Left Ventricular Hypertrophy and Late Gadolinium Enhancement at Cardiac MRI Are Associated with Adverse Cardiac Events in Fabry Disease

Clinical staging of Anderson-Fabry cardiomyopathy: An operative proposal

As a slowly progressive form of hypertrophic cardiomyopathy (HCM), Anderson-Fabry disease (FD) resembles the phenotype of the most common sarcomeric forms, although significant differences in presentation and long-term progression may help determine the correct diagnosis. A variety of electrocardiographic and imaging features of FD cardiomyopathy have been described at different times in the course of the disease, and considerable discrepancies remain regarding the assessment of disease severity by individual physicians. Therefore, we here propose a practical staging of FD cardiomyopathy, in hopes it may represent the standard for cardiac evaluation and facilitate communication between specialized FD centres and primary care physicians. We identified 4 main stages of FD cardiomyopathy of increasing severity, based on available evidence from clinical and imaging studies: non-hypertrophic, hypertrophic - pre-fibrotic, hypertrophic - fibrotic, and overt dysfunction. Each stage is described and discussed in detail, following the principle that speaking a common language is critical when managing such complex patients in a multi-disciplinary and sometimes multi-centre setting.

Cardiac MRI and Clinical Outcomes in TMEM43 Arrhythmogenic Cardiomyopathy

Arrhythmogenic cardiomyopathy is an inherited cardiomyopathy that can involve both ventricles. Several genes have been identified as pathogenic in arrhythmogenic cardiomyopathy, including TMEM43. However, there are limited data on cardiac MRI findings in patients with TMEM43 variants to date. In this case series, cardiac MRI findings and clinical outcomes are described in 14 patients with TMEM43 variants, including eight (57%) with the pathogenic p.Ser358Leu variant (six female patients; mean age, 33 years ± 15 [SD]) and six (43%) with a TMEM43 variant of unknown significance (three female patients; mean age, 38 years ± 11). MRI findings demonstrated left ventricular systolic dysfunction in eight (57%) patients and right ventricular dysfunction in four (29%) patients. Among the nine patients with late gadolinium enhancement imaging, left ventricular late gadolinium enhancement was present in seven (78%; all subepicardial) patients. In summary, TMEM43 variants are associated with high prevalence of subepicardial late gadolinium enhancement and left ventricular dysfunction. Keywords: Arrhythmogenic Cardiomyopathy, Arrhythmogenic Right Ventricular Cardiomyopathy, TMEM43, Cardiac MRI, Genetic Variants Supplemental material is available for this article.

Fabry Disease: More than a Phenocopy of Hypertrophic Cardiomyopathy

Fabry disease (FD) is a genetic lysosomal storage disease with frequent cardiovascular involvement, whose presence is a major determinant of adverse clinical outcomes. As a potentially treatable cause of left ventricular hypertrophy (LVH) and heart failure with preserved ejection fraction, the early recognition of FD is crucial to initiate enzyme replacement therapy and improve long-term prognosis. Multimodality imaging plays a central role in the evaluation of patients with FD and helps in the differential diagnosis of other conditions presenting with LVH. In the present review, we explore the current applications of multimodality cardiac imaging, in particular echocardiography and cardiovascular magnetic resonance, in the diagnosis, prognostic assessment, and follow-up of patients with FD.

Impact of enzyme replacement therapy and migalastat on left atrial strain and cardiomyopathy in patients with Fabry disease

Aims

Cardiomyopathy in Fabry disease (FD) is a major determinant of morbidity and mortality. This study investigates the effects of FD-specific treatment using enzyme replacement therapy (ERT) and chaperone therapy on left atrial (LA) function using two-dimensional speckle tracking echocardiography (2DSTE).

Methods and results

In this prospective observational single-center study, 20 FD patients [10 (50%) females] treated with migalastat, 48 FD patients [24 (50%) females] treated with ERT (agalsidase-alfa and agalsidase-beta), and 30 untreated FD patients (all females) as controls were analyzed. The mean follow-up time ranged from 26 to 81 months. 2DSTE was performed for left ventricle strain, right ventricle strain, and LA strain (LAS). FD-specific treated patients presented with increased left ventricular mass index (LVMi) and higher frequency of left ventricular hypertrophy at baseline, whereas untreated control patients showed normal baseline values. FD-specific treated (including migalastat and ERT) patients showed stabilization of LAS over time (p > 0.05). LVMi was also stable in treated FD patients during observation (p > 0.05).

Conclusion

In patients with FD, treated with either ERT or chaperone therapy, LAS values measured by echocardiographic speckle tracking were stable over time, pointing toward disease stabilization.

