Alessandra Serio

Long-Term Outcome and Risk Stratification in Dilated Cardiolaminopathies

OBJECTIVES The aim of this study was to analyze the long-term follow-up of dilated cardiolaminopathies. BACKGROUND Lamin A/C (LMNA) gene mutations cause a variety of phenotypes. In the cardiology setting, patients diagnosed with idiopathic dilated cardiomyopathy (DCM) plus atrioventricular block (AVB) constitute the majority of reported cases. METHODS Longitudinal retrospective observational studies were conducted with 27 consecutive families in which LMNA gene defects were identified in the probands, all sharing the DCM phenotype. RESULTS Of the 164 family members, 94 had LMNA gene mutations. Sixty of 94 (64%) were phenotypically affected whereas 34 were only genotypically affected, including 5 with pre-clinical signs. Of the 60 patients, 40 had DCM with AVB, 12 had DCM with ventricular tachycardia/fibrillation, 6 had DCM with AVB and Emery-Dreifuss muscular dystrophy type 2 (EDMD2), and 2 had AVB plus EDMD2. During a median of 57 months (interquartile range 36 to 107 months), we observed 49 events in 43 DCM patients (6 had a later event, excluded from the analysis). The events were related to heart failure (15 heart transplants, 1 death from end-stage heart failure) and ventricular arrhythmias (15 sudden cardiac deaths and 12 appropriate implantable cardioverter-defibrillator interventions). By multivariable analysis, New York Heart Association functional class III to IV and highly dynamic competitive sports for >or=10 years were independent predictors of total events. By a bivariable Cox model, splice site mutations and competitive sport predicted sudden cardiac death. CONCLUSIONS Dilated cardiomyopathies caused by LMNA gene defects are highly penetrant, adult onset, malignant diseases characterized by a high rate of heart failure and life-threatening arrhythmias, predicted by New York Heart Association functional class, competitive sport activity, and type of mutation.

Prognostic relevance of the echocardiographic assessment of right ventricular function in patients with idiopathic pulmonary arterial hypertension

BACKGROUND In patients with idiopathic pulmonary hypertension (IPAH) progression of the disease and survival are related to the capability of the right ventricle to adapt to the chronically elevated pulmonary artery pressure. Although several echocardiographic variables have been associated with outcome in previous studies, a comparative evaluation of all right ventricular (RV) function indices obtainable at echocardiography has never been performed. METHODS 59 patients consecutively admitted in a tertiary referral centre because of IPAH (22 males, mean age 46.3+/-16.1 years, 68% in WHO class III/IV at referral) underwent right heart catheterization and echocardiography. During a median follow-up period of 52 months, 21 patients died and 2 underwent lung transplantation in emergency conditions. RESULTS The following parameters were associated with survival: tricuspid annular plane systolic excursion (TAPSE), RV fractional area change, degree of tricuspid regurgitation, inferior vena cava collapsibility, superior vena cava flow velocity pattern, left ventricular diastolic eccentricity index. Patients with TAPSE<or=15 mm and left ventricular eccentricity index >or=1.7 had the highest event rate (51.7 per 100 person year); patients with TAPSE>15 mm and mild or no tricuspid regurgitation had the lowest event rate (2.6 per 100 person year). CONCLUSIONS A comprehensive echocardiographic assessment of RV systolic and diastolic function based on TAPSE, left ventricular diastolic eccentricity index and degree of tricuspid regurgitation allows an accurate prognostic stratification of patients with IPAH.

Atlas of the clinical genetics of human dilated cardiomyopathy

AIM Numerous genes are known to cause dilated cardiomyopathy (DCM). However, until now technological limitations have hindered elucidation of the contribution of all clinically relevant disease genes to DCM phenotypes in larger cohorts. We now utilized next-generation sequencing to overcome these limitations and screened all DCM disease genes in a large cohort. METHODS AND RESULTS In this multi-centre, multi-national study, we have enrolled 639 patients with sporadic or familial DCM. To all samples, we applied a standardized protocol for ultra-high coverage next-generation sequencing of 84 genes, leading to 99.1% coverage of the target region with at least 50-fold and a mean read depth of 2415. In this well characterized cohort, we find the highest number of known cardiomyopathy mutations in plakophilin-2, myosin-binding protein C-3, and desmoplakin. When we include yet unknown but predicted disease variants, we find titin, plakophilin-2, myosin-binding protein-C 3, desmoplakin, ryanodine receptor 2, desmocollin-2, desmoglein-2, and SCN5A variants among the most commonly mutated genes. The overlap between DCM, hypertrophic cardiomyopathy (HCM), and channelopathy causing mutations is considerably high. Of note, we find that >38% of patients have compound or combined mutations and 12.8% have three or even more mutations. When comparing patients recruited in the eight participating European countries we find remarkably little differences in mutation frequencies and affected genes. CONCLUSION This is to our knowledge, the first study that comprehensively investigated the genetics of DCM in a large-scale cohort and across a broad gene panel of the known DCM genes. Our results underline the high analytical quality and feasibility of Next-Generation Sequencing in clinical genetic diagnostics and provide a sound database of the genetic causes of DCM.

