Bicuspid aortic valve-associated aortopathy: update on biomarkers

Blood and Imaging Biomarkers in the Long-term Follow-up of Bicuspid Aortic Valve Patients

Background

Bicuspid aortic valve (BAV) is a common congenital heart defect. Patients with BAV are at risk for long-term complications such as valve stenosis and regurgitation. This study aimed to investigate sex differences in blood and imaging biomarkers and to describe the long-term prognostic value of blood and echocardiographic biomarkers.

Methods

Patients were included from 2 prospective observational cohort studies; they underwent venous blood sampling and transthoracic echocardiography including speckle tracking. Analyzed blood biomarkers were red-cell distribution width (RDW), creatinine, C-reactive protein (CRP), troponin T, N-terminal pro B-type natriuretic peptide (NT-proBNP), and transforming growth factor-beta (TGF-β). Sex differences were analyzed at baseline. Associations between biomarkers and arrhythmia-free and intervention-free survival were determined by Cox regression, adjusted for age and sex.

Results

A total of 182 patients with BAV were included: median age 34; interquartile range [IQR]: 23-46 years; 55.5% male. CRP, NT-proBNP, and RDW were higher in women, whereas creatinine, troponin T and TGF-β were higher among men. After a median follow-up time of 6.9 (IQR: 6.5-9.9) years, arrhythmia-free and intervention-free survival was, 81.0% and 73.1%, respectively. NT-proBNP was associated with both arrhythmia-free and intervention-free survival (hazard ratio [HR], 1.94, P = 0.005 and HR, 2.06, P = 0.002, respectively). On echocardiography higher left atrial (LA) size, left ventricular end-diastolic diameter (LVEDD), left ventricular (LV) mass index and E/e' ratio were associated with lower arrhythmia-free survival, whereas higher LA size, LV mass index, aortic valve peak velocity, and aortic regurgitation were associated with lower intervention-free survival.

Conclusions

Differences were observed in blood biomarkers between men and women with BAV. Besides LV systolic parameters, diastolic LV function and NT-proBNP should have a more prominent role as prognostic markers in clinical care.

2022 ACC/AHA guideline for the diagnosis and management of aortic disease: A report of the American Heart Association/American College of Cardiology Joint Committee on Clinical Practice Guidelines

AIM

The "2022 ACC/AHA Guideline for the Diagnosis and Management of Aortic Disease" provides recommendations to guide clinicians in the diagnosis, genetic evaluation and family screening, medical therapy, endovascular and surgical treatment, and long-term surveillance of patients with aortic disease across its multiple clinical presentation subsets (ie, asymptomatic, stable symptomatic, and acute aortic syndromes).

METHODS

A comprehensive literature search was conducted from January 2021 to April 2021, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Library, CINHL Complete, and other selected databases relevant to this guideline. Additional relevant studies, published through June 2022 during the guideline writing process, were also considered by the writing committee, where appropriate.

STRUCTURE

Recommendations from previously published AHA/ACC guidelines on thoracic aortic disease, peripheral artery disease, and bicuspid aortic valve disease have been updated with new evidence to guide clinicians. In addition, new recommendations addressing comprehensive care for patients with aortic disease have been developed. There is added emphasis on the role of shared decision making, especially in the management of patients with aortic disease both before and during pregnancy. The is also an increased emphasis on the importance of institutional interventional volume and multidisciplinary aortic team expertise in the care of patients with aortic disease.

Bicuspid aortic valve associated aortopathy: 2022 guideline update

PURPOSE OF REVIEW

Bicuspid aortic valve (BAV) disease is observed in 1-2% of the general population. In addition to valve-related complications (such as aortic stenosis and aortic regurgitation), individuals with BAV often develop dilatation of the proximal aorta (aortic root and ascending aorta), a condition termed BAV aortopathy. The development of BAV aortopathy can occur independent of valvular alterations and can lead to aneurysm formation, aortic dissection or aortic rupture. This review aims to update the clinician with an approach to BAV aortopathy decision making in keeping with the 2022 American College of Cardiology (ACC)/American Heart Association (AHA) Guideline recommendations.

RECENT FINDINGS

The ACC/AHA 2022 guidelines provide a contemporary and comprehensive approach to the diagnosis and treatment of aortic pathologies. We review the thresholds for replacement of the aortic root and/or ascending aorta along with the strength and level of evidence recommendations. We also review the various Class 2A and 2B recommendations for earlier intervention, which emphasize the importance of experienced surgeons, and multidisciplinary aortic teams (MATs).

