Characterization and implications of intracoronary hemodynamic assessment during coronary spasm provocation testing

BACKGROUND

Current diagnostic criteria for coronary spasm are based on patient's symptoms, ECG shifts and epicardial vasoconstriction during acetylcholine (ACh) spasm testing.

AIMS

To assess the feasibility and diagnostic value of coronary blood flow (CBF) and resistance (CR) assessment as objective parameters during ACh testing.

METHODS

Eighty-nine patients who underwent intracoronary reactivity testing including ACh testing with synchronous Doppler wire-based measurements of CBF and CR were included. Coronary microvascular and epicardial spasm, respectively, were diagnosed based on COVADIS criteria.

RESULTS

Patients were 63 ± 13 years old, predominantly female (69%) and had preserved LV ejection fraction (64 ± 8%). Overall, assessment of CBF and CR during ACh testing revealed a decrease in CBF of 0.62 (0.17-1.53)-fold and an increase of CR of 1.45 [0.67-4.02]-fold in spasm patients compared to 2.08 (1.73-4.76) for CBF and 0.45 (0.44-0.63) for CR in patients without coronary spasm (both p < 0.01). Receiver operating characteristic revealed a high diagnostic ability of CBF and CR (AUC 0.86, p < 0.001, respectively) in identifying patients with coronary spasm. However, in 21% of patients with epicardial spasm and 42% of patients with microvascular spasm a paradoxical response was observed.

CONCLUSIONS

This study demonstrates feasibility and potential diagnostic value of intracoronary physiology assessments during ACh testing. We observed opposite responses of CBF and CR to ACh in patients with positive vs. negative spasm test. While a decrease in CBF and an increase in CR during ACh seem pathognomonic for spasm, some patients with coronary spasm demonstrate paradoxical ACh response demanding further scientific investigations.

Coronary Spasm: Ethnic and Sex Differences

Coronary spasm (CS), which may occur at the epicardial (focal or diffuse spasm) and/or microvascular (microvascular spasm) level, is a well-established cause of myocardial ischaemia, in particular in patients with anginal chest pain despite unobstructed coronary arteries. The diagnosis of CS can be confirmed during coronary angiography by an additional provocation test with vasoactive substances such as acetylcholine. Due to partially inconsistent data from large clinical studies, especially between Asian and white CS patients, ethnic differences concerning the prevalence and angiographic patterns of CS seem to exist. Furthermore, several studies in patients with coronary vasomotor disorders pointed towards differences among male and female CS patients. This article gives an overview of ethnic- and sex-related differences in patients with CS.

Deletion of endothelial leptin receptors in mice promotes diet-induced obesity

Obesity promotes endothelial dysfunction. Endothelial cells not only respond, but possibly actively promote the development of obesity and metabolic dysfunction. Our aim was to characterize the role of endothelial leptin receptors (LepR) for endothelial and whole body metabolism and diet-induced obesity. Mice with tamoxifen-inducible, Tie2.Cre-ER^T2-mediated deletion of LepR in endothelial cells (End.LepR knockout, KO) were fed high-fat diet (HFD) for 16 weeks. Body weight gain, serum leptin levels, visceral adiposity and adipose tissue inflammation were more pronounced in obese End.LepR-KO mice, whereas fasting serum glucose and insulin levels or the extent of hepatic steatosis did not differ. Reduced brain endothelial transcytosis of exogenous leptin, increased food intake and total energy balance were observed in End.LepR-KO mice and accompanied by brain perivascular macrophage accumulation, whereas physical activity, energy expenditure and respiratory exchange rates did not differ. Metabolic flux analysis revealed no changes in the bioenergetic profile of endothelial cells from brain or visceral adipose tissue, but higher glycolysis and mitochondrial respiration rates in those isolated from lungs. Our findings support a role for endothelial LepRs in the transport of leptin into the brain and neuronal control of food intake, and also suggest organ-specific changes in endothelial cell, but not whole-body metabolism.

Protein Tyrosine Phosphatase 1B Deficiency in Vascular Smooth Muscle Cells Promotes Perivascular Fibrosis following Arterial Injury

Background  Smooth muscle cell (SMC) phenotype switching plays a central role during vascular remodeling. Growth factor receptors are negatively regulated by protein tyrosine phosphatases (PTPs), including its prototype PTP1B. Here, we examine how reduction of PTP1B in SMCs affects the vascular remodeling response to injury.

Methods  Mice with inducible PTP1B deletion in SMCs (SMC.PTP1B-KO) were generated by crossing mice expressing Cre.ER ^T2 recombinase under the Myh11 promoter with PTP1B ^flox/flox mice and subjected to FeCl ₃ carotid artery injury.

Results  Genetic deletion of PTP1B in SMCs resulted in adventitia enlargement, perivascular SMA ⁺ and PDGFRβ ⁺ myofibroblast expansion, and collagen accumulation following vascular injury. Lineage tracing confirmed the appearance of Myh11 -Cre reporter cells in the remodeling adventitia, and SCA1 ⁺ CD45 ^- vascular progenitor cells increased. Elevated mRNA expression of transforming growth factor β (TGFβ) signaling components or enzymes involved in extracellular matrix remodeling and TGFβ liberation was seen in injured SMC.PTP1B-KO mouse carotid arteries, and mRNA transcript levels of contractile SMC marker genes were reduced already at baseline. Mechanistically, Cre recombinase (mice) or siRNA (cells)-mediated downregulation of PTP1B or inhibition of ERK1/2 signaling in SMCs resulted in nuclear accumulation of KLF4, a central transcriptional repressor of SMC differentiation, whereas phosphorylation and nuclear translocation of SMAD2 and SMAD3 were reduced. SMAD2 siRNA transfection increased protein levels of PDGFRβ and MYH10 while reducing ERK1/2 phosphorylation, thus phenocopying genetic PTP1B deletion.

Conclusion  Chronic reduction of PTP1B in SMCs promotes dedifferentiation, perivascular fibrosis, and adverse remodeling following vascular injury by mechanisms involving an ERK1/2 phosphorylation-driven shift from SMAD2 to KLF4-regulated gene transcription.

How myocardial work could be relevant in patients with an aortic valve stenosis?

Funding Acknowledgements

Type of funding sources: None.

Background

Speckle tracking based myocardial work calculation is an attractive method to assess left ventricular (LV) myocardial function. In case of aortic stenosis (AS), assessment of work indices is challenging because it requires an accurate evaluation of LV-pressure curves. Therefore, we sought to evaluate the performances of two distinct methods for the estimation of myocardial work indices and to provide a quantitative comparison with invasively measured data.

Methods

Model-based and template-based methods were defined and applied for the evaluation of LV pressures on 67 AS patients. Global Constructive (GCW), Wasted (GWW), Positive (GPW), Negative (GNW) myocardial work and Global Work Efficiency (GWE) and Index (GWI) parameters were calculated using the available software computing the indices using brachial blood pressure and trans-aortic mean pressure gradient for estimating the LV pressures versus using a model-based and homemade software. A complete comparison was performed with invasive measurements.

Results

Patients were characterized by mean pressure gradient of 49.8 ± 14.8 mmHg, LV ejection fraction of 59 ± 8%, the global longitudinal strain was -15.0 ± 4.04%, GCW was 2107 ± 800mmHg.% (model-based method) and 2483 ± 1068mmHg.% (template-based method). The root mean square error (RMSE) and correlation were calculated for each patient and for each pressure estimation methods. The mean RMSE are 33.9mmHg and 40.4mmHg and the mean correlation coefficients are 0.81 and 0.72 for the model-based and template-based methods respectively. Correlation coefficient and Bland-Altman analysis were performed for the six work indices. The two methods present correlation coefficient r2 &gt; 0.75 for almost all the indices.