State-of-the-Art Imaging of Infiltrative Cardiomyopathies: A Scientific Statement From the American Heart Association

Infiltrative cardiomyopathies comprise a broad spectrum of inherited or acquired conditions caused by deposition of abnormal substances within the myocardium. Increased wall thickness, inflammation, microvascular dysfunction, and fibrosis are the common pathological processes that lead to abnormal myocardial filling, chamber dilation, and disruption of conduction system. Advanced disease presents as heart failure and cardiac arrhythmias conferring poor prognosis. Infiltrative cardiomyopathies are often diagnosed late or misclassified as other more common conditions, such as hypertrophic cardiomyopathy, hypertensive heart disease, ischemic or other forms of nonischemic cardiomyopathies. Accurate diagnosis is also critical because clinical features, testing methodologies, and approach to treatment vary significantly even within the different types of infiltrative cardiomyopathies on the basis of the type of substance deposited. Substantial advances in noninvasive cardiac imaging have enabled accurate and early diagnosis. thereby eliminating the need for endomyocardial biopsy in most cases. This scientific statement discusses the role of contemporary multimodality imaging of infiltrative cardiomyopathies, including echocardiography, nuclear and cardiac magnetic resonance imaging in the diagnosis, prognostication, and assessment of response to treatment.

Targeted literature review exploring the predictive value of estimated glomerular filtration rate and left ventricular mass index as indicators of clinical events in Fabry disease

BACKGROUND

Fabry disease is a rare, progressive X-linked lysosomal storage disorder. It is caused by mutations in the GLA gene resulting in deficiency of α-galactosidase A (α-Gal A), leading to peripheral neuropathy, cardiovascular disease, stroke, end-stage renal disease, gastrointestinal disorders and premature death. Given the long-term nature of disease progression, trials in Fabry disease are often not powered to capture these clinical events. Clinical measures such as estimated glomerular filtration rate (eGFR) and left ventricular mass index (LVMI) are often captured instead. eGFR and LVMI are believed to be associated with long-term Fabry disease clinical events of interest, but the precise relationships are unclear.

OBJECTIVE

We aimed to identify published literature exploring the link between eGFR/LVMI and long-term clinical events in Fabry disease.

METHODS

A comprehensive literature search was conducted in Embase® and MEDLINE® (using Embase.com), and a targeted literature review was conducted. Studies reporting a quantitative relationship between eGFR and/or LVMI and clinical events in Fabry disease were extracted, and narrative synthesis was conducted to understand these predictive relationships.

RESULTS

Eight studies, consisting of seven patient-level retrospective analyses plus one prospective cohort study, met the inclusion criteria. Seven of these studies reported eGFR and six reported LVMI, with five reporting both. All studies presented results for either a composite measure including a range of key Fabry disease clinical events, or a composite outcome that included at least one key Fabry disease clinical event. All studies employed Cox proportional hazards survival modelling. The studies consistently reported that eGFR and LVMI are predictors of key clinical events in Fabry disease, with the findings remaining consistent regardless of the therapy received by patients in the studies.

CONCLUSIONS

The evidence identified suggests that eGFR and LVMI outcomes may be appropriate indicators for long-term clinical events in Fabry disease, and all identified papers implied the same directional relationship. However, additional research is needed to further understand the specific details of these relationships and to quantify them.

Prognostic Implications of the Extent of Cardiac Damage in Patients With Fabry Disease

BACKGROUND

There is limited evidence on the risk stratification of cardiovascular outcomes in patients with Fabry disease (FD).

OBJECTIVES

This study sought to classify FD patients into disease stages, based on the extent of the cardiac damage evaluated by echocardiography, and to assess their prognostic impact in a multicenter cohort.

METHODS

Patients with FD from 5 Italian referral centers were categorized into 4 stages: stage 0, no cardiac involvement; stage 1, left ventricular (LV) hypertrophy (LV maximal wall thickness >12 mm); stage 2, left atrium (LA) enlargement (LA volume index >34 mL/m2); stage 3, ventricular impairment (LV ejection fraction <50% or E/e' ≥15 or TAPSE <17 mm). The study endpoint was the composite of all-cause death, hospitalization for heart failure, new-onset atrial fibrillation, major bradyarrhythmias or tachyarrhythmias, and ischemic stroke.

RESULTS

A total of 314 patients were included. Among them, 174 (56%) were classified as stage 0, 41 (13%) as stage 1, 57 (18%) as stage 2 and 42 (13%) as stage 3. A progressive increase in the composite event rate at 8 years was observed with worsening stages of cardiac damage (log-rank P < 0.001). On multivariable Cox regression analysis, the staging was independently associated with the risk of cardiovascular events (HR: 2.086 per 1-stage increase; 95% CI: 1.487-2.927; P < 0.001). Notably, cardiac staging demonstrated a stronger and additive prognostic value, as compared with the degree of LV hypertrophy.

CONCLUSIONS

In FD patients, a novel staging classification of cardiac damage, evaluated by echocardiography, is strongly associated with cardiovascular outcomes and may be helpful to refine risk stratification.

Detection of sympathetic denervation defects in Fabry disease by hybrid [11C]meta-hydroxyephedrine positron emission tomography and cardiac magnetic resonance

BACKGROUND

Myocardial glycosphingolipid accumulation in patients with Fabry disease (FD) causes biochemical and structural changes. This study aimed to investigate sympathetic innervation in FD using hybrid cardiac positron emission tomography (PET)/magnetic resonance imaging (MRI).

