Molecular and haemodynamic interplay in bicuspid aortic valve aortopathy: segmental differences across the aortic circumference

Background

Bicuspid aortic valve (BAV) patients develop ascending aortic (AAo) dilation. The pathogenesis of BAV-aortopathy (genetic vs. hemodynamic) remains unclear.

Purpose

To identify regional changes around the AAo wall in BAV patients with aortopathy integrating clinical imaging and molecular data.

Methods

BAV patients with aortopathy (n=20) were recruited prospectively to surgically collect aortic tissue and perform four-dimensional cardiac magnetic resonance (CMR) scans. Molecular markers were measured analysing the tissue biopsies (n=15) and wall shear stress (WSS) across the AAo circumference was calculated from the 4D CMR data (n=11 patients, and n=7 additional healthy volunteers for comparison). Dilated (anterior/right) vs. non-dilated (posterior/left) circumferential segments were profiled for whole genomic microRNAs (Next Generation RNA-Sequencing, miRCURY LNA PCR), proteins content (Tandem Mass Spectrometry) and elastin fragmentation and degeneration (histomorphometric analysis). Picture 1 summarises the study approach (including a map of the AAo divided in the following segments: A=anterior, AR=anterior-right, PR=posterior-right, P=posterior, PL=posterior-left, AL=anterior-left).

Results

Integrated bioinformatic analyses of RNA-sequencing and proteomic datasets identified 5 microRNAs (miR-128-3p, miR-210-3p, miR-150-5p, miR-199b-5p, and miR-21-5p) differentially expressed across the AAo circumference. Among them, three miRNAs (miR-128-3p, miR-150-5p, and miR-199b-5p) were predicted to have an effect on eight common target genes, whose expression was dysregulated according to proteomic analyses and involved in vascular endothelial growth factor signalling, hippo signaling and arachidonic acid pathway. Decreased elastic fibre levels and elastic layer thickness were observed in the dilated segments in the histomorphometric analysis. Increased WSS and flow-velocity, helical streamlines and asymmetrical flow were observed at the anterior/right wall in asymmetrically and symmetrically dilated patients (the latter exhibiting higher WSS), compared to healthy volunteers.

Conclusion

This study has newly revealed concomitant expressional dysregulation of miRNAs, proteins, and elastic fibres on the anterior/right wall in dilated BAV patients, corresponding to regions of elevated WSS, contributing to advance the understanding of the interplay of genetic and hemodynamic factors underpinning BAV aortopathy.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): British Heart Foundation and Above & Beyond

Feasibility of a longitudinal statistical atlas model to study aortic growth in congenital heart disease

Background

Studying anatomical shape progression over time is of utmost importance to refine our understanding of clinically relevant processes. These include vascular remodelling, such as aortic dilation, which is particularly important in some congenital heart defects (CHD).

Purpose

A novel methodological framework for analysing three-dimensional (3D) shape changes over time (“growth”) has been applied for the first time in a CHD scenario, i.e., bicuspid aortic valve (BAV) disease, the most common CHD.

Methods

Three-dimensional aortic shapes (n=94) reconstructed as surface meshes from cardiovascular magnetic resonance imaging (MRI) data represented the input for a longitudinal shape atlas model, using multiple scans over time (n=2–4 scans per patient). This model relies on diffeomorphic transformations in the absence of point-to-point correspondence, and on the correct combination of initialization, estimation, and registration parameters.

Results

We computed the 3D shape trajectory of an average disease progression over time in our cohort (Picture 1, grey to blue shapes), as well as time-dependent parameters, geometric variations and the average shape of the population (Picture 1, red shape). Results cover a spatiotemporal spectrum of visual and numerical information that can be further used to investigate clinical associations and stratify patients, as such capturing aortic remodelling in the presence of BAV aortopathy.

Conclusion

This proof-of-concept study demonstrates the feasibility of applying advanced statistical shape models to track disease progression and stratify patients with CHD.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): British Heart Foundation and NIHR BRC

Left ventricular morphology in patients with aortic coarctation and bicuspid aortic valve: novel insights from a statistical shape modelling framework

Background

The functional implications of left ventricular (LV) morphological characterization in congenital heart disease (CHD) are not widely explored.

