Cardiac amyloidosis is not a single disease: a multiparametric comparison between the light chain and transthyretin forms

Background

Systemic amyloidoses represent a heterogeneous group of diseases resulting from the deposition of misfolded proteins as amyloid fibrils into the extracellular matrix of different organs. Based on this precursor protein, cardiac amyloidosis (CA) can be most frequently classified as: light chain (AL) and transthyretin (ATTR) amyloidosis, with different management and prognosis.

Purpose

The purpose of this study is to establish a differential diagnosis algorithm targeted towards these two most frequent subtypes of CA. Although confirmation through invasive or non-invasive diagnostic algorithms is still mandatory for a final diagnosis, a series of clinical, paraclinical and imaging differences could possibly guide the choice for more complex diagnostic steps.

Methods

We prospectively included all consecutive patients with ATTR and AL evaluated between 2018 and 2022 in our center. All patients had a complete clinical, paraclinical and imaging evaluation including myocardial deformation study, and confirmation of the final diagnosis, according to the current international recommendations.

Results

The study population included 81 patients divided into 2 groups: ATTR (group 1, n=32: 30 variant and 2 wild type) and AL (group 2, n=49).

ATTR patients were younger (50.7±13.9 vs. 60.2±7.3 years, p=0.0001), had predominantly more neurological symptoms, milder cardiac symptoms and lower values of cardiac biomarkers than AL: NT-proBNP (3095±4433 vs. 10382±9008 ng/ml, p=0.001) and high sensitive troponin I (0.0129±0.01 vs 0.177±0.2 ng/ml, p=0.0002), with better renal function (mean GFR 84.74±26.9 vs. 64.5±29.45 mL/min, p=0.003). We found no significant differences in terms of ECG changes.

Moreover, at similar left ventricular (LV) wall thickness and ejection fraction, ATTR group had less pericardial effusions (53.6 vs. 86.8%, p=0.0027), better LV global longitudinal strain (−12.0±3.7 vs. −9.7±4.6%, p=0.03), RV strain (RVFW strain −19.7±6.2 vs. −14.5±11.0%, p=0.03) and also better reservoir and contractile function of the LA (LASr 17.2±12.3 vs. 11.2±7.4%, p=0.02).

Based on this multiparametric comparison we proposed a prediction algorithm to differentiate between the 2 forms of CA. A score of equal or more than 4 from a maximum of 9 points, has been able to differentiate between AL and ATTR with a sensitivity and specificity of 78 and 80%, respectively; AUC= 0.82.

Conclusions

CA is a complex entity and requires extensive testing through serum biomarkers, imaging, and invasive confirmation of amyloid infiltration in some cases. This study highlighted a series of non-invasive checkpoints, which can be useful in guiding the decision making process towards a more accurate and rapid differential diagnosis, in cases where a final diagnosis is crucial to be immediately established.

Funding Acknowledgement

Type of funding sources: None.

Right heart response to different loading conditions - a comparison of chronic volume versus pressure overload using an integrated echocardiographic and invasive approach

Funding Acknowledgements

Type of funding sources: None.

Background. It is widely believed that right ventricular (RV) volume overload is better tolerated than RV pressure overload and this is mainly due to the preservation of or even an increase in RV longitudinal function in patients (pts) with RV volume overload. Conversely, patients with RV pressure overload experience an early decrease in radial shortening and the global RV performance is maintained due to a normal longitudinal function. The multiparametric assessment of RV function and RV-pulmonary artery (PA) coupling could offer a better understanding of the RV adaptive mechanisms in response to volume versus pressure overload.

Purpose. To assess the right heart remodelling and function in different chronic loading conditions using an integrated echocardiographic and invasive approach.

Methods. Thirty-nine patients with atrial septal defect (ASD) and 41 pts with pulmonary hypertension (PH) age and gender-matched were enrolled. The etiology of PH was idiopathic (14 pts), operated congenital heart disease (3), connective tissue disease (9), chronic thromboembolic PH (8) and other forms of arterial PH (7). Clinical parameters, B-type natriuretic peptide (BNP), RV function and pulmonary artery stiffness (PAS) echocardiographic parameters were assessed. RV-PA coupling was assessed using the TAPSE to systolic PA pressure ratio. A right heart catheterization was also performed and ASD pts with pulmonary vascular resistance >3 Wu and/or Qp/Qs ratio <1.5 were excluded.

Results. PH pts were more symptomatic than pts with ASD (32 PH pts vs 6 ASD pts were in NYHA class III and IV, p < 0.001). ASD pts had lower BNP levels (lnBNP 4.24 ± 1.11 vs 5.49 ± 1.29, p < 0.001), similar right atrial (RA) area (26.6 ± 7.7 vs 27.8 ± 11.9 cm2, p = 0.61) and pressure (7.5 ± 4.2 vs 8.2 ± 5.9 mmHg), lower systolic (1.11 ± 0.13 vs 1.55 ± 0.50) and diastolic (1.21 ± 0.16 vs 1.50 ± 0.32) eccentricity index (p < 0.001) and better RV function parameters than PH pts (all p < 0.001): TAPSE (26 ± 5 vs 16 ± 3 mm), RV-free wall S wave (14.4 ± 2.5 vs 9.9 ± 2.1 cm/s), RV fractional area change (46 ± 8 vs 32 ± 8%), RV global longitudinal strain on 3 segments (-27.6 ± 5.0 vs -14.4 ± 6.0%) or 6 segments (-24.2 ± 4.3 vs -12.5 ± 4.9%). Also, ASD pts had less impaired PAS parameters (pulmonary compliance 4.03 ± 5.54 vs 1.53 ± 3.01 mm2/mmHg, p = 0.016; elastic modulus 167 ± 131 vs 594 ± 369 mmHg, p < 0.001; beta index 5.36 ± 3.77 vs 11.00 ± 6.39, p < 0.001) and better RV-PA coupling (0.60 ± 0.20 vs 0.19 ± 0.06 mm/mmHg, p < 0.001) than PH pts. The BNP levels significantly correlated with RA area, parameters of RV size and systolic function and RV-PA coupling in both groups, but invasively assessed PA pressure correlated with BNP levels only in ASD pts.