METHODS AND RESULTS

Patients with different stages of Fabry disease were prospectively enrolled to undergo routine CMR at 1.5T, followed by 3T hybrid cardiac PET/MRI with [11C]meta-hydroxyephedrine ([11C]mHED). Fourteen patients with either no evidence of cardiac involvement (n = 5), evidence of left ventricular hypertrophy (LVH) (n = 3), or evidence of LVH and fibrosis via late gadolinium enhancement (LGE) (n = 6) were analyzed. Compared to patients without LVH, patients with LVH or LVH and LGE had lower median T1 relaxation times (ms) at 1.5 T (1007 vs. 889 vs. 941 ms, p = 0.003) and 3T (1290 vs. 1172 vs. 1184 p = .014). Myocardial denervation ([11C]mHED retention < 7%·min) was prevalent only in patients with fibrosis, where a total of 16 denervated segments was found in two patients. The respective area of denervation exceeded the area of LGE in both patients (24% vs. 36% and 4% vs. 32%). However, sympathetic innervation defects ([11C]mHED retention ≤ 9%·min) occurred in all study groups. Furthermore, a reduced sympathetic innervation correlated with an increased left ventricular mass (p = .034, rs = - 0.57) and a reduced global longitudinal strain (GLS) (p = 0.023, rs = - 0.6).

CONCLUSION

Hybrid cardiac PET/MR with [11C]mHED revealed sympathetic innervation defects, accompanied by impaired GLS, in early stages of Fabry disease. However, denervation is only present in patients with advanced stages of FD showing fibrosis on CMR.

Anderson-Fabry disease cardiomyopathy: an update on epidemiology, diagnostic approach, management and monitoring strategies

Anderson-Fabry disease (AFD) is an X-linked lysosomal storage disorder caused by deficient activity of the enzyme alpha-galactosidase. While AFD is recognized as a progressive multi-system disorder, infiltrative cardiomyopathy causing a number of cardiovascular manifestations is recognized as an important complication of this disease. AFD affects both men and women, although the clinical presentation typically varies by sex, with men presenting at a younger age with more neurologic and renal phenotype and women developing a later onset variant with more cardiovascular manifestations. AFD is an important cause of increased myocardial wall thickness, and advances in imaging, in particular cardiac magnetic resonance imaging and T1 mapping techniques, have improved the ability to identify this disease non-invasively. Diagnosis is confirmed by the presence of low alpha-galactosidase activity and identification of a mutation in the GLA gene. Enzyme replacement therapy remains the mainstay of disease modifying therapy, with two formulations currently approved. In addition, newer treatments such as oral chaperone therapy are now available for select patients, with a number of other investigational therapies in development. The availability of these therapies has significantly improved outcomes for AFD patients. Improved survival and the availability of multiple agents has presented new clinical dilemmas regarding disease monitoring and surveillance using clinical, imaging and laboratory biomarkers, in addition to improved approaches to managing cardiovascular risk factors and AFD complications. This review will provide an update on clinical recognition and diagnostic approaches including differentiation from other causes of increased ventricular wall thickness, in addition to modern strategies for management and follow-up.

Cardiac Magnetic Resonance Imaging and Clinical Follow-up in Antimalarial-induced Cardiomyopathy in Patients With Systemic Lupus Erythematosus

Antimalarial-induced cardiomyopathy is under-recognized in clinical practice and there is limited data on the evolution of cardiac imaging abnormalities after cessation of anti-malarial therapy. In this case series of 9 patients with antimalarial-induced cardiomyopathy, follow-up cardiac magnetic resonance imaging demonstrated interval increase in late gadolinium enhancement extent in 89% of patients and interval decrease in left ventricular ejection fraction in all, despite cessation of anti-malarial therapy. Progression of cardiac abnormalities despite cessation of therapy underscores the important role of imaging in the early recognition of antimalarial-related treatment changes.

Cardiac Magnetic Resonance Imaging T1 and T2 Mapping in Systemic Lupus Erythematosus in Relation to Antimalarial Treatment

PURPOSE

Patients with systemic lupus erythematosus (SLE) are at risk of cardiac disease including antimalarial-induced cardiomyopathy (AMIC). The purpose of this study is to evaluate cardiac magnetic resonance imaging parametric mapping findings in SLE patients with AMIC and investigate the relationship of T1/T2 mapping to antimalarial (AM) treatment duration.

MATERIALS AND METHODS

All patients with SLE who had undergone cardiac magnetic resonance imaging with T1/T2 mapping for evaluation of suspected cardiac disease between 2018 and 2021 were evaluated and compared with healthy controls. To facilitate comparison between scanners, T1/T2 values were converted to a z -score using scanner-specific local reference values. Patients were classified into 3 groups: AMIC, myocarditis, and other (no AMIC or myocarditis).

RESULTS

Forty-five SLE patients (47±17 y, 80% female; 8 [18%] with AMIC and 7 [16%] with myocarditis) and 30 healthy controls (39±15 y, 60% female) were included. Patients with AMIC had higher T1 and T2 compared with controls ( z -score 1.1±1.3 vs. 0±0.6, P =0.01 and 1.7±1.1 vs. 0±1.0, P <0.01, respectively) and lower values compared with those with myocarditis (3.7±1.6, P <0.01 and 4.0±2.0, P <0.01, respectively). T1 correlated negatively with AM treatment duration in patients without AMIC or myocarditis ( r =-0.36, P =0.048) and positively in patients with AMIC ( r =0.92, P =0.001). AM treatment duration did not correlate significantly with T1 in patients with myocarditis or with T2 in any group.

