trileaflet. It is linked to an increased risk for a variety of complications of the aorta, many with an immunological pathogenesis. The aim of this study is to review and analyze the literature regarding immunological processes involving BAVs, associated common pathologies, and their incidence in the population. This study will also examine current trends in surgical and therapeutic approaches to treatment and discuss the future direction of BAV treatment.

Association between aortic valvular calcification and characteristics of the aortic valve in patients with bicuspid aortic valve stenosis

BACKGROUND

Aortic valve calcification quantification using cardiac computed tomography (CCT) is a reliable marker for aortic stenosis (AS) in patients with bicuspid aortic valve (BAV) disease.

PURPOSE

To determine the association of Agatston aortic valve calcium score (AVCS) with morphological and hemodynamic characteristics of BAV and define cut-off AVCS for optimizing the grade of AS in patients with bicuspid AS.

MATERIAL AND METHODS

This study included 161 BAV patients with AS regardless of aortic regurgitation who underwent transthoracic echocardiography and CCT. BAVs were classified according to orientation of cusps and presence of raphe. Associations of AVCS with characteristics of BAV morphology and functional variables were determined by linear regression analysis. Area under the receiver operating characteristic curve (AUC) was used to determine the cut-off AVCS greater than which the diagnosis of severe AS was optimized.

RESULTS

AVCS was significantly different according to sex ( P < 0.001), AS severity ( P < 0.001), type of valvular dysfunction ( P = 0.011), and orientation of cusps ( P = 0.028). Multiple linear regression showed that AVCS was significantly associated with sex (estimate = -0.583, P < 0.001) and AS severity (estimate = 0.817, P < 0.001). AVCS was a predictor for severe AS with AUC of 0.80 in both women ( P = 0.002) and men ( P < 0.001). Its cut-off value was 1423 Agatston unit (AU) in women and 2573 AU in men.

CONCLUSIONS

In patients with bicuspid AS, AVCS was significantly higher in men and those with severe AS. However, AVCS was not significantly associated with morphological characteristics of BAV or the type of valvular dysfunction.

Aortic stiffness in aortic stenosis assessed by cardiovascular MRI: a comparison between bicuspid and tricuspid valves

Objectives

To compare aortic size and stiffness parameters on MRI between bicuspid aortic valve (BAV) and tricuspid aortic valve (TAV) patients with aortic stenosis (AS).

Methods

MRI was performed in 174 patients with asymptomatic moderate-severe AS (mean AVAI 0.57 ± 0.14 cm²/m²) and 23 controls on 3T scanners. Valve morphology was available/analysable in 169 patients: 63 BAV (41 type-I, 22 type-II) and 106 TAV. Aortic cross-sectional areas were measured at the level of the pulmonary artery bifurcation. The ascending and descending aorta (AA, DA) distensibility, and pulse wave velocity (PWV) around the aortic arch were calculated.

Results

The AA and DA areas were lower in the controls, with no difference in DA distensibility or PWV, but slightly lower AA distensibility than in the patient group. With increasing age, there was a decrease in distensibility and an increase in PWV. After correcting for age, the AA maximum cross-sectional area was higher in bicuspid vs. tricuspid patients (12.97 [11.10, 15.59] vs. 10.06 [8.57, 12.04] cm², p < 0.001), but there were no significant differences in AA distensibility (p = 0.099), DA distensibility (p = 0.498) or PWV (p = 0.235). Patients with BAV type-II valves demonstrated a significantly higher AA distensibility and lower PWV compared to type-I, despite a trend towards higher AA area.

Conclusions

In patients with significant AS, BAV patients do not have increased aortic stiffness compared to those with TAV despite increased ascending aortic dimensions. Those with type-II BAV have less aortic stiffness despite greater dimensions. These results demonstrate a dissociation between aortic dilatation and stiffness and suggest that altered flow patterns may play a role.

Key Points

• Both cellular abnormalities secondary to genetic differences and abnormal flow patterns have been implicated in the pathophysiology of aortic dilatation and increased vascular complications associated with bicuspid aortic valves (BAV).

• We demonstrate an increased ascending aortic size in patients with BAV and moderate to severe AS compared to TAV and controls, but no difference in aortic stiffness parameters, therefore suggesting a dissociation between dilatation and stiffness.

• Sub-group analysis showed greater aortic size but lower stiffness parameters in those with BAV type-II AS compared to BAV type-I.

Electronic supplementary material

The online version of this article (10.1007/s00330-018-5775-6) contains supplementary material, which is available to authorized users.

Aortic elasticity and the influence of valve morphology in children with bicuspid aortic valve

AimWe investigated dimensions and elasticity of whole aorta in patients with bicuspid aortic valve and influence of valve phenotype.

METHOD

The study group included 44 patients and 42 controls. Patients were divided into groups according to the type of valve opening as horizontal - fusion between right and left coronary cusps - and vertical - fusion between right-non-coronary cusps; according to age they were divided into younger (5-10 years) and older patients (11-16 years). Our study did not include valve phenotype with fusion between left and non-coronary cusps. Systolic-diastolic diameters of aortic annulus, sinus valsalva, sinutubular junction, arcus, and ascending-descending and abdominal aorta were measured and z-scores were obtained. Aortic strain, distensibility, and stiffness index were calculated. Flow-mediated dilatation of brachial artery was studied.

