Prognostic implications of biventricular uptake of bone tracers at planar scintigraphy in transthyretin cardiac amyloidosis

Background

The prognostic role of bone tracer uptake in transthyretin cardiac amyloidosis (ATTR-CA) is controversial. A further characterization of cardiac retention measured by Perugini scale with differentiation between biventricular (BiV) and isolated left ventricle (LV) uptake has never been attempted previously.

Purpose

The study investigated the potential prognostic significance of BiV uptake in ATTR-CA.

Methods

In this multicentre, observational study, we analysed data of ATTR-CA patients who underwent bone tracer scintigraphy with acquisition of both planar and single photon emission computed tomography (SPECT) imaging. Cardiac uptake was defined according to the Perugini visual scale. Planar BiV uptake was defined according to right ventricle (RV) uptake: 0= absent, 1= < bone, 2= equal to bone, and 3= > bone and confirmed by SPECT imaging. The primary outcome was a composite of cardiac death or hospitalization for heart failure. The secondary outcome was all-cause mortality.

Results

All 124 ATTR-CA patients enrolled had LV and RV free wall uptake on SPECT images. Of them, 93 (75%) had BiV uptake visible on planar scintigraphy. BiV uptake was found in 14%, 70%, and 92% of Perugini grade 1, 2 and 3 respectively. Compared to those with isolated LV uptake, patients with BiV uptake were older (81 vs 77 years, p=0.006) and more frequently in NYHA≥3 (32% vs 10%, p=0.018). During a median follow-up of 21 months, BiV uptake was associated with a greater occurrence of the primary outcome compared to isolated LV uptake (40% vs 19%, p=0.021), whereas the Perugini scale was not (p=0.2) (Figure 1). At multivariable analysis, NYHA class ≥3 (hazard ratio [HR] 8.1, p=0.007), eGFR <60 ml/min (HR 2.1, p=0.025) and higher degree of RV uptake (HR 1.69, p=0.007) emerged as independent prognostic parameters. In an external cohort of 463 ATTR-CA patients with a median follow-up of 30 months, planar BiV uptake was independently associated with all-cause mortality, with an incremental risk in higher grades of RV uptake (p<0.001) (Figure 1).

Conclusions

The presence of BiV uptake at planar scintigraphy identified ATTR-CA patients with worse cardiovascular and global outcomes (Figure 2), potentially serving as a novel prognostic marker.

Funding Acknowledgement

Type of funding sources: None.

Size matters - redefining sex differences among patients with transthyretin amyloid cardiomyopathy – have we been wrong all along?

Background

Transthyretin amyloid cardiomyopathy (ATTR-CM) is most often diagnosed in men (1–5). The few available studies suggest affected women have a more favourable cardiac phenotype (5–8), but remain unclear regarding differences in outcomes.

Objectives and methods

To characterise sex differences among consecutive patients with non-hereditary and two prevalent forms of hereditary ATTR-CM diagnosed over a 20-year period at our specialist centre through analysis of deep phenotyping at presentation, changes on serial echocardiography and overall prognosis.

Results

In total, 1732 patients were studied, comprising: 1095 with wild-type (wt)ATTR-CM; 206 with T60A-hATTR-CM; and 431 with V122I-hATTR-CM. Female prevalence was greater in T60A-hATTR-CM (29.6%) and V122I-hATTR-CM (27.8%) compared to wtATTR-CM (6%). At presentation, females were 3.3 years older than males (81.9 vs 77.8 years for wtATTR-CM; 68.7 vs 65.1 years for T60A-hATTR-CM; 77.1 vs 74.9 years for V122I-hATTR-CM). At diagnosis, non-indexed measures of wall thickness were significantly greater in males (interventricular septum in diastole (IVSd) of 17.13mm in males & 16.15mm in females; p<0.001). When indexed for body surface area (BSA), we observed that the mean indexed IVSd was fairly constant in males throughout the study period, but in females, had a tendency to decrease over the same study period. Furthermore, BSA significantly influenced measures of disease severity. When indexed for BSA, overall structural and functional phenotype was similar between sexes; the few observed significant differences including indexed IVSd (9.62mm/m2 in females & 8.88mm/m2 in males; p<0.001), indexed left ventricular (LV) end-diastolic volume (35.07ml/m2 in females & 41.05ml/m2 in males; p<0.001) and indexed LV end-systolic volume (17.95ml/m2 in females & 21.74ml/m2 in males; p<0.001) suggested a mildly worse phenotype in females. No significant differences were observed in disease progression on serial echocardiography and mortality across the overall population (p=0.459) and when divided by genotype (p=0.730 for wtATTR-CM; p=0.161 for T60A-hATTR-CM; p=0.056 for V122I-hATTR-CM).

