Diagnostic power of aortic elastic properties in young patients with Marfan syndrome

Are aortic biomechanical properties early markers of dilatation in patients with Marfan syndrome? A systematic review and meta-analysis

Although tissue stiffness is known to play an important role in aortic dilatation, the current guidelines for offering preventative surgery in patients with Marfan syndrome rely solely on the aortic diameter. In this systematic review and meta-analysis, we analyze and compare literature on in vivo aortic stiffness measures in Marfan patients. Our aim is to assess the potential of these measurements as early indicators of aortic dilatation. Following the PRISMA guidelines, we collected literature on diameter and three in vivo stiffness measures: Pulse wave velocity (PWV), β -stiffness index (SI) and distensibility, at five different aortic locations in patients with Marfan syndrome. Results were reviewed and compared against each other. For meta-analysis, an augmented dataset was created by combining data from the literature. Regression with respect to age and statistical comparisons were performed. Thirty articles reporting data from 1925 patients with Marfan and 836 patients without Marfan were reviewed. PWV was found to be higher in Marfan, but only in dilated aortas. Distensibility was found to be lower even in non-dilated aortas, and its decrease was associated with higher chances of developing aortic dilatation. β -SI was higher in Marfan patients and was positively correlated with the rate of aortic dilatation, emphasizing its role as a valuable indicator. In our meta-analysis, all stiffness measures showed a significant variation with age. Distensibility and β -stiffness index were different in Marfan patients at all locations, and the difference was more pronounced after accounting for age-related variation. From the literature, β -SI and distensibility emerge as the best predictors of future aortic dilatation. Our meta-analysis quantifies age-related changes in aortic stiffness and highlights the importance of accounting for age in comparing these measurements. Missing diameter values in the literature limited our analysis. Further investigation of criteria combining stiffness and diameter is recommended to better assist clinical decisions for prophylactic surgery.

The predictive capability of aortic stiffness index for aortic dissection among dilated ascending aortas

OBJECTIVE

We created a finite element model to predict the probability of dissection based on imaging-derived aortic stiffness and investigated the link between stiffness and wall tensile stress using our model.

METHODS

Transthoracic echocardiogram measurements were used to calculate aortic diameter change over the cardiac cycle. Aortic stiffness index was subsequently calculated based on diameter change and blood pressure. A series of logistic models were developed to predict the binary outcome of aortic dissection using 1 or more series of predictor parameters such as aortic stiffness index or patient characteristics. Finite element analysis was performed on a subset of diameter-matched patients exhibiting patient-specific material properties.

RESULTS

Transthoracic echocardiogram scans of patients with type A aortic dissection (n = 22) exhibited elevated baseline aortic stiffness index when compared with aneurysmal patients' scans with tricuspid aortic valve (n = 83, P < .001) and bicuspid aortic valve (n = 80, P < .001). Aortic stiffness index proved an excellent discriminator for a future dissection event (area under the curve, 0.9337, odds ratio, 2.896). From the parametric finite element study, we found a correlation between peak longitudinal wall tensile stress and stiffness index (ρ = .6268, P < .001, n = 28 pooled).

CONCLUSIONS

Noninvasive transthoracic echocardiogram-derived aortic stiffness measurements may serve as an impactful metric toward predicting aortic dissection or quantifying dissection risk. A correlation between longitudinal stress and stiffness establishes an evidence-based link between a noninvasive stiffness parameter and stress state of the aorta with clinically apparent dissection events.

Young hearts, early risks: novel cardiovascular biomarkers in former very preterm infants at kindergarten age

BACKGROUND

Preterm birth is associated with long-term cardiovascular morbidity and mortality. In adults, fibroblast growth factor-23 (FGF-23), α-Klotho, and secretoneurin have all garnered attention as cardiovascular biomarkers, but their utility in pediatric populations has not yet been ascertained. The aim of this pilot study was to evaluate these novel cardiovascular biomarkers and their association with indicators of cardiovascular impairment in the highly vulnerable population of former very preterm infants.

METHODS

Five- to seven-year-old children born at < 32 weeks' gestation were eligible for the study. Healthy same-aged children born at term served as controls. Biomarkers were quantified in fasting blood samples, and echocardiographic measurements including assessment of aortic elastic properties were obtained.

RESULTS

We included 26 former very preterm infants and 21 term-born children in the study. At kindergarten age, former very preterm infants exhibited significantly higher plasma concentrations of biologically active intact FGF-23 (iFGF-23; mean 43.2 pg/mL vs. 29.1 pg/mL, p = 0.003) and secretoneurin (median 93.8 pmol/L vs. 70.5 pmol/L, p = 0.046). iFGF-23 inversely correlated with distensibility of the descending aorta.

CONCLUSION

In preterm-born children, iFGF-23 and secretoneurin both offer prospects as valuable cardiovascular biomarkers, potentially allowing for risk stratification and timely implementation of preventive measures.

IMPACT

Former very preterm infants have increased plasma concentrations of the novel cardiovascular biomarkers intact fibroblast growth factor-23 (iFGF-23) and secretoneurin at kindergarten age. Increases in iFGF-23 concentrations are associated with decreased distensibility of the descending aorta even at this early age. Monitoring of cardiovascular risk factors is essential in individuals with a history of preterm birth. Both iFGF-23 and secretoneurin hold promise as clinically valuable biomarkers for risk stratification, enabling the implementation of early preventive measures.

Ascending aorta mechanics and dimensions in aortopathy – from science to application

The ascending aorta has a unique microstructure and biomechanical properties that allow it to absorb energy during systole and return energy during diastole (Windkessel effect). Derangements in aortic architecture can result in changes to biomechanics and inefficiencies in function. Ultimately biomechanical failure may occur resulting in aortic dissection or rupture. By measuring aortic biomechanics with either in vivo or ex vivo methods, one may be able to predict tissue failure in patients with aortic disease such as aneurysms. An understanding of the biomechanical changes that lead to these tissue-level failures may help guide therapy, disease surveillance, surgical intervention, and aid in the development of new treatments for this deadly condition.

Effects of an exclusive human-milk diet in preterm neonates on early vascular aging risk factors (NEOVASC): study protocol for a multicentric, prospective, randomized, controlled, open, and parallel group clinical trial

Background

Preterm birth accounts for approximately 11% of all livebirths globally. Due to improvements in perinatal care, more than 95% of these infants now survive into adulthood. Research has indicated a robust association between prematurity and increased cardiovascular risk factors and cardiovascular mortality. While the innate adverse effects of prematurity on these outcomes have been demonstrated, therapeutic strategies on the mitigation of these concerning developments are lacking. The primary objective of the NEOVASC clinical trial is therefore to investigate whether the administration of a prolonged exclusive human-milk diet in preterm infants is capable of alleviating the harmful effects of preterm birth on the early development of cardiovascular risk factors.

Methods

The NEOVASC study is a multicentric, prospective, randomized, controlled, open, and parallel group clinical trial conducted in four Austrian tertiary neonatal care facilities. The purpose of the present trial is to investigate the effects of a prolonged exclusive human-milk-diet devoid of bovine-milk-based food components on cardiovascular and metabolic risk factors at 1, 2, and 5 years of corrected age. Primary outcomes include assessments of fasting blood glucose levels, blood pressure levels, and the distensibility of the descending aorta using validated echocardiographic protocols at 5 years of corrected age. The test group, which consists of 200 preterm infants, will therefore be compared to a control group of 100 term-born infants and a historical control group recruited previously.

