Improved diagnostic accuracy for apical hypertrophic cardiomyopathy

Introduction

The diagnosis of apical hypertrophic cardiomyopathy (ApHCM) is contingent on demonstrating apical maximum wall thickness (MWT) of ≥15mm; the same threshold as other HCM subtypes. However, the myocardium naturally tapers towards the apex in healthy individuals, so ≥15mm MWT is proportionately higher in the apex than in naturally thicker basal segments. Using cardiac magnetic resonance (CMR), relative ApHCM has been described (typical ECG features, loss of apical tapering, cavity obliteration but hypertrophy <15mm). Wall thickness measurement using machine learning now exceeds human performance.

Purpose

We aimed to redefine the optimal diagnostic threshold for ApHCM using segment-specific criteria based on a large cohort of healthy control subjects.

Methods

Segmental wall thickness was measured using healthy subjects from the UK Biobank using a clinically validated machine learning algorithm1,2. A normative reference range was established for all 16 segments, conditioned to body surface area (BSA), sex and age. Derived segment-specific wall thickness thresholds were used to define optimal disease thresholds for patients clinically managed with overt (MWT ≥15mm) and relative ApHCM (MWT <15mm, but typical ECG and imaging findings).

Results

4118 UK biobank subjects were used to define normal segmental thicknesses and reference ranges. These were applied to ApHCM (73 overt, 31 relative). There were no apical wall thickness age related differences. The upper limit of the 95% confidence interval corresponded to a combined maximum apical MWT for both males and females of 10.4mm using non-indexed measurement, or 5.6mm/m2 when indexed to BSA. Non-indexed segmental threshold identified 100% of ApHCM patients (true positives), 81% (25 of 31) relative ApHCM and 3% (115 of 4118) of healthy UK biobank subjects (false positives). Indexed segmental thresholds improved the diagnostic potential in relative ApHCM without an increase in false positives (100% of ApHCM patients, 84% (26 of 31) of relative ApHCM patients, and 3% healthy UK biobank (127 of 4118).

Conclusion

We propose new diagnostic criteria for ApHCM using segmental indexed apical wall thickness of >5.6 mm/m2 to better identify inappropriate apical hypertrophy in those whose wall thickness does not meet current criteria for diagnosis.

Funding Acknowledgement

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

Advanced microstructural substrate detection in pre-hypertrophic HCM and its relationship to arrhythmogenesis; a hybrid CMR-ECG-Imaging study

Background

Hypertrophic cardiomyopathy is defined in three domains; clinically by unexplained hypertrophy, genetically by sarcomeric gene mutations and histologically by disarray, small vessel disease and fibrosis. Both ischaemia and myocyte disarray have been implicated in arrhythmogenesis and sudden cardiac death but whether disarray occurs before hypertrophy and its relationship to ischaemia is unknown.

Diffusion-tensor CMR, perfusion mapping & ECG Imaging (ECGI) can measure disarray, ischaemia and electrical aberrance respectively in vivo. We aimed to investigate these in genotype positive (G+) subjects without hypertrophy (LVH−) to identify further subclinical manifestations of gene expression and whether these relate to ventricular arrhythmia formation.

Methods

Diffusion-tensor CMR (3-Tesla) using a motion-compensated spin-echo sequence was acquired in 3 short-axis slices. Quantitative adenosine stress perfusion mapping was performed using standard clinical protocols. A novel ECGI vest, containing 256 unipolar electrodes acquired a 5-minute recording of body-surface potentials to quantify conduction and repolarisation dynamics intervals.

Results

ECGI/CMR was performed on 68 mutation carriers from 64 families and 24 age sex and ethnicity matched healthy controls. Of the mutation carriers, median age was 33 (24–41 years), 57% (39) were female, and 79% (54) were white. Mutations were 39 (57%) MYBPC3, 19 (28%) MYH7, 1 (1%) MYL2 and 9 (12%) were thin filament/non-sarcomeric mutations. There was no significant difference in ejection fraction or LV mass, however G+LVH− had a higher maximum wall thickness (9 (9–10) vs 8 (7–9) mm p=0.003).

Compared to healthy volunteers, G+LVH− individuals had more perfusion defects (18/64 (30%) vs 0, p=0.004), lower Fractional Anisotropy (FA) (suggestive of more disarray) (0.32±0.02 vs 0.34±0.02, p<0.0001) and more prolonged Activation–Recovery Intervals (ARI, a surrogate for action potential duration (259±40 vs 240±31 ms, p=0.03).

In G+LVH−, patients with perfusion defects had more prolonged ARI (263 (248 vs 292) vs 246 (225–283) ms, p=0.03) and lower FA suggestive of more disarray (0.32±0.2 vs 0.31±0.1, p=0.04).

Conclusion

Ischaemia, myocyte disarray and electrical abnormalities occur even in the absence of hypertrophy in HCM. These abnormalities associate to form a complex a clinical phenotype.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): British Heart FoundationBarts Charity

Heterozygous APOE ε4 carriage associates with improved myocardial efficiency in older age

Background

Carriage of the ancestral APOE ε4 allele confers a risk of developing Alzheimer's and coronary artery disease, but its persistence in human populations also suggests some potential survival advantages. To date it remains unclear whether APOE ε4 carriage independently associates with a better or worse long-term cardiac phenotype.