Conclusions

Patients with ASD as a model of chronic RV volume overload have not only preserved RV longitudinal function but also better global RV function, PAS and RV-PA coupling compared to pts with chronic RV pressure overload. The BNP levels are significantly more impaired in pts with chronic RV pressure overload.

Mitochondria in Diabetic Kidney Disease

Diabetic kidney disease (DKD) is the leading cause of end stage renal disease (ESRD) in the USA. The pathogenesis of DKD is multifactorial and involves activation of multiple signaling pathways with merging outcomes including thickening of the basement membrane, podocyte loss, mesangial expansion, tubular atrophy, and interstitial inflammation and fibrosis. The glomerulo-tubular balance and tubule-glomerular feedback support an increased glomerular filtration and tubular reabsorption, with the latter relying heavily on ATP and increasing the energy demand. There is evidence that alterations in mitochondrial bioenergetics in kidney cells lead to these pathologic changes and contribute to the progression of DKD towards ESRD. This review will focus on the dialogue between alterations in bioenergetics in glomerular and tubular cells and its role in the development of DKD. Alterations in energy substrate selection, electron transport chain, ATP generation, oxidative stress, redox status, protein posttranslational modifications, mitochondrial dynamics, and quality control will be discussed. Understanding the role of bioenergetics in the progression of diabetic DKD may provide novel therapeutic approaches to delay its progression to ESRD.

Cardiac remodelling and heart failure symptoms in patients with apical hypertrophic cardiomyopathy

Funding Acknowledgements

Type of funding sources: None.

Background

Although earlier publications suggested a more benign clinical course for patients (pts) with apical hypertrophic cardiomyopathy (ApHCM), recent studies report increased morbidity and mortality, comparable to the prognosis of other HCM variants. Moreover, information regarding cardiac remodelling and its relationship with symptoms in pts with ApHCM is scarce. The aim of our study was to assess left ventricular (LV), right ventricular (RV) and left atrial (LA) remodelling in pts with ApHCM in comparison with non-apical variants of HCM (nonApHCM), and the impact of cardiac remodelling on heart failure symptoms.

Methods

One hundred fifty-one consecutive pts with HCM (52 ± 16 yrs, 47% men) in sinus rhythm and with preserved LV ejection fraction (16 pts with ApHCM and 135 pts with nonApHCM), were prospectively enrolled. Comprehensive echocardiography was performed in all, including the measurement of maximal LV wall thickness (LVWT), RV free wall thickness (RVWT) and maximal LA volume indexed to body surface area (LAVi). Global LV strain (ɛ), RVɛ, LAɛ and end-diastolic LA strain rate (ASr) were measured using speckle-tracking echocardiography (STE). The ratio of E to average e’ was used to estimate LV filling pressure. The degree of mitral regurgitation (1/2/3) has also been assessed. Heart failure symptoms were defined according to the New York Heart Association (NYHA) classification.

Results

Forty-eight pts in nonApHCM group had intraventricular obstruction. There were no significant differences between pts with and without ApHCM regarding: age (58 ± 20 vs 52 ± 16 yrs), gender distribution, RVWT, LVɛ (-14.9 ± 2.7 vs -13.9 ± 3.5 %), RVɛ (-19.6 ± 3.6 vs -10.0 ± 5.0%), LAɛ (19.2 ± 5.8 vs 16.4 ± 7.1%)(p > 0.05 for all). Pts with ApHCM had lower values for LVWT (17.2 ± 1.9 vs 21.4 ± 5.2 mm, p = 0.002), E/e’ (12.0 ± 5.8 vs 17.6 ± 8.5, p = 0.02) and LAVi (48 ± 16 vs 61 ± 25, p = 0.03) compared to pts with nonApHCM. Pts with ApHCM had slightly better LA contractile function as assessed by ASr (-1.23 ± 0.50 vs -0.97 ± 0.49 sec-1, p = 0.05). Mitral regurgitation was more often severe in nonApHCM pts (56/42/31 vs 10/4/0, p < 0.001). There was no significant difference between the percentage of symptomatic pts (NYHA class ≥2) in ApHCM vs nonApHCM group (p = 0.3). In the ApHCM group, symptomatic pts had significantly lower ASr compared to asymptomatic pts (-0.98 ± 0.35 vs -1.61 ± 0.46 sec-1, p = 0.01).

Conclusions

Despite of lower LVWT values, less severe MR and no obstruction, pts with apical HCM have similar prevalence of heart failure symptoms, and similar LV, RV and LA dysfunction compared to pts with non-apical HCM. Symptomatic pts with apical HCM have worse LA contractile function compared to asymptomatic pts.

Left atrial dysfunction in patients with prosthesis-patient mismatch after transcatheter aortic valve replacement

Funding Acknowledgements

Type of funding sources: None.

