Restoration of flow in the aorta: a novel therapeutic target in aortic valve intervention

Aortic blood flow patterns are closely linked to the morphology and function of the left ventricle, aortic valve and aorta. These flow patterns demonstrate the exceptional adaptability of the cardiovascular system to maintain blood circulation under a broad range of haemodynamic workloads and can be altered in various pathophysiological states. For instance, normal ascending aortic systolic flow is predominantly laminar, whereas abnormal aortic systolic flow is associated with increased eccentricity, vorticity and flow reversal. These flow abnormalities result in reduced aortic conduit function and increased energy loss in the cardiovascular system. Emerging evidence details the association of these flow patterns with loss of aortic compliance, which leads to adverse left ventricular remodelling, poor tissue perfusion, and an increased risk of morbidity and death. In this Perspective article, we review the evidence for the link between aortic flow-related abnormalities and cardiovascular disease and how these changes in aortic flow patterns are emerging as a therapeutic target for aortic valve intervention in first-in-human studies.

Validation of 2D flow MRI for helical and vortical flows

PURPOSE

The main objective of this study was to develop two-dimensional (2D) phase contrast (PC) methods to quantify the helicity and vorticity of blood flow in the aortic root.

METHODS

This proof-of-concept study used four-dimensional (4D) flow cardiovascular MR (4D flow CMR) data of five healthy controls, five patients with heart failure with preserved ejection fraction and five patients with aortic stenosis (AS). A PC through-plane generated by 4D flow data was treated as a 2D PC plane and compared with the original 4D flow. Visual assessment of flow vectors was used to assess helicity and vorticity. We quantified flow displacement (FD), systolic flow reversal ratio (sFRR) and rotational angle (RA) using 2D PC.

RESULTS

For visual vortex flow presence near the inner curvature of the ascending aortic root on 4D flow CMR, sFRR demonstrated an area under the curve (AUC) of 0.955, p<0.001. A threshold of >8% for sFRR had a sensitivity of 82% and specificity of 100% for visual vortex presence. In addition, the average late systolic FD, a marker of flow eccentricity, also demonstrated an AUC of 0.909, p<0.001 for visual vortex flow. Manual systolic rotational flow angle change (ΔsRA) demonstrated excellent association with semiautomated ΔsRA (r=0.99, 95% CI 0.9907 to 0.999, p<0.001). In reproducibility testing, average systolic FD (FDsavg) showed a minimal bias at 1.28% with a high intraclass correlation coefficient (ICC=0.92). Similarly, sFRR had a minimal bias of 1.14% with an ICC of 0.96. ΔsRA demonstrated an acceptable bias of 5.72°-and an ICC of 0.99.

CONCLUSION

2D PC flow imaging can possibly quantify blood flow helicity (ΔRA) and vorticity (FRR). These imaging biomarkers of flow helicity and vorticity demonstrate high reproducibility for clinical adoption.

TRIALS REGISTRATION NUMBER

NCT05114785.

Multi-modality imaging in aortic stenosis: an EACVI clinical consensus document

In this EACVI clinical scientific update, we will explore the current use of multi-modality imaging in the diagnosis, risk stratification, and follow-up of patients with aortic stenosis, with a particular focus on recent developments and future directions. Echocardiography is and will likely remain the key method of diagnosis and surveillance of aortic stenosis providing detailed assessments of valve haemodynamics and the cardiac remodelling response. Computed tomography (CT) is already widely used in the planning of transcutaneous aortic valve implantation. We anticipate its increased use as an anatomical adjudicator to clarify disease severity in patients with discordant echocardiographic measurements. CT calcium scoring is currently used for this purpose; however, contrast CT techniques are emerging that allow identification of both calcific and fibrotic valve thickening. Additionally, improved assessments of myocardial decompensation with echocardiography, cardiac magnetic resonance, and CT will become more commonplace in our routine assessment of aortic stenosis. Underpinning all of this will be widespread application of artificial intelligence. In combination, we believe this new era of multi-modality imaging in aortic stenosis will improve the diagnosis, follow-up, and timing of intervention in aortic stenosis as well as potentially accelerate the development of the novel pharmacological treatments required for this disease.

Diagnosis, Classification, and Management Strategies for Mitral Annular Calcification: A Heart Valve Collaboratory Position Statement

Mitral annular calcium (MAC) with severe mitral valvular dysfunction presents a complex problem, as valve replacement, either surgical or transcatheter, is challenging because of anatomy, technical considerations, concomitant comorbidities, and advanced age. The authors review the clinical and anatomical features of MAC that are favorable (green light), challenging (yellow light), or prohibitive (red light) for surgical or transcatheter mitral valve interventions. Under the auspices of the Heart Valve Collaboratory, an expert working group of cardiac surgeons, interventional cardiologists, and interventional imaging cardiologists was formed to develop recommendations regarding treatment options for patients with MAC as well as a proposed grading and staging system using both anatomical and clinical features.