Discussion

Given the emerging implications of an increased cardiovascular risk profile in the potentially growing population of preterm infants, further research on the mitigation of long-term morbidities in formerly preterm infants is urgently warranted. Further optimizing preterm infants’ nutrition by removing bovine-milk-based food components may therefore be an interesting approach worth pursuing.

Trial registration

ClinicalTrials.govNCT04413994. Registered on 4 June 2020.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-021-05445-9.

Insights on the Pathogenesis of Aneurysm through the Study of Hereditary Aortopathies

Thoracic aortic aneurysms (TAA) are permanent and localized dilations of the aorta that predispose patients to a life-threatening risk of aortic dissection or rupture. The identification of pathogenic variants that cause hereditary forms of TAA has delineated fundamental molecular processes required to maintain aortic homeostasis. Vascular smooth muscle cells (VSMCs) elaborate and remodel the extracellular matrix (ECM) in response to mechanical and biochemical cues from their environment. Causal variants for hereditary forms of aneurysm compromise the function of gene products involved in the transmission or interpretation of these signals, initiating processes that eventually lead to degeneration and mechanical failure of the vessel. These include mutations that interfere with transduction of stimuli from the matrix to the actin-myosin cytoskeleton through integrins, and those that impair signaling pathways activated by transforming growth factor-β (TGF-β). In this review, we summarize the features of the healthy aortic wall, the major pathways involved in the modulation of VSMC phenotypes, and the basic molecular functions impaired by TAA-associated mutations. We also discuss how the heterogeneity and balance of adaptive and maladaptive responses to the initial genetic insult might contribute to disease.

A scoping review presenting a wide variety of research on paediatric and adolescent patients with Marfan syndrome

Aim

The present study aimed to map and summarise the research on children, aged 0‐18 years, with Marfan syndrome, identify research gaps and point to research agendas.

Methods

A scoping review was systematically performed by searching multiple databases from January 1996 to April 2019. Primary studies presenting results on at least six individuals aged 0‐18 years with Marfan syndrome, diagnosed according to the Ghent nosology, were selected.

Results

From 2341 de‐duplicated records, 92 papers were included, mapped and described. Their topics were diagnostics (12%), cardiovascular matters (50%), skeletal matters (22%), ocular matters (9%), other medical aspects (5%) and psychosocial perspectives (2%). Most studies were from Europe and North America and published between 1999 and 2019 in subject‐specific or paediatric journals, while a few were published in genetics journals. All studies had quantitative designs, and very few were multicentre studies. Each study had six to 608 subjects for a total of approximately 5809.

Conclusion

A wide range of research topics on adolescent and paediatric Marfan syndrome was found, but qualitative studies and a focus on psychosocial matters were lacking. Future investigations addressing noncardiovascular consequences and patient experiences are needed, as well as studies reaffirming or replicating existing intervention study results.

Single-Cell Transcriptomic Profiling of Vascular Smooth Muscle Cell Phenotype Modulation in Marfan Syndrome Aortic Aneurysm

OBJECTIVE

To delineate temporal and spatial dynamics of vascular smooth muscle cell (SMC) transcriptomic changes during aortic aneurysm development in Marfan syndrome (MFS). Approach and Results: We performed single-cell RNA sequencing to study aortic root/ascending aneurysm tissue from Fbn1C1041G/+ (MFS) mice and healthy controls, identifying all aortic cell types. A distinct cluster of transcriptomically modulated SMCs (modSMCs) was identified in adult Fbn1C1041G/+ mouse aortic aneurysm tissue only. Comparison with atherosclerotic aortic data (ApoE-/- mice) revealed similar patterns of SMC modulation but identified an MFS-specific gene signature, including plasminogen activator inhibitor-1 (Serpine1) and Kruppel-like factor 4 (Klf4). We identified 481 differentially expressed genes between modSMC and SMC subsets; functional annotation highlighted extracellular matrix modulation, collagen synthesis, adhesion, and proliferation. Pseudotime trajectory analysis of Fbn1C1041G/+ SMC/modSMC transcriptomes identified genes activated differentially throughout the course of phenotype modulation. While modSMCs were not present in young Fbn1C1041G/+ mouse aortas despite small aortic aneurysm, multiple early modSMCs marker genes were enriched, suggesting activation of phenotype modulation. modSMCs were not found in nondilated adult Fbn1C1041G/+ descending thoracic aortas. Single-cell RNA sequencing from human MFS aortic root aneurysm tissue confirmed analogous SMC modulation in clinical disease. Enhanced expression of TGF-β (transforming growth factor beta)-responsive genes correlated with SMC modulation in mouse and human data sets.

CONCLUSIONS

Dynamic SMC phenotype modulation promotes extracellular matrix substrate modulation and aortic aneurysm progression in MFS. We characterize the disease-specific signature of modSMCs and provide temporal, transcriptomic context to the current understanding of the role TGF-β plays in MFS aortopathy. Collectively, single-cell RNA sequencing implicates TGF-β signaling and Klf4 overexpression as potential upstream drivers of SMC modulation.

Biomechanics of Aortic Dissection: A Comparison of Aortas Associated With Bicuspid and Tricuspid Aortic Valves

Background

Current methods for aortic dissection risk assessment are inadequate for patients with ascending aortic aneurysms associated with either bicuspid aortic valves (BAVs) or tricuspid aortic valves (TAVs). Biomechanical testing of aortic tissue may provide novel insights and biomarkers.

Methods and Results

From March 2017 to August 2019, aneurysmal ascending aortas (BAV=23, TAV=23) were collected from elective aortic surgery, normal aortas from transplant donors (n=9), and dissected aortas from surgery for aortic dissection (n=7). These aortas underwent delamination testing in simulation of aortic dissection. Biaxial tensile testing was performed to determine modulus of elasticity (aortic stiffness), and energy loss (a measure of efficiency in performing the Windkessel function). Delamination strength (S_d) was lowest in dissected aortas (18±6 mN/mm) and highest in normal aortas (58±16 mN/mm), and aneurysms fell in between, with greater S_d in the BAV group (37±10 mN/mm) than the TAV group (27±10 mN/mm) (P<0.001). Bicuspid aortopathy was associated with greater stiffness (P<0.001), while aneurysms with TAV demonstrated greater energy loss (P<0.001). S_d decreased by 7.8±1.2 mmol/L per mm per decade of life (r²=0.45, P<0.001), and it was significantly lower for patients with hypertension (P=0.001). S_d decreased by 6.1±2.1 mmol/L per mm with each centimeter increase in aortic diameter (r²=0.15, P=0.007). Increased energy loss was associated with decreased S_d (r²=0.41), whereas there was no relationship between S_d and aortic stiffness.

Conclusions

Aneurysms with BAV had higher S_d than those with TAV, suggesting that BAV was protective. Energy loss was lower in aneurysms with BAV, and inversely associated with S_d, representing a potential novel biomarker.