RESULTS

z-Scores at annulus, sinus valsalva, sinutubular junction, and ascending aorta were higher in study patients (p=0.001, p=0.0001, p=0.0001, p=0.0001, respectively). z-Scores of sinus valsalva and sinotubular junction were higher in the horizontal group than in the vertical group (p=0.006, p=0.023, respectively). z-Score was over +2 in 51% of patients with horizontal morphology and 33% of patients with vertical morphology (p=0.0001). Ascending aorta was more distensible and less stiff in the study group (11.3±5.63 versus 7.91±4.5, p=0.002; 4.76±3.60 versus 6.19±3.44 cm2.dyn-1.10-6, p=0.033, respectively). Stiffness index of ascending, arcus, and abdominal aorta were higher in the horizontal group (p=0.004, p=0.038, p=0.006, respectively). Ascending aorta was more distensible and less stiff in the younger group (p=0.007, p=0.027, respectively) but did not differ in the older group compared with the control group.

CONCLUSION

Aortic dimensions are enlarged in patients with bicuspid aortic valve starting from childhood, suggesting the presence of generalised aortopathy. Aortic elasticity is increased at young age and decreased with age.

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.

Defective NOTCH signaling drives increased vascular smooth muscle cell apoptosis and contractile differentiation in bicuspid aortic valve aortopathy: A review of the evidence and future directions

Bicuspid aortic valve (BAV) disease remains the most common congenital cardiac disease and is associated with an increased risk of potentially fatal aortopathy including aortic aneurysm and dissection. Mutations in the NOTCH1 gene are one of only a few genetic anomalies identified in BAV disease; however evidence for defective NOTCH signaling, and its involvement in the characteristic histological changes of VSMC apoptosis and differentiation in ascending aortae of BAV patients is lacking. This review scrutinizes the evidence for the interactions of NOTCH signaling, cellular differentiation and apoptosis in the context of aortic VSMCs and provides focus for future research efforts in the diagnosis of BAV aortopathy and prevention of catastrophic complications through NOTCH signaling manipulation.

Characteristics of aorto-iliofemoral arterial tree according to aortic valve morphology in chinese patients considered for TAVR

To characterize the anatomy of aorto-iliofemoral arterial tree according to aortic valve phenotype by CT in patients referred for transcatheter aortic valve replacement (TAVR). We retrospectively enrolled 215 patients screened for TAVR who underwent CT. Dimensions, calcification, vascular tortuosity index score and other putative risk features of 13 different regions were evaluated for bicuspid aortic valve (BAV) and tricuspid aortic valve (TAV) morphology. The study consisted of 44% BAVs with younger age than TAVs. The dimensions of the annulus, sinus of Valsalva, ascending aorta and aortic arch were consistently larger in BAVs. The prevalence of calcification of aortic arch was significantly higher in TAVs even after adjustment for atherosclerotic risk factors. BAVs was associated with two-fold higher odds of having over I degree AA calcification (odds ratio 2.02; 95% CI 1.60-5.31; p < 0.001). The prevalence of severe iliac tortuosity was higher among BAVs (11.7 vs. 2.5%, p = 0.015). BAVs had a trend to more atheroma than TAVs in the abdominal aortic artery and iliofemoral artery. BAV anatomy is common in Chinese AS patients screened for TAVR. Aorto-iliofemoral pathology varies according to aortic valve phenotype, which may contribute to technical challenges in BAV vs. TAV anatomy and support the need for the integrated risk assessment for each valve phenotype.

Bicuspid aortic valve morphology and its impact on aortic diameters-A systematic review with meta-analysis and meta-regression

AIM

To evaluate the impact of the 2 most common bicuspid aortic valve (BAV) morphology patterns [right-left (RL) vs right-noncoronary (RN) cusp fusion] on the aortic diameters and the impact of gender, aortic stenosis (AS), aortic regurgitation (AR), and age on the observed effects.

METHODS

The PubMed databases was searched up to December 31, 2016 to identify studies investigating the morphology of BAV and aortic diameters. Inclusion criteria were as follows: the data on diameter of sinuses of Valsalva (SVD) and/or ascending aorta (AAD) and BAV morphology. The additional characteristics [gender, AS and AR (% of patients with moderate or severe AS/AR) and mean age] were collected to perform a meta-regression analysis.

RESULTS

A total of 12 studies with 2192 patients with indexed AAD, 15 studies with 3104 patients with nonindexed AAD and 8 studies with 1271 patients with indexed SVD, and 16 studies with 3454 patients with nonindexed SVD were included. There was no difference between RL and RN group in indexed/nonindexed AAD-mean difference (MD): 0.06 mm/m² (95% CI: -0.65 to 0.77 mm/m² , P = .87) and -0.06 mm (95% CI: 1.10-0.97 mm, P = .91). Differently, the RL BAV was associated with larger indexed/nonindexed SVD than RN phenotype-MD: 1.66 mm/m² (95% CI: 0.83-2.49 mm/m² , P < .001) and 2.03 mm (95% CI: 0.97-3.09 mm, P < .001). Age, gender, AS, and AR had no influence on observed differences.

CONCLUSIONS

RL BAV phenotype is associated with larger SVD than RN BAV, and the observed differences are independent from aortic valve dysfunction degree, age, and gender.

