Angina in fabry disease reflects coronary small vessel disease

Long-Term Clinical-Pathologic Results of Enzyme Replacement Therapy in Prehypertrophic Fabry Disease Cardiomyopathy

BACKGROUND

The limited ability of enzyme replacement therapy (ERT) in removing globotriaosylceramide from cardiomyocytes is recognized for advanced Fabry disease cardiomyopathy (FDCM). Prehypertrophic FDCM is believed to be cured or stabilized by ERT. However, no pathologic confirmation is available. We report here on the long-term clinical-pathologic impact of ERT on prehypertrophic FDCM.

METHODS AND RESULTS

Fifteen patients with Fabry disease with left ventricular maximal wall thickness ≤10.5 mm at cardiac magnetic resonance required endomyocardial biopsy because of angina and ventricular arrhythmias. Endomyocardial biopsy showed coronary small-vessel disease in the angina cohort, and vacuoles in smooth muscle cells and cardiomyocytes ≈20% of the cell surface containing myelin bodies at electron microscopy. Patients received α-agalsidase in 8 cases, and β-agalsidase in 7 cases. Both groups experienced symptom improvement except 1 patients treated with α-agalsidase and 1 treated with β-agalsidase. After ERT administration ranging from 4 to 20 years, all patients had control cardiac magnetic resonance and left ventricular endomyocardial biopsy because of persistence of symptoms or patient inquiry on disease resolution. In 13 asymptomatic patients with FDCM, left ventricular maximal wall thickness and left ventricular mass, cardiomyocyte diameter, vacuole surface/cell surface ratio, and vessels remained unchanged or minimally increased (left ventricular mass increased by <2%) even after 20 years of observation, and storage material was still present at electron microscopy. In 2 symptomatic patients, FDCM progressed, with larger and more engulfed by globotriaosylceramide myocytes being associated with myocardial virus-negative lymphocytic inflammation.

CONCLUSIONS

ERT stabilizes storage deposits and myocyte dimensions in 87% of patients with prehypertrophic FDCM. Globotriaosylceramide is never completely removed even after long-term treatment. Immune-mediated myocardial inflammation can overlap, limiting ERT activity.

Fabry Disease: Cardiac Implications and Molecular Mechanisms

PURPOSE OF REVIEW

This review explores the interplay among metabolic dysfunction, oxidative stress, inflammation, and fibrosis in Fabry disease, focusing on their potential implications for cardiac involvement. We aim to discuss the biochemical processes that operate in parallel to sphingolipid accumulation and contribute to disease pathogenesis, emphasizing the importance of a comprehensive understanding of these processes.

RECENT FINDINGS

Beyond sphingolipid accumulation, emerging studies have revealed that mitochondrial dysfunction, oxidative stress, and chronic inflammation could be significant contributors to Fabry disease and cardiac involvement. These factors promote cardiac remodeling and fibrosis and may predispose Fabry patients to conduction disturbances, ventricular arrhythmias, and heart failure. While current treatments, such as enzyme replacement therapy and pharmacological chaperones, address disease progression and symptoms, their effectiveness is limited. Our review uncovers the potential relationships among metabolic disturbances, oxidative stress, inflammation, and fibrosis in Fabry disease-related cardiac complications. Current findings suggest that beyond sphingolipid accumulation, other mechanisms may significantly contribute to disease pathogenesis. This prompts the exploration of innovative therapeutic strategies and underscores the importance of a holistic approach to understanding and managing 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.

Anderson-Fabry Disease: Red Flags for Early Diagnosis of Cardiac Involvement

Anderson-Fabry disease (AFD) is a lysosome storage disorder resulting from an X-linked inheritance of a mutation in the galactosidase A (GLA) gene encoding for the enzyme alpha-galactosidase A (α-GAL A). This mutation results in a deficiency or absence of α-GAL A activity, with a progressive intracellular deposition of glycosphingolipids leading to organ dysfunction and failure. Cardiac damage starts early in life, often occurring sub-clinically before overt cardiac symptoms. Left ventricular hypertrophy represents a common cardiac manifestation, albeit conduction system impairment, arrhythmias, and valvular abnormalities may also characterize AFD. Even in consideration of pleiotropic manifestation, diagnosis is often challenging. Thus, knowledge of cardiac and extracardiac diagnostic "red flags" is needed to guide a timely diagnosis. Indeed, considering its systemic involvement, a multidisciplinary approach may be helpful in discerning AFD-related cardiac disease. Beyond clinical pearls, a practical approach to assist clinicians in diagnosing AFD includes optimal management of biochemical tests, genetic tests, and cardiac biopsy. We extensively reviewed the current literature on AFD cardiomyopathy, focusing on cardiac "red flags" that may represent key diagnostic tools to establish a timely diagnosis. Furthermore, clinical findings to identify patients at higher risk of sudden death are also highlighted.

Cardiomyocyte Globotriaosylceramide Accumulation in Adult Male Patients with Fabry Disease and IVS4 + 919G>A GLA Mutation is Progressive with Age and Correlates with Left Ventricular Hypertrophy and Reduced Left Ventricular Ejection Fraction

Background

While cardiovascular complications are the most common cause of mortality in Fabry disease, the relationship between globotriaosylceramide (GL-3) accumulation, the hallmark of Fabry cardiomyopathy, and cardiac hypertrophy has not been fully elucidated.

Methods

We developed unbiased stereology protocols to quantify the ultrastrcture of Fabry cardiomyopathy. Endomyocardial biopsies from 10 adult male enzyme replacement therapy naïve Fabry patients with IVS4 + 919G>A GLA mutation were studied. The findings were correlated with cardiac MRI and clinical data.