Purpose

Using data from the 1946 National Survey of Health and Development (NSHD) birth cohort, we investigated whether APOE ε4 carriage associates with adverse or beneficial left ventricular (LV) size and function parameters by echocardiography in older age.

Methods

Based on the presence or absence of APOE ε4, genotypes were divided into: non-APOE ε4 (ε2ε2, ε2ε3, ε3ε3), heterozygous-APOE ε4 (ε2ε4 and ε3ε4) and homozygous-APOE ε4 (ε4ε4). Echocardiographic data at 60–64 years included: left ventricular ejection fraction (LV EF), E/e', systolic and diastolic LV posterior wall and interventricular septal thickness (LVPWTs/d, IVSs/d), and body-surface area indexed LV mass (LVmassi) and myocardial contraction fraction (MCFi). Generalized linear models explored associations between APOE ε4 genotypes as exposures and echocardiographic biomarkers as outcomes. As a combination of gene variants, APOE ε genotype is expected to be an instrumental variable and therefore unconfounded. Thus, Model 1 was unadjusted. To obtain more precise regression estimates, Model 2 was adjusted for factors associated with the outcome, namely sex and socio-economic position (SEP). To explore the mechanistic pathway downstream of APOE ε genotype but upstream of the echocardiographic outcomes, subsequent models were adjusted for mediators as follows: Model 3 for body mass index, Model 4 for the presence of cardiovascular disease (CVD), Model 5 for diabetes, Model 6 for high cholesterol and Model 7 for hypertension.

Results

1464 participants were included. Compared to non-APOE ε4 and homozygous groups, heterozygous-APOE ε4 individuals had similar cardiac phenotypes in terms of EF, E/e', LVPWTs/d, IVSs/d and LVmassi but had a 7% higher MCFi 95% confidence interval [CI]: 1%-13%, p=0.017) which persisted even after adjustment for sex and SEP (95% CI 1%-12%, p=0.026) that was attenuated to 6% after adjustment for CVD (95% CI 0–13% p=0.050) and hypertension (95% CI 1–13% p=0.022).

Conclusion

The heterozygous-APOE ε4 state associates with improved myocardial shortening in older age resulting in greater LV stroke volume generation per 1 mL of myocardium. As we found no association between APOE ε4 carriage and LVPWTs/d, IVSs/d or LVmassi, MCFi enhancement may be mediated by improved myocardial energetics and contractility, with calcium and androgens potentially implicated, rather than through pathological ventricular thickening. Although a dose relationship is normally expected with ε4 carriage, any benefit from increased energetics and contractility is likely to be counterbalances by the higher risk of CVD and cardiovascular risk factors.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): UK Medical Research Council British Heart Foundation

Clinical presentation, disease course, and outcome of COVID-19 in hospitalized patients with and without pre-existing cardiac disease: a cohort study across 18 countries

AIMS

Patients with cardiac disease are considered high risk for poor outcomes following hospitalization with COVID-19. The primary aim of this study was to evaluate heterogeneity in associations between various heart disease subtypes and in-hospital mortality.

METHODS AND RESULTS

We used data from the CAPACITY-COVID registry and LEOSS study. Multivariable Poisson regression models were fitted to assess the association between different types of pre-existing heart disease and in-hospital mortality. A total of 16 511 patients with COVID-19 were included (21.1% aged 66-75 years; 40.2% female) and 31.5% had a history of heart disease. Patients with heart disease were older, predominantly male, and often had other comorbid conditions when compared with those without. Mortality was higher in patients with cardiac disease (29.7%; n = 1545 vs. 15.9%; n = 1797). However, following multivariable adjustment, this difference was not significant [adjusted risk ratio (aRR) 1.08, 95% confidence interval (CI) 1.02-1.15; P = 0.12 (corrected for multiple testing)]. Associations with in-hospital mortality by heart disease subtypes differed considerably, with the strongest association for heart failure (aRR 1.19, 95% CI 1.10-1.30; P < 0.018) particularly for severe (New York Heart Association class III/IV) heart failure (aRR 1.41, 95% CI 1.20-1.64; P < 0.018). None of the other heart disease subtypes, including ischaemic heart disease, remained significant after multivariable adjustment. Serious cardiac complications were diagnosed in <1% of patients.

CONCLUSION

Considerable heterogeneity exists in the strength of association between heart disease subtypes and in-hospital mortality. Of all patients with heart disease, those with heart failure are at greatest risk of death when hospitalized with COVID-19. Serious cardiac complications are rare during hospitalization.

Childhood bradycardia associates with atrioventricular conduction defects in older age: a longitudinal birth cohort study

Background

A high resting heart rate (RHR) has been associated with cardiovascular morbidity and mortality. However, little is known about the long-term effects of childhood bradycardia.

Purpose

This study aimed to explore the association between childhood bradycardia and later-life cardiac phenotype using longitudinal data from the 1946 Medical Research Council National Survey of Health and Development (NSHD) birth cohort.