The difficult symbolic construction of physicians’ and nurses’ experiences working in COVID-19 intensive care units: A qualitative study on reports at a university public hospital in Southeastern Brazil

Introduction

Humanistic studies that explore symbolic aspects of the experience of working on the COVID-19 frontline are necessary. Do these professionals have psychic time to symbolize such acute experiences? We expect these preliminary findings of this research provide subsidies for discussing psychological management in groups with these professionals.

Objectives

To interpret emotional meanings reported by physicians and nurses on their experiences of working at COVID-19 intensive care units.

Methods

Clinical-qualitative design. Data collection with semi-directed interviews with open-ended questions in-depth applied to a sample of six professionals, closed by theoretical information saturation, in a Brazilian university general hospital. Trigger question: “Talk about psychological meanings of your experience in face of management of patients with COVID-19 at ICU”. Data treatment by the Seven Steps of the Clinical-Qualitative Content Analysis. Theoretical framework of Medical Psychology using Balintian concepts.

Results

We raised 3 categories. (1) Psychic time and absence of symbolization in face of the pandemic; (2) Denial as a defense or psychosocial adaptation mechanisms; (3) Tensions and family support: triggers of ambivalent emotional experiences.

Conclusions

Raw experience of COVID-19 pandemic did not allow for realization of symbolization. Psychological defenses are manifested, either to maintain balance or to deny the existence of dangers related to mental health. Presence of families and health team confirm that the feeling of loneliness is avoided. Anxieties related to the fear of contamination are recurrent. There is dual relationship regarding the emotional experiences of health professionals, but the data point to importance of looking at how these individuals perceive and experience the pandemic.

Disclosure

No significant relationships.

“It’s not only the bad side” - Experiences reported by health professionals working with women victims of sexual violence in a Brazilian university specialized outpatient service: A qualitative study

Introduction

Health Psychology is a scientific branch that studies interpersonal relationships in the field of emotions and behavior in clinical settings. Violence against women is a gender-based action that alarmingly affects the population, with sexual violence (SV) being one of its main phenomena. The complexity of the care offered to SV patients by clinical professionals impacts themselves, affecting their personal lives and the quality of their work.

Objectives

To explore symbolic emotional meanings attributed by health professionals to care and follow-up of women victims of SV in state service of reference of the Unified Health System.

Methods

Clinical-Qualitative design was used to guide semi-directed interviews with open-ended questions in-depth. Clinical-Qualitative Content Analysis was employed to treat data. Five participants make up the multi-professional team at the Hospital of the Woman of the State University of Campinas. Theoretical framework chosen to interpret categories was Balintian Medical Psychology.

Results

Three categories were selected for this presentation: The human anguishes as the main challenge and handling of working with sexual violence; “To see things progressing”: to the patient and together with the team, a facilitator of the work; and “I try to leave it on the three’s leaves”: the difficult attempt to separate work from personal life.

Conclusions

Taking care of SV is a very emotionally demanding task. Working with the team and see expected outcomes help clinical professionals deal with negative feelings, avoiding, for example, compensatory traumas. New research about social-cultural impacts of working with SV is important to develop institutional approaches of coping for health teams.

Disclosure

No significant relationships.

Perceptions reported by residents in psychiatry on oral health problems in their patients with severe mental disorders: a qualitative study at a Brazilian university specialized psychiatric service

Introduction

There is a greater prevalence of oral problems in patients suffering from severe mental illness than in the general population. The psychiatrist use to be, naturally, a health professional with great clinical influence over these patients. Do young psychiatrists in training include oral evaluations on their patients? How does this doctor perceive oral health care in the context of follow-up of people with chronic mental disorders?

Objectives

To interpret the meanings of the practice or not, regarding oral health guidelines, as reported by residents in psychiatry working in care and follow-up services to patients with severe disorders at a public university.

Methods

Clinical-qualitative design. Semi-directed interviews with open-ended questions in-depth carried out with six participants. Sample closed by saturation information criterion. Residents see their patients at the General Hospital of the State University of Campinas. Interview material, audio-recorded and transcribed in full, was treated by Clinical-Qualitative Content Analysis, using concepts of theoretical framework from Medical Psychology. Interviewer was a female professor of dentistry.

Results

From the discussion, two categories of analysis were selected for this presentation. (1) medical practice obeys the natural logic of construction of paradigmatic areas: historically, dentistry has created a care model with independence from medicine; (2) dentist is not called to participate in “collusion of anonymity”. This is an expression construct by the psychoanalyst Balint to describe the taking of relevant clinical decisions, without no professional assume the responsibility for these.

Conclusions

These meanings may guide changes in professional conduct as well as in the curriculum of medical training programs.

Disclosure

No significant relationships.