Conclusion

This study of a well-characterized large cohort of ATTR-CM patients, contrary to previous dogmas, did not demonstrate overall differences between sexes in either clinical phenotype, when indexed, or with respect to disease progression and prognosis. The analysis highlighted the deficiencies in using non-indexed values which can not only lead to the inaccurate perception of a milder clinical phenotype in women compared to men, but has been shown to result in female patients presenting at an older age and with a worse phenotype compared to men. These findings indicate the need for revision of existing clinical guidelines regarding awareness and diagnosis of ATTR-CM in women, and modification of clinical trials which currently use single non-indexed threshold for wall thickness as key inclusion criterion.

Funding Acknowledgement

Type of funding sources: Foundation.

A multi-modality, multi-parametric phenotyping study of transthyretin amyloid cardiomyopathy associated with the p.V142I TTR variant

Introduction

Transthyretin amyloid cardiomyopathy (ATTR-CM) is an increasingly recognised cause of heart failure. 3–4% of individuals of African descent carry a transthyretin gene mutation encoding the p.V142I variant, a powerful risk factor for development of variant ATTR-CM. This equates to 1.6 million potential carriers in the USA alone. We report findings from a multi-parametric, multi-modality phenotyping study of p.V142I ATTR-CM.

Hypothesis

The phenotype of p.V142I variant ATTR-CM is an aggressive form of ATTR CM.

Methods

A retrospective phenotyping study of 395 patients with p.V142I-ATTR-CM at our national referral centre was conducted. Patients underwent evaluation at the centre at time of diagnosis, including clinical and functional assessment, echocardiography, biomarker analysis; a subgroup had cardiac magnetic resonance imaging. 395 wild type ATTR-CM patients matched for independent predictors of prognosis (NAC Disease Stage, age, decade of first presentation) were used as a comparator group.

Results

Average age of pV142I ATTR-CM patients was 75.8 years. There was significant functional impairment (38.2% of cases NHYA ≥ III, mean 6 minute walk test distance 272m). Significant impairment of echocardiographic parameters was seen; mean LVEF 43%, global longitudinal strain −9.1%, TAPSE 14.2mm, E/E prime 17.4, E/A ratio 2.47 with high frequency of at least moderate mitral (44%) and tricuspid regurgitation (51%). Median NT-proBNP was 3165 ng/L (IQR 4224). Arrhythmias were common with 17.4% of patients having a bradyarrhythmia, 26.1% having atrial fibrillation/flutter, and 5.6% having a pacemaker at presentation. Uni and multivariate cox regression analysis identified serum troponin, tricuspid regurgitation, LVEF, TAPSE and lower systolic blood pressure as independent predictors of prognosis. Prognostic parameters were statistically significantly worse and five year survival by Kaplan Meier analysis was significantly reduced when compared to matched WT ATTR-CM patients (p<0.05) (Figure 1).

Mean serum high sensitivity troponin T and extracellular volume (ECV) by cardiac magnetic resonance (CMR) was higher in p.V142I ATTR-CM than WT ATTR-CM cases (94 ng/L vs 74.2 ng/L, p<0.05, 58% vs 55%, p<0.05). Interventricular wall thickness however was lower in p.V142I ATTR-CM than matched WT cases (17.2 mm vs 16.8 mm).

Conclusion

p.V142I ATTR-CM is an aggressive phenotype, with significant functional impairment, burden of regurgitant valvular disease and systolic impairment resulting in poor survival.

Patients with p.V142I ATTR-CM had a higher burden of amyloid infiltration as measured as shown by ECV measurements on CMR, higher serum troponin and lower wall thickness when compared to a matched cohort of WT ATTR-CM patients. This novel observation suggests a unique disease mechanism that is more cardiotoxic which results in myocyte loss and myocardial thinning as opposed to myocyte hypertrophy.