CONCLUSIONS

The relationship between T1 and AM treatment duration differed between groups. Native T1 decreases with longer treatment in patients without AMIC or myocarditis, possibility due to glycosphingolipid accumulation. In patients with AMIC, increasing T1 with longer treatment could reflect fibrosis.

Clinical and CMR characteristics associated with cardiac events in patients with Fabry disease

BACKGROUND

The assessment of late gadolinium enhancement (LGE) and left ventricular hypertrophy (LVH) by cardiac magnetic resonance (CMR) as diagnostic and prognostic maker in Fabry disease is advancing. We aimed to investigate the impact of clinical characteristics and CMR findings on cardiac outcome in patients with FD.

METHODS

In this study 55 patients with genetically confirmed FD and available CMR imaging were included. The primary endpoint was defined as a composite of cardiac events including cardiac death, new occurrence of atrial fibrillation, heart failure, ventricular tachycardia and bradycardia requiring device insertion.

RESULTS

During a median follow-up of 4.9 years (IQR 3.7-5.9), 9 patients (16.3%) reached the primary cardiac end point. The global amount of LGE was associated with an increased risk for primary endpoint in the univariate analysis (HR 1.4 per 10% increase in LGE, p = 0.002). However maximal wall thickness (MWT) was the sole independent predictor of the primary endpoint in a stepwise logistic regression model (HR 9.8 per mm increase in MWT, p < 0.0001). Kaplan-Meier analysis revealed significant difference in event free survival rate between patients with and without LVH (Long-rank p = 0.006) and in patients with and without LGE (Long-rank p < 0.001). Patients without LVH and LGE were free of adverse cardiac events.

CONCLUSION

LVH and LGE detected by CMR were associated with adverse cardiac events in FD. In particular maximal wall thickness can be useful in cardiac risk stratification of FD patients.

Treatment of Fabry Disease: Established and Emerging Therapies

Fabry disease (FD) is a rare, X-linked inherited disorder of glycosphingolipid metabolism. It leads to the progressive accumulation of globotriaosylceramide within lysosomes due to a deficiency of α-galactosidase A enzyme. It involves multiple organs, predominantly the renal, cardiac, and cerebrovascular systems. Early diagnosis and treatment are critical to prevent progression to irreversible tissue damage and organ failure, and to halt life-threatening complications that can significantly reduce life expectancy. This review will focus on the established and emerging treatment options for FD.

Cardiac MRI in Fabry disease

Fabry disease is a rare, progressive X-linked inherited disorder of glycosphingolipid metabolism due to a deficiency of α-galactosidase A enzyme. It leads to the accumulation of globotriaosylceramide within lysosomes of multiple organs, predominantly the vascular, renal, cardiac, and nervous systems. Fabry cardiomyopathy is characterized by increased left ventricular wall thickness/mass, functional abnormalities, valvular heart disease, arrhythmias, and heart failure. Early diagnosis and treatment are critical to avoid cardiac or renal complications that can significantly reduce life expectancy in untreated FD. This review will focus on the role of cardiovascular magnetic resonance imaging in the diagnosis, clinical decision-making, and monitoring of treatment efficacy.

Integrating Cardiac MRI Imaging and Multidisciplinary Clinical Care is Associated With Improved Outcomes in Patients With Fabry Disease

Given the inherent complexities of Fabry disease (FD) and evolving landscape of cardiovascular clinical management, there is no established ideal clinical care model for these patients. We identified clinical factors predictive of increased risk of major adverse cardiac events (MACE) in patients with FD targeted to improve clinical outcomes. Ninety-five patients studied over a median follow-up time of 6.3 years, and 26 patients reached the composite endpoint with a high prevalence of heart failure and cerebrovascular events and no cardiac-related mortality. Patients with MACE had worse health-related quality of life scores. Hypertrophy and presence of myocardial fibrosis increase risk of MACE by 4-5 times, and dyslipidemia increases risk of MACE by 3 times. Early Fabry-specific treatment and close monitoring of comorbidities reduce cardiac complications and mortality. These findings highlight the importance of comprehensive multidisciplinary management to help improve outcomes in FD patients.

Left Ventricular Apical Aneurysm in Fabry Disease: Implications for Clinical Significance and Risk Stratification