Aortic Dilatation Associated With Bicuspid Aortic Valve: Relation to Sex, Hemodynamics, and Valve Morphology (the National Heart Lung and Blood Institute-Sponsored National Registry of Genetically Triggered Thoracic Aortic Aneurysms and Cardiovascular Conditions)

This study analyzed the impact of sex, hemodynamic profile, and valve fusion pattern on aortopathy associated with bicuspid aortic valve (BAV). The National Heart Lung and Blood Institute-sponsored National Registry of Genetically Triggered Thoracic Aortic Aneurysms and Cardiovascular Conditions (GenTAC) provided comprehensive information on a large population of well-characterized patients with BAV. Of 969 enrolled patients with BAV, 551 (57%, 77% male) had already undergone valvular and/or aortic surgery. Echocardiographic imaging data were available on 339 unoperated or preoperative participants who formed the basis of this study. BAV function was normal in 45 (14%), with a predominant aortic regurgitation (AR) in 127 (41%) and a predominant aortic stenosis (AS) in 76 (22%). Moderate-severe AR was associated with larger sinus of Valsalva (SOV) diameters compared with normal function and AS (all p <0.01). Moderate-severe AS was associated with a larger ascending aortic (AscAo) diameter compared with normal function (p = 0.003) but not with AR. The SOV diameter was larger in men than in women (3.7 ± 0.7 vs 3.3 ± 0.6 cm, p <0.0001), whereas AscAo diameters were comparable (3.9 ± 0.9 vs 3.7 ± 0.9 cm, p = 0.08). Right-left commissural fusion was associated with a larger SOV diameter (3.7 ± 0.7 vs 3.3 ± 0.6 cm, p <0.0001) compared with a right-noncoronary fusion pattern. Predominant AR was more common in men (45% vs 27%, p = 0.004), whereas AS was more common in women (29% vs 18%, p = 0.04). In conclusion, in the GenTAC Registry, AR was associated with diffuse (annular, SOV, and AscAo) enlargement, whereas moderate-severe AS was only associated with AscAo enlargement. Male sex and right-left cusp pattern of cusp fusion were associated with larger SOV diameters and a greater likelihood of AR, whereas women had a higher prevalence of AS.

Evidence of subannular and left ventricular morphological differences in patients with bicuspid versus tricuspid aortic valve stenosis: magnetic resonance imaging-based analysis

Objectives

Prospective analysis of left ventricular (LV) morphological/functional parameters in patients with bicuspid versus tricuspid aortic valve (TAV) stenosis undergoing aortic valve replacement (AVR) surgery.

Methods

A total of 190 consecutive patients with BAV ( n  = 154) and TAV stenosis ( n  = 36) (mean age 61 ± 8 years, 65% male) underwent AVR ± concomitant aortic surgery from January 2012 through May 2015. All patients underwent preoperative cardiac magnetic resonance imaging in order to evaluate: (i) left ventricular outflow tract (LVOT) dimensions, (ii) length of anterior mitral leaflet (AML), (iii) end-systolic and end-diastolic LV wall thickness, (iv) LV area, (v) LV end-systolic and end-diastolic diameters (LVESD, LVEDD), (vi) LV end-diastolic and end-systolic volumes (LVEDV, LVESV) and (vii) maximal diameter of aortic root. These parameters were compared between the two study groups.

Results

The LVOT diameter was significantly larger in BAV patients (21.7 ± 3 mm in BAV vs 18.9 ± 3 mm in TAV, P  < 0.001). Moreover, BAV patients had significantly longer AML (24 ± 3 mm in BAV vs 22 ± 4 mm in TAV, P  = 0.009). LVEDV and LVESV were significantly larger in BAV patients (LVEDV: 164.9 ± 68.4 ml in BAV groups vs 126.5 ± 53.1 ml in TAV group, P  = 0.037; LVESV: 82.1 ± 57.9 ml in BAV group vs 52.9 ± 25.7 ml in TAV group, P  = 0.008). A strong linear correlation was found between LVOT diameter and aortic annulus diameter in BAV patients ( r  = 0.7, P  < 0.001), whereas significantly weaker correlation was observed in TAV patients ( r  = 0.5, P  = 0.006, z  = 1.65, P  = 0.04). Presence of BAV morphology was independently associated with larger LVOT diameters (OR 9.0, 95% CI 1.0-81.3, P  = 0.04).

Conclusions

We found relevant differences in LV morphological/functional parameters between BAV and TAV stenosis patients. Further investigations are warranted in order to determine the cause of these observed differences.

Higher neutrophil to lymphocyte ratio is related to a lower ejectionfraction in bicuspid aortic valve patients

BACKGROUND/AIM

Inflammation plays an important role in the pathophysiology of vascular disease. In this study, we aimed to evaluate the associations of neutrophil to lymphocyte ratio (NLR; an indicator of inflammation) with left ventricular ejection fraction and ascending aorta diameter in patients with a bicuspid aortic valve (BAV).

MATERIALS AND METHODS

One hundred and thirty-nine consecutive patients with the diagnosis of BAV were enrolled in the study. Complete blood counts were analyzed for neutrophil and lymphocyte levels and NLR. The subjects were separated into two groups based on their ascending aorta diameter. The patients with ascending aorta diameter equal to or above 3.9 cm were included in group 1 whereas those with ascending aorta diameter below 3.9 cm were included in group 2.