Background. Transcatheter aortic valve replacement (TAVR) prostheses have better hemodynamics compared to surgical prostheses, with lower incidence of prosthesis-patient mismatch (PPM). Nonetheless, this complication is neither rare nor benign in the expanding population of TAVR patients (pts). Data regarding the effect of TAVR PPM on cardiac function is scarce. Our aim was to determine the short-term impact of PPM on left atrium (LA) function in patients undergoing transfemoral TAVR.

Methods. One hundred forty-three consecutive pts (76.3 ± 7.5 yrs, 74 men) considered to be at high risk for SAVR were enrolled and examined before and 30 days after TAVR. All pts underwent a comprehensive echocardiogram, including speckle tracking echocardiography (STE) for LA and left ventricular (LV) strain analysis. Longitudinal LA strain parameters were assessed from the apical 4-chamber view. Peak values of global longitudinal LA strain (LAε) and LA systolic strain rate (SSr, reservoir function) and early diastolic strain rate (ESr, conduit function) were measured in all. Contractile LA function (late diastolic strain rate, ASr) was assessed in patients in sinus rhythm (106 pts).

Results. Fifty-five pts (38%) had PPM (defined as an indexed effective orifice area, EOA ≤0.85 cm2/m2). Most of these pts (71%) had moderate PPM (indexed EOA between 0.65 and 0.85 cm2/m2). No significant differences in age (76.4 ± 8.1 vs 76.3 ± 7.2 yrs, p = 0.9), gender (p = 0.2), body surface area (p = 0.8), body mass index (p = 0.2) and the presence of cardiovascular risk factors (p > 0.2 for all) were observed between pts with and without PPM. The severity of post-TAVR aortic regurgitation was mild in 92 pts (64%) and moderate in 12 pts (8%) without any significant difference between pts with and without PPM. The post-TAVR prevalence of ³moderate mitral regurgitation was not different between the two groups (p = 0.40). After TAVR, there were no significant differences in terms of indexed LV mass, volumes, ejection fraction (p > 0.5 for all). LV global longitudinal strain was also similar between groups (-13.7 ± 4.3 vs -14 ± 3.6%, p = 0.7). Although LA volumes were similar between patients with and without PPM (47.8 ± 12.4 vs 49.3 ± 20.3 ml/m2, p = 0.6), in the mismatch-group we found a significantly reduced systolic global LA strain (12.7 ± 6.2 vs 15.9 ± 7.9%, p = 0.009) and impaired LA contractile function (ASr: -1.0 ± 0.4 vs -1.2 ± 0.5, p = 0.03). Parameters of LV diastolic function were also worse in the mismatch-group, with an E/e’sep ratio of 22 ± 10 vs 17 ± 7, p = 0.01.

Conclusions. In our study group TAVR was associated with an incidence of PPM of 38%. The short-term follow-up of these patients revealed a significantly impaired LA function and increased LV filling pressure in patients with PPM compared to those without PPM. To our knowledge, this is the first report about the effect of PPM on the LA global and contractile function.

Right ventricle to pulmonary artery coupling improves early after transcatheter aortic valve implantation and this is related to improved left atrial function

Background

Transcatheter aortic valve implantation (TAVI) improves not only left heart remodeling but also has an upstream effect on the right ventricle and pulmonary vasculature. Right ventricle (RV) to pulmonary artery (PA) coupling, a parameter which integrates RV systolic performance at a given degree of afterload, was associated with all-cause mortality in these patients (pts). Our aim was to evaluate the short-term effect of TAVI on RV-PA coupling and the main determinants of RV-PA coupling in pts with aortic stenosis (AS) undergoing transfemoral TAVI.

Methods

We have prospectively enrolled 102 consecutive pts (76±8 years, 57 men) with severe AS undergoing TAVI. All pts underwent a comprehensive echocardiogram both before and 30 days after TAVI, including speckle tracking echocardiography (STE) for myocardial deformation analysis. Peak values of global longitudinal left ventricular strain (GLS), left atrial strain (LAε, reservoir function), and late diastolic LA strain rate (ASr, contractile function) were measured. The ratio of tricuspid annular plane systolic excursion (TAPSE) to PA systolic pressure (PASP) was used as an estimate of RV-PA coupling.

Results

Compared with baseline, there was a significant increase in LV ejection fraction after TAVI (54±12% vs 50±13%, p=0.04), a significant reduction in LV mass (147±35 vs 171±44 g/m2, p<0.001) and increase in absolute GLS values (14±3% vs 12±5%, p=0.007). Indexed LA volumes decreased (49±19 vs 55±19 ml/m2, p=0.03) while both global LAε and ASr improved significantly after TAVI (16±8% vs 13±7%, p=0.01 and −1.2±0.6 vs −0.9±0.6%, p=0.01). A significant improvement of TAPSE/PASP values (0.069±0.026 vs 0.057±0.025 cm/mm Hg, p<0.001) was found after TAVI, indicating an enhanced RV-PA coupling. In multivariable regression analysis global LAε was independently related to RV-PA coupling, both before and after TAVI (R=0.54, p=0.003 and R= 0.39, p<0.001). The increase in RV-PA coupling was significantly related to the increase in LAε (p=0.005).

Conclusions

Our results confirm that relief of aortic valve obstruction by TAVI has beneficial effects on the RV-PA coupling, that occur early after intervention. This is accompanied by a significant improvement in LV and LA deformation. Moreover, there is a significant correlation between LA function and RV-PA coupling both before and after TAVI. Enhanced RV-PA coupling after TAVI is related to improved LA strain, suggesting the contribution of LA function in modulating right heart function in this setting.