Methods

RHR was recorded at ages 6 and 7 to provide the bradycardia exposure defined as a childhood RHR&lt;75. Three outcomes were studied: i) echocardiographic data at 60–64 consisting of ejection fraction (EF), left ventricular mass index (LVmassi), myocardial contraction fraction index (MCFi) and E/e'; ii) electrocardiographic (ECG) evidence of atrio-ventricular (AV) conduction defects (Minnesota categories: 6-1, 6-2-1, 6-2-2, 6-2-3, 6-3, 6-8, 8-5-1, 8-5-2, 8-6-1, 8-6-2, 8-6-3 and 8-6-4) or ventricular conduction defects (any Minnesota group 7) by age 60–64; and iii) all-cause and cardiovascular mortality. Generalized linear models (glm) with gamma distribution were used for echocardiographic analyses, glms with binomial distribution for ECG analyses and Cox proportional hazards models for mortality. Adjustment was made for relevant demographic and health-related covariates, and for multiple testing. In order to account for within-subject correlated repeated measures at 6 and 7 years of age, mixed glms (glmms) were used as a sensitivity analysis. To explore any nonlinear relationships, we modeled each outcome as a sum of best fitting fractional polynomials of RHR at 6 and 7 (as continuous variables) and covariates using a “closed test procedure” with backward elimination.

Results

The number of participants included was: 4381 for mortality, 1631 for ECG and 1617 for echocardiography analyses. Childhood bradycardia was associated with male sex (p&lt;0.0001) and higher BMI (p=0.009). In fully adjusted models, childhood bradycardia was associated with 2.91 higher odds of AV conduction defects (95% confidence interval [CI] 1.59–5.31, p=0.0005), even at a false discovery rate of 0.05. Associations persisted in random coefficients glmm models (odds ratio 2.50, 95% CI 1.01–4.31). The fractional polynomials analyses revealed that the log odds of AV conduction defects at 60–64 years of age were linearly associated with RHR at 7 years. There was no association between bradycardia in childhood and ventricular conduction defects, echocardiographic parameters or mortality outcomes.

Conclusions

Longitudinal data indicate that childhood bradycardia trebles the odds of having AV conduction defects, but does not influence mortality or heart size and function in older age. As one in three older adults with AV conduction defects will have been bradycardic in childhood, future research should concentrate on identifying children at risk, the potential mechanisms involved and whether AV blocking drugs accelerate nodal dysfunction.

Funding Acknowledgement

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): British Heart Foundation (MyoFit46 Special Programme Grant SP/20/2/34841)

Prospective case-control study of cardiovascular abnormalities six months following mild COVID-19 in healthcare workers

Funding Acknowledgements

Type of funding sources: Public Institution(s). Main funding source(s): Barts Charity UCLH Charity

OnBehalf

COVIDsortium

Background

Recent CMR studies have reported cardiac abnormalities after COVID-19 are common, even after mild, non-hospitalised illness with evidence of ongoing myocardial inflammation.  Such a prevalence of chronic myocarditis after mild disease has prompted societal concerns in diverse domains, and suggests that screening should be considered post COVID-19, even in asymptomatic individuals.  Cardiovascular magnetic resonance (CMR) has proven utility for diagnosis in patients with COVID-19 infection and elevated troponin from unclear causes by measuring cardiac structure, function, myocardial scar (late gadolinium enhancement) and oedema (T1 and T2 mapping).

Objectives

We aimed to determine the prevalence and extent of late cardiac and cardiovascular sequelae after mild non-hospitalised SARS-CoV-2 infection.

Methods

Participants were recruited from COVIDsortium, a three-hospital prospective study of 731 healthcare workers who underwent first wave weekly symptom, PCR and serology assessment over 4 months, with seroconversion in 21.5% (n = 157). At 6 months post infection, 74 seropositive and 75 age-, sex-, ethnicity-matched seronegative controls were recruited for cardiovascular phenotyping (comprehensive phantom-calibrated Cardiovascular Magnetic Resonance and blood biomarkers). Analysis was blinded, using objective AI analytics where available.

Results

149 subjects (mean age 37 years, range 18-63, 58% female) were recruited. Seropositive infections had been mild with case definition/non-case definition/asymptomatic disease in 45(61%), 18(24%) and 11(15%) with one person hospitalised (for 2 days). Between seropositive and seronegative groups, there were no differences in cardiac structure (left ventricular volumes, mass; atrial area), function (ejection fraction, global longitudinal shortening, aortic distensibility), tissue characterisation (T1, T2, ECV mapping, late gadolinium enhancement) or biomarkers (troponin, NT-proBNP).  With abnormal defined by the 75 seronegatives (2 standard deviations from mean, e.g. EF &lt; 54%, septal T1 &gt; 1072ms, septal T2 &gt; 52.4ms), individuals had abnormalities including reduced EF (n = 2, minimum 50%), T1 elevation (n = 6), T2 elevation (n = 9), LGE (n = 13, median 1%, max 5% of myocardium), biomarker elevation (borderline troponin elevation in 4; all NT-proBNP normal). These were distributed equally between seropositive and seronegative individuals.

Conclusions

Cardiovascular abnormalities are no more common in seropositive vs seronegative otherwise healthy, workforce representative individuals 6 months post mild SARS-CoV-2 infection.  Our study provides societal reassurance for the cardiovascular health of working-aged individuals with convalescence from mild SARS-CoV-2. Screening asymptomatic individuals following mild diseases is not indicated.

