Characterization and natural history of different phenotypes in hereditary transthyretin amyloidosis: 40-year experience at a single Italian referral centre

AIMS

Hereditary transthyretin amyloidosis (ATTRv) is one of the leading aetiologies of systemic amyloidosis with more than 135 mutations described and a broad spectrum of clinical manifestations. We aimed to provide a systematic description of a population of individuals carrying pathogenic mutations of transthyretin (TTR) gene and to investigate the major clinical events during follow-up.

METHODS AND RESULTS

This was an observational, retrospective, cohort study including consecutive patients with mutations of TTR gene, admitted to a tertiary referral centre in Bologna, Italy, between 1984 and 2022. Three hundred twenty-five patients were included: 106 asymptomatic carriers, 49 cardiac phenotype, 49 neurological phenotype, and 121 mixed phenotype. Twenty-two different mutations were found, with Ile68Leu (41.8%), Val30Met (19%), and Glu89Gln (10%) being the most common. After a median follow-up of 51 months, 111 patients (38.3%) died and 9 (11.5%) of the 78 asymptomatic carriers developed ATTRv. Carriers had a prognosis comparable with healthy population, while no significant differences were seen among the three phenotypes adjusted by age. Age at diagnosis, New York Heart Association class III, left ventricular ejection fraction, modified polyneuropathy disability score IV, and disease-modifying therapy were independently associated with survival.

CONCLUSION

This study offers a wide and comprehensive overview of ATTRv from the point of view of a tertiary referral centre in Italy. Three main phenotypes can be identified (cardiac, neurological, and mixed) with specific clinical and instrumental features. Family screening programmes are essential to identify paucisymptomatic affected patients or unaffected carriers of the mutation, to be followed through the years. Lastly, disease-modifying therapy represents an evolving cornerstone of the management of ATTRv, with a great impact on mortality.

Clinical and Prognostic Implications of Right Ventricular Uptake on Bone Scintigraphy in Transthyretin Amyloid Cardiomyopathy

BACKGROUND

The extent of myocardial bone tracer uptake with technetium pyrophosphate, hydroxymethylene diphosphonate, and 3,3-diphosphono-1,2-propanodicarboxylate in transthyretin amyloid cardiomyopathy (ATTR-CM) might reflect cardiac amyloid burden and be associated with outcome.

METHODS

Consecutive patients with ATTR-CM who underwent diagnostic bone tracer scintigraphy with acquisition of whole-body planar and cardiac single-photon emission computed tomography (SPECT) images from the National Amyloidosis Centre and 4 Italian centers were included. Cardiac uptake was defined according to the Perugini classification: 0=absent cardiac uptake; 1=mild uptake less than bone; 2=moderate uptake equal to bone; and 3=high uptake greater than bone. Extent of right ventricular (RV) uptake was defined as focal (basal segment of the RV free wall only) or diffuse (extending beyond basal segment) on the basis of SPECT imaging. The primary outcome was all-cause mortality.

RESULTS

Among 1422 patients with ATTR-CM, RV uptake accompanying left ventricular uptake was identified by SPECT imaging in 100% of cases at diagnosis. Median follow-up in the whole cohort was 34 months (interquartile range, 21 to 50 months), and 494 patients died. By Kaplan-Meier analysis, diffuse RV uptake on SPECT imaging (n=936) was associated with higher all-cause mortality compared with focal (n=486) RV uptake (77.9% versus 22.1%; P<0.001), whereas Perugini grade was not associated with survival (P=0.27 in grade 2 versus grade 3). On multivariable analysis, after adjustment for age at diagnosis (hazard ratio [HR], 1.03 [95% CI, 1.02-1.04]; P<0.001), presence of the p.(V142I) TTR variant (HR, 1.42 [95% CI, 1.20-1.81]; P=0.004), National Amyloidosis Centre stage (each category, P<0.001), stroke volume index (HR, 0.99 [95% CI, 0.97-0.99]; P=0.043), E/e' (HR, 1.02 [95% CI, 1.007-1.03]; P=0.004), right atrial area index (HR, 1.05 [95% CI, 1.02-1.08]; P=0.001), and left ventricular global longitudinal strain (HR, 1.06 [95% CI, 1.03-1.09]; P<0.001), diffuse RV uptake on SPECT imaging (HR, 1.60 [95% CI, 1.26-2.04]; P<0.001) remained an independent predictor of all-cause mortality. The prognostic value of diffuse RV uptake was maintained across each National Amyloidosis Centre stage and in both wild-type and hereditary ATTR-CM (P<0.001 and P=0.02, respectively).

