Left atrial morpho-functional changes in hypertrophic cardiomyopathy and Fabry disease: a CMR-feature tracking study

Funding Acknowledgements

Type of funding sources: None.

Background

Left ventricular (LV) diastolic dysfunction (DD) is a hallmark of hypertrophic cardiomyopathy (HCM) and its phenocopies, such as Fabry disease (FD). Together with left atrial (LA) size, LA function is emerging as a sensitive marker of the adaptive changes to backward transmission of LV cardiac filling pressure, thus implementing DD assessment. Additionally, both HCM and FD are characterized by a primitive atrial myopathy, but LA morpho-functional changes in HCM and FD have never been directly compared. More recently, LA strain by Cardiovascular Magnetic Resonance Feature Tracking (CMR-FT) has been demonstrated to be a feasible and reproducible tool to explore LA function.

Purpose

To compare LA morpho-functional changes in HCM and FD and to explore their correlation with tissue alterations.

Methods

15 HCM and 15 sex-, age- and LV mass index-matched FD patients underwent CMR (Magnetom Aera 1.5T, Siemens) and Doppler Echocardiography for LV diastolic function assessment (E/e’ and DD grading from 0 to 3). LA phasic function was evaluated by CMR-FT strain (Qstrain Medis). The software output included passive (εe, conduit function), active (εa, booster pump function) and total strain (εs, reservoir function), along with LA volumes and ejection fraction (EF). Late gadolinium enhancement (LGE) was quantified as a percentage of LV mass using the standard deviations (SDs) method (≥ 5 SDs). Interstitial fibrosis was assessed by extracellular volume (ECV) quantification in remote myocardium. All patients were in sinus rhythm.

Results

In the HCM group, the proportion of patients with DD grade 2-3 was only slightly higher than in FD (p 0.26). Accordingly, no significant difference was found in E/e’ value (p 0.78). Compared to FD, HCM patients showed more severe LA morpho-functional changes, including larger LA end-systolic volume (ESV) (113 ± 35 vs 84 ± 23 ml), lower LA EF (37 ± 7 vs 44 ± 9 %) and a greater reduction of εs (-20 ± 5 vs -25 ± 6 %) and εa (-10 ± 4 vs -15 ± 4 %) (all p < 0.05). LV size and function and the burden of fibrosis (LGE quantification and ECV) were comparable between the two groups. Interestingly, in HCM population, unlike in FD, LA morpho-functional measurements significantly correlated with tissue characterization parameters (LA ESV with LGE, r 0.56, p 0.03; εs and εa with ECV, r -0.51, p 0.05 and r -0.59, p 0.02, respectively).

Conclusions

LA morpho-functional alterations are much more severe in HCM compared to FD with similar degree of LV hypertrophy. A more severe atrial myopathy or different mechanisms of atrial damage in the two cardiomyopathies may explain these findings. LA CMR-FT analysis may represent a sensitive tool to discriminate between HCM and FD, although larger studies are needed to confirm this finding and the possible correlation with the occurrence of atrial arrhythmias and thromboembolic risk.

Late gadolinium enhancement predicts adverse clinical outcome in patients with mitral valve prolapse/mitral annulus disjunction

Funding Acknowledgements

Type of funding sources: None.

OnBehalf

Mitral vAlve prolapse and disjunction by cardiac maGnetIC resonance (MA-GIC) registry

Backgroung

Mitral valve prolapse (MVP) is 2-3% prevalent in the general population with good prognosis. However, some patients develop complex ventricular arrhythmias (CVAs), sudden cardiac death (SCD), or severe mitral regurgitation (MR). Previous studies suggested that bi-leaflet involvement, mitral annulus disjunction (MAD), and myocardial fibrosis (MF) are associated with adverse outcome. Notwithstanding, these findings were limited to autopsic series or single-centre studies involving highly selected patients. Moreover, MF has been scantly investigated as predictor of clinical outcome.

Purpose

To investigate the prognostic significance of MF in an international multicentre study of MVP patients studied by cardiovascular magnetic resonance (CMR) with late gadolinium enhancement (LGE). 