Background A previously underrecognized phenotype of left ventricular apical aneurysm (LVAA) has been increasingly identified in Fabry disease. This study explored LVAA's clinical prevalence and its prognostic implications over a long-term follow-up. Methods and Results We retrospectively analyzed 268 consecutive patients with Fabry disease at a tertiary medical center. Patients with increased left ventricular mass index were recognized as having left ventricular hypertrophy (LVH). LVAA was identified using either echocardiography or cardiovascular magnetic resonance imaging. Two patients with ischemic LVAA were excluded. The primary end point was a composite of cardiovascular events, including heart failure hospitalization, sustained ventricular tachycardia, ischemic stroke, and all-cause mortality. Of 266 enrolled patients, 105 (39.5%) had LVH (age 58.5±11.9 years, 48.6% men), and 11 (10.5%) had LVAA. Over 49.3±34.8 months of follow-up, 25 patients with LVH experienced composite events, including 9 heart failure hospitalizations, 4 sustained ventricular tachycardia, 6 ischemic strokes, and 15 mortalities. In patients with LVH, those with LVAA had a significantly higher risk of composite events and lower event-free survival than those without LVAA (8 [72.7%] versus 17 [18.1%], log-rank P<0.001). LVAA was independently associated with an increased risk of composite events (hazard ratio, 3.59 [95% CI, 1.30-9.91]; P=0.01) after adjusting for age, sex, advanced heart failure, renal function, dyslipidemia, atrial fibrillation, left ventricular ejection fraction, left ventricular diastolic function, and left ventricular mass index. Conclusions LVAA is present in approximately 10% of patients with Fabry disease and LVH. It is associated with an increased risk of adverse cardiovascular events and may necessitate aggressive treatment.

Validated Model for Prediction of Adverse Cardiac Outcome in Patients With Fabry Disease

BACKGROUND

The cardiac manifestations of Fabry disease are the leading cause of death, but risk stratification remains inadequate. Identifying patients who are at risk of adverse cardiac outcome may facilitate more evidence-based treatment guidance. Contemporary cardiovascular cardiac magnetic resonance biomarkers have become widely adopted, but their prognostic value remains unclear.

OBJECTIVES

The objective of this study was to develop, internally validate, and evaluate the performance of, a prognostic model, including contemporary deep phenotyping, which can be used to generate individual risk estimates for adverse cardiac outcome in patients with Fabry disease.

METHODS

This longitudinal prospective cohort study consisted of 200 consecutive patients with Fabry disease undergoing clinical cardiac magnetic resonance. Median follow-up was 4.5 years (IQR: 2.7-6.3 years). Prognostic models were developed using Cox proportional hazards modeling. Outcome was a composite of adverse cardiac events. Model performance was evaluated. A risk calculator, which provides 5-year estimated risk of adverse cardiac outcome for individual patients, including men and women, was generated.

RESULTS

The highest performing, internally validated, parsimonious multivariable model included age, native myocardial T₁ dispersion (SD of per voxel myocardial T₁ relaxation times), and indexed left ventricular mass. Median optimism-adjusted c-statistic across 5 imputed model development data sets was 0.77 (95% CI: 0.70-0.84). Model calibration was excellent across the full risk profile.

CONCLUSIONS

This study developed and internally validated a risk prediction model that accurately predicts 5-year risk of adverse cardiac outcome for individual patients with Fabry disease, including men and women, which could easily be integrated into clinical care. External validation is warranted.

Multimodality imaging approach to Fabry cardiomyopathy: Any role for nuclear cardiology?

Anderson-Fabry disease (AFD) is a multisystem X-linked disorder of lipid metabolism frequently associated with progressive glycosphingolipid accumulation in cardiac, renal, and nervous cells. The diagnosis of AFD is usually assessed by enzyme assay and genetic tests, but advanced cardiac imaging can be useful in detecting early signs of the disease. Echocardiography and cardiac magnetic resonance are the first-line imaging modalities to investigate cardiac involvement in AFD, but the recent introduction of new molecular and hybrid imaging techniques opens to a wider range of diagnostic applications. This article aims to provide an overview of nuclear cardiology techniques in diagnosis and clinical management of AFD.

Rare Metabolic and Endocrine Diseases with Cardiovascular Involvement: Insights from Cardiovascular Magnetic Resonance - A Review

The identification of rare diseases with cardiovascular involvement poses significant diagnostic challenges due to the rarity of the diseases, but also due to the lack of knowledge and expertise. Most of them remain underrecognized and undiagnosed, leading to clinical mismanagement and affecting the patients' prognosis, as these diseases are per definition life-threatening or chronic debilitating. This article reviews the cardiovascular involvement of the most well-known rare metabolic and endocrine diseases and their diagnostic approach through the lens of cardiovascular magnetic resonance (CMR) imaging and its prognostic role, highlighting its fundamental value compared to other imaging modalities.

Cardiac MRI of Hereditary Cardiomyopathy

Hereditary cardiomyopathy comprises a heterogeneous group of diseases of the cardiac muscle that are characterized by the presence of genetic mutations. Cardiac MRI is central to evaluation of patients with cardiomyopathy owing to its ability to allow evaluation of many different tissue properties in a single examination. For example, cine MRI is the standard of care for assessment of myocardial structure and function. It clearly shows regions of asymmetric wall thickening that are typical of hypertrophic cardiomyopathy and allows it to be differentiated from other hereditary disorders such as Fabry disease or transthyretin cardiac amyloidosis that produce concentric hypertrophy. Late gadolinium enhancement provides a different tissue property and allows these latter two causes of concentric hypertrophy to be distinguished on the basis of their enhancement appearances (Fabry disease shows midwall basal inferolateral enhancement, and amyloidosis shows global subendocardial enhancement). Native T1 mapping may similarly allow differentiation between Fabry disease and amyloidosis without the use of contrast material. T2*-weighted MRI is important in the detection and quantification of iron overload cardiomyopathy. Other hereditary entities for which comprehensive MRI has proven essential include Danon disease, familial dilated cardiomyopathy, hereditary muscular dystrophy, arrhythmogenic right ventricular cardiomyopathy, and ventricular noncompaction. As a result of the diagnostic power of cardiac MRI, cardiac MRI examinations are being requested with increasing frequency, not only in academic centers but also in community practices. The genetic background, pathophysiologic characteristics, and clinical presentation of patients with hereditary cardiomyopathy are described; the characteristic cardiac MRI features of hereditary cardiomyopathy are discussed; and the role of MRI in risk stratification, treatment, and prognostication in patients with cardiomyopathy is reviewed. ^©RSNA, 2022 Online supplemental material is available for this article.