Conclusion

The two non-invasive methods of LV pressure estimation and the work indices computation correlate with invasive measurements and computations for AS patients. Although the model-based approach requires less information and is associated with slightly better performances, the implementation of template-based method is easier and seems more appropriate in a clinical practice. Abstract Figure. SUMMARY

A new electron diffraction approach for structure refinement applied to Ca3Mn2O7

The digital large-angle convergent-beam electron diffraction (D-LACBED) technique is applied to Ca3Mn2O7 for a range of temperatures. Bloch-wave simulations are used to examine the effects that changes in different parameters have on the intensity in D-LACBED patterns, and atomic coordinates, thermal atomic displacement parameters and apparent occupancy are refined to achieve a good fit between simulation and experiment. The sensitivity of the technique to subtle changes in structure is demonstrated. Refined structures are in good agreement with previous determinations of Ca3Mn2O7 and show the decay of anti-phase oxygen octahedral tilts perpendicular to the c axis of the A21am unit cell with increasing temperature, as well as the robustness of oxygen octahedral tilts about the c axis up to ∼400°C. The technique samples only the zero-order Laue zone and is therefore insensitive to atom displacements along the electron-beam direction. For this reason it is not possible to distinguish between in-phase and anti-phase oxygen octahedral tilting about the c axis using the [110] data collected in this study.

A novel founder MSH2 deletion in Ethiopian Jews is mainly associated with early-onset colorectal cancer

Lynch syndrome is an inherited cancer predisposition syndrome caused by germline defects in any of the mismatch repair (MMR) genes. Diagnosis of carriers makes precision prevention, early detection, and tailored treatment possible. Herein we report a novel founder deletion of 18,758 bp, mediated by Alu repeats on both sides, detected in Ethiopian Jews. The deletion, which encompasses exon 9-10 of the MSH2 coding sequence, is associated mainly with early-onset MSH2/MSH6-deficient colorectal cancer (CRC) and liposarcoma. Testing of 35 members of 5 seemingly unrelated families of Ethiopian origin yielded 10/21 (48%) carriers, of whom 9 had CRC. Age at first tumor diagnosis ranged from 16 to 89 years. Carriers from the oldest generations were diagnosed after age 45 years (mean 57), and carriers from the younger generation were diagnosed before age 45 years (mean 30). Awareness of this founder deletion is important to improve patient diagnosis, institute surveillance from an early age, and refer patients for genetic counseling addressing the risk of bi-allelic constitutional MMR deficiency syndrome.

Prognostic role of myocardial work in patients with heart failure and reduced ejection fraction treated by sacubitril/valsartan

Funding Acknowledgements

Type of funding sources: None.

Background

the non-invasive assessment of myocardial work (MW) by pressure-strain loops analysis (PSL) is a relative new tool for the evaluation of myocardial performance. Sacubitril/Valsartan is a treatment for heart failure with reduced ejection fraction (HFrEF) which has a spectacular effect on the reduction of cardiovascular events (MACEs).

Purposes of this study were to evaluate 1) the short and medium term effect of Sacubitril/Valsartan treatment on MW parameters; 2) the prognostic value of MW in this specific group of patients.

Methods

79 patients with HFrEF (mean age: 66 ± 12 years; LV ejection fraction: 28 ± 9%) were prospectively included in the study and treated with Sacubitril/Valsartan. Echocardiographic examination was performed at baseline, and after 6- and 12-month of therapy with Sacubitril/Valsartan.

Results

Sacubitril/Valsartan significantly increased myocardial constructive work (CW) (1023 ± 449 vs 1424 ± 484 mmHg%, p &lt; 0.0001) and myocardial work efficiency (WE) [87 (78-90) vs 90 (86-95), p &lt; 0.0001]. During FU (2.6 ± 0.9 years), MACEs occurred in 13 (16%) patients. After correction for LV size, LVEF and WE, global myocardial constructive work (CW) was the only predictor of MACEs [HR 0.99 (0.99-1.00), p = 0.05]. (Table 1). A CW &lt; 910 mmHg (AUC = 0.81, p &lt; 0.0001, Figure 1, left panel) identified patients at particularly increase risk of MACEs [HR 11.09 (1.45-98.94), p = 0.002, log-rank test p &lt; 0.0001] (Figure 2, Right panel).

Conclusions

in patients with HFrEF who receive a comprehensive background beta-blocker and mineral-corticoid receptor antagonist therapy, Sacubitril/Valsartan induces a significant improvement of myocardial CW and WE. In this population, the estimation of CW before the initiation of Sacubitril/Valsartan therapy allows the prediction of MACEs.

Univariable analysis Multivariable analysis HR (95% CI) p-value HR (95% CI) p-value Age, per year 0.99 (0.95-1.04) 0.81 Ischemic cardiomyopathy 1.07 (0.36-3.21) 0.89 LVEDVi*, per ml/m2 1.01 (1.00-1.03) 0.03 LVESVi, per ml/m2 1.01 (1.00-1.03) 0.009 1.01 (0.99-1.02) 0.35 LVEF, per % 0.91 (0.85-0.98) 0.01 1.02 (0.93-1.12) 0.71 CW, per mmHg% 0.99 (0.99-1.00) 0.002 0.99 (0.99-1.00) 0.04 WE, per mmHg% 0.91 (0.86-0.96) 0.001 0.95 (0.88-1.02) 0.16 Predictors of MACEs at univariable and multivariable analysis Abstract Figure 1 A and B

Comparison of two methods to predict CRT-response

Funding Acknowledgements

Type of funding sources: Public hospital(s). Main funding source(s): Hospital university of Rennes INSERM - LTSI

Background

Non-invasive estimation of myocardial work by trans-thoracic echocardiography is a novel tool to analyze myocardial contraction efficiency during systole. Two methods are described, on using Left ventricular (LV) strain and a LV pressure estimation, and another with only LV strain integrals. The present study analyzes their utility in prediction of CRT-response.

Methods and results: 243 patients implanted by a CRT according to current recommendations were retrospectively included in hospital university of Rennes. All patients had a complete trans-thoracic echocardiography at implantation and at 6-moths follow-up. Responders were defined as having a 15% decrease in indexed LV end-systolic volume at follow-up compared to baseline. Baseline characteristics are described in table 1. 25.1% were non-responders. In this group, there were more men, more ischemic cardiomyopathies with more dilated LV. Strain signals ware analyzed only in the most informative loop, the apical 4 cavities. Myocardial work estimation with LV pressure estimation was previously described. The 3 different integral of strain signal were represented in figure 1. According to ROC curves, myocardial work (particularly wasted work in septal wall with AUC = 0.718 ± 0.04) estimated with LV pressure estimation is better than strain integrals to predict LV positive remodeling (best AUC 0.631 ± 0.040) after CRT-implantation.

Conclusion

Left ventricular pressure estimation give useful information on top of strain curves for prediction for CRT-response.