Methods

From October 2007 to June 2020 patients undergoing LGE-CMR were screened in 14 European centres. Inclusion criteria were: i) age > 18 years; ii) full clinical history and cardiac rhythm monitoring at baseline; iii) MVP (leaflet displacement ≥ 2 mm beyond the annulus). Exclusion criteria were: i) ischemic heart disease; ii) primary cardiomyopathy; iii) inflammatory heart disease; iv) congenital heart diseases; v) moderate-to-severe valvular heart disease. CVAs at the study outset was defined as one of the following: i) ventricular ectopic beats >10000/24h; ii) ≥ 1 episode of non-sustained ventricular tachycardia (VT); iii) sustained VT; iv) aborted SCD. Primary end-point was a composite of SCD, unexplained syncope, and mitral valve repair/replacement. Secondary end-point was a composite of SCD and unexplained syncope. 

Results

Four-hundred-fifty-eight MVP patients were eventually included (46 ± 16 years old, 51% males) of whom 68% had MAD. LGE was detected in 103 (22%) of subjects with mid-wall pattern (46%) in left ventricular (LV) lateral wall (66%) as the most prevalent feature. At baseline, 37% of LGE-positive patients vs. 18% of LGE-negative individuals had CVAs (P < 0.001). SVT and/or aborted SCD were more prevalent in LGE-positive than in LGE-negative patients (9% vs 2%, P < 0.001). By multivariable Cox-regression analysis, LGE presence or extent were strong independent predictors of the primary (HR = 4.02, P = 0.003 and HR = 4.76 per 10% increase, P = 0.032, respectively) and secondary (HR = 5.39, P = 0.008 and HR = 8.78 per 10% increase, P = 0.012, respectively) endpoints after correction for major confounders including LV volumes, left atrial size and MAD presence.

Conlusion

Myocardial fibrosis by LGE is the strongest independent predictor of clinical outcome in MVP. In contrast, MAD per se does not harbinger worse prognosis.

Left atrial strain analysis in hypertensive heart disease and hypertrophic cardiomyopathy by cardiovascular magnetic resonance feature tracking

Funding Acknowledgements

Type of funding sources: None.

Background

Increasing evidence suggests that left atrial (LA) deformation is a sensitive marker of diastolic dysfunction in hypertrophic phenotypes. However, there is little data about the impact of hypertension on LA function; furthermore, LA deformation in hypertensive heart disease (HHD) and hypertrophic cardiomyopathy (HCM) has not been compared yet. 

Purpose

The aim of this study is to compare atrial dimensions and function, evaluated by cardiovascular magnetic resonance feature tracking (CMR-FT) in patients with HHD, HCM and healthy subjects (HS).

Methods

67 patients (20 HHD, 27 HCM, 20 HS) underwent CMR and were included in the study. Patients were matched for age, sex and BSA; HHD and HCM were also comparable for LV mass index and ejection fraction (EF). CMR-FT atrial strain analysis was performed using Qstrain, Medis software to obtain i) LA conduit function, ii) LA booster pump function), iii) LA reservoir function, iv) LA volumes and EF. Tissue Doppler echocardiography was used to assess diastolic function, including E/e’. LA stiffness was calculated as the ratio between E/e’ and LA reservoir.

Both focal and interstitial myocardial fibrosis were assessed with LGE and extracellular volume (ECV) quantification. 

Results

HHD and HCM showed impaired LA reservoir, conduit function and higher LA volumes vs HS (reservoir: 28 ± 11% and 28 ± 13% vs 41 ± 17%; conduit: 13 ± 7% and 13 ± 7% vs 22 ± 11%; LAESV: 76 ± 21 and 87 ± 22 vs 57 ± 19 ml respectively; all p ≤ 0.03).

HHD and HCM were comparable for bi-ventricular morpho-functional parameters and ECV. HHD showed lower E/e’ values (8 ± 2 vs 16 ± 7, p = 0.002) and LA stiffness (0.23 ± 0.3 vs 0.74 ± 0.6, p 0.03), LA dimensions (LA area 13 ± 3 vs 16 ± 3 cm2/m2, p = 0.02 , LAESVi 41 ± 12 vs 48 ± 11 ml/m2, p = 0.05) and LGE extent (1 ± 2% vs 5 ± 5%, p = 0.001) as compared to HCM. Interestingly, HHD revealed a comparable reduced LA reservoir and conduit function (all p = 0.9) vs HCM. 

In HHD patients LA reservoir function was correlated with E/e’ (r -0.8, p = 0.02), but not in HCM. Conversely, LA reservoir function was correlated with LV mass index in HCM (r -0.5, p < 0.01). 

Conclusions

HHD patients showed a similar and significant impairment of LA function, with lower LA dimensions and E/e’ compared to HCM with similar LV mass index and preserved function.