Funding Acknowledgement

Type of funding source: None

P301 The prognostic value of preoperative left atrial volume after surgical aortic valve replacement in patients with isolated severe aortic stenosis and preserved left ventricular ejection fraction

Background

Left atrial (LA) volume is an important cardiovascular prognostic marker. However, data regarding the prognostic value of LA volume in severe AS patients (pts) after surgical aortic valve replacement (AVR) are scarce. Moreover, the predictive role of LA function in AS pts after AVR has not yet been studied. Our study aimed to assess the relationship of LA volume index (LAVi) and function with outcome, in terms of mortality, in severe AS pts who underwent surgical AVR.

Methods

A total of 360 consecutive pts with isolated severe AS (aortic valve area index ≤ 0.6 cm2/m2) referred to our echocardiography laboratory were prospectively screened. Two hundred and seventeen pts with preserved left ventricular (LV) ejection fraction (≥50%) and in sinus rhythm were enrolled. All patients underwent a baseline comprehensive echocardiogram, including speckle tracking analysis of both LV and LA strain. Symptomatic pts (142 pts, 65%) that were subject to AVR were followed for a median period of 4 years (IQR 3-6 years). The endpoint was all-cause mortality after AVR. The last update of the survival status was obtained in January 2019. Outcome data were available in 116 severe AS pts that underwent AVR (mean age 63 ± 10 yrs, 56% men), who formed the final study population.

Results

Seventeen (14%) pts died during follow-up. No significant differences were found between nonsurvivors and survivors after AVR in terms of age and cardiovascular risk factors. Nonsurvivors had higher BNP plasma values (p=.04) at baseline compared with surviving pts. Survivors and nonsurvivors alike exhibited similar preoperative AS severity and LV systolic function parameters (ejection fraction and global longitudinal strain). Moreover, there were no significant differences between the two groups regarding baseline valvuloarterial impedance, average E/e’ ratio, and LA longitudinal deformation parameters. Nonsurvivors had a tendency toward higher LV mass index (p=.08). Nonsurvivors had higher preoperative LA volume index (LAVi)(50 ± 12 vs. 44 ± 10 ml/m2, p=.003). In a multivariable Cox regression analysis adjusted for age, LAVi emerged as the only independent predictor for death in our population study (HR 1.06, 95% CI 1.01-1.11, p=.02). A cut-off value for LAVi derived from ROC curve analysis was used to construct Kaplan-Meier survival curves. A value of 43 ml/m2 for LAVi predicted all-cause mortality after AVR in severe AS pts with 71% sensitivity and 54% specificity.

Conclusions

In our study, preoperative LAVi predicted death in severe AS pts after surgical AVR. LAVi assessment may improve preoperative risk stratification in patients with severe AS, however further larger prospective studies are needed.

Abstract P301 Figure.

621 Anemia and its impact on clinical, echocardiographic parameters and prognosis in patients with severe aortic stenosis and normal left ventricular ejection fraction

Background

Anemia is common in patients (pts) with severe aortic stenosis (AS). Untreated anemia and severe AS are individually associated with the development of heart failure, however data regarding the potential detrimental effect of anemia on left ventricular (LV) function and prognosis in pts with severe AS are controversial.

Aim

To investigate the impact of anemia on clinical status, echocardiographic parameters and prognosis in pts with severe AS and preserved LV ejection fraction (LVEF).

Methods

Consecutive patients with severe AS (aortic valve area [AVA] index ≤ 0.6 cm2/m2) and preserved LVEF (>50%) referred to our echocardiography laboratory were prospectively screened. All patients underwent complete clinical examination and comprehensive echocardiography, including speckle tracking-derived measurements of LV and left atrial (LA) strain. Baseline clinical variables included NYHA class, cardiac risk factors, haemoglobin (Hb) level and glomerular filtration rates (GFR, by MDRD formula). The definition of anemia was based on gender-specific cut-off values, as recommended by the WHO (Hb <13.0 g/dL for men, <12.0 g/dL for women). Patients with more than mild aortic regurgitation or mitral valve disease, atrial fibrillation or cardiac pacemakers were excluded.

Results

The study population included 264 patients (pts) (66 ± 11 yrs, 147 men). Anemia was present in 64 pts (24%). Aortic valve replacement (AVR) was performed in 151 pts. Dividing the study population into 2 groups, according to the presence/absence of anemia, no significant differences were found between groups regarding: age (p = 0.09), body surface area (p = 0.6), LVEF (62 ± 7 vs 63 ± 6%, p = 0.2), LV Global Longitudinal Strain (-15.2 ± 4 vs -14.7 ± 3 %, p = 0.4), LV mass index (p = 0.9), mean aortic gradient (p = 0.2) and indexed AVA (0.40 ± 0.09 vs 0.39 ± 0.09 cm2/m2, p = 0.6), or presence of significant coronary artery disease (p = 0.9). Compared to pts with normal Hb level, in pts with anemia NYHA class (p = 0.03), brain natriuretic peptide values (p = 0.004), lateral E/e’(16.2 ± 6.9 vs 13.7 ± 6.3, p = 0.01) and average E/e" ratio (15.9 ± 5.9 vs 14.1 ± 5.3, p = 0.03), LA volume index (54.3 ± 16.9 vs 45.0 ± 12.1 ml/m2, p < 0.001), and systolic pulmonary artery pressure (38 ± 13 vs 33 ± 8, p = 0.009) were all significantly higher. During a 3–years follow-up 47 pts died. Age, NYHA class, BNP serum level, baseline anemia, LA volume index and systolic pulmonary pressure were associated with all-cause mortality in the whole study group (p < 0.03 for all). In the group of pts who underwent AVR, NYHA class was the only independent predictor of all-cause mortality.