Funding Acknowledgement

Type of funding sources: None.

Progression, regression and redefining the treatment response – cardiac magnetic resonance with T1 and extracellular volume mapping in cardiac light-chain amyloidosis

Background

The presence and severity of cardiac involvement in AL amyloidosis is the main driver of prognosis [1]; patients with symptomatic heart failure frequently die within 6 months [1] but median survival has nearly doubled over the past decade, mainly due to significant improvements in chemotherapy. The haematological response to chemotherapy is principally evaluated with serial measurements of serum-free light-chains (FLC) [2]. The cardiac response to chemotherapy is assessed through changes in serum concentrations of brain natriuretic peptides (including NT-proBNP) and echocardiographic parameters [3–5]. Neither are able to directly measure cardiac amyloid burden. Cardiovascular magnetic resonance (CMR) with extra-cellular volume (ECV) mapping can measure the extent cardiac amyloid infiltration [6].

Aims

We investigated the ability of CMR to: 1) measure changes in response to chemotherapy; 2) assess the correlation between haematological response (HMR) and changes in cardiac amyloid; 3) assess the association between changes in cardiac amyloid and prognosis over and above existing predictors.

Methods

In total, 176 patients with cardiac light-chain amyloidosis treated with chemotherapy were assessed with FLC, NT-proBNP and CMR with ECV mapping at baseline (before chemotherapy), 6-months, 12-months & 24-months after commencing chemotherapy. Haematological response was categorized by reductions in FLC as: complete response (CR), very good partial response (VGPR), partial response (PR) or no response (NR). CMR response was categorized by changes in ECV as: progression (≥0.05 increase), stable (<0.05 change) or regression (≥0.05 decrease).

Results

A progressive increase in patients achieving either CR or VGPR was observed at each time point (61% of patients at 6-months, 71% at 12-months and 80% at 24-months). At 6-months, CMR regression was observed in 3% (all had either CR or VGPR) and progression in 32% (61% had either PR or NR; 39% had either CR or VGPR). At 1-year, CMR regression was observed in 22% (all had either CR or VGPR); progression in 22% (63% had either PR or NR; 37% had either CR or VGPR). At 2-years, CMR regression was observed in 38% (all had CR/VGPR); progression in 14% (80% had either PR or NR; 20% had either CR or VGPR). During follow-up (40±15 months), 36 (25%) patients died. CMR response at 6-months predicted death (progression HR 3.821; 95% CI 1.950–7.487; p<0.001) and remained independently associated with prognosis after adjusting for haematological response, NT-proBNP and longitudinal strain on echocardiography (p<0.01).

Conclusions

CMR demonstrates that cardiac amyloid deposits frequently regress following chemotherapy, but only in patients who achieve CR or VGPR, highlighting the need for deep haematological response. Changes in amyloid burden (ECV) predict outcomes after adjusting for known predictors, showing the crucial role of CMR in redefining treatment response.

Funding Acknowledgement

Type of funding sources: Foundation.

Regression of cardiac amyloid deposits with novel therapeutics: reaching new frontiers in cardiac ATTR amyloidosis

Background

Cardiac involvement is the main driver of outcome in ATTR amyloidosis. Advances in therapeutics hold potential in transforming the course of the disease but the impact on cardiac amyloid load is unknown. The aim of this study was to evaluate the impact of patisiran, a new double stranded RNA based gene silencing therapy and a stabilizer, diflunisal, on cardiac amyloid load as measured by CMR and T1 mapping, in patients with ATTR amyloidosis.