CMR-FT atrial strain analysis could represent a useful tool for HHD management, able to detect diastolic dysfunction (and/or atrial dysfunction) earlier than traditional markers. Further studies are needed to explore the relationship of LA deformation to heart failure symptoms and atrial fibrillation occurrence and potential changes related to response to therapy.

Cardiovascular magnetic resonance: What clinicians should know about safety and contraindications

Cardiovascular magnetic resonance (MR) is a multiparametric, non-ionizing, non-invasive imaging technique, which represents the imaging gold standard to study cardiac anatomy, function and tissue characterization. Faced with a wide range of clinical application, in this review we aim to provide a comprehensive guide for clinicians about MR safety, contraindications and image quality. Starting from the physical interactions of the static magnetic fields, gradients and radiofrequencies with the human body, we will describe the most common metal and electronic devices which are allowed (MR-safe), allowed under limited conditions (MR-conditional) or contraindicated (MR-unsafe). Moreover, some conditions potentially affecting image quality and patient comfort will be mentioned, including arrhythmias, claustrophobia, and poor breath-hold capacity. Finally, we will discuss the pharmacodynamics and pharmacokinetics of current gadolinium-based contrast agents, their contraindications and their potential acute and chronic adverse effects, as well as the safety issue concerning the use of vasodilating/inotropic agents in stress cardiac MR.

4D flow evaluation of blood non-Newtonian behavior in left ventricle flow analysis

Blood is generally modeled as a Newtonian fluid, assuming a standard and constant viscosity; however, this assumption may not hold for the highly pulsatile and recirculating intracavitary flow in the left ventricle (LV), hampering the quantification of fluid dynamic indices of potential clinical relevance. Herein, we investigated the effect of three viscosity models on the patient-specific quantification of LV blood energetics, namely on viscous energy loss (EL), from 4D Flow magnetic resonance imaging: I) Newtonian with standard viscosity (3.7 cP), II) Newtonian with subject-specific hematocrit-dependent viscosity, III) non-Newtonian accounting for the effect of hematocrit and shear rate. Analyses were performed on 5 controls and 5 patients with cardiac light-chain amyloidosis. In Model II, viscosity ranged between 3.0 (-19%) and 4.3 cP (+16%), mildly deviating from the standard value. In the non-Newtonian model, this effect was emphasized: viscosity ranged from 3.2 to 6.0 cP, deviating maximally from the standard value in low shear rate (i.e., <100 s^-1) regions. This effect reflected on EL quantifications: in particular, as compared to Model I, Model III yielded markedly higher EL values (up to +40%) or markedly lower (down to -21%) for subjects with hematocrit higher than 39.5% and lower than 30%, respectively. Accounting for non-Newtonian blood behavior on a patient-specific basis may enhance the accuracy of intracardiac energetics assessment by 4D Flow, which may be explored as non-invasive index to discriminate between healthy and pathologic LV.

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

The alcohol-induced cardiomyopathy: A cardiovascular magnetic resonance characterization

BACKGROUND

Alcoholic cardiomyopathy(ACM) is part of the non-ischaemic dilated cardiomyopathy(NI-DCM) spectrum. Little is known about cardiovascular magnetic resonance(CMR) features in ACM patients. The aim of this study is to describe CMR findings and their prognostic impact in ACM patients.

METHODS

Consecutive ACM patients evaluated in five referral CMR centres from January 2005 to December 2018 were enrolled. CMR findings and their prognostic value were compared to idiopathic NI-DCM(iNI-DCM) patients. The main outcome was a composite of death/heart transplantation/life-threatening arrhythmias.

RESULTS

Overall 114 patients (52 with ACM and 62 with iNI-DCM) were included. ACM patients were more often males compared to iNI-DCM (90% vs 64%, respectively, p ≤ 0.001) and were characterized by a more pronounced biventricular adverse remodelling than iNI-DCM, i.e. lower LVEF (31 ± 12% vs 38 ± 11% respectively, p = 0.001) and larger left ventricular end-diastolic volume (116 ± 40 ml/m² vs 67 ± 20 ml/m² respectively, p < 0.001). Similarly to iNI-DCM, late gadolinium enhancement (LGE), mainly midwall, was present in more than 40% of ACM patients but, conversely, it was not associated with adverse outcome(p = 0.15). LGE localization was prevalently septal (87%) in ACM vs lateral in iNI-DCM(p < 0.05). Over a median follow-up of 42 months [Interquartile Range 24-68], adverse outcomes were similar in both groups(p = 0.67).

