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.

Association of Transthyretin Val122Ile Variant With Incident Heart Failure Among Black Individuals

IMPORTANCE

A genetic variant in the TTR gene (rs76992529; Val122Ile), present more commonly in individuals with African ancestry (population frequency: 3%-4%), causes misfolding of the tetrameric transthyretin protein complex that accumulates as extracellular amyloid fibrils and results in hereditary transthyretin amyloidosis.

OBJECTIVE

To estimate the association of the amyloidogenic Val122Ile TTR variant with the risk of heart failure and mortality in a large, geographically diverse cohort of Black individuals.

DESIGN, SETTING, AND PARTICIPANTS

Retrospective population-based cohort study of 7514 self-identified Black individuals living in the US participating in the REGARDS (Reasons for Geographic and Racial Differences in Stroke) study with genetic data available and without heart failure at baseline. The participants were enrolled at the baseline visit (2003-2007). The end of follow-up for the majority of outcomes was on December 31, 2018. All-cause mortality data were available through December 31, 2020.

EXPOSURES

TTR Val122Ile (rs76992529) genotype.

MAIN OUTCOME AND MEASURES

The primary outcome was incident heart failure (first hospitalization for heart failure or death due to heart failure). The secondary outcomes were heart failure mortality, cardiovascular mortality, and all-cause mortality. The multivariable Cox proportional hazards regression analyses were adjusted for genetic ancestry and demographic, clinical, and social factors.

RESULTS

Among 7514 Black participants (median age, 64 years [IQR, 57-70 years]; 61% women), the population frequency of the TTR Val122Ile variant was 3.1% (232 variant carriers and 7282 noncarriers). During a median follow-up of 11.1 years (IQR, 5.9-13.5 years), incident heart failure occurred in 535 individuals (34 variant carriers and 501 noncarriers) and the incidence of heart failure was 15.64 per 1000 person-years among variant carriers vs 7.16 per 1000 person-years among noncarriers (adjusted hazard ratio [HR], 2.43 [95% CI, 1.71-3.46]; P < .001). Deaths due to heart failure occurred in 141 individuals (13 variant carriers and 128 noncarriers) and the incidence of heart failure mortality was 6.11 per 1000 person-years among variant carriers vs 1.85 per 1000 person-years among noncarriers (adjusted HR, 4.19 [95% CI, 2.33-7.54]; P < .001). Deaths due to cardiovascular causes occurred in 793 individuals (34 variant carriers and 759 noncarriers) and the incidence of cardiovascular death was 15.18 per 1000 person-years among variant carriers vs 10.61 per 1000 person-years among noncarriers (adjusted HR, 1.69 [95% CI, 1.19-2.39]; P = .003). Deaths due to any cause occurred in 2715 individuals (100 variant carriers and 2615 noncarriers) and the incidence of all-cause mortality was 41.46 per 1000 person-years among variant carriers vs 33.94 per 1000 person-years among noncarriers (adjusted HR, 1.46 [95% CI, 1.19-1.78]; P < .001). There was no significant interaction between TTR variant carrier status and sex on incident heart failure and the secondary outcomes.

CONCLUSIONS AND RELEVANCE

Among a cohort of Black individuals living in the US, being a carrier of the TTR Val122Ile variant was significantly associated with an increased risk of heart failure.

Beta-Blocker Exposure and Survival in Patients With Transthyretin Amyloid Cardiomyopathy

OBJECTIVE

To investigate a potential association between beta-blocker exposure and survival in patients with transthyretin amyloid cardiomyopathy (ATTR-CM).

METHODS

In this real-world prospective registry of 128 consecutive patients with ATTR-CM recruited in 7 institutions in Galicia (Spain), survival of 65 patients who received beta blockers on registry enrollment was compared with that of 63 untreated controls by means of both unweighted Cox regression and Cox regression with inverse probability of treatment weighting. Tolerance to and adverse effects of beta blockers were recorded. Median study follow-up was 520 days.

RESULTS

Patients with ATTR-CM who received beta blockers showed statistically significant lower all-cause mortality than untreated controls as evaluated by either unweighted Cox regression (hazard ratio, 0.31; 95% CI, 0.12 to 0.79) or Cox regression with inverse probability of treatment weighting (hazard ratio, 0.18; 95% CI, 0.08 to 0.41; P<.001). Several sensitivity analyses confirmed the internal validity of these results. The overall frequency of beta-blocker suspension due to adverse effects was 25% (95% CI, 15.5% to 34.5%).

CONCLUSION

In this real-world, prospective, multi-institutional registry, patients with ATTR-CM who received beta blockers had lower all-cause mortality than untreated controls.