RESULTS

When the results were compared, it was demonstrated that there was a positive correlation between NLR and ascending aorta diameter (r: 0.485, P = 0.026), whereas there was a negative correlation between NLR and left ventricular end-diastolic diameter (r: 0.475, P = 0.030), left ventricular end-systolic diameter (r: 0.482, P = 0.027), and left ventricular ejection fraction (r: -0.467, P = 0.033) in BAV patients with ascending aorta dilatation (group 1).

CONCLUSION

NLR is associated with ascending aorta diameter and left ventricular ejection fraction in BAV patients with ascending aorta dilatation.

Outcomes After Operations for Unicuspid Aortic Valve With or Without Ascending Repair in Adults

BACKGROUND

Unicuspid aortic valve is an important subset of bicuspid aortic valve, and knowledge regarding its aortopathy pattern and surgical outcomes is limited. Our objectives were to characterize unicuspid aortic valve patients, associated aortopathy, and surgical outcomes.

METHODS

From January 1990 to May 2013, 149 adult unicuspid aortic valve patients underwent aortic valve replacement or repair for aortic stenosis (n = 13), regurgitation (n = 13), or both (n = 123), and in 91 (61%) the aortic valve operation was combined with aortic repair. Data were obtained from the Cardiovascular Information Registry and medical record review. Three-dimensional imaging analysis was performed from preoperative computed tomography and magnetic resonance imaging scans. The Kaplan-Meier method was used for survival analysis.

RESULTS

Patients had a mean maximum aortic diameter of 44 ± 8 mm and variably involved the aortic root, ascending, or arch, or both. Patients with valve operations alone were more likely to be hypertensive (p = 0.01) and to have severe aortic stenosis (p = 0.07) than those who underwent concurrent aortic operations. There were no operative deaths, strokes, or myocardial infarctions. Patients undergoing aortic repair had better long-term survival. Estimated survival at 1, 5, and 10 years was 100%, 100%, and 100% after combined operations and was 100%, 88%, and 88% after valve operations alone (p = 0.01).

CONCLUSIONS

Patients with a dysfunctional unicuspid aortic valve frequently present with an ascending aneurysm that requires repair. Combined aortic valve operations and aortic repair was associated with significantly better long-term survival than a valve operation alone. Further study of this association may direct decisions about timing of surgical intervention.

Evidence of Aortopathy in Mice with Haploinsufficiency of Notch1 in Nos3-Null Background

Thoracic aortic aneurysms (TAA) are a significant cause of morbidity and mortality in humans. While the exact etiology is unknown, genetic factors play an important role. Mutations in NOTCH1 have been linked to bicuspid aortic valve (BAV) and aortopathy in humans. The aim of this study was to determine if haploinsufficiency of Notch1 contributes to aortopathy using Notch1^+/−; Nos3^−/− mice. Echocardiographic analysis of Notch1^+/−; Nos3^−/− mice reveals effacement of the sinotubular junction and a trend toward dilation of the aortic sinus. Furthermore, examination of the proximal aorta of Notch1^+/−; Nos3^−/− mice reveals elastic fiber degradation, a trend toward increased matrix metalloproteinase 2 expression, and increased smooth muscle cell apoptosis, features characteristic of aneurysmal disease. Although at a lower penetrance, we also found features consistent with aortopathic changes in Notch1 heterozygote mice and in Nos3-null mice. Our findings implicate a novel role for Notch1 in aortopathy of the proximal aorta.

The Role of Multimodality Cardiac Imaging for the Assessment of Sports Eligibility in Patients with Bicuspid Aortic Valve

Bicuspid aortic valve (BAV) cannot be considered an innocent finding, but it is not necessarily a life-threatening condition. Athletes with BAV should undergo a thorough staging of the valve anatomy, taking into consideration hemodynamic factors, as well as aortic diameters and looking for other associated significant cardiovascular anomalies by use of a multimodality cardiac imaging approach. Furthermore an accurate follow-up is mandatory with serial cardiological controls in those allowed to continue sports.

A fatal outcome of thoracic aortic aneurysm in a male patient with bicuspid aortic valve

Thoracic aortic aneurysm is often an asymptomatic but potentially lethal disease if its most catastrophic complication – aortic dissection – occurs. Thoracic aortic dissection is associated with a high mortality rate despite ongoing improvement in its management. We report a fatal outcome of thoracic aortic aneurysm in a male patient with bicuspid aortic valve. The patient was qualified for elective surgery of the ascending aorta and aortic valve at the age of 39 but he did not agree to undergo the proposed procedure. Three years later, he experienced acute aortic dissection and died despite a prompt diagnosis and complex management.

Association between leaflet fusion pattern and thoracic aorta morphology in patients with bicuspid aortic valve

PURPOSE

To determine if patients with certain bicuspid aortic valve (BAV) phenotypes are predisposed to particular morphological abnormalities of the thoracic aorta.

MATERIALS AND METHODS

One hundred ninety-two patients with BAV who underwent magnetic resonance angiography between January 2007 and July 2010 were retrospectively identified. Aortic morphology was examined through measurements of aortic size index at nine levels along the thoracic aorta, three-dimensional volume of the ascending aorta, vessel asymmetry, and assessment of aortic root morphology.