CONCLUSIONS

Diffuse RV uptake of bone tracer on SPECT imaging is associated with poor outcomes in patients with ATTR-CM and is an independent prognostic marker at diagnosis.

Real-world candidacy to mavacamten in a contemporary hypertrophic obstructive cardiomyopathy population

AIMS

In the EXPLORER-HCM trial, mavacamten reduced left ventricular outflow tract obstruction (LVOTO) and improved functional capacity of symptomatic hypertrophic obstructive cardiomyopathy (HOCM) patients. We sought to define the potential use of mavacamten by comparing real-world HOCM patients with those enrolled in EXPLORER-HCM and assessing their eligibility to treatment.

METHODS AND RESULTS

We collected information on HOCM patients followed up at 25 Italian HCM outpatient clinics and with significant LVOTO (i.e. gradient ≥30 mmHg at rest or ≥50 mmHg after Valsalva manoeuvre or exercise) despite pharmacological or non-pharmacological therapy. Pharmacological or non-pharmacological therapy resolved LVOTO in 1044 (61.2%) of the 1706 HOCM patients under active follow-up, whereas 662 patients (38.8%) had persistent LVOTO. Compared to the EXPLORER-HCM trial population, these real-world HOCM patients were older (62.1 ± 14.3 vs. 58.5 ± 12.2 years, p = 0.02), had a lower body mass index (26.8 ± 5.3 vs. 29.7 ± 4.9 kg/m2 , p < 0.0001) and a more frequent history of atrial fibrillation (21.5% vs. 9.8%, p = 0.027). At echocardiography, they had lower left ventricular ejection fraction (LVEF, 66 ± 7% vs. 74 ± 6%, p < 0.0001), higher left ventricular outflow tract gradients at rest (60 ± 27 vs. 52 ± 29 mmHg, p = 0.003), and larger left atrial volume index (49 ± 16 vs. 40 ± 12 ml/m2 , p < 0.0001). Overall, 324 (48.9%) would have been eligible for enrolment in the EXPLORER-HCM trial and 339 (51.2%) for treatment with mavacamten according to European guidelines.

CONCLUSIONS

Real-world HOCM patients differ from the EXPLORER-HCM population for their older age, lower LVEF and larger atrial volume, potentially reflecting a more advanced stage of the disease. About half of real-world HOCM patients were found eligible to mavacamten.

Predictors and outcomes of pacemaker implantation in patients with cardiac amyloidosis

OBJECTIVE

We sought to investigate prevalence, incidence and prognostic implications of permanent pacemaker (PPM) implantation in patients with cardiac amyloidosis (CA), thereby identifying the predictors of time to PPM implantation.

METHODS

Seven hundred eighty-seven patients with CA (602 men, median age 74 years, 571 transthyretin amyloidosis (ATTR), 216 light-chain amyloidosis (AL)) evaluated at two European referral centres were retrospectively included. Clinical, laboratory and instrumental data were analysed. The associations between PPM implantation and mortality, heart failure (HF) or a composite endpoint of mortality, cardiac transplantation and HF were analysed.

RESULTS

81 (10.3%) patients had a PPM before initial evaluation. Over a median follow-up time of 21.7 months (IQR 9.6-45.2), 81 (10.3%) additional patients (18 with AL (22.2%) and 63 with ATTR (77.8%)) underwent PPM implantation with a median time to implantation of 15.6 months (IQR 4.2-40), complete atrioventricular block was the most common indication (49.4%). Independent predictors of PPM implantation were QRS duration (HR 1.03, 95% CI 1.02 to 1.03, p<0.001) and interventricular septum (IVS) thickness (HR 1.1, 95% CI 1.03 to 1.17, p=0.003). The model to estimate the probability of PPM at 12 months and containing both factors showed a C-statistic of 0.71 and a calibration of slope of 0.98.

CONCLUSIONS

Conduction system disease requiring PPM is a common complication in CA that affects up to 20.6% of patients. QRS duration and IVS thickness are independently associated with PPM implantation. A PPM implantation at 12 months model was devised and validated to identify patients with CA at higher risk of requiring a PPM and who require closer follow-up.

Tc-99m labelled bone scintigraphy in suspected cardiac amyloidosis

AIMS

To perform evaluation of widely embraced bone scintigraphy-based non-biopsy diagnostic criteria (NBDC) for ATTR amyloid cardiomyopathy (ATTR-CM) in clinical practice, and to refine serum free light chain (sFLC) ratio cut-offs that reliably exclude monoclonal gammopathy (MG) in chronic kidney disease.