Divergent effects of canonical and non-canonical TGF-β signalling on mixed contractile-synthetic smooth muscle cell phenotype in human Marfan syndrome aortic root aneurysms

Aortic root aneurysm formation is a cardinal feature of Marfan syndrome (MFS) and likely TGF‐β driven via Smad (canonical) and ERK (non‐canonical) signalling. The current study assesses human MFS vascular smooth muscle cell (SMC) phenotype, focusing on individual contributions by Smad and ERK, with Notch3 signalling identified as a novel compensatory mechanism against TGF‐β‐driven pathology. Although significant ERK activation and mixed contractile gene expression patterns were observed by traditional analysis, this did not directly correlate with the anatomic site of the aneurysm. Smooth muscle cell phenotypic changes were TGF‐β‐dependent and opposed by ERK in vitro, implicating the canonical Smad pathway. Bulk SMC RNA sequencing after ERK inhibition showed that ERK modulates cell proliferation, apoptosis, inflammation, and Notch signalling via Notch3 in MFS. Reversing Notch3 overexpression with siRNA demonstrated that Notch3 promotes several protective remodelling pathways, including increased SMC proliferation, decreased apoptosis and reduced matrix metalloproteinase activity, in vitro. In conclusion, in human MFS aortic SMCs: (a) ERK activation is enhanced but not specific to the site of aneurysm formation; (b) ERK opposes TGF‐β‐dependent negative effects on SMC phenotype; (c) multiple distinct SMC subtypes contribute to a ‘mixed’ contractile‐synthetic phenotype in MFS aortic aneurysm; and (d) ERK drives Notch3 overexpression, a potential pathway for tissue remodelling in response to aneurysm formation.

Predissection-derived geometric and distensibility indices reveal increased peak longitudinal stress and stiffness in patients sustaining acute type A aortic dissection: Implications for predicting dissection

OBJECTIVE

To assess ascending aortic distensibility and build geometry and distensibility-based patient-specific stress distribution maps in patients sustaining type A aortic dissection (TAAD) using predissection noninvasive imaging.

METHODS

Review of charts from patients undergoing surgical repair of TAAD (n = 351) led to the selection of a subset population (n = 7) with 2 or more predissection computed tomography angiography scans and echocardiograms at least 1 year before dissection. Ascending aortic wall biomechanical properties (aortic strain, distensibility, and stiffness) were compared with age- and size-matched nondissected nonaneurysmal controls. Patient-specific aortic strain served as an input in aortic geometry-based simulated 3-dimensional reconstructions to generate longitudinal and circumferential wall stress maps. Inspection of perioperative dissection scans and intraoperative visual examination confirmed primary tear locations.

RESULTS

Predissection echocardiography revealed ascending aortas of patients sustaining TAAD to exhibit decreased aortic wall strain (14.50 ± 1.13% vs 8.49 ± 1.08%; P < .01), decreased distensibility (4.26 ± 0.44 vs 2.39 ± 0.33 10^-6 cm²·dyne^-1; P < .01), increased stiffness (3.84 ± 0.24 vs 7.48 ± 1.05; P < .001), and increased longitudinal wall stress (246 ± 22 vs 172 ± 37 kPa; P < .01). There was no significant difference in circumferential wall stress. Predissection computed tomography angiography models revealed overlap between regions of increased longitudinal wall stress and primary tear sites.

CONCLUSIONS

Using predissection imaging, we identified increased stiffness and longitudinal wall stress in ascending aortas of patients with dissection. Patient-specific imaging-derived biomechanical property maps like these may be instrumental toward designing better prediction models of aortic dissection potential.

Influence of Aortic Stiffness on Aortic-Root Growth Rate and Outcome in Patients With the Marfan Syndrome

The Pediatric Heart Network randomized trial of atenolol versus losartan in the Marfan syndrome showed no treatment differences in the rates of aortic-root growth or clinical outcomes. In this report we present treatment effects on aortic stiffness and determine whether baseline aortic stiffness predicts aortic-root growth and clinical outcomes. Echocardiograms at 0, 6, 12, 24, and 36 months from 608 subjects (6 months to 25 years) who met original Ghent criteria and had a maximum aortic-root z-score (ARz) >3 were centrally reviewed. Stiffness index (SI) and elastic modulus (EM) were calculated for aortic root and ascending aorta. Data were analyzed using multivariable mixed effects modeling and Cox regression. Heart rate-corrected aortic-root SI over 3 years decreased with atenolol but did not change with losartan (-0.298 ± 0.139 vs 0.141 ± 0.139/year, p = 0.01). In the entire cohort, above-median aortic-root SI (>9.1) and EM (>618 mm Hg) predicted a smaller annual decrease in ARz (p ≤0.001). Upper-quartile aortic-root EM (>914 mm Hg) predicted the composite outcome of aortic-root surgery, dissection, or death (hazard ratio 2.17, 95% confidence interval 1.02 to 4.63, p = 0.04). Crude 3-year event rates were 10.4% versus 3.2% for higher versus lower EM groups. In conclusion, atenolol was associated with a decrease in aortic-root SI, whereas losartan was not. Higher baseline aortic-root SI and EM were associated with a smaller decrease in ARz and increased risk for clinical outcomes. These data suggest that noninvasive aortic stiffness measures may identify patients at higher risk of progressive aortic enlargement and adverse clinical outcomes, potentially allowing for closer monitoring and more aggressive therapy.

Developmental Changes in Aortic Mechanical Properties in Normal Fetuses and Fetuses with Cardiovascular Disease

BACKGROUND

We hypothesized that fetal aortic mechanical properties assessed by aortic diameter (AoD) and flow show maturational changes during the gestational period, and that these properties are different in fetuses with congenital heart diseases and fetuses with normal development.

METHODS

Phasic changes in ascending AoD along with Doppler flow profile were measured in 84 consecutive normal fetuses (gestational age, 18-36 weeks) and in 30 consecutive fetuses with cardiovascular diseases (gestational age, 22-39 weeks).

RESULTS

AoD and cardiac output significantly increased with gestational age. Fetal aortic compliance (AC), assessed as (maximum AoD - minimum AoD)/stroke volume, significantly decreased with gestational age in normal fetuses, indicating maturational changes in aortic wall properties. Importantly, fetuses with Marfan syndrome and tetralogy of Fallot that exhibit "aortopathy" showed significantly lower AC than normal fetuses of the same gestational age, suggesting intrinsic abnormalities in aortic wall properties in these diseases. Fetuses with trisomy 18 and Noonan syndrome also had AC values below the normal ranges.

CONCLUSION

Measurements of phasic changes in fetal AoD and flow measurements can provide useful information about aortic mechanical properties and may help clarify abnormal arterial hemodynamics in pathologic conditions.