AS-amyloidosis. Dual pathology or novel disease? A multimodality, multi-centre assessment across health and disease

Funding Acknowledgements

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

onbehalf

AS-Amyloidosis consortium

Background

The coexistence of severe aortic stenosis (lone AS) and transthyretin cardiac amyloidosis (lone amyloidosis) is common, but the resultant AS-amyloidosis phenotype is unclear.

Purpose

We characterised AS-amyloidosis, hypothesizing that the dual insult of AS-amyloidosis results is a severe phenotype.

Methods

We compared four cohorts with deep phenotyping: 81 older age controls, 359 lone AS, 36 AS-amyloidosis (Perugini grade 2 and 3) and 107 lone amyloidosis (Perugini grade 2 and 3).

Results

AS-amyloidosis was similar to lone AS with respect to left ventricular mass and LVEF (57 (45, 64)%). It was similar to lone amyloidosis with respect to lateral S" (0.04 (0.03, 0.06) m/s), NT-proBNP (4149 (1449, 6459) ng/L) and troponin T (56 (34, 100) ng/L). Whilst, prevalence of carpal tunnel syndrome (CTS) (17%) and diastolic function (E/A ratio 1.1 (0.8, 2.8)) were intermediate.

Conclusion

AS-amyloidosis is not a double insult from AS and amyloidosis, but a mixed phenotype with features similar to lone amyloidosis (cardiac biomarkers), lone AS (remodelling and LVEF) or intermediate (diastology and CTS).

Characteristics across all 4 groups Variable Older age controls (n = 81) Lone AS (n = 359) AS-amyloidosis (n = 36) Lone amyloidosis (n = 107) P value Age (years) 82 (80, 84)*†‡ 85 (80, 88)§∞ 88 (85, 92)# 80 (75, 84) &lt;0.005 Sex (% male) 69 *‡ 49 ∞ 61 # 94 &lt;0.005 Carpal tunnel syndrome (%) 0 2 § 17 # 38 &lt;0.005 Voltage/mass ratio 0.22 (0.14, 0.27)‡ 0.18 (0.13, 0.28)∞ 0.18 (0.09, 0.21)# 0.07 (0.05, 0.10) &lt;0.005 NT-ProBNP (ng/L) 131 (66, 221)*†‡ 1629 (639, 3941)§∞ 4149 (1449, 6459) 2888 (1755, 5483) &lt;0.005 hsTnT (ng/L) 12 (8, 17)*†‡ 24 (15, 40)§∞ 56 (34, 100) 62 (41, 82) &lt;0.005 Inferolateral wall thickness (cm) 0.9 (0.8, 1.0)*†‡ 1.1 (0.9, 1.3)∞ 1.3 (1.1, 1.5)# 1.7 (1.6, 1.9) &lt;0.005 Anteroseptal wall thickness (cm) 1.0 (0.9, 1.2)*†‡ 1.4 (1.2, 1.6)§∞ 1.5 (1.3, 1.8) 1.7 (1.6, 1.9) &lt;0.005 Indexed LV mass (g/m2) 79 (66, 102)*†‡ 128 (99, 152)∞ 126 (116, 140)# 174 (159, 200) &lt;0.005 LVEF (%) 59 (54, 63)‡ 59 (50, 65)∞ 57 (45, 64)# 39 (31, 48) &lt;0.005 Lateral S" (m/s) 0.08 (0.07, 0.09)*†‡ 0.07 (0.05, 0.08)§∞ 0.05 (0.04, 0.07) 0.05 (0.04, 0.06) &lt;0.005 Septal S" (m/s) 0.06 (0.06, 0.08)*†‡ 0.05 (0.04, 0.06)∞ 0.04 (0.03, 0.06) 0.04 (0.03, 0.05) &lt;0.005 E/A 0.7 (0.6, 0.8)*†‡ 0.8 (0.7, 1.3)§∞ 1.1 (0.8, 2.8)# 2.4 (1.8, 3.3) &lt;0.005 RV Wall thickness (cm) 0.4 (0.3, 0.4)*†‡ 0.4 (0.4, 0.6)∞ 0.6 (0.4, 0.7)# 0.8 (0.7, 1.0) &lt;0.005 TAPSE (cm) 2.4 (2.0, 2.7)*†‡ 2.1 (1.6, 2.5)∞ 1.9 (1.5, 2.1)# 1.4 (1.2, 1.9) &lt;0.005 Classical LFLG AS (%) 9 13 0.472 * p &lt; 0.05, Old age control vs Lone AS † p &lt; 0.05, Old age control vs AS-amyloidosis ‡ p &lt; 0.05, Old age control vs Lone amyloidosis § p &lt; 0.05, Lone AS vs AS-amyloidosis ∞ p &lt; 0.05, Lone AS vs Lone amyloidosis # p &lt; 0.05, AS-amyloidosis vs Lone amyloidosis Abstract Figure. AS-amyloidosis compared to other cohorts

Interaction of stroke volume and myocardial phenotype in patients with severe aortic stenosis referred for intervention: outcome data from the BSCMR AS700 study

Funding Acknowledgements

Type of funding sources: None.

onbehalf

The BSCMR Valve Consortium

Background

 Patients with low-flow aortic stenosis (LF-AS) have higher mortality than those with high-flow severe AS.  The conventional echocardiographic definition of LF-AS is an indexed stroke volume (SVi) &lt;35ml/m2. Whether this cut-off translates to cardiac magnetic resonance (CMR), and how CMR SVi associates with myocardial remodelling (volume/function/scar) and survival is unclear.