Natural History and Disease Progression of Early Cardiac Amyloidosis Evaluated by Echocardiography

Since the diagnosis of cardiac amyloidosis (CA) is often delayed, echocardiographic findings are frequently indicative of advanced cardiomyopathy. We aimed to describe early echocardiographic features in patients subsequently diagnosed with CA. Preamyloid diagnosis echocardiographic studies were screened for structural and functional parameters and stratified according to the pathogenetic subtype (immunoglobulin light-chain [AL] or amyloid transthyretin [ATTR]). Abnormalities were defined based on published guidelines. Our cohort included 75 CA patients of whom 42 (56%) were diagnosed with AL and 33 (44%) with ATTR. Forty-two patients had an earlier echocardiography exam available for review. Patients presented with increased wall thickness (1.3 [interquartile range {IQR} 1.0, 1.5] cm) ≥3 years before the diagnosis of CA and relative wall thickness was increased (0.47 [IQR 0.41, 0.50]) ≥7 years prediagnosis. One to 3 years before CA diagnosis restrictive left ventricular (LV) filling pattern was present in 19% of patients and LV ejection fraction ≤50% was present in 21% of patients. Right ventricular dysfunction was detected concomitantly with disease diagnosis. The echocardiographic phenotype of ATTR versus AL-CA showed increased relative wall thickness (0.74 [IQR 0.62, 0.92] versus 0.62 [IQR 0.54, 0.76], p = 0.004) and LV mass index (144 [IQR 129, 191] versus 115 [IQR 105, 146] g/m², p = 0.020) and reduced LV ejection fraction (50 [IQR 44, 58] versus (60 [IQR 53, 60]%, p = 0.009) throughout the time course of CA progression, albeit survival time was similar. In conclusion, increased wall thickness and diastolic dysfunction in CA develop over a time course of several years and can be diagnosed in their earlier stages by standard echocardiography.

Pharmacological treatment for familial amyloid polyneuropathy

BACKGROUND

Disease-modifying pharmacological agents for transthyretin (TTR)-related familial amyloid polyneuropathy (FAP) have become available in the last decade, but evidence on their efficacy and safety is limited. This review focuses on disease-modifying pharmacological treatment for TTR-related and other FAPs, encompassing amyloid kinetic stabilisers, amyloid matrix solvents, and amyloid precursor inhibitors.

OBJECTIVES

To assess and compare the efficacy, acceptability, and tolerability of disease-modifying pharmacological agents for familial amyloid polyneuropathies (FAPs).

SEARCH METHODS

On 18 November 2019, we searched the Cochrane Neuromuscular Specialised Register, the Cochrane Central Register of Controlled Trials, MEDLINE, and Embase. We reviewed reference lists of articles and textbooks on peripheral neuropathies. We also contacted experts in the field. We searched clinical trials registries and manufacturers' websites.

SELECTION CRITERIA

We included randomised clinical trials (RCTs) or quasi-RCTs investigating any disease-modifying pharmacological agent in adults with FAPs. Disability due to FAP progression was the primary outcome. Secondary outcomes were severity of peripheral neuropathy, change in modified body mass index (mBMI), quality of life, severity of depression, mortality, and adverse events during the trial.

DATA COLLECTION AND ANALYSIS

We followed standard Cochrane methodology.