Methods and results

Thirty-two patients with hereditary cardiac amyloidosis were studied. Sixteen patients received treatment with patisiran, and sixteen control subjects did not receive any disease modifying treatment. Patients were assessed with echocardiogram, CMR, NT-proBNP and six-minute walk time measurements at baseline and at 1 year (Mean interval 11.45±3.08 months in treatment group, mean interval 12.82±5.06 months in the control group). CMR analysis comprised LV volumes, T1 mapping to measure the extracellular volume (ECV) occupied by amyloid, T2 mapping and late gadolinium enhancement imaging. At 1-year follow-up, there was a substantial reduction in cardiac amyloid burden, in keeping with cardiac amyloid regression in 45% of patients on treatment. Overall the treatment group showed a reduction in ECV at 1 year follow up compared to an increase in ECV at 1 year in the control group (−1.37%, 95% CI: −3.43 to 0.68% versus 5.02%, 95% CI: 2.86% to 7.18% respectively, p<0.001). The treatment group also showed an improvement in change in 6MWT at 1 year follow up compared to 6MWT at 1 year in the control group (−8.12 meters, 95% CI: −50.8 to 34.6 meters in the treatment group versus −132.27 meters, 95% CI: −216 to −48.6 meters in the control group, p=0.002). The treatment group showed a reduction in BNP at 1 year follow up compared to an increase in the control group (−567.87, 95% CI: −1288.90 to 153.15 in the treatment group versus 2004, 95% CI: 12.82 to 3995.45 in the control group, p<0.001). There was no significant difference from baseline and 1-year data between the control and treatment groups for the difference in echocardiographic parameters, native T1, T2. There was a significant reduction in the percentage of injected dose by 99Tc-DPD scintigraphy in treated patients at 1 year compared to baseline.

Conclusions

These findings provide the first compelling evidence of substantial cardiac amyloid regression in ATTR amyloidosis, as well as the potential for CMR to be used to track response in treated patients with ATTR cardiac amyloidosis. Combination therapy with transthyretin knock down and stabilizing agents may well be synergistic given enhanced stoichiometry of stabilizers in the face of much reduced plasma transthyretin concentration.

Funding Acknowledgement

Type of funding source: None

Atrial strain in cardiacATTR amyloidosis from pathophysiology to prognosis: is it time to rethink our approach to disease?

Background

Left atrial (LA) involvement in cardiac ATTR amyloidosis (ATTR-CM) has never being explored. The aim of the study is to characterize the spectrum of changes in LA structure in ATTR-CM, the functional consequences on LA mechanics and the association with mortality.

Methods

We studied 936 patients with ATTR-CM who underwent prospective protocolized evaluations comprising ECG, full echocardiographic assessment, 6MWT, blood biomarkers sampling and survival assessment between 2000 and 2019. Reservoir (LAr), conduit (LAcd) and booster (LAcont) function were assessed according to current guidelines. LA stiffness (LAstiff) was estimated as the ratio between E/e' and LAr. The presence and extent of amyloid infiltration was assessed in two autopsied hearts from patients ATTR-CM with congo red staining and TTR antibodies.

Results

936 patients with ATTR-CM were included, 567 with wtATTR-CM and 346 with hATTR-CM, of whom 246 had the V122I variant and 100 the T60A variant. LA indexed area was similar across the 3 genotypes, whilst LAr, LAcd and LAcont were significantly reduced in V122I patients compared to Wt and T60A patients (LAr: 10.4±6.4 vs 12.8±8.5 vs 8.59±5.7%, p<0.0001; LAcd: 5.6±5.0 vs 6.9±5.7 vs 4.0±3.6%, p<0.0001; LAcont 7.5±4.1 vs 8.2±4.9 vs 6.7±4.2%, p=0.023; in Wt, T60 and V122I respectively). Similarly, LAstiff was significantly worse in V122I compared to Wt and T60A (LAstiff: 2.39±2.62 vs 2.59±4.83 vs 2.96±2.88, p<0.0001, in Wt, T60 and V122I respectively). In the overall population, LAstiff remained independently associated with mortality, after adjusting for rhythm, systolic and diastolic functional parameters, ventricular longitudinal strain, genotypes, clinical variables and NAC staging system (lnLA stiff: HR=1.26, CI: 1.07–1.57; p=0.009). In the overall population, 584 patients were in sinus rhythm and 344 in atrial fibrillation, atrial flutter or atrial tachycardia (non-sinus rhythm group – NSR). Among patients in SR, 21.6% did not show a measurable LA mechanical contraction on strain analysis (LAcont). Patients in SR without LAcont on strain analysis showed similar structural and functional LA changes, NTproBNP, NYHA class, and 6MWT to NSR patients. Mortality of patients in SR with no LAcont was significantly reduced compared to patients in SR with LAcont and similar to patients in AF (Figure 1). On the two autopsies hearts there was extensive amyloid infiltration of TTR type in the atrial wall as confirmed with CR and TTR antibodies (Figure 1).