RESULTS

We found 140 patients (73%) with right and left coronary cusps (R-L) fusion, 46 patients (24%) with R-N fusion, and 6 patients (3%) with left and noncoronary cusps (L-N) fusion. Mean aortic volume in the proximal ascending aorta was significantly greater in R-L patients (0.93 versus 0.60 cm(3)/m(2); P < 0.01). R-N patients possessed greater aortic size index at the distal ascending aorta and proximal aortic arch, and were also significantly more likely to have Type 2 patterns of aortic dilatation.

CONCLUSION

Our results suggest that BAV with R-L fusion is associated with increased dimensions of the aortic root, while BAV with R-N fusion is associated with increased dimensions of the distal ascending aorta and proximal arch. Our findings illustrate the morphological heterogeneity that exists among BAV phenotypes.

Association between bicuspid aortic valve phenotype and patterns of valvular dysfunction and bicuspid aortopathy: comprehensive evaluation using MDCT and echocardiography

OBJECTIVES

We sought to define the clinical importance of an integrated classification of bicuspid aortic valve (BAV) phenotypes and aortopathy using multidetector computed tomography (MDCT).

BACKGROUND

An association between BAV phenotypes and the pattern of valvular dysfunction or bicuspid aortopathy has yet to be definitely established.

METHODS

The study cohort included 167 subjects (116 men, age 54.6 ± 14.4 years) who underwent both MDCT and transthoracic echocardiography from 2003 to 2010. Two BAV phenotypes-fusion of the right and left coronary cusps (BAV-AP) and fusion of the right or left coronary cusp and noncoronary cusp (BAV-RL)-were identified. Forty-five patients showed normal aortic dimensions and were classified as type 0. In the remaining patients, hierarchic cluster analysis showed 3 different types of bicuspid aortopathy according to the pattern of aortic dilation: type 1 (aortic enlargement confined to the sinus of Valsalva [n = 34]), type 2 (aortic enlargement involving the tubular portion of the ascending aorta [n = 49]), and type 3 (aortic enlargement extending to the transverse aortic arch [n = 39]).

RESULTS

The prevalence of BAV-AP and BAV-RL was 55.7% and 44.3%, respectively. Comparing BAV-AP and BAV-RL, no differences in age or in the prevalence of male sex were determined. However, significant differences in the valvular dysfunction pattern were noted, with moderate-to-severe aortic stenosis predominating in patients with BAV-RL (66.2% vs. 46.2% in BAV-AP; p = 0.01), and moderate-to-severe aortic regurgitation in BAV-AP (32.3% vs. 6.8% in BAV-RL; p < 0.0001). A normal aorta was the most common phenotype in BAV-AP patients (33.3% vs. 18.9% in BAV-RL; p = 0.037), and type 3 aortopathy was the most common phenotype in BAV-RL patients (40.5% vs. 9.7% in BAV-AP; p < 0.0001).

CONCLUSIONS

The patterns of valvular dysfunction and bicuspid aortopathy differed significantly between the 2 BAV phenotypes, suggesting the possibility of etiologically different entities.

Hereditary patterns of bicuspid aortic valve in a hundred families

BACKGROUND

To study the following characteristics of bicuspid aortic valves (BAVs): 1) the recurrence rate in our population, 2) patterns of hereditary transmission in different BAV morphologies and 3) the aortic dimensions of BAVs in first-degree relatives (FDRs).

METHODS

A cross-sectional, prospective study of 100 consecutive families of BAV patients attending a university hospital. The following aortic valve morphologies were analysed and categorised: fusion of the right and left coronary cusps (BAV type A), right and noncoronary cusps (type B) and of the left and noncoronary cusps (type C).

RESULTS

There were 553 subjects studied, 100 cases with a BAV (46.8±15 years, 66% male, type 67% A, 32% B and 1% C; 42% with aortic dilatation), 348 FDRs (44.8% male), and 105 healthy control subjects (50% male). We detected 16 BAVs among 348 FDRs. The recurrence rates were 15% for families, 4.6% for FDRs, 7.05% in men and 2.60% in women. The morphologic concordance in family members was 68.8%. The aortic dimensions in 270 adult FDRs with a tricuspid aortic valve were significantly smaller compared with BAV patients (sinus index diameter 1.60±0.19 cm/m(2) vs. 1.82±0.29 cm/m(2), p<0.001; tubular index diameter 1.51±0.23 cm/m(2) vs. 2.00±0.45 cm/m(2), p<0.001) and similar to 103 control subjects(sinus index diameter 1.60±0.19 cm/m(2) vs. 1.59±0.17 cm/m(2), p=0.600 and tubular index diameter 1.51±0.23 cm/m(2) vs. 1.53±0.18 cm/m(2), p=0.519).

CONCLUSIONS

In our population, the BAV recurrence rate in FDRs was low (4.6%). The hereditary transmission of morphologic BAV types seems by chance, and the aortic dimensions in tricuspid FDRs are normal.

Patterns of aortic dilatation in bicuspid aortic valve-associated aortopathy

BACKGROUND

Bicuspid aortic valves (BAVs) are associated with aortopathy. Recent studies suggest that aortic dilatation is more likely to be seen with left-right coronary cusp fusion (type I) compared with right-noncoronary cusp fusion (type II). The aim of this study was to investigate the association between BAV morphology and patterns of aortopathy.