Results

Ultrastructural parameters showed significant relationships with key imaging and clinical and functional variables. Average cardiomyocyte volume and GL-3 volume per cardiomyocyte were progressively increased with age. Eighty-four percent of left ventricular mass index (LVMI) variability was explained by cardiomyocyte nuclear volume, age and plasma globotriaosylsphingosine with cardiomyocyte nuclear volume being the only independent predictor of LVMI. Septal thickness was directly and left ventricular ejection fraction (LVEF) was inversely correlated with cardiomyocyte GL-3 accumulation. Sixty-five percent of left ventricular ejection fraction (LVEF) variability was explained by cardiomyocyte GL3 volume, serum α-galactosidase-A activity and age with cardiomyocyte GL3 volume being the only independent predictor of LVEF. Residual α-galactosidase-A activity was directly correlated with myocardial microvasculature density.

Conclusions

The unbiased stereological methods introduced in this study unraveled novel relationships between cardiomyocyte structure and important imaging and clinical parameters. These novel tools can help better understand Fabry cardiomyopathy pathophysiology.

Novel Genetic Microvascular Dysplasia Causing Hypoperfusion of Cardiac, Renal, and Cerebral Circulation

BACKGROUND

Microvascular disorders represent an uncommon site of tissue hypo-perfusion and damage. Various genetic and acquired causes can be involved. A 65-year-old man was admitted because of refractory angina, which he had had since the age of 30 years, micro-hematuria, and recurrent transitory ischemic attacks from the age of 64.

METHODS

Hematochemical studies, ECG, Holter monitoring, 2D-echo, cardiac magnetic resonance (CMR), CTA of cerebral vessels, endomyocardial coronary angiography, and kidney biopsy processes were undertaken. Gene mutation analysis was conducted using next-generation sequencing, which included more than 5000 genes associated with inherited diseases.

RESULTS

Hematochemical findings were unremarkable. The ECG, Holter, 2D-echo, and CTA of brain vessels were normal. Cerebral magnetic resonance showed the presence of multiple small foci of ischemia. Coronary and ventricular angiography showed normal arteries with remarkably slow flow and multiple biventricular micro-aneurysms. At the endomyocardial biopsy, five of seven arterioles presented severe lumen obstruction due to hypertrophy and disarray of the muscular coat. Similarly, obstructed pre-glomerular arteries with glomerular sclerosis were seen at the renal biopsy. Genetics identified mutations in the ABCC6, MMP2, and XYLT1 genes, which play pivotal roles in the extracellular matrix.

CONCLUSION

This study described a new genetic microvascular obstructive disease causing progressive hypo-perfusion of the human brain, heart, and kidney.

Advanced CMR Techniques in Anderson-Fabry Disease: State of the Art

Anderson-Fabry disease (AFD) is a rare multisystem X-linked lysosomal storage disorder caused by α-galactosidase A enzyme deficiency. Long-term cardiac involvement in AFD results in left ventricular hypertrophy and myocardial fibrosis, inducing several complications, mainly arrhythmias, valvular dysfunction, and coronary artery disease. Cardiac magnetic resonance (CMR) represents the predominant noninvasive imaging modality for the assessment of cardiac involvement in the AFD, being able to comprehensively assess cardiac regional anatomy, ventricular function as well as to provide tissue characterization. This review aims to explore the role of the most advanced CMR techniques, such as myocardial strain, T1 and T2 mapping, perfusion and hybrid imaging, as diagnostic and prognostic biomarkers.

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.

Inflammation across the spectrum of hypertrophic cardiac phenotypes

The hypertrophic cardiomyopathy phenotype encompasses a heterogeneous spectrum of genetic and acquired diseases characterized by the presence of left ventricular hypertrophy in the absence of abnormal cardiac loading conditions. This "umbrella diagnosis" includes the "classic" hypertrophic cardiomyopathy (HCM), due to sarcomere protein gene mutations, and its phenocopies caused by intra- or extracellular deposits, such as Fabry disease (FD) and cardiac amyloidosis (CA). All these conditions share a wide phenotypic variability which results from the combination of genetic and environmental factors and whose pathogenic mediators are poorly understood so far. Accumulating evidence suggests that inflammation plays a critical role in a broad spectrum of cardiovascular conditions, including cardiomyopathies. Indeed, inflammation can trigger molecular pathways which contribute to cardiomyocyte hypertrophy and dysfunction, extracellular matrix accumulation, and microvascular dysfunction. Growing evidence suggests that systemic inflammation is a possible key pathophysiologic process potentially involved in the pathogenesis of cardiac disease progression, influencing the severity of the phenotype and clinical outcome, including heart failure. In this review, we summarize current knowledge regarding the prevalence, clinical significance, and potential therapeutic implications of inflammation in HCM and two of its most important phenocopies, FD and CA.

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.

Myocardial infarction with non-obstructive coronary arteries in hypertrophic cardiomyopathy vs Fabry disease

BACKGROUND

Little is known about prevalence and predictors of myocardial infarction with non-obstructive coronary arteries (MINOCA) in Fabry disease (FD) and hypertrophic cardiomyopathy (HCM). We assessed and compared the prevalence and predictors of MINOCA in a large cohort of HCM and FD patients.

METHODS

In this multicenter, retrospective study we enrolled 2870 adult patients with HCM and 267 with FD. The only exclusion criterion was documented obstructive coronary artery disease. MINOCA was defined according to guidelines. For each patient we collected clinical, ECG and echocardiographic data recorded at initial evaluation.

RESULTS

Overall, 36 patients had MINOCA during a follow-up period of 4.5 ± 11.2 years. MINOCA occurred in 16 patients with HCM (0.5%) and 20 patients with FD (7.5%; p &lt; 0.001). The difference between the 2 groups was highly significant, also after adjustment for the main clinical, ECG and echocardiographic variables (OR 6.12; 95%CI 2.80-13.3; p &lt; 0.001). In the FD population MINOCA occurred in 17 out of 96 patients with left ventricle hypertrophy (LVH, 17.7%) and in 3 out of 171 patients without LVH (1.7%; OR 12.0; 95%CI 3.43-42.3; p &lt; 0.001). At multivariable analysis, voltage criteria for LVH at ECG (OR 7.3; 95%CI 1.93-27.7; p = 0.003) and maximal LV wall thickness at echocardiography (OR 1.15; 95%CI 1.05-1.27; p = 0.002) maintained an independent association with MINOCA. No major significant differences were found in clinical, ECG and echocardiographic findings between HCM patients with or without MINOCA.