MAIN RESULTS

The review included four RCTs involving 655 people with TTR-FAP. The manufacturers of the drugs under investigation funded three of the studies. The trials investigated different drugs versus placebo and we did not conduct a meta-analysis. One RCT compared tafamidis with placebo in early-stage TTR-FAP (128 randomised participants). The trial did not explore our predetermined disability outcome measures. After 18 months, tafamidis might reduce progression of peripheral neuropathy slightly more than placebo (Neuropathy Impairment Score (NIS) in the lower limbs; mean difference (MD) -3.21 points, 95% confidential interval (CI) -5.63 to -0.79; P = 0.009; low-certainty evidence). However, tafamidis might lead to little or no difference in the change of quality of life between groups (Norfolk Quality of Life-Diabetic Neuropathy (Norfolk QOL-DN) total score; MD -4.50 points, 95% CI -11.27 to 2.27; P = 0.19; very low-certainty evidence). No clear between-group difference was found in the numbers of participants who died (risk ratio (RR) 0.65, 95% CI 0.11 to 3.74; P = 0.63; very low-certainty evidence), who dropped out due to adverse events (RR 1.29, 95% CI 0.30 to 5.54; P = 0.73; very low-certainty evidence), or who experienced at least one severe adverse event during the trial (RR 1.16, 95% CI 0.37 to 3.62; P = 0.79; very low-certainty evidence). One RCT compared diflunisal with placebo (130 randomised participants). At month 24, diflunisal might reduce progression of disability (Kumamoto Score; MD -4.90 points, 95% CI -7.89 to -1.91; P = 0.002; low-certainty evidence) and peripheral neuropathy (NIS plus 7 nerve tests; MD -18.10 points, 95% CI -26.03 to -10.17; P < 0.001; low-certainty evidence) more than placebo. After 24 months, changes from baseline in the quality of life measured by the 36-Item Short-Form Health Survey score showed no clear difference between groups for the physical component (MD 6.10 points, 95% CI 2.56 to 9.64; P = 0.001; very low-certainty evidence) and the mental component (MD 4.40 points, 95% CI -0.19 to 8.99; P = 0.063; very low-certainty evidence). There was no clear between-group difference in the number of people who died (RR 0.46, 95% CI 0.15 to 1.41; P = 0.17; very low-certainty evidence), in the number of dropouts due to adverse events (RR 2.06, 95% CI 0.39 to 10.87; P = 0.39; very low-certainty evidence), and in the number of people who experienced at least one severe adverse event (RR 0.77, 95% CI 0.18 to 3.32; P = 0.73; very low-certainty evidence) during the trial. One RCT compared patisiran with placebo (225 randomised participants). After 18 months, patisiran reduced both progression of disability (Rasch-built Overall Disability Scale; least-squares MD 8.90 points, 95% CI 7.00 to 10.80; P < 0.001; moderate-certainty evidence) and peripheral neuropathy (modified NIS plus 7 nerve tests - Alnylam version; least-squares MD -33.99 points, 95% CI -39.86 to -28.13; P < 0.001; moderate-certainty evidence) more than placebo. At month 18, the change in quality of life between groups favoured patisiran (Norfolk QOL-DN total score; least-squares MD -21.10 points, 95% CI -27.20 to -15.00; P < 0.001; low-certainty evidence). There was little or no between-group difference in the number of participants who died (RR 0.61, 95% CI 0.21 to 1.74; P = 0.35; low-certainty evidence), dropped out due to adverse events (RR 0.33, 95% CI 0.13 to 0.82; P = 0.017; low-certainty evidence), or experienced at least one severe adverse event (RR 0.91, 95% CI 0.64 to 1.28; P = 0.58; low-certainty evidence) during the trial. One RCT compared inotersen with placebo (172 randomised participants). The trial did not explore our predetermined disability outcome measures. From baseline to week 66, inotersen reduced progression of peripheral neuropathy more than placebo (modified NIS plus 7 nerve tests - Ionis version; MD -19.73 points, 95% CI -26.50 to -12.96; P < 0.001; moderate-certainty evidence). At week 65, the change in quality of life between groups favoured inotersen (Norfolk QOL-DN total score; MD -10.85 points, 95% CI -17.25 to -4.45; P < 0.001; low-certainty evidence). Inotersen may slightly increase mortality (RR 5.94, 95% CI 0.33 to 105.60; P = 0.22; low-certainty evidence) and occurrence of severe adverse events (RR 1.48, 95% CI 0.85 to 2.57; P = 0.16; low-certainty evidence) compared to placebo. More dropouts due to adverse events were observed in the inotersen than in the placebo group (RR 8.57, 95% CI 1.16 to 63.07; P = 0.035; low-certainty evidence). There were no studies addressing apolipoprotein AI-FAP, gelsolin-FAP, and beta-2-microglobulin-FAP.

AUTHORS' CONCLUSIONS

Evidence on the pharmacological treatment of FAPs from RCTs is limited to TTR-FAP. No studies directly compare disease-modifying pharmacological treatments for TTR-FAP. Results from placebo-controlled trials indicate that tafamidis, diflunisal, patisiran, and inotersen may be beneficial in TTR-FAP, but further investigations are needed. Since direct comparative studies for TTR-FAP will be hampered by sample size and costs required to demonstrate superiority of one drug over another, long-term non-randomised open-label studies monitoring their efficacy and safety are needed.

Finnish gelsolin amyloidosis causes significant disease burden but does not affect survival: FIN-GAR phase II study

BACKGROUND

Hereditary gelsolin (AGel) amyloidosis is an autosomal dominantly inherited systemic amyloidosis that manifests with the characteristic triad of progressive ophthalmological, neurological and dermatological signs and symptoms. The National Finnish Gelsolin Amyloidosis Registry (FIN-GAR) was founded in 2013 to collect clinical data on patients with AGel amyloidosis, including altogether approximately one third of the Finnish patients. We aim to deepen knowledge on the disease burden and life span of the patients using data from the updated FIN-GAR registry. We sent an updated questionnaire concerning the symptoms and signs, symptomatic treatments and subjective perception on disease progression to 240 members of the Finnish Amyloidosis Association (SAMY). We analyzed the lifespan of 478 patients using the relative survival (RS) framework.

RESULTS

The updated FIN-GAR registry includes 261 patients. Symptoms and signs corresponding to the classical triad of ophthalmological (dry eyes in 93%; corneal lattice amyloidosis in 89%), neurological (numbness, tingling and other paresthesias in 75%; facial paresis in 67%), and dermatological (drooping eyelids in 86%; cutis laxa in 84%) manifestations were highly prevalent. Cardiac arrhythmias were reported by 15% of the patients and 5% had a cardiac pacemaker installed. Proteinuria was reported by 13% and renal failure by 5% of the patients. A total of 65% of the patients had undergone a skin or soft tissue surgery, 26% carpal tunnel surgery and 24% at least unilateral cataract surgery. As regards life span, relative survival estimates exceeded 1 for males and females until the age group of 70-74 years, for which it was 0.96.