Conclusions

ATTR-CM is characterized by primary infiltration of the atrial walls with progressive loss of atrial function and increased stiffness. LA stiffness is a strong independent predictor of mortality after adjusting for known predictors. Atrial electro-mechanical dissociation emerged as a distinctive functional phenotype identifying patients in SR with worse prognosis.

Figure 1

Funding Acknowledgement

Type of funding source: None

Global longitudinal strain predicts survival and response in patients with systemic AL amyloidosis. analysis of 915 patients from the ALchemy prospective trial

Background

Cardiac involvement determines prognosis in systemic AL amyloidosis. The extent is assessed by biomarker-based staging systems. This a prospective report of a large cohort of patients assessing the utility of changes in longitudinal function by 2D strain (GLS%), impairment - a hallmark of amyloidosis.

Purpose

To evaluate the prognostic role of GLS% and other echocardiographic parameters in systemic AL amyloidosis.

Methods

915 newly diagnosed patients seen at the UK National Amyloidosis Centre (February 2010–August 2017) were included. All patients underwent 6-monthly comprehensive assessments inclusive of echocardiogram. The European modification of the Mayo 2004 staging was used with Mayo stage III patients stratified into IIIa (NT-proBNP <8500ng/L) and IIIb (NT-proBNP ≥8500ng/L).

Results

653/915 (71.4%) patients had cardiac involvement. Mayo stage 1, 2, 3a and 3b in 144 (15.7%), 302 (33.0%) 344 (37.6%) and 125 (13.7%) respectively. The median NT-proBNP was 2228ng/L and TNT was 0.54ng/ml. The GLS% significantly worsened with increasing Mayo stage (p<0.0001 between GLS% for each Mayo stage). Poorer baseline GLS% associated with significantly worse OS and stratified patients into three groups: GLS% <−12.8%: OS 69.1 months; GLS% −12.8% to −9%: OS 54.5 months; GLS% >−9%: OS 45.3 months (p<0.0001). On univariate analysis, 11/14 parameters predicted survival (LV wall thickness, LV ejection fraction, systolic velocities of the septal (s'sep) and lateral mitral annulus (s' lat), mitral annulus movement at the lateral corner (e' lat), transmitral early peak flow velocity (E) divided by tissue Doppler mitral annular motion velocity (e') – E/e' and mitral annular plane systolic excursion (MAPSE)). Baseline GLS% >−17% was independent of Mayo stage in predicting survival [Mayo II: Hazard ratio (HR) 2.10 (95% CI: 1.12–3.92) p=0.02, Mayo III: HR 3.94 (95% CI: 2.13–7.32) p<0.0001, Mayo IV: HR 7.49 (95% CI: 3.94–14.21) p<0.0001, GLS <17%: HR 2.14 (95% CI: 1.59–2.88) p<0.0001]. At 12 months, only patients in a haematological complete response (CR) had significant improvement in overall GLS% (p=0.02) as well as baso-lateral (p=0.0004) and baso-septal (p=0.0001) GLS% and MAPSE (p=0.002). The OS was significantly better in patients who achieved a minimum absolute improvement in GLS% of 1.5% improvement (not reached in those with improved GLS% vs. 72 mo in those without) (p=0.034)).

Conclusion

These data show that baseline GLS% is an independent predictor of survival in AL amyloidosis. GLS% is the first functional marker that is independent of the Mayo staging in predicting outcomes and should be incorporated in prognostic staging for patients with AL amyloidosis. GLS% shows improvement in patients who achieve a complete haematologic response to treatment and improvement in GLS% of 1.5% is associated with improved outcomes. An absolute improvement in GLS% should be considered as a criterion for cardiac response in AL amyloidosis.

Funding Acknowledgement

Type of funding source: None

Long-term integrated safety of patisiran in patients with hereditary transthyretin-mediated amyloidosis with polyneuropathy

Background/Introduction

Hereditary transthyretin-mediated (hATTR) amyloidosis is a progressive, life-threatening disease; the majority of patients develop a mixed phenotype of polyneuropathy and cardiomyopathy. Patisiran halted or reversed polyneuropathy and improved quality of life in the Phase 3 (APOLLO) study. In a prespecified cardiac subpopulation of APOLLO, patisiran also improved cardiac structure and function versus placebo.