METHODS AND RESULTS

A multi-national retrospective study of 3354 patients with suspected or histologically proven cardiac amyloidosis (CA) referred to specialist centres from 2015 to 2021; evaluations included radionuclide bone scintigraphy, serum and urine immunofixation, sFLC assay, eGFR measurement and echocardiography. Seventy-nine percent (1636/2080) of patients with Perugini grade 2 or 3 radionuclide scans fulfilled NBDC for ATTR-CM through absence of a serum or urine monoclonal protein on immunofixation together with a sFLC ratio falling within revised cut-offs incorporating eGFR; 403 of these patients had amyloid on biopsy, all of which were ATTR type, and their survival was comparable to non-biopsied ATTR-CM patients (p = 0.10). Grade 0 radionuclide scans were present in 1091 patients, of whom 284 (26%) had CA, confirmed as AL type (AL-CA) in 276 (97%) and as ATTR-CM in only one case with an extremely rare TTR variant. Among 183 patients with grade 1 radionuclide scans, 122 had MG of whom 106 (87%) had AL-CA; 60/61 (98%) without MG had ATTR-CM.

CONCLUSION

The NBDC for ATTR-CM are highly specific [97% (95% CI 0.91-0.99)] in clinical setting, and diagnostic performance was further refined here using new cut-offs for sFLC ratio in patients with CKD. A grade 0 radionuclide scan all but excludes ATTR-CM but occurs in most patients with AL-CA. Grade 1 scans in patients with CA and no MG are strongly suggestive of early ATTR-type, but require urgent histologic corroboration.

Screening approaches to cardiac amyloidosis in different clinical settings: Current practice and future perspectives

Cardiac amyloidosis is a serious and progressive infiltrative disease caused by the deposition of amyloid fibrils in the heart. In the last years, a significant increase in the diagnosis rate has been observed owing to a greater awareness of its broad clinical presentation. Cardiac amyloidosis is frequently associated to specific clinical and instrumental features, so called "red flags", and it appears to occur more commonly in particular clinical settings such as multidistrict orthopedic conditions, aortic valve stenosis, heart failure with preserved or mildly reduced ejection fraction, arrhythmias, plasma cell disorders. Multimodality approach and new developed techniques such PET fluorine tracers or artificial intelligence may contribute to strike up extensive screening programs for an early recognition of the disease.

826 NEW THERAPEUTIC PERSPECTIVES IN CARDIAC AMYLOIDOSIS

Man, 72 years old, smoker, hypertensive and dyslipidemic, came to our clinic suspected of heart disease with a hypertrophic phenotype. In anamnesis there was a recent hospitalization for heart failure in the course of undated atrial fibrillation. During hospitalization because of the presence of antero-septal and lateral QS complexes, a coronary disease was excluded by coronary angiography while the echocardiogram showed a left ventricle with moderate concentric wall thickening, LVEF 38% with a restrictive transmitral pattern. The patient was discharged on therapy with ramipril, bisoprolol, canrenone, furosemide and rivaroxaban with an electrical cardioversion program which had been subsequently ineffective.

At the time of the first evaluation the patient was symptomatic of dyspnea in functional class NYHA III, he also reported in anamnesis a progressive reduction of exercise tolerance for about two years and a previous surgery for bilateral carpal tunnel syndrome 5 years earlier.

The echocardiogram showed concentric parietal thickening in the presence of granular sparkling, apical sparing, thickening of the valvular apparatus and reduced GLS (- 12%) which led to a suspect of cardiac amyloidosis.

To complete the diagnosis, the patient underwent: total-body bone scan with 99-Tc-DPD (Perugini score = 2); assay of serum kappa and lambda light chains (negative), serum and urinary immunofixation (negative), NT-proBNP (980 pg / mL) and a determination of troponin I (32 ng / L) which showed a picture of transthyretin cardiac amyloidosis. The genetic sampling confirmed the presence of the Ile68Leu transthyretin mutation and a neurological evaluation with electromyography ruled out a peripheral polyneuropathy.

During follow-up the patient presented a worsening of clinical and instrumental pattern despite the progressive uptitration of diuretic therapy and the addition of metolazone with a simultaneous deterioration of left ventricular dysfunction (LVEF 30%) at echocardiogram.