Rationale and design of a trial evaluating the effects of losartan vs. nebivolol vs. the association of both on the progression of aortic root dilation in Marfan syndrome with FBN1 gene mutations.

Background The major clinical problem of Marfan syndrome (MFS) is the aortic root aneurysm, with risk of dissection when the root diameter approximates 5 cm. In MFS, a key molecule, transforming growth factor-β (TGF-β), normally bound to the extracellular matrix, is free and activated. In an experimental setting, TGF-β blockade prevents the aortic root structural damage and dilatation. The angiotensin receptor 1 blockers (sartanics) exert an anti-TGF-β effect; trials are now ongoing for evaluating the effect of losartan compared with atenolol in MFS. β-Adrenergic blockers are the drugs most commonly used in MFS. The third-generation β-adrenergic blocker nebivolol retains the β-adrenergic blocker effects on heart rate and further exerts antistiffness effects, typically increased in MFS. Methods The open-label phase III study will include 291 patients with MFS and proven FBN1 gene mutations, with aortic root dilation (z-score ≥2.5). The patients will be randomized to nebivolol, losartan and the combination of the two drugs. The primary end point is the comparative evaluation of the effects of losartan, nebivolol and the association of both on the progression of aortic root growth rate. Secondary end points include the pharmacokinetics of the two drugs, comparative evaluation of serum levels of total and active TGF-β, quantitative assessment of the expression of the mutated gene (FBN1, both 5′ and 3′), pharmacogenetic bases of drug responsiveness. The quality of life evaluation in the three groups will be assessed. Statistical evaluation includes an interim analysis at month 24 and conclusive analyses at month 48. Conclusion The present study will add information about pharmacological therapy in MFS, supporting the new application of angiotensin receptor 1 blockers and finding β-adrenergic blockers that may give more specific effects. Moreover, the study will further deepen understanding of the pathogenetic mechanisms that are active in Marfan syndrome through the pharmacogenomic and transcriptomic mechanisms that may explain MFS phenotype variability.

The MOGE(S) Classification of Cardiomyopathy for Clinicians

Most cardiomyopathies are familial diseases. Cascade family screening identifies asymptomatic patients and family members with early traits of disease. The inheritance is autosomal dominant in a majority of cases, and recessive, X-linked, or matrilinear in the remaining. For the last 50 years, cardiomyopathy classifications have been based on the morphofunctional phenotypes, allowing cardiologists to conveniently group them in broad descriptive categories. However, the phenotype may not always conform to the genetic characteristics, may not allow risk stratification, and may not provide pre-clinical diagnoses in the family members. Because genetic testing is now increasingly becoming a part of clinical work-up, and based on the genetic heterogeneity, numerous new names are being coined for the description of cardiomyopathies associated with mutations in different genes; a comprehensive nosology is needed that could inform the clinical phenotype and involvement of organs other than the heart, as well as the genotype and the mode of inheritance. The recently proposed MOGE(S) nosology system embodies all of these characteristics, and describes the morphofunctional phenotype (M), organ(s) involvement (O), genetic inheritance pattern (G), etiological annotation (E) including genetic defect or underlying disease/substrate, and the functional status (S) of the disease using both the American College of Cardiology/American Heart Association stage and New York Heart Association functional class. The proposed nomenclature is supported by a web-assisted application and assists in the description of cardiomyopathy in symptomatic or asymptomatic patients and family members in the context of genetic testing. It is expected that such a nomenclature would help group cardiomyopathies on their etiological basis, describe complex genetics, and create collaborative registries.

Gender‐specific differences in major cardiac events and mortality in lamin A/C mutation carriers

Mutations in the lamin A/C gene (LMNA) cause a variety of clinical phenotypes, including dilated cardiomyopathy. LMNA is one of the most prevalent mutated genes in dilated cardiomyopathy, and is associated with a high risk of arrhythmias, sudden cardiac death, and heart failure. There are few data on the impact of age and gender on cardiac disease penetrance and mortality.

Diagnostic work-up and risk stratification in X-linked dilated cardiomyopathies caused by dystrophin defects.