Purpose

 To determine the association between CMR SVi, myocardial remodelling and survival in severe symptomatic AS. 

Methods

  In a multi-centre longitudinal outcome study of patients with severe AS listed for either surgical (SAVR) or transcatheter aortic valve intervention (TAVI) at six cardiothoracic centres, survival was assessed and stratified by SVi. Patients underwent preprocedural echocardiography and CMR between January 2003 and May 2015.  Standardised core-lab analyses on pre-procedural CMR for biventricular volumes, function and scar quantification were performed. All-cause and cardiovascular mortality were tracked for a minimum of two years after AVR.

Results

 A total of 674 patients with severe AS (age 75 ± 14years; 63% male, aortic valve area 0.4 ± 0.1 cm2/m2) were included.  Patients with low SVi by CMR &lt;35ml/m2 were older and had a greater burden of comorbidities (atrial fibrillation [AF], diabetes, high BMI). Independent predictors of SVi were age, AF, increased left atrial volume, aortic valve regurgitant fraction and left ventricular mass (LV) mass index (by CMR). There was no difference in SVi with choice of intervention (TAVI vs SAVR) or presence of late gadolinium enhancement. In multivariate analysis (Table 1), SVi was associated with cardiovascular mortality in the whole cohort (HR 0.97, 95%CI 0.95-0.99, p = 0.02), and all-cause mortality after TAVI (HR 0.97, 95%CI 0.95-0.99, p = 0.006) but not SAVR (p = 0.6). Adjusted mortality hazard increases below 50ml/m2 and plateaus between 35-40ml/m2 (Figure 1A), adjusted for LGE, STS score (Society of Thoracic Surgery score) and wall thickness.

Conclusion

SVi by CMR is an independent predictor of cardiovascular mortality. Mortality hazard increases progressively below a SVi of 50mL/m2.

Abstract Figure 1

UK national and regional trends in cardiovascular magnetic resonance usage – the British Society of CMR survey results

Background

CMR is an imaging modality recommended for multiple indications. Access to CMR is a key issue for its clinical use. We surveyed all CMR units in the UK.

Methods

An online survey of CMR units in the UK, with responses analysed by region and compared with population data.

Results

Response rate was 100% (Table). The UK performed a total of 102,886 scans in 2017, and 117,967 in 2018 representing a 1-year 14.7% increase and a 10-year increase of 573% compared to 2008 data (20,597).By head of population in 2018 there were 1,776 CMR scans per million people, with significant variation nationally and regionally, e.g. 4,256 per million in London vs. 396 per million in Wales (Figure). Mean number of scans per unit was 1,404, (range 98–10,000) with wide variation in referral to diagnostic times (mean 45.7 days, range 5–180) (Figure).

Clinical indications for CMR were: heart failure 21%, cardiomyopathy 27%, function and viability 22%, stress 24%, vascular disease 5%, valvular 5%, myocarditis/pericardial 10%, paediatric /congenital 10%, others e.g. transplant/masses 4%, with overlap. There were 358 consultants reporting CMR in 2018 (234 (65%) cardiologists and 124 (35%) radiologists). 81% of units had a CMR service for patients with pacemakers and defibrillators.

Conclusion

The survey shows the state of CMR in the UK. The 10-year growth has been remarkable, but there are wide disparities in terms of use, access and wait times with potential implications for clinical care. Action is needed to make access equitable across the UK.

Figure 1

Funding Acknowledgement

Type of funding source: None

Stratifying the prognostic capability of cardiovascular magnetic resonance in severe aortic stenosis: a machine learning approach

Background

Cardiovascular magnetic resonance (CMR) demonstrates promise in improving patient risk stratification in aortic stenosis (AS). We explored whether machine learning might provide further insights into the prognostic capability of CMR parameters.

Methods

Severe AS patients (n=440) undergoing AVR were prospectively enrolled across 10 international sites, and CMR performed prior to AVR. A machine learning prediction model using a random survival forest (RSF) was trained with 29 variables, including 13 CMR, 4 echocardiography, and 12 clinical parameters, using post-AVR mortality as an outcome. The impact of the important variables on the outcome (partial dependency) was examined.

Results

The most predictive CMR parameters in the RSF model were the extracellular volume fraction (ECV%), followed by right ventricular ejection fraction (RVEF), late gadolinium enhancement (LGE%), and indexed left ventricular end-diastolic volume (LVEDVi). Regarding the partial effects, the predicted mortality increased strongly once the ECV% exceeded 26.5% (Figure 1A). The LGE% was associated with an increased risk of mortality, which reached a plateau beyond the level of 2% (Figure 1C). There were U-shaped relationships between mortality and both RVEF and LVEDVi, with the lowest mortality seen at RVEF 70% and LVEDVi 68ml/m2 (Figure 1B, D). These trends of predicted outcomes by each variable were verified in the Kaplan-Meier curves and Cox analyses (Table). In both Cox and RSF models, the predictability was substantially increased when these four CMR parameters were added to conventional clinical risk factors. An AS-CMR risk score comprised of these four parameters presented a stepwise increase in mortality with increasing adverse CMR features (p&lt;0.001).