CONCLUSIONS

MINOCA was rare in HCM patients, and 6-fold more frequent in FD patients. MINOCA may be considered a red flag for FD and aid in the differential diagnosis from HCM.

Late-Onset Fabry Disease Affecting the Kidneys and Liver While Sparing the Heart: A Case Report

Fabry disease (FD), also known as Anderson-Fabry disease, is an X-linked inherited lysosomal storage disorder caused by the deficiency or reduced activity of alpha-galactosidase A enzyme, which results in the accumulation of globotriaosylceramide (Gb3) in the cells. Atypical (late-onset) FD is characterized by the preserved residual activity of alpha-galactosidase A enzyme resulting in a later presentation in life than classic FD. Patients with late-onset FD are usually present in their third to seventh decades of life with the heart being the most commonly affected organ. FD can also affect the renal and gastrointestinal (GI) systems, however, in the literature, FD limited to the kidneys is scarcely reported and there is no data to suggest disease involvement of the liver. We present a rare case of late-onset FD affecting the kidneys and liver without cardiac or other organ involvement in a patient without having a family history of FD.

Downregulation of Mannose-6-Phosphate Receptors in Fabry Disease Cardiomyopathy: A Potential Target for Enzyme Therapy Enhancement

Background: The efficacy of enzyme replacement therapy (ERT) in mobilizing globotryaosylceramide (GB-3) from Fabry cardiomyocytes is limited. The mechanism involved is still obscure. Methods: Assessment of M6Pr, M6Pr-mRNA, and Ubiquitin has been obtained by Western blot analysis and real-time PCR of frozen endomyocardial biopsy samples, from 17 pts with FD, various degree of left ventricular hypertrophy, and maximal wall thickening (MWT) from 11.5 and 20 mm. The diagnosis and severity of FDCM followed definitions of GLA mutation, α-galactosidase A enzyme activity, cardiac magnetic resonance, and left ventricular endomyocardial biopsy with the quantification of myocyte hypertrophy and the extent of Gb-3 accumulation. All patients have received alpha or beta agalsidase for ≥3 years without a reduction in LV mass nor an increase in T1 mapping at CMR. Controls were surgical biopsies from 15 patients undergoing mitral valve replacement. Results: Protein analysis showed mean M6Pr in FDCM to be 5.4-fold lower than in a normal heart (4289 ± 6595 vs. 23,581 ± 4074, p = 0.0996) (p < 0.001): specifically, 9-fold lower in males, p = 0.009, (p < 0.001) and 3-fold lower in females, p = 0.5799, (p < 0.001) showing, at histology, a mosaic of normal and diseased cells. M6Pr-mRNA expression was normal, while ubiquitin showed an increase of 4.6 fold vs. controls (13,284 ± 1723 vs. 2870 ± 690, p = 0.001) suggesting that ubiquitin-dependent post-translational degradation is likely responsible for the reduction of M6Pr in FDCM. Conclusion: M6Pr expression is remarkably reduced in FDCM as a likely result of post-translational degradation. This may explain the reduced efficacy of ERT and be a therapeutic target for the enhancement of ERT activity.

Divergent Impact of Enzyme Replacement Therapy on Human Cardiomyocytes and Enterocytes Affected by Fabry Disease: Correlation with Mannose-6-phosphate Receptor Expression

Background: The impact of enzyme replacement therapy (ERT) on cardiomyocytes and intestinal cells, affected by Fabry disease (FD), is still unclear. Methods: Six patients with FD, including five family members with GLA mutation c.666delC and one with GLA mutation c.658C > T, manifesting cardiomyopathy and intestinal symptoms (abdominal pain, diarrhea and malabsorption) were included in the study. Clinical outcome, cardiac magnetic resonance (CMR), endomyocardial and gastro-intestinal biopsies were evaluated before and after 2 years of treatment with agalsidase-α (0.2 mg/kg every other week). Immunohistochemistry and Western blot assessments of mannose-6-phosphate receptors (IGF-II-R) on intestinal and myocardial frozen tissue were obtained at diagnosis and after 2 years of ERT. Results: After ERT left ventricular maximal wall thickness, ranging from pre (<10.5 mm) to mild (<15 mm) and moderate hypertrophy (16 mm), was not associated with significant changes at CMR. Degree of dyspnea, mean cardiomyocyte diameter and % vacuolated areas of cardiomyocytes, representing intracellular GL3, remained unmodified. In contrast, intestinal symptoms improved with disappearance of diarrhea, recovery of anemia and weight gain, correlating with near complete clearance of the enterocytes from GL3 inclusions. IGF-II-R expression was remarkably higher even at histochemistry in intestinal tissue compared with myocardium (p < 0.001) either at baseline and after ERT, thus justifying intestinal recovery. Conclusions: Human cells affected by FD may respond differently to ERT: while cardiomyocytes retain their GL3 content after 2 years of treatment, gastro-intestinal cells show GL3 removal with recovery of function. This divergent response may be related to differences in cellular turnover, as well as tissue IGF-II-R expression.

Coronary Microvascular Dysfunction Across the Spectrum of Cardiovascular Diseases: JACC State-of-the-Art Review

Coronary microvascular dysfunction (CMD) encompasses several pathogenetic mechanisms involving coronary microcirculation and plays a major role in determining myocardial ischemia in patients with angina without obstructive coronary artery disease, as well as in several other conditions, including obstructive coronary artery disease, nonischemic cardiomyopathies, takotsubo syndrome, and heart failure, especially the phenotype associated with preserved ejection fraction. Unfortunately, despite the identified pathophysiological and prognostic role of CMD in several conditions, to date, there is no specific treatment for CMD. Due to the emerging role of CMD as common denominator in different clinical phenotypes, additional research in this area is warranted to provide personalized treatments in this "garden variety" of patients. The purpose of this review is to describe the pathophysiological mechanisms of CMD and its mechanistic and prognostic role across different cardiovascular diseases. We will also discuss diagnostic modalities and the potential therapeutic strategies resulting from recent clinical studies.