SUMMARY

BAV aortopathy is a common and heterogenous clinical problem. The decision making around timing of intervention requires a personalized approach that is based on the aortic dimensions, valve function, rate of growth, family history, patient factors, and surgical experience within MATs.

2022 ACC/AHA Guideline for the Diagnosis and Management of Aortic Disease: A Report of the American Heart Association/American College of Cardiology Joint Committee on Clinical Practice Guidelines

AIM

The "2022 ACC/AHA Guideline for the Diagnosis and Management of Aortic Disease" provides recommendations to guide clinicians in the diagnosis, genetic evaluation and family screening, medical therapy, endovascular and surgical treatment, and long-term surveillance of patients with aortic disease across its multiple clinical presentation subsets (ie, asymptomatic, stable symptomatic, and acute aortic syndromes).

METHODS

A comprehensive literature search was conducted from January 2021 to April 2021, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Library, CINHL Complete, and other selected databases relevant to this guideline. Additional relevant studies, published through June 2022 during the guideline writing process, were also considered by the writing committee, where appropriate. Structure: Recommendations from previously published AHA/ACC guidelines on thoracic aortic disease, peripheral artery disease, and bicuspid aortic valve disease have been updated with new evidence to guide clinicians. In addition, new recommendations addressing comprehensive care for patients with aortic disease have been developed. There is added emphasis on the role of shared decision making, especially in the management of patients with aortic disease both before and during pregnancy. The is also an increased emphasis on the importance of institutional interventional volume and multidisciplinary aortic team expertise in the care of patients with aortic disease.

2022 ACC/AHA Guideline for the Diagnosis and Management of Aortic Disease: A Report of the American Heart Association/American College of Cardiology Joint Committee on Clinical Practice Guidelines

AIM

The "2022 ACC/AHA Guideline for the Diagnosis and Management of Aortic Disease" provides recommendations to guide clinicians in the diagnosis, genetic evaluation and family screening, medical therapy, endovascular and surgical treatment, and long-term surveillance of patients with aortic disease across its multiple clinical presentation subsets (ie, asymptomatic, stable symptomatic, and acute aortic syndromes).

METHODS

A comprehensive literature search was conducted from January 2021 to April 2021, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Library, CINHL Complete, and other selected databases relevant to this guideline. Additional relevant studies, published through June 2022 during the guideline writing process, were also considered by the writing committee, where appropriate.

STRUCTURE

Recommendations from previously published AHA/ACC guidelines on thoracic aortic disease, peripheral artery disease, and bicuspid aortic valve disease have been updated with new evidence to guide clinicians. In addition, new recommendations addressing comprehensive care for patients with aortic disease have been developed. There is added emphasis on the role of shared decision making, especially in the management of patients with aortic disease both before and during pregnancy. The is also an increased emphasis on the importance of institutional interventional volume and multidisciplinary aortic team expertise in the care of patients with aortic disease.

Aorta-specific DNA methylation patterns in cell-free DNA from patients with bicuspid aortic valve-associated aortopathy

BACKGROUND

The dilation of the aorta that occurs as a consequence of a congenitally bicuspid aortic valve (BAV) is associated with a risk of dissection, aneurysm or rupture. With progressive aortopathy, surgery is often recommended, but current patient selection strategies have limitations. A blood-based assay to identify those who would most benefit from prophylactic surgery would be an important medical advance. In a proof-of-concept study, we sought to identify aorta-specific differentially methylated regions (DMRs) detectable in plasma cell-free DNA (cfDNA) obtained from patients undergoing surgery for BAV-associated aortopathy.

METHODS

We used bioinformatics and publicly available human methylomes to identify aorta-specific DMRs. We used data from 4D-flow cardiac magnetic resonance imaging to identify regions of elevated aortic wall shear stress (WSS) in patients with BAV-associated aortopathy undergoing surgery and correlated WSS regions with aortic tissue cell death assessed using TUNEL staining. Cell-free DNA was isolated from patient plasma, and levels of candidate DMRs were correlated with aortic diameter and aortic wall cell death.

RESULTS

Aortic wall cell death was not associated with maximal aortic diameter but was significantly associated with elevated WSS. We identified 24 candidate aorta-specific DMRs and selected 4 for further study. A DMR on chromosome 11 was specific for the aorta and correlated significantly with aortic wall cell death. Plasma levels of total and aorta-specific cfDNA did not correlate with aortic diameter.

CONCLUSIONS

In a cohort of patients undergoing surgery for BAV-associated aortopathy, elevated WSS created by abnormal flow hemodynamics was associated with increased aortic wall cell death which supports the use of aorta-specific cfDNA as a potential tool to identify aortopathy and stratify patient risk.