Long-term miR-29b suppression reduces aneurysm formation in a Marfan mouse model

Aortic root aneurysm formation and subsequent dissection and/or rupture remain the leading cause of death in patients with Marfan syndrome. Our laboratory has reported that miR‐29b participates in aortic root/ascending aorta extracellular matrix remodeling during early aneurysm formation in Fbn1^C1039G/+ Marfan mice. Herein, we sought to determine whether miR‐29b suppression can reduce aneurysm formation long‐term. Fbn1^C1039G/+ Marfan mice were treated with retro‐orbital LNA‐anti‐miR‐29b inhibitor or scrambled‐control‐miR before aneurysms develop either (1) a single dose prenatally (pregnant Fbn1^C1039G/+ mice at 14.5 days post‐coitum) (n = 8–10, each group) or (2) postnatally every other week, from 2 to 22 weeks of age, and sacrificed at 24 weeks (n = 8–10, each group). To determine if miR‐29b blockade was beneficial even after aneurysms develop, a third group of animals were treated every other week, starting at 8 weeks of age, until sacrificed (n = 4–6, each group). miR‐29b inhibition resulted in aneurysm reduction, increased elastogenesis, decreased matrix metalloproteinase activity and decreased elastin breakdown. Prenatal LNA‐anti‐miR‐29b inhibitor treatment decreased aneurysm formation up to age 32 weeks, whereas postnatal treatment was effective up to 16 weeks. miR‐29b blockade did not slow aortic growth once aneurysms already developed. Systemic miR‐29b inhibition significantly reduces aneurysm development long‐term in a Marfan mouse model. Drug administration during aortic wall embryologic development appears fundamental. miR‐29b suppression could be a potential therapeutic target for reducing aneurysm formation in Marfan syndrome patients.

Integrated strategy for in vitro characterization of a bileaflet mechanical aortic valve

Background

Haemodynamic performance of heart valve prosthesis can be defined as its ability to fully open and completely close during the cardiac cycle, neither overloading heart work nor damaging blood particles when passing through the valve. In this perspective, global and local flow parameters, valve dynamics and blood damage safety of the prosthesis, as well as their mutual interactions, have all to be accounted for when assessing the device functionality. Even though all these issues have been and continue to be widely investigated, they are not usually studied through an integrated approach yet, i.e. by analyzing them simultaneously and highlighting their connections.

Results

An in vitro test campaign of flow through a bileaflet mechanical heart valve (Sorin Slimline 25 mm) was performed in a suitably arranged pulsatile mock loop able to reproduce human systemic pressure and flow curves. The valve was placed in an elastic, transparent, and anatomically accurate model of healthy aorta, and tested under several pulsatile flow conditions. Global and local hydrodynamics measurements and leaflet dynamics were analysed focusing on correlations between flow characteristics and valve motion. The haemolysis index due to the valve was estimated according to a literature power law model and related to hydrodynamic conditions, and a correlation between the spatial distribution of experimental shear stress and pannus/thrombotic deposits on mechanical valves was suggested. As main and general result, this study validates the potential of the integrated strategy for performance assessment of any prosthetic valve thanks to its capability of highlighting the complex interaction between the different physical mechanisms that govern transvalvular haemodynamics.

Conclusions

We have defined an in vitro procedure for a comprehensive analysis of aortic valve prosthesis performance; the rationale for this study was the belief that a proper and overall characterization of the device should be based on the simultaneous measurement of all different quantities of interest for haemodynamic performance and the analysis of their mutual interactions.

Electronic supplementary material

The online version of this article (doi:10.1186/s12938-017-0314-2) contains supplementary material, which is available to authorized users.

Aortic Elastic Properties in Preschool Children Born Preterm

OBJECTIVE

Preterm birth predisposes children to the development of cardiovascular diseases in adulthood. The aim of this study was to characterize elastic properties of the aorta at preschool age and test the hypothesis that prematurity is associated with decreased aortic distensibility and increased stiffness, both of which are predictors of increased cardiovascular risk.

APPROACH AND RESULTS

In an observational study of 76 five- to seven-year-old children born at a gestational age <32 weeks and 79 term-born controls, elastic parameters of the ascending and descending abdominal aorta were determined noninvasively by means of M mode echocardiographic tracings and calculated using computerized wall contour analysis. Compared with children born at term, the preterm group showed significantly reduced distensibility and increased stiffness of the descending abdominal aorta. These results remained significant under multivariable adjustment for birth weight z score, maternal smoking in pregnancy, maternal education, family history of cardiovascular disease, breastfeeding, childhood nutrition, and current body mass index z score (multivariable odds ratios and 95% confidence intervals 5.1, 1.7-15.9; P=0.005 and 2.8, 1.0-7.9; P=0.046, respectively). Further adjustment for intravenous lipid therapy attenuated the strength of association. Elastic properties of the ascending aorta did not differ between the 2 study groups.

CONCLUSIONS

Children born preterm are characterized by decreased elastic properties of the descending abdominal aorta potentially attributable to impaired viscoelastic properties of and lipid damage to the aorta. Clinical follow-up of preterm infants with a focus on aortic elastic properties may be useful for tailoring early prevention programs and counteracting cardiovascular risk in adulthood.

NT-proBNP and diastolic left ventricular function in patients with Marfan syndrome

AIMS

Subclinical diastolic dysfuntion in patients with preclinical heart failure with preserved ejection fraction (HFpEF) has been demonstrated in patients with Marfan syndrome (MFS). We investigated the relationship between diastolic dysfunction and NT-proBNP levels in patients with MFS.

METHODS AND RESULTS

NT-proBNP, C-reactive protein (CRP) and diastolic function were assessed in 217 patients with MFS (31 ± 16 y, 110 f. and in 339 patients referred for suspected MFS in whom the diagnosis was ruled out according to the Ghent nosology (30 ± 15 y, 154 f). Assessment of cardiovascular remodeling, diastolic function in echocardiography, and NT-proBNP was analyzed with univariate analysis and multi-parameter analysis of covariance (MANCOVA). NT-proBNP was 70.6 ± 74.8 pg/ml in patients with Marfan syndrome and 58.4 ± 100.3 pg/ml in controls (p = 0.002, Kolmogorov-Smirnov). There were significant intergroup differences regarding end-diastolic left ventricular volume (p < 0.001), and aortic diameter (p < 0.001). The ratio of early diastolic mitral flow velocity (E) to early relaxation velocity in tissue Doppler (e'), E/e' (p < 0.001) was significantly higher in patients with Marfan syndrome than in controls, whereas e' (p < 0.001) and the ratio of E to inflow velocity during atrial contraction (A), E/A (p = 0.012) was significantly lower. Besides age and gender, diagnosis of MFS, diastolic function (e' and E/e'), Z-Score of aortic diameter, and left ventricular size were identified as significant independent parameters with impact on NT-proBNP levels.

CONCLUSIONS

MFS patients presenting with normal ejection fraction show disturbed diastolic function and higher NT-proBNP levels, which is partly explained by aortic Z-score. Assessment of diastolic function and NT-proBNP levels may therefore detect early abnormalities and guide surveillance and prevention management of patients with MFS.