Table 1 Responders n = 182 Non-responders n = 61 Men (%) 109 (59.9%) 52 (85%) Ischemic cardiomyopathy (%) 42 (23.1%) 34 (55.7%) LVEF (%) 28 ± 6 28 ± 7 GLS (%) -9 ± 3 -7 ± 3 LVEDD (mm) 62 ± 8 67 ± 7 LVEDVi (ml/m2) 85 ± 34 88 ± 30 LVEF Left ventricular ejection fraction; GLS: global longitudinal strain; LVEDD: left ventricular end-diastolic diameter; LVEDVi: left ventricular end diastolic volume index Abstract Figure 1

Prospective validation of a non-invasive method to estimate myocardial work in aortic stenosis

Funding Acknowledgements

Type of funding sources: Public hospital(s). Main funding source(s): ANR - Maestro project

Background

Stratification of aortic stenosis patients remains challenging and robust indices are required. Myocardial work assessment is a new afterload independent alternative to evaluate left ventricular function. Although, this method was developed in patients with normal aortic valve. We previously developed an integrated cardiovascular system simulated by a computational model to estimate non-invasively myocardial work in aortic stenosis patients* (figure 1A). In the present study, we tested our model in a prospective population of AS patients.

Method and results

9 patients with severe AS (aortic valve area &lt; 1cm2) were included. A complete trans-thoracic echocardiography with a non-invasive blood pressure by brachial artery cuff were realized immediately before a left heart catheterization to have an invasive left ventricular pressure. Myocardial work is then calculated with non-invasive and invasive LV pressure combined to LV strain curves. For constructive and wasted work, root mean squared between invasive and estimated measures were respectively r2 = 0.92 and r2 = 0.94 (figure 1B)

Conclusion

The proposed model is efficient to estimate non-invasively myocardial work indices in AS-patients. These afterload independent indices could permit in future to better stratify this population. 

*Owashi KP, Hubert A and al. Model-based estimation of left ventricular pressure and myocardial work in aortic stenosis. PlosOne 2020. Mar 3;15(3):e0229609

Abstract Figure 1

Importance of systematic right ventricular assessment in cardiac resynchronization therapy candidates: a machine-learning approach

Funding Acknowledgements

Type of funding sources: None.

Background

Despite having all a systolic heart failure and broad QRS, patients proposed for cardiac resynchronization therapy (CRT) are highly heterogeneous and it remains extremely complicated to predict the impact of the device on left ventricular (LV) function and outcomes.

Objectives

We sought to evaluate the relative impact of clinical, electrocardiographic, and echocardiographic data on the left ventricular (LV) remodeling and prognosis of CRT-candidates by the application of machine learning (ML) approaches.

Methods

193 patients with systolic heart failure undergoing CRT according to current recommendations were prospectively included in this multicentre study. We used a combination of the Boruta algorithm and random forest methods to identify features predicting both CRT volumetric response and prognosis (Figure 1). The model performance was tested by the area under the receiver operating curve (AUC). We also applied the K-medoid method to identify clusters of phenotypically-similar patients.

Results

From 28 clinical, electrocardiographic, and echocardiographic-derived variables, 16 features were predictive of CRT-response; 11 features were predictive of prognosis.

Among the predictors of CRT-response, 7 variables (44%) pertained to right ventricular (RV) size or function. Tricuspid annular plane systolic excursion was the main feature associated with prognosis. The selected features were associated with a very good prediction of both CRT response (AUC 0.81, 95% CI: 0.74-0.87) and outcomes (AUC 0.84, 95% CI: 0.75-0.93) (Figure 1, Supervised Machine Learning Panel). An unsupervised ML approach allowed the identifications of two phenogroups of patients who differed significantly in clinical and parameters, biventricular size and RV function. The two phenogroups had significant different prognosis (HR 4.70, 95% CI: 2.1-10.0, p &lt; 0.0001; log –rank p &lt; 0.0001; Figure 1, Unsupervised Machine Learning Panel).

Conclusions

Machine learning can reliably identify clinical and echocardiographic features associated with CRT-response and prognosis. The evaluation of both RV-size and function parameters has pivotal importance for the risk stratification of CRT-candidates and should be systematically assessed in patients undergoing CRT.

Abstract Figure 1

Invasive Diagnosis of Coronary Functional Disorders Causing Angina Pectoris

Coronary vasomotion disorders represent a frequent cause of angina and/or dyspnoea in patients with non-obstructed coronary arteries. The highly sophisticated interplay of vasodilatation and vasoconstriction can be assessed in an interventional diagnostic procedure. Established parameters characterising adequate vasodilatation are coronary blood flow at rest, and, after drug-induced vasodilation, coronary flow reserve, and microvascular resistance (hyperaemic microvascular resistance, index of microcirculatory resistance). An increased vasoconstrictive potential is diagnosed by provocation testing with acetylcholine or ergonovine. This enables a diagnosis of coronary epicardial and/or microvascular spasm. Ischaemia associated with microvascular spasm can be confirmed by ischaemic ECG changes and the measurement of lactate concentrations in the coronary sinus. Although interventional diagnostic procedures are helpful for determining the mechanism of the angina, which may be the key to successful medical treatment, they are still neither widely accepted nor applied in many medical centres. This article summarises currently well-established invasive methods for the diagnosis of coronary functional disorders causing angina pectoris.

Prognostic utility of the assessment of diastolic function in patients undergoing cardiac resynchronization therapy

Conflicting data exist about the relationship between cardiac resynchronization therapy (CRT) and diastolic function. Aims of the study are to assess diastolic patterns in patients undergoing CRT according to the 2016 recommendations of the American Society of Echocardiography/European Association of Cardiovascular Imaging and to evaluate the prognostic value of diastolic dysfunction (DD) in CRT candidates. METHODS AND RESULTS: One-hundred ninety-three patients (age: 67 ± 11 years, QRS width: 167 ± 21 ms) were included in this multicentre prospective study. Mitral filling pattern, mitral tissue Doppler velocity, tricuspid regurgitation velocity, and indexed left atrial volume were used to classify DD from grade I to III. CRT-response, defined as a reduction of left ventricular (LV) end-systolic volume > 15% at 6-month follow-up (FU), occurred in 132 (68%) patients. The primary endpoint was a composite of heart transplantation, LV assisted device implantation, or all-cause death during FU and occurred in 29 (15%) patients. CRT was associated with a degradation of DD in non-responders. At multivariable analysis corrected for clinical variables, QRS duration, mitral regurgitation, CRT-response and LV dyssynchrony, grade I DD was associated with a better outcome (HR 0.37, 95% CI: 0.14-0.96). Non-responders with grade II-III DD had the worse prognosis (HR 4.36, 95%CI: 2.10-9.06). CONCLUSIONS: The evaluation of DD in CRT candidates allows the prognostic stratification of patients, independently from CRT-response.

Non-invasive estimation of myocardial work in aortic stenosis from modelling approach

Background

The noninvasive assessment of myocardial work by pressure-strain loops (PSL) analysis is a recently introduced tool to estimate myocardial performance. PSL analysis cannot be applied to patients having an obstacle to LV ejection, as in the case of aortic stenosis (AS), because of the difficulty to estimate left ventricular (LV) pressure.

The purpose of this work is to propose a non-invasive model-based estimation of the left ventricular pressure curve in AS patients in order to evaluate myocardial work indices.

Methods

Twelve patients with moderate-to-severe AS underwent cardiac catheterization to acquire the LV pressure (Pexp-LV). All patients underwent a standard trans-thoracic echocardiography to extract regional myocardial strain curves and estimate the aortic valve area (AVA). Systolic and diastolic arterial pressures were also measured. The proposed cardiovascular system (CVS) model is composed of four main coupled sub-models simulating: i) cardiac electrical activities, ii) cardiac cavity, iii) the systemic and pulmonary circulation, and iv) cardiac valves (Figure 1, upper panel). A 2-step parameter identification strategy, based evolutionary algorithms, was implemented to learn LV parameters from Pexp-LV and to estimate patient-specific model-based LV pressure curves (Pmodel-LV) starting from parameters obtained from non-invasive hemodynamics. Global myocardial constructive work (GCW) and myocardial wasted work (GWW) were calculated using Pexp-LV and Pmodel-LV.