Atherosclerosis in Fabry Disease-A Contemporary Review

Fabry disease (FD) is a lysosomal storage disorder characterised by a deficiency in the enzyme α-galactosidase A resulting in sphingolipid deposition which causes progressive cardiac, renal, and cerebral manifestations. The case illustrates a patient with FD who died suddenly, and medical examination demonstrated myocardial scarring and prior infarction. Angina is a frequent symptom in FD. Our own data are consistent with registry data indicating a high prevalence of risk factors for coronary artery disease (CAD) in FD that may accelerate conventional atherosclerosis. Patients with FD also have a higher high-density lipoprotein (HDL)/total cholesterol (T-Chol) ratio which may further accelerate atherosclerosis through expression of early atherosclerotic markers. Patients with FD may develop CAD both via classical atherosclerosis and through formation of thickened fibrocellular intima containing fibroblasts with storage of sphingolipids. Both mechanisms occurring together may accelerate coronary stenosis, as well as alter myocardial blood flow. Our data supports limited data that, although coronary flow may be reduced, the prevalence of epicardial coronary stenosis is low in FD. Microvascular dysfunction and arterial wall stress from sphingolipid deposition may form reactive oxygen species (ROS) and myeloperoxidase (MPO), key atherosclerotic mediators. Reduced myocardial blood flow in FD has also been demonstrated using numerous imaging modalities suggesting perfusion mismatch. This review describes the above mechanisms in detail, highlighting the importance of modifying cardiovascular risk factors in FD patients who likely develop accelerated atherosclerosis compared to the general population.

Anderson-fabry disease: role of traditional and new cardiac MRI techniques

Anderson-Fabry (FD) disease is a rare X-linked disorder caused by different mutations in the Galactosidase α (GLA) gene, which leads to α-galactosidase A enzyme deficiency and the storage of glycosphingolipids in different kinds of organs, included the heart. This results in myocardial inflammation and left ventricular hypertrophy (LVH) and fibrosis. Echocardiography and cardiac magnetic resonance (C-MRI), in particular with new techniques, such as mapping analysis, late gadolinium enhancement (LGE) assessment and strain imaging, are important tools that allow a correct diagnosis, discriminating FD from other hypertrophic heart conditions. C-MRI is able to detect tissue alterations in the early stages of the disease, when an appropriate treatment could be more effective, and it has a fundamental role in monitoring 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.

Genetics of renovascular hypertension in children

OBJECTIVE

In most cases of renovascular hypertension in children, the cause is unclear. The aim of this study was to investigate genetic variation as a factor in the development of renovascular hypertension in children.

METHODS

In a cohort of 37 unrelated children from a single tertiary referral center, exome sequencing was performed. We assessed variants in recognized and suspected disease genes and searched for novel ones with a gene-based variant-burden analysis.

RESULTS

In the majority of patients, exome sequencing could not identify causative variants. We found a pathogenic variant in a recognized associated disease gene in five patients (three pathogenic variants in NF1, one in ELN and a deletion of chromosome 7q11.23, consistent with Williams syndrome). In two other patients, (likely) pathogenic variants were found in putative renovascular hypertension genes (SMAD6 and GLA), with clinical implications for both. Ten additional patients carried variants of uncertain significance (VUS) in known (n = 4) or putative (n = 6) renovascular hypertension disease genes. Rare variant burden analysis yielded no further candidate genes.

CONCLUSION

Genetic contributors, such as germline mutations in NF1, ELN, 7q11.23del were present in only 5 out of 37 (14%) children with renovascular hypertension. Twelve other children (32%) had potentially causal variants identified, including a pathogenic variant in SMAD6; a vasculopathy gene hitherto unknown to link with renovascular hypertension. Most importantly, our data show that exome sequencing can rarely identify the cause of renovascular hypertension in nonsyndromic children. We suggest that nongenetic factors or somatic genetic variation will play a more important role.

An expert consensus document on the management of cardiovascular manifestations of Fabry disease

Fabry disease (FD) is an X-linked lysosomal storage disorder caused by pathogenic variants in the α-galactosidase A (GLA) gene that leads to reduced or undetectable α-galactosidase A enzyme activity and progressive accumulation of globotriaosylceramide and its deacylated form globotriaosylsphingosine in cells throughout the body. FD can be multisystemic with neurological, renal, cutaneous and cardiac involvement or be limited to the heart. Cardiac involvement is characterized by progressive cardiac hypertrophy, fibrosis, arrhythmias, heart failure and sudden cardiac death. The cardiac management of FD requires specific measures including enzyme replacement therapy or small pharmacological chaperones in patients carrying amenable pathogenic GLA gene variants and more general management of cardiac symptoms and complications. In this paper, we summarize current knowledge of FD-related heart disease and expert consensus recommendations for its management.

Fabry cardiomyopathy: Gb3-induced auto-reactive panmyocarditis requiring heart transplantation

Resistance to enzyme replacement therapy (ERT) is a major therapeutic challenge in Fabry disease (FD). Recent reports attribute to immune-mediated inflammation a main role in promoting disease progression and resistance to ERT. Aim of the study is to report a Gb3-induced auto-reactive panmyocarditis causing inefficacy of ERT and severe electrical instability, which required cardiac transplantation. Examining the explanted heart from a 57-year-old man with FD cardiomyopathy (CM) on 3-year ERT presenting incoming ventricular fibrillation, we documented a severe virus-negative myocarditis extended to cardiomyocytes, intramural coronary vessels, conduction tissue, and subepicardial ganglia. Serology was positive for anti-Gb3, anti-heart, and anti-myosin antibodies. In vitro Gb3 stimulation of patient's peripheral blood mononuclear cells (PBMC) induced high amount production of inflammatory cytokine IL1-β, IL-6, IL-8, and TNF-α. PBMC were stained using the monoclonal antibodies CD3-V500, CD4-V450, CD8-APCcy7, CD45RO-PerCPcy5.5 and CD27-FITC from BD Biosciences and CD56-PC7 from Bekman Coulter. The phenotypic analysis of PBMC showed a lower frequency of CD8 (9.2%) vs. 19.3% and NKT cells (1.6% vs. 2.4%) in Fabry patient respect to healthy donor, suggesting a possible homing to peripheral tissues. A Gb3-induced auto-reactive myocarditis is suggested as a possible cause of FDCM progression and ERT resistance. Immune-mediated inflammation of systemic Fabry cells may coexist and be controlled by implemental immunosuppressive therapy.