Adoptability and accuracy of point-of-care ultrasound in screening for valvular heart disease in the primary care setting

PURPOSE

Despite continued efforts, a majority of patients with valvular heart disease (VHD) remain undiagnosed and untreated. This study aimed to assess the adoptability and accuracy of point-of-care handheld echocardiographic assessments (POCE) in the primary care setting.

METHODS

Eleven previously untrained primary care providers were trained to use the Vscan Extend (GE, WI) POCE to assess VHD, left ventricular function (LVEF), and major extra-cardiac findings. Their assessments were compared to those of three blinded expert readers. A total of 175 patients underwent POCE assessments which were evaluated using Kappa statistics (κ) together with their estimated standard error, p value, and 95% CI bounds.

RESULTS

Each patient had a mean of 3.3 ± 1.1 (±SD) assessments performed. Identical or nearly identical agreement between previously untrained primary providers and expert readers was evident for the diagnosis of tricuspid regurgitation, mitral regurgitation, pericardial effusion, and volume status. These agreements were strongest in apical long axis (κ = 1, p < 0.001) and parasternal long and short axis views (κ > =0.82 p < 0.001), though agreement remained robust in apical 4-chamber views (κ ≥ 0.76). The agreements in LVEF assessment were identical in the apical long axis view (κ = 1, p < 0.001) and robust in the remaining 3 views (κ > =0.66, p < 0.001). The assessments of aortic stenosis (parasternal/long, κ = 0.42, and parasternal/short, κ = 0.47, both p < 0.001) were weak in their agreement.

CONCLUSION

Compared to expert echocardiography readers, the untrained providers' use of POCE for VHD shows high user adoptability and diagnostic accuracies in the primary care setting.

The left ventricular remodeling assessment by cardiac magnetic resonance in chronic aortic regurgitation; implications for outcome

Background

Chronic aortic regurgitation (AR) causes left ventricular (LV) volume overload resulting in progressive LV remodeling, which negatively affect clinical outcome. Clinical Guidelines recommend assessment of LV remodeling by echocardiography, but little is known about comparative remodeling quantification by cardiac magnetic resonance (CMR) and association with outcomes.

Purpose

To assess LV remodeling in AR by CMR, compared with echocardiographic measures and determine its impact on clinical outcome.

Methods

Patients with native, ≥moderate, chronic AR by echocardiography who underwent CMR exam within 90 days of diagnosis from January 2012 to February 2020 were enrolled. The endpoint was a composite of death, heart failure hospitalization, and heart failure symptom exacerbation during follow-up.

Results

The 178 patients included had median age (IQR) of 58 years (44–69), and most (88%, n=158) presented with no or minimal symptoms (NYHA class I/II). At diagnosis symptomatic vs. no/minimal symptoms patients presented with much more advanced LV remodeling by CMR (EDVI 133 [83–151] vs. 96 [80–123] p=0.024, ESVI 66 [46–85] vs. 42 [30–58], P=0.001) while echocardiography showed limited differences (EDVI 76 [57–93] vs. 65 [54–87] p=0.507, ESVI 38 [30–58] vs. 27 [20–42], p=0.072). During follow-up (3.3 years [1.6–5.8]), aortic valve replacement (AVR) was performed in 49 patients. In patients with no/minimal symptoms, the composite endpoint occurred in 54 (34%) patients including eight deaths and 30 heart failure hospitalizations. Patients with LV end-systolic volume index (LVESVi) &gt;45 ml/m2 by CMR had higher likelihood for composite endpoint (Panel A) confirmed in multivariate models, adjusting for age, sex, AVR (time-dependent), EuroSCORE2, and LV End-systolic-dimension-index (LVESDi) &gt;25 mm/2, with adjusted hazard ratio 1.84 [1.02–3.33], p&lt;0.044 (Panel B). LVESVi by CMR was at least as powerful in determining clinical outcomes as guideline-recommended Doppler-Echocardiographic variables.

Conclusion

Assessment of LV remodeling by CMR in patients with clinically significant AR is feasible in routine clinical practice, detects with high sensitivity LV remodeling associated with development of HF symptoms and is independently predictive of clinical outcome. Hence, CMR provides a powerful tool for evaluation and risk stratification of patients with AR.

Funding Acknowledgement

Type of funding sources: None. Panel APanel B

Computed tomography derived left ventricular global longitudinal strain associate with clinical outcomes in patients undergoing transcatheter aortic valve replacement

Funding Acknowledgements

Type of funding sources: None.

Background

Computed tomography angiography (CTA) is key imaging modality for procedure planning for transcatheter aortic valve replacement (TAVR). Functional assessment by CTA with LV global longitudinal strain (LVGLS) has recently shown to be feasible. However, there is limited data on its prognostic value in patients with severe aortic stenosis (AS) who treated with TAVR.

Purpose

To evaluate the association of baseline CTA-LVGLS with post-TAVR outcome.