Conclusions

Our machine learning analysis using RSF has identified ECV%, RVEF, LGE%, and LVEDVi as key prognostic markers in severe AS with a nonlinear influence of each parameter on mortality post-AVR.

Figure 1

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): This study was supported by grants from the Korean Health Technology R & D Project, Ministry of Health, Welfare & Family Affairs, Republic of Korea (HI16C0225 and HI15C0399) and the National Institute for Health Research (NIHR) infrastructure at Leeds.

623 Short-term reversed remodeling post aortic valve intervention

Background

LV remodeling in AS can cause LV hypertrophy, interstitial fibrosis and reduced contractility. SAVR or TAVI are the mainstay treatment for symptomatic severe AS. Speckle tracking has the potential to detect early signs of reverse cardiac remodeling but such LV deformation data post-SAVR/TAVI is currently lacking.

Aim

To assess the early impact of LV unloading post-TAVR/SAVR using STE.

Methods

This prospective single-center study recruited 122 patients with varying degrees of AS who underwent resting transthoracic echocardiography with offline speckle-tracking. During the follow-up period, 50 patients underwent TAVI and 15 had SAVR.

Results

Patients were followed-up for a period of 4 ± 2 weeks post-intervention. Table 1 summaries the echocardiographic findings of patients pre- and post-intervention. AV peak velocity and mean pressure gradient dropped significantly immediately after intervention in both groups. AV intervention resulted in early improvements in all myocardial deformation parameters (Figure 1). There was a significant improvement in GLS and GRS irrespective of the intervention type. While SAVR led to a significant early improvement in GCS.

Conclusion

AV Intervention in severe symptomatic AS translates into an immediate and measurable improvement in LV deformation parameters. To our knowledge this is the first echocardiographic evidence of reverse remodeling early after SAVR and TAVI.

Table 1 TAVI (n = 50) SAVR (n = 15) Variables Pre Post P* value Pre Post P* value P value┼ AV vel.(m/s) 4.4 ± 0.8 2.2 ± 0.5 &lt;0.001 4.5 ± 0.8 2.2 ± 0.5 &lt;0.001 NS AV mPG (mmHg) 44.3 ± 16.2 9.7 ± 3.9 &lt;0.001 44.6 ± 19.2 9.8 ± 4.8 &lt;0.001 NS GLS (%) -10.9 ± 3.6 -13.9 ± 3.1 &lt;0.001 -13.7 ± 4.5 -17.7 ± 3.9 0.002 NS GCS (%) -29.2 ± 9.1 -32 ± 9.5 NS -28.6 ± 9.8 -34.9 ± 5.1 0.032 NS GRS (%) 42.0 ± 15.1 47.2 ± 13 0.024 34.7 ± 12.5 41.4 ± 9.9 0.04 NS EDV (ml) 87.29 ± 55.3 89.8 ± 38.6 NS 104.3 ± 25.1 83.2 ± 41.9 NS NS ESV (ml) 45.1 ± 39.4 36.6 ± 29.1 NS 42.8 ± 17.7 28.6 ± 18.6 0.03 NS SV (ml) 59.7 ± 23.6 55 ± 19.3 NS 65.5 ± 17.9 57.2 ± 22.7 NS NS SVi (ml/m2) 33.1 ± 12.7 30.4 ± 9.6 NS 34.1 ± 8.3 29.8 ± 11.1 NS NS LV mass (g) 185.7 ± 53.6 183.3 ± 48. NS 177.5 ± 48.4 169.5 ± 52.2 NS NS LVMi (g/m2) 103.6 ± 30 102.1 ± 25.9 NS 93.8 ± 29.9 89.4 ± 24.2 NS NS Biplane EF (%) 58 ± 15 62 ± 13 0.013 60 ± 9 66 ± 6 &lt;0.05 NS AV: Aortic valve; EDV: end diastolic volume; EF: ejection fraction; ESV: end systolic volume; GCS: Global circumferential strain; GLS: Global longitudinal strain; GRS: Global radial strain; LV: left ventricle; LVMi: left ventricular mass index; mPG: mean pressure gradient; SV: stroke volume; SVi: stroke volume index; Vel: velocity Data are expressed as mean ± SD. Comparisons were performed using paired Student"s t tests(parametric) or Wilcoxon paired test (non-parametric). *Pre and post intervention. ┼Comparison of pre/post-intervention measurement difference between the two intervention groups done using unpaired t-test

Abstract 623 Figure.

P307 Trajectories of Myocardial Strain Across the Spectrum of Aortic Stenosis

Introduction

Optimal timing of intervention in aortic stenosis (AS) is key. Left ventricular deformation parameters are sensitive markers of myocardial wellbeing in AS, but data is sparse so strain does not currently feature in the clinical decision-making process governing timing of AS intervention. We explore the trajectory of myocardial strain in AS of varying severity to potentially identify the most sensitive periods for valve intervention.

Methods

50 patients from across the spectrum of isolated AS were prospectively recruited: mild AS n = 10; moderate AS n = 10; and severe AS n = 30 of which n = 10 in each of 3 ejection fraction (EF) groups: EF &gt; 50%, EF = 40-49% and EF &lt; 35%. Longitudinal, circumferential, and radial strain were measured by speckle tracking echocardiography (STE) using TomTec software.