Results

A close match was observed between Pexp-LV and Pmodel-LV, with a mean total relative error of 12.27% (range 5.9% to 17.40%). When considering GCW and GWW, global correlation was equal to 0.92 (p&lt;0.0001). In BA analysis, mean bias was −2.9 mmHg.%, which corresponds to relative bias equal to 0.11% with respect to the mean value of work indices (Figure 1, lower panel).

Conclusions

A model-based approach can be used to estimate LV pressure and myocardial work indices in patients with AS, and be provide a promising tool for the assessment of myocardial performance in patients with AS

Funding Acknowledgement

Type of funding source: None

Mechanisms of angina in patients with biopsy-proven viral myocarditis: insights from intracoronary acetylcholine testing

Background

Patients with myocarditis often present with angina pectoris despite unobstructed coronary arteries. The underlying pathophysiological mechanism of angina in these patients remains to be elucidated. Coronary artery spasm is a well-known cause of angina in patients with unobstructed coronary arteries. In this study, we sought to assess the frequency of coronary vasomotor disorders in patients with biopsy-proven viral myocarditis.

Methods

In total, 700 consecutive patients who underwent endomyocardial biopsy for suspected myocarditis between 2008 and 2018 were retrospectively screened. Of these patients, viral myocarditis was confirmed in 303 patients defined as histological/immunohistological evidence of myocardial inflammation and presence of viral genome confirmed by PCR. Of these patients, 34 patients had angina despite unobstructed coronary arteries and underwent intracoronary acetylcholine (ACh) provocation testing in search of coronary spasm. Epicardial spasm was defined as acetylcholine-induced reproduction of the patient's symptoms associated with ischemic ECG changes and &gt;90% epicardial vasoconstriction. Microvascular spasm was defined as symptom reproduction and ECG changes in the absence of significant epicardial vasoconstriction.

Results

Patients were 49±16 years old, 62% were male and left ventricular ejection fraction was 54±16%. Most frequent viruses were parvovirus B19 (PVB19, 59%) and human herpes virus 6 (HHV6, 26%), 2 patients had combined PVB19/HHV6 infection and 3 patients other herpesviruses (CMV, EBV, VZV). Epicardial spasm was observed in 10 patients (29%) during ACh testing and microvascular spasm was found in 11 patients (32%). The rate of coronary spasm (epicardial and microvascular) was higher in the PVB19 subgroup compared to HHV6 (80% vs. 33%, p=0.031). In particular, there was a higher prevalence of microvascular spasm in PVB19 compared to HHV6 (45% vs. 0%, p=0.018).

Conclusion

We observed a high prevalence of microvascular and epicardial spasm in patients with biopsy-proven viral myocarditis suggesting coronary spasm as a potential underlying mechanism for angina in these patients. Microvascular spasm was most often observed in patients with PVB19-associated myocarditis.

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): Robert-Bosch-Stiftung; Berthold-Leibinger-Stiftung

Prognostic role of myocardial work in patients with heart failure and reduced ejection fraction treated by sacubitril/valsartan

Background

The non-invasive assessment of myocardial work (MW) by pressure-strain loops analysis (PSL) is a relative new tool for the evaluation of myocardial performance. Sacubitril/Valsartan is a treatment for heart failure with reduced ejection fraction (HFrEF) which has a spectacular effect on the reduction of cardiovascular events (MACEs).

Purposes of this study were to evaluate 1) the short and medium term effect of Sacubitril/Valsartan treatment on MW parameters; 2) the prognostic value of MW in this specific group of patients.

Methods

79 patients with HFrEF (mean age: 66±12 years; LV ejection fraction: 28±9%) were prospectively included in the study and treated with Sacubitril/Valsartan. Echocardiographic examination was performed at baseline, and after 6- and 12-month of therapy with Sacubitril/Valsartan.

Results

Sacubitril/Valsartan significantly increased global myocardial constructive work (CW) (1023±449 vs 1424±484 mmHg%, p&lt;0.0001) and myocardial work efficiency (WE) [87 (78–90) vs 90 (86–95), p&lt;0.0001]. During FU (2.6±0.9 years), MACEs occurred in 13 (16%) patients. After correction for LV size, LVEF and WE, CW was the only predictor of MACEs (Table 1). A CW&lt;910 mmHg (AUC=0.81, p&lt;0.0001, Figure 1A) identified patients at particularly increase risk of MACEs [HR 11.09 (1.45–98.94), p=0.002, log-rank test p&lt;0.0001] (Figure 1 B).

Conclusions

In patients with HFrEF who receive a comprehensive background beta-blocker and mineral-corticoid receptor antagonist therapy, Sacubitril/Valsartan induces a significant improvement of myocardial CW and WE. In this population, the estimation of CW before the initiation of Sacubitril/Valsartan therapy allows the prediction of MACEs.

Funding Acknowledgement

Type of funding source: None

Model-based analysis of myocardial strain in left bundle branch block patients

Background

Although patients with typical left bundle branch block (LBBB) show greater efficacy of cardiac resynchronization therapy (CRT), there is a wide range of responses to CRT with a subset of patients showing little or no improvement. Recently, it has been shown that combination of echo-based parameters of LV dyssynchrony and QRS duration helped to improve the prediction of the response to CRT. However, the interpretation of features extracted from echocardiography could be difficult due the complexity of mechanisms involved in cardiac contraction. Computational modelling could help to improve the interpretation of myocardial strains in LBBB patients before implantation.

Purpose

Purpose of the study is to propose a patient-specific model-based approach in order to assist the analysis of myocardial strains and to improve the interpretability of echo-based parameters.

Methods

The proposed model of the cardiovascular system integrates four main sub-models: 1) cardiac electrical system, 2) right and left atrium, 3) multi-segment right and left ventricles and 4) systemic and pulmonary circulations. Patient-specific simulations of myocardial strains were obtained by coupling the computational model and the clinical data to a parameter identification algorithm (Figure 1, upper panel). The proposed approach was evaluated on data obtained from 10 LBBB patients, including ischaemic (n=5) and non-ischaemic (n=5) cardiomyopathy. The localisation of scar was determined by cardiac MRI. Bull's-eye representations of the electrical activation time and contractility levels were analysed.

Results

The comparison between simulated and experimental strains for the 10 subjects reflects a satisfying adaptation of the model to different strain morphologies. The mean errors between real and synthesized signals are equal to 3.72±0.91. The lower panel of Figure 1 presents simulated (black line) and experimental (red line) myocardial strain signals for selected LBBB patients with a lateral ischaemia, anterior ischaemia and non-ischaemia. The bull's-eye representations of electrical activation delay and contractility levels, estimated from the model-based approach, for ischemic and non-ischemic LBBB is included in the figure. Contractility bull's-eye results allow ischaemic and non-ischaemic cases distinction, where low levels of contractility could be associated with damaged tissues.

Conclusion

Identified parameters show significant electrical conduction, mechanical activation delays for the LBBB patient. Hypocontractile myocardial segments were successfully localized from the model-based approach in both ischemic and non-ischemic patients.

Funding Acknowledgement

Type of funding source: None

Better diastolic function in CRT candidates is associated with improved survival after CRT implantation

Background

The relationship between diastolic dysfunction (DD) and outcome after CRT is debated.

Purpose

Purpose of this study was to evaluate the role of DD in predicting all-cause mortality in heart failure patients undergoing CRT.