CONCLUSIONS

AGel amyloidosis causes a wide variety of ophthalmological, neurological, cutaneous, and oral symptoms that together with repeated surgeries cause a clinically significant disease burden. Severe renal and cardiac manifestations are rare as compared to other systemic amyloidoses, explaining in part the finding that AGel amyloidosis does not shorten the life span of the patients at least for the first 75 years.

Use of Ventilatory Efficiency Slope as a Marker for Increased Mortality in Wild-Type Transthyretin Cardiac Amyloidosis

Wild-type transthyretin amyloidosis (ATTRwt) results in an infiltrative cardiomyopathy often culminating in symptomatic heart failure. The use of cardiopulmonary exercise testing (CPET) in determining outcomes in ATTRwt cardiac amyloidosis is unknown. Given the emergence of novel therapies to treat transthyretin amyloidosis, we sought to investigate the utility of CPET on outcomes in patients with ATTRwt cardiomyopathy. Fifty-six patients, with biopsy and immunohistochemically proved ATTRwt, were enrolled between 2005 and 2015, as part of an NIH ATTRwt substudy at the Boston University Amyloidosis Center. Patients were prospectively studied, which included laboratory tests, electrocardiogram, echocardiography, in addition to CPET. In this cohort of ATTRwt patients who performed CPET were elderly, all were male, and predominantly white (69.9%). The overall median survival was 59.01 months (95% confidence interval [CI] 49.29 to 88.69). By multivariate analysis, C-reactive protein (CRP; hazard ratio [HR] 1.10 [1.03 to 1.18]), decreased sodium (HR 0.75 [0.58 to 0.97]), creatinine (HR 7.48 [2.44 to 22.98]) and VE/VCO₂ (HR 1.10 [1.05 to 1.16]) were significant risk factors for mortality (p <0.05). Peak VO₂ was insignificant by both univariate and multivariate analyses. ATTRwt patients with VE/VCO₂ >40 had a worse median survival of 38.54 months (95% CI 32.63 to 51.47) versus 88.69 months (95% CI 56.26 to 89.49) than patients with VE/VCO₂ slope ≤40. Receiver-operating characteristic curve showed that the combination of VE/VCO_2, CRP, sodium, and creatinine (Area under the ROC Curve [AUC], 0.89) predicted 1-year mortality in ATTRwt cardiac amyloidosis. In conclusion, increased VE/VCO₂, in combination with CRP, sodium, and creatinine, may identify patients at increased risk of death in ATTRwt cardiomyopathy. VE/VCO₂ might have a role in objectively assessing therapeutic response in ATTRwt cardiac amyloidosis.

Non-parametric estimation of survival in age-dependent genetic disease and application to the transthyretin-related hereditary amyloidosis

In genetic diseases with variable age of onset, survival function estimation for the mutation carriers as well as estimation of the modifying factors effects are essential to provide individual risk assessment, both for mutation carriers management and prevention strategies. In practice, this survival function is classically estimated from pedigrees data where most genotypes are unobserved. In this article, we present a unifying Expectation-Maximization (EM) framework combining probabilistic computations in Bayesian networks with standard statistical survival procedures in order to provide mutation carrier survival estimates. The proposed approach allows to obtain previously published parametric estimates (e.g. Weibull survival) as particular cases as well as more general Kaplan-Meier non-parametric estimates, which is the main contribution. Note that covariates can also be taken into account using a proportional hazard model. The whole methodology is both validated on simulated data and applied to family samples with transthyretin-related hereditary amyloidosis (a rare autosomal dominant disease with highly variable age of onset), showing very promising results.

Technetium pyrophosphate uptake in transthyretin cardiac amyloidosis: Associations with echocardiographic disease severity and outcomes

BACKGROUND

Quantitative uptake of Technetium 99 m-pyrophosphate (TcPYP) is sensitive and specific for diagnosing transthyretin cardiac amyloidosis (ATTR). We sought to examine the association between TcPYP uptake intensity and echocardiographic measures of disease severity and clinical outcomes.

METHODS AND RESULTS

A retrospective analysis was performed of 75 patients who underwent TcPYP scintigraphy. Planar images were evaluated semiquantitatively and using heart-to-contralateral lung (H/CL) ratio. The associations between H/CL ratio and echocardiographic parameters and outcomes were evaluated using linear regression and Cox models, respectively. There were 48 patients diagnosed with ATTR with mean H/CL ratio 1.58 ± 0.22 (vs 1.08 ± 0.09 if semiquantitative score = 0). The H/CL ratio was not associated with any measured echocardiographic parameter. Both semiquantitative uptake grade and H/CL ratio were associated with all-cause mortality (P = 0.009 and 0.007, respectively) and all-cause mortality or heart failure hospitalization (P = 0.001 and 0.020, respectively); however, neither were associated with outcomes when limited to patients with confirmed ATTR (P = 0.18 and 0.465, respectively).

CONCLUSION

In patients with suspected ATTR, quantitative and semiquantitative uptake intensity of TcPYP is associated with all-cause mortality as well as all-cause mortality or heart failure hospitalization. However, in those with confirmed ATTR, there is no association with echocardiographic disease severity or outcomes.