Perspectives on the revised Ghent criteria for the diagnosis of Marfan syndrome

Three international nosologies have been proposed for the diagnosis of Marfan syndrome (MFS): the Berlin nosology in 1988; the Ghent nosology in 1996 (Ghent-1); and the revised Ghent nosology in 2010 (Ghent-2). We reviewed the literature and discussed the challenges and concepts of diagnosing MFS in adults. Ghent-1 proposed more stringent clinical criteria, which led to the confirmation of MFS in only 32%–53% of patients formerly diagnosed with MFS according to the Berlin nosology. Conversely, both the Ghent-1 and Ghent-2 nosologies diagnosed MFS, and both yielded similar frequencies of MFS in persons with a causative FBN1 mutation (90% for Ghent-1 versus 92% for Ghent-2) and in persons not having a causative FBN1 mutation (15% versus 13%). Quality criteria for diagnostic methods include objectivity, reliability, and validity. However, the nosology-based diagnosis of MFS lacks a diagnostic reference standard and, hence, quality criteria such as sensitivity, specificity, or accuracy cannot be assessed. Medical utility of diagnosis implies congruency with the historical criteria of MFS, as well as with information about the etiology, pathogenesis, diagnostic triggers, prognostic triggers, and potential complications of MFS. In addition, social and psychological utilities of diagnostic criteria include acceptance by patients, patient organizations, clinicians and scientists, practicability, costs, and the reduction of anxiety. Since the utility of a diagnosis or exclusion of MFS is context-dependent, prioritization of utilities is a strategic decision in the process of nosology development. Screening tests for MFS should be used to identify persons with MFS. To confirm the diagnosis of MFS, Ghent-1 and Ghent-2 perform similarly, but Ghent-2 is easier to use. To maximize the utility of the diagnostic criteria of MFS, a fair and transparent process of nosology development is essential.

Biomechanical properties of the Marfan's aortic root and ascending aorta before and after personalised external aortic root support surgery

Marfan syndrome is an inherited systemic connective tissue disease which may lead to aortic root disease causing dilatation, dissection and rupture of the aorta. The standard treatment is a major operation involving either an artificial valve and aorta or a complex valve repair. More recently, a personalised external aortic root support (PEARS) has been used to strengthen the aorta at an earlier stage of the disease avoiding risk of both rupture and major surgery. The aim of this study was to compare the stress and strain fields of the Marfan aortic root and ascending aorta before and after insertion of PEARS in order to understand its biomechanical implications. Finite element (FE) models were developed using patient-specific aortic geometries reconstructed from pre and post-PEARS magnetic resonance images in three Marfan patients. For the post-PEARS model, two scenarios were investigated-a bilayer model where PEARS and the aortic wall were treated as separate layers, and a single-layer model where PEARS was incorporated into the aortic wall. The wall and PEARS materials were assumed to be isotropic, incompressible and linearly elastic. A static load on the inner wall corresponding to the patients' pulse pressure was applied. Results from our FE models with patient-specific geometries show that peak aortic stresses and displacements before PEARS were located at the sinuses of Valsalva but following PEARS surgery, these peak values were shifted to the aortic arch, particularly at the interface between the supported and unsupported aorta. Further studies are required to assess the statistical significance of these findings and how PEARS compares with the standard treatment.

Aortic Involvement in Pediatric Marfan syndrome: A Review

Outlining specific protocols for the management of pediatric patients with Marfan syndrome has been challenging. This is mostly due to a dearth of clinical studies performed in pediatric patients. In Marfan syndrome, the major sources of morbidity and mortality relate to the cardiovascular system. In this review, we focus on aortic involvement seen in pediatric patients with Marfan syndrome, ranging from aortic dilatation to aortic rupture and heart failure. We discuss the histological, morphological, and pathogenetic basis of the cardiac manifestations seen in pediatric Marfan syndrome and use a specific case to depict our experienced range of cardiovascular manifestations. The survival for patients with Marfan syndrome may approach the expected survival for non-affected patients, with optimal management. With this potentiality in mind, we explore possible and actual management considerations for pediatric Marfan syndrome, examining both medical and surgical therapy modalities that can make the possibility of improved survival a reality.

2014 korean guidelines for appropriate utilization of cardiovascular magnetic resonance imaging: a joint report of the korean society of cardiology and the korean society of radiology

Cardiac magnetic resonance (CMR) imaging is now widely used in several fields of cardiovascular disease assessment due to recent technical developments. CMR can give physicians information that cannot be found with other imaging modalities. However, there is no guideline which is suitable for Korean people for the use of CMR. Therefore, we have prepared a Korean guideline for the appropriate utilization of CMR to guide Korean physicians, imaging specialists, medical associates and patients to improve the overall medical system performances. By addressing CMR usage and creating these guidelines we hope to contribute towards the promotion of public health. This guideline is a joint report of the Korean Society of Cardiology and the Korean Society of Radiology.

2014 Korean guidelines for appropriate utilization of cardiovascular magnetic resonance imaging: a joint report of the Korean Society of Cardiology and the Korean Society of Radiology

Cardiac magnetic resonance (CMR) imaging is now widely used in several fields of cardiovascular disease assessment due to recent technical developments. CMR can give physicians information that cannot be found with other imaging modalities. However, there is no guideline which is suitable for Korean people for the use of CMR. Therefore, we have prepared a Korean guideline for the appropriate utilization of CMR to guide Korean physicians, imaging specialists, medical associates and patients to improve the overall medical system performances. By addressing CMR usage and creating these guidelines we hope to contribute towards the promotion of public health. This guideline is a joint report of the Korean Society of Cardiology and the Korean Society of Radiology.

Echocardiographic methods, quality review, and measurement accuracy in a randomized multicenter clinical trial of Marfan syndrome

BACKGROUND

The Pediatric Heart Network is conducting a large international randomized trial to compare aortic root growth and other cardiovascular outcomes in 608 subjects with Marfan syndrome randomized to receive atenolol or losartan for 3 years. The authors report here the echocardiographic methods and baseline echocardiographic characteristics of the randomized subjects, describe the interobserver agreement of aortic measurements, and identify factors influencing agreement.

METHODS

Individuals aged 6 months to 25 years who met the original Ghent criteria and had body surface area-adjusted maximum aortic root diameter (ROOTmax) Z scores > 3 were eligible for inclusion. The primary outcome measure for the trial is the change over time in ROOTmaxZ score. A detailed echocardiographic protocol was established and implemented across 22 centers, with an extensive training and quality review process.

RESULTS

Interobserver agreement for the aortic measurements was excellent, with intraclass correlation coefficients ranging from 0.921 to 0.989. Lower interobserver percentage error in ROOTmax measurements was independently associated (model R(2) = 0.15) with better image quality (P = .002) and later study reading date (P < .001). Echocardiographic characteristics of the randomized subjects did not differ by treatment arm. Subjects with ROOTmaxZ scores ≥ 4.5 (36%) were more likely to have mitral valve prolapse and dilation of the main pulmonary artery and left ventricle, but there were no differences in aortic regurgitation, aortic stiffness indices, mitral regurgitation, or left ventricular function compared with subjects with ROOTmaxZ scores < 4.5.

CONCLUSIONS

The echocardiographic methodology, training, and quality review process resulted in a robust evaluation of aortic root dimensions, with excellent reproducibility.