Purpose

This study qualitatively and quantitatively assessed LV shape associations with a) LV function and b) thoracic aortic morphology in patients with aortic coarctation (CoA) with/without bicuspid aortic valve (BAV).

Methods

A statistical shape modelling (SSM) framework was employed to analyse three-dimensional (3D) LV shapes from cardiac magnetic resonance (CMR) imaging data in n=110 cases including: isolated CoA (n=25), CoA+BAV (n=30), isolated BAV (n=30), and age-matched healthy controls (n=25). Average 3D templates (Picture 1) and deformations were computed. Correlations between shape data and CMR-derived morphometric parameters (i.e. sphericity, conicity) as well as CMR-derived global and apical strain values were assessed to elucidate possible functional implications. The relationship between LV shape features and arch architecture (i.e. gothicity, tortuosity) was also explored by means of regression analysis.

Results

The LV template was shorter and more spherical in CoA patient (Picture 1), as also confirmed by statistical analysis of the SSM-derived shape modes. LV sphericity, which was higher in CoA, was associated (p≤0.04) with lower global longitudinal, radial and circumferential strain, irrespective of the presence of aortic stenosis and/or regurgitation. Conversely, neither LV morphology nor LV strain was not associated with arch architecture.

Conclusions

Differences in LV morphology were observed between CoA and BAV patients. Increasing LV sphericity was associated with reduced strain, independent of aortic arch architecture and functional aortic valve disease.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): British Heart Foundation and NIHR BRC

Diagnostic and prognostic role of peak troponin T in patients with acute coronary syndromes and non-obstructive coronary arteries

Background

Up to 10% of patients who present with an acute coronary syndrome have a myocardial infarction with non-obstructive coronary arteries (MINOCA). Troponin T predicts infarct size and outcomes in patients with ST-elevation myocardial infarction. The value of peak troponin T in patients with a working diagnosis of MINOCA is not well understood.

Purpose

The aim of this study is to investigate the diagnostic and prognostic role of troponin in patients with MINOCA.

Methods

Consecutive patients with a working diagnosis of MINOCA from a single tertiary centre who underwent comprehensive cardiovascular magnetic resonance (CMR) imaging with late gadolinium enhancement (LGE) were followed prospectively. Peak troponin T was identified during the index admission and divided into deciles and quartiles for analysis. The primary endpoint was all-cause mortality.

Results

Among 796 patients undergoing CMR, 719 met the study criteria and had underwent a diagnostic quality scan. The peak Troponin T threshold for optimal diagnostic sensitivity and specificity was 211 ng/L. Peak troponin T ≥211 ng/L and time to CMR of ≤14 days has a sensitivity of 94%, specificity of 35%, PPV 57% and NPV 94% for the CMR making a diagnosis. Each increase in troponin decile increases the mean diagnostic yield of the CMR by 3.65% (p<0.001, 95% CI 3.38 – 3.91; R2 0.84; Figure 1).

If the troponin is in the lowest decile and the CMR is performed at ≤14 days, the diagnostic yield is still 72%. There is no overall difference in median troponin in patients who died and those who survived (229 ng/l v. 424 ng/l; p=0.157), however mortality is significantly lower in the highest two troponin quartiles (6.9% versus 11.9%; p=0.009; Figure 2).

Conclusion

Peak troponin T is readily available during the index admission in patients presenting with MINOCA and provides useful diagnostic and prognostic information for the attending cardiologist.

Funding Acknowledgement

Type of funding sources: None. Figure 1. CMR diagnosis by troponin decileFigure 2. Mortality by troponin quartile

Sex and age differences in patients with acute coronary syndrome and non-obstructive coronary arteries: presentation and outcome

Aims

A substantial number of patients present with acute coronary syndrome (ACS) and non-obstructive coronary arteries. Sex and age differences in these patients are not well understood. This study aims to evaluate the impact of sex and age on clinical presentation and outcome in patients with ACS and non-obstructive coronary arteries, with either an ischaemic or non-ischaemic cause.

