Arabidopsis seeds altered in the circadian clock protein TOC1 are characterized by higher level of linolenic acid

The circadian clock plays a critical role in regulating plant physiology and metabolism. However, the way in which the clock impacts the regulation of lipid biosynthesis in seeds is partially understood. In the present study, we characterized the seed fatty acid (FA) and glycerolipid (GL) compositions of pseudo-response regulator mutants. Among these mutants, toc1 (timing of cab expression 1) exhibited the most significant differences compared to control plants. These included an increase in total FA content, characterized by elevated levels of linolenic acid (18:3) along with a reduction in linoleic acid (18:2). Furthermore, our findings revealed that toc1 developing seeds showed increased expression of genes related to FA metabolism. Our results show a connection between TOC1 and lipid metabolism in Arabidopsis seeds.

Mutation of AtPME2, a pH-Dependent Pectin Methylesterase, Affects Cell Wall Structure and Hypocotyl Elongation

Pectin methylesterases (PMEs) modify homogalacturonan's chemistry and play a key role in regulating primary cell wall mechanical properties. Here, we report on Arabidopsis AtPME2, which we found to be highly expressed during lateral root emergence and dark-grown hypocotyl elongation. We showed that dark-grown hypocotyl elongation was reduced in knock-out mutant lines as compared to the control. The latter was related to the decreased total PME activity as well as increased stiffness of the cell wall in the apical part of the hypocotyl. To relate phenotypic analyses to the biochemical specificity of the enzyme, we produced the mature active enzyme using heterologous expression in Pichia pastoris and characterized it through the use of a generic plant PME antiserum. AtPME2 is more active at neutral compared to acidic pH, on pectins with a degree of 55-70% methylesterification. We further showed that the mode of action of AtPME2 can vary according to pH, from high processivity (at pH8) to low processivity (at pH5), and relate these observations to the differences in electrostatic potential of the protein. Our study brings insights into how the pH-dependent regulation by PME activity could affect the pectin structure and associated cell wall mechanical properties.

Overview and Management of the Most Common Eukaryotic Diseases of Flax (Linum usitatissimum)

Flax is an important crop cultivated for its seeds and fibers. It is widely grown in temperate regions, with an increase in cultivation areas for seed production (linseed) in the past 50 years and for fiber production (fiber flax) in the last decade. Among fiber-producing crops, fiber flax is the most valuable species. Linseed is the highest omega-3 oleaginous crop, and its consumption provides several benefits for animal and human health. However, flax production is impacted by various abiotic and biotic factors that affect yield and quality. Among biotic factors, eukaryotic diseases pose a significant threat to both seed production and fiber quality, which highlights the economic importance of controlling these diseases. This review focuses on the major eukaryotic diseases that affect flax in the field, describing the pathogens, their transmission modes and the associated plant symptoms. Moreover, this article aims to identify the challenges in disease management and provide future perspectives to overcome these biotic stresses in flax cultivation. By emphasizing the key diseases and their management, this review can aid in promoting sustainable and profitable flax production.

Pathogen Stopping and Metabolism Modulation Are Key Points to Linum usitatissimum L. Early Response against Fusarium oxysporum

Fusarium oxysporum is the one of the most common and impactful pathogens of flax. Cultivars of flax that show resistance to this pathogen have previously been identified. To better understand the mechanisms that are responsible for this resistance, we conducted time-lapse analysis of one susceptible and one resistant cultivar over a two-week period following infection. We also monitored changes in some metabolites. The susceptible cultivar showed a strong onset of symptoms from 6 to 8 days after inoculation, which at this time point, was associated with changes in metabolites in both cultivars. The resistant cultivar maintained its height and normal photosynthetic capacity but showed a reduced growth of its secondary stems. This resistance was correlated with the containment of the pathogen at the root level, and an increase in some metabolites related to the phenylpropanoid pathway.

Sphingomonas sediminicola Is an Endosymbiotic Bacterium Able to Induce the Formation of Root Nodules in Pea (Pisum sativum L.) and to Enhance Plant Biomass Production

The application of bacterial bio-inputs is a very attractive alternative to the use of mineral fertilisers. In ploughed soils including a crop rotation pea, we observed an enrichment of bacterial communities with Sphingomonas (S.) sediminicola. Inoculation experiments, cytological studies, and de novo sequencing were used to investigate the beneficial role of S. sediminicola in pea. S. sediminicola is able to colonise pea plants and establish a symbiotic association that promotes plant biomass production. Sequencing of the S. sediminicola genome revealed the existence of genes involved in secretion systems, Nod factor synthesis, and nitrogenase activity. Light and electron microscopic observations allowed us to refine the different steps involved in the establishment of the symbiotic association, including the formation of infection threads, the entry of the bacteria into the root cells, and the development of differentiated bacteroids in root nodules. These results, together with phylogenetic analysis, demonstrated that S. sediminicola is a non-rhizobia that has the potential to develop a beneficial symbiotic association with a legume. Such a symbiotic association could be a promising alternative for the development of more sustainable agricultural practices, especially under reduced N fertilisation conditions.

Impact of obesity on morbidity and oncologic outcomes after total mesorectal excision for mid and low rectal cancer

BACKGROUND

A recent meta-analysis showed that obesity increased the conversion rate and postoperative morbidity of rectal cancer surgery, but did not influence pathological results. However, this meta-analysis included patients with cancer of the upper rectum and had many biases. The aim of the present retrospective study was to investigate the impact of obesity, defined as a body mass index (BMI) ≥ 30 kg/m², on postoperative morbidity and short- and long-term oncologic outcomes of total mesorectal excision for mid and low rectal cancer in consecutive patients.

METHODS

This study included all eligible patients who were operated on for mid and lower rectal cancer between 1999 and 2018 in our hospital. We compared 90-day postoperative morbidity and mortality, and short- and long-term oncologic outcomes between obese and non-obese patients.

RESULTS

Three hundred and ninety patients [280 males, mean age 65.7 ± 11.3 years, 59 obese individuals (15.1%)] were included. There was no difference in the 90-day mortality rate between obese and non-obese groups (p = 0.068). There was a difference in the overall 90-day morbidity rate between the obese and non-obese groups that disappeared after propensity score matching of the patients. There was no difference in short-term oncological parameters, with a median follow-up of 43 (20-84) months, and there were no significant differences in disease-free and overall survival between obese and non-obese patients (p = 0.42 and p = 0.11, respectively).

CONCLUSIONS

Obesity does not affect the 90-day morbidity rate, or short- and long-term oncologic results in patients operated on for mid and lower rectal cancer.

Atrial-specific reduction of Kir2.1 channel pore diameter in addition to loss of inward-going rectification underlies inducible atrial fibrillation in a mouse model of short QT syndrome type 3

Introduction

Short QT Syndrome Type 3 (SQTS3) is an extremely rare arrhythmogenic disease caused by gain-of-function mutations in the KCNJ2 gene coding the inward rectifier potassium channel Kir2.1. We investigated arrhythmogenic mechanisms associated with a de-novo mutation (E299V) in Kir2.1 in an 11-year-old boy presenting an extremely abbreviated QT interval, paroxysmal atrial fibrillation, and mild left ventricular dysfunction. Amino acid E299 in the Kir2.1 sequence is necessary for polyamine binding induced inward rectification.

Purpose

Test the hypothesis that Kir2.1E299V induces reduced conductance and lack of rectification that causes electrical defects in atrial cardiomyocytes, predisposing patients to atrial arrhythmias.

Methods

We used intravenous adeno-associated virus-mediated gene transfer to generate mice expressing wild-type (WT) and the E299V mutant protein. We used ECG, intracardiac stimulation, patch-clamp, molecular biology and computational modelling to characterize the models and study arrhythmia mechanisms in the atria and ventricles.

Results

We confirmed WT or mutant Kir2.1 gene expression specifically in the mouse heart. On ECG, the corrected QT (QTc) interval of Kir2.1E299V mice was significantly shorter than Kir2.1WT mice (p<0.0001). The PR interval in Kir2.1E299V was also significantly shorter than WT mice (p<0.0001). On intracardiac stimulation, the largest proportion of arrhythmic events occurred in the atria, as 7 out of 9 Kir2.1E299V mice presented >1 second atrial flutter/fibrillation, while only 2 out of 10 Kir2.1WT mice showed this type of arrhythmia (p=0.023). On patch clamping, both atrial and ventricular cardiomyocytes expressing Kir2.1E299V had extremely abbreviated action potential durations (APD90) at all frequencies studied (p<0.0001). The current/voltage relation of ventricular Kir2.1E299V cardiomyocytes revealed an absence of inward-going rectification and increased IK1 at voltages positive to −80 mV compared to Kir2.1WT cardiomyocytes (p<0.0001). In contrast, while in the atrial Kir2.1E299V cardiomyocytes the outward IK1 was increased at voltages positive to −80 mV with loss of rectification, IK1 was significantly reduced at voltages negative to −80 mV (p<0.0001), suggesting a loss of function leading to atrial arrhythmia inducibility. A higher proportion of Kir2.2 at atrial level and atomic in-silico 3D simulations suggested that the mutation impaired polyamine block of the Kir2.1E299V-Kir2.2 channel while reducing the pore diameter.

Conclusions

This first in-vivo mouse model of cardiac-specific SQTS3 recapitulates the electrophysiological phenotype of a patient with the Kir2.1E299V mutation. The mutation results in a Kir2.1 gain-of-function mediated by and absence of rectification. The predominant arrhythmias induced in these SQTS3 mice were supraventricular likely due to the combined lack of inward rectification and atrial-specific reduced pore diameter of the Kir2.1E299V-Kir2.2 channel.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): La Caixa FoundationLa Maratό TV3 Foundation

Mapping of thoracic aorta growth rate on serial self-navigated 3D whole-heart magnetic resonance angiographies by image registration

Introduction

Accurate and reproducible assessment of aortic diameters and their growth rate is of key importance for the management of patients with thoracic aortic aneurysms [1,2]. It has been recently shown that image registration permits the assessment of progressive aortic dilation on ECG-gated contrast-enhanced CT angiography, outperforming manual quantification and allowing for 3D aortic size and growth mapping [3]. However, exposure to radiation makes it convenient to limit the use of CT for serial follow-up, especially in young patients. Self-navigated 3D whole-heart CMR acquisitions provides excellent image quality overcoming these limitations [4].

Purpose

To evaluate the accuracy and reproducibility of registration-based assessment of aortic dilation using self-navigated 3D whole-heart CMR acquisitions.