Conclusions

In our study including pts with severe AS and preserved LVEF, patients with baseline anemia presented worse functional status and LV diastolic dysfunction and increased 3-year all-cause mortality compared to those with normal Hb levels. However, in pts who underwent surgical AVR, there was no impact of baseline anemia on 3-year survival.

P827 Left atrial contractile function is the main correlate of atrial fibrillation in patients with hypertrophic cardiomyopathy

Background

Given the negative impact of atrial fibrillation (AF) in patients (pts) with hypertrophic cardiomyopathy (HCM), finding new and better predictors of AF is clinically important, especially for patients considered at low or intermediate risk based on current recommendations (i.e. left atrial diameter, LAD <45 mm).

Purpose

To assess the relationship between left atrial (LA) remodelling (size and function) and the presence of paroxysmal AF in HCM patients with and without increased LAD.

Methods

A comprehensive echocardiogram was performed in 110 consecutive pts (52 ± 17 years, 50 men) with HCM, in sinus rhythm. Indexed LA volume (LAVi), maximum left ventricular wall thickness (LVWT), LV ejection fraction, E/e’ ratio were determined. Global longitudinal LV strain (GLS) and LA strain parameters (LAɛ, SSr, ASr) were assessed by speckle tracking echocardiography. Patients were divided into two groups according to the presence (30 pts) or absence (80 pts) of documented paroxysmal AF (24/48 h ambulatory ECG recordings)

Results

Patients with AF were older than pts without AF (p < 0.001). LAD, LAVi, E/e’ were significantly higher, while LAɛ, ESr, ASr were significantly lower in pts with AF compared to pts without AF (p < 0.05 for all). There were no significant differences between pts with and without AF regarding: gender, LVWT, GLS, the presence and severity of LV outflow tract obstruction (p > 0.05 for all). The correlates of AF in the whole HCM study population were: age (OR = 1.05, p = 0.001), ASr (OR = 10.1, p < 0.001), LAVi (OR = 1.03, p = 0.004), LAD (OR = 1.2, p = 0.001), E/e’(OR = 1.05, p = 0.02) and mitral regurgitation degree (OR = 1.6, p = 0.04). ASr had the best area under the curve (AUC: 0.74) with a cutoff of -0.88 s-1 for identifying HCM patients with AF (sensitivity: 80%, specificity: 65%). At multivariable logistic regression analysis, age, LAVi and ASr emerged as the only independent correlates of AF. 14 of the 71 patients with a LAD < 45 mm had paroxysmal AF. In this selected population, pts with AF were older (p = 0.001), had higher values for E/e’ (p = 0.04) and lower values for ASr (p = 0.02) than pts without AF. Moreover, in this subgroup of pts, at multivariable logistic regression analysis, ASr correlated with AF independently of age, LA dimensions, LV hypertrophy or E/e’ (OR = 10.008, 95% CI 1.297-77.219, p = 0.02).

Conclusions

In pts with HCM, age, LAVi and ASr, were independently related to the presence of AF, while LAD was not. Moreover, in the subgroup of HCM pts with LAD < 45 mm, ASr (reflecting LA contractile function) was the only LA remodelling parameter correlated with the presence of AF. The assessment of LA volume and function can provide further insights into the risk stratification of pts with HCM, especially in pts considered at lower risk for AF based on the assessment of classical risk parameters, such as LAD.

P216 Cardiac amyloidosis is not a single disease: an echocardiographic study of light chain vs transthyretin forms

Background

Cardiac amyloidosis (CA) is described as one entity. However, several subtypes of amyloid can infiltrate the heart: light chain (AL) and tranthyretin (ATTR) are the most common.

Purpose

To characterize the specific findings of the CA subtypes as a tool to aid differential diagnosis between AL and ATTR CA.

Material and methods: Consecutive patients with CA were evaluated by clinical examination, ECG, cardiac biomarkers and echocardiography with both conventional and myocardial deformation study of the left ventricle (LV), left atrium (LA) and right ventricle (RV). Amyloid subtype was described using light chain assessment for AL-CA and 99Tc-HMPD scintigraphy and TTR gene sequencing for ATTR-CA.

Results

32 patients with CA were included, 13 with ATTR and 19 with AL. Patients in AL group were significantly older, with higher levels of cardiac biomarkers. At similar LV EF and wall thickness, they had lower GLS. LA function parameters were also lower in AL pts (table). Using ROC curves, the best predictors for AL diagnosis were NTproBNP (AUC 0.937) and Tn levels (AUC 0.958), as well as LV GLS and pericardial fluid presence (both AUC 0.750).

Conclusions

At similar LV wall thickness and ejection fraction, cardiac dysfunction appears to be more severe in AL pts, with lower global LV longitudinal strain, worse LA function, higher sPAP and NTproBNP.