Methods and results

Consecutive patients with an ACS and non-obstructive coronary arteries (n=719) from a single tertiary centre underwent comprehensive cardiovascular magnetic resonance (CMR) imaging with late gadolinium enhancement (LGE). The primary endpoint was all-cause mortality. CMR was performed at a median time of 30 days after presentation and identified a diagnosis in 74% of patients. Patients with an ischaemic or non-ischaemic aetiology (n=529) on CMR were followed prospectively. All-cause mortality was 11% over a median follow up of 4.9 years, with no significant difference between sexes (11% versus 11% p=0.732). Women were more likely to have an ischaemic aetiology on CMR (40% v 31%, p=0.037). Age group (HR 1.48, p=0.002), log peak troponin (HR 0.78, p=0.033) and LVEF (HR 0.98, p=0.032) were independent predictors of mortality. Men aged >60 years with a non-ischaemic aetiology on their CMR were at higher risk of death than women >60 years (p=0.003).

Conclusions

There is no difference in all-cause mortality between sexes in patients presenting with ACS and non-obstructive coronary arteries but increasing age is an important predictor of mortality in both sexes.

Funding Acknowledgement

Type of funding sources: None. Sex differences in CMR diagnosisSex, age and mortality

The role of peak troponin in patients with a working diagnosis of myocardial infarction with non-obstructive coronary arteries (MINOCA)

Funding Acknowledgements

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Rosetrees Trust James Tudor Foundation

Background

6-10% of patients who present with an acute coronary syndrome have a myocardial infarction with non-obstructive coronary arteries (MINOCA). Troponin T predicts infarct size and outcomes in patients with ST-elevation myocardial infarction. The value of peak troponin T in patients with a working diagnosis of MINOCA is not well understood.

Purpose

The aim of this study is to investigate the diagnostic and prognostic role of troponin in patients with MINOCA. 

Methods

Consecutive patients with a working diagnosis of MINOCA (n = 719) from a single tertiary centre who underwent comprehensive cardiovascular magnetic resonance (CMR) imaging with late gadolinium enhancement (LGE) were followed prospectively. The primary endpoint was all-cause mortality.

Results

Peak troponin T ≥211 ng/L and time to CMR of ≤17 days have a positive predictive value of 94% for being able to make a diagnosis on CMR. If the scan was performed in ≤17 days the diagnostic yield was still 75% even in the lowest troponin decile, but this was 59% if performed after 17 days. Each increase in troponin decile increases the mean diagnostic yield of the CMR by 3.7% (p < 0.001, 95% CI 3.4 – 3.9; R2 0.84; Figure 1). There is no overall difference in median troponin in patients who died and those who survived (229 ng/l v. 424 ng/l; p = 0.157), however mortality is significantly lower in the highest two troponin quartiles (11.9% versus 6.9%; p = 0.009, figure 2). 

Conclusions

Peak troponin T and time to CMR can be used by cardiologists to determine the likelihood of making a diagnosis using CMR. A higher troponin quartile is associated with lower mortality.

Sex and age differences in patients with a working diagnosis of myocardial infarction with non-obstructive coronary arteries (MINOCA): presentation and outcome

Funding Acknowledgements

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Rosetrees Trust James Tudor Foundation

Background Myocardial infarction with non-obstructive coronary arteries (MINOCA) is an increasingly recognised working diagnosis. Sex and age differences in MINOCA are not well understood.

Purpose  This study aims to evaluate the impact of sex and age in patients with MINOCA due to ischaemic and non-ischaemic causes on clinical presentation and outcome.

Methods and Results Consecutive patients with a working diagnosis of MINOCA (n = 719) from a single tertiary centre who underwent comprehensive cardiovascular magnetic resonance (CMR) imaging with late gadolinium enhancement (LGE) were followed prospectively. The primary endpoint was all-cause mortality.  CMR was performed at a median time of 30 days after presentation and identified a diagnosis in 74% of patients. Men were more likely to have a non-ischaemic cause on CMR (55% v. 41%, p < 0.001) and less likely to have a normal/non-specific scan (21% v. 32%, p = 0.001, figure 1).  All-cause mortality was 9.5% over a median follow up of 4.9 years, with no significant difference between sexes (8.7% versus 10.1% p = 0.456).  Age group (HR 1.61, p < 0.001) and LVEF (HR 0.98, p = 0.020) were independent predictors of mortality. Men aged >60 years with a non-ischaemic aetiology on their CMR were at higher risk of death than women with non-ischaemic causes >60 years (p = 0.003, figure 2).