CONCLUSIONS

ACM represents a specific phenotype of NI-DCM, with severe morpho-functional features at the onset, but similar long-term outcomes compared to iNI-DCM. Despite the presence and pattern of distribution of LGE was comparable, ACM and iNI-DCM showed a different LGE localization, mostly septal in ACM and lateral in iNI-DCM, with different prognostic impact.

Trabecular complexity as an early marker of cardiac involvement in Fabry disease

AIMS

Fabry cardiomyopathy is characterized by glycosphingolipid storage and increased myocardial trabeculation has also been demonstrated. This study aimed to explore by cardiac magnetic resonance whether myocardial trabecular complexity, quantified by endocardial border fractal analysis, tracks phenotype evolution in Fabry cardiomyopathy.

METHODS AND RESULTS

Study population included 20 healthy controls (12 males, age 32±9) and 45 Fabry patients divided into three groups: 15 left ventricular hypertrophy (LVH)-negative patients with normal T1 (5 males, age 28±13; Group 1); 15 LVH-negative patients with low T1 (9 males, age 33±9.6; Group 2); 15 LVH-positive patients (11 males, age 53.5±9.6; Group 3). Trabecular fractal dimensions (Dfs) (total, basal, mid-ventricular, and apical) were evaluated on cine images. Total Df was higher in all Fabry groups compared to controls, gradually increasing from controls to Group 3 (1.27±0.02 controls vs. 1.29±0.02 Group 1 vs. 1.30±0.02 Group 2 vs. 1.34±0.02 Group 3; P<0.001). Group 3 showed significantly higher values of all Dfs compared to the other Groups. Both basal and total Dfs were significantly higher in Group 1 compared with controls (basal: 1.30±0.03 vs. 1.26±0.04, P =0.010; total: 1.29±0.02 vs. 1.27±0.02, P=0.044). Total Df showed significant correlations with: (i) T1 value (r=-0.569; P<0.001); (ii) LV mass (r=0.664, P<0.001); (iii) trabecular mass (r=0.676; P <0.001); (iv) Mainz Severity Score Index (r=0.638; P<0.001).

CONCLUSION

Fabry cardiomyopathy is characterized by a progressive increase in Df of endocardial trabeculae together with shortening of T1 values. Myocardial trabeculation is increased before the presence of detectable sphingolipid storage, thus representing an early sign of cardiac involvement.

Right ventricular functional changes detected by CMR during ajmaline challenge in patients with Brugada syndrome

Background

3D echocardiography has recently revealed alterations of right ventricular (RV) function in Brugada syndrome (BrS) during ajmaline challenge (AC). Cardiac magnetic resonance (CMR) is the gold standard for functional and anatomical RV assessment. CMR feature-tracking (FT) analysis is able to detect subtle functional changes in the underlying myocardial substrate.

Purpose

To investigate RV functional changes during AC in BrS patients using CMR-FT analysis.

Methods

24 consecutive BrS and 28 matched controls underwent CMR. CMR protocol included paraxial and parasagittal cine bSSFP sequences, acquired before and 2÷5 minutes after ajmaline infusion (1 mg/kg in 5 minutes), to obtain a comprehensive evaluation of the RV free wall. All patients were closely monitored with ECG. Semi-automatic threshold-based quantification of ventricular volumes, function and mass was performed in QMass. CMR-FT analysis of RV function was performed in QStrain. Values of longitudinal strain (LS) and transverse displacement (TD) of the RV wall before and after AC were compared in BrS patients and in the control group.

Results

AC induced Type 1 ECG pattern in all BrS patients and no ECG changes in controls. In BrS patients TD of the RV free wall was significantly reduced (P≤0.003) at peak ajmaline effect; controls reported sub-millimetric TD changes. LS of the RV wall was significantly impaired in BrS patients (P&lt;0.0001) on both b SSFP sequences; LS remained comparable (P=0.62) in controls on the parasagittal sequence; minor but not negligible (P=0.01) LS changes were noticed on the paraxial stack. (Table 1)

Conclusions

In patients with BrS CMR-FT analysis during AC unveils dysfunctional RV wall mechanics in areas generally associated with abnormal electrical activity.