Methods

 Patients who underwent contrast multiphasic gated CTA for TAVR planning were studied. LVGLS was measured using dedicated feature-tracking software (Medis®). Cox regression analysis evaluated the association of baseline LVGLS with a composite outcome of all-cause death and heart failure hospitalization after TAVR.

Results

A total of 431 patients were included (median [IQR] age, 83 [77,87]years; 44% female); the society of Thoracic Surgeons Predicted Risk of Mortality (STS-PROM) score, 3.3 [2.3,5.1]%; CTA-LVGLS, -18.0 [-21.6,-14.2]%; LV ejection fraction was preserved at 60 [55,65]%. After a median follow-up of 19 [13,27] months, 99 composite outcomes occurred after TAVR. On multivariable Cox regression analysis, LVGLS was associated with the risk of composite outcome even after adjustment for baseline characteristics (Figure A). Patients with reduced LVGLS (above the median &gt;-18.0%) had higher risk of the composite outcome than those with preserved GLS (p = 0.003; Figure B).

Conclusion

Baseline CTA-LVGLS was associated with the risk of death or heart failure hospitalization over the clinical and echocardiographic characteristics in severe AS patients undergoing TAVR.

Abstract Figure.

Computed tomography characteristics of patients with functional MR receiving MitraClip

Funding Acknowledgements

Type of funding sources: None.

Background

Percutaneous leaflet repair with the MitraClip device (Abbott Vascular, Menlo Park, CA) is safe and effective in patients with severe functional mitral regurgitation (FMR). Residual or recurrent MR may occur in up to 40% of patients and is associated with persistent symptoms and impaired survival. The anatomical characteristics associated with residual or recurrent MR after MitraClip are not well defined by computed tomography angiography (CTA) in FMR population.

Methods

A retrospective analysis of patients with significant FMR, who underwent retrospective-gated CTA at Minneapolis Heart Institute between July 2015 to January 2020, identified those who underwent percutaneous leaflet repair with MitraClip. Anatomical and functional parameters were assessed by pre-procedure CTA and compared between those with and without residual (≥2) MR.

Results

  A total of 25 patients were included (median[Q1, Q3]; age, 80[75, 85]; 44% men) and classified into ventricular FMR (V-FMR, n = 12) and atrial FMR (A-FMR, n = 13) according to anatomical and functional characteristics by CTA. 50% of V-FMR and 38% of A-FMR had residual/worsening MR. Among V-FMR patients with residual/worsening MR, shorter coaptation length was observed (2.2[2, 2.3] mm vs. 3.5[3, 4], p = 0.006) (Figure). No differences in anatomical or functional characteristics were seen in A-FMR patients.

Conclusion

Longer coaptation length in V-FMR is predictive of successful MitraClip procedure, whereas mitral annulus size and cardiac volumes are not.

&lt;Ventricular FMR&gt; Total (N = 12) No residual/no worsening MR (N = 6) Residual/worsening MR (N = 6) P value Septal-lateral diameter, mm 31.9 (30.5, 37.9) 32.2 (30.1, 39.8) 31.9 (29.5, 35) 0.749 Annulus area, cm&sup2; 11.2 (10.4, 13.6) 11.3 (10.1, 14.6) 11.1 (9.6, 12.6) 0.631 Tenting area, cm&sup2; 1.6 (1.3, 2.1) 1.6 (1.2, 2.2) 1.7 (1.2, 2.3) 0.873 Tenting height, mm 8.5 (6.5, 9.7) 8.5 (6.6, 9.3) 8.3 (6.3, 10.1) 0.749 Coaptation length, mm 2.6 (2.1, 3.5) 3.5 (3.0, 4.0) 2.2 (2.0, 2.3) 0.006 &lt;Atrial FMR&gt; Total (N = 13) No residual/no worsening MR (N = 8) Residual/worsening MR (N = 5) P value Septal-lateral diameter, mm 32.3 (29.5, 39.0) 32.0 (29.2, 39.9) 34.3 (30.8, 39.02) 0.464 Annulus area, cm&sup2; 10.3 (9.2, 14.7) 10.2 (9.0, 14.6) 12.4 (9.4, 14.7) 0.661 Tenting area, cm&sup2; 1.2 (0.8, 1.8) 1.1 (0.7, 2.2) 1.3 (0.7, 1.8) 0.884 Tenting height, mm 5.5 (4.1, 6.9) 6.3 (4.1, 8.7) 4.6 (3.7, 5.8) 0.213 Coaptation length, mm 2.3 (1.5, 2.8) 2.5 (1.4, 3.5) 1.9 (1.5, 2.6) 0.464 Comparison of baseline CT parameters between no residual/ no worsening MR and residual/ worsening MR Abstract Figure.