Conclusions There is no difference in all-cause mortality between sexes in MINOCA but increasing age is the most important predictor of mortality in both sexes.

P4163Long term comparison between homograft vs stented bio-prostheses for pulmonary valve replacement in tetralogy of Fallot patients

Background

Tetralogy of Fallot (TOF) repair results in long term chronic pulmonary regurgitation requiring pulmonary valve replacement (PVR). Homograft and stented bio-prosthesis are currently used for PVR but whether one should be considered superior to another remains unknown.

Aim

To compare echocardiographic and clinical outcomes after PVR with Homograft vs stented bioprosthesis in patients with previous TOF repair.

Methods

137 patients who underwent PVR with stented bioproshesis were compared with 80 patients who received an homograft using Mixed linear model and multivariate Cox regression.

Results

Homograft were associated with a significantly lower transpulmonary gradient postoperatively (P=0.04) and after a mean follow-up 6 years (table). Homograft were associated with a significantly lower risk of reintervention (HR 0.24; 95% CI 0.07–0.85, p=0.026) while long term mortality was comparable between the two groups (P=0.1).

Echocardiographic findings BIO HOMOGRAFT P N 137 80 Preoperatively   TV regurgitation (mean, sd) 1.80 (0.63) 1.94 (0.81) 0.353   TV regurgitation pressure drop (mean,sd) 35.15 (15.49) 45.34 (25.24) 0.009   PV regurgitation (mean,sd) 3.63 (0.52) 3.34 (0.64) 0.004   PV systolic peak gradient (mean, sd) 25.07 (17.05) 30.68 (21.70) 0.138 Early postoperatively   TV regurgitation (mean,sd) 1.52 (0.54) 1.54 (0.55) 0.858   TV regurgitation pressure drop (mean,sd) 30.10 (13.82) 29.13 (13.98) 0.733   PV regurgitation (mean,sd) 1.50 (0.54) 1.64 (0.53) 0.224   PV systolic peak gradient (mean,sd) 24.05 (11.10) 20.16 (14.19) 0.045 Latest follow_up   TV regurgitation (mean,sd) 1.63 (0.61) 1.83 (0.80) 0.195   TV regurgitation pressure drop (mean,sd) 37.46 (18.84) 32.58 (13.47) 0.233   PV regurgitation (mean,sd) 2.06 (0.77) 2.07 (0.94) 0.982   PV systolic peak gradient (mean,sd) 32.22 (18.17) 21.25 (13.47) 0.001 TAPSE: Tricuspid annular plane systolic excursion; TV: tricuspid valve; PV: pulmonary valve.

PV re-intervention

Conclusions

When compared to stented bio-prostheses, homografts were associated better early and late hemodynamic profile and a significantly lower risk of re-intervention. Homograft should be considered the first choice in patients undergoing PVR after TOF repair.

Wave intensity analysis in the internal carotid artery of hypertensive subjects using phase-contrast MR angiography and preliminary assessment of the effect of vessel morphology on wave dynamics

Objective: Hypertension is associated with reduced cerebral blood flow, but it is not known how this impacts on wave dynamics or potentially relates to arterial morphology. Given the location of the internal carotid artery (ICA) and risks associated with invasive measurements, wave dynamics in this artery have not been extensively assessed in vivo. This study explores the feasibility of studying wave dynamics in the internal carotid artery non-invasively. Approach: Normotensive, uncontrolled and controlled hypertensive participants were recruited (daytime ambulatory blood pressure  <135/85 mmHg and  >135/85 mmHg, respectively; n  =  38). Wave intensity, reservoir pressure and statistical shape analyses were performed on the right ICA and ascending aorta high-resolution phase-contrast magnetic resonance angiography data. Main results: Wave speed in the aorta was significantly lower in normotensive compared to hypertensive participants (6.7  ±  1.8 versus 11.2  ±  6.2 m s⁻¹ for uncontrolled and 11.8  ±  4.6 m s⁻¹ for controlled hypertensives, p  =  0.02), whilst there were no differences in wave speed in the ICA. There were no significant differences between the groups for the wave intensity or reservoir pressure. Interestingly, a significant association between the anatomy of the ICA and wave energy (FCW and size, r²  =  0.12, p  =  0.04) was found. Significance: This study shows it is feasible to study wave dynamics in the ICA non-invasively. Whilst changes in aortic wave speed confirmed an expected increase in arterial stiffness, this was not observed in the ICA. This might suggest a protective mechanism in the cerebral circulation, in conjunction with the effect of vessel tortuosity. Furthermore, it was observed that ICA shape correlated with wave energy but not wave speed.