TD and LS in a Brs patient post AC

Funding Acknowledgement

Type of funding source: None

Quantitative 4D Flow CMR analysis of intracardiac blood flow energetics in ischemic cardiomyopathy patients

Background

Ischemic cardiomyopathy (ICM) is often associated with negative LV remodelling after myocardial infarction, sometimes resulting in impaired LV function and dilation (iDCM). 4D Flow CMR has been recently exploited to assess intracardiac hemodynamic changes in presence of LV remodelling.

Purpose

To quantify 4D Flow intracardiac kinetic energy (KE) and viscous energy loss (EL) and investigate their relation with LV dysfunction and remodelling.

Methods

Patients with prior anterior myocardial infarction underwent a CMR study with 4D Flow sequences acquisition; they were divided into ICM (n=10) and iDCM (n=10, EDV&gt;208 ml and EF&lt;40%). 10 controls were used for comparison. LV was semi-automatically segmented using short axis CMR stacks and co-registered with 4D Flow. Global KE and EL were computed over the cardiac cycle. NT-proBNP measurements were correlated with average and peak values, during systole and diastole.

Results

Both LV volume and EF significantly differ (P&lt;0.0001) between iDCM (EDV=294±56 ml, EF=24±8%), ICM (EDV=181±32 ml, EF=34±6%) and controls (EDV=124±29 ml, EF=72±5%). If compared to controls, both ICM and iDCM showed significantly lower KE (P≤0.0008); though lower than controls, EL was higher in iDCM than ICM. Within the iDCM subgroup, diastolic mean KE and peak EL reported good inverse correlation with NT-proBNP (r=−0.75 and r=−0.69, respectively). EL indexed (ELI) to average KE during systole was higher in the entire ischemic group as compared to controls (ELI(ischemic) = 0.17 vs. ELI(controls) = 0.10, P=0.0054).

Conclusions

4D Flow analyses effectively mapped post-ischemic LV energetic changes, highlighting the disproportionate intraventricular EL relative to produced KE; preliminary good correlation between LV energetic changes and NT-proBNP will deserve further investigation in order to contribute to early detection of heart failure.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): Italian Ministry of Health

Increased remote extracellular volume measured by CMR T1 mapping allows early identification of left atrial dysfunction in hypertrophic cardiomyopathy

Background

Myocardial fibrosis is a hallmark of hypertrophic cardiomyopathy (HCM). Cardiac magnetic resonance (CMR) detects replacement fibrosis (RF) through late gadolinium enhancement (LGE) and interstitial fibrosis (IF) in apparently unscarred myocardium by T1 mapping-derived increased extracellular volume (ECV). Differently from LGE, to date only few small studies have explored the clinical significance of IF in HCM and a correlation between IF and diastolic dysfunction (DD) has been proposed. However, DD detection is challenging in this population since the accuracy of standard echocardiographic parameters is controversial, especially in presence of left ventricular outflow tract obstruction (LVOTO). Left atrial (LA) dysfunction is associated with high left ventricular (LV) filling pressures and may represent an early marker of DD in HCM.

Purpose

To explore the correlation between IF and LA dysfunction in HCM patients with preserved systolic function.

Methods

93 consecutive HCM patients with preserved EF underwent a standard CMR scan. Semi-automatic threshold-based quantification of ventricular volumes, function and mass was performed. LA volumes (LAV) and function were evaluated by CMR feature-tracking (FT) analysis. The three atrial phasic functions were analyzed: (i) passive strain (εe), (ii) active strain (εa) and (iii) total strain (εs). LGE was quantified using the standard deviations (SDs) method (≥4 SDs). IF was assessed by T1 mapping-derived ECV quantification in remote myocardium (r-ECV). A matched group of 15 healthy subjects (HS) served as controls.

Results

Compared to HS, HCM patients showed increased LAV (LAV max: HS 39±9ml, HCM 59±20 ml; LAV min: HS 16±4 ml, HCM 34±17 ml; p&lt;0.001), reduced LA EF (HS 61±3%, HCM 45±12%, p&lt;0.001), impaired εs (HS 40±7%, HCM 29±11%, p&lt;0.001) and εe (HS 26±7%, HCM 15±7%, p&lt;0.001). No differences in εa were observed (HS 13±4%, HCM 14±7%, p 0.56). HCM patients were divided into 2 groups according to the presence of IF, defined as r-ECV values ≥29%. The two ECV groups did not differ in terms of LV EF, LA EF, LAV, LA area, E/E', LGE, LV mass, maximal wall thickness and LVOTO (all p&gt;0.05). HCM patients with increased r-ECV showed significantly impaired LA function in terms of all three strain parameters vs. normal r-ECV group (HCM r-ECV &lt;29%: εs 31±12%, εe15±7%, εa 15±5%; HCM r-ECV≥29%: εs 24±7%, εe 12±4%, εa 12±5%; all p&lt;0.05).