Assessment of regional aortic stiffness with cardiac magnetic resonance imaging in a healthy Asian population

The aim of this study was to determine the normal values for aortic pulse wave velocity (PWV) and distensibility using cine and phase contrast cardiac magnetic resonance imaging (CMRI) in patients without cardiovascular risk factors. PWV and distensibility are indispensible predictors of global and regional cardiovascular risk. Regional heterogeneity in aortic stiffness plays an important role in the pathogenesis of cardiovascular disease. Contrary to global estimates of aortic PWV that are commonly measured with tonometry, CMRI has emerged as an important method for estimating regional PWV and distensibility. A total of 124 Korean patients, aged 20-79 years and free of cardiovascular risk factors, were categorized by age decade. Using cine and phase contrast sequences, the cross-sectional area for distensibility and average blood flow were measured at four aortic levels: the ascending, upper descending thoracic, lower thoracic and abdominal aorta. Regional PWV was determined in four aortic segments: proximal, descending thoracic, abdominal aorta and across the entire aorta. Distensibility at the four levels of the aorta from the ascending to distal (4.4 ± 2.5, 4.0 ± 1.6, 5.2 ± 1.9, and 3.3 ± 1.7 × 10(-3) mm/Hg, respectively) was higher in women (P < 0.001) and decreased with age. The regional PWV was highest in the descending thoracic aorta and increased with age. The present study is the first to show the heterogeneity in aortic PWV and distensibility, as well to provide normal values for these parameters using CMRI in an Asian sample.

Fibrillin-1 genetic deficiency leads to pathological ageing of arteries in mice

Fibrillin-1, the major component of extracellular microfibrils that associate with insoluble elastin in elastic fibres, is mainly synthesized during development and postnatal growth and is believed to guide elastogenesis. Mutations in the fibrillin-1 gene cause Marfan syndrome, a multisystem disorder characterized by aortic aneurysms and dissections. The recent finding that early deficiency of elastin modifies vascular ageing has raised the possibility that fibrillin-1 deficiency could also contribute to late-onset pathology of vascular remodelling. To address this question, we examined cardiovascular function in 3-week-old, 6-month-old, and 24-month-old mice that are heterozygous for a hypomorphic structural mutation of fibrillin-1 (Fbn1{+/mgΔ} mice). Our results indicate that Fbn1{+/mgΔ} mice, particularly those that are 24 months old, are slightly more hypotensive than wild-type littermates. Additionally, aneurysm and aortic insufficiency were more frequently observed in ageing Fbn1{+/mgΔ}$ mice than in the wild-type counterparts. We also noted substantial fragmentation and decreased number of elastic lamellae in the aortic wall of Fbn1{+/mgΔ} mice, which were correlated with an increase in aortic stiffness, a decrease in vasoreactivity, altered expression of elastic fibre-related genes, including fibrillin-1 and elastin, and a decrease in the relative ratio between tissue elastin and collagen. Collectively, our findings suggest that the heterozygous mgΔ mutation accelerates some aspects of vascular ageing and eventually leads to aortic manifestations resembling those of Marfan syndrome. Importantly, our data also indicate that vascular abnormalities in Fbn1{+/mgΔ} mice are opposite to those induced by elastin haploinsufficiency during ageing that affect blood pressure, vascular dimensions, and number of elastic lamellae.

The prevalence and clinical impact of obesity in adults with Marfan syndrome

BACKGROUND

Patients with Marfan syndrome characteristically have an asthenic body habitus and are considered to be exempt from the obesity epidemic.

OBJECTIVE

To examine the prevalence and clinical impact of obesity in a cohort of adults with Marfan syndrome.

METHODS

Fifty outpatients (30 female) with a mean (+/- SD) age of 38+/-13 years were studied. Demographic variables including previously identified risk factors for aortic dissection were recorded. Body mass index (BMI) was determined and patients were classified as normal (BMI less than 25 kgm2), overweight (BMI 25 kgm2 to 29.9 kgm2) or obese (BMI 30 kgm2 or greater). Other cardiovascular risk factors were examined. An adverse clinical outcome was defined as either the attainment of surgical criteria for aortic root replacement or the presence of aortic dissection.

RESULTS

A family history of aortic dissection was present in 13 (26%) patients. In 23 (46%) patients, there was no known family history of Marfan syndrome. Mean BMI was 25.4+/-7.4 kgm2, with 18 (36%) patients having an elevated BMI. Positive smoking status was present in 15 (30%), hypertension in 13 (26%) and hyperlipidemia in 19 (38%) patients. Adverse clinical outcome was present in 27 (54%) patients. Logistic regression analysis revealed only index case (OR 44; P<0.001) and higher BMI (OR 1.2; P=0.04) to be significantly and independently associated with increased risk of adverse clinical outcome.

CONCLUSIONS

Obesity is common in adults with Marfan syndrome and is associated with an increased risk of aortic complications.

Recommendations for cardiovascular magnetic resonance in adults with congenital heart disease from the respective working groups of the European Society of Cardiology

This paper aims to provide information and explanations regarding the clinically relevant options, strengths, and limitations of cardiovascular magnetic resonance (CMR) in relation to adults with congenital heart disease (CHD). Cardiovascular magnetic resonance can provide assessments of anatomical connections, biventricular function, myocardial viability, measurements of flow, angiography, and more, without ionizing radiation. It should be regarded as a necessary facility in a centre specializing in the care of adults with CHD. Also, those using CMR to investigate acquired heart disease should be able to recognize and evaluate previously unsuspected CHD such as septal defects, anomalously connected pulmonary veins, or double-chambered right ventricle. To realize its full potential and to avoid pitfalls, however, CMR of CHD requires training and experience. Appropriate pathophysiological understanding is needed to evaluate cardiovascular function after surgery for tetralogy of Fallot, transposition of the great arteries, and after Fontan operations. For these and other complex CHD, CMR should be undertaken by specialists committed to long-term collaboration with the clinicians and surgeons managing the patients. We provide a table of CMR acquisition protocols in relation to CHD categories as a guide towards appropriate use of this uniquely versatile imaging modality.

Quantitative sequence analysis of FBN1 premature termination codons provides evidence for incomplete NMD in leukocytes

We improved, evaluated, and used Sanger sequencing for quantification of single nucleotide polymorphism (SNP) variants in transcripts and gDNA samples. This improved assay resulted in highly reproducible relative allele frequencies (e.g., for a heterozygous gDNA 50.0+/-1.4%, and for a missense mutation-bearing transcript 46.9+/-3.7%) with a lower detection limit of 3-9%. It provided excellent accuracy and linear correlation between expected and observed relative allele frequencies. This sequencing assay, which can also be used for the quantification of copy number variations (CNVs), methylations, mosaicisms, and DNA pools, enabled us to analyze transcripts of the FBN1 gene in fibroblasts and blood samples of patients with suspected Marfan syndrome not only qualitatively but also quantitatively. We report a total of 18 novel and 19 known FBN1 sequence variants leading to a premature termination codon (PTC), 26 of which we analyzed by quantitative sequencing both at gDNA and cDNA levels. The relative amounts of PTC-containing FBN1 transcripts in fresh and PAXgene-stabilized blood samples were significantly higher (33.0+/-3.9% to 80.0+/-7.2%) than those detected in affected fibroblasts with inhibition of nonsense-mediated mRNA decay (NMD) (11.0+/-2.1% to 25.0+/-1.8%), whereas in fibroblasts without NMD inhibition no mutant alleles could be detected. These results provide evidence for incomplete NMD in leukocytes and have particular importance for RNA-based analyses not only in FBN1 but also in other genes.