In vitro metabolism of 1,3-dioxane, 1,3-oxathiolane, and 1,3-dithiane derivatives of theophylline: a structure-metabolism correlation study

Correlation between structure and metabolism was studied within a series of cyclic acetal and thioacetal theophylline derivatives. All the compounds showed marked regioselectivity in in vitro metabolism, the metabolites arising only from 7-cycloalkyl side chain transformation. The 1,3-dioxane derivative, besides N-dealkylation to theophylline, underwent enzymatic ring cleavage, through the oxidation of the acetal carbon and subsequent rearrangement. Thus the acetal group was converted enzymatically to an ester. A similar transformation, catalyzed by cytochrome P450-dependent monooxygenases, was previously found for the 1,3-dioxolane ring of doxophylline. The cyclic thioacetal derivatives (i.e. 1,3-oxathiolane and 1,3-dithiane) were not cleaved during oxidative metabolism. The metabolites arise only from the oxidation of the sulfur atom, the major nucleophilic center in the molecule. No N-dealkylation to theophylline was observed. Enzymatic sulfoxidation proceeded diastereoselectively in both the 1,3-oxathiolane and 1,3-dithiane rings, the trans isomers being the major ones with a ratio trans: cis 75:25 and 60:40 respectively. The sulfoxides were stable to hydrolysis and were not further metabolized. Neither disulfoxides nor sulfones were detected in the incubations.

Metabolism of 7-(1,3-thiazolidin-2-ylmethyl)theophylline by rat liver microsomes. Evidence for a monooxygenase-dependent step in 1,3-thiazolidine ring cleavage

Metabolic transformation of the mucoregulator and bronchodilator 7-(1,3-thiazolidin-2-ylmethyl)theophylline was studied in vitro with a rat liver microsomal preparation containing a NADPH-generating system. The only metabolite observed was 7-theophyllinacetaldehyde. In contrast to previous literature pointing out the chemical nature of 2-substituted thiazolidine ring cleavage, the formation of 7-theophyllinacetaldehyde was mediated by monooxygenase-dependent oxidation. Possibly an unstable sulfoxide was the first metabolic product, rapidly converted to 7-theophyllinacetaldehyde by hydrolysis. The sulfoxidation was apparently catalyzed mainly by flavin-containing monooxygenases, as selective thermal inactivation and methymazole significantly reduced the rate of formation of the metabolite. No N7-dealkylation pathway producing theophylline was detected, indicating a high regioselectivity in in vitro metabolism, due to the nucleophilicity of the sulfur atom.

The metabolic fate of the anti-parkinsonian drug budipine in rats

The metabolic fate of the anti-Parkinsonian drug budipine was studied in rats after oral administration. The presence of an aromatic hydroxylation product, metabolite M1, and its O-sulphate conjugate was confirmed. Three new minor metabolites, budipine N-oxide, metabolite M1 N-oxide and a secondary metabolite derived from M1 via hydroxylation of a methyl of the tert-butyl group, were isolated and identified in rat urine. The presence of a metabolite M1-glucuronic acid conjugate, was also established through different enzymatic treatments of the rat urine.