Early start of enzyme replacement therapy in pediatric male patients with classical Fabry disease is associated with attenuated disease progression

BACKGROUND

Enzyme replacement therapy (ERT) slows disease progression of Fabry disease (FD), especially when initiated before the onset of irreversible organ damage. However, with the clinically asymptomatic progression of renal, cardiac and cerebral disease manifestations spanning decades, optimal timing of ERT initiation remains unclear.

METHODS

In this cross-sectional retrospective study, seven male FD patients with a classical disease phenotype (cFD) who started treatment with agalsidase-beta in childhood were evaluated after 10 years of treatment (median age at evaluation 24 years, range 14-26). Cardiac imaging (echocardiography and MRI), electrophysiological and biochemical data of these patients were compared to those of untreated male cFD patients (n = 23, median age 22 years, range 13-27).

RESULTS

Albuminuria was less common and less severe in treated patients (albumin to creatinine ratio, ACR 0-8.8 mg/mmol, median 0.4) compared to untreated patients (ACR 0-248 mg/mmol, median 3.7, p = 0.02). The treated group had a lower left ventricular mass, measured using echocardiography (median 80 g/m² versus 94 g/m², p = 0.02) and MRI (median 53 g/m² versus 68 g/m², p = 0.02). Myocardial fibrosis was absent in all included patients. eGFR was normal in all treated patients whereas 7/23 (30%) of untreated patients had abnormal eGFR. Cerebral manifestations did not differ.

CONCLUSIONS

Start of treatment with ERT before age 16, in male cFD patients is associated with reduced occurrence of renal and cardiac manifestations of FD, as assessed by intermediate endpoints. Confirmation that this approach delays or even prevents renal failure and cardiac events requires another decade of follow-up.

Utility of Cardiac Magnetic Resonance Imaging in the Diagnosis, Prognosis, and Treatment of Infiltrative Cardiomyopathies

PURPOSE OF REVIEW

Diagnosis of infiltrative cardiomyopathies can be challenging despite differences in clinical manifestations due to overlapping cardiac manifestations. We review the salient findings by cardiac magnetic resonance imaging that aids in diagnosis, as well the potential implications for prognosis and treatment.

RECENT FINDINGS

Cardiac magnetic resonance imaging has added substantially to our understanding of various infiltrative cardiomyopathies, and the addition of late gadolinium enhancement imaging and parametric mapping has yielded additional insights regarding potential diagnoses, prognosis, and therapy. Cardiac magnetic resonance imaging should be employed in the setting of suspected hypertrophic or infiltrative cardiomyopathies to aid in diagnosis. In the setting of cardiac amyloidosis and Fabry disease, there is data to suggest that cardiac magnetic resonance imaging is useful for risk stratification as well as for monitoring response to therapy.

Cardiac Imaging in Anderson-Fabry Disease: Past, Present and Future

Anderson-Fabrydisease is an X-linked lysosomal storage disorder caused by a deficiency in the lysosomal enzyme α-galactosidase A. This results in pathological accumulation of glycosphingolipids in several tissues and multi-organ progressive dysfunction. The typical clinical phenotype of Anderson-Fabry cardiomyopathy is progressive hypertrophic cardiomyopathy associated with rhythm and conduction disturbances. Cardiac imaging plays a key role in the evaluation and management of Anderson-Fabry disease patients. The present review highlights the value and perspectives of standard and advanced cardiovascular imaging in Anderson-Fabry disease.

Fabry Disease and the Heart: A Comprehensive Review

Fabry disease (FD) is an X-linked lysosomal storage disorder caused by mutations of the GLA gene that result in a deficiency of the enzymatic activity of α-galactosidase A and consequent accumulation of glycosphingolipids in body fluids and lysosomes of the cells throughout the body. GB3 accumulation occurs in virtually all cardiac cells (cardiomyocytes, conduction system cells, fibroblasts, and endothelial and smooth muscle vascular cells), ultimately leading to ventricular hypertrophy and fibrosis, heart failure, valve disease, angina, dysrhythmias, cardiac conduction abnormalities, and sudden death. Despite available therapies and supportive treatment, cardiac involvement carries a major prognostic impact, representing the main cause of death in FD. In the last years, knowledge has substantially evolved on the pathophysiological mechanisms leading to cardiac damage, the natural history of cardiac manifestations, the late-onset phenotypes with predominant cardiac involvement, the early markers of cardiac damage, the role of multimodality cardiac imaging on the diagnosis, management and follow-up of Fabry patients, and the cardiac efficacy of available therapies. Herein, we provide a comprehensive and integrated review on the cardiac involvement of FD, at the pathophysiological, anatomopathological, laboratory, imaging, and clinical levels, as well as on the diagnosis and management of cardiac manifestations, their supportive treatment, and the cardiac efficacy of specific therapies, such as enzyme replacement therapy and migalastat.