Purpose

To describe the long-term comprehensive, integrated safety data from the patisiran clinical development program in patients with hATTR amyloidosis with polyneuropathy.

Methods

Safety data as of October 7, 2019 from the Phase 2 Open-Label Extension (OLE) (NCT01961921), Phase 3 APOLLO (NCT01960348), and ongoing Global OLE (NCT02510261) studies were analysed.

Results

Across the three studies, 224 patients received patisiran for a mean (range) of 43.6 (0.7–71.7) months, with a cumulative 813.9 patient-years of exposure; 105 (46.9%) patients received patisiran for ≥4 years and 35 (15.6%) patients received patisiran for ≥5 years. In this cohort, 149 (66.5%) had medical histories of cardiac disorders per MedDRA System Organ Class (SOC), which may be reflective of a mixed phenotype in some patients. A total of 222 (99.1%) patients experienced at least one adverse event (AE) and 132 (58.9%) patients experienced at least one serious AE. AEs considered to be related to patisiran and occurring in >5% of patients included infusion-related reactions (IRRs) (25.9%) and diarrhoea (6.3%). Cardiac AEs occurring in >5% of patients included atrial fibrillation (10.7%) and cardiac failure (7.6%). Amongst all patients, the exposure-adjusted mortality rate was 4.3 deaths per 100 patient-years.

Conclusions

Patients with hATTR amyloidosis with polyneuropathy in the patisiran clinical development program represent those with the longest treatment with an RNAi therapeutic, including more than 15% of patients receiving patisiran for ≥5 years. Patisiran continues to demonstrate a positive benefit:risk profile in patients with hATTR amyloidosis with polyneuropathy.

Funding Acknowledgement

Type of funding source: Private company. Main funding source(s): Alnylam Pharmaceuticals

High prevalence of albuminuria amongst people who inject drugs: A cross-sectional study

Albuminuria is a key biomarker for cardiovascular disease and chronic kidney disease. Our study aimed to describe the prevalence of albuminuria amongst people who inject drugs in London and to test any potential associations with demographic characteristics, past diagnoses, and drug preparation and administration practices. We carried out a cross-sectional survey amongst people who use drugs in London. The main outcome measure was any albuminuria including both microalbuminuria and macroalbuminuria. Three-hundred and sixteen samples were tested by local laboratory services. Our study initially employed point-of-care testing methods but this resulted in a high number of false positives. Our findings suggest the prevalence of albuminuria amongst PWID is twice that of the general population at 19% (95%CI 15.3–24.0%). Risk factors associated with albuminuria were HIV (aOR 4.11 [95% CI 1.37–12.38]); followed by overuse of acidifier for dissolving brown heroin prior to injection (aOR 2.10 [95% CI 1.04–4.22]). Albuminuria is high amongst people who inject drugs compared to the general population suggesting the presence of increased cardiovascular and renal pathologies. This is the first study to demonstrate an association with acidifier overuse. Dehydration may be common amongst this population and may affect the diagnostic accuracy of point-of-care testing for albuminuria.

Long-term outcome of high-dose melphalan and autologous stem cell transplantation for AL amyloidosis

Light chain (AL) amyloidosis is the result of a clonal plasma cell expansion, in which amyloidogenic monoclonal light chains deposit in various tissues resulting in organ dysfunction and organ failure. The median survival of patients with AL amyloidosis without therapy is 10-14 months. Several phase II studies report haematological and clinical remission in up to 50% of patients after high-dose melphalan and autologous stem cell transplantation. We analysed retrospectively the long-term outcome of 19 patients treated in this way between August/1996 and December/2001. We observed a relatively high treatment-related mortality of 26%, but 12 patients (63%) were high-risk candidates. Eight patients (42%) surviving longer than 100 days achieved haematological remission and long-term survival, whereas 6 (32%) obtained no clear benefit from high-dose therapy. However, 62% of patients survived beyond 2 years and the median survival from transplant was 48 months (range 0-104 months).