Metabolism of 7-(1,3-dithiolan-2-ylmethyl)-1,3-dimethylxanthine by rat liver microsomes. Diastereoselective metabolism of the 1,3-dithiolane ring

The metabolic transformation of the antibronchospastic compound ABC-99 [7-(1,3-dithiolan-2-ylmethyl)-1,3-dimethylxanthine] was studied in vitro with a rat liver microsomal preparation containing an NADPH-generating system. Thirty percent of the ABC-99 was metabolized and the only metabolic pathway observed as the oxidation of the 1,3-dithiolane ring. Two distinct sulfoxides were formed diastereoselectively, the trans isomer being the major product in the ratio 7:3. In contrast to the 1,3-dioxolane ring of doxophylline, the 1,3-dithiolane ring of ABC-99 did not undergo oxidative opening through acetal carbon oxidation. Furthermore no N-dealkylation to theophylline was observed. This high regioselectivity in in vitro metabolism was most likely due to the nucleophilicity of the sulfur atom. The diastereoselective sulfoxidation was apparently catalyzed by flavin-dependent monooxygenases, as no effect was observed with CO treatment, whereas selective thermal inactivation significantly reduced the rate of sulfoxidation.

Metabolism of 1,1-dichloro-cis-diphenylcyclopropane by rat liver microsomes

The metabolic fate of the anti-estrogen 1,1-dichloro-cis-diphenylcyclopropane (Analog II), was studied in vitro with phenobarbital-induced rat liver microsomal fractions. The presence of five metabolites was directly or indirectly established. Biotransformation products were isolated by TLC and HPLC techniques and, when possible, the structures were confirmed through comparison with synthetic samples. The presence of an allyl chloride, highly reactive, metabolic intermediate was stated.

In vitro metabolism of 2-(5-ethylpyridin-2-yl)benzimidazole

The in vitro metabolic transformation of the anti-inflammatory agent 2-(5-ethylpyridin-2-yl)benzimidazole (KB-1043) was studied with phenobarbital and 3-methylcholanthrene induced rat liver microsomal fractions containing an NADPH-generating system. The major metabolite was a benzylic oxidation product and a secondary metabolite was also recovered. The metabolites were isolated by TLC and HPLC techniques and identified by comparison with known pure compounds.

'In vitro' metabolism of N-picolyl-3,5-dimethylbenzamides

'In vitro' metabolism of three isomeric N-picolyl-3,5-dimethylbenzamides was studied. The metabolites were isolated through TLC and HPLC techniques and identified by direct comparison with authentic compounds. The results of phenobarbital and 3-methyl-cholantrene inductions are given.

Metabolism of doxophylline by rat liver microsomes

The metabolic transformation of the bronchospasmolytic agent doxophylline (2-(7'-theophyllinemethyl)-1,3-dioxolane) was studied in vitro with phenobarbital-induced rat liver microsomal fraction containing the NADPH-generating system. Doxophylline was poorly metabolized as 95% of the recovered material was parent compound. The major metabolite resulted: 2'-hydroxyethyl ester of theophylline acetic acid. This was an unusual metabolite which possibly arose from dioxolane C2 enzymatic oxydation and subsequent ring opening. Theophylline was a minor metabolite. The per cent ratio of the two metabolites was 4:1; as we did not detected the presence of any compounds formed from N-demethylation, we concluded that doxophylline underwent a regiospecific metabolism on the N7 side chain.

[Changes in salivary immunoglobulin levels after cryosurgery of benign and malignant lesions of the oral cavity]

The authors have evaluated variations in salivary IgA, IgG, IgM levels after cryosurgical treatment of benign and malignant oral lesions. Salivary immunoglobulin levels were measured by radial immunodiffusion before a single cryotreatment 7 and 14 days after. Seven days after cryosurgery of the lesions, there was a statistically significant increase in salivary IgG and IgM levels (p less than 0,02). These results suggest that, at the time of maximal oral cavity inflammation, 7 days after cryotreatment, there was a transudation of these immunoglobulins from serum into saliva. Salivary IgA levels decrease in a significant way (p less than 0,02) on the 14th day; this behaviour seems to be strictly connected with tumor regression after cryosurgery.

Bromination of 3-acyl-4-hydroxy-6 methyl-2H-thiopyran-2-ones. II

The brominations of various 3-acyl-4-hydroxy-6-methyl-2H-thiopyran-2-ones as well as of 3-acyl-4-methoxy-6-methyl-2H-thiopyran-2-ones, bearing linear and branched acyl chains ranging from four to eight carbon atoms are described. The antibacterial and antimycotic activities of the new compounds are also reported.