Therefore, the patient's case and possible therapeutic strategies were discussed collectively as it was not possible to access conventional therapies for cardiac amyloidosis with Tafamidis, Inotersen and Patisiran due to the contextual functional class NYHA&gt; II and the absence of polyneuropathy, not it was possible to undertake biventricular resynchronization in the absence of intraventricular block or to implement therapy for heart failure with reduced ejection fraction due to intolerance. As a last option, implantation of a cardiac contractility modulation device (CCM) was proposed and performed via right subclavicular.

At the successive follow-up after implantation, the patient showed a slight clinical and instrumental improvement and it was possible to reduce the diuretic dose, discontinuing metolazone. The echocardiogram also showed a slight increase in LVEF (35%).

The long-term outpatient evaluation of the patient is currently underway with the aim of undertaking specific therapy with Tafamidis if the prescription criteria are met. Family screening has started.

Conclusion

the present clinical case represents an example of the application of alternative and potentially effective therapeutic strategies in patients with cardiac amyloidosis not susceptible to conventional pharmacological treatments.

786 SYSTOLIC ANTERIOR MOVEMENT OF MITRAL VALVE: NOT ONLY HYPERTROPHIC CARDIOMYOPATHY, BUT ALSO CARDIAC AMYLOIDOSIS

A 71 years-old man was diagnosed with lambda light chain multiple myeloma evolving from monoclonal gammopathy of unknown significance during hematological follow-up. Serum creatinine and blood urea were normal, but proteinuria was significant. A subsequent renal biopsy showed amyloid deposits in renal glomeruli. He had no comorbidities or previous cardiologic history. To provide a complete diagnostic work-up, an echocardiogram was performed, showing marked and asymmetric left ventricular hypertrophy (interventricular septum diastolic thickness IVSd 15 mm) with dynamic left ventricular outflow tract obstruction (LVOTO) due to an incomplete systolic anterior motion (SAM) of mitral valve. ECG showed sinus rhythm with 1st degree atrio-ventricular block; notably, there was no electrocardiographic sign of left ventricular hypertrophy. Therefore, a Cardiac Magnetic Resonance (CMR) was performed, showing left ventricular hypertrophy (interventricular septum thickness 15 mm) with normal contractility. Mild left atrial enlargement and thickening of the interatrial septum were found, together with mild circumferential pericardial effusion. No perfusion defects were recorded, but late gadolinium enhancement (LGE) pattern was not assessable because of difficult myocardial signal nulling point. These findings were consistent with cardiac amyloidosis (CA). By the time, histological demonstration of amyloid was mandatory, so an endomyocardial biopsy was performed. Amyloid deposits were found to be in the myocardial interstitial space and into the myocardial vessel walls. Immunohistochemical staining revealed diffuse and high reactivity for lambda free light chains and moderate reactivity for kappa chains. No transthyretin was found in the specimens.

Finally, a diagnosis of AL amyloidosis with cardiac and renal involvement associated with lambda light chain multiple myeloma was made and chemotherapy with bortezomib, thalidomide and dexamethasone (VTD) was started. During the cardiologic follow-up, three syncope with prodromal symptoms have occurred. In all these circumstances, no arrhythmias were found at prolonged ECG Holter monitoring. Echocardiogram showed a progression of the dynamic outflow obstruction to 80 mmHg and increasing mitral regurgitation associated with complete systolic anterior motion of the valve. Given the echocardiographic features and the clinical events, we performed a genetic blood test which excluded sarcomeric genes mutations. Also, familial screening with ECG and echocardiogram was negative.

A better management of pharmacological therapy, together with avoidance of hypovolemia and supportive treatment of anemia finally relieved patient's symptoms.

Conclusions

we presented this case to underline that, although rare, cardiac amyloidosis can resemble other hypertrophic cardiomyopathies with left ventricular outflow tract obstruction due to SAM of the mitral valve and irregular septal hypertrophy, caused by amyloid deposits. Most of these cases are seen in the senile transthyretin type, but sometimes they are observed in AL patients. Nowadays, it is crucial to diagnose these patients correctly as early treatment is critical for survival in this population.

172 CLINICAL AND PROGNOSTIC IMPLICATIONS OF RV UPTAKE WITH RADIONUCLIDE SCINTIGRAPHY IN TRANSTHYRETIN CARDIAC AMYLOIDOSIS

Aims

The prognostic role of bone tracer uptake in transthyretin cardiac amyloidosis (ATTR-CA) is controversial. The study investigated the potential prognostic significance of biventricular (BiV) uptake in ATTR-CA.