Augmentation index relates to progression of aortic disease in adults with Marfan syndrome

BACKGROUND

Noninvasive applanation tonometry (APT) is useful to assess aortic stiffness and pulse wave reflection. Moreover, APT can predict outcome in many conditions such as arterial hypertension. In this study, we test whether APT measurements relate to progression of aortic disease in Marfan syndrome (MFS).

METHODS

We performed APT in 50 consecutive, medically treated adults with MFS (19 men and 31 women aged 32 +/- 13 years), who had not undergone previous cardiovascular surgery. During 22 +/- 16 months of follow-up, 26 of these patients developed progression of aortic disease, which we defined as progression of aortic root diameters >or=5 mm/annum (18 individuals), aortic surgery >or=3 months after APT (seven individuals), or onset of acute aortic dissection any time after APT (one individual).

RESULTS

Univariate Cox regression analysis suggested an association of aortic disease progression with age (P = 0.001), total cholesterol levels (P = 0.04), aortic root diameter (P = 0.007), descending aorta diameter (P = 0.01), aortic root ratio (P = 0.02), and augmentation index (AIx@HR75; P < 0.006). Multivariate Cox regression analysis confirmed an independent impact on aortic disease progression exclusively for baseline aortic root diameters (hazard ratio = 1.347; 95% confidence interval (CI) 1.104-1.643; P = 0.003) and AIx@HR75 (hazard ratio = 1.246; 95% CI 1.029-1.508; P = 0.02). In addition, Kaplan-Meier survival curve analysis illustrated significantly lower rates of aortic root disease progression both with lower AIx@HR75 (P = 0.025) and with lower pulse wave velocity (PWV) values (P = 0.027).

CONCLUSIONS

We provide evidence that APT parameters relate to aortic disease progression in medically treated patients with MFS. We believe that APT has a potential to improve risk stratification in the clinical management of MFS patients.

A comparison of echocardiographic techniques in determination of arterial elasticity in the pediatric population

BACKGROUND

Many methods are used to measure arterial elasticity in children using echocardiography. There is no data to support the equivalence of the different techniques. The goal of this study was to evaluate the reproducibility of several techniques used to measure arterial elasticity using echocardiography.

METHODS

Aortic distension in two different sites (arterial distension) through the cardiac cycle was measured by (four) two-dimensional (2D) and M-mode echocardiographic techniques in 20 children without significant structural heart disease. These measurements combined with noninvasive blood pressure measurements were used to calculate arterial elastic indices. Arterial elasticity was expressed in terms of distensibility and stiffness. Data were collected by two sonographers and interpreted by two reviewers. Paired Student's t-test and Pitman's test for equality of variance for correlated observations were used to detect differences between different sonographers, different reviewers, and different techniques.

RESULTS

No significant difference in the measured elasticity between sonographers or reviewers was observed. There was a somewhat increased variance in two of the four techniques evaluated. There was no significant difference in elasticity measured using different techniques to evaluate the same arterial site, although a significantly decreased elasticity was noted from measurements taken in the proximal ascending aorta as compared with the distal ascending aorta.

CONCLUSIONS

Many echocardiographic techniques produce reproducible measurements of arterial elasticity. There may be intrinsic differences in arterial elasticity between different segments of the ascending aorta, which have not been previously described in children with normal cardiac anatomy. Comparisons of data from separate studies must take these differences into account.

Impaired elastic properties of the ascending aorta persist within the first 3 years after neonatal coarctation repair

Abnormal elastic properties of the ascending aorta in patients with coarctation of the aorta (CoA) are already present in neonates before and after successful repair. To prove the midterm outcome for vascular pathology, a cohort of 15 patients was prospectively reevaluated. In this study, 15 patients after neonatal CoA repair (study group) and 15 healthy normal children (control group) were examined (mean age, 3.0 +/- 1.0 years). The aortic wall stiffness index and distensibility were calculated using ascending and abdominal aortic M-mode diameters and noninvasive estimation of pulse pressure. The study group was compared with the control group and with its own previously obtained pre- and postoperative measurements. After a mean follow-up period of 2.9 +/- 0.9 years, the elastic properties of the ascending aorta remained impaired in the study group compared with the control group (distensibility: 62 +/- 28 vs 94 +/- 34; p = 0.01; stiffness index: 4.4 +/- 1.9 vs 2.7 +/- 1.0; p = 0.008). At follow-up evaluation, the elasticity of the ascending aorta in the study group showed no change from the initial neonatal findings (distensibility: 63 +/- 24 vs 62 +/- 28; p = 0.82; stiffness index: 4.0 +/- 1.6 vs 4.4 +/- 1.9; p = 0.65). In both groups, descending aortic elasticity increased during the follow-up period. Our data suggest that the diminished elastic properties of the prestenotic arteries remain unchanged years after successful CoA repair. Comparisons with the neonatal data showed no evidence for remodeling of the ascending aorta in this group.

Usefulness of bicuspid aortic valve phenotype to predict elastic properties of the ascending aorta

Bicuspid aortic valve (BAV) affects about 0.5% to 2% of the population and predisposes patients to aortic dilation and dissection. We hypothesized that aortic size and elastic properties are related to BAV phenotype. In a retrospective study of 158 consecutive patients with BAV referred for echocardiography, the phenotype was defined as anterior-posterior (A-P) leaflet orientation or right-left (R-L) leaflet orientation. The 29 subjects with R-L BAV were matched 1:1 for age, gender, and grade of aortic valve dysfunction with 29 subjects with A-P BAV. Aortic dimensions were measured at the sinuses of Valsalva, ascending aorta, and aortic arch. Distensibility and stiffness index were calculated using cuff blood pressure. Mean age was 41.5 years (range 21 to 67), and 59% were men. Aortic diameter was larger with A-P BAV than R-L at the sinuses (mean +/- 1 SD 3.48 +/- 0.49 vs 3.06 +/- 0.59, p <0 .01) and smaller at the arch (2.34 +/- 0.40 vs 2.83 +/- 0.45, p <0.001). At the sinuses, A-P BAV had a higher stiffness index (median 12.98, range 2.78 to 42.07 vs 6.41, range 2.75 to 59.72, p <0.01) and lower distensibility. Stiffness index in the ascending aorta and arch (but not at the sinus) increased with age. In conclusion, A-P BAV is associated with a larger stiffer sinus of Valsalva and smaller arch diameter. The potential impact of BAV phenotype and aortic elasticity on clinical outcomes merits further study.

Different patterns of aortic wall elasticity in patients with Marfan syndrome: A noninvasive follow-up study

OBJECTIVE

Aortic complications determine the life expectancy of most patients with Marfan syndrome. To find out whether there is heterogenous aortic involvement among patients and, if there is, to characterize aortic patterns and response to long-term beta-blocker therapy, we investigated aortic elastic properties before and during beta-blocker treatment.

METHODS

In 46 patients with Marfan syndrome (age, 17.4 +/- 11.1 years) and 46 healthy control subjects, ascending and descending aortic elastic parameters were determined noninvasively before and after 39 +/- 16 months of beta-blocker treatment with atenolol.