Natural History of Wild-Type Transthyretin Cardiac Amyloidosis and Risk Stratification Using a Novel Staging System

BACKGROUND

Wild-type transthyretin cardiac amyloidosis (ATTRwt) is increasingly recognized as an important cause of heart failure.

OBJECTIVES

The purpose of this study was to determine the natural history of ATTRwt and the predictors of survival.

METHODS

We retrospectively reviewed patients diagnosed with ATTRwt at the Mayo Clinic through 2013 and recorded clinical data and survival data. Factors affecting overall survival (OS) were identified, and a prognostic staging system was developed.

RESULTS

The median age of the 360 patients diagnosed before death was 75 years (range: 47 to 94 years), and 91% were male. Presenting signs and symptoms included dyspnea or heart failure in 67% and atrial arrhythmias in 62%. Median OS from diagnosis was 3.6 years and did not change over time. Multivariate predictors of mortality included age, ejection fraction, pericardial effusion, N-terminal pro-B-type natriuretic peptide, and troponin T. A staging system was developed that used thresholds of troponin T (0.05 ng/ml) and N-terminal pro-B-type natriuretic peptide (3,000 pg/ml). The respective 4-year OS estimates were 57%, 42%, and 18% for stage I (both values below cutoff), stage II (one above), and stage III (both above), respectively. Stage III patients were at an increased risk of mortality after adjustment for age and sex compared with stage I patients (hazard ratio: 3.6; p < 0.001).

CONCLUSIONS

The natural history of ATTRwt is poor. We report a novel cardiac biomarker staging system that enables risk stratification in an era of emerging treatment strategies.

Cardiac Dysautonomia Predicts Long-Term Survival in Hereditary Transthyretin Amyloidosis After Liver Transplantation

OBJECTIVES

This study sought to compare techniques evaluating cardiac dysautonomia and predicting the risk of death of patients with hereditary transthyretin amyloidosis (mATTR) after liver transplantation (LT).

BACKGROUND

mATTR is a multisystemic disease involving mainly the heart and the peripheral nervous system. LT is the reference treatment, and pre-operative detection of high-risk patients is critical. Cardiovascular dysautonomia is commonly encountered in ATTR and may affect patient outcome, although it is not known yet which technique should be used in the field to evaluate it.

METHODS

In a series of 215 consecutive mATTR patients who underwent LT, cardiac dysautonomia was assessed by a dedicated clinical score, time-domain heart rate variability, ¹²³-meta-iodobenzylguanidine heart/mediastinum (¹²³-MIBG H/M) ratio on scintigraphy, and heart rate response to atropine (HRRA).

RESULTS

Patient median age was 43 years, 62% were male and 69% carried the Val30Met mutation. Cardiac dysautonomia was documented by at least 1 technique for all patients but 6 (97%). In univariate analysis, clinical score, ¹²³-MIBG H/M ratio and HRRA were associated with mortality but not heart rate variability. The ¹²³-MIBG H/M ratio and HRRA had greater area under the curve (AUC) of receiver-operating characteristic curves than clinical score and heart rate variability (AUC: 0.787, 0.748, 0.656, and 0.523, respectively). Multivariate score models were then built using the following variables: New York Heart Association functional class, interventricular septum thickness, and either ^123-MIBG H/M ratio (S_MIBG) or HRRA (S_atropine). AUC of S_MIBG and S_atropine were greater than AUC of univariate models, although nonsignificantly (AUC: 0.798 and 0.799, respectively). Predictive powers of S_MIBG, S_atropine, and a reference clinical model (AUC: 0.785) were similar.

CONCLUSIONS

Evaluation of cardiac dysautonomia is a valuable addition for predicting survival of mATTR patients following LT. Among the different techniques that evaluate cardiac dysautonomia, ¹²³-MIBG scintigraphy and heart rate response to atropine had better prognostic accuracy. Multivariate models did not improve significantly prediction of outcome.

Clinical features and outcomes of systemic amyloidosis with gastrointestinal involvement: a single-center experience

BACKGROUND/AIMS

The gastrointestinal (GI) tract often becomes involved in patients with systemic amyloidosis. As few GI amyloidosis data have been reported, we describe the clinical features and outcomes of patients with pathologically proven GI amyloidosis.

METHODS

We identified 155 patients diagnosed with systemic amyloidosis between April 1995 and April 2013. Twenty-four patients (15.5%) were diagnosed with GI amyloidosis using associated symptoms, and the diagnoses were confirmed by direct biopsy.

RESULTS

Among the 24 patients, 20 (83.3%) had amyloidosis light chain (AL), three (12.5%) had amyloid A, and one (4.2%) had transthyretin-related type amyloidosis. Their median age was 57 years (range, 37 to 72), and 10 patients were female (41.7%). The most common symptoms of GI amyloidosis were diarrhea (11 patients, 45.8%), followed by anorexia (nine patients, 37.5%), weight loss, and nausea and/or vomiting (seven patients, 29.2%). The histologically confirmed GI tract site in AL amyloidosis was the stomach in 11 patients (55.0%), the colon in nine (45.0%), the rectum in seven (35.0%), and the small bowel in one (5.0%). Patients with GI involvement had a greater frequency of organ involvement (p = 0.014). Median overall survival (OS) in patients with GI involvement was shorter (7.95 months; range, 0.3 to 40.54) than in those without GI involvement (15.84 months; range, 0.0 to 114.53; p = 0.069) in a univariate analysis. A multivariate analysis of prognostic factors for AL amyloidosis revealed that GI involvement was not a significant predictor of OS (p = 0.447).