Methods

Consecutive ATTR-CA patients who had cardiac scintigraphy with acquisition of planar and single-photon emission computed tomography (SPECT) images from the National Amyloidosis Centre (NAC) and four Italian centres were included. Planar BiV uptake was defined in presence of right ventricle (RV) uptake and graded in combination with SPECT imaging. The primary outcome was all-cause mortality.

Results

Among 1422 patients with ATTR-CA, BiV uptake was found in 85% of cases on planar scintigraphy and in 100% of cases on SPECT images. During a median follow-up of 39 months, BiV uptake at planar scintigraphy was associated with a higher all-cause mortality compared to isolated LV uptake (40.5% vs 10.7%, p&lt;0.001), whereas the Perugini scale was not (p=0.27 in grade 2 vs 3). At multivariable analysis, RV uptake at planar scintigraphy leading to BiV uptake (HR 2.80, p=0.001), together with higher age at diagnosis (HR 1.03, p=0.001), V122I TTR variant (HR 1.60, p=0.001), NAC ATTR Stage (HR 1.29, p=0.003), E/e’ (HR 1.02, p=0.044), right atrium area index (HR 1.04, p=0.018) and GLS (HR 1.05, p=0.003) were independently associated with all-cause death. At time-dependent ROC curve analysis, the addition of planar BiV uptake to the NAC stage resulted in improved accuracy of the model for prediction of all-cause death (from AUC 0.74 to 0.79; p&lt;0.001).

Conclusions

Planar RV uptake leading to BiV uptake identified ATTR-CA patients with worse outcome, potentially serving as a novel prognostic marker.

[Ten questions about transthyretin amyloidosis]

Systemic amyloidosis is a hereditary or acquired disease characterized by deposition of amyloid insoluble fibrils into body organs and tissues, causing structural abnormalities and organ dysfunction, i.e. heart failure. This disease is classified according to the precursor protein involved; immunoglobulin light chains, transthyretin and apolipoprotein A1 underlie the cardiac involvement. Amyloid cardiomyopathy is characterized by symmetric biventricular hypertrophy, preserved systolic function, and pronounced diastolic dysfunction. Although transthyretin-related cardiac amyloidosis has always been considered a rare disease, in the last few years it has been found to be one of the most common causes of hypertrophic cardiomyopathy, thanks to better diagnostic algorithms and considerable improvements in cardiac imaging. Achieving an early diagnosis is a challenge for the modern cardiologist since new disease-modifying therapies have been developed in recent years. This article aims to answer to the main questions about transthyretin-related cardiac amyloidosis: when to suspect it, how to diagnose it and how to treat it.

334 Hereditary transthyretin amyloidosis: main features and profiles of different clinical phenotypes

Aims

Hereditary transthyretin-related amyloidosis (h-ATTR) is a systemic infiltrative disease caused by a single amino acid mutation on the transthyretin (TTR) gene, which destabilizes the protein and can determine its deposition on multiple organs, including heart and peripheral nervous system. We aimed to characterize and compare clinical, instrumental, and prognostic features of patients affected by h-ATTR by dividing the population into the disease’s main phenotypes (unaffected carriers, cardiac, neurological or mixed phenotype).

Methods and results

Two hundred and eighty-five subjects of a single-centre cohort with a recognized pathogenic mutation on TTR gene were retrospectively included in the analysis. Phenotypes of disease were defined at baseline. Neurological phenotype (NP) was defined according to sensorimotor and/or autonomic dysfunction, while cardiac phenotype (CP) was defined in the presence of unexplained maximum wall thickness &gt;12 mm and other typical echocardiographic findings. Unaffected carriers (UC) and mixed phenotypes (MP) presented none or both of the above-mentioned features, respectively. Two hundred and ten patients showed clinical signs of the disease, 37 (13%) with CP, 65 (23%) with NP and 108 (38%) with MP, while 75 subjects (26%) were UC. Ile68Leu was the most represented mutation (96 subjects, 34%), followed by Val30Met (21%) and Glu89Gln (13%). NP patients (mostly Val30Met) had mPND score &gt;1 in 45% of patients, were younger at diagnosis (mean 47 years, P &lt; 0.001 vs. CP/MP), and sex was equally distributed. In contrast, CP patients were older at diagnosis (mean 70 years, P &lt; 0.001 vs. CP/MP), predominantly male (as well as in MP) with a higher incidence of tunnel carpal syndrome and a shorter time interval between onset of symptoms and diagnosis (mean 17 months, P &lt; 0.001 vs. CP/MP). NYHA class, ECG findings, left ventricular wall thickness, and ejection fraction did not significantly differ between CP and MP. After a mean follow-up of 59 months, 98 (34%) patients died. On a Kaplan–Meier survival analysis, mean survival times were 208, 123, 150, and 95 months for UC, CP, NP, and MP, respectively, with a statistically significant difference in affected patients between NP and MP (P = 0.012).