Multimodality Imaging Assessment of Fabry Disease

Fabry disease is a lysosomal storage disease with a variety of cardiac manifestations. Although not specific for a diagnosis of Fabry disease, certain cardiac imaging findings may be highly suggestive of the diagnosis of Fabry disease in previously undiagnosed patients or cardiac involvement for patients with a known diagnosis of Fabry disease. In this review, we explore the current applications of multimodality cardiac imaging in the diagnosis and monitoring of patients with Fabry disease. Additionally, data regarding tissue characterization by cardiac magnetic resonance imaging and novel nuclear imaging techniques and their role in evaluating phenotype development is discussed.

Ventricular fibrillation associated with vasospastic angina pectoris in Fabry disease: a case report

Background

Fabry disease (FD) is an X-linked lysosomal storage disorder resulting from a deficiency in alpha-galactosidase A. The major causes of death due to cardiac complications include life-threatening arrhythmias. In addition, life-threatening arrhythmias may be related to myocardial fibrosis assessed by late gadolinium enhancement (LGE).

Case summary

A 43-year-old man with sinus bradycardia and left ventricular hypertrophy was referred to our cardiology department. Family history includes unexplained hypertrophy and sick sinus syndrome in mother. Additionally, his plasma alpha-galactosidase A activity was low. He was subsequently diagnosed with FD. Enzyme replacement therapy using 1.0 mg/kg agalsidase-β was initiated. During the fifth administration, he developed ventricular fibrillation (VF). Electrocardiography conducted immediately before VF revealed ST elevation in the inferior leads with reciprocated ST depression. Cardiac magnetic resonance imaging showed no LGE in the myocardium. Coronary angiography showed no organic stenosis; moreover, coronary spasms were induced by an intracoronary acetylcholine injection. Ventricular fibrillation was not observed as the patient received calcium antagonists.

Discussion

This report suggests that vasospastic angina pectoris is associated with life-threatening arrhythmias in patient with FD without LGE.

Quantitative Myocardial Perfusion in Fabry Disease

BACKGROUND

Fabry disease (FD) is an X-linked lysosomal storage disease resulting in tissue accumulation of sphingolipids. Key myocardial processes that lead to adverse outcomes in FD include storage, hypertrophy, inflammation, and fibrosis. These are quantifiable by multiparametric cardiovascular magnetic resonance. Recent developments in cardiovascular magnetic resonance perfusion mapping allow rapid in-line perfusion quantification permitting broader clinical application, including the assessment of microvascular dysfunction. We hypothesized that microvascular dysfunction in FD would be associated with storage, fibrosis, and edema.

METHODS

A prospective, observational study of 44 FD patients (49 years, 43% male, 24 [55%] with left ventricular hypertrophy [LVH]) and 27 healthy controls with multiparametric cardiovascular magnetic resonance including vasodilator stress perfusion mapping. Myocardial blood flow (MBF) was measured and its associations with other processes investigated.

RESULTS

Compared with LVH- FD, LVH+ FD had higher left ventricular ejection fraction (73% versus 68%), more late gadolinium enhancement (85% versus 15%), and a lower stress MBF (1.76 versus 2.36 mL/g per minute). The reduction in stress MBF was more pronounced in the subendocardium than subepicardium. LVH- FD had lower stress MBF than controls (2.36 versus 3.00 mL/g per minute; P=0.002). Across all FD, late gadolinium enhancement and low native T1 were independently associated with reduced stress MBF. On a per-segment basis, stress MBF was independently associated with wall thickness, T2, extracellular volume fraction, and late gadolinium enhancement.

CONCLUSIONS

FD patients have reduced perfusion, particularly in the subendocardium with greater reductions with LVH, storage, edema, and scar. Perfusion is reduced even without LVH suggesting it is an early disease marker.

Microvascular dysfunction in infiltrative cardiomyopathies

Infiltrative heart diseases are characterized by myocardial tissue alterations leading to mechanical dysfunction which in turn develops into bi-ventricular congestive heart failure. Also the coronary microvasculature undergoes significant remodeling and dysfunction. The effects of the unbalance of the mechanical cross-talk between cardiac muscle and vessels and of the impairment of vasodilatory function can be measured non-invasively by means of positron emission tomography and cardiac magnetic resonance.

Diagnosis and treatment of the cardiovascular consequences of Fabry disease

Fabry disease (FD) has been a diagnostic challenge since it was first recognized in 1898, with patients traditionally suffering from considerable delay before a diagnosis is made. Cardiac involvement is the current leading cause of death in FD. A combination of improved enzyme assays, availability of genetic profiling, together with more organized clinical services for rare diseases, has led to a rapid growth in the prevalence of FD. The earlier and more frequent diagnosis of asymptomatic individuals before development of the phenotype has focussed attention on early detection of organ involvement and closer monitoring of disease progression. The high cost of enzyme replacement therapy at a time of constraint within many health economies, moreover, has challenged clinicians to target treatment effectively. This article provides an outline of FD for the general physician and summarizes the aetiology and pathology of FD, the cardiovascular consequences thereof, modalities used in diagnosis and then discusses current indications for treatment, including pharmacotherapy and device implantation.