Methods

Fifteen patients with two self-navigated 3D whole-heart CMR images obtained at least 1 year apart were included. Aortic root and thoracic aorta diameters were measured by 2 independent observers both manually (multiplanar reconstruction) and with the registration-based technique. To perform registration-based assessment, the aorta was semi-automatically segmented and typical anatomical landmarks were placed by each observer at baseline [3]. Geometrical mapping between baseline and follow-up acquisitions was obtained using deformable image registration, and applied to the baseline aortic surface points to obtain their location at follow-up. Finally, aortic diameters and their growth rate were automatically measured and used to calculated 3D aortic dilation maps. Agreement between techniques and their inter-observer reproducibility were calculated.

Results

Patients age was 27.2±14.5 years and 40% were male. Mean follow-up duration was 2.7±1.6 years. Compared to manual assessment, the registration-based technique presented low bias and excellent agreement for aortic diameters (Table 1), and low bias and moderate agreement for growth rates both in the aortic root and the thoracic aorta (Table, Fig. 1A). The techniques presented similar inter-observer reproducibility in the assessment of aortic diameters (Table 1), while the registration-based method demonstrated much higher inter-observer reproducibility in the assessment of growth rates in the aortic root and the thoracic aorta (Table 1, Fig. 1A and B). Three-dimensional mapping of thoracic aortic diameters and growth was highly reproducible (mean regional ICC=0.90 for diameters; 0.82 for growth rate).

Conclusion

The assessment of the dilation rate of the thoracic aorta via registration of serial self-navigated 3D whole-heart CMR acquisitions is accurate and reproducible in the aortic root and the thoracic aorta. Thus, it allows to assess local aortic growth without the drawbacks of CT.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Instituto de Salud Carlos III and Ministerio de Ciencia e Innovaciόn (Spain)

Mitral valve prolapse but no mitral annular disjunction is related to mitral regurgitation progression in patients with Marfan syndrome

Funding Acknowledgements

Type of funding sources: None.

Background

Mitral annular disjunction (MAD) is a structural abnormality of the mitral annular fibrosus characterized by a separation between the atrial wall-mitral valve junction, and the left ventricular attachment (1,2). It has been associated with mitral valve prolapse (MVP). Limited data is available regarding the impact of the presence of MVP on the evolution of mitral regurgitation in these syndromic entities.

Purpose

To evaluate the prevalence of MAD, PMV, and the combination of both in patients with syndromic hereditary thoracic aortic disease (HTAD) including Marfan (MFS), Loeys-Dietz (LDS), and vascular Ehlers-Danlos syndromes (vEDS), and its relationship with mitral regurgitation (MR) severity and the need for mitral surgery at the follow-up.

Methods

Adult patients with syndromic HTAD seen at our specialized unit were retrospectively included. The presence of MAD, MVP, and significant MR at the first echocardiogram were evaluated. Electronic medical records were reviewed to register the need for mitral surgery. The last echocardiogram available was also assessed to evaluate MR progression. 

Results

A total of 295 patients were included (235 MFS, 42 LDS, and 18 vEDS). The mean age at baseline was 39.0+-14.4 and 52.9% were female. MAD was present in 87 (37.0%) of MFS, 6 (14.3 %) of LDS and was not present in vEDS (p< 0.001). MVP was found in 105 (44.7%) of MFS, 6 (14.3%) of LDS and 0 in vEDS (p< 0.001).

In MFS, MAD was significantly associated with MVP (p= <0.001) (Table 1). Concretely, 73 (31.1%) of the MFS patients had the concurrence of MAD and MVP and 14 (6.0%) of patients had isolated MAD (Table 2). At baseline, significant MR was observed in 30 (12.8%) of the MFS and in 18 (24.7%) of patients with concurrent MAD and MVP. Interestingly, significant MR was absent in patients with isolated MAD (Figure 1). MVP (OR 16.85 CI 4.43 – 64.07) but not MAD (p = 0.607), was associated with significant MR in the multivariate analysis.

A second echocardiogram was available in 220 patients at > = 1 year (mean 4.1 +- 1.4 years). Overall, 25 (11.4%) presented significant progression of MR, 0 in the isolated MAD group, 13 (19.4%) in the MAD/MVP group and 6 (20.0%) of the isolated MVP (p = 0.007).

After a mean clinical follow-up of 7.5 +- 3.2yrs, 10 patients required mitral surgery (6 prostheses, 4 valvuloplasties).

After adjustment for the presence of MVP and time of follow-up, MAD was not associated with progression of MR (p= 0.529) but MVP was (OR 5.2 IC 1.70 - 15.93). Similarly, MVP (OR 5.6 CI 1.23 - 25.86)  but not MAD  (P= 0.096) was associated with the  need for mitral surgery ., 

Conclusions

The prevalence of MAD in syndromic HTAD is high, especially in Marfan syndrome, and absent in vEDS. In this retrospective observational study, the presence of MVP but not MAD was associated with mitral regurgitation evolution and the need for mitral surgery. Abstract Table 1  Abstract Figure 1

Clinical, laboratory, electrocardiogaphic and multimodality imaging outcome predictors in cardiac amyloidosis

Background

Cardiac affectation in amyloidosis is presented among 50% patients what implies worse prognostic. Early diagnosis and prognostic stratification is mandatory after the appearance of new therapies that could modify the course of the disease.

Purpose

The aim of the present study was to evaluate the main outcome predictors with multiparametric approach including clinical, laboratory, electrocardiographic and imaging parameters in patients with cardiac amyloidosis (CA).

Methods

We recruited patients (p) prospectively followed in our cardiomyopathy unit, for a mean period of 10 years (from 2010 to 2020) who were diagnosed with CA. Baseline clinical, laboratory and echocardiographic data were obtained. We collected cardiovascular risk factors and previous events. We performed a multimodality imaging study including echocardiogram (TTE) and cardiac magnetic resonance (CMR). TTE hallmarks of CA were recorded, as well as CMR parameters of cardiac function, myocardial mass and tissue characterization. Finally we evaluated the parameters related with mortality in the follow-up.

Results

A total of 98 p were included, with a mean age of 67.5±16.9 years old. Mean follow-up was 42,2±32 months. 22 p (24,4%) had light-chain amyloidosis (AL), 34 p (37,8%) wild type transthyretin amyloidosis (ATTRwt) and 34 p (37,8%) familiar transthyretin amyloidosis (ATTRm). 43p (47.78%) died in the follow-up. Factors related with mortality in the the follow-up where the age (HR 1.08, ppresence of hypertension (HR 2.81, p=0,002) diabetes (HR 3.12, p=0,001) and previous stroke (HR 2.69, p=0,01); NYHA class at diagnosis (HR 2.49, p<0.001), low voltage (HR 2.31, p=0,008) and pseudoinfarct pattern at ECG (HR 1.9, p=0,003); elevated BNP (HR 10.29, p<0.001) and creatinine (HR 1.42, p=0,02); septum (HR 1.09, p=0,001) and posterior wall (HR 1,14, p<0,001)thickness, left ventricular ejection fraction (HR 0.96, p=0,0031) global longitudinal strain (HR 1.18, p<0.001), ratio E/A (HR 2.29, p<0,001) and E/e' (HR 1.13, p=0,003) and left atrium size (HR 1,05, p=0,006) at echo; and the presence of left atrium fibrosis (HR 4.17, p>0,001) and extension of late gadolinium enhancement (HR 1,06, p=0,03) at CMR. When evaluated within a multivariate analysis in a Cox regression model, the independent variables associated with mortality were NYHA class at diagnosis (p=0.002) and amyloidosis type (p=0.002) ATTRm had a better prognosis than ATTRwt and AL (Log-rank p<0.001).

Conclusion

Mortality in cardiac amyloid patients is high. Clinical parameters like hypertension, diabetes, previous stroke and NYHA class at diagnosis; laboratory parameters like BNP and creatinine, main systolic and diastolic function at TTE, presence of auricular fibrosis and extension of late gadolinium enhancement at CRM are related with mortality in the follow-up. Among different types of CA, patients with ATTRm had a better prognosis, which may have therapeutic implications with the appearance of new therapies.

Funding Acknowledgement

Type of funding sources: None. Mortality

Circumferential wall shear stress predicts co-localized progressive dilation in bicuspid aortic valve patients

Background

Bicuspid aortic valve (BAV), a congenital heart defect, is associated with ascending aorta (AAo) dilation. Whether the high prevalence of dilation in BAV patients is related to alteration of aortic blood flow and thus in wall shear stress (WSS) [1,2], which have been associated with aortic wall degeneration [3], or intrinsic abnormalities of the aortic wall, such as altered aortic stiffness [4], has not been established. Recently, a technique for the semi-automatic quantification of progressive aortic dilation maps via image registration has been introduced [5].

Purpose

To test whether ascending aorta WSS predicts co-localized progressive dilation in BAV patients.

Methods

Forty BAV patients free from moderate and severe aortic valve regurgitation (regurgitant fraction <16%) and stenosis (maximum velocity at the aortic valve <3m/s), with no previous aortic or aortic valve surgery or replacement and included in a double-blind clinical trial (BICATOR, NCT02679261) were enrolled. All patients underwent a baseline 4D flow CMR study to assess aortic hemodynamics, followed by two contrast-enhanced computed tomography angiographies to quantify progressive dilation. WSS was computed at 64 pre-specified standardized ascending aortic regions, automatically obtained dividing the ascending aorta into 8 equidistant longitudinal sections which were further divided along the circumference into 8 equal regions (I = inner, L = left, O = outer and R = right) [2]. WSS was also projected into axial and circumferential directions, as previously described [1,2]. Progressive dilation was assessed in terms of growth rate (GR), i.e. increase in diameter divided by follow-up duration [mm/year], following a previously described methodology [5], at the same 64 pre-specified ascending aortic locations. A two-tailed p-value <0.05 was considered statistically significant.

Results

Demographic and clinical characteristics of the patients are shown in Table 1. WSS and growth rate maps are shown in Figure 1. Follow-up duration was 44.8±2.6 months. Growth rate (Figure 1A) was heterogeneously distributed, being highest (up to 0.26 mm/year) in the outer region of the mid AAo and in the inner region of the proximal-mid AAo. Circumferential WSS showed highest values in the outer region of the mid AAo (Figure 1C) while WSS (magnitude) and its axial component (Figure 1B and D) presented maximum values in the right region of the mid AAo. Maps of statistically significant association between GR and WSS values showed circumferential WSS to be correlated with GR in regions where progressive dilation was fastest, while WSS magnitude and its axial component resulted in limited associations with GR maps.

Conclusions

Circumferential wall shear stress predicts location-matched progressive dilation in bicuspid aortic valve patients.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): This study has received funding from the Instituto de Salud Carlos III (PI17/00381). Guala A. has received funding from Spanish Ministry of Science, Innovation and Universities (IJC2018-037349-I). Table 1. DemographicsFigure 1. GR and WSS maps and correlations

Clinical impact on treatment and prognosis of advanced cardiac imaging with echocardiography in the acute setting of a COVID-19 infection

Background and objectives

Despite myocardial injury being related to excess mortality in acute COVID-19 infection, its impact on imaging findings remains unclear. This study aimed to characterize transthoracic echocardiographic (TTE) findings in patients admitted with COVID-19 infections and its impact on management and prognosis.