Methods

One-hundred ninety-three patients (age: 67±11 years, QRS width: 167±21 ms, LVEF 28±8%) were included in this multicentre prospective study. Mitral filling pattern, mitral tissue Doppler velocity, tricuspid regurgitation velocity, and indexed left atrial volume were used to classify DD from grade I to III according to the 2016 recommendations of the American Society of Echocardiography/European Association of Cardiovascular Imaging. A reduction of LV end-systolic volume &gt;15% at 6-month follow-up (FU) identified CRT-responders and was observed in 132 (68%) patients.

Results

During a median 35 months FU, 29 (15%) patients died. Through multivariable analysis, coronary artery disease, NYHA functional class and grade I DD were shown to be independent predictors of prognosis (Table 1). Grade I DD was associated with a longer survival rate in both responders and non responders (Figure 1). Non responders with grade II-III DD had the worse outcome (HR 12.5 [3.56–44.04], p&lt;0.0001).

Conclusions

Better diastolic function at baseline is associated with an improved survival after CRT implantation, independently of CRT-response.

Funding Acknowledgement

Type of funding source: None

New expectations for diastolic function assessment in TTE based on a semi-automated computing of strain-volume loops

Background

Early diagnosis of heart failure with preserved ejection fraction (HFpEF) by determination of diastolic dysfunction is challenging. Strain-volume loop (SVL) is a new tool to analyze left ventricular function.

Purpose

We propose a new semi-automated method to calculate SVL area and explore the added value of this index for diastolic function assessment.

Methods

50 patients (25 amyloidosis, 25 HFpEF) were included in the study and compared with 25 healthy control subjects. All patients underwent standard echocardiography. SVL area were also assessed.

Results

Left ventricular ejection fraction was preserved and similar between groups. Classical indices of diastolic function were pathological in HFpEF and amyloidosis groups with greater left atrial volume index, greater mitral average E/e' ratio, faster tricuspid regurgitation (p&lt;0.0001 compared with controls). SVL analysis demonstrated a significant difference of the global area between groups, with the smaller area in amyloidosis group, the greater in controls and a mid-range value in HFpEF group (37 vs 120 vs 72 ml.%, respectively, p&lt;0.0001) (Table 1). Applying a Linear Discriminant Analysis (LDA) classifier, results show a mean area under the curve (AUC) of 0.89 for the comparison between HFpEF and amyloidosis groups (Figure 1).

Conclusion

Strain-volume loops area is efficient to identify patients with a diastolic dysfunction. This new semi-automated tool is very promising for future development of automated diagnosis with machine-learning algorithms.

Figure 1

Funding Acknowledgement

Type of funding source: None

Safety assessment and results of coronary spasm provocation testing in patients with myocardial infarction with unobstructed coronary arteries compared to patients with stable angina and unobstructed coronary arteries

BACKGROUND

Coronary spasm is an established cause for myocardial infarction with unobstructed coronary arteries, and can be diagnosed using intracoronary acetylcholine testing. However, it has been questioned whether such testing is feasible and safe in the acute phase. The aim of this study was to assess the frequency of coronary spasm and the safety of the acetylcholine test in patients with myocardial infarction with unobstructed coronary arteries compared to patients with stable angina and unobstructed coronaries.

METHODS

One hundred and eighty selected patients (52% women, mean age 62±13 years) with either myocardial infarction with unobstructed coronary arteries (n=80) or stable angina and unobstructed coronaries (n=100) were enrolled from 2007-2018. All patients underwent the acetylcholine test according to a standardised protocol immediately after diagnostic angiography. Apart from assessment of clinical, demographic and risk factor data, side effects and complications during the acetylcholine test were recorded.

RESULTS

Overall, epicardial spasm was found in 26% with a higher prevalence among the myocardial infarction with unobstructed coronary arteries compared to the stable angina patients (35% vs 19%, p=0.017). Microvascular spasm was found in 42% with a higher prevalence among the stable patients compared to the myocardial infarction with unobstructed coronary arteries cohort (53% vs 29%, p=0.0014). There were no statistically significant differences in the rate of side effects (16% vs 14%, p=0.674) or complications (1% vs 2.5%, p=0.438) between the two groups. None of the patients experienced irreversible complications.

CONCLUSION

Coronary spasm is a frequent cause for myocardial infarction with unobstructed coronary arteries. Spasm provocation testing using acetylcholine is feasible in such patients in the acute phase. The complication rate during acetylcholine testing in myocardial infarction with unobstructed coronary arteries patients is low and comparable to patients with stable angina.

Coronary Artery Spasm: The Interplay Between Endothelial Dysfunction and Vascular Smooth Muscle Cell Hyperreactivity

Patients with angina pectoris, the cardinal symptom of myocardial ischaemia, yet without significant flow-limiting epicardial artery stenosis represent a diagnostic and therapeutic challenge. Coronary artery spasm (CAS) is an established cause for anginal chest pain in patients with angiographically unobstructed coronary arteries. CAS may occur at the epicardial level and/or in the microvasculature. Although the underlying pathophysiological mechanisms of CAS are still largely unclear, endothelial dysfunction and vascular smooth muscle cell (VSMC) hyperreactivity seem to be involved as major players, although their contribution to induce CAS is still seen as controversial. This article will look at the role and possible mechanistic interplay between an impaired endothelial and VSMC function in the pathogenesis of CAS.

Diagnosis of coronary microvascular dysfunction in the clinic

The coronary microcirculation plays a pivotal role in the regulation of coronary blood flow and cardiac metabolism. It can adapt to acute and chronic pathologic conditions such as coronary thrombosis or long-standing hypertension. Due to the fact that the coronary microcirculation cannot be visualized in human beings in vivo, its assessment remains challenging. Thus, the clinical importance of the coronary microcirculation is still often underestimated or even neglected. Depending on the clinical condition of the respective patient, several non-invasive (e.g. transthoracic Doppler-echocardiography assessing coronary flow velocity reserve, cardiac magnetic resonance imaging, positron emission tomography) and invasive methods (e.g. assessment of coronary flow reserve (CFR) and microvascular resistance (MVR) using adenosine, microvascular coronary spasm with acetylcholine) have been established for the assessment of coronary microvascular function. Individual patient characteristics, but certainly also local availability, methodical expertise and costs will influence which methods are being used for the diagnostic work-up (non-invasive and/or invasive assessment) in a patient with recurrent symptoms and suspected coronary microvascular dysfunction. Recently, the combined invasive assessment of coronary vasoconstrictor as well as vasodilator abnormalities has been titled interventional diagnostic procedure (IDP). It involves intracoronary acetylcholine testing for the detection of coronary spasm as well as CFR and MVR assessment in response to adenosine using a dedicated wire. Currently, the IDP represents the most comprehensive coronary vasomotor assessment. Studies using the IDP to better characterize the endotypes observed will hopefully facilitate development of tailored and effective treatments.

Lysed Erythrocyte Membranes Promote Vascular Calcification

BACKGROUND

Intraplaque hemorrhage promotes atherosclerosis progression, and erythrocytes may contribute to this process. In this study we examined the effects of red blood cells on smooth muscle cell mineralization and vascular calcification and the possible mechanisms involved.

METHODS

Erythrocytes were isolated from human and murine whole blood. Intact and lysed erythrocytes and their membrane fraction or specific erythrocyte components were examined in vitro using diverse calcification assays, ex vivo by using the murine aortic ring calcification model, and in vivo after murine erythrocyte membrane injection into neointimal lesions of hypercholesterolemic apolipoprotein E-deficient mice. Vascular tissues (aortic valves, atherosclerotic carotid artery specimens, abdominal aortic aneurysms) were obtained from patients undergoing surgery.