Diagnosis and risk stratification in hypertrophic cardiomyopathy using machine learning wall thickness measurement: a comparison with human test-retest performance

BACKGROUND

Left ventricular maximum wall thickness (MWT) is central to diagnosis and risk stratification of hypertrophic cardiomyopathy, but human measurement is prone to variability. We developed an automated machine learning algorithm for MWT measurement and compared precision (reproducibility) with that of 11 international experts, using a dataset of patients with hypertrophic cardiomyopathy.

METHODS

60 adult patients with hypertrophic cardiomyopathy, including those carrying hypertrophic cardiomyopathy gene mutations, were recruited at three institutes in the UK from August, 2018, to September, 2019: Barts Heart Centre, University College London Hospital (The Heart Hospital), and Leeds Teaching Hospitals NHS Trust. Participants had two cardiovascular magnetic resonance scans (test and retest) on the same day, ensuring no biological variability, using four cardiac MRI scanner models represented across two manufacturers and two field strengths. End-diastolic short-axis MWT was measured in test and retest by 11 international experts (from nine centres in six countries) and an automated machine learning method, which was trained to segment endocardial and epicardial contours on an independent, multicentre, multidisease dataset of 1923 patients. Machine learning MWT measurement was done with a method based on solving Laplace's equation. To assess test-retest reproducibility, we estimated the absolute test-retest MWT difference (precision), the coefficient of variation (CoV) for duplicate measurements, and the number of patients reclassified between test and retest according to different thresholds (MWT >15 mm and >30 mm). We calculated the sample size required to detect a prespecified MWT change between pairs of scans for machine learning and each expert.

FINDINGS

1440 MWT measurements were analysed, corresponding to two scans from 60 participants by 12 observers (11 experts and machine learning). Experts differed in the MWT they measured, ranging from 14·9 mm (SD 4·2) to 19·0 mm (4·7; p<0·0001 for trend). Machine learning-measured mean MWT was 16·8 mm (4·1). Machine learning precision was superior, with a test-retest difference of 0·7 mm (0·6) compared with experts, who ranged from 1·1 mm (0·9) to 3·7 mm (2·0; p values for machine learning vs expert comparison ranging from <0·0001 to 0·0073) and a significantly lower CoV than for all experts (4·3% [95% CI 3·3-5·1] vs 5·7-12·1% across experts). On average, 38 (64%) patients were designated as having MWT greater than 15 mm by machine learning compared with 27 (45%) to 50 (83%) patients by experts; five (8%) patients were reclassified in test-retest by machine learning compared with four (7%) to 12 (20%) by experts. With a cutoff point of more than 30 mm for implantable cardioverter-defibrillator, three experts would have changed recommendations between tests a total of four times, but machine learning was consistent. Using machine learning, a clinical trial to detect a 2 mm MWT change would need 2·3 times (range 1·6-4·6) fewer patients.

INTERPRETATION

In this preliminary study, machine learning MWT measurement in hypertrophic cardiomyopathy is superior to human experts with potential implications for diagnosis, risk stratification, and clinical trials.

FUNDING

European Regional Development Fund and Barts Charity.

Left ventricular remodeling after transcatheter mitral valve replacement with Tendyne

Background

Data on changes in left atrial (LA) and left ventricular (LV) volumes after transcatheter mitral valve replacement (TMVR) are limited.

Purpose

This study sought to describe the anatomical and functional changes in left-sided cardiac chambers by computed tomography angiography (CTA) from baseline to 1-month after TMVR with Tendyne prosthesis.

Methods

We analyzed patients who underwent TMVR with Tendyne prosthesis (Abbott Structural, Menlo Park, CA) between 2015 and 2018. Changes in LV end-diastolic volume (LVEDV), ejection fraction (LVEF), mass (LV mass), LA volume and global longitudinal strain (GLS) were assessed at baseline and at 1-month after TMVR with CTA. Specific Tendyne implant characteristics were identified and correlated with remodeling changes.

Results

A total of 36 patients (mean age 73±8 years, 78% men, 86% secondary MR) were studied. There were significant decreases in LVEDV (268±68 vs. 240±66ml, p&lt;0.001), LVEF (38±10 vs. 32±11%, p&lt;0.001), LV mass (126±37 vs. 117±32g, p&lt;0.001), LA volume (181±74 vs. 174±70 ml, p=0.027) and GLS (−12.6±5.1 vs. −9.5±4.0%, p&lt;0.001) from baseline to 1-month follow-up. Favorable LVEDV reverse-remodeling occurred in the majority (30 of 36 patients, or 83%). Closer proximity of the Tendyne apical pad to the true apex was predictive of favorable remodeling (pad distance: 25.0±7.7 vs. 33.5±8.8mm, p=0.02 for those with and without favorable remodeling).

Conclusions

TMVR with Tendyne results in favorable left-sided chamber remodeling in the majority of patients treated, as detected on CTA at 1-month after implantation. CTA identifies the favorable post-TMVR changes, which could be related to specific characteristics of the device implantation.