Methods

A prospective observational cohort study was performed among 66 COVID-19 patients who were admitted to a tertiary center between March 1 and May 25, 2020 and underwent TTE. High-sensitivity troponin I (hs-cTnI) data, echocardiographic assessment of right and left ventricular (LV) functional parameters, strain, and myocardial work analysis were obtained.

Results

2025 patients were admitted with COVID-19 and in 200 a complete TTE study was performed. Due to poor image quality, only 66 studies were included in the final analysis. The median age was 62 years (IQR, 55–70) and 59.1% of patients were males. The most common comorbidity was hypertension (47%), followed by smoking history (30.3%), atrial fibrillation (9.1%), and chronic obstructive pulmonary disease (7.9%). More than half of the patients (39, 59%) were admitted to the ICU, and half of them (33, 50%) required invasive mechanical ventilation. TTE was mainly indicated because of concerns for systemic conditions (50%) and evaluation of hemodynamic assessment (30%). Thirty-six patients (54.5%) had an abnormal TTE result and 57% had elevated hs-cTnI levels. The most common cardiac abnormality was LV diastolic dysfunction in 33% of the patients, followed by right ventricular dysfunction (12%) and LV dysfunction (6%) (Figure 1). LV GLS was reduced in 48.5% of the cases. Myocardial work performance indices were all reduced in patients with an abnormal TTE (GWI 30%, GCW 30%, GWW 40%, and GWE 40%), although differences were not significant (P>0.2 for all parameters). Patients with an abnormal TTE were older and presented a higher cardiovascular risk profile. There were no significant differences in the levels of D-dimer, NTproBNP, and hs-cTnI between patients with and without diastolic dysfunction, RV, or LV dysfunction (P>0.3 for all parameters). Using Spearman rank correlation, there was an inverse relationship between hs-cTnI and LV strain and myocardial work analysis. TTE results impacted clinical management in 60 patients, mainly de-escalation of medical treatment (Figure 2). Abnormal TTE results did not impact in-hospital outcomes.

Conclusions

Severe echocardiographic abnormalities are uncommon in hospitalized patients with COVID-19 infections, presenting mostly with subclinical myocardial changes, such as diastolic dysfunction, reduced LV GLS, and myocardial work indices, both associated with high-sensitivity troponin I elevation. An echocardiographic study should be limited to rule out long-term ICU complications or to evaluate hemodynamic instability. Although TTE was a valuable tool for guiding management, it had no significant impact on prognosis.

Funding Acknowledgement

Type of funding sources: None. Figure 1. Findings on TTE studies.Figure 2. Changes in management.

Mitral annular disjunction in patients with syndromic hereditary aorthopaties

Background

Mitral annular disjunction (MAD) is a structural abnormality of the mitral annular fibrosus characterized by a separation between the atrial wall-mitral valve junction, and the left ventricular attachment (1). It has been associated with mitral valve prolapse (MVP) (2) but also, with arrhythmias and sudden cardiac death (SCD) (3). There is no evidence of its prevalence and clinical significance in patients with syndromic hereditary aortopathies.

Purpose

To evaluate the prevalence of MAD, PMV, and the combination of both in patients with syndromic hereditary thoracic aortic disease (HTAD) including Marfan (MFS), Loeys-Dietz (LDS) and vascular Ehlers-Danlos syndromes (vEDS), and its relationship with arrhythmias, SCD, mitral regurgitation (MR) severity and the need for mitral surgery at the follow-up.

Methods

Adult patients with syndromic HTAD seen at our specialized unit were retrospectively included. The presence of MAD, MVP, and significant MR at first echocardiogram were evaluated. Electronic medical records were reviewed to register the occurrence of arrhythmic events and the need of mitral surgery. Last echocardiogram available was also assessed to evaluate MR progression.

Results

A total of 295 patients were included (235 MFS, 42 LDS and 18 vEDS). Mean age at baseline was 39.0±14.4 and 52.9% were female. MAD was present in 87 (37.0%) of MFS, 6 (14.3%) of LDS and was not present in vEDS (p<0.001). MVP was found in 105 (44.7%) of MFS, 6 (14.3%) of LDS and 0 in vEDS (p<0.001).

In MFS, the presence of MAD was significantly associated with MVP (p≤0.001) (Table 1). However, 14 (6.0%) of patients had isolated MAD (Table 2). At baseline, significant MR was observed in 18 (24.7%) of patients with concurrent MAD and MVP and was not present in patients with isolated MAD (Table 2). MVP (OR 16.85 IC 4.43 – 64.07) but not MAD (p=0.607), was associated with significant MR in the multivariate analysis.

A second echocardiogram was available in 220 patients at ≥1 year (mean 4.1±1.4 years). Overall, 25 (11.4%) presented significant progression of MR, 0 in the isolated MAD group, 13 (19.4%) in the MAD/MVP group and 6 (20.0%) of the isolated MVP (p=0.007).

After a mean clinical follow-up of 7.5±3.2 years, 10 patients required mitral surgery (6 prosthesis, 4 valvuloplasty), 22 (9.4%) presented atrial fibrillation, flutter or supraventricular tachycardia (SVT), and 2 (0.9%) SCD.

After adjustment for the presence of MVP and time of follow-up, MAD was not associated with progression of MR (p=0.529) need for mitral surgery (p=0.096), atrial fibrillation-flutter or SVT (p=0.510) nor SCD. (p=0.997).

Conclusions

The prevalence of MAD in syndromic HTAD is high, especially in Marfan syndrome, and absent in vEDS. In this retrospective observational study, the presence of MAD in Marfan was not associated with mitral regurgitation evolution or arrhythmic events.

Funding Acknowledgement

Type of funding sources: None. Characteristics of MFS patientsPresence of significant MR by groups.

Evaluation of myocardial strain assessed by CMR tissue-tracking to predict adverse cardiovascular events in patients with cardiac amyloidosis

Background

Cardiac affectation in amyloidosis is presented among 50% patients what implies worse prognostic. Early diagnosis and prognostic stratification is mandatory after the appearance of new therapies that could modify the course of the disease.

Purpose

The aim of our study was to assess the prognostic value of cardiac magnetic resonance parameters, including Tissue deformation, in cardiac amyloidosis patients.

Methods

We recruited patients (p) prospectively followed in our cardiomyopathy unit, for a mean period of 10 years (from 2010 to 2020) who were diagnosed with CA. Baseline clinical, laboratory and echocardiographic data were obtained. Contrast-enhanced CMR was performed on a 1.5 T clinical scanner. Routine analysis was performed with a semi-automatic software for volumetric analysis. When late gadolinium enhancement was present, percentage of area of enhancement (LGE) was calculated.All strain parameters were measured off-line using dedicated software. Left ventricular circumferential strain (CS) measurements were obtained using mid-ventricular level short-axis cine views. Longitudinal strain (LS) derived from cine SSFP of 2-, 3-, and 4-chamber long axis views.Finally we evaluated the CMR parameters related with the combined event of mortality and heart failure in the follow-up.

Results

A total of 98 p were included, with a mean age of 67.5±16.9 years old. Mean follow-up was 42,2±32 months. 22 p (24,4%) had light-chain amyloidosis (AL), 34 p (37,8%) wild type transthyretin amyloidosis (ATTRwt) and 34 p (37,8%) familiar transthyretin amyloidosis (ATTRm). 59p (60,8%) died or present heart failure during the follow-up. Patients who died or present heart failure in the follow-uo had lower left ventricular ejection fraction (48,25±12,2% vs 56,13±11,03%, p=0,003), higher myocardial mass (156,05±54,8g vs 120,84±56,1g, p=0,007), higher LGE (8,6±6,8% vs 4,4±2%), worst GLS (−14,76±6,1% vs −18,67±6,2%) and worst GCS (−23,3±9,7% vs −30,04±9,1%). Both, GLS and GCS were independently associated with the combined event of dead or heart failure when evaluated within a multivariate analysis in a Cox regression model, but GCS was the stronger predictor of events in the follow-up over other CMR parameters like LGE an myocardial mass (p<0,001). Tertile distribution for GCS identified subgroups with different adverse events, particularly for the lowest-risk tertile: GCS <−34%, who had a combinated event in 13,6% of cases, significantly lower than patients in the mid-risk tertile (41,5%) and highest-risk tertile (53,8%) (Log-rank p=0,02)

Conclusion

Mortality and appearance of heart failure in cardiac amyloid patients is high. The assessment of myocardial strain parameters by CMR tissue-tracking in this population is useful to predict adverse outcomes in the follow-up. Particularly, GCS, stratify patients in subgroups with different risk of events, with added value to classical CMR parameters.

Funding Acknowledgement

Type of funding sources: None. Death & Heart Failure by GCS

Do morphological, haemodynamic and biomechanical parameters relate to aortic growth rate in chronic type B aortic dissection? A 4D flow CMR study

Background

Aortic dissection (AD) is the most devastating complication of thoracic aortic disease (1). In the chronic phase, yearly clinical and imaging follow-up of the maximum aortic diameter is recommended, since indication for thoracic endovascular aortic repair or surgery is suggested by guidelines in case of thoracic aortic enlargement or false lumen (FL) aneurysms (2). Most of the reported parameters related adverse events in chronic AD are focused on morphological variables (3) and not on the haemodynamics and biomechanics of the FL.

Purpose

To evaluate the relationship between aortic growth rate and anatomical variables, flow patterns and aortic stiffness in patients with chronic type B AD.

Methods

Forty-one patients with chronic type B aortic dissection, no connective tissue disorders and with an imaging follow-up including two computed tomography angiograms (CTA) acquired at least 3 years apart underwent contrast-enhanced 4D-flow CMR and MR angiography (MRA). The FL volume was segmented from MRA, and velocity data inside the 3D volume of the FL was extracted from 4D-flow CMR and used for parameter quantification. Retrograde systolic and diastolic flow, wall shear stress (WSS) and in-plane rotational flow (IRF) were calculated at 8 equidistant planes in the distal descending aorta (DAo), from the pulmonary bifurcation to the diaphragmatic level, and averaged values were used [4]. Aortic stiffness in the FL was assessed in terms of pulse wave velocity (PWV), which was calculated from the third supraortic trunk to the diaphragmatic level on 4D-flow CMR [5]. The percentage of thrombus in the FL was calculated as the ratio of thrombus and FL volumes on MRA. Dominant entry tear area was quantified on the baseline CTA (Figure 1). Aortic growth rate (GR) was defined as the difference between final and baseline aortic diameters as measured on CTA divided by follow-up duration.