METHODS

Aortic dimensions and BAV morphology were obtained retrospectively from archived cine loops of 581 consecutive patients with BAVs and 277 matched normal controls from the Vancouver General Hospital echocardiography database. Patient demographics and other echocardiographic parameters were extracted from the database.

RESULTS

The study population was composed of 71% type I BAVs (415 patients) and 26% type II BAVs (149 patients). Aortic dilatation was present in 30% of the population. Type I BAV was associated with increased dimensions indexed to body surface area at the sinus of Valsalva compared with type II BAV. No difference in proximal ascending aortic dimension was seen between different BAV morphologies. The pattern of dilatation with type I BAV was more likely to be at the level of the annulus or sinus of Valsalva compared with type II BAV (62% vs 33%, P= .002). Type I BAV was an independent predictor of proximal aortic dilatation (odds ratio, 3.42; 95% confidence interval, 1.07-10.9).

CONCLUSIONS

Type I BAV is associated with a greater likelihood of dilatation at the annulus and sinus of Valsalva. There is relative sparing of this region of the aorta in patients with type II BAVs. Individuals with different BAV morphologies may require different strategies of aortopathy surveillance.

Bicuspid aortic valve: inter-racial difference in frequency and aortic dimensions

OBJECTIVES

The objective of this study was to examine the similarities and differences in Caucasian (C) and African-American (AA) patients with bicuspid aortic valve (BAV) with respect to morphology, severity of aortic stenosis/insufficiency, and aortic dilation.

BACKGROUND

BAV is a common congenital valve abnormality, accounting for a large number of valve replacements.

METHODS

A total of 229 patients with the diagnostic code BAV were identified retrospectively from our computerized adult echocardiographic database, which consists of 91,896 studies performed at the University of Chicago Medical Center from 1998 to 2009, representing 40,878 patients. Of those, 183 patients with BAV were included in this retrospective BAV single-center cohort study and reanalyzed with a comprehensive assessment of aortic dimensions, aortic valve morphology and function, clinical cardiovascular risk factors, and patient characteristics.

RESULTS

Of the 183 patients with BAV, 138 were C and 45 were AA. Our echocardiographic database encompasses approximately 65% AA, 31% C, and 4% other races, for an estimated frequency of BAV in AA patients of 0.17% and a frequency in C patients of 1.1% (p = 0.001). There were no significant inter-racial differences regarding sex, height, weight, hyperlipidemia, diabetes, tobacco use, cardiac medications, and left ventricular ejection fraction. The AA cohort was older (age 50 ± 17 years vs. 43 ± 17 years, p < 0.05) and had a higher prevalence of hypertension (51% vs. 24%, p < 0.05). After adjusting for comorbidities, aortic dimensions were larger in C (C vs. AA: annulus, 2.4 ± 0.4 vs. 2.1 ± 0.4 cm; sinuses of Valsalva, 3.4 ± 0.7 vs. 3.1 ± 0.6 cm; sinotubular junction, 3.0 ± 0.6 vs. 2.6 ± 0.5 cm; and ascending aorta, 3.5 ± 0.7 vs. 3.2 ± 0.5 cm; all p values <0.05).

CONCLUSIONS

This is the first study to report racial differences among patients with BAV with reduced aortic dimensions in AA patients despite the presence of more risk factors, suggestive of marked heterogeneity in the BAV population and indicating race as a potential disease modifier in BAV.

Quantitative assessment of asymmetric aortic dilation with valve-related aortic disease

RATIONALE AND OBJECTIVES

Previous work suggests that ascending aortic (AsAo) dilation can be asymmetric and is potentially related to valve-related blood flow abnormalities. The aim of this study was to investigate the relationship between the aortic valve and AsAo dilation using a quantitative, three-dimensional assessment of aortic shapes.

MATERIALS AND METHODS

Computed tomographic and magnetic resonance images of the thorax were retrospectively reviewed. Four groups with aortic dilation were studied: those with tricuspid aortic valves (TAVs) with and without stenosis and those with bicuspid aortic valves (BAVs) with and without stenosis. Controls had either TAVs or BAVs but no aortic stenosis or dilation. In additional to standard orthogonal diameters, a unique measurement of AsAo asymmetry was used: the ratio of the greater to lesser curvatures measured using three-dimensional reformats in a "candy-cane" orientation.

RESULTS

A total of 105 patients were identified. Ratios of greater to lesser curvature in patients with aortic dilation and nonstenotic TAVs were not significantly different from those in controls (1.69 vs 1.55, P > .20), but the asymmetry reflected by this ratio was markedly increased in patients with aortic dilation and stenotic TAVs (1.94, P < .001). Patients with aortic dilation and BAVs had significantly elevated ratios regardless of the status of the aortic valve (1.96 for nonstenotic and 2.05 for stenotic vs 1.53 for controls, P < .001).

CONCLUSIONS

Asymmetric AsAo dilation with relative bulging of the greater curvature is linked to aortic stenosis, but it is also seen with nonstenotic BAVs. This suggests that the hemodynamic forces that contribute to aortic dilation are not fully revealed by conventional assessment of the aortic valve.