CONCLUSIONS

The prognosis of patients with AL amyloidosis and GI involvement was poorer than those without GI involvement, and they presented with more organ involvement and more advanced disease than those without organ involvement.

Reduced myocardial 123-iodine metaiodobenzylguanidine uptake: a prognostic marker in familial amyloid polyneuropathy

BACKGROUND

Transthyretin familial amyloid polyneuropathy is a hereditary form of amyloidosis characterized by sensorimotor and autonomic neuropathy, cardiac conduction defects, and infiltrative cardiomyopathy. Previous studies have suggested that myocardial sympathetic denervation assessed by 123-iodine metaiodobenzylguanidine (MIBG) imaging occurs early in disease progression. However, its prognostic significance was never evaluated. We aimed to study the long-term prognostic value of myocardial sympathetic denervation detected by MIBG imaging in transthyretin familial amyloid polyneuropathy.

METHODS AND RESULTS

A total of 143 individuals with V30M transthyretin mutation underwent Holter, ambulatory blood pressure monitoring, echocardiography, and MIBG imaging. Time to all-cause death was compared with late heart-to-mediastinum MIBG uptake ratio (H/M; either in relation to the estimated lower limit of normal [1.60] or as a continuous variable) using Cox proportional hazards regression. Multivariable analyses were performed to test the prognostic accuracy of clinical, neurological, and cardiovascular parameters. During a median follow-up of 5.5 years, 32 (22%) patients died. Five-year mortality rate was 42% for late H/M <1.60 and 7% for late H/M ≥1.60 (hazard ratio, 7.19; P<0.001). Late H/M was identified as an independent prognostic predictor. Fifty-three patients were submitted to liver transplantation. In comparison with neurophysiological score-matched controls, transplanted patients had lower long-term mortality (hazard ratio, 0.32; P=0.012). Patients with late H/M<1.60 were at higher risk of unfavorable outcome but seemed to have benefited from liver transplantation.

CONCLUSIONS

Cardiac sympathetic denervation as assessed by MIBG imaging is a useful prognostic marker in transthyretin familial amyloid polyneuropathy.

Long-term consequences of domino liver transplantation using familial amyloidotic polyneuropathy grafts

Domino liver transplantation (DLT) using grafts from patients with familial amyloidotic polyneuropathy (FAP) is an established procedure at many transplantation centers. However, data evaluating the long-term outcome of DLT are limited. The aim of the present study was to analyze the risk of de novo polyneuropathy, possibly because of amyloidosis, and the patient survival after DLT. At our department, 28 DLT using FAP grafts were conducted between January 1997 and December 2005. One patient was twice subjected to DLT. Postoperative neurological monitoring of peripheral nerve function was performed with electroneurography (ENeG) in 20 cases. An ENeG index based on 12 parameters was calculated and correlated to age and/or height. Three patients developed ENeG signs of polyneuropathy 2-5 years after the DLT, but with no clinical symptoms. The 1-, 3- and 5-year actuarial patient survival in hepatocellular carcinoma (HCC) patients (n = 12) and non-HCC patients (n = 15) was 67%, 15%, 15% and 93%, 93%, 80%, respectively (P = 0.001). Development of impaired nerve conduction in a proportion of patients may indicate that de novo amyloidosis occurs earlier than previously expected. Survival after DLT was excellent except in patients with advanced HCC.

[Late-onset familial amyloid polyneuropathy in the Safor (Valencia) area: four case reports]

Four cases of late onset familial amyloid polyneuropathy diagnosed in relatively advanced ages and within 3 families of our area where the disease had never been described are presented. The possible origin of the mutation and need to consider this diagnosis even when there is no known family background or when the age of presentation is late are commented. The nerve biopsy does not always show the deposits as these are patchy and DNA studies or detection of abnormal TTR in serum are necessary for the diagnosis.

Early liver transplantation improves familial amyloidotic polyneuropathy patients' survival

Since the first liver transplantation for familial amyloidotic polyneuropathy was performed in 1990, it has become an accepted treatment for this systemic amyloid disorder. Liver transplantation halts the production of the mutated amyloidogenic transthyretin, and thereby amyloid formation, and also progression of the majority of symptoms. Improvement in survival from onset of disease in transplanted patients compared to non-transplanted subjects has of yet not been demonstrated, partly because of the natural relatively slow progression of the disease with an expected median survival of 13 years. In this retrospective study we compared the early initial series (n=34) of transplantations, where severely malnourished patients were accepted, with a later series (n=27) of transplants, as well as a control group (n=19) consisting of non-transplanted patients. For transplanted patients with an modified body mass index (mBMI) above 600 an improved survival was noted compared with that of non-transplanted historical controls. So far no difference in survival between the early and late series has been found. Our previous recommendation of selection of patients primarily according to their nutritional status appears to be well justified, since it is now possible to demonstrate an increased survival for the transplanted group of patients with a preserved nutritional status (mBMI > 600) compared to the control group of non-transplanted patients.