Results

Anatomical, haemodynamic and biomechanical parameters are shown in Table. Twenty-five patients have repaired type A AD with residual entry tear and 16 have type B AD. Mean follow-up duration was of 4.9±2.7 years. In bivariate analysis, WSS, IRF and PWV were positively related to GR, whereas dominant entry tear area and percentage of thrombus in the FL showed a positive tendency with GR (Table) (Figure). In multivariate analysis IRF, PWV, dominant entry tear area and thrombus in the FL were positively and independently associated with GR (Table). Retrograde systolic and diastolic flow were not related to GR while WSS tended to statistical significance.

Conclusions

In-plane rotational flow, regional aortic stiffness, dominant entry tear area and percentage of thrombus in the false lumen are positively and independently related to aortic growth rate in patients with chronic type B aortic dissection. Further prospective studies are needed to confirm if the assessment of these parameters may help to identify patients at higher risk of adverse clinical events.

Funding Acknowledgement

Type of funding sources: None. Table 1Figure 1

Accurate and reproducible aortic growth rate mapping via registration of serial contrast-enhanced computed tomography angiograms

Introduction

Accurate assessment of aortic diameters and growth rates is key for clinical management of patients with aortic aneurysms [1]. Manual assessment on multiplanar reformatted views of computed tomography angiograms (CTA) is recommended [1], although its reproducibility in the assessment of growth rates has not been reported [2]. Image registration has been proposed to provide 3D maps of aortic diameters and growth [3], but its accuracy and reproducibility have not been established.

Purpose

To quantify accuracy and inter-observer reproducibility of aortic root and thoracic aorta diameters and growth rate by registration of serial CTAs compared to current standard.

Methods

Forty non-operated patients with ≥2 contrast-enhanced ECG-gated CTA acquired at least 6 months apart were included. Aortic diameters and growth rates were measured in the aortic root and thoracic aorta by two independent observers, both with the current standard and with the registration-based technique. To perform registration-based assessment, each observer semi-automatically segmented the aorta at baseline and located typical anatomical landmarks (Fig. 1A). Then, deformable image registration was used to map baseline and follow-up CT scans and deformation was applied to the baseline aortic surface points to obtain their location at follow-up (Fig. 1B). Finally, aortic root diameters and growth rate and 3D maps of thoracic aortic diameters and growth rate were automatically obtained (Fig. 1C). Agreement between techniques and their inter-observer reproducibility were calculated.

Results

Follow-up duration was 3.3±1.5 years (range 0.52–6.2). Compared with manual assessment, registration-based aortic diameters presented low bias and excellent agreement in the aortic root (0.42 mm, ICC=0.99) and the thoracic aorta (0.55 mm, ICC=0.99), and similar inter-observer reproducibility (ICC=0.99 for both). Compared with manual assessment, registration-based growth rates presented low bias and good agreement in the aortic root (0.12 mm/y, ICC=0.84) and the thoracic aorta (0.03 mm/y, ICC=0.77) (Fig. 2A), and much higher inter-observer reproducibility (ICC=0.96 vs 0.68 in the aortic root, ICC=0.96 vs 0.80 in the thoracic aorta) (Fig. 2B and C). Registration-based aortic growth rates reproducibility at 6 months follow-up was comparable to that obtained by manual assessment at 2.7 years (LoA = [−0.01, 0.33] and LoA = [−0.13, 0.21], respectively). Aortic diameters and growth rate 3D maps were highly reproducible (ICC>0.9) in the whole thoracic aorta.

Conclusions

Progressive aortic dilation assessment via registration of CTAs is accurate and more reproducible than the current standard even over follow-ups as short as 6 months, and further provides robust 3D mapping of aortic diameters and growth rates. Its application may provide new insights in aneurysms pathophysiology and improve the clinical management of these patients.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): This study has received funding from the Instituto de Salud Carlos III (PI17/00381). Guala A. has received funding from Spanish Ministry of Science, Innovation and Universities (IJC2018-037349-I). Figure 1. Methodology.Figure 2. Growth rate comparison.

Bicuspid aortic valve fusion length correlates with maximum aortic diameter and heamodynamic abnormalities: a 4D flow CMR study

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Guala A. received funding from the Spanish Ministry of Science, Innovation and Universities.

Background

Bicuspid aortic valve (BAV), a congenital heart defect, is associated with ascending aorta dilation, possibly via alteration of aortic blood flow [1]. In BAV abnormal flow condition have been associated with aortic extracellular matrix dysregulation and elastic fiber degeneration [2]. Current morphological classification of BAV patients with aortic valve with a single fusion between two adjacent leaflets does not allow for risk stratification.

Purpose

This research work tested whether the extent of fusion between leaflets is related to AAo diameter and flow alterations.

Methods

Ninety BAV patients free from moderate and severe aortic valve disease and with no previous aortic or aortic valve surgery or replacement were prospectively enrolled. A comprehensive magnetic resonance protocol comprised a stack of double-oblique 2D balanced steady-state free-precession (bSSFP) cine CMR of the aortic valve, which was used to measure the length of the fusion between leaflets, a cine CMR at the level of the pulmonary bifurcation to assess aortic diameter and 4D flow MRI sequence to assess flow characteristics and regional stiffness [3]. Jet angle and flow radial displacement, quantifying the extent of flow eccentricity, and systolic flow reversal ratio (SFRR), assessing the relative amount of backward flow during systole, were computed at 8 equidistant planes in the ascending aorta and 4 equidistant planes in the aortic arch [4]. A two-tailed p-value < 0.05 was considered statistically significant.

Results

The length of leaflet fusion varied widely (median 7.7 mm, inter-quartile range [5.5; 10.2]), Table 1). In bivariate analysis, fusion length was also associated to ascending aortic diameter (R = 0.391, p < 0.001), age (R = 0.313, p = 0.005) and body surface area (R = 0.396, p < 0.001). It was also positively related to flow abnormalities: like displacement in the proximal and distal ascending aorta, jet angle in the mid ascending aorta, and SFRR in the ascending aorta and the aortic arch (see Figure 1). The association between fusion length and ascending aorta diameter persisted in multivariate analysis after correction for age (p = 0.006).

Conclusions

Bicuspid aortic valve fusion extent varies greatly and it is associated with aortic diameter, possibly through flow alterations. Prospective longitudinal studies are needed to establish whether fusion length may allow for risk stratification in bicuspid aortic valve patients.

Aortic rotational flow patterns and stiffness by 4D flow CMR in patients with Loeys-Dietz syndrome compared to healthy volunteers and patients with Marfan syndrome

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): La Marató de TV3, Instituto de Salud Carlos III through the project and Spanish Ministry of Science, Innovation and Universities.

BACKGROUND

Loeys-Dietz (LDS) and Marfan (MFS) syndromes are rare genetic connective tissue disorders associated with progressive aortic dilation, however, aortic dissections have been observed at lower aortic root diameters in LDS than in MFS. Recent CMR studies in MFS patients reported increased aortic stiffness (1–3) and altered rotational flow (4), but research on aortic flow dynamics and biomechanics in LDS is lacking.

PURPOSE

The aim of this study was to assess rotational aortic flow and aortic stiffness in LDS compared to healthy volunteers (HV) and MFS patients, using 4Dflow CMR.

METHODS

Twenty-one LDS and 44 MFS patients, without previous aortic dissection or surgery, and 43 HV underwent a non-contrast-enhanced 4D flow CMR. Aortic stiffness was quantified at the AAo and DAo using pulse wave velocity (PWV). In-plane rotational flow (IRF), systolic flow reversal ratio (SFRR) (5) and local aortic diameters were obtained at 20 equidistant planes from the ascending (AAo) to the proximal descending aorta (DAo).

RESULTS

LDS patients had lower IRF at the distal AAo and proximal DAo compared to HV (p = 0.053 and 0.004, respectively), once adjusted for age, stroke volume and local aortic diameter; but no differences were found with respect to MFS (Figure). Although SFRR at the proximal DAo was increased in LDS patients compared to both HV (p = 0.037) and MFS populations (p = 0.015), once adjusted for age and aortic diameter, the difference in magnitude was small (Figure). On the other hand, AAo and DAo PWV revealed stiffer aortas in LDS patients compared to HV but no differences versus MFS patients (Table).

CONCLUSIONS

Patients with Loeys-Dietz syndrome showed decreased in-plane rotational flow and abnormally-high regional aortic stiffness compared to healthy controls, and similar hemodynamics and aortic stiffness with respect to patients with Marfan syndrome.

Long term outcomes in left ventricular noncompaction

Funding Acknowledgements

Type of funding sources: None.

Background

Left ventricular noncompaction (LVNC) is a heterogeneous entity with a wide phenotypic expression. Risk factors have not been well established and prognostic stratification remains challenging.

Objectives

Describe long term outcomes of LVNC patients and determine predictors of cardiovascular events. 

Methods

 

Prospective multicentric study of consecutive patients fulfilling imaging diangostic criteria for LVNC (Jenni echo criteria and Petersen CMR criteria). Demographic, ECG, imaging and genetic variables were collected. End points were heart failure (HF), ventricular arrhythmias (VA), systemic embolisms (SE) and all-cause death. Major adverse cardiovascular events (MACE) was the combination of the four previous end points.

Results

585 patients from 12 referral centres were included from 2000 to 2018. Age at diagnosis was 45 ± 20 years, 334 (57%) were male, baseline LVEF was 48 ± 17% and 18% presented late gadolinium enhancement (LGE). During a median follow-up of 5.1 years (IQR 2.3-8.1), 110 (19%) patients presented HF, 87 (15%) VA, 18 (3%) SE and 34 (6%) died. MACE occurred in 223 (38%) patients.

LVEF was independently associated with HF, VA, SE and MACE: HR were 1.08, 1.02, 1.04 and 1.02 respectively (all p < 0.05). LGE was more frequent in patients with reduced LVEF (39 Vs 53%, p < 0.001) and was associated with higher HF and VA risk in patients with LVEF > 35% (HR 2.69 and 2.48 respectively, p < 0.05) (Figure 1). Patients with a normal ECG, LVEF≥50%, no LGE and no family aggregation presented no MACE (0%) at long term follow-up.

Among patients who underwent genetic testing (354, 61%), TTN variants and complex genotype (more than one variant) presented lower LVEF and higher HF risk. ACTC1 variants were associated with VA.

Conclusions

LVNC carries a high long term risk of heart faliure and ventricular arrhythmias. LVEF is the most important predictor and myocardial fibrosis is associated with increased risk in patients without severe systolic dysfunction. Genotype is a modifier of outcomes. These factors might be used to risk stratify LVNC patients.