Bicuspid Aortic Valve Is Associated with Less Coronary Calcium and Coronary Artery Disease Burden

(1) Background. Bicuspid aortic valve (BAV) is associated with genetic defects (NOTCH 1, GATA 5) and aortopathy. Differences in the flow patterns and a genetic predisposition could also affect coronary arteries. The objective was to assess the coronary artery calcium score (CACS) and coronary artery disease (CAD) burden by coronary computed tomography angiography (CTA) in patients with BAV stenosis, as compared to stenotic tricuspid aortic valves (TAV). (2) Methods. A retrospective case-control study. A total of 47 patients with BAV stenosis (68.9 years ± 12.9, 38.3% females) who underwent CTA were matched with 47 TAV stenosis patients for age, gender, smoking, arterial hypertension, dyslipidemia, diabetes, body-mass-index and chronic kidney disease. (3) Results. The coronary artery calcium score (CACS) was lower in BAV (237.4 vs. 1013.3AU; p < 0.001) than in TAV, and stenosis severity was less (CAD-RADTM: p < 0.001). More patients with BAV had CACS zero (27.7% vs. 0%; p < 0.001). The majority (68.1%) of patients with BAV had no or non-obstructive CAD but only 25.5% of TAV (p < 0.001). Obstructive CAD (>50% stenosis) by CTA was more frequently observed in patients with TAV (68.1%; p < 0.001). (4) Conclusions and Relevance. Patients with BAV stenosis have markedly less coronary calcium and less severe coronary stenosis. CTA succeeds to rule out obstructive CAD in the majority of BAV, with adherent implications for TAVR planning.

Recurrent germline mutations as genetic markers for aortic root dilatation in bicuspid aortic valve patients

Bicuspid aortic valve (BAV) is characterized by elevated risk of aortic dilatation and aneurysm. Although genetic susceptibility is suspected to influence on the development of BAV aortopathy, clinical application of genetic markers still needs validation in BAV entities with strictly defined phenotypic features. The 'root phenotype' represents a young, male predominant, and severely aortic regurgitant BAV population prone to aortic root dilatation. The present study launched a two-step genetic survey to evaluate the clinical significance of germline genetic markers in BAV patients. The whole-exome sequencing (WES) cohort consisted of 13 BAV patients with 'root phenotype' under the age of 40 years. We identified 28 different heterozygous missense mutations in 19 genes from the WES cohort, among which six variants (COL1A2 R882C, COL5A1 I1161F, ACVRL1 R218W, NOTCH1 P1227S, MYLK S243W, MYLK D717Y) were identified as pathogenic variants via unanimous agreement of in silico prediction tool analysis, and three variants (C1R I345L, TGFBR2 V216I, FBN2 G475V) were identified as recurrent variants. The panel of nine genetic markers was tested in an independent validation cohort of 154 BAV patients consecutively included from January to May 2018 in our institution. The validation cohort demonstrated 71.4% male predominance and the average age of 57 ± 13 years, among which 26.6% showed aortic root dilatation and 66.9% ascending aortic dilatation. Genetic markers were found in 32 patients, including 18 with C1R I345L, 11 with TGFBR2 V216I, 2 with FBN2 G475V, and 1 with both TGFBR2 V216I and MYLK D717Y. BAV patients carrying these genetic markers demonstrated younger age [(51 ± 12) vs. (58 ± 13) years, P = 0.014], more moderate to severe aortic regurgitation (56.2% vs. 33.6%, P = 0.019), elevated prevalence of mitral valve prolapse (9.4% vs. 0.8%, P = 0.028) and aortic root dilatation (62.5% vs. 17.2%, P < 0.001) but not ascending aortic dilatation than those without these markers. The early-onset 'root phenotype' entities displayed great value for BAV genetic surveys. As one of the promising complements of the current risk stratification system, recurrent germline mutations in TGFBR2, C1R, FBN2 genes could be identified and applied as genetic markers of elevated susceptibility for aortic root but not ascending aortic dilatation among BAV patients.

Blood biomarkers in patients with bicuspid aortic valve disease

BACKGROUND

Patients with a bicuspid aortic valve (BAV) are at risk of developing valve deterioration and aortic dilatation. We aimed to investigate whether blood biomarkers are associated with disease stage in patients with BAV.