Does left ventricular function predict cardiac outcome in Anderson-Fabry disease?

In Anderson–Fabry disease (AFD) the impact of left ventricular (LV) function on cardiac outcome is unknown. Noninvasive LV pressure–strain loop analysis is a new echocardiographic method to estimate myocardial work (MW). We aimed to evaluate whether LV function was associated with outcome and whether MW had a prognostic value in AFD. Ninety-six AFD patients (41.8 ± 14.7 years, 43.7% males) with normal LV ejection fraction were retrospectively evaluated. Inclusion criteria were sinus rhythm and ≥ 2-year follow-up. Standard echocardiography measurements, myocardial mechano-energetic efficiency (MEE) index, global longitudinal strain (GLS) and MW were evaluated. Adverse cardiac events were defined as composite of cardiac death, malignant ventricular tachycardia, atrial fibrillation and severe heart failure development. During a median follow-up of 63 months (interquartile range 37–85), 14 events occurred. Patient age, cardiac biomarkers, LV mass index, left atrium volume, E/Ea ratio, LV ejection fraction, MEE index, GLS and all MW indices were significantly related to adverse outcome at univariate analysis. After adjustment for clinical and echocardiographic parameters, which were significant at univariate analysis, GLS and MW resulted independent predictors of adverse events (p < 0.01). By ROC curve analysis, constructive MW ≤ 1513 mmHg% showed the highest sensitivity and specificity in predicting adverse outcome (92.9% and 86.6%, respectively). MW did not improve the predictive value of a model including clinical data, LV diastolic function and GLS. LV function impairment (both systolic and diastolic) is associated with adverse events in AFD. MW does not provide additive information over clinical features and systolic and diastolic function.

When to Use Cardiovascular Magnetic Resonance in Patients with Heart Failure

Use of cardiac magnetic resonance (CMR) to aid in diagnosis, management, and prognosis of ischemic and nonischemic cardiomyopathy has advanced tremendously in the past several decades. These advances have expanded our understanding of both ischemic and nonischemic cardiomyopathies while also allowing for new avenues of diagnosis and treatment. This review summarizes key concepts of CMR technology and CMR use in the diagnosis and prognosis in ischemic, infiltrative, inflammatory, and other nonischemic cardiomyopathies and discusses the use of CMR in the patient presenting with ventricular arrhythmia with unclear diagnosis and advances in CMR in the management cardiomyopathy.

Cardiovascular magnetic resonance (CMR) in restrictive cardiomyopathies

The restrictive cardiomyopathies constitute a heterogeneous group of myocardial diseases with a different pathogenesis and overlapping clinical presentations. Diagnosing them frequently poses a challenge. Echocardiography, electrocardiograms and laboratory tests may show non-specific changes. In this context, cardiac magnetic resonance (CMR) may play a crucial role in defining the diagnosis and guiding treatments, by offering a robust myocardial characterization based on the inherent magnetic properties of abnormal tissues, thus limiting the use of endomyocardial biopsy. In this review article, we explore the role of CMR in the assessment of a wide range of myocardial diseases causing restrictive patterns, from iron overload to cardiac amyloidosis, endomyocardial fibrosis or radiation-induced heart disease. Here, we emphasize the incremental value of novel relaxometric techniques such as T1 and T2 mapping, which may recognize different storage diseases based on the intrinsic magnetic properties of the accumulating metabolites, with or without the use of gadolinium-based contrast agents. We illustrate the importance of these CMR techniques and their great support when contrast media administration is contraindicated. Finally, we describe the useful role of cardiac computed tomography for diagnosis and management of restrictive cardiomyopathies when CMR is contraindicated.

Clinical Significance of Papillary Muscles on Left Ventricular Mass Quantification Using Cardiac Magnetic Resonance Imaging: Reproducibility and Prognostic Value in Fabry Disease

PURPOSE

Accurate and reproducible assessment of left ventricular mass (LVM) is important in Fabry disease. However, it is unclear whether papillary muscles should be included in LVM assessed by cardiac magnetic resonance imaging (MRI). The purpose of this study was to evaluate the reproducibility and predictive value of LVM in patients with Fabry disease using different analysis approaches.

MATERIALS AND METHODS

A total of 92 patients (44±15 y, 61 women) with confirmed Fabry disease who had undergone cardiac MRI at a single tertiary referral hospital were included in this retrospective study. LVM was assessed at end-diastole using 2 analysis approaches, including and excluding papillary muscles. Adverse cardiac events were assessed as a composite end point, defined as ventricular tachycardia, bradycardia requiring device implantation, severe heart failure, and cardiac death. Statistical analysis included Cox proportional hazard models, Akaike information criterion, intraclass correlation coefficients, and Bland-Altman analysis.