Ten years of experience with liver transplantation for familial amyloid polyneuropathy in Japan: outcomes of living donor liver transplantations

OBJECTIVE

We summarize 10 years of experience with liver transplantation for FAP patients in Japan and review the current opinions regarding this treatment for FAP.

METHODS AND PATIENTS

All basic report data on patients at the time of transplantation were registered with the Japanese Liver Transplantation Society (JLTS). Based on the JLST report data, more detailed information on FAP patients was requested from each center.

RESULTS

Living donor liver transplantation (LDLT) for FAP patients was first performed in Japan in 1993. LDLT has since been performed in 41 FAP patients, including nine cases of temporary auxiliary partial orthotopic liver transplantation (APOLT). Orthotopic liver transplantation (OLT) from cadaveric donors for FAP patients began in 1999, but only one FAP patient has subsequently undergone this procedure. Of these total of 43 FAP patients, 36 are currently alive: the one-year survival rate of patients after transplantation was 93%, and the five-year survival rate of these cases was 77%. Preoperative clinical severity and the nutritional status of patients are correlated with their outcome after liver transplantation. Domino (sequential) liver transplantation has been carried out in 20 domino recipients with end-stage liver diseases. Of the 20 domino recipients, 12 are currently alive.

CONCLUSION

For FAP patients, these outcomes after the operation were very similar to those of OLT from cadaveric donors reported in other countries. Therefore, we concluded that for the treatment of FAP, LDLT from a living donor is equally effective as OLT from a cadaveric donor.

Genetic epidemiology of familial amyloid polyneuropathy in the Balearic Islands (Spain)

Between 1976 and 2003, we diagnosed 144 patients with familial amyloid polyneuropathy (FAP) in the Balearic Islands (Spain). Analysis of genetic epidemiological data from 102 confirmed patients showed 62% were men. Parental transmission was paternal in 38, maternal in 25, and unknown in 39. No family history of FAP was found in 32 patients. TTRVal30Met associated with haplotype I was present in the individuals studied. Mean age-at-onset was 45.7 years which lies between that of Sweden and those of Portugal, Japan and Brazil. Duration of FAP was of 9.7 years. Age-at-onset, age-at-death, duration and fertility were similar between sexes. Twenty-nine intergeneration familial pairs of patients were ascertained. Raw anticipation was positive in twenty-four pairs, zero in one, and negative in four. Differences greater than 9 years between age-at-onset of the first and second member were considered relevant; positive relevant anticipation was found in 76% of the whole pairs. The frequency of positive anticipation of parent-child pairs was not significantly different than those described in the Swedish and Portuguese series. Significant positive correlation in age-at-onset was confirmed in twenty-seven types of pairs supporting the hypothesis that a genetic factor may modulate age-at-onset. The Balearic focus of FAP is expanding and constitutes a public health problem.

Outcome of exercise electrocardiography in familial amyloidotic polyneuropathy patients, Portuguese type, under evaluation for liver transplantation

Familial amyloidotic polyneuropathy (FAP) is a dominantly inherited systemic amyloidosis caused by mutated transthyretin (TTR). Liver transplantation is currently the only available treatment that halts the progress of the disease. Cardiovascular complications are common in FAP, and cardiac arrhythmias are typical complications in FAP Val30Met. For patients with late onset FAP, as the Swedish patients, coronary heart disease has been found in several patients, and a QS complex is not an uncommon finding in FAP-patients ECG raising the suspicion of coronary heart disease. The aim of this study was to evaluate exercise ECG in FAP patients before transplantation with regard to mortality and morbidity. Thirty-eight FAP patients who underwent examination by exercise ECG, as part of the evaluation for liver transplantation were included in the study. Of these, 30 patients were transplanted, and the surviving patients were followed for at least 2 years. Exercise ECG was performed on bicycles with standard 12 leads. Non-parametric statistical analyses were used in all calculations. Six patients died 0-5.5 years after transplantation. They were older than the survivors (p < 0.01), but their duration of disease did not deviate from that of survivors (p = 0.8). They were also less able to increase their heart rates during exercise than the survivors (p < 0.05). For all transplanted patients, a significant relationship was found between patients' increase of heart rate, blood pressure and maximal workload, and the duration of disease and also for the PND-score, signifying that the outcome of exercise ECG predominantly was related to the patients autonomic and motor function, and not to their heart function.