Abstract Figure. Kaplan Meier survival curves

Aortic root longitudinal strain by speckle-tracking echocardiography predicts progressive aortic root dilation in Marfan syndrome patients

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Spanish Ministry of Science, Innovation and Universities; Instituto de Salud Carlos III

Introduction

In Marfan syndrome (MFS) patients reduced longitudinal strain of the ascending aorta (AAo) as measured by applying feature-tracking on cine cardiac magnetic resonance (CMR) images predicts aortic root dilation and aortic events during the follow-up. Speckle-tracking is well established for cardiac deformation assessment but proximal aorta applications are challenging due to limited wall thickness and substantial cardiac motion. Moreover, echocardiography is widely used in the clinical assessment aortic diseases.

Purpose

We aimed to test a speckle-tracking tool for root longitudinal strain analysis in terms of comparison with CMR-derived AAo longitudinal strain and reproducibility and as predictor of dilation in MFS patients.

Methods

Thirty-five MFS patients diagnosed by original GHENT criteria, with maximum aortic root diameter of 45 mm and free from previous aortic dissection or cardiac/aortic surgery and non-severe aortic regurgitation were consecutive enrolled and followed-up. CMR and echocardiography were performed less than 2 months apart. Baseline and final aortic root diameter were measured on CMR images. To quantify aortic root cyclic elongation by echocardiography, two regions of interests were manually created covering both walls in a parasternal long-axis view and tracked along the cardiac cycle (Figure 1). Longitudinal strain was computed as the average of maximum increase in relative distance of several sub-regions covering both walls. CMR-derived AAo longitudinal strain was available in 29 patients. Intra-observer reproducibility was tested in 15 patients via intraclass correlation coefficient (ICC) for single-rater absolute agreement.

Results

Aortic root longitudinal strain by echocardiography was mildly related to CMR-derived AAo longitudinal strain (R = 0.27) and was larger compared to CMR-derived values (16.2 ± 6.0 vs 11.3 ± 4.3). Reproducibility was high, with ICC of 0.811, R = 0.802, p < 0.001. After a mean follow up of 76 ± 13 months, aortic root diameter grew in 20 patients with a rate of 0.29± 0.24 mm/year. Overall mean growth-rate was 0.87 ± 0.33 mm/year. In multivariable analysis corrected for age and baseline aortic root diameter, baseline longitudinal strain by echocardiography was independently and inversely related to progressive dilation (p = 0.033).

Conclusions

The measurement of aortic root longitudinal strain by speckle-tracking echocardiography is feasible. Aortic root longitudinal strain is an independent predictor of progressive dilation in MFS patients. This may permit the improvement of risk-stratification in aortic diseases in large scale studies.

Abstract Figure 1

Leaflets fusion length in bicuspid aortic valve is related to ascending and aortic root dilation and ascending aorta wall shear stress

Funding Acknowledgements

Type of funding sources: Public Institution(s). Main funding source(s): Spanish Ministry of Science, Innovation and Universities, Instituto de Salud Carlos III

Background

Bicuspid aortic valve (BAV) is the most common congenital heart defect, consisting in the fusion of two aortic valve leaflets. Altered flow patterns have been related to aortic wall degeneration in BAV patients and may be responsible for the high prevalence of aortic disease in these patients. A number of studies on excised BAV or using advanced imaging modalities reported a wide variability of fusion extent between leaflet, but no previous study assessed whether leaflet fusion length may be used to stratify BAV patients.

Purpose

We aimed to test whether leaflet fusion extent can be quantified by cardiac magnetic resonance imaging (CMR) and whether it is related to aortic dilation and flow abnormalities in non-dysfunctional BAV.

Methods

One hundred and twenty BAV adults with no previous aortic or aortic valve surgery or significant valvular disease were consecutively enrolled. Patients with two sinuses of Valsalva (true BAV) or fusion of the left and non-coronary cusps, both being rare forms of BAV, were excluded. Twenty-eight healthy volunteers were also included for comparison. A 4D flow CMR sequence was acquired and circumferential wall shear stress and pulse wave velocity were assessed in the ascending aorta. A stack of double-oblique cine images of the aortic valve were used to quantify the length of the fusion between leaflets.

Results

The length of the fusion between leaflets was effectively measured in 112/120 patients (93%). Reproducibility was good (ICC = 0.826). Fusion length varied greatly (range 2.3 – 15.4 mm, 7.8 ± 3.2 mm, tertiles cut-off points were 6 and 9.3 mm). After correction for age, BSA, stroke volume and BAV fusion morphotype, fusion length was independently associated with diameter at the sinus of Valsalva (p = 0.002). Moreover, once corrected for age, stroke volume and ascending aorta pulse wave velocity, fusion length was positively related to ascending aorta diameter (p = 0.028). The comparison of maps of circumferential peak-systolic WSS in healthy volunteers (left) and BAV patients pertaining to the three leaflet fusion length tertiles is shown in Figure 1. Circumferential WSS progressively increase with larger fusion length. This trend was statistically significant (p < 0.05) in the right and outer regions of the proximal and mid ascending aorta.

Conclusions

Bicuspid aortic leaflet fusion length varies considerably and it is independently associated with ascending aorta and aortic root dilation, possibly through flow alterations.

Abstract Figure 1

Regional curvature in thoracic aortic aneurysms of different aetiologies and its relationship with established risk factors

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Spanish Ministry of Science, Innovation and Universities ; Instituto de Salud Carlos III

Introduction

The aorta is a 3D hollow, curvilinear elastic structure whose diseases have life-threatening consequences. Despite much effort has been paid to study aortic diameter, diameter is a poor predictor of events. Conversely, much less is known about aortic curvature, its distribution in the thoracic aorta and the potential impact of risk factors in aneurysms associated with different conditions. Currently, 4D flow magnetic resonance imaging (4D flow CMR) allows to obtain 3D geometry, 4D flow data and regional aortic stiffness.

Purpose

We aim to study regional aortic curvature in thoracic aorta aneurysms of different aetiologies and define its relationship with established risk factors.

Methods

One-hundred twenty patients (40 for each group, selected out of prospective cohorts of 156 bicuspid aortic valve – BAV-, 77 Marfan –MFS- and 67 patients with a degenerative aneurysm – TAVdeg-) were matched for age, sex and BSA via propensity score with 40 healthy volunteers (HV). The thoracic aorta was semi-automatically segmented from angiograms and the centreline was computed. Local curvature was assessed at 20 planes covering the thoracic aorta from the sinotubular junction to the proximal descending aorta (DAo) at the level of the pulmonary artery bifurcation. Local curvature was normalized by subject mean thoracic aorta curvature. Length was measured as centreline length. Aortic stiffness was measured in the DAo by pulse wave velocity (PWV). Aneurysm was defined by z-score ≥ 2 using diameters measured by double-oblique cine CMR.

Results

Matching was successful in all groups with the exception of a residual age difference between HV and TAVdeg. Curvature in HV showed a fairly smooth transition between the straighter ascending aorta (AAo) and DAo to a more curved aortic arch, with a peak in the mid aortic arch (Figure 1A).  Conversely, all patients’ groups presented a peak in curvature in the proximal DAo and a decreased local curvature in the aortic arch and mid DAo close to the level of the pulmonary artery. BAV and TAVdeg patients showed also increased curvature in the mid AAo, were dilation is prevalent. Conversely, in the same area MFS showed a reduced curvature and limited prevalence of aneurysm. In the overall population, age, AAo and root diameters, mean blood pressure, DAo PWV and aortic length, all established risk factors for aortic events, were inversely related to curvature in the distal AAo and aortic arch (Figure 1B).

Conclusions

Aneurysms related to different aetiologies show similar abnormalities in aortic curvature, with limited curvature in the aortic arch and a peak soon after the third supra-aortic vessel. Age, aortic diameter, length, stiffness and blood pressure, all known risk factors, are all related to reduced curvature in the distal ascending aorta and aortic arch.

Abstract Figure.

Semi-automatic quantification of aortic root progressive dilation by automatic co-registration of computed tomography angiograms: a preliminary comparison with manual assessment in Marfan patients

Funding Acknowledgements

Type of funding sources: Public Institution(s). Main funding source(s): Spanish Ministry of Science, Innovation and Universities Instituto de Salud Carlos III

Background. Dilation of the aortic root is a key feature of Marfan syndrome and it is related to the occurrence of aortic events and death. On top of maximum diameter, rapid annual growth rate is suggested by guidelines for indication of aortic root replacement. Current gold-standard for aortic root diameter assessment is manual quantification on multiplanar reformatted 3D computed tomography (CT) or magnetic resonance angiogram. However, inter- and intra-observer reproducibility are limited and different measurement methods, i.e. cusp-to-cusp and cusp-to-commissure, may be used in different clinical centres, leading to difficulties in the clinical assessment of progressive dilation.

Purpose. We aimed to test whether aortic root growth rate during follow-up can be reliably quantified by semi-automatic co-registration of two CT angiograms.

Methods. Seven Marfan syndrome patients, free from previous aortic surgery, with a total of 11 pairs of CT were identified. Manual assessment of six aortic root diameters (right-non coronary -RN- , right-left -RL- and left-non coronary -LN- cusp-to-cusp and R, L and N cusp-to-commissure) was obtained from all CTs by an experienced researcher blind to semi-automatic results. The thoracic aorta and the outflow tract were semi-automatically segmented in the baseline CT and commissure and cusps were manually located. A 10 mm-thick region of interest containing the aortic wall was automatically generated from segmentation boundary. Co-registration was obtained with three, fully-automatic steps. Firstly, baseline and follow-up CT scans were aligned by means of a rigid registration. Then, scans were co-registered with multi-resolution affine followed by b-spline non-rigid registrations based on mutual information metric. The transformation pertaining to the location of baseline commissure and cusps points was used to locate the same points in the follow-up scan (Fig. 1 top).

Results. Follow-up duration was 35 ± 22 (range 12-70.3) months. Automatic quantification of diameter growth during the follow-up was obtained in 62 out of 66 (94%) diameter comparisons. High Pearson correlation coefficients (R) and ICC were found between manual and semi-automatic assessment of growth rate, both for cusp-to-cusp and cusp-to-commissure diameters: R = 0.727 and ICC = 0.678 for RN; R = 0.822 and ICC = 0.602 for RL; R = 0.648 and ICC = 0.668 for LN; R = 0.726 and ICC = 0.711 for R; R = 0.911 and ICC = 0.895 for L and R = 0.553 and ICC = 0.482 for N. Scatter and Bland-Altman plots for all growth rates (Fig. 1) confirmed very good correlation (R = 0.810) but a slight tendency (R=-0.270) for underestimation at high growth rate.  No correlation was found between follow-up duration and difference between techniques (R = 0.06).