ATTR (13 pts) AL (19 pts) p Age (years) 50 ± 12 60 ± 8 0.01 NTproBNP (pg/mL) 3066 ± 3720 11755 ± 9114 0.02 hsTnI (ng/mL) 0.005 ± 0.008 0.147 ± 0.161 0.04 Pericardial fluid (%) 53% 100% 0.002 LVEDV (mL) 88 ± 25 75 ± 38 NS LVMi (g/m2) 166 ± 47 168 ± 41 NS LVEF (%) 50 ± 8 49 ± 16 NS LV GLS (%) -12.1 ± 3.8 -8.9 ± 4.5 0.04 Septal Basal/Apical LS 0.33 ± 0.17 0.25 ± 0.27 NS LAVi (mL/m2) 46 ± 21 45 ± 14 NS LAEF 4CV (%) 35 ± 21 24 ± 8 0.05 LA systolic strain (%) 17.4 ± 11.9 10.5 ± 5.0 0.02 RV free wall thickness (mm) 7.0 ± 1.5 7.6 ± 1.4 NS RV 6-segments strain (%) -15 ± 4 -10 ± 8 0.09 sPAP (mmHg) 36.6 ± 12.0 48.6 ± 17.2 0.04

1100 When multimodality imaging is needed to understand the etiology of diffuse negative t waves

Introduction

We present the case of a 50 year old woman, active smoker, hypercholesterolemic, nondiabetic, with normal body mass index, referred to our cardiology department for atypical chest pain and ECG changes (diffuse negative T waves in V1-V6, DII, DIII) (Panel A), also present on a resting ECG recorded 4 years previously.

Purpose

To highlight the fact that even though the most frequent cause of negative T waves remains coronary artery disease (CAD), the cause could be related to other more rare medical conditions.

Methods

After clinical examination and ECG, 2D echocardiography was performed. It revealed a normal sized left ventricle (LV) with perserved global and regional function, normal global longitudinal strain, nondilated atria and no significant valvular disease. The subcostal view suggested a hypertrophied right ventricle (RV) free wall (10 mm thickness, with apparent homogeneous echogenicity) (Panel B, arrow), with normal longitudinal function and no regional wall motion abnormalities.

Cardiac magnetic resonance (CMR) was performed for a better tissue characterization. The CMR examination found normal cardiac cavities, normal wall thickness of both ventricles (RV free wall of 3 mm), no late gadolinium enhancement, but described a large amount of fat with concentric disposition, maximum thickness of 9 mm anterior of RV, 3 mm posterior of LV (Panel C).

Since this was not fully explaining the ECG changes and the patient presented with a low-intermediate pretest probability for CAD, an angio-CT coronary scan was performed and showed a calcium score of 7 AU, no significant coronary atherosclerosis, and a hypoplastic circumflex artery (Panel D, arrow). A total volume of 149 ml. of pericardial fat was measured (Panel E).

Stress echocardiography was performed with maximal workload achieved (145 bpm, 85% predicted, 100 W); no chest pain was reported, no regional wall motion abnormalities were seen and there was normal contractile reserve.

Results

Using multimodality imaging a differential diagnosis was followed, which included: arrhythmogenic cardiomyopathy (negative T waves, apparent changes of RV free wall on echo, but no family history of sudden cardiac death), CAD (atypical angina, cardiovascular risk factors, negative T waves), and pericarditis (but negative inflammatory markers, no pericardial fluid). The final hypothesis is that the ECG changes are related to the abnormal pericardial adipose tissue deposit, which acts similar to pericarditis.

Conclusions

The present case report is, to our knowledge, the first to describe an association between large pericardial fat deposit and ECG changes, when other causes were excluded. Even if the current findings are benign, the patient should be followed closely, and risk factors should be thoroughly controlled, as several studies have shown that pericardial fat is associated with poorer cardiovascular prognosis

Abstract 1100 Figure. Multimodality imaging in our patient

P757 Left atrial contractile function improves shortly after transcatheter aortic valve replacement. A speckle tracking echocardiography study

Background

Transcatheter aortic valve replacement (TAVR) reverses LV remodeling and improves overall cardiac function, but data regarding its effect on left atrial (LA) function is scarce. Our aim was to evaluate the short-term effect of TAVR on LA myocardial deformation parameters and the relationship between the improvement of LA function and baseline echocardiographic parameters.

Methods

Fourty-eight consecutive pts (75 ± 6 yrs, 28 men) considered to be at increased risk for surgical aortic valve replacement were enrolled and examined before and 30 days after TAVR. All pts underwent a comprehensive echocardiogram, including speckle tracking echocardiography (STE) for deformation analysis. Longitudinal LA strain parameters were assessed from the apical 4-chamber view. Peak values of global longitudinal LA strain (LAε) and LA systolic strain rate (SSr, reservoir function) and early diastolic strain rate (ESr, conduit function) were measured in all. Contractile LA function (late diastolic strain rate, ASr) was assessed in patients in sinus rhythm (39 pts).

Results

Compared with baseline, the mean indexed LV mass was significantly reduced after TAVR (141 ± 26 vs 160 ± 37 g/m2, p = 0.009) but the mean increase in LVEF was not statistically significant (51 ± 14% vs 47 ± 15%, p = 0.2). There was a significant reduction in systolic pulmonary pressure after TAVR (34 ± 12 vs 42 ± 13, p = 0.004). Although there was no significant decrease in indexed LA volume (51 ± 22 vs 56 ± 20 ml/m2, p = 0.3), the contractile LA function significantly improved 30-days after TAVR (mean ASr, -1.1 ± 0.5 vs -0.8 ± 0.4 %, p = 0.02). There was a tendency of improvement in global longitudinal LA strain (15 ± 7 vs 12 ± 6%, p = 0.06) and global longitudinal LV strain (-13 ± 4 vs -11 ± 5%, p = 0.06) as well. Parameters of LV diastolic function, including TDI derived e’ and E/e’ ratios were not significantly improved 30 days after TAVI. While LA volumes and function parameters were not significantly different between genders at baseline, the improvement of LA function was more frequently found in male pts (p = 0.05). There were no significant correlations between the improvement of LA function parameters and baseline echocardiographic parameters in our study group. The only predictor of LA booster function improvement was the baseline value of ASr (p = 0.01).