RESULTS

Left ventricular end-diastolic volume, end-systolic volume, ejection fraction, and LVM all differed significantly between analysis approaches. LVM was significantly higher when papillary muscles were included versus excluded (157±71 vs. 141±62 g, P<0.001). Mean papillary mass was 16±11 g, accounting for 10%±3% of total LVM. LVM with pap illary muscles excluded had slightly better predictive value for the composite end point compared with LVM with papillary muscles included based on the model goodness-of-fit (Akaike information criterion 140 vs. 142). Interobserver agreement was slightly better for LVM with papillary muscles excluded compared with included (intraclass correlation coefficient 0.993 [95% confidence interval: 0.985, 0.996] vs. 0.989 [95% confidence interval: 0.975, 0.995]) with less bias and narrower limits of agreement.

CONCLUSIONS

Inclusion or exclusion of papillary muscles has a significant effect on LVM quantified by cardiac MRI, and therefore, a standardized analysis approach should be used for follow-up. Exclusion of papillary muscles from LVM is a reasonable approach in patients with Fabry disease given slightly better predictive value and reproducibility.

Increased Spread of Native T1 Values Assessed With MRI as a Marker of Cardiac Involvement in Fabry Disease

OBJECTIVE. Cardiac involvement is the leading cause of mortality in Fabry disease. Noninvasive markers of cardiac involvement are needed to identify patients at high risk. The purpose of this study was to evaluate the diagnostic potential of segmental native T1 spread as an imaging biomarker in Fabry disease. SUBJECTS AND METHODS. In this prospective study, 43 patients with confirmed Fabry disease (mean ± SD age, 46±14 years; 70% women) and 17 healthy control subjects (mean ± SD age, 44 ±13 years; 53% women) underwent 3-T cardiac MRI including modified Look-Locker inversion recovery T1 mapping. Segmental native T1 spread was calculated as the difference between maximum and minimum segmental native T1 values, expressed as an absolute value and as a relative percentage of global native T1. RESULTS. Absolute and relative segmental native T1 spreads were significantly higher in patients with Fabry disease than in healthy control subjects (absolute median, 115 vs 98 ms [p = 0.004]; relative median, 9.9% vs 8.0% [p < 0.001]) and correlated positively with quantitative late gadolinium enhancement (absolute, r = 0.434, p < 0.001; relative, r = 0.436, p < 0.001), indexed left ventricular mass (absolute, r = 0.316, p = 0.01; relative, r = 0.347, p = 0.007), and global longitudinal strain (absolute, r = 0.289, p = 0.03; relative, r = 0.277, p = 0.03). Relative segmental native T1 spread differentiated patients with Fabry disease from healthy control subjects (odds ratio, 1.44 [95% CI, 1.10-1.89]; p = 0.009). Interob-server agreement was excellent for both absolute (intraclass correlation coefficient, 0.932) and relative (intraclass correlation coefficient, 0.926) segmental native T1 spread. CONCLUSION. Increased native T1 spread is a reproducible imaging biomarker of cardiac involvement in Fabry disease and may be particularly useful in the evaluation of patients who cannot undergo late gadolinium enhancement imaging.

Left Ventricular Mass and Wall Thickness Measurements Using Echocardiography and Cardiac MRI in Patients with Fabry Disease: Clinical Significance of Discrepant Findings

Purpose

To compare transthoracic echocardiography (TTE) and cardiac MRI measurements of left ventricular mass (LVM) and maximum wall thickness (MWT) in patients with Fabry disease and evaluate the clinical significance of discrepancies between modalities.

Materials and Methods

Seventy-eight patients with Fabry disease (mean age, 46 years ± 14 [standard deviation]; 63% female) who underwent TTE and cardiac MRI within a 6-month interval between 2008 and 2018 were included in this retrospective cohort study. The clinical significance of measurement discrepancies was evaluated with respect to diagnosis of left ventricular hypertrophy (LVH), eligibility for disease-specific therapy, and prognosis. Statistical analysis included paired-sample t test, Cox proportional hazard models, Akaike information criterion (AIC), and intraclass correlation coefficients.

Results

LVM indexed to body surface area (LVMI) and MWT were significantly higher at TTE compared with MRI (105 g/m² ± 48 vs 78 g/m² ± 36, P < .001 and 14 mm ± 4 vs 13 mm ± 5, P = .008, respectively). LVH classification was discordant between modalities in 23 patients (29%) (P < .001). Eligibility for disease-specific therapy based on MWT was discordant between modalities in 20 patients (26%) (P < .001). LVMI assessed with MRI was a better predictor of the combined endpoint compared with LVMI assessed with TTE (AIC, 127 vs 131). Interobserver agreement for LVMI and MWT was higher for MRI (intraclass correlation coefficient, 0.951 and 0.912, respectively) compared with TTE (intraclass correlation coefficient, 0.940 and 0.871; respectively).

Conclusion

TTE overestimates LVM and MWT and has lower reproducibility compared with cardiac MRI in Fabry disease. Measurement discrepancies between modalities are clinically significant with respect to diagnosis of LVH, prognosis, and treatment decisions.© RSNA, 2020.