Conclusions. Semi-automatic quantification of aortic root growth rate by co-registration of pairs of CT angiograms is feasible for follow-up as short as one year. Larger studies are needed to confirm these preliminary data.

Abstract Figure. CT measurements. Automatic vs manual.

NMR and LC-MS-Based Metabolomics to Study Osmotic Stress in Lignan-Deficient Flax

Lignans, phenolic plant secondary metabolites, are derived from the phenylpropanoid biosynthetic pathway. Although, being investigated for their health benefits in terms of antioxidant, antitumor, anti-inflammatory and antiviral properties, the role of these molecules in plants remains incompletely elucidated; a potential role in stress response mechanisms has been, however, proposed. In this study, a non-targeted metabolomic analysis of the roots, stems, and leaves of wild-type and PLR1-RNAi transgenic flax, devoid of (+) secoisolariciresinol diglucoside ((+) SDG)-the main flaxseed lignan, was performed using 1H-NMR and LC-MS, in order to obtain further insight into the involvement of lignan in the response of plant to osmotic stress. Results showed that wild-type and lignan-deficient flax plants have different metabolic responses after being exposed to osmotic stress conditions, but they both showed the capacity to induce an adaptive response to osmotic stress. These findings suggest the indirect involvement of lignans in osmotic stress response.

Are aortic root and ascending aorta echocardiographic diameters by adult vs paediatric guidelines recommendations interchangeable?

Background

Both aortic root size and ascending aorta are clinical parameters with significant therapeutic implications which can be easily assessed by transthoracic echocardiography (TTE). However, measurement values may vary according to cardiac cycle and the edge convention used.

Purpose

This study aimed to compare the aortic diameter values measured using the lastest recommendations of two different guidelines, adults and children, to determine the influence of these methods on echocardiographic measurements.

Methods

Two hundred and fifty adult patients (56% male, 63±15 years of age) and 67 children (65% male, 10.04±4.5 years of age) in whom TTE was clinically indicated were included. Aortic diameters were measured twice at 2 levels (sinuses of Valsalva and ascending aorta): leading edge to leading edge during diastole, (L-L in D) following the 2015 American Society of Echocardiography (ASE) adults guidelines and inner edge to inner edge during systole (I-I in S) following the 2010 ASE paediatric guidelines.

Results

Mean aortic diameters obtained by L-L in D and I-I in S are shown in Table 1. Correlation coefficient was 0.990 (CI95% 0.988–0.992) for sinuses of Valsalva measurements and 0.991 (CI95% 0.989–0.993) for ascending aorta in adult patients and 0.983 (CI95% 0.975–0.973) and 0.970 (CI95% 0.956–0.952) in childrens respectively. When both populations were analysed together, concordance correlation coefficients were 0.991 (CI95% 0.989–0.993) and 0.970 (CI95% 0.991–0.994), respectively. Bland- Altman analysis for each level measured (A: aortic root; B: ascending aorta) in the total cohort of 317 patients is shown in Figure 1. Mean aortic diameters and differences in the whole group are shown in Table 1.

Conclusions

Measurement of aortic root and ascending aorta showed a significantly larger diameters by L-L in D than by I-I in S. However, these differences had subclinical significance and management implications. These similar diameter values may be used indifferently but systematically during follow-up. Systolic diameter expansion has a similar value to that of anterior aortic wall thickness; however, it is more vulnerable to changes in haemodynamic conditions.

Figure 1

Funding Acknowledgement

Type of funding source: Public Institution(s). Main funding source(s): Vall d'Hebron Research Institute

Aortic stiffness and hemodynamics in Loeys-Dietz syndrome by 4Dflow CMR: a comparison with healthy volunteers and patients with Marfan syndrome

Background

Connective tissue disorders, such as Loeys-Dietz (LDS) and Marfan (MFS) syndromes, are rare genetic diseases associated with progressive aortic dilation. Aortic dissections have been observed at lower aortic root diameters in LDS than in MFS, and research on aortic flow dynamics and biomechanics in LDS is lacking.

Purpose

To evaluate rotational aortic flow and aortic stiffness in LDS compared to healthy volunteers (HV) and MFS patients, using 4Dflow CMR.

Methods

Twenty-one LDS and 44 MFS patients, without previous aortic dissection or surgery, and 44 HV underwent a non-contrast-enhanced 4D flow CMR. In-plane rotational flow (IRF), systolic flow reversal ratio (SFRR) and local aortic diameters were obtained at 20 equidistant planes from the ascending (AAo) to the proximal descending aorta (DAo). Aortic stiffness was quantified at the AAo and DAo using pulse wave velocity (PWV).

Results

LDS patients had lower IRF at the distal AAo and proximal DAo compared to HV (p=0.053 and 0.004, respectively), once adjusted for age, stroke volume and local aortic diameter; but no differences were found with respect to MFS (Figure). Although SFRR at the proximal DAo was increased in LDS patients compared to both HV (p=0.037) and MFS populations (p=0.015), once adjusted for age and aortic diameter, the difference in magnitude was small (Figure). On the other hand, AAo and DAo PWV revealed stiffer aortas in LDS patients compared to HV but no differences versus MFS patients (Table).

Conclusions

LDS patients showed decreased in-plane rotational flow and abnormally-high regional aortic stiffness compared to healthy controls, and similar hemodynamics and aortic stiffness with respect to MFS patients

Funding Acknowledgement

Type of funding source: Public Institution(s). Main funding source(s): Instituto de Salud Carlos III, La Maratό TV3

The length of the fusion between leaflets in bicuspid aortic valve is independently related to ascending aorta dilation and flow dynamics alterations assessed by 4D-flow CMR

Background

Aortic dilation in bicuspid aortic valve (BAV) patients has been related to altered flow patterns, which contribute to aortic wall degeneration. However, preventive aortic replacement is currently based on a diameter threshold. Several studies on excised BAV reported wide variability of fusion extent.

Purpose

To unveil whether leaflet fusion extent can be quantified by CMR and is related to aortic dilation and flow abnormalities in non-dysfunctional BAV.

Methods

One hundred and twenty adults with non-dysfunctional BAV and no previous aortic or aortic valve surgery and 28 healthy volunteers underwent double-oblique cine and 4D flow CMR. BAV patients with two sinuses of Valsalva or left and non-coronary cusps fusion were excluded. Peak systolic circumferential wall shear stress (WSSc) and pulse wave velocity (PWV) in the ascending aorta (AAo) were assessed by 4D flow CMR. Fusion length between leaflets was measured using a stack of double-oblique cine CMR images of the aortic valve.

Results

The length of the fusion was effectively measured in 112/120 (93%) patients with good reproducibility (ICC = 0.826) and showed great variability (range 2.3–15.4 mm, 7.8±3.2 mm and tertiles cut-off points 6 and 9.3 mm). In multivariate analysis adjusted for clinical and demographic characteristics and PWV, fusion length was independently associated with the diameter at the sinus of Valsalva (p=0.002) and the AAo (p=0.02) (Table). WSSc progressively increased with larger fusion length (Figure), with statistical significance (p<0.05) in the right and outer regions of the proximal and mid AAo.

Conclusions

Bicuspid aortic leaflet fusion length varies considerably, and it is independently associated with AAo and aortic root dilation, possibly through flow alterations.

Figure 1. Maps of circumferential WSS

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): This study has been partially funded by Instituto Carlos III, Spanish Ministry of Science and Innovation (PI17/00381). Guala A. has received funding from the Spanish Ministry of Science, Innovation and Universities (IJC2018-037349-I).

P372 Aortic stiffness in Loeys-Dietz syndrome: a comparison with Marfan syndrome patients and healthy volunteers

Funding Acknowledgements

ISCIII PI14/0106 and PI17/00381, La Marató de TV3 (20151330), Eur FP7/People 267128 and CIBERCV

BACKGROUND

Genetic syndromic aortic diseases are rare, with Marfan syndrome (MFS) being the most common. However, less is known of Loeys-Dietz syndrome (LDS) which has much lower prevalence and presumed worse prognosis. Increased aortic stiffness in MFS has been previously described but no studies have evaluated aortic biomechanics in LDS. Pulse wave velocity (PWV) is the gold standard measure for arterial stiffness and can be quantified by 4D flow MRI. We aim to evaluate regional aortic PWV by 4D flow MRI in LDS compared to MFS and healthy volunteers.

METHODS

Sixteen LDS patients with a pathogenic mutation, 76 MFS and 49 healthy volunteers were prospectively and consecutively included. No patient had previous aortic dissection or surgery. All underwent a 4D flow MRI study in a 1.5 T clinical scanner. Ascending (AAo) and descending (DAo) aorta PWV were computed using wavelet analysis of the systolic upslope for transit time calculation (Figure). Statistical comparison was made with non-parametric analysis to account for the non-normality of data and multivariate analysis was evaluated separately for AAo and DAo PWV.

RESULTS

Ascending and descending aortic PWV revealed stiffer aortas in LDS patients than in healthy volunteers, even after adjustment for diameter of sinus of Valsalva (SoV) and sex. Conversely, no differences in aortic stiffness were found between LDS and MFS patients (Table).

CONCLUSIONS

Abnormally high regional aortic stiffness was observed in LDS patients when compared with controls. The severity of increased regional aortic stiffness was found similar to the one affecting MFS patients.

Table Controls (N = 49) LDS (N = 16) MFS (N = 76) LDS vs. HV LDS vs. MFN Parameter Unadjusted p-value Adjusted p-value Unadjusted p-value Adjusted p-value Age [years] 39 ± 12 39 ± 16 36 ± 12 0.903 0.599 Men 32 (65%) 6 (37%) 34 (45%) 0.079 0.782 Weight [kg] 72 ± 11 69 ± 13 74 ± 16 0.288 0.194 Height [cm] 172 ± 8 172 ±12 181 ± 11 0.834 0.008 Systolic BP [mmHg] 126 ± 18 125 ± 14 127 ± 17 0.957 0.523 Diastolic BP [mmHg] 70 ± 11 77 ± 6 75 ± 12 0.011 0.318 SoV diameter [mm] 30.6 ± 3.9 35.4 ± 4.6 38.1 ± 5.9 0.001 0.060 AAo diameter [mm] 27.7 ± 3.8 29,0 ± 5.0 29.7 ± 5.4 0.458 0.579 DAo diameter [mm] 20.0 ± 2.0 21.3 ± 3.6 22.9 ± 3.8 0.546 0.124 AAo PWV [m/s] 5.2 ± 1.9 7.6 ± 2.4 7.3 ± 2.8 0.001 0.050* 0.534 NS DAo PWV [m/s] 7.1 ± 2.2 9.4 ± 2.6 10.7 ± 4.6 0.003 0.025** 0.493 NS

Abstract P372 Figure

Factors influencing the relationship between fluoride in drinking water and dental fluorosis: a ten-year systematic review and meta-analysis

The relationship between naturally fluoridated groundwater and dental fluorosis has received large attention from researchers around the world. Despite recognition that several factors influence this relationship, there is a lack of systematic studies analyzing the heterogeneity of these results. To fill such a gap, this study performs a systematic review and meta-analysis to understand which factors influence this relationship and how. Selected studies were sampled between 2007 and 2017 from Web of Science, PubMed, Google Scholar and Scopus using keywords and Boolean operators. Results of the systematic review show that dental fluorosis affects individuals of all ages, with the highest prevalence below 11, while the impact of other factors (gender, environmental conditions, diet and dental caries) was inconclusive. Meta-regression analysis, based on information collected through systematic review, indicates that both fluoride in drinking water and temperature influence dental fluorosis significantly and that these studies might be affected by publication bias. Findings show that fluoride negatively affects people's health in less developed countries. The conclusions discuss policy tools and technological innovations that could reduce fluoride levels below that of the World Health Organization (WHO) (<1.5 mg/L).