Conclusions

In HCM patients increased r-ECV correlates with LA dysfunction, hinting towards a possible role for IF in determining altered LV relaxation and DD.

LA strain in controls and HCM ECV groups

Funding Acknowledgement

Type of funding source: None

Anomalous aortic origin of coronary artery biomechanical modeling: Toward clinical application

OBJECTIVES

Anomalous aortic origin of the coronary artery can be associated with sudden cardiac death and ischemic events. Anatomic static characteristics mainly dictated surgical indications, although adverse events are usually related to dynamic physical effort. We developed a computational model able to simulate anomalous coronary behavior, and we aimed to assess its clinical applicability and to investigate coronary characteristics at increasing loading stress conditions.

METHODS

We selected 5 patients with anomalous aortic origin of the coronary artery and 5 control subjects. For each of them, we construct a 3-dimensional model resembling the aortic root and coronary arteries based on 25 parameters obtained from computed tomography. Structural finite element analysis simulations were run to simulate pressure increasing in the aortic root during exercise (+40 mm Hg, +100 mm Hg with respect baseline condition, assumed at 80 mm Hg) and investigate coronary lumen characteristics.

RESULTS

The 25 parameters were obtainable in all subjects with a consistent interobserver agreement. In control subjects, the right coronary artery had a more significant lumen expansion at loading conditions compared with anomalous aortic origin of coronary artery (6%-19.2% vs 1.8%-8.1%, P = .008), which also showed an inability to expand within the intramural segment.

CONCLUSIONS

The proposed anomalous aortic origin of coronary artery model is able to represent the pathogenic disease mechanism after being populated with patient-specific data. It can assess the impaired expansion of anomalous right coronary at loading conditions, a process that cannot be quantified in any clinical set-up. This first clinical application showed promising results on quantifying pathological behavior, potentially helping in patient-specific risk stratification.

Predictors of Clinical Evolution in Prehypertrophic Fabry Disease

BACKGROUND

In prehypertrophic Fabry disease, low myocardial T1 values, reflecting sphingolipid storage, are associated with early structural and ECG changes. The correlations between T1 values and functional parameters have not been explored. Furthermore, the potential prognostic role of T1 in predicting disease worsening is still unknown.

METHODS

ECG, 2D echocardiography, cardiopulmonary test, and cardiac magnetic resonance were performed in 44 Fabry patients without left ventricular hypertrophy (35.7±14.5 years, 68.2% females). After a 12-month follow-up, clinical stability was evaluated using Fabry Stabilization Index.

RESULTS

At baseline, T1 values showed a negative correlation with left ventricular mass ( r=-0.79; P<0.0001), maximum wall thickness ( r=-0.79; P<0.0001), Sokolow-Lyon Index ( r=-0.54; P<0.0001), left atrial volume ( r=-0.49; P<0.0002), and Mainz Severity Score Index ( r=-0.61; P<0.0001). No significant differences in systo-diastolic function and exercise capacity were observed comparing normal and low T1 Fabry patients. Arrhythmias were reported in 2 females with low T1 and late gadolinium enhancement. Five patients (40.0±12.4 years, 2 females) showed clinical worsening (Fabry Stabilization Index >20%) at follow-up. Higher left ventricular wall thickness (odds ratio, 2.61; CI, 1.04-6.57; P=0.04), left atrial volume (odds ratio, 1.24; CI, 1.02-1.51; P=0.03), and lower T1 values (odds ratio, 0.98; CI, 0.96-0.99; P=0.03) at baseline were independently associated with clinical worsening at follow-up.

CONCLUSIONS

In prehypertrophic Fabry disease, low T1 values correlate with early electrocardiographic, morphological cardiac changes, and worsening of global disease severity but are not associated with functional abnormalities. The presence of low T1 values is a risk factor for disease worsening, thus representing a potential new tool in prognostic stratification and therapeutic approach.

Reliability of single breath hold three-dimensional cine kat-ARC for the assessment of biventricular dimensions and function

PURPOSE

To assess the accuracy and reproducibility of 3D-cine k-adaptative-t-autocalibrating reconstruction for cartesian sampling (3D cine kat-ARC) for quantification of biventricular volumes, ejection fraction and LV mass in clinical practice.