Conclusions

TAVR is associated with a significant recovery of LA function as assessed by STE, suggesting a reverse cavity remodeling. This was accompanied by a significant reduction in LV mass and systolic pulmonary pressure. Men seem to show a more significant improvement in LA contractile function, suggesting a gender-related LA response to chronic afterload reduction.

P1545 Predictors of survival in patients with pulmonary hypertension receiving specific vasodilator therapy

In patients with pulmonary hypertension (PH) right ventricular (RV) function is a well-recognized determinant of clinical outcome, including cardiac death. Data regarding the prognostic value of comorbidities in patients with PH are scarce. Purpose. To identify predictors of cardiac death and all-cause mortality on mid-term follow-up in PH patients receiving specific vasodilator therapy. Methods. Sixty-eight patients (40 ± 16 years, 51 women) with PH (12 with idiopathic pulmonary arterial hypertension-PAH, 32 with congenital heart disease, 10 ith connective tissue disease, 7 with chronic thromboembolic PH and 7 with other forms of PAH) treated with pulmonary vasodilators were studied. Clinical parameters (NYHA class, 6-minutes walking distance, 6MWD), biological (hemoglobin, B-type natriuretic peptide-BNP), and echocardiographic parameters of RV function (TAPSE, tissue-Doppler imaging-derived free-RV wall S- and e’-wave, RV fractional area change (FAC), Tei index, I/H, RV isovolumic acceleration-IVA) and cardiac index were assessed. RV global longitudinal strain (RV-GLS) was measured from the apical 4-chamber view as the average of 3 (free-wall) and 6 (free-wall and interventricular septum) segments by 2D speckle-tracking echocardiography. Parameters of pulmonary artery stiffness (PAS) were assessed: pulsatility, capacitance, elastic modulus, dynamic compliance. Two endpoints were defined: cardiac death and all-cause mortality. Results. PH patients were followed-up for 35 months (4-81). Comorbidities were identified in 15 patients (non-cardiac surgery, anemia, chronic kidney disease, neoplasia, respiratory infections). During follow-up, 20 patients died, 14 deaths being cardiac deaths. At univariable analysis, the following parameters correlated with all-cause mortality: age (51 ± 14 in deceased patients vs 36 ± 15 years in surviving patients, p < 0.001), 6MWD (262 ± 171 vs 369 ± 155 m, p = 0.015), FAC (30 ± 9 vs 38 ± 8%, p < 0.001), 6 segments RV-GLS (-12.3 ± 5.1 vs -15.1 ± 4.5%, p = 0.025), S-RV (9.9 ± 2.2 vs 11.4 ±2.3 cm/s, p = 0.016), TAPSE (16.3 ± 3.3 vs 18.6 ± 3.5 mm, p = 0.014), right atrial (RA) area (30.6 ± 13.1 vs 21.2 ± 8.8 cm2, p = 0.001) hemoglobin (12.9 ± 2.6 vs 15.2 ± 3.0 g/dl, p = 0.004) and BNP levels (lnBNP, 5.8 ± 1.3 vs 4.1 ± 1.4, p < 0.001), presence of comorbidities (10 vs 5, p = 0.001). At multivariable analysis, only comorbidities (p = 0.05) and FAC (p = 0.07) seemed to independently predict all-cause mortality. Predictors of cardiac death at univariate analysis were age, RV function parameters, RA area, PA capacitance (1.02 ± 0.56 vs 1.48 ± 0.80 ml/mmHg, p = 0.05) and cardiac index (2.48 ± 0.64 vs 3.31 ± 1.34 l/min/m2, p = 0.03) but only age (p = 0.03) and cardiac index (0.06) emerged as independent predictors of cardiac death. Conclusions: In PH patients, RV function and comorbidities predict all-cause mortality, while age and cardiac index are independent determinants of cardiac death. Identifying and properly treating associated pathologies could impact survival in this setting.

P888Left ventricular diastolic function and left atrial longitudinal function during exercise correlate with exercise capacity in patients with hypertrophic cardiomyopathy

Background

The clinical course of hypertrophic cardiomyopathy (HCM) is heterogeneous and the development of heart failure (HF) is difficult to predict. Exercise echocardiography can provide information about mechanisms involved in the occurrence of HF symptoms: development of intraventricular obstruction, increase in mitral regurgitation (MR) severity, impaired left ventricular (LV) and left atrial (LA) function.

Purpose

To analyse the changes in LV and LA function during exercise and to identify the main correlates of exercise capacity in patients (pts) with HCM, in sinus rhythm and with normal LV ejection fraction.

Methods

We have prospectively enrolled 32 pts (48±17 years, 15 men) with HCM and no obstruction at rest. A symptom limited exercise echocardiogram was performed in all pts using a table ergometer. Maximum LV wall thickness (LVWT), indexed left atrial volume (LAVi), septal E', E/septal E' ratio, were measured at rest (r) and during exercise (e). Global longitudinal LV strain (GLS) and LA strain (LAɛ) were assessed by speckle tracking echocardiography at rest and during exercise. The peak LV outflow tract gradient, systolic pulmonary artery pressure (PAP), and MR degree were recorded at rest and during exercise. Exercise-related symptoms, peak exercise heart rate (HR) and exercise capacity calculated in metabolic equivalents (METs) were also recorded.