Results

Strain parameters and EF were not significantly different between mild and moderate AS groups but almost all parameters (except for global circumferential strain (GCS)) showed significant deterioration with progression to severe AS, even in spite of preserved EF (&gt;50%; Table1). In patients with severe AS, strain parameters showed no significant differences between hearts with EF &gt; 50% and EF 40-49%, but they continued to deteriorate significantly (p &lt; 0.05) as hearts transitioned from 40-49% to &lt;35% (Figure 1, a&b).

Conclusion

The heart can maintain its deformation and global systolic function throughout mild and moderate AS but strain deteriorates significantly in severe AS, irrespective of EF. Tracking the precise timings of strain deterioration in severe AS could help refine optimal timings of AS intervention.

LVEF and strain in varying AS severity Left ventricle ejection fraction and strain values in varying severity of AS Mild (n = 10) Moderate (n = 10) Severe (n = 10) P-value Mean (SD) Mean (SD) Mean (SD) EF (%) 65.4 (6.1) 65.8 (9.0) 60.4 (3.6)*§ 0.15 GLS (%) -14.2 (2.1) -13.6 (2.3) -11.8 (2.9)* 0.09 GCS (%) -30.3 (9.1) -31.0 (11.4) -26.5 (8.2) 0.55 GRS (%) 55.9 (15.5) 52.6 (24.0) 35.9 (13.5)*§ 0.05 EF: ejection fraction; GLS: global longitudinal strain; GCS: global circumferential strain; GRS: global radial strain; SD: standard deviation. Severe (n = 10): Severe AS with preserved EF &gt;50%. P-value: ANOVA-single factor; comparison in-between groups was performed using unpaired t-test (parametric) and Mann Whitney test (non-parametric). *significant difference P &lt; 0.05 mild vs severe. §significant difference P &lt; 0.05 moderate vs severe.

Abstract P307 Figure.

618 Adaptive myocardial mechanics in aortic stenosis patients

Introduction

Left ventricular (LV) hypertrophy in aortic stenosis (AS) becomes maladaptive over time, leading first to a reduction in global longitudinal strain (GLS) and in a later stage a reduction in ejection fraction (EF). The myocardial state of impaired GLS but preserved EF is a key remodeling turning point in AS, yet little is known about the coping mechanics of the LV at or around this sensitive juncture.

Aim

1) To study the relationship between LV mass index (LVMi) increase and measures of LV function, including strain in AS; 2) To investigate whether augmentation of global myocardial radial and circumferential strain (GRS, GCS) compensates for the GLS reduction in AS patients with preserved EF.

Methods

One-hundred and eleven patients with varying degrees of AS, and 20 age- and gender-matched healthy volunteers were prospectively enrolled. transthoracic echocardiography with offline strain analysis was performed using TomTec software. Intra- and inter-observer variability of linear LV internal dimensions/thickness, EF and strain indices was tested on 20 randomly selected patients.

Results

Clinical and demographic characteristics of cases and controls are shown in Figure 1. GLS was impaired in AS patients compared to controls. In AS with preserved EF (&gt;50%), as LVMi increased, GLS progressively improved up to a point, beyond which any further increase in LVMi appeared counter-productive with impairment of GLS (Figure 1). EF preservation in these AS patients was mediated by a compensatory supernormal augmentation of GRS and a smaller augmentation of GCS (Figure 1). We observed a significant inverse correlation between GRS and GLS (r = 0.3, p = 0.002), and a similar trend between GCS and GLS (r = 0.275, p = 0.004). Intraclass correlation coefficient was high for all measurements (0.7-0.9).

Conclusion

In patients with AS and preserved EF, progressive myocardial hypertrophy improves GLS up to a point beyond which GLS drops and GRS increase to compensate. This plasticity of myocardial mechanics, in particular the supranormal augmentation of GRS is what enables the pathologically hypertrophied AS ventricle to delay the otherwise inexorable decline in its global systolic function.

Abstract 618 Figure 1

P909Echocardiographic Assessment of Left Ventricular Function in Patients with Aortic Stenosis and the short-term effects after intervention

Introduction

Aortic stenosis (AS) is the most prevalent form of acquired valvular heart disease, it affects ∼2% of people aged over 75. Series of compensatory mechanisms occur, in order for LV to adapt to high pressure overload. Aortic valve replacement has been the mainstay AS treatment either surgically or percutaneously. The evaluation of myocardial strains after Transcatheter Aortic Valve Implantation (TAVI) and Surgical Aortic Valve Replacement (SAVR) is still underexplored and there is no single study to date scouting the difference between TAVI and SAVR.

Aim

To assess the impact of unloading LV after TAVI and SAVR on LV remodelling.

Methods

In this prospective study, we have recruited 111 patients (75±11 years, 63% were females) with varying degrees of aortic stenosis. Of the 111 patients, 43 patients and 11 patients underwent TAVI and SAVR respectively between November 2017 and May 2018. Demographics, clinical and echocardiographic measurements along with speckle tracking parameters were recorded for all participants and again 4±2 weeks after intervention.