METHOD

74 patients underwent cardiac magnetic resonance for clinical indications. In the whole population 3D cine kat-ARC and 2D cine bSSFP images were acquired on short axis view. Subsequently, the population was divided in three subgroups (dilated, hypetrophic, other phenotypes). Two experienced observers performed analysis of volumes, biventricular function and left ventricular mass in the overall population and subgroups using an off-line workstation. Statistical analysis was performed using Student's t-test, linear regression and Bland-Altman plot, correlation coefficient η2 and the intraclass correlation coefficient (ICC). A cut-off value of p < 0.05 was considered statistically significant.

RESULTS

Biventricular volumes, function and left ventricular mass evaluated with 3D cine kat-ARC sequences did not show any significant difference compared to 2D bSSFP sequences in the overall population (p > 0.05). Bland-Altman analysis showed limited bias and narrow limits of the agreement for all measurements in overall population. Subgroup analysis showed a statistically significant difference (p = 0.04) for left ventricular ejection fraction (LVEF) in patients with a dilated phenotype; showing a minimum overestimation tendency for 3D cine kat ARC (2D cine bSSFP LVEF = 46.44 ± 15.83% vs 3D cine kat-ARC LVEF = 48.36 ± 16.50 %).

CONCLUSIONS

3D cine kat-ARC 3D sequences allow an accurate evaluation of biventricular volumes and function in a single breath hold.

Sex differences in left ventricular remodelling, myocardial fibrosis and mortality after aortic valve replacement

OBJECTIVES

To investigate sex differences in left ventricular remodelling and outcome in patients undergoing surgical or transcatheter aortic valve replacement (SAVR/TAVR).

METHODS

In this multicentre, observational, outcome study with imaging core-lab analysis, patients with severe aortic stenosis (AS) listed for intervention at one of six UK centres were prospectively recruited and underwent cardiovascular magnetic resonance imaging. The primary endpoint was all-cause mortality and secondary endpoint was cardiovascular mortality.

RESULTS

674 patients (425 men, 249 women, age 75±14 years) were included: 399 SAVR, 275 TAVR. Women were older, had higher surgical risk scores and underwent TAVR more frequently (53% vs 33.6%, p<0.001). More men had bicuspid aortic valves (BAVs) (26.7% vs 14.9%, p<0.001) and demonstrated more advanced remodelling than women. During a median follow-up of 3.6 years, 145 (21.5%) patients died, with no significant sex difference in all-cause mortality (23.3% vs 20.5%, p=0.114), but higher cardiovascular mortality in women (13.7% vs 8.5%, p=0.012). There were no significant sex-related differences in outcome in the SAVR or TAVR subgroups, or after excluding those with BAV. Factors independently associated with all-cause mortality were age, left ventricular ejection fraction (LVEF), BAV (better) and myocardial fibrosis detected with late gadolinium enhancement (LGE) in men, and age, LVEF and LGE in women. Age and LGE were independently associated with cardiovascular mortality in both sexes.

CONCLUSIONS

Men demonstrate more advanced remodelling in response to a similar severity of AS. The higher cardiovascular mortality observed in women following AVR is accounted for by women having less BAV and higher risk scores resulting in more TAVR. LGE is associated with a worse prognosis in both sexes.

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

P5273Trabecular complexity as a subclinical structural alteration in Fabry cardiomyopathy: a cardiac magnetic resonance study

Background

Heart involvement represents the main cause of death in Fabry Disease (FD), thus its early detection is important to define the optimal therapeutic strategy. Recently, a disproportionate increase in myocardial trabeculation has been described in FD by cardiac magnetic resonance (CMR), even in early (prehypertrophic) stage of the disease. In addition, CMR with T1 mapping can identity the presence of myocardial sphingolipid storage (causing lowering of native T1 values) in more than 50% of FD patients with no LVH. However, it is not clear whether a relationship exists between trabecular complexity and sphingolipid storage in FD.

Aim

To explore the association between myocardial trabecular complexity, quantified by endocardial border fractal analysis, and sphingolipid storage, described by CMR T1 mapping, in different stages of Fabry cardiomyopathy.