Immune-Mediated Myocarditis in Fabry Disease Cardiomyopathy

Background Glycosphingolipid accumulation in Fabry cells generates a proinflammatory response that may influence disease evolution and responsiveness to enzyme replacement therapy. This study evaluated incidence, mechanism, and impact of myocarditis in Fabry disease cardiomyopathy ( FDCM ). Methods and Results Myocarditis, defined as CD 3+ T lymphocytes >7/mm2 associated with necrosis of glycolipid-laden myocardiocytes, was retrospectively evaluated in endomyocardial biopsies from 78 patients with FDCM : 13 with maximal wall thickness (MWT) <11 mm (group 1), 17 with MWT 11 to 15 mm (group 2), 30 with MWT 16 to 20 mm (group 3), and 18 with MWT >20 mm (group 4). Myocarditis was investigated by polymerase chain reaction for cardiotropic viruses, by serum antiheart and antimyosin antibodies, and by cardiac magnetic resonance. Myocarditis was recognized at histology in 48 of 78 patients with FDCM (38% of group 1, 41% of group 2, 66% of group 3, and 72% of group 4). Myocarditis was characterized by positive antiheart and antimyosin antibodies and negative polymerase chain reaction for viral genomes. CD 3+ cells/mm2 correlated with myocyte necrosis, antimyosin autoantibody titer, and MWT ( P<0.001, r=0.79; P<0.001, r=0.84; P<0.001, r=0.61, respectively). Cardiac magnetic resonance showed myocardial edema in 24 of 78 patients (31%): 0% of group 1, 23% of group 2, 37% of group 3, and 50% of group 4. Conclusions Myocarditis is detectable at histology in up to 56% of patients with FDCM . It is immune mediated and correlates with disease severity. It can be disclosed by antiheart/antimyosin autoantibodies and in the advanced phase by cardiac magnetic resonance. It may contribute to progression of FDCM and resistance to enzyme replacement therapy.

Anderson-Fabry disease in heart failure

Anderson-Fabry disease is an X-linked lysosomal storage disorder caused by mutations in the GLA gene that result in deficiency of the enzyme alpha-galactosidase A. The worldwide incidence of Fabry's disease is reported to be in the range of 1 in 40,000-117,000, although this value may be a significant underestimate given under recognition of symptoms and delayed or missed diagnosis. Deficiency in alpha-galactosidase A causes an accumulation of neutral glycosphingolipids such as globotriaosylceramide (Gb3) in lysosomes within various tissues including the vascular endothelium, kidneys, heart, eyes, skin and nervous system. Gb3 accumulation induces pathology via the release of pro-inflammatory cytokines, growth-promoting factors and by oxidative stress, resulting in myocardial extracellular matrix remodelling, left ventricular hypertrophy (LVH), vascular dysfunction and interstitial fibrosis. Cardiac involvement manifesting as ventricular hypertrophy, systolic and diastolic dysfunction, valvular abnormalities and conduction tissue disease is common in AFD and is associated with considerable cardiovascular morbidity and mortality from heart failure, sudden cardiac death and stroke-related death.

Evolution of cardiac pathology in classic Fabry disease: Progressive cardiomyocyte enlargement leads to increased cell death and fibrosis, and correlates with severity of ventricular hypertrophy‬‬‬‬‬‬‬‬

BACKGROUND

Fabry disease, an X-linked lysosomal storage disease, results from deficient α-galactosidase A (α-GalA) activity and the systemic accumulation of α-galactosyl-terminated glycosphingolipids. Two major phenotypes, "Classic" and "Later-Onset", lead to renal failure, and/or cardiac disease, and early demise. To date, the evolution and progression of the cardiac pathology and resultant clinical manifestations in family members of phenotype have not been well characterized.

METHODS AND RESULTS

In a Classic family with nine affected members (GLA mutation c.983delG), cardiac imaging, angiography, and cardiac biopsies were performed in four males and two heterozygous females. Tissues were examined histologically, ultrastructurally, and myocardial necrosis and apoptosis were evaluated by in situ ligation with hairpin probes. Increasing cardiac pathology correlated with ECG and cardiac magnetic resonance findings. Young affected males with "pre-hypertrophy" had 18-20μm cardiomyocyte diameters, <30% vacuolar areas in myocytes, and normal levels of necrosis and apoptosis. Patients with "moderate hypertrophy" (maximal wall thickness (MWT) ≤16mm) had 30-35μm cardiomyocyte diameters, ~45% vacuolar areas, and moderate levels of necrosis and apoptosis. In contrast, the oldest male with severe hypertrophy (MWT=21mm) had 38-40μm cell diameters, >60% vacuolar areas, and marked necrosis and apoptosis.

CONCLUSION

Progressive gender-specific cardiac pathology and clinical manifestations were documented in affected Classic family members. Increasing cardiomyocyte diameter was correlated with disease severity, age, and gender. Fibrosis was presumably caused by cell death of enlarged, substrate-engorged cardiomyocytes. These results support early enzyme therapy in Classic males to prevent/minimize irreversible cardiac damage.

Fabry disease: A fundamental genetic modifier of cardiac function

Fabry disease (FD) is an inherited X-linked metabolic storage disorder triggered by abnormalities in the GLA gene at Xq22, which leads to a deficiency in α-galactosidase A and massive accumulation of intralysosomal glycosphingolipids. Cardiac complications are very common in FD and are the main cause of late morbidity, as well as early mortality in both hemizygous men and heterozygous women. There is a need for a multidisciplinary approach to evaluation and management of FD patients as there is a wide range of presentation of FD, which varies with mutation and other organ involvement/dysfunction. An overview of common cardiac involvement and clinical characteristics in FD including: left ventricular hypertrophy (LVH), conduction abnormalities and arrhythmias, coronary artery disease and valvular infiltrative myopathy are provided in this review. Current therapeutic approaches such as enzyme replacement therapy as well as the emergence of novel therapeutic options such as gene therapy to optimize disease outcomes in FD patients will be highlighted in this paper.