A Molecular Framework for the Control of Adventitious Rooting by TIR1/AFB2-Aux/IAA-Dependent Auxin Signaling in Arabidopsis

In Arabidopsis thaliana, canonical auxin-dependent gene regulation is mediated by 23 transcription factors from the AUXIN RESPONSE FACTOR (ARF) family that interact with auxin/indole acetic acid repressors (Aux/IAAs), which themselves form co-receptor complexes with one of six TRANSPORT INHIBITOR1/AUXIN-SIGNALLING F-BOX (TIR1/AFB) proteins. Different combinations of co-receptors drive specific sensing outputs, allowing auxin to control a myriad of processes. ARF6 and ARF8 are positive regulators of adventitious root initiation upstream of jasmonate, but the exact auxin co-receptor complexes controlling the transcriptional activity of these proteins has remained unknown. Here, using loss-of-function mutants we show that three Aux/IAA genes, IAA6, IAA9, and IAA17, act additively in the control of adventitious root (AR) initiation. These three IAA proteins interact with ARF6 and/or ARF8 and likely repress their activity in AR development. We show that TIR1 and AFB2 are positive regulators of AR formation and TIR1 plays a dual role in the control of jasmonic acid (JA) biosynthesis and conjugation, as several JA biosynthesis genes are up-regulated in the tir1-1 mutant. These results lead us to propose that in the presence of auxin, TIR1 and AFB2 form specific sensing complexes with IAA6, IAA9, and/or IAA17 to modulate JA homeostasis and control AR initiation.

P4131Abnormal flow pattern in the main pulmonary artery of Marfan patients is related to local dilation

Introduction

Marfan syndrome (MFS) is a hereditary connective tissue disorder caused by mutation in the FBN1 gene. Main pulmonary artery (MPA) dilation is very prevalent in MFS patients. Indeed, the old Ghent nosology considered main pulmonary artery (MPA) dilation as diagnostic criterion of MFS patients. Although clinical complications related to pulmonary dilation in MFS are rare, this may potentially lead to MPA dissection or be a marker of vascular disease in MFS. Studies regarding potential causes of MPA dilation in MFS patients are very scarce.

Purpose

Through 4D flow CMR, we aimed to assess whether flow abnormalities exist in the MPA of MFS patients and their relation to local diameter.

Methods

Fifty-five consecutive Marfan syndrome adults (MFS) and 22 healthy volunteers (HV) were prospectively enrolled. All subjects underwent non-contrast-enhanced 4D flow-MRI, obtaining 4D flow field and a 3D angiography. The MPA was segmented from the 3D angiography, and the segmentation was used to mask 4D velocity data. Four, equidistant analysis planes were placed in the MPA between the pulmonary valve and the pulmonary artery bifurcation. Common descriptors of large arteries hemodynamics were computed at each plane: maximum velocity, systolic flow reversal ratio (a descriptor of the amount of systolic backward flow) and circumferentially-averaged axial and circumferential wall shear stress (WSS). Pulmonary artery diameters were measured on axial images. MPA dilation was defined as a diameter larger than 27 mm in women and 29 mm in men. Systolic (SBP) and diastolic (DBP) systemic blood pressure were measured at the brachial artery with a calibrated cuff immediately after the scan.

Results

Compared with HV, MFS patients presented similar age, BSA, SBP and maximum blood velocity, but had larger MPA diameter (27.8 vs 25.1 mm, p<0.001) and higher DBP (75.5 vs 66.8 mmHg, p=0.003). According to the used threshold, 45% (27) of MFS patients had MPA dilation. Compared with HV, Marfan patients presented an increased systolic flow reversal ratio in the proximal part of the MPA (Figure 1). In MFS patients axial WSS was reduced in central sections of the MPA, while the circumferential component was not difference with respect to HV. All these flow abnormalities were also present in the subset of 28 MFS patients without pulmonary artery dilation. In multivariable analysis, MPA diameter was independently related to age (B=0.056; p=0.032), sex (B=−2.3; p=0.02) and axial (B=6.4; p=0.039) and circumferential (B=33.9; p<0.001) WSS.

Figure 1

Conclusions

Dilation of the main pulmonary artery is prevalent in Marfan syndrome patients. Abnormal increase in systolic vortexes and reduction in axial WSS were present in dilated and non-dilated MPA in MFS patients. Axial and circumferential WSS were independently related to MPA diameter. The eventual predictive role of abnormal pulmonary flow pattern in pulmonary artery dilation in MFS patients remain to be established

Acknowledgement/Funding

Instituto de Salud Carlos III (PI14/0106), La Maratό de TV3 (20151330), CIBERCV and FP7/People (267128)

P1821Proximal aorta longitudinal but not circumferential strain predicts aortic events and aortic root dilation rate in marfan syndrome patients

Background

The most common cardiovascular complications in Marfan syndrome (MFS) are aortic root dilation and type A aortic dissections. Elective aortic root surgery is indicated when maximum aortic diameter is larger than a defined threshold or in the case of fast-progressing dilation. However, maximum aortic diameter is limited for the prediction of aortic events. Indeed, a large international registry of acute aortic syndromes reported that as much as 40% of aortic dissections happen with maximum aortic diameter lower than 50 mm. Consequently, there is a need for new, non-invasive biomarkers to improve the prediction of aortic complications.

Purpose

The aim of the present study was to assess if proximal aorta circumferential and longitudinal strain and ascending aorta distensibility were associated with progressive aortic dilation and incidence of aortic events in Marfan syndrome patients.

Methods

Eighty seven Marfan syndrome patients free from previous cardiac/aortic surgery or dissection, were prospectively included in a multicenter follow-up. Patients were diagnosed by original Ghent criteria. Proximal aorta longitudinal and circumferential strain and distensibility were computed from baseline cine CMR images by means of feature-tracking. The predictive capacity of each stiffness biomarkers was separately tested with multivariable linear regression analysis (aortic growth) and with Cox logistic regression analysis (aortic events), both corrected for clinical and demographic variables, including baseline maximum aortic diameter.

Results

During a follow-up of 81.6±17 months, mean diameter growth-rate was 0.65±0.67 mm/year and z-score growth rate was 0.07±0.13 / year. Elective aortic root replacement was performed in 11 patients while two patients presented type A aortic dissection.Baseline proximal aorta longitudinal strain was independently related to diameter growth-rate (p=0.001), z-score growth-rate (p=0.018) and aortic events (p=0.018). Conversely, neither circumferential strain nor distensibility were independent predictors of diameter growth-rate (p=0.385 and p=0.381, respectively), z-score growth-rate (p=0.515 and p=0.484, respectively) and aortic events (p=0.064 and p=0.205, respectively).

Conclusions

Proximal aorta longitudinal strain predicts aortic root dilation and major aortic events in Marfan syndrome patients beyond aortic root diameter and clinical and demographic characteristics.

Acknowledgement/Funding

ISCIII PI14/0106, La Maratό de TV3 (20151330) and CIBERCV. Guala A. FP7/People n° 267128

6126Peripheral aneurysms in Marfan patients are common and are related to age and advanced aortic disease

Background

Peripheral aneurysms are not included in the diagnostic criteria for Marfan syndrome (MFS); however, their real prevalence in MFS is unknown. Furthermore, they are commonly seen in other genetic entities such as Loeys-Dietz syndrome.

We aimed to investigate the prevalence of peripheral aneurysm in Marfan syndrome.

Methods

Patients with clinical criteria of Marfan syndrome and identified FBN1 mutation were evaluated. Only patients with either MRI or CT angiography assessing peripheral vessels were included in this study. MRI and CT angiography studies were retrospectively evaluated to detect the presence of peripheral aneurysms. Aortic dissection-related arterial dilations were excluded. Aortic events and those related to aneurysm complications were collected during follow-up.

Results

Two hundred and nine patients with Marfan and FBN1 mutation were evaluated. Of these 136 (65.1%) had undergone either MRA or CTA with peripheral artery study during follow-up. Mean age at the last follow-up visit was 42.4±14.1yrs; 54.4% were men, and mean follow-up 7.3±3.1 years. Sixty-six aneurysms were identified in 42 (30.9%) patients. The most common locations were the iliac arteries in 23. The rest were: renal (7), vertebral (5), splenic (5), coeliac (3), brachiocephalic (1), subclavian (3), carotid (3), axillary (2), internal mammary (3), femoral (2), hypogastric (3), bronchial (2), coronary (1), hepatic (1), lumbar (1), gastroduodenal (1) and popliteal (1). Twenty-six patients (61.9%) had more than one peripheral aneurysm, and only 4 required surgery.

Patients with peripheral aneurysms were older (47.2±14.3yrs vs 40.2±13.6yrs, p=0.06) and more frequently men (69.0% vs 47.9% p=0.026). Although patients with peripheral aneurysms did not more frequently have aortic dissection (16.7% vs 17.0%, p=0.586), they did more frequently have aortic surgery (73.8% vs 47.9% p=0.05).

Conclusions

Peripheral aneurysms are present in one third of Marfan syndrome patients and are related to age and more advanced aortic disease. Systematic use of whole-body vascular assessment in Marfan patients can provide a comprehensive evaluation of the entire arterial system, identifying other sites of vascular involvement at risk of potential complications, and the subgroup of patients with more aggressive vascular disease expression.

477Partial fusion of two aortic valve leaflets is related to alterations in ascending aorta flow: 4D flow CMR study

Introduction

Bicuspid aortic valve (BAV) is the most common congenital valve defect. It consists in the fusion of two aortic valve leaflets, and it is associated with a high prevalence of proximal aorta dilation. Dilation is highly prevalent (around 30%) in BAV patient relatives with a tricuspid valve (TAV) identified by echocardiography. However, the presence of partial aortic valve leaflet fusion (also called mini-raphe or forme fruste BAV, see figure 1A) is easily missed by echocardiography. A recent study reported that 44% of patients from a small cohort of BAV patient relatives with aortic dilation followed by CT showed mini-raphe.