Funding Acknowledgement

Type of funding source: None

Frequency and clinical impact of different definitions of moderate aortic stenosis

Background

Current echocardiographic guidelines recommend five parameters to define severity of aortic stenosis (AS): peak velocity (PV), mean gradient (MG), aortic valve area (AVA), index AVA (AVAi), and dimensionless index (DI). However, the clinical utility of these parameters for patients with moderate AS largely remain unknown.

Objective

To investigate the clinical profiles and outcomes of patients with moderate AS according to five different definitions for severity.

Methods

Using standard echocardiographic definitions, we identified patients with moderate AS who were evaluated in our health care system from 2011 to 2012. Patient demographics, morbidities, and adverse events were reviewed, including death, heart failure (HF) admission, and aortic valve replacement (AVR).

Results

We enrolled 1,042 patients (age, 75±12 yrs; 40% women). Very few patients (4%) met all five criteria for moderate AS, while 49% had only one or two criteria met. DI was the most common parameter for defining moderate AS, employed in 93% of patients. Patients with area-based indices (i.e., AVA, AVAi, DI) had lower stroke volume index, lower mean gradients, lower peak velocities, and more morbidities in comparison to those flow-based definitions of severity (i.e., PV, MG). During a median follow-up of 5.7 years, overall survival was poor with all-cause mortality of 62.8%. Notably, there was no difference in the rates of mortality (range, 56.4 to 63.3%) or HF hospitalization (range, 28.9 to 32.2%) for groups defined by the five parameters, though patients with flow-based definitions more likely had AVR in follow-up.

Conclusions

Most patients with moderate AS meet the definition for severity with one or few criteria. Regardless of the method of definition for severity, a high rate of mortality and morbidity can occur in patients with moderate AS. Further study to optimize the clinical outcomes of patients with moderate AS is warranted.

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): Minneapolis Heart Institute Foundation

P212 Computed tomography derived left ventricular outflow tract area downgrades severity of prosthesis-patient mismatch after transcatheter aortic valve replacement

Background

Prosthesis-patient mismatch (PPM) is associated with poor outcomes after surgical aortic valve replacement, but evidence in the era of transcatheter aortic valve replacement (TAVR) is small. Although PPM is conventionally defined by transthoracic echocardiogram (TTE) derived indexed effective orifice area (EOAi), TTE may underestimate left ventricular outflow tract (LVOT) area when compared with cardiac computed tomography angiography (CTA).

Purpose

To evaluate the inter-modality (TTE vs CTA) agreement and inter-valve (balloon-expanding valve (BEV) vs. self-expandable valve (SEV)) differences in EOAi and the severity of PPM after TAVR.

Methods

We analyzed all patients who underwent TAVR between 2015 to 2017and who had both of CTA and TTE at 30-days after TAVR. EOAi was calculated using the continuity equation and then indexed to body surface area as per guidelines using TTE derived LVOT diameter (EOAi-TTE) or post-procedure CTA derived LVOT area (EOAi-CTA). The external LVOT diameter was measured at inflow of TAVR bioprosthetic stent frame as per recommendations. The EOAi was used to define the grading severity of PPM: None (&gt; 0.85 cm²/m²); Moderate (0.65 to 0.85 cm²/m²); and Severe (&lt; 0.65 cm²/m²). Paired or Student t-test and Chi-square test were used to assess the inter-modality and inter-valve difference.

Results

A total of 280 patients were included (the mean age, 81.2 ± 8.1 years; 48%, female). BEV was used in 150 patients (54%). The mean EOAi-TTE vs. EOAi-CTA was 1.00 ± 0.32 and 1.41 ± 0.50 cm²/m², respectively, p &lt; 0.001. Prevalence of severe (TTE 9% versus CTA 4%, p &lt; 0.01) and moderate (TTE 28% versus CTA 7%, p &lt; 0.01) PPM was lower when adjudicated by CTA (Figure-Panel A). There was a trends towards smaller EOAi by either TTE (0.97 ± 0.31 vs. 1.04 ± 0.33, p = 0.07) or CTA (1.38 ± 0.45 vs. 1.46 ± 0.56, p = 0.21) for BEV vs. SEV (Figure-Panel B). There was no significant difference in the severity of PPM defined by either EOAi-TTE (Figure-Panel C) or EOAi-CTA (Figure-Panel D) between these patients.

Conclusion

EOAi-CTA was larger and downgraded the severity of PPM than the EOAi-TTE. There was no significant difference in the severity of PPM defined by post-procedure CT between patients treated with BEV and those with SEV.

Abstract P212 Figure.

6097Aminoterminal proB-type natriuretic peptide: a key parameter to optimise therapeutic management of low-flow, low-gradient aortic stenosis

Background

B-type natriuretic peptide (BNP) and aminoterminal-proBNP (NT-proBNP) are well established surrogates of LV function impairment. However, data are scarce regarding their prognostic value to risk-stratify patients with classical low-flow, low-gradient aortic stenosis (LFLG-AS, with low left ventricular [LV] ejection fraction).