Conclusions

H-ATTR is a rare systemic disorder whose natural history, including age of onset, clinical characteristics, and instrumental findings, is strongly influenced by primary phenotypes, ranging from the excellent prognosis of unaffected carriers to the inauspicious outcome of mixed phenotypes.

351 Prevalence and prognostic significance of RV uptake (biventricular uptake) at planar scintigraphy in patients with ATTR cardiac amyloidosis

Aims

The validation of cardiac scintigraphy with bone tracers for nonbiopsy confirmation of transthyretin cardiac amyloidosis (ATTR-CA) has revolutionized the diagnosis of this condition. While most studies focused on left ventricle (LV) uptake, the significance of bone tracers uptake in the right ventricle (RV) leading to biventricular (BiV) uptake has not been investigated so far. BiV uptake at planar scintigraphy might reflect a more advanced ATTR-CA. To estimate the prevalence of BiV uptake and its potential prognostic role in ATTR-CA.

Methods and results

Multicentre, retrospective, observational study performed among four Italian referral centres for CA. Data of ATTR-CA patients who underwent bone tracers scintigraphy with acquisition of planar and SPECT imaging between November 2014 and June 2020 at participating centres were centrally revised. ATTR-CA was diagnosed according to the Gilmore’s algorithm. LV uptake was assessed by Perugini visual scale. RV uptake was defined as: 0 = absent, 1 ≤ bone uptake, 2 = equal to bone uptake, and 3 ≥ bone uptake. Images were independently assessed by six experienced operators, blinded to all patients’ data. Cardiological data included clinical examination, ECG, echocardiography and blood tests. The primary outcome was a composite of cardiac death and hospitalization for heart failure. Of the 124 patients with ATTR-CA included in this analysis, 93 (75%) had BiV uptake at planar scintigraphy and all had RV free wall uptake confirmed at SPECT imaging. The prevalence of planar BiV uptake increased along with the LV Perugini grade: 14% in Perugini grade 1, 70% in Perugini grade 2, and 92% in Perugini grade 3. Compared to those with planar LV uptake, patients with planar BiV uptake were older (81 vs. 77 years, P = 0.006), more frequently in NYHA ≥3 (32% vs. 10%, P = 0.018), had increased NT-proBNP values (4293 vs. 2492 pg/ml, P = 0.046), LV wall thickness (18 vs. 17 mm, P = 0.007). They had higher rates of LV ejection fraction &lt;50% (42% vs. 10%, P = 0.001) and lower TAPSE (16 vs. 20 mm, P = 0.048). At 18 months, patients with BiV uptake experienced the primary endpoint more frequently than those with LV uptake (P = 0.021, Figure), with the highest risk observed in patients with grade 2–3 RV uptake (P = 0.010). The LV Perugini grade did not affect prognosis (P = 0.20). At multivariate analysis, NYHA ≥3, eGFR &lt;60 ml/min and BiV uptake had independent prognostic value (HR 8.0, P = 0.007; HR 2.1, P = 0.025; HR 1.7, P = 0.007; respectively).

Conclusions

The presence of BiV uptake at planar scintigraphy identified ATTR-CA patients at worse cardiovascular outcome, potentially serving as novel marker for prognostic stratification in this population.

199 Lower aortic valve calcium scores by computed tomography scan. A potential new red flag of concomitant cardiac amyloidosis in patients with severe aortic stenosis

Aims

Cardiac amyloidosis (CA) and degenerative aortic stenosis (AS) are two diseases often combined but the diagnosis of both these conditions is challenging because these two illnesses share common echocardiographic characteristics. Different predictors have been proposed in the last few years, including clinical, ECG-graphic, and echocardiographic features. To identify a new marker of concomitant CA in patients with severe AS using computed tomography scan (CT).