Purpose

We aimed to use 4D flow CMR to assess if the presence of mini-raphe is associated with aortic flow alterations, which may be concurs in the etiology of aortic dilation in BAV patient relatives.

Methods

Twenty BAV patients first-degree relatives with partial fusion (<50%) of aortic valve leaflets and proximal aorta dilation were identified by CT or cine CMR and prospectively included. One-hundred twenty-five BAV and 95 patients with TAV from our prospective dataset of 4D flow CMR were included for comparison. Propensity score matching was used throughout the study to correct the comparisons between mini-raphe and BAV and mini-raphe and TAV patients for differences in age, maximum aortic diameter, sex, height, weight, proximal aortic pulse wave velocity and, only for BAV, fusion pattern. The hemodynamic parameters previously related to aortic dilation were computed. They were jet angle, normalized flow displacement and systolic flow reversal ratio (SFRR, identifying through-plane vortexes) were computed and compared in the ascending aorta and in the aortic arch.

Results

The presence of mini-raphe was statistically-significantly associated with increase in jet angle (Figure 1B), flow displacement (Figure 1C) and vortexes (Figure 1D) in most of the ascending aorta and aortic arch when mini-raphe patients were compared with TAV patients. The severity of flow asymmetry found in mini-raphe patients was lower than the one characteristic of BAV patients, but vortexes were even higher in a small region at the distal ascending aorta.

Figure 1

Conclusion

Partial fusion of the aortic valve leaflets is related to increase in proximal aorta flow eccentricity and vorticity. These flow abnormalities are not as marked as those associated with BAV. Data regarding prevalence of mini-raphe as evaluated with CT or cine CMR are needed, especially in familiar of BAV patients.

Acknowledgement/Funding

European FP7/People 267128; Spanish Ministry of Economy and Competitiveness RTC-2016-5152-1 and Instituto de Salud Carlos III PI14/0106

4936Cardiac magnetic resonance strain analysis predicts functional recovery following acute ST-segment elevation myocardial infarction

Background

Late gadolinium enhancement (LGE) is the clinical reference standard for estimation of infarct extension and prediction of functional recovery following reperfused acute ST-segment elevation myocardial infarction (STEMI). Nevertheless, myocardial edema, microvascular obstruction and intramyocardial hemorrhage as well as the timing of image acquisition after contrast administration may influence the extent of LGE and underestimate the potential for recovery. Dobutamine stress testing has been recommended to more accurately predict functional recovery when infarct transmurality is between 25 to 75%. We hypothesized that cardiac magnetic resonance (CMR) tissue tracking strain analysis may provide additional value to LGE for the prediction of functional recovery.

Methods

In 370 patients with STEMI who underwent successful primary percutaneous revascularization and were studied with CMR within 3–5 days of the event, peak systolic longitudinal (LS), circumferential (CS) and radial (RS) strain were analyzed with routine SSFP images of 3 long-axis and a stack of short-axis slices (Tissue Tracking, CVI42®, Figure panel A and B). Inversion-recovery echogradient sequences were analyzed 20 minutes after contrast administration for LGE transmurality (Panel C). All per-segment analysis was performed according to the AHA 16-segment model. CMR was repeated at 6 months and functional recovery was defined as persistent normokinesia or improvement of wall motion score from baseline to 6-month CMR.

Results

At baseline CMR, of a total of 5920 segments 70.4% were normokinetic, 7.2% were hypokinetic, 21.9% were akinetic and 0.6% were dyskinetic. All strain parameters decreased significantly with worsening wall motion. At follow-up, 81.5% of the segments showed functional recovery. All strain parameters were significantly associated with functional recovery (p<0.001) and showed higher predictive value for improvement of wall motion than LGE transmurality (ROC AUC 0.713 LS, 0.710 CS, 0.683 RS and 0.660 LGE). For basal CMR dysfunctional segments, a CS <−10.7% showed the highest accuracy (66%) to predict wall motion improvement, with 58% sensitivity, 76% specificity, 75% positive predictive value (PPV) and 59% negative predictive value (NPV). These results were comparable to LGE transmurality <50% (65% accuracy, 59% sensitivity, 73% specificity, 74% positive predictive value and 58% negative predictive value). Nevertheless, adding CS analysis to a 50% LGE transmurality cutoff was the best combination for prediction of functional recovery and increased the overall accuracy to 70%, with 76% sensitivity, 64% specificity, 65% PPV and 75% NPV.

CS analysis in an inferior STEMI

Conclusions

Acute CMR tissue tracking strain analysis complements LGE assessment for prediction of functional recovery following an STEMI. The combination of LGE infarct transmurality under 50% and a CS strain higher than −10.7% showed the highest accuracy for prediction of recovery of function.

P3373Predictors of dilatation of ascending aorta in patients with bicuspid aortic valve, a longitudinal multicenter study

Introduction

The bicuspid aortic valve (BAV) is frequently associated to dilation of the ascending aorta. Some cross-sectional studies have related the aortic dilation with morphotype and valvular dysfunction. The aim of this longitudinal multicenter study was to analyze the progression of the aortic dilation and to identify its predictors.

Methods

We included 459 patients (mean age 52±17; 325 men 70.8%) with BAV, without aortic coarctation. The BAV morphotype, significant valvular dysfunction and dilation of the aortic root and ascending aorta were established by echocardiography. The patients were followed annually, with an average of 7.5±3.2 years.

Results

77% of the patients had BAV with a fusion between left and right cusps, 21% between right and non coronary cusps and 2% between left and non coronary cusps, with a raphe in 77% of these patients. Risk factors included: 35% hypertension, 20% smoking, 5% diabetes and 18% dyslipidemia. The baseline study showed a maximum root diameter of 36±6.2 mm and ascending aorta of 39±8.1 mm. In 7% the aortic root was>45 mm, while in 32% the ascending aorta>45 mm. There was no valvular dysfunction in 17% of patients, while the 8% had significant aortic stenosis and 35% significant aortic regurgitation. The annual growth of the aortic root was 0.33±0.2 mm and for the ascending aorta was 0.38±0.3 mm. At the end of follow-up, 16% of the patients had a root>45 mm and 41% an ascending aorta>45 mm. The annual progression of aortic diameters was not related to valvular morphotype, valvular dysfunction or cardiovascular risk factors. The univariate analysis showed a significant relationship between the annual growth of the aortic root and arterial hypertension (p=0.028) and the annual growth of the ascending aorta with the male sex (p=0.019), smoking (p=0.046) and significant (moderate or severe) aortic stenosis (p=0.013). Diabetes mellitus and the presence of raphe were found to be slightly protective (p=0.049 and p=0.031, respectively). In the multivariate analysis, only the male sex and significant aortic stenosis were independent predictors of dilation of the ascending aorta.

Conclusions

In patients with bicuspid aortic valve, the progression of the dilation of the aortic root is related to hypertension and the growth of the ascending aorta with the male sex and the presence of significant aortic stenosis. Both bicuspid valve morphotype, basal aortic diameter or age were not related to the progression of aortic dilation.

Pinoresinol-lariciresinol reductases, key to the lignan synthesis in plants

This paper provides an overview on activity, stereospecificity, expression and regulation of pinoresinol-lariciresinol reductases in plants. These enzymes are shared by the pathways to all 8-8' lignans derived from pinoresinol. Pinoresinol-lariciresinol reductases (PLR) are enzymes involved in the lignan biosynthesis after the initial dimerization of two monolignols. They catalyze two successive reduction steps leading to the production of lariciresinol or secoisolariciresinol from pinoresinol. Two secoisolariciresinol enantiomers can be synthetized with different fates. Depending on the plant species, these enantiomers are either final products (e.g., in the flaxseed where it is stored after glycosylation) or are the starting point for the synthesis of a wide range of lignans, among which the aryltetralin type lignans are used to semisynthesize anticancer drugs such as Etoposide^®. Thus, the regulation of the gene expression of PLRs as well as the possible specificities of these reductases for one reduction step or one enantiomer are key factors to fine-tune the lignan synthesis. Results published in the last decade have shed light on the presence of more than one PLR in each plant and revealed various modes of action. Nevertheless, there are not many results published on the PLRs and most of them were obtained in a limited range of species. Indeed, a number of them deal with wild and cultivated flax belonging to the genus Linum. Despite the occurrence of lignans in bryophytes, pteridophytes and monocots, data on PLRs in these taxa are still missing and indeed the whole diversity of PLRs is still unknown. This review summarizes the data, published mainly in the last decade, on the PLR gene expression, enzymatic activity and biological function.

The control exerted by ABA on lignan biosynthesis in flax (Linum usitatissimum L.) is modulated by a Ca2+ signal transduction involving the calmodulin-like LuCML15b

The LuPLR1 gene encodes a pinoresinol lariciresinol reductase responsible for the biosynthesis of (+)-secoisolariciresinol, a cancer chemopreventive lignan, highly accumulated in the seedcoat of flax (Linum usitatissimum L.). Abscisic acid (ABA) plays a key role in the regulation of LuPLR1 gene expression and lignan accumulation in both seeds and cell suspensions, which require two cis-acting elements (ABRE and MYB2) for this regulation. Ca²⁺ is a universal secondary messenger involved in a wide range of physiological processes including ABA signaling. Therefore, Ca²⁺ may be involved as a mediator of LuPLR1 gene expression and lignan biosynthesis regulation exerted by ABA. To test the potential implication of Ca²⁺ signaling, a pharmacological approach was conducted using both flax cell suspensions and maturing seed systems coupled with a ß-glucuronidase reporter gene experiment, RT-qPCR analysis, lignan quantification as well as Ca²⁺ fluorescence imaging. Exogenous ABA application results in an increase in the intracellular Ca²⁺ cytosolic concentration, originating mainly from the extracellular medium. Promoter-reporter deletion experiments suggest that the ABRE and MYB2 cis-acting elements of the LuPLR1 gene promoter functioned as Ca²⁺-sensitive sequences involved in the ABA-mediated regulation. The use of specific inhibitors pointed the crucial roles of the Ca²⁺ sensors calmodulin-like proteins and Ca²⁺-dependent protein kinases in this regulation. This regulation appeared conserved in the two different studied systems, i.e. cell suspensions and maturing seeds. A calmodulin-like, LuCML15b, identified from gene network analysis is proposed as a key player involved in this signal transduction since RNAi experiments provided direct evidences of this role. Taken together, these results provide new information on the regulation of plant defense and human health-promoting compounds, which could be used to optimize their production.