Methods

Study population included 60 subjects: 15 FD patients with no detectable signs of cardiac involvement (no LVH, normal T1; 2 M, age 30.6±14; Group 1); 15 FD patients with early sphingolipid storage (no LVH, low T1; 9 M, age 33±9.6; Group 2); 15 FD patients with LVH (11 M, age 53.5±9.6; Group 3); 15 healthy controls (9 M, age 34±10). Patients and controls underwent CMR with T1 mapping; disease severity was quantified using Mainz Severity Score Index (MSSI). Myocardial trabecular fractal dimension was evaluated, blinded to patients'characteristics, on short axis cine images using the Image J dedicated plug-in FracLac, deriving the following parameters: total, basal, mid-ventricular and apical fractal dimensions.

Results

Total fractal dimension was higher in all Fabry groups compared to controls. Indeed, a gradient of total fractal dimension was observed, with this parameter gradually increasing from healthy controls to Groups 3 (1.27±0.02 in controls vs 1.29±0.02 in Group 1 vs 1.30±0.02 in Group 2 vs 1.34±0.02 in Group 3; p<0.001) (Figure 1A). Interestingly, both total and basal fractal dimensions were significantly higher in Group 1 compared to controls (1.27±0.02 vs 1.29±0.02, p=0.044 and 1.26±0.04 vs 1.30±0.03; p=0.007, respectively). Moreover, considering the total population, fractal dimension showed significant correlations with: i) T1 values (r=−0.567; p<0.001 - Figure 1B); ii) LV mass (r=0.674, p<0.001); iii) trabecular mass expressed as percentage of global LV mass (r=0.611; p<0.001); iv) MSSI (r=0.535; p<0.001).

Conclusion

Cardiac involvement in FD is characterized by a progressive increase in fractal dimension of endocardial trabeculae (Figure 1C). Both total and basal myocardial trabeculation are increased in Fabry patients even before the presence of detectable sphingolipid storage, thus representing a very early sign of cardiac involvement.

Myocardial Scar and Mortality in Severe Aortic Stenosis

Supplemental Digital Content is available in the text.

Background:

Aortic valve replacement (AVR) for aortic stenosis is timed primarily on the development of symptoms, but late surgery can result in irreversible myocardial dysfunction and additional risk. The aim of this study was to determine whether the presence of focal myocardial scar preoperatively was associated with long-term mortality.

Methods:

In a longitudinal observational outcome study, survival analysis was performed in patients with severe aortic stenosis listed for valve intervention at 6 UK cardiothoracic centers. Patients underwent preprocedural echocardiography (for valve severity assessment) and cardiovascular magnetic resonance for ventricular volumes, function and scar quantification between January 2003 and May 2015. Myocardial scar was categorized into 3 patterns (none, infarct, or noninfarct patterns) and quantified with the full width at half-maximum method as percentage of the left ventricle. All-cause mortality and cardiovascular mortality were tracked for a minimum of 2 years.

Results:

Six hundred seventy-four patients with severe aortic stenosis (age, 75±14 years; 63% male; aortic valve area, 0.38±0.14 cm²/m²; mean gradient, 46±18 mm Hg; left ventricular ejection fraction, 61.0±16.7%) were included. Scar was present in 51% (18% infarct pattern, 33% noninfarct). Management was surgical AVR (n=399) or transcatheter AVR (n=275). During follow-up (median, 3.6 years), 145 patients (21.5%) died (52 after surgical AVR, 93 after transcatheter AVR). In multivariable analysis, the factors independently associated with all-cause mortality were age (hazard ratio [HR], 1.50; 95% CI, 1.11–2.04; P=0.009, scaled by epochs of 10 years), Society of Thoracic Surgeons score (HR, 1.12; 95% CI, 1.03–1.22; P=0.007), and scar presence (HR, 2.39; 95% CI, 1.40–4.05; P=0.001). Scar independently predicted all-cause (26.4% versus 12.9%; P<0.001) and cardiovascular (15.0% versus 4.8%; P<0.001) mortality, regardless of intervention (transcatheter AVR, P=0.002; surgical AVR, P=0.026 [all-cause mortality]). Every 1% increase in left ventricular myocardial scar burden was associated with 11% higher all-cause mortality hazard (HR, 1.11; 95% CI, 1.05–1.17; P<0.001) and 8% higher cardiovascular mortality hazard (HR, 1.08; 95% CI, 1.01–1.17; P<0.001).

Conclusions:

In patients with severe aortic stenosis, late gadolinium enhancement on cardiovascular magnetic resonance was independently associated with mortality; its presence was associated with a 2-fold higher late mortality.