RESULTS

The membrane fraction of lysed, but not intact human erythrocytes promoted mineralization of human arterial smooth muscle cells in culture, as shown by Alizarin red and van Kossa stain and increased alkaline phosphatase activity, and by increased expression of osteoblast-specific transcription factors (eg, runt-related transcription factor 2, osterix) and differentiation markers (eg, osteopontin, osteocalcin, and osterix). Erythrocyte membranes dose-dependently enhanced calcification in murine aortic rings, and extravasated CD235a-positive erythrocytes or Perl iron-positive signals colocalized with calcified areas or osteoblast-like cells in human vascular lesions. Mechanistically, the osteoinductive activity of lysed erythrocytes was localized to their membrane fraction, did not involve membrane lipids, heme, or iron, and was enhanced after removal of the nitric oxide (NO) scavenger hemoglobin. Lysed erythrocyte membranes enhanced calcification to a similar extent as the NO donor diethylenetriamine-NO, and their osteoinductive effects could be further augmented by arginase-1 inhibition (indirectly increasing NO bioavailability). However, the osteoinductive effects of erythrocyte membranes were reduced in human arterial smooth muscle cells treated with the NO scavenger 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide or following inhibition of NO synthase or the NO receptor soluble guanylate cyclase. Erythrocytes isolated from endothelial NO synthase-deficient mice exhibited a reduced potency to promote calcification in the aortic ring assay and after injection into murine vascular lesions.

CONCLUSIONS

Our findings in cells, genetically modified mice, and human vascular specimens suggest that intraplaque hemorrhage with erythrocyte extravasation and lysis promotes osteoblastic differentiation of smooth muscle cells and vascular lesion calcification, and also support a role for erythrocyte-derived NO.

Coronary Microvascular Spasm as the Underlying Cause of the Angiographic Slow Flow Phenomenon

Slow coronary flow is frequently seen during angiography in patients with angina and unobstructed coronary arteries. However, the pathophysiology of this finding remains largely unclear. We report a case of a 52-year-old woman with slow coronary flow caused by acetylcholine-induced microvascular spasm, as confirmed by intracoronary flow measurements. (Level of Difficulty: Beginner.).

101 Semi-automated volume-strain loops: a new tool in TTE to assess diastolic dysfunction

AIM

This work aims to evaluate a novel semi-automatic tool for the assessment of volume-strain loops by transthoracic echocardiography (TTE).

METHOD

17 patients with proved cardiac amyloidosis and 18 patients with heart failure with preserved ejection fraction (HFpEF) were compared to 19 controls, from a local database. All TTE were performed using Vivid E95 ultrasound system (General Electrics Healthcare, Horten, Norway). The complete method includes several steps: 1) extraction of LV strain full traces from apical 4 and 2 cavities views, 2) estimation of LV volume from these two traces by spline interpolations, 3) resampling of LV strain curves, determined for the same cardiac beat, (in apical 4-, 2- and 3- cavities views) as a function of pre-defined percentage increments of LV-volume and 4) calculation of the LV volume-strain loop area. (Figure 1, panel A)

RESULTS (Table 1): LVEF was similar between all groups whereas global longitudinal strain was significantly lower in amyloidosis group than controls (-14.4 vs -20.5%; p &lt; 0.001). HFpEF and amyloidosis groups had a worse diastolic function than controls with a greater left atrial volume index , a faster tricuspid regurgitation, a greater E/e’ ratio with a p &lt; 0.001 for all these indices. Simultaneously, the global area of volume-strain loop was significantly lower in HFpEF and amyloidosis group than controls (72 vs 36 vs 120.0 %.mL, respectively, p &lt; 0.0001) with an intermediate profile of HFpEF(Figure 1, panel B, HFpEF in green). This area was better correlated with mean e’ (r = 0.650, p &lt; 0.001) than all other indices.

CONCLUSION

LV volume-strain loop area appears a very promising new tool to assess semi-automatically diastolic function.

Main echocardiographic results Controls n = 19 HFpEF n = 18 Amyloidosis n = 17 p-value LVEDV (mL) 105 ± 15 103 ± 30 95 ± 93 0.476 LVEF (%) 65 ± 5 62 ± 7 62 ± 7 0.196 GLS (%) -20.5 ± 1.8 -18.4 ± 4.3 -14.4 ± 3.8 &lt;0.0001 LAVi (ml.m-2) 22 ± 5 51 ± 14 51 ± 22 &lt;0.0001 E/A ratio 2.1 ± 0.4 1.2 ± 0.7 1.7 ± 1.0 0.005 Mitral E/Ea average 5.9 ± 1.4 13.7 ± 5.8 17.3 ± 5.4 &lt;0.0001 Vmax TR (m/s) 2.0 ± 0.3 3.1 ± 0.4 2.7 ± 0.5 &lt;0.0001 V-S loop area (ml.%) 120 ± 54 72 ± 45 37 ± 21 &lt;0.0001

Abstract 101 Figure 1

P1779 Myocardial work is a predictor of exercise tolerance in patients with dilated cardiomyopathy and left ventricular dyssynchrony

Background

the assessment of myocardial work (MW) by pressure-strain loops is a recently introduced tool for the assessment of myocardial performance. Aim of the present study is to evaluate the relationship between myocardial work and exercise tolerance in patients with dilated cardiomyopathy (DCM)

Methods

51 patients with DCM (mean age 57 ± 13 years, left entricular ejection fraction : 32 ± 9%) underwent cardiopulmonary exercise test (CPET) to assess exercise performance. Trans-thoracic echocardiography (TTE) was performed CPET. The following indices of myocardial work (MW) were measured regionally and globally: constructive work (CW), wasted work (WW), and work efficiency (WE). Left ventricular (LV) dyssynchrony (DYS) was defined by the presence of septal flash or apical rocking at TTE.

Results

LV-DYS was observed in 16 (31%) patients and associated with lower LV ejection fraction (LVEF), GLS, global and septal WE, and higher global and septal WW (Table 1). In patients with LV-DYS, septal WE was the only predictor of exercise peak VO2max at multivariable analysis (Figure 1), whereas LVEF (β=0.47, p = 0.05) and age (β=-0.42, 47, p= 0.04) were predictors of exercise capacity in patients without LV-DYS.

Conclusions

In patients with DCM, LV-DYS is associated with an heterogeneous distribution of myocardial work. Septal WE is the best predictor of exercise performance in these patients.

Table 1 All n = 51 No-dyssynchrony n = 35 (69%) LV-Dyssynchrony n = 16 (31%) p-value LVEF, % 32 ± 9 34 ± 10 28 ± 7 0.04 GLS, % -12 ± 3 -13 ± 3 -10 ± 3 0.001 GCW, mmHg% 1325 ± 398 1342 ± 354 1287 ± 491 0.65 GWW, mmHg% 201 ± 147 154 ± 95 304 ±191 &lt;0.0001 GWE, % 85 ± 9 88 ± 7 78 ±10 &lt;0.0001 CWsept, mmHg% 1172 ± 459 1274 ± 398 949 ± 516 0.017 CWlat, mmHg% 1518 471 1472 ± 386 1620 ± 622 0.30 WWsept, mmHg% 283 ± 275 174 ± 98 522 ±376 &lt;0.0001 WWlat, mmHg% 135 ± 88 117 ± 81 176 ± 92 0.02 WEsept, % 78 ± 16 84 ± 9 62± 18* &lt;0.0001 WElat, % 90 ± 7 91 ± 7 88 ± 7 0.16

Abstract P1779 Figure.