Results

The mean value of achieved METs was 5.9±1.4, the peak HR was 124±25 bpm, representing 72±12% of maximal HR, during a mean of 8.5±2.5 minutes of exercise. Thirteen pts developed LV gradients >30 mmHg. Fifteen pts were asymptomatic, while 17 pts reported dyspnea during exercise. There were no significant differences between pts with and without symptoms regarding: age, rE', rE/E', rGLS, rLAɛ, rMR, rPAP, LAVi, eE/e', eGLS, eMR, ePAP (p>0.05 for all). Symptomatic pts had lower values for eE' (p=0.01), eLAɛ (p=0.03) and tended to have higher values for LVWT (p=0.06) and a higher prevalence of eLV outflow tract obstruction (p=0.13) compared to asymptomatic pts. In symptomatic group of pts, E' (p=0.004), PAP (p<0.001) and GLS (p=0.04) significantly increased and LAɛ tended to decrease (p=0.18) during exercise. Age (r=−0.44, p=0.01), rE' (r=0.40, p=0.02), eE' (r=0.46, p=0.01), ePAP (r=−0.35, p=0.04) and LVWT (r=−0.32, p=0.07) significantly correlated with achieved METs in HCM pts overall. In multivariate analysis, eE' (β=0.60, 95% CI 0.122 to 0.009, p=0.003) was the only parameter independently correlated with exercise capacity (expressed in METs).

Conclusions

Symptomatic pts had a worse LV diastolic function (as expressed by E') and a severe LA longitudinal dysfunction (as expressed by LAɛ) during exercise. E' during exercise was the only parameter independently correlated with exercise capacity in pts with HCM. These suggest that a detailed analysis of LV and LA function during exercise could provide additional information to predict the occurrence of HF in HCM pts.

Assessment of Mitochondrial Respiration in Human Platelets

It has been long recognized that the impairment of platelet mitochondrial function occurs in a broad spectrum of diseases. Accordingly, the assessment of platelet respiratory dys/function has emerged as a putative approach allowing the characterization of the early impairment of human bioenergetic profile in several chronic pathologies. The aim of this study was to standardize the methodology for platelet isolation from peripheral blood and the measurement of mitochondrial oxygen consumption by means of high-resolution respirometry, respectively. The platelet isolation protocol consisted of two consecutive centrifugations of the whole blood collected from adult healthy females (n = 10) yielding a platelet-rich plasma sample. Respiration was measured at 370C using the Oxygraph-2k (Oroboros Instruments, Austria) according to a classic substrate-uncoupler-inhibitor-titration protocol. Platelets permeabilized with digitonin were allowed to respire in the presence of complex I (glutamate and malate) and complex II (succinate) substrates. We obtained a respiratory control ratio of 2.77 � 3.65 that indicates an accurate coupling efficiency of oxidative phosphorylation. The in vitro measurement of platelet respiration is a reliable method to evaluate the bioenergetic profile in humans. The standardized technique will be further used to assess the occurrence of mitochondrial dysfunction in peripheral blood in the setting of various chronic non-communicable diseases.

Gclc deficiency in mouse CNS causes mitochondrial damage and neurodegeneration

Gamma glutamyl cysteine ligase (GCL) is the rate-limiting enzyme for intracellular glutathione (GSH) synthesis. The GSH concentration and GCL activity are declining with age in the central nervous system (CNS), and is accompanied by elevated reactive oxygen species (ROS). To study the biological effects of low GSH levels, we disrupted its synthesis both at birth by breeding a Gclc loxP mouse with a thy1-cre mouse (NEGSKO mouse) and at a later age by breeding with a CaMKII-ERT2-Cre (FIGSKO mouse). NEGSKO mice with deficiency of the Gclc in their entire CNS neuronal cells develop at 4 weeks: progressive motor neuron loss, gait problems, muscle denervation and atrophy, paralysis, and have diminished life expectancy. The observed neurodegeneration in Gclc deficiency is of more chronic rather than acute nature as demonstrated by Gclc targeted single-neuron labeling from the inducible Cre-mediated knockout (SLICK) mice. FIGSKO mice with inducible Gclc deficiency in the forebrain at 23 weeks after tamoxifen induction demonstrate profound brain atrophy, elevated astrogliosis and neurodegeneration, particularly in the hippocampus region. FIGSKO mice also develop cognitive abnormalities, i.e. learning impairment and nesting behaviors based on passive avoidance, T-Maze, and nesting behavior tests. Mechanistic studies show that impaired mitochondrial glutathione homeostasis and subsequent mitochondrial dysfunction are responsible for neuronal cell loss. This was confirmed by mitochondrial electron transporter chain activity analysis and transmission electron microscopy that demonstrate remarkable impairment of state 3 respiratory activity, impaired complex IV function, and mitochondrial swollen morphology in the hippocampus and cerebral cortex. These mouse genetic tools of oxidative stress open new insights into potential pharmacological control of apoptotic signaling pathways triggered by mitochondrial dysfunction.

Multiple muscle cell alterations in a case of encephalomyopathy

Skeletal muscle from an encephalomyopathy was examined by morphological and biochemical modalities. Mitochondria displayed variability in size, numbers per myocyte, and morphology. Certain organelles had stacks of dense cristae, others contained variable numbers of crystalloids or several lipid droplets. In isolated skeletal muscle mitochondria, oxidative phosphorylation was reduced, but activities of the electron transport chain components were unaffected. This is the second case of adult onset encephalomyopathy with a phenotype overlapping MERRF and Kearns-Sayre syndrome associated with a heteroplasmic mtDNA 3255G > A mutation in the tRNA(UUR(LEU)). This study emphasizes the desirability of a multidisciplinary approach in the diagnosis of complex myopathies.