Patient-specific bicuspid valve dynamics: overview of methods and challenges

About 1-2 % of the babies are born with bicuspid aortic valves instead of the normal aortic valve with three leaflets. A significant portion of the patients with the congenital bicuspid valve morphology suffer from aortic valve stenosis and/or ascending aortic dilatation and dissection thus requiring surgical intervention when they are young adults. Patients with bicuspid aortic valves (BAVs) have also been found to develop valvular stenosis earlier than those with the normal aortic valve. This paper overviews current knowledge of BAVs, where several studies have suggested that the mechanical stresses induced on the valve leaflets and the abnormal flow development in the ascending aorta may be an important factor in the diseases of the valve and the aortic root. The long-term goals of the studies being performed in our laboratory are aimed towards potential stratification of bicuspid valve patients who may be at risk for developing these pathologies based on analyzing the hemodynamic environment of these valves using fluid-structure interaction (FSI) modeling. Patient-specific geometry of the normal tri-cuspid and bicuspid valves are reconstructed from real-time 3D ultrasound images and the dynamic analyses performed in order to determine the potential effects of mechanical stresses on the valve leaflet and aortic root pathology. This paper describes the details of the computational tools and discusses challenges with patient-specific modeling.

Current indications for surgical repair in patients with bicuspid aortic valve and ascending aortic ectasia

Preventive surgical repair of the moderately dilated ascending aorta/aortic root in patients with bicuspid aortic valve (BAV) is controversial. Most international reference centers are currently proposing a proactive approach for BAV patients with a maximum ascending aortic/root diameter of 45 mm since the risk of dissection/rupture raises significantly with an aneurysm diameter >50 mm. Current guidelines of the European Society of Cardiology (ESC) and the joint guidelines of the American College of Cardiology (ACC)/American Heart Association (AHA) recommend elective repair in symptomatic patients with dysfunctional BAV (aortic diameter ≥45 mm). In asymptomatic patients with a well-functioning BAV, elective repair is recommended for diameters ≥50 mm, or if the aneurysm is rapidly progressing (rate of 5 mm/year), or in case of a strong family history of dissection/rupture/sudden death, or with planned pregnancy. As diameter is likely not the most reliable predictor of rupture and dissection and the majority of BAV patients may never experience an aortic catastrophe at small diameters, an overly aggressive approach almost certainly will put some patients with BAV unnecessarily at risk of operative and early mortality. This paper discusses the indications for preventive, elective repair of the aortic root, and ascending aorta in patients with a BAV and a moderately dilated—or ectatic—ascending aorta.

Bicuspid aortic valve disease: a comprehensive review

Bicuspid aortic valve is the commonest congenital cardiac abnormality in the general population. This paper article will discuss our current knowledge of the anatomy, pathophysiology, genetics, and clinical aspects of bicuspid aortic valve disease.

Cardiac magnetic resonance imaging is more diagnostic than 2-dimensional echocardiography in determining the presence of bicuspid aortic valve

OBJECTIVE

This study compares 2-dimensional, transthoracic echocardiography with cardiac magnetic resonance imaging in the preoperative identification of bicuspid aortic valve before aortic valve surgery.

METHODS

Of 1203 patients who underwent an aortic valve operation, 218 had both preoperative transthoracic echocardiography and cardiac magnetic resonance imaging. Patients in the study group were aged 56 years and had an ejection fraction of 56%, 76% were male, and 29% had associated coronary artery disease. The results of transthoracic echocardiography and cardiac magnetic resonance imaging were classified as bicuspid aortic valve, trileaflet aortic valve, or nondiagnostic. Of the 218 patients, 123 (56%) had bicuspid aortic valve as determined at the time of surgery and 116 (53%) had an ascending aortic aneurysm.

RESULTS

Of the 123 patients with bicuspid aortic valve confirmed at surgery, by transthoracic echocardiography 76 (62%) were identified preoperatively with bicuspid aortic valve, 12 (10%) were misidentified with trileaflet aortic valve, and 35 (28%) were nondiagnostic for valve morphology. In the same patients with bicuspid aortic valve, by cardiac magnetic resonance imaging 115 (93%) were identified with bicuspid aortic valve, 5 (4%) were misidentified with trileaflet aortic valve, and 3 (2%) were nondiagnostic. The difference between transthoracic echocardiography and cardiac magnetic resonance imaging to determine the presence of bicuspid aortic valve was statistically significant (P<.001). In the entire cohort of patients, transthoracic echocardiography was diagnostic for valve morphology in 155 patients (71%) compared with cardiac magnetic resonance imaging, which was diagnostic in 212 patients (97%) (P<.001).

CONCLUSIONS

Cardiac magnetic resonance imaging is more diagnostic than transthoracic echocardiography in determining the presence of bicuspid aortic valve. A significant factor is the rate of nondiagnostic transthoracic echocardiography for aortic valve morphology. Cardiac magnetic resonance imaging can be performed as a complementary test when transthoracic echocardiography is nondiagnostic for aortic valve morphology.

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.