Methods and results

Fifty-five patients with severe AS and suspicion of concomitant CA were retrospectively enrolled. Patients with a bicuspid aortic valve, previous aortic valve replacement, or an incomplete diagnostic workup for CA were excluded. Thirty-three patients underwent CT-scan and were included in the final analysis. None of the patients had at laboratory tests suspicion for AL amyloidosis; 12 patients (AS-CA) had positive 99 m Tc-DPD bone scintigraphy (two with visual score 1, eight score 2 and two score 3), 21 patients (AS-alone) had negative bone scintigraphy (visual score 0). AS-CA patients had a median age of 85.5 years (vs. 82) with only one female patient (vs. 8 in the AS-alone group). AVA indexed were almost comparable between AS-CA and AS-alone groups (0.4 vs. 0.3 mm2/m2, P = 0.25). Stroke volume evaluated by pulsed Doppler, maximum and mean gradient were significatively lower in AS-CA group (respectively 30 vs. 41 ml/m2, P = 0.017, 62 vs. 74 mmHg, 0.038 and 33 vs. 46 mmHg, P = 0.022) with a higher percentage of paradoxical low flow-low gradient aortic stenosis in AS-CA group (7 patients, 58% vs. 3 patients in AS-alone 14%, P = 0.027), in line with the literature. ECG at first presentation in AS-CA group showed atrial fibrillation in eight patients (67%), vs. two patients in the AS-alone group (10%), and lower QRS voltages (peripheral QRS score 40 mV vs. 51 mV, P-value = 0.017; total QRS score 113 mV vs. 155 mV, P-value = 0.005). The echocardiogram showed a more thickened IVS and PW in AS-CA patients (17 vs. 15 mm, P = 0.05 and 15 vs. 14 mm, P = 0.013), an increased left ventricular mass (441 vs. 356 g, P = 0.036) with a reduction of longitudinal systolic function (septal S wave at TDI 4.4 vs. 5.2 cm/s, P = 0.026, lateral S wave 4.1 vs. 5.6 cm/s, P = 0.024) and a lower myocardial contraction fraction (12% vs. 14%, P = 0.036). CT-aortic valve calcium was valued and quantified by an experienced operator. A statistically significant difference between AS-CA and AS-alone groups was observed in calcium score (3345 vs. 4785 Hounsfield units, P = 0.037) calcium volume (2411 vs. 3626 mm2, P = 0.03) and calcium mass (687 vs. 1147 g, P = 0.023).

Conclusions

This study is the first to our knowledge to use relative aortic valve calcium score evaluation from CT imaging to define patients with severe AS with or without concomitant CA in addition to the classical clinical, ECG graphic, and echocardiographic features. CT-aortic valve calcium burner was significatively lower in patients with concomitant CA.

172 Two mutations, one patient: which phenotype?

Methods and results

Woman, 55 years old, she has as comorbidity high blood pressure and mild obesity. She came at our attention to perform screening cardiological exams after her brother, who was affected by amyloidotic TTR-related cardiomyopathy with Val30Met mutation, died for sudden cardiac death. At the first evaluation the patient is completely asymptomatic, she has not angor, dyspnoea and heartbeat. The ECG and echocardiography were negative for amyloidotic signs of heart involvement. The Tc-99-DPD scintigraphy showed no cardiac uptake (visual score = 0). To complete the diagnostic path the patient had been evaluated by a neurologist with electromyography, which was negative, and genetic test, which confirmed the presence of Val30Met mutation of TTR-gene. For this last outcome we decided to follow the patient at our clinics. In the following years the patient developed a progressive reduction of exercise tolerance and symmetric negative T waves in anterolateral and inferior lead at ECG. The echocardiogram showed a progressive medio-apical septal hypertrophy. To exclude an ischaemic cause the patient made a stress myocardial scintigraphy, which was negative for ischaemic signs, and she underwent to cardiac MRI which showed a septal thickness of 16 mm without amyloidotic radiological signs in T1-weighted and LGE sequences. For this reason, we suspected that the patient had a hypertrophic cardiomyopathy and she had been undergone another time to genetic test which confirmed the Val30Met TTR-mutation and MYBPC3 mutation. Usually, this last gene mutation for myosin binding protein C is associated with late-onset hypertrophic cardiomyopathy. Into account the new diagnosis and her sudden cardiac death family history we calculated the patient’s HCM-risk score which was under 4%, so that we did not undergo the patient to ICD implantation.

Conclusions

The case report is a rare example of coexistence of the transthyretin gene mutation and myosin binding protein C in the same patient. In this case to perform a correct diagnosis, it is crucial use an integrated multimodal approach including ECG, echocardiography and cardiac MRI.

Analysis of characteristics and prognostic impact of phenotypes in hereditary ATTR

Background

Hereditary transthyretin-related amyloidosis (h-ATTR) is a systemic infiltrative disease caused by a single amino acid mutation on the transthyretin (TTR) gene, which destabilizes the protein and can determine its deposition on multiple organs, including heart and peripheral nervous system.