Cardiac Troponin I: A Valuable Biomarker Indicating the Cardiac Involvement in Fabry Disease

Objectives

Assessment of the clinical severity of Fabry disease (FD), an X-linked, rare, progressive disorder based on a genetic defect in alpha-galactosidase is challenging, especially regarding cardiac involvement. The aim of the study was to evaluate the diagnostic value of cardiac troponin I (cTnI) in discriminating FD patients with cardiac involvement in a large FD patient cohort.

Methods

cTnI levels were measured with a contemporary sensitive assay in plasma samples taken routinely from FD patients. The assay was calibrated to measure cTnI levels ≥0.01 ng/ml. Elevated cTnI values (cut-off ≥0.04 ng/ml) were correlated with clinical data.

Results

cTnI was assessed in 62 FD patients (median age: 47 years, males: 36%). Elevated cTnI levels were detected in 23 (37%) patients. Patients with a cTnI elevation were older (median 55 years versus 36 years, p<0.001). Elevated cTnI levels were associated with the presence of a LVH (16/23 versus 1/39; OR 65.81, CI: 6.747–641.859; p<0.001). In almost all patients with a left ventricular hypertrophy (LVH) elevated cTnI levels were detected (16/17, 94%). Absolute cTnI levels in patients with LVH were higher than in those without (median 0.23 ng/ml versus 0.02 ng/ml; p<0.001). A cTnI level <0.04ng/ml had a high negative predictive value regarding the presence of a LVH (38/39, 97%). In a control group of non-FD patients (n = 17) with LVH (due to hypertension) none showed cTnI levels ≥0.01 ng/ml.

Conclusions

Elevated cTnI levels are common in FD patients, reflecting cardiac involvement. FD patients might benefit from a continuous cTnI monitoring.

Coronary artery bypass graft in a patient with Fabry's disease

Fabry's disease is a lysosomal storage disease characterized by intracellular accumulation of ceramide trihexoside resulting from alpha-galactosidase A deficiency. While the heart is often involved, coronary artery disease and its management in Fabry's disease patients are extremely rare clinical entities. We report a case of a 72-year-old man with left main disease in Fabry's disease with special consideration of the arterial wall pathology.

Electrocardiographic Changes and Arrhythmia in Fabry Disease

Fabry disease is an X-chromosome-linked lysosomal storage disease characterized by a deficient activity or, in most males, absence of the enzyme α-galactosidase A (a-Gal A) leading to systemic, primary lysosomal accumulation of globotriaosylceramide (Gb3) (1). Recent literature refers to an overall birth prevalence of 1:40,000–170,000; however, such data do not allow an estimation on an actual patient number suffering from Fabry disease (2). Multisystem morbidity commonly develops in childhood and, with progression of the disease, life-threatening complications often occur in adulthood, including renal failure, cardiovascular dysfunction, neuropathy, and stroke (3–6). Life expectancy is reduced by an average of 15 years in female patients and 20 years in male patients (7, 8). The pathognomonic Gb3 accumulation has been repeatedly observed over the past decades by many groups in vascular endothelial and smooth muscle cells, cardiomyocytes, cardiac conduction tissue, and valvular fibroblasts (3). Although incompletely described, it is likely that inflammatory and neurohormonal mechanisms are involved in subsequent cellular and vascular dysfunction, leading to tissue ischemia, hypertrophy, and fibrosis (9). Furthermore, recently published works on cardiomyocyte dysfunction and conduction tissue involvement have suggested that cardiac dysfunction may reflect increased myocardial nitric oxide production with oxidative damage of cardiomyocyte myofilaments and DNA, causing cell dysfunction and death, and accelerated conduction with prolonged refractoriness and electric instability (10, 11).

Increased oxidative stress contributes to cardiomyocyte dysfunction and death in patients with Fabry disease cardiomyopathy

Cardiac dysfunction of Fabry disease (FD) has been associated with myofilament damage and cell death as result of α-galactosidase A deficiency and globotriaosylceramide accumulation. We sought to evaluate the role of oxidative stress in FD cardiomyocyte dysfunction. Myocardial tissue from 18 patients with FD was investigated for the expression of inducible nitric oxide synthase (iNOS) and nitrotyrosine by immunohistochemistry. Western blot analysis for nitrotyrosine was also performed. Oxidative damage to DNA was investigated by immunostaining for 8-hydroxydeoxyguanosine (8-OHdG), whereas apoptosis was evaluated by in situ ligation with hairpin probes. iNOS and nitrotyrosine expression was increased in FD hearts compared with hypertrophic cardiomyopathy and normal controls. Remarkably, immunostaining was homogeneously expressed in FD male cardiomyocytes, whereas it was only detected in the affected cardiomyocytes of FD females. Western blot analysis confirmed an increase in FD cardiomyocyte protein nitration compared with controls. 8-OHdG was expressed in 25% of cardiomyocyte nuclei from FD patients, whereas it was absent in controls. The intensity of immunostaining for iNOS/nitrotyrosine correlated with 8-OHdG expression in cardiomyocyte nuclei. Apoptosis of FD cardiomyocytes was 187-fold higher than in controls, and apoptotic nuclei were positive for 8-OHdG. Cardiac dysfunction of FD reflects increased myocardial nitric oxide production with oxidative damage of cardiomyocyte myofilaments and DNA, causing cell dysfunction and death.

Continuous cardiac troponin I release in Fabry disease

BACKGROUND

Fabry disease (FD) is a rare lysosomal storage disorder also affecting the heart. The aims of this study were to determine the frequency of cardiac troponin I (cTNI) elevation, a sensitive parameter reflecting myocardial damage, in a smaller cohort of FD-patients, and to analyze whether persistent cTNI can be a suitable biomarker to assess cardiac dysfunction in FD.

METHODS

cTNI values were determined at least twice per year in 14 FD-patients (6 males and 8 females) regularly followed-up in our centre. The data were related to other parameters of heart function including cardiac magnetic resonance imaging (cMRI).