Results

Pre-TAVI LV-GLS mean was −10.8±3.5% and after implantation of aortic prosthesis immediate improvement of the myocardial deformation to −13.98±2.9% was observed after one month of the intervention, mean difference of −3.16% following procedure. There was an evidence of significant improvement in LV-GRS after TAVI (44.86±12.9% to 49.77±10.8%, P value= 0.047). Per contra, when comparing pre and post TAVI LV-GCS, no statistical evidence was noted. However, a difference of −2.4% in GCS following the intervention might be clinically important, but no previous evidence can support this. This is attributed to the poor reproducibility and yet not available standardisation.

Table 1 Variables TAVI (n=43) SAVR (n=11) P value† Pre Post P* value Pre Post P* value GLS (%) −10.82±3.5 −13.98±2.9 <0.001 −12.75±4.3 −16.1±2 0.021 0.152 GCS (%) −30.1±8.1 −32.49±9.2 0.134 −27±9.8 −33.9±4.69 0.063 0.062 GRS (%) 44.86±12.9 49.77±10.8 0.047 36.6±13.3 44.97±4.9 0.074 0.058 Data are expressed as mean ± SD. Comparisons were performed using paired Student's t tests. *Pre and post intervention. †Post TAVI vs. post SAVR. Comparison done using unpaired t test of the differences.

Conclusion

Significant improvement was evident in myocardial deformation parameters – in particular GLS – after weeks of the intervention demonstrating a strong evidence of reversed remodelling following SAVR and TAVI.

480Right ventricular dysfunction is associated with late mortality in severe aortic stenosis: results from a multi-centre outcome study in patients undergoing aortic valve replacement

Background

The right ventricle (RV) is relatively understudied and often not routinely assessed in aortic stenosis (AS). However, there are several potential reasons for its importance. RV function is sensitive to left-sided afterload changes which can result in pulmonary hypertension (PH) in severe AS. PH is also a recognised predictor of poor prognosis in AS, but RV afterload and function can be difficult to assess. Cardiovascular magnetic resonance (CMR) may reveal unrecognised RV dysfunction and simultaneously evaluate other prognostic markers in AS.

Purpose

To investigate preoperative RV function assessed by CMR in severe AS and its association with mortality after aortic valve replacement (AVR).

Methods

674 severe AS patients listed for either surgical or percutaneous AVR at six cardiothoracic centres underwent preoperative CMR (for ventricular function, mass and scar) along with echocardiography for valve severity. Scans were core-lab analysed for LV and RV volumes, function and scar quantification. Eight patients were excluded due to inadequate RV image quality for a total of 666 patients finally included. All-cause mortality was tracked for a minimum of 2 years after AVR.

Results

107 (16%) of severe AS undergoing invasive AVR had a RV ejection fraction (RVEF) <55%. CMR detected overt RV dysfunction (RVEF <50%) in 61 (9%) patients. During a median 3.6 years follow-up, 145 (22%) patients died. Baseline RV dysfunction was the most powerful predictor of all-cause mortality (hazard ratio [HR] 2.5, 95% CI 1.6–3.9, p<0.0001). RV function was independent from other clinical characteristics but associated with signs of LV maladaptation (LV ejection fraction [LVEF] and late gadolinium enhancement [LGE]). The strongest Cox multivariable model for all-cause mortality accounted for RV dysfunction, age and LGE (adjusted HRs 1.7, 1.1, 2.2, respectively). Even early stages of pre-procedural RV dysfunction (RVEF 45–50%) were associated with reduced long-term survival.

Cox and Kaplan-Meier for all-cause death

Conclusion

One out of 6 patients with severe AS undergoing valve replacement manifests a reduction in RV function detectable by CMR. Those with RV dysfunction (RVEF<50%) have a 2.5-fold increase in all-cause mortality after AVR at 3.6 years. Whilst RV dysfunction is associated with LV maladaptation (LGE, LVEF), it is a powerful independent factor associated with all-cause mortality and impacts survival even at early stages. Thus, the RV appears to be important in cardiac adaptation to AS and longevity after AS intervention.

Acknowledgement/Funding

British Heart Foundation and National 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.

The risk of cardiac failure following metal-on-metal hip arthroplasty

AIMS

The aim of this study was to determine whether patients with metal-on-metal (MoM) arthroplasties of the hip have an increased risk of cardiac failure compared with those with alternative types of arthroplasties (non-MoM).

PATIENTS AND METHODS

A linkage study between the National Joint Registry, Hospital Episodes Statistics and records of the Office for National Statistics on deaths was undertaken. Patients who underwent elective total hip arthroplasty between January 2003 and December 2014 with no past history of cardiac failure were included and stratified as having either a MoM (n = 53 529) or a non-MoM (n = 482 247) arthroplasty. The primary outcome measure was the time to an admission to hospital for cardiac failure or death. Analysis was carried out using data from all patients and from those matched by propensity score.

RESULTS

The risk of cardiac failure was lower in the MoM cohort compared with the non-MoM cohort (adjusted hazard ratio (aHR) 0.901; 95% confidence interval (CI) 0.853 to 0.953). The risk of cardiac failure was similar following matching (aHR 0.909; 95% CI 0.838 to 0.987) and the findings were consistent in subgroup analysis.

CONCLUSION

The risk of cardiac failure following total hip arthroplasty was not increased in those in whom MoM implants were used, compared with those in whom other types of prostheses were used, in the first seven years after surgery. Cite this article: Bone Joint J 2018;100-B:20-7.