539 Optimized multiparametric analysis of cardiac dyssynchrony: machine learning and prediction of response to cardiac resynchronization therapy based of the apical 4-chamber view

Conclusion

The high number of important features indicate the relevance of the 4-chamber as unique view for applying machine learning approaches on strain curves. Optimizing selection of patients for CRT should be possible just on the dataset coming from one apical 4-chamber view.

Abstract 539 Figure. fig1

557 Left ventricular diastolic function is a predictor of volumetric response to cardiac resynchronization therapy

Background

Conflicting data exist about the effects of cardiac resynchronization therapy (CRT) on diastolic function (DF). Aims of the study are: 1) to assess diastolic patterns in patients undergoing CRT; 2) to evaluate the role of DF in predicting CRT-response.

Methods

193 patients (age: 67 ± 11 ms, QRS width: 167 ± 21 ms, LVEF 28 ± 8%) were prospectively included in this multicentric study. 2D-standard echocardiography was performed before CRT and at 6-month follow-up (FU). DF was assessed according to recommendations from grade I to III. In case of data in the "grey zone", DF was defined as "indeterminate". A reduction of left ventricular (LV) end-systolic volume &gt;15% at FU identified CRT-responders (CRT-R).

Results

At 6-month FU, 132 patients (68%) were CRT-R. Figure 1 shows DF parameters in the overall population, CRT-R, and CRT-non responders (CRT-NR) before and after CRT. At multivariable analysis, grade I diastolic dysfunction at baseline was a significant independent predictor of CRT response (OR 3.02, p = 0.001) (Table 1). The addition of grade I diastolic dysfunction to a model including clinical (sex, NYHA class, ischemic cardiomyopathy) and echocardiographic parameters (LV size), significantly increase the model power for the prediction of CRT-response (χ2: 29 vs 44, p = 0.001).

Conclusions

Before CRT, DF parameters are significantly altered in CRT-NR with respect to CRT-R. Moreover, CRT-NR experience a significant deterioration of DF after CRT. In our population, grade I diastolic function at baseline was a significant independent predictor of positive response to CRT.

Table 1 Univariable analysis Multivariable analysis Age 1.01 (0.99-1.05) 0.25 Males 0.36 (0.17-0.76) 0.008 0.57 (0.22-1.47) 0.25 CAD 0.21 (0.11-0.40) &lt;0.001 0.31 (0.15-0.65) 0.002 NYHA 0.52 (0.31-0.88) 0.01 0.57 (0.22-1.47) 0.25 QRS 1.01 (0.99-1.02) 0.44 LVEDV 0.99 (0.99-1.00) 0.003 0.98 (0.97-1.01) 0.18 LVESV 0.99 (0.98-0.99) 0.005 1.01 (0.99-1.03) 0.28 LVEF 1.00 (0.97-1.05) 0.63 Grade I DD 4.13 (2.16-7.91) &lt;0.0001 3.02 (1.26-7.23) 0.001 Grade II DD 0.57 (0.40-0.80) 0.001 0.87 (0.35-2.19) 0.79 Grade III DD 0.76 (0.58-1.02) 0.06

Abstract 557 Figure.

424 Left ventricular function after correction of a proportionate mitral regurgitation: impact of the clipping approach

Method and results

Thirty-seven patients with severe secondary MR treated by PMVR were included and compared (according to indices of LV myocardial function) to nineteen patients with treated by OMT. Both groups were clinically comparable. At 6-month follow-up, only LV constructive work improve significantly in both groups (977 vs 1101 mmHg.%, p =0,003, 967 vs 1110 mmHg.%, p = 0,002 for PMVR and OMT groups, respectively) whereas left ventricular (LV) end-systolic volume index, LV ejection fraction and global longitudinal strain were not different. Compared to MITRA-FR and COAPT studies, our population had a proportionate MR (blue point in Figure 1, panel A). Figure 1-panel B demonstrate that only five patients of PMVR group had disproportionate MR (red points). Interestingly, these patients hadn’t any major event during 6 months FU.

Conclusion

Echocardiographic characteristics at 6-month follow-up are not different when compare PMVR and OMT for HF- patients with a severe proportionate secondary MR.

Main echocardiographic characteristics PMVR OMT Inclusion 6-month p Inclusion 6-month p NYHA 2.6 ± 0.6* 1.8 ± 0.7* &lt;0.0001 2.3 ± 0.5* 2.2 ± 0.4* 0.43 LVESVi(ml.m-2) 76 ± 36 75 ± 35 0.6 94 ± 32 90 ± 31 0.35 LVEF (%) 33 ± 6 33 ± 13 0.78 30 ± 8 31 ± 8 0.53 GLS (%) -9.8 ± 4 -9.9 ± 3.9 0.84 -10.0 ± 4 -10.3 ± 3.3 0.62 MR grade 3.4 ± 0.5 1.3 ± 1.0* &lt;0.0001 3.5 ± 0.5 2.8 ± 1.1* 0.007 Global work index (mmHg.%) 831 ± 370 933 ± 406 0.07 875 ± 314 939 ± 304 0.14 Constructive work (mmHg.%) 977 ± 366 1101 ± 404 0.003 967 ± 290 1110 ± 349 0.002 *symbols denote p &lt; 0.05 between both groups

Abstract 424 Figure.

Endothelial Leptin Receptor Deletion Promotes Cardiac Autophagy and Angiogenesis Following Pressure Overload by Suppressing Akt/mTOR Signaling

BACKGROUND

Cardiac remodeling is modulated by overnutrition or starvation. The adipokine leptin mediates energy balance between adipose tissue and brain. Leptin and its receptors are expressed in the heart.

METHODS AND RESULTS

To examine the importance of endothelial leptin signaling in cardiac hypertrophy, transverse aortic constriction was used in mice with inducible endothelium-specific deletion of leptin receptors (End.LepR-KO) or littermate controls (End.LepR-WT). End.LepR-KO was associated with improved left ventricular function (fractional shortening, 28.4% versus 18.8%; P=0.0114), reduced left ventricular dilation (end-systolic inner left ventricular diameter, 3.59 versus 4.08 mm; P=0.0188) and lower heart weight (133 versus 173 mg; P<0.0001) 20 weeks after transverse aortic constriction. Histology and quantitative polymerase chain reaction analysis confirmed reduced cardiomyocyte hypertrophy. STAT3 (signal transducer and activator of transcription) activation was reduced, and Akt (protein kinase B) and mTOR (mammalian target of rapamycin) phosphorylation after transverse aortic constriction were blunted in End.LepR-KO hearts. Elevated LC3 (microtubule associated protein 1 light chain 3)-I/-II conversion ( P=0.0041) and increased (LC3II-positive) endothelial cells ( P=0.0042) in banded hearts of End.LepR-KO mice suggested improved cardiac angiogenesis because of activated autophagy. Microscopy confirmed autophagosome accumulation after genetic or small interfering RNA-mediated LepR downregulation. Enhanced sprouting angiogenesis was observed in endothelial cells ( P<0.0001) and aortic rings ( P=0.0060) from End.LepR-KO mice, and murine and human endothelial sprouting angiogenesis was reduced after mTOR inhibition using rapamycin or autophagy inhibition using 3-methyladenine. Banded End.LepR-KO mouse hearts exhibited less apoptosis ( P=0.0218), inflammation ( P=0.0251), and fibrosis ( P=0.0256). Reduced endothelial autophagy was also observed in myocardial biopsies of heart failure patients with cardiac fibrosis.

CONCLUSIONS

Our findings suggest that endothelial leptin signaling contributes to cardiac fibrosis and functional deterioration by suppressing endothelial autophagy and promoting endothelial dysfunction in a chronic pressure overload model.