Methods

The TOPAS study is a prospective observational cohort of 240 patients with aortic valve area <0.6 cm2/m2, mean gradient<40 mmHg and LVEF<50%. True severe AS was adjudicated using flow independent grading schemes.

Results

BNP significantly predicted one-year (area under the receiver operating-characteristic curve [AUC]) 0.62±0.04, p=0.026) but not three-year mortality. After adjustment for the severity of AS, initial treatment (aortic valve replacement [AVR] vs. conservative management [ConsRx]), age, sex and the EuroSCORE (Model#1), BNP-ratio>550 pg/ml had a trend to predict time to death (HR=2.14 [1.00–4.58], p=0.05). In contrast, NT-proBNP ratio significantly predicted both one and three-year mortality (AUC=0.67±0.04 and 0.66±0.05, both p=0.001), and independently predicted time to death (HR=1.39 per 1 unit of Log transformed NT-proBNP [1.11–1.74], p=0.004). In a head-to-head comparison (108 patients with both biomarkers), the AUCs to predict one and thre-year mortality were significantly higher with NT-proBNP versus BNP (p<0.009). NT-proBNP but not BNP independently predicted mortality and significantly improved Model#1 (Likelihood ratio test Chi2=15.95, p<0.001). The category-free net reclassification index of NT-proBNP was 0.71 (p=0.008) versus 0.38 (p=0.15) for BNP. Furthermore, there was a marked survival benefit associated with AVR in patients with NT-proBNP ≥1700 pg/ml (adjusted hazard ratio (aHR) associated to AVR vs conservative management=0.52 [0.31–0.85], p=0.009), while those<1700 pg/ml had excellent one-year survival under ConsRx (only one death [4.5±4.4%] at one year as compared to 23 [37±6.2%] for ConsRx-NTproBNP>1700, aHR=0.11 [0.01–0.83], p=0.033). The survival benefit associated with AVR interacted with NT-proBNP (p<0.001) but not with true or pseudosevere AS (p=0.53 for interaction), suggesting that NT-proBNP might identify moderate AS patients but sufficiently severe valvulo-ventricular disease to justify AVR.

Survival according to NT-proBNP and AVR

Conclusion

NT-proBNP appears to be an excellent biomarker for the clinical purpose of risk-stratifying classical LFLG-AS. A threshold of 1700 pg/ml i.e. close to the diagnostic threshold for heart failure in acute dyspnea, was a strong independent determinant of the survival benefit associated with aortic valve replacement. Our findings suggest that NT-proBNP should be preferred over BNP.

Acknowledgement/Funding

Canadian Institute of Health Research

6099Impact of aortic valve replacement on outcomes of patients with low-flow, low-gradient moderate aortic stenosis

Background

Aortic valve replacement (AVR) is recommended for patients with low-flow, low-gradient (LFLG) and true-severe aortic stenosis (TSAS). However, there is very few data on the potential benefit of AVR in patients with LFLG pseudo-severe (i.e. moderate) AS (PSAS).

Methods

Consecutive patients with aortic valve area ≤0.6 cm2/m2, mean gradient <40 mmHg were prospectively recruited in a multicenter observational cohort study. The patients were categorized in TSAS vs. PSAS using previously reported thresholds of flow-independent parameters of AS severity (projected valve area at normal flow rate ≤1.0 cm2 and/or aortic valve calcium score by CT >1200 AU in women and >2000 AU in men). To account for between-treatment-group differences, inverse probability-of-treatment weighting was combined to Cox proportional hazards regression.

Results

Among the 430 patients included in this study, 297 (69%) were classified as TSAS and 274 (57%) underwent AVR. Of note, 21% of the patients treated by AVR were classified as PSAS. In patients managed conservatively (ConsRx), 52% had PSAS and 48% TSAS. During a median follow-up of 28 months [8–60], 198 patients died. The adjusted weighted hazard ratio (awHR) of death associated with AVR as compared to ConsRx was 0.42 [0.24–0.73] (p<0.0001, Figure1-Panel-A). This survival benefit associated with AVR was observed not only in patients with TSAS but also in those with PSAS (awHR: 0.29 [0.12–0.70]; p=0.006, Figure1-Panel-B).

Figure 1

Conclusion

The results of this study suggest that AVR is associated with a survival benefit not only in LFLG patients with TSAS but also in those with PSAS. Randomized trials are needed to confirm the benefit of AVR in patients with moderate AS and depressed LV systolic function.

Acknowledgement/Funding

Canadian Institute of Health Research

1337Myocardial extracellular volume in patients with aortic stenosis undergoing valve intervention - A multicentre T1 mapping study

Background

The development of myocardial fibrosis is a key mechanism in the transition from compensated hypertrophy to heart failure in aortic stenosis (AS). Focal and diffuse fibrosis can be quantified using cardiac magnetic resonance (CMR) imaging late gadolinium-enhanced (LGE) and T1 mapping techniques.