End-stage renal disease and dialysis in hereditary amyloidosis TTR V30M: presentation, survival and prognostic factors

Classical familial amyloid polyneuropathy may have a course with progressive renal impairment. We studied 62 patients (24 males, 38 females) with FAP, transthyretin variant V30M, and end-stage renal disease (ESRD) treated with hemodialysis, all referred to a single center over a period of 11 years. Clinical course, morbidity and survival after dialysis were analyzed. Patient's mean age at first dialysis was 51.5 +/- 10.7 years, and mean duration of neuropathy was 10.2 +/- 3.8 years. The most frequent form of presentation of FAP nephropathy was nephrotic proteinuria with renal dysfunction. In the year prior to dialysis, renal function declined rapidly, and fluid overload was the main indication to initiate treatment. The presence of decubitus ulcers, significant disability, venous catheter for definitive vascular access for long-term treatment, and permanent bladder catheter, were related to death during the first year of dialysis. The mean duration of renal replacement therapy was 21 months, with a 54.5% one year, and 38.4% two year treatment survival. However, when the duration of neurological symptoms at first dialysis exceeded 10 years, survival was significantly lower. Infections, (41% were decubitus ulcers with sepsis) were the cause of early, as well as late mortality. Early creation of vascular access for hemodialysis, surveillance of skin wounds, and intervention on neurogenic bladder are essential to improve the prognosis of ESRD in FAP.

Ten years of international experience with liver transplantation for familial amyloidotic polyneuropathy: results from the familial amyloidotic polyneuropathy world transplant registry

BACKGROUND

Transthyretin (TTR) amyloidosis is a group of systemic amyloidoses disorders caused by an amyloidogenic TTR variant. Untreated, it slowly leads to severely disabling symptoms that relentlessly progress until the death of the patient. Because the mutant form of TTR is produced mainly in the liver, successful orthotopic liver transplantation (OLT) results in the elimination of the source of the variant TTR molecule and is presently the only known curative treatment. OLT in patients with familial amyloidotic polyneuropathy (FAP) was first performed in 1990 at the Karolinska Institute in Sweden, and because the results were promising other centers took up the procedure.

METHODS

To gain as great an experience as possible regarding this treatment, the Familial Amyloidotic Polyneuropathy World Transplant Registry (FAPWTR) was initiated in 1995, and this article presents the 10-year registry results.

RESULTS

A total of 54 centers in 16 countries have performed OLT for FAP, and today approximately 60 OLTs are performed annually worldwide. During the last decade, a total of 539 patients have undergone 579 OLTs. Patient survival is excellent (overall 5-year patient survival 77%) and comparable to the survival with OLT performed for other chronic liver disorders, but longer follow-up is needed to compare the outcome after OLT with the natural course of the disease. The main cause of death was cardiac related (39%).

CONCLUSIONS

We believe that the FAPWTR has become a valuable tool that will help to accurately evaluate the potential risks and benefits of OLT in patients with FAP and promote a fruitful collaboration between centers engaged in this field.

Outcome of liver transplantation for familial amyloidotic polyneuropathy

Familial amyloidotic polyneuropathy (FAP) is an autosomal dominant disorder caused by mutation in the transthyretin gene. The most common mutation is substitution of valine for methionine at position 30 (MET30). Liver transplantation (LT) is the preferred treatment. After LT, although many patients show stabilization or improvement in the disease, adverse outcomes have been reported in those who have malnutrition, long-standing disease, and non-MET (NMET) mutations at position 30. Our aim is to compare survival and outcome of symptoms associated with FAP after LT in patients with MET30 and NMET30 mutations. Medical records of all patients who underwent LT for amyloidosis at our institution were reviewed to obtain demographic information and clinical features, such as severity of neuropathy, diarrhea, orthostatic hypotension, and posterior wall or ventricle septal thickness before and after LT. Fifteen patients underwent LT for amyloidosis at our institution between 1990 and 2000 (MET30, n = 5; NMET30, n = 7; hereditary amyloidosis, n = 2; primary amyloidosis, AL type, n = 1). Patients with hereditary and primary amyloidosis were excluded from analysis. One- and 3-year survival rates after LT in MET30 patients were 100%. Before LT, five of five patients had sensorimotor neuropathy; five of five patients had diarrhea, and four of five patients had orthostatic hypotension. After LT, improvement or stabilization of neuropathy was seen in two of five patients; of diarrheal symptoms, in three of five patients; and of orthostatic hypotension, in three of four patients. One- and 3-year survival rates after LT in NMET30 patients were 100% and 85.7%, respectively. Before LT, six of seven patients had sensorimotor neuropathy, six of seven patients had diarrhea, and five of seven patients had orthostatic hypotension. After LT in this group, improvement or stabilization of neuropathy was seen in two of six patients; of diarrhea, in six of six patients; and of orthostatic hypotension, in five of five patients. Before LT, posterior wall and/or ventricle septal thickness was increased in two of five MET patients and seven of seven NMET patients. Five of seven NMET30 patients (71.4%) who received a combined liver and heart transplant had stabilization, and two patients in the NMET group and one patient in the MET group had progression of heart disease. Outcomes for LT for patients with FAP with MET or NMET mutations were similar. Earlier LT for patients with FAP with MET30 or NMET30 mutation would improve outcomes after LT.