RESULTS

Three patients (21%) without specific vascular risk factors other than FD had persistent cTNI-elevations (range 0.05-0.71 ng/ml, normal: <0.01). cMRI disclosed late gadolinium enhancement (LGE) in all three individuals with cTNI values ≥0.01, while none of the 11 patients with cTNI <0.01 showed a pathological enhancement (p<0.01). Two subjects with increased cTNI-values underwent coronary angiography, excluding relevant stenoses. A myocardial biopsy performed in one during this procedure demonstrated substantial accumulation of globotriaosylceramide (Gb3) in cardiomyocytes.

CONCLUSION

Continuous cTNI elevation seems to occur in a substantial proportion of patients with FD. The high accordance with LGE, reflecting cardiac dysfunction, suggests that cTNI-elevation can be a useful laboratory parameter for assessing myocardial damage in FD.

Cross-sectional baseline analysis of electrocardiography in a large cohort of patients with untreated Fabry disease

BACKGROUND

Morphology and function of Fabry cardiomyopathy has been previously studied by echocardiography and cardiac magnetic resonance (CMR). However, the value of electrocardiography (ECG) in relation to these two techniques remains largely unknown.

METHODS

One hundred fifty genetically confirmed Fabry patients were investigated using a comprehensive clinical workup comprising 12-lead ECG, echocardiography, and CMR.

RESULTS

ECG parameters at rest [PR, P wave, QT, QTc, QT dispersion and time interval from the peak to the end of the T wave (Tpeak to Tend)] were normal in the entire cohort and did not distinguish between males and females or stages of cardiomyopathy. A significant positive correlation was found between left ventricular (LV) mass on CMR and both the QRS duration and the LV Sokolow index, with the highest values in male patients with an advanced cardiomyopathy stage. No prediction of late enhancement on CMR (a sign for replacement fibrosis) was possible by a single ECG parameter. However, the absence of ST or T alterations (in 37 of 38 patients) specifically excluded late enhancement on CMR.

CONCLUSION

Our data in a large cohort of Fabry patients, including all cardiomyopathy stages, show, in contrast to former assumptions, that ECG parameters are not suitable to stage Fabry cardiomoypathy. Most ECG parameters were normal in the complete cohort. However, the absence of ST or T alterations seems to almost exclude late enhancement on CMR in these patients.

High prevalence of myocarditis in patients with hypertensive heart disease and cardiac deterioration

AIMS

Structural abnormalities causing cardiac deterioration in hypertensive heart disease (HHD) are poorly understood. The aim of the study was to evaluate left ventricular (LV) myocardial changes in patients with HHD and cardiac failure.

METHODS AND RESULTS

Among 1229 patients undergoing an LV or biventricular endomyocardial biopsy because of unexplained LV dysfunction from 2000 to 2010, 45 had HHD. The HHD population had non-invasive assessment of cardiac wall thickness, diameters, and function; endomyocardial samples were processed for histology, immunohistochemistry, and polymerase chain reaction (PCR) for cardiotropic viruses. Mean LV end-diastolic diameter was 63.3 ± 5.9 mm, LV ejection fraction 29.7 ± 7.6%, and maximal wall thickness 12.8 ± 0.9 mm. At histology, hypertrophy with degeneration of cardiomyocytes, increased external/lumen ratio of intramural arterioles, and myocardial fibrosis were observed in 17 patients (38%). In the remaining 28 patients (62%), these histological changes were associated with myocarditis. Myocarditis was present in 40.4% of the cohort without HHD. PCR was negative in HHD without inflammation while it was positive in 10 subjects with myocarditis (enterovirus in 3 cases, adenovirus 4, influenza virus 3). Addition of immunosuppression to supportive therapy in the 18 virus-negative myocarditis subjects was followed at 6 months by significant recovery of LV function in 15 (83%; ejection fraction from 25.3 ± 9.3% to 49.5 ± 9.8%) while LV function improved to a minor extent ( ejection fraction from 25 ± 5.1% to 36 ± 4.4%) in 12 of 27 patients (44%) on supportive treatment alone.

CONCLUSION

Myocarditis is a major cause of cardiac deterioration in patients with HHD; its recognition may improve patient treatment and outcome.

Coronary telangiectasia associated with hypertrophic cardiomyopathy

AIMS

Coronary telangiectasia (CT) is a rare congenital anomaly causing ventricular shunt and myocardial ischaemia. Its prevalence, genetic background, and impact in human hypertrophic cardiomyopathy (HCM) are unknown and were therefore investigated in this study.

METHODS AND RESULTS

Among 445 patients with HCM, 195 had a coronary angiography and 124 a left ventricular endomyocardial biopsy. CT draining into the ventricular cavities was observed in 5 of 195 HCM patients (2.5%), whereas it was detected in 0.1% of 1000 consecutive subjects without congenital anomalies undergoing coronary angiography. Patients with CT-HCM underwent a total body computed tomography scan to investigate the presence of systemic vascular malformations. HCM-related MYH7, MYBPC3, TNNT2, and TPM1 genes and hereditary haemorragic telangiectasia-related endoglin and activin receptor-like kinase 1 genes were analysed. Histology, clinical profile, and outcome of CT-HCM patients were correlated with those of 22 control HCM patients. No mucocutaneous or systemic vascular malformations were detected. Gene analysis showed a MYH7 mutation in two patients, with an associated endoglin point mutation. Histology showed in the CT-HCM cohort a more pronounced myocardial fibrosis (29.8 ± 3.8%) compared with HCM controls (13 ± 2.6%), and disorganized cardiomyocytes separated by thin-walled large vessels adherent to the endocardium. Clinically, the CT-HCM cohort had a higher arrhythmic profile at diagnosis and increased incidence of implantable cardioverter defibrillator (ICD) implantations and arrhythmic deaths during a long-term follow-up.

CONCLUSION

CT is detectable in 2.5% of HCM patients vs. 0.1% of the general population; it may derive from a co-existing endoglin gene mutation and cause a prominent, potentially arrhythmogenic myocardial fibrosis.