Purpose

To assess T1 mapping measures of fibrosis in patients with severe AS referred for aortic valve intervention, and determine their associations with clinical characteristics, disease severity and long-term clinical outcome.

Methods

In this international prospective cohort study, patients with severe AS underwent contrast enhanced CMR with T1 mapping and LGE prior to aortic valve intervention. Image analysis was performed by a single core laboratory and the extracellular volume fraction [ECV%] calculated from T1 mapping images. The presence of LGE was determined visually and quantified using the full-width-at-half-maximum technique.

Results

Four-hundred and forty patients (70±10 years, 59% male) from ten international centres were enrolled. Aortic valve intervention was performed 15 [4 to 58] days following CMR. Within a follow-up of 3.8 [2.8 to 4.6] years, 52 patients died.

ECV% (mean 27.7±3.6%) correlated with increasing age, Society of Thoracic Surgeons Predicted Risk of Mortality score, known coronary artery disease, lower peak aortic-jet velocity, larger left ventricular (LV) mass, lower LV ejection fraction, and presence of LGE (P<0.05 for all). Following adjustment for all demographic and clinical variables, ECV% remained associated with age (P=0.028), LV ejection fraction (P<0.001) and presence of LGE (P=0.035).

Univariable predictors of all-cause mortality included age, male sex, impaired LV ejection fraction and presence of LGE (all P<0.05). A progressive increase in all-cause mortality was seen across tertiles of ECV% (17.3, 31.6 and 52.7 deaths per 1000 patient-years; log-rank test, P=0.009). ECV% was independently associated with all-cause mortality following adjustment for age, sex, impaired LV ejection fraction and presence of LGE (HR per unit increase in ECV: 1.10, 95%, (1.02–1.19), P=0.013).

ECV440 abstract iamge

Conclusion

In patients with severe aortic stenosis scheduled for aortic valve intervention, extracellular volume-based T1 mapping correlates with LV decompensation. ECV% is a strong independent predictor of late all-cause mortality and is a potential therapeutic target.

SHR5: a novel plant receptor kinase involved in plant-N2-fixing endophytic bacteria association

Endophytic nitrogen-fixing bacteria have been isolated from graminaceous plants such as maize, rice, and sugarcane. They are thought to promote plant growth, not only by fixing nitrogen, but also by the production of plant hormones. The molecular mechanisms involved in this interaction are not yet clear. In this work, the identification of a receptor-like kinase (RLK), named SHR5, which may participate in signal transduction involved in the establishment of plant-endophytic bacteria interaction is described for the first time. SHR5 seems to be part of a novel subclass of RLKs present in a wide range of plant species. The expression of this gene is down-regulated in sugarcane plants associated exclusively with beneficial endophytic bacteria and is not a general response caused by micro-organisms or abiotic stress. In addition, more successful sugarcane-endophytic bacteria associations have a more pronounced decrease in SHR5 expression, suggesting that SHR5 mRNA levels in plant cells are inversely related to the efficiency of the association.

Intravascular source of adenosine during forearm ischemia in humans: implications for reactive hyperemia

It is believed that adenosine is released in ischemic tissues and contributes to reactive hyperemia. We tested this hypothesis in the human forearm using microdialysis to estimate interstitial and intravascular levels of adenosine and caffeine withdrawal to potentiate endogenous adenosine and determine its effect on reactive hyperemia. Forearm blood flow response to ischemia was measured by air plethysmography before and 60 hours after the last dose of caffeine (250 mg TID for 7 days, n=6). Forearm blood flow increased by 274+/-66% and 467+/-97% after 3 minutes of forearm ischemia, before and during caffeine withdrawal, respectively (P<0.05). Thus, caffeine withdrawal enhances reactive hyperemia. To determine the source of adenosine, we measured interstitial adenosine with the use of a microdialysis probe inserted into the flexor digitorum superficialis muscle of the forearm, and we measured intravascular adenosine with the use of a microdialysis probe inserted retrogradely into the medial cubital vein. Dialysate samples were collected at 15-minute intervals during resting, forearm ischemia, and recovery periods. Forearm ischemia failed to increase muscle dialysate concentrations of adenosine but did increase intravascular dialysate adenosine 2.1-fold, from 0.61+/-0.12 to 1.28+/-0.39 micromol/L (P<0.01, n=8). Intravascular dialysate concentrations of thromboxane B2 did not increase during ischemia, ruling out platelet aggregation as a source of adenosine. These results support the hypothesis that endogenous adenosine contributes to reactive hyperemia and indicate that the major source of adenosine in the human forearm is intravascular. We speculate that endothelial cells are the source of intravascular adenosine during ischemia.