METHODS

Serum levels of high sensitivity C-reactive protein (hsCRP), high sensitivity troponin T (hsTnT), N-terminal pro-B-type natriuretic peptide (NT-proBNP), and total transforming growth factor-beta 1 (TGF-ß1) were measured in adult BAV patients with valve dysfunction or aortic pathology. Age-matched general population controls were included for TGFß-1 measurements. Correlation analyses and multivariable linear regression were used to determine the association between (2log-transformed) biomarker levels and aortic valve regurgitation, aortic valve stenosis, aortic dilatation, or left ventricular function.

RESULTS

hsCRP and hsTnT were measured in the total group of 183 patients (median age 34 years, 25th-75th percentile 23-46), NT-proBNP in 162 patients, and TGF-ß1 beta in 108 patients. Elevated levels of NT-proBNP were found in 20% of the BAV patients, elevated hsTnT in 6%, and elevated hsCRP in 7%. Higher hsTnT levels were independently associated with aortic regurgitation [odds ratio per doubling (OR_2log) 1.34, 95% CI 1.01;1.76] and higher NT-proBNP levels with aortic valve maximal velocity (ß_2log 0.17, 95%CI 0.07;0.28) and aortic regurgitation (OR_2log 1.41, 95%CI 1.11;1.79). Both BAV patients with (9.9 ± 2.7 ng/mL) and without aortic dilatation (10.4 ± 2.9 ng/mL) showed lower TGF-ß1 levels compared to general population controls (n = 85, 11.8 ± 3.2 ng/mL).

CONCLUSIONS

Higher NT-proBNP and hsTNT levels were associated with aortic valve disease in BAV patients. TGF-ß1 levels were lower in BAV patients than in the general population, and not related to aortic dilatation. Longitudinal data are needed to further investigate the prognostic value of biomarkers in these patients.

Risk Stratification in Bicuspid Aortic Valve Aortopathy: Emerging Evidence and Future Perspectives

The current management of aortic dilatation associated with congenital bicuspid aortic valve (bicuspid aortic valve aortopathy) is based on dimensional parameters (diameter of the aneurysm, growth of the diameter over time) and few other criteria. The disease is however heterogeneous in terms of natural and clinical history and risk of acute complications, ie aortic dissection. Dimensional criteria are now admitted to have limited value as predictors of such complications. Thus, novel principles for risk stratification have been recently investigated, including phenotypic criteria, flow-related metrics, and circulating biomarkers. A systematization of the typical anatomoclinical forms that the aortopathy can assume has led to the identification of the more severe root phenotype, associated with higher risk of progression of the aneurysm and possible higher aortic dissection risk. Four-dimensional-flow magnetic resonance imaging studies are searching for potentially clinically significant metrics of flow derangement, based on the recognized association of local abnormal shear stress with wall pathology. Other research initiatives are addressing the question whether circulating molecules could predict the presence or, more importantly, the future development of aortopathy. The present review summarizes the latest progresses in the knowledge on risk stratification of bicuspid aortic valve aortopathy, focusing on critical aspects and debated points.

Novel Approaches for BAV Aortopathy Prediction-Is There a Need for Cohort Studies and Biomarkers?

Bicuspid aortic valve (BAV) disease is the most common congenital malformation of the human heart with a prevalence of 1–2% in the general population. More than half of patients with a BAV present with a dilated proximal aorta (so-called bicuspid aortopathy) which is associated with an enhanced risk of life-threatening aortic complications. Up to now, the pathogenesis of bicuspid aortopathy as well as the risk stratification of aortic complications has not yet been sufficiently clarified. Recent findings have shown that bicuspid aortopathy features phenotypic heterogeneity. Two distinct valvulo-aortic phenotypes, the so-called root phenotype, as well as a dilation of the tubular ascending aorta, coincide with a significantly different risk for aortal complications. However, the phenotype-based classification that is only based on these two clinical forms is not sufficient to estimate the risk of aortal complications in a prognostically relevant way. Therefore, there is growing clinical interest to assess novel approaches in BAV research and to introduce circulating biomarkers as an elegant diagnostic tool to improve risk stratification in BAV aortopathy. A large scale epidemiological cohort study, ranking from apparently healthy individuals to disease patients, and comprehensive biobanks provide the opportunity to study BAV disease and its complications and to identify novel biomarkers for BAV aortopathy surveillance and prognosis. Firstly, the data indicate that several protein-based biomarkers and non-coding RNA molecules, in particular circulating microRNAs, can serve as relevant molecular biomarkers to predict the course of BAV-associated aortopathy. Here, we review the current literature and knowledge about BAV from a clinical point of view, and report about novel approaches in BAV biomarker research.