Influence of bicuspid valve geometry on ascending aortic fluid dynamics: a parametric study

Bicuspid aortic valve (BAV) predisposes to aortic aneurysms with a high prevalence. A first hypothesis for this phenomenon is related to fibrillin deficiency (genetic hypothesis). The present article focused on a complementary, hemodynamic hypothesis stating that it is the peculiar fluid dynamics of blood in the ascending aorta of patients with BAV configurations that leads to aneurysm formation. To corroborate this hypothesis, a parametric study was performed based on numerical simulations of ascending aorta hemodynamics with different configurations of orifice area and valve orientation. The resulting wall shear stress (WSS) distributions and degree of asymmetry of the blood jet were investigated, and surrogate indices introduced. The results showed that WSS was more pronounced in subjects with BAV morphologies, also in the nonstenotic case. In particular, a maximum WSS of 3Pa was found (vs. 1.5Pa in subjects with a tricuspid configuration). It is localized at the mid-ascending aorta, the segment more prone to dilate as shown by the index related to maximum WSS (0.869 in BAV vs. 0.322 in tricuspid). Moreover, the asymmetry of the blood flow was found larger for decreasing valve area, the related index at mid-ascending aorta being more than three times higher than that found for tricuspid configuration (0.70 vs. 0.20). Further, WSS and flow asymmetry were higher also at the sinus of Valsalva and sinotubolar junction for a latero-lateral (LL) BAV configuration in keeping with the clinical observation on association between BAV configurations and different aortic aneurysm morphology. These findings may help explain the higher risk of aneurysm formation in BAV patients. The proposed indices will require validation prior to application in clinical settings.

Aorta Measurements are Heritable and Influenced by Bicuspid Aortic Valve

Objectives: To determine whether the contributions of genetics and bicuspid aortic valve (BAV) independently influence aortic (Ao) dimensions. Background: Ao dilation is a risk factor for aneurysm, dissection, and sudden cardiac death. Frequent association of BAV with Ao dilation implicates a common underlying defect possibly due to genetic factors. Methods: Families enriched for BAV underwent standardized transthoracic echocardiography. In addition to BAV status, echocardiographic measures of Ao (annulus to descending Ao), pulmonary artery, and mitral valve annulus (MVA) diameters were obtained. Using variance components analysis, heritability was estimated with and without BAV status. Additionally, bivariate genetic analyses between Ao dimensions and BAV were performed. Results: Our cohort was obtained from 209 families enriched for BAV. After adjusting for age, body surface area, and sex, individuals with BAV had a statistically significant increase in all echocardiographic measurements (p < 0.006) except descending Ao and MVA. Individuals with BAV were at greater odds of having Ao dilation (OR = 4.44, 95% CI 2.93–6.72) than family members without BAV. All echocardiographic measurements exhibited moderate to strong heritability (0.25–0.53), and these estimates were not influenced by inclusion of BAV as a covariate. Bivariate genetic analyses supported that the genetic correlation between BAV and echo measures were not significantly different from zero. Conclusion: We show for the first time that echocardiographic measurements of Ao, pulmonary artery and MVA diameters are quantitative traits that exhibit significant heritability. In addition, our results suggest the presence of BAV independently influences the proximal Ao and pulmonary artery measures but not those in the descending Ao or MVA.

Bicuspid aortic valve leaflet morphology in relation to aortic root morphology: a study of 300 patients undergoing open-heart surgery

OBJECTIVE

There is an ongoing discussion regarding the mechanism of aortic dilatation in bicuspid aortic valve (BAV) disease, that is, is this a hemodynamic effect or related to an inborn weakness of the aortic wall? This study evaluated the possibility of BAV morphology being related to ascending aorta morphology as such a correlation would strengthen the idea that hemodynamic alterations cause the dilatation of the aorta.

METHODS

The morphology of the ascending aorta of 300 patients admitted for aortic valve and/or ascending aorta disease was evaluated by echocardiography and related to the surgeon's inspection of the aortic valve.

RESULTS

A tricuspid aortic valve (TAV), BAV, or unicuspid aortic valve (UAV) was present in 130, 160, and 10 patients, respectively. Ascending aortic aneurysm was more common in patients with BAV compared with TAV (36% and 12%, respectively; p < 0.001), while ectasia of the aorta was similarly common (8% in both groups). Aortic stenosis or regurgitation was equally distributed in TAV and BAV patients with normal aortas (p=0.82). When the aorta was dilated, aortic stenosis was predominantly associated with BAV (BAV 56%, TAV 4%; p < 0.001), while aortic regurgitation was more common in TAV (TAV 81%, BAV 29%; p<0.001). In BAV patients, fusion of the right- and left coronary cusp was predominant (74%) followed by right- and non-coronary cusp fusion (14%) and true BAV (fusion of the right- and left coronary cusp without remnant raphe; 11%) (p < 0.001). The relative distribution of ascending aortic aneurysm or ectasia was similar in all morphologically different BAV (p = 0.95).

CONCLUSIONS

In our study population, >50% of the patients admitted for surgery had a bicuspid valve. Aortic aneurysm was more common in BAV than in TAV patients. Aortic stenosis and aortic regurgitation were equally common in TAV and BAV with normal aortic dimensions, while aortic regurgitation was predominant in TAV with dilated aortas and aortic stenosis in BAV with dilated aortas. Dilatation of the aorta was similarly distributed regardless of BAV leaflet morphology. These findings support the idea of an intrinsic mechanisms underlying dilatation of the aorta in BAV patients.