RESULTS

Aortic diameters and distensibility distinguished Marfan patients and controls with a sensitivity of 85% and a specificity of 87%. Cluster analysis revealed 4 patterns of aortic phenotypic expression: (1) reduced ascending aortic elasticity (46% of patients), (2) diminished ascending and descending aortic elasticity (17%), (3) minimal alterations of ascending and descending aortic elasticity (20%), and (4) reduced descending aortic elasticity (17%). During follow-up, aortic elastic properties improved in 21 (70%) of 30 patients and deteriorated in 9 (30%) irrespective of beta-blocker dosage. Improvement was observed in 100% of patients (n = 7; age, 5.3 +/- 4.2 years) with end-diastolic aortic root diameters between 20 and 30 mm and in 61% of patients (14/23; age, 20.5 +/- 10.0 years) with root diameters between 30 and 52 mm.

CONCLUSIONS

Aortic elastic parameters distinguish between patients with Marfan syndrome and healthy controls and show the pattern of regional aortic involvement. Improvement or deterioration during follow-up can influence therapeutic decisions to prevent aortic dissection and rupture. Young age, small root diameter, and high distensibility are favorable prognostic factors.

Marfan syndrome: what internists and pediatric or adult cardiologists need to know

Marfan syndrome (MFS) is one of the most frequent connective tissue disorders, showing striking pleiotropism and clinical variability. There is autosomal dominant inheritance with complete penetrance but variable expression. Approximately 25% of MFS patients have no family history of the syndrome and represent sporadic cases due to new mutations. This hazardous condition is often associated with premature cardiovascular death unless surveillance and management are optimized. The fibrillin gene (FBN1) encodes the structure of the connective tissue protein fibrillin. MFS is caused by mutations in the fibrillin gene, located on chromosome 15 at locus 15q21. Fibrillin abnormalities reduce the structural integrity of different body systems, primarily involving the heart valves, blood vessels, lungs, bones, tendons, ligaments, cartilages, eyes, skin, spinal dura and the CNS. Patients with MFS are likely to have too little fibrillin within these structures, resulting in clinically relevant problems. For example, in the aortic wall, deficient fibrillin may trigger progressive aortic ectasia and may result in aortic dissection.

A bioinformatics framework for genotype–phenotype correlation in humans with Marfan syndrome caused by FBN1 gene mutations

Mutations in the human FBN1 gene are known to be associated with the Marfan syndrome, an autosomal dominant inherited multi-systemic connective tissue disorder. However, in the absence of solid genotype-phenotype correlations, the identification of an FBN1 mutation has only little prognostic value. We propose a bioinformatics framework for the mutated FBN1 gene which comprises the collection, management, and analysis of mutation data identified by molecular genetic analysis (DHPLC) and data of the clinical phenotype. To query our database at different levels of information, a relational data model, describing mutational events at the cDNA and protein levels, and the disease's phenotypic expression from two alternative views, was implemented. For database similarity requests, a query model which uses a distance measure based on log-likelihood weights for each clinical manifestation, was introduced. A data mining strategy for discovering diagnostic markers, classification and clustering of phenotypic expressions was provided which enabled us to confirm some known and to identify some new genotype-phenotype correlations.

Aortic wall mechanics in the Marfan syndrome assessed by transesophageal tissue Doppler echocardiography

The aim of this study was to investigate the value of tissue Doppler imaging (TDI) using transesophageal echocardiography (TEE) in assessing the elastic properties of the thoracic aorta in patients with Marfan's syndrome. Aortic distensibility, stiffness index, and pulse-wave velocity were calculated using M-mode data in a TEE short-axis view in 31 patients with Marfan's syndrome and 22 normal controls. Acceleration time, maximum wall expansion velocity (Vmax), and wall strain were determined from TDI tracings. Indexes derived from TDI differed at a greater level of significance than M-mode-derived indexes in patients with dilated and normal aortas. Significant predictors of aortic dilation were systolic blood pressure, aortic stiffness index, Vmax, and strain. Decreased aortic strain and Vmax and increased stiffness index were predictive of aortic dissection (odds ratios 4.5, 3.3, and 2.2). In conclusion, the TDI assessment of aortic wall mechanics is complementary to standard M-mode measurements in discriminating normal subjects from patients with Marfan's syndrome and is accurate in predicting aortic dilation and dissection.

Reduced aortic elastic properties in a child with Takayasu arteritis: case report and literature review

Takayasu arteritis (TA) is a chronic inflammatory vasculitis of the aorta and its major branches with a very low incidence in Europe and North America. Our objective was to determine the elastic properties of the affected ascending and descending aortic walls non-invasively in a 14-year-old Iraqi girl with a 3-year history of fever, fatigue, malaise and diffuse pain. Ultrasound and magnetic resonance angiography showed marked thickening of the aortic wall, dilatation of the aortic arch, and decreased luminal diameters of the abdominal aorta and both subclavian arteries, consistent with TA. Ascending and descending aortic elastic properties such as distensibility and stiffness index were markedly reduced compared to a group of healthy controls (n=39): ascending aortic distensibility was 20 kPa(-1) x 10(-3) versus 63+/-23 kPa(-1) x 10(-3) in controls, and the ascending aortic stiffness index 9.6 versus 3.5+/-1.3 in controls. Although the patient's general condition improved rapidly on oral prednisolone and azathioprine and inflammatory parameters normalised within 3 weeks, the aortic elastic parameters did not change during the first 2 weeks of anti-inflammatory treatment. Unfortunately, no further follow-up was possible.

CONCLUSION

In patients with Takayasu arteritis, non-invasive quantification of reduced aortic elastic properties can help to assess aortic involvement, and possibly to follow disease activity and vascular response to therapy.

Impaired elastic properties of the ascending aorta in newborns before and early after successful coarctation repair: proof of a systemic vascular disease of the prestenotic arteries?

BACKGROUND

Despite successful surgical correction, morbidity of patients with coarctation of the aorta is increased. It is well known that these patients have impaired elastic properties of the prestenotic arteries. To find out whether these abnormalities are primarily present or develop later, we studied 17 newborns before and early after surgical repair.

METHODS AND RESULTS

Aortic wall stiffness index and distensibility were calculated using ascending and abdominal aortic diameters determined by M-mode echocardiography and noninvasive estimation of aortic pulse pressure in the right arm and leg. Seventeen patients with aortic coarctation (mean age, 20+/-26 days) were compared with 17 normal neonates (mean age, 13+/-7 days) preoperatively and postoperatively (10+/-6 days after surgery). Ascending aortic distensibility in patients was significantly reduced preoperatively (79+/-58 versus 105+/-36; P=0.03) and postoperatively (65+/-24 versus 105+/-36; P<0.005). Preoperative and postoperative ascending aortic stiffness index was higher in patients (preoperative, 5.2+/-4.4 versus 2.7+/-0.9; P=0.04; postoperative, 4.0+/-1.6 versus 2.7+/-0.9; P<0.005). Elastic properties of the descending aorta did not differ preoperatively or postoperatively compared with those in normal subjects.

CONCLUSIONS

Elastic properties of the prestenotic aorta of patients with coarctation seem to be impaired primarily, even in neonates, and remain unchanged early after successful operation. Surgical correction does not resolve inborn pathology of the prestenotic aortic vascular bed.