P1486Semi-automated volume-strain loops: a new tool in TTE to assess diastolic dysfunction

Aim

This work aims to evaluate a novel semi-automatic tool for the assessment of volume-strain loops by transthoracic echocardiography (TTE). The proposed method was evaluated on a typical model of left ventricular (LV) diastolic dysfunction: the cardiac amyloidosis.

Method

18 patients with proved cardiac amyloidosis were compared to 19 controls, from a local database. All TTE were performed using Vivid E9 or E95 ultrasound system. The complete method includes several steps: 1) extraction of LV strain full traces from apical 4 and 2 cavities views, 2) estimation of LV volume from these two traces by spline interpolations, 3) resampling of LV strain curves, determined for the same cardiac beat, (in apical 4-, 2- and 3- cavities views) as a function of pre-defined percentage increments of LV-volume and 4) calculation of the LV volume-strain loop area. (Figure 1, panel B)

Results

(Table 1): LVEF was similar between both groups whereas global longitudinal strain was significantly lower in amyloidosis group (−14.4 vs −20.5%; p<0.001). Amyloidosis group had a worse diastolic function with a greater left atrial volume index (51 vs 22ml/m2), a faster tricuspid regurgitation (2.7 vs 2.0 m/s), a greater E/e' ratio (17.3 vs 5.9) with a p<0.001 for all these indices. Simultaneously, the global area of volume-strain loop was significantly lower in amyloidosis group (36.5 vs 120.0%.mL). This area was better correlated with mean e' with r=0.734 (p<0.001) than all other indices (Figure 1, panel A).

Table 1 Amyloidosis (N=18) Controls (N=19) p Global strain-volume loop area (%.mL) 36.5±21.3 120.0±54.2 <0.001 Global longitudinal strain (%) −14.4±3.8 −20.5±1.8 <0.001 Left ventricular ejection fraction (%) 62±7 65±5 0.08 Left atrial volume index (ml/m2) 51±22 22±5 <0.001 E/A 1.72±0.97 2.07±0.45 0.17 Mean e' 5.5±1.3 14.4±2.8 <0.001 Mean E/e' 17.3±5.4 5.9±1.4 <0.001 Tricuspid regurgitation velocity (m/s) 2.7±3.8 2.0±0.3 <0.001

Figure 1

Conclusion

LV volume-strain loop area appears a very promising new tool to assess semi-automatically diastolic function. Future applications will concern the integration of LV volume-strain loop area as novel feature in machine-learning approach.

The natural history of classic galactosemia: lessons from the GalNet registry

BACKGROUND

Classic galactosemia is a rare inborn error of carbohydrate metabolism, caused by a severe deficiency of the enzyme galactose-1-phosphate uridylyltransferase (GALT). A galactose-restricted diet has proven to be very effective to treat the neonatal life-threatening manifestations and has been the cornerstone of treatment for this severe disease. However, burdensome complications occur despite a lifelong diet. For rare diseases, a patient disease specific registry is fundamental to monitor the lifespan pathology and to evaluate the safety and efficacy of potential therapies. In 2014, the international Galactosemias Network (GalNet) developed a web-based patient registry for this disease, the GalNet Registry. The aim was to delineate the natural history of classic galactosemia based on a large dataset of patients.

METHODS

Observational data derived from 15 countries and 32 centers including 509 patients were acquired between December 2014 and July 2018.

RESULTS

Most affected patients experienced neonatal manifestations (79.8%) and despite following a diet developed brain impairments (85.0%), primary ovarian insufficiency (79.7%) and a diminished bone mineral density (26.5%). Newborn screening, age at onset of dietary treatment, strictness of the galactose-restricted diet, p.Gln188Arg mutation and GALT enzyme activity influenced the clinical picture. Detection by newborn screening and commencement of diet in the first week of life were associated with a more favorable outcome. A homozygous p.Gln188Arg mutation, GALT enzyme activity of ≤ 1% and strict galactose restriction were associated with a less favorable outcome.

CONCLUSION

This study describes the natural history of classic galactosemia based on the hitherto largest data set.

Inducible Knockdown of Endothelial Protein Tyrosine Phosphatase-1B Promotes Neointima Formation in Obese Mice by Enhancing Endothelial Senescence

AIMS

Protein tyrosine phosphatase-1B (PTP1B) is a negative regulator of receptor tyrosine kinase signaling. In this study, we determined the importance of PTP1B expressed in endothelial cells for the vascular response to arterial injury in obesity.

RESULTS

Morphometric analysis of vascular lesions generated by 10% ferric chloride (FeCl₃) revealed that tamoxifen-inducible endothelial PTP1B deletion (Tie2.ER^T2-Cre × PTP1B^fl/fl; End.PTP1B knockout, KO) significantly increased neointima formation, and reduced numbers of (endothelial lectin-positive) luminal cells in End.PTP1B-KO mice suggested impaired lesion re-endothelialization. Significantly higher numbers of proliferating cell nuclear antigen (PCNA)-positive proliferating cells as well as smooth muscle actin (SMA)-positive or vascular cell adhesion molecule-1 (VCAM1)-positive activated smooth muscle cells or vimentin-positive myofibroblasts were detected in neointimal lesions of End.PTP1B-KO mice, whereas F4/80-positive macrophage numbers did not differ. Activated receptor tyrosine kinase and transforming growth factor-beta (TGFβ) signaling and oxidative stress markers were also significantly more abundant in End.PTP1B-KO mouse lesions. Genetic knockdown or pharmacological inhibition of PTP1B in endothelial cells resulted in increased expression of caveolin-1 and oxidative stress, and distinct morphological changes, elevated numbers of senescence-associated β-galactosidase-positive cells, and increased expression of tumor suppressor protein 53 (p53) or the cell cycle inhibitor cyclin-dependent kinase inhibitor-2A (p16INK4A) suggested senescence, all of which could be attenuated by small interfering RNA (siRNA)-mediated downregulation of caveolin-1. In vitro, senescence could be prevented and impaired re-endothelialization restored by preincubation with the antioxidant Trolox.

INNOVATION

Our results reveal a previously unknown role of PTP1B in endothelial cells and provide mechanistic insights how PTP1B deletion or inhibition may promote endothelial senescence.

CONCLUSION

Absence of PTP1B in endothelial cells impairs re-endothelialization, and the failure to induce smooth muscle cell quiescence or to protect from circulating growth factors may result in neointimal hyperplasia.

A Hydrothermal-Sedimentary Context for the Origin of Life

Critical to the origin of life are the ingredients of life, of course, but also the physical and chemical conditions in which prebiotic chemical reactions can take place. These factors place constraints on the types of Hadean environment in which life could have emerged. Many locations, ranging from hydrothermal vents and pumice rafts, through volcanic-hosted splash pools to continental springs and rivers, have been proposed for the emergence of life on Earth, each with respective advantages and certain disadvantages. However, there is another, hitherto unrecognized environment that, on the Hadean Earth (4.5-4.0 Ga), would have been more important than any other in terms of spatial and temporal scale: the sedimentary layer between oceanic crust and seawater. Using as an example sediments from the 3.5-3.33 Ga Barberton Greenstone Belt, South Africa, analogous at least on a local scale to those of the Hadean eon, we document constant permeation of the porous, carbonaceous, and reactive sedimentary layer by hydrothermal fluids emanating from the crust. This partially UV-protected, subaqueous sedimentary environment, characterized by physical and chemical gradients, represented a widespread system of miniature chemical reactors in which the production and complexification of prebiotic molecules could have led to the origin of life. Key Words: Origin of life-Hadean environment-Mineral surface reactions-Hydrothermal fluids-Archean volcanic sediments. Astrobiology 18, 259-293.