Purpose

We aimed to characterize and compare clinical, instrumental, and prognostic features of patients affected by h-ATTR by dividing the population into the disease's main phenotypes (unaffected carriers, cardiac, neurological or mixed phenotype).

Methods

Two hundred and eighty-five subjects of a single-centre cohort with a recognized pathogenic mutation on TTR gene were retrospectively included in the analysis. Phenotypes of disease were defined at baseline. Neurological phenotype (NP) was defined according to sensorimotor and/or autonomic dysfunction, while cardiac phenotype (CP) was defined in the presence of unexplained maximum wall thickness &gt;12 mm and other typical echocardiographic findings. Unaffected carriers (UC) and mixed phenotypes (MP) presented none or both of the above-mentioned features, respectively.

Results

Two hundred and ten patients showed clinical signs of the disease, 37 (13%) with CP, 65 (23%) with NP and 108 (38%) with MP, while 75 subjects (26%) were UC. Ile68Leu was the most represented mutation (96 subjects, 34%), followed by Val30Met (21%) and Glu89Gln (13%). NP patients (mostly Val30Met) had mPND score &gt;1 in 45% of patients, were younger at diagnosis (mean 47 years, p&lt;0,001 vs CP/MP), and sex was equally distributed. In contrast, CP patients were older at diagnosis (mean 70 years, p&lt;0,001 vs CP/MP), predominantly male (as well as in MP) with a higher incidence of tunnel carpal syndrome and a shorter time interval between onset of symptoms and diagnosis (mean 17 months, p&lt;0,001 vs CP/MP). NYHA class, ECG findings, left ventricular wall thickness and ejection fraction did not significantly differ between CP and MP. After a mean follow-up of 59 months, 98 (34%) patients died. On a Kaplan-Meier survival analysis, mean survival times were 208, 123, 150 and 95 months for UC, CP, NP and MP, respectively, with a statistically significant difference in affected patients between NP and MP (p=0.012).

Conclusions

H-ATTR is a rare systemic disorder whose natural history, including age of onset, clinical characteristics and instrumental findings, is strongly influenced by primary phenotypes, ranging from the excellent prognosis of unaffected carriers to the inauspicious outcome of mixed phenotypes.

Funding Acknowledgement

Type of funding sources: None.

A clinical and instrumental study of heart failure in amyloidotic cardiomyopathy

Background

Heart failure (HF) is one of the main features of amyloidotic cardiomyopathy (AC) and it is supposed to carry important prognostic implications. Despite the intrinsic etiologic heterogeneity of AC, HF has been mainly attributed to diastolic dysfunction, but the role played by the different amyloid subtypes of AC and by the clinical and hemodynamic factors in the pathophysiology of HF remains unclear.

Objectives

We aimed to assess the hemodynamic profile and outcome of patients with or without advanced HF (defined as NYHA class III-IV) at the time of first evaluation in light-chain (AL), hereditary transthyretin-related (h-ATTR) and non-mutant transthyretin-related (wt-ATTR) AC.

Methods

Among the 411 patients diagnosed with AC (156 AL, 131 h-ATTR, 124 wt-ATTR) at our Centre between 1990–2019, we analyzed central hemodynamic data, echocardiographic, clinical, ECG details and survival of the whole cohort. Cox regression analysis was used to stratify prognosis.

Results

112 (27%) patients presented advanced HF at first evaluation and frequently showed severe symmetric left ventricle wall thickening (higher values in h-ATTR), non-dilated left ventricle, preserved ejection fraction and pathological global longitudinal strain and/or myocardial contraction fraction.

At ECG, a significantly lower QRS voltage was present in advanced HF patients. Hemodynamically, elevated filing pressures on both cardiac sides were present in patients in NYHA III-IV class of the three etiologies. Overall survival at 2 years was 35% for AL, 83% for h-ATTR, 65% for wt-TTR. H-ATTR and wt-TTR were favorable predictors of survival, while reduced cardiac index and elevated filling pressures were indepedently associated with higher mortality.

Conclusions

The characterization of hemodynamic profile plays a central role in predicting the natural history of AC, since reduced stroke volume and elevated filling pressures are the best predictors of mortality, reflecting a physiopathological restrictive model of the disease. Conversely, left ventricular ejection fraction is rarely abnormal and it is not a reliable marker of poor prognosis, especially in the early stages of the disease. AL amyloidosis shows the worst outcome probably due to a combination of the underlying illness and light chains cardiotoxicity.

LVEF and cardiac index in HF

Funding Acknowledgement

Type of funding source: None