OBJECTIVES We sought to describe the diagnostic work-up, phenotype, and long-term evolution of dilated cardiomyopathy (DCM) associated with Dystrophin (DYS) defects. BACKGROUND X-linked DCM associated with DYS defects can be clinically indistinguishable from other types of DCM. METHODS The series comprises 436 consecutive male patients diagnosed with DCM. Patients underwent endomyocardial biopsy (EMB). Genetic testing employed multiplex polymerase chain reaction and multiple ligation dependent probe assay for deletions and direct sequencing of the 79 exons and flanking regions of the gene for point mutations or small rearrangements. RESULTS We identified DYS defects in 34 of 436 patients (7.8%) (onset age 34 ± 11 years, age range 17 to 54 years); 30 had proven X-linked inheritance. The 2 phenotypes included DCM with mild skeletal myopathy and/or increased serum creatine phosphokinase (n = 28) or DCM only (n = 6). The EMB showed defective dystrophin immunostain. The DYS defects consisted of 21 in-frame deletions and 11 out-of-frame deletions as well as 1 stop and 1 splice-site mutation. During a median follow-up of 60 months (interquartile range: 11.25 to 101.34 months) we observed 17 events, all related to heart failure (HF) (median event-free survival: 83.5 months). Eight patients (23%) underwent transplantation, and 9 (26%) died of HF while waiting for transplantation. Eight patients received an implantable cardioverter-defibrillator, although none had device intervention during a median follow-up of 14 months (interquartile range: 5 to 25 months). No patient died suddenly, suffered syncope, or developed life-threatening ventricular arrhythmias. CONCLUSIONS DYS-related DCM should be suspected in male patients with increased serum creatine phosphokinase (82%) and X-linked inheritance. The disease shows a high risk of end-stage HF but a lower risk of life-threatening arrhythmias.

Risk of dissection in thoracic aneurysms associated with mutations of smooth muscle alpha-actin 2 (ACTA2)

Objective To evaluate the prevalence and phenotype of smooth muscle alpha-actin (ACTA2) mutations in non-syndromic thoracic aortic aneurysms and dissections (TAAD). Design Observational study of ACTA2 mutations in TAAD. Setting Centre for Inherited Cardiovascular Diseases. Patients A consecutive series of 100 patients with TAAD. Exclusion criteria included genetically confirmed Marfan syndrome, Loeys–Dietz type 2, familial bicuspid aortic valve and Ehlers–Danlos type IV syndromes. Interventions Multidisciplinary clinical and imaging evaluation, genetic counselling and testing of ACTA2, and family screening. Main outcome measures Prevalence of ACTA2 mutations and corresponding phenotypes. Results TAAD was familial in 43 cases and sporadic in 57 cases. Five mutations in the familial TAAD group (12%) were identified that were absent in controls. The known p.Arg149Cys and the novel p.Asp82Glu, p.Glu243Lys and p.Val45Leu mutations affected evolutionarily conserved residues. The IVS4+1G>A mutation was novel. Of 14 affected relatives, 13 were carriers of the mutation identified in the corresponding proband while one deceased relative had no genetic test. Type A dissection was the first manifestation of aortic aneurysm in four probands and occurred unexpectedly in five relatives. The aortic aneurysm was age dependent and absent in mutated children. Of nine patients who had acute dissection, five died following surgery. At dissection, the size of the aortic aneurysm ranged from 40 mm to 95 mm. Extravascular, ocular, skeletal, nervous and pulmonary traits were variably associated with TAAD, with iris flocculi being most common. Conclusions Timely diagnosis of TAAD in the probands, genetic counselling and family screening identify predisposed relatives and prevent catastrophic aortic dissections.

When should cardiologists suspect Anderson-Fabry disease?

Anderson-Fabry disease is a lysosomal storage disorder caused by α-galactosidase defects and progressive intracellular accumulation of globotriaosylceramide. The disease can be specifically treated with enzyme replacement therapy. Hemizygous men and heterozygous women can develop cardiac disease. Whereas men experience the most severe clinical phenotype, clinical presentation in women varies from asymptomatic to severely symptomatic. The characteristic cardiac phenotype is left ventricular hypertrophy mimicking sarcomeric hypertrophic cardiomyopathy or hypertensive heart disease. Early or prehypertrophy cardiac involvement may escape detection, unless electrocardiographic clues are present. The cardiac markers that raise suspicion of Anderson-Fabry disease include a short PR interval without a δ wave and a prolonged QRS interval, supraventricular and ventricular arrhythmias, and concentric left ventricular hypertrophy. Extracardiac features include renal failure, corneal deposits, and nervous, gastrointestinal, and cutaneous manifestations. Useful family data include cardiac and extracardiac traits in relatives and absence of male-to-male transmission. Symptoms are subtle, and the interval between the onset of symptoms and diagnosis may be as long as 20 years. As such, the diagnosis is typically late. Endomyocardial biopsy shows optically empty myocytes on light microscopy and dense osmiophilic bodies constituted of globotriaosylceramide on electron microscopy. Alpha-galactosidase A activity is reduced in hemizygous men but not in heterozygous women. Genetic testing is the gold standard for the diagnosis. In conclusion, a correct and timely diagnosis offers the possibility of disease-specific treatment that leads to sustained clinical benefits for cardiac and noncardiac signs and symptoms.

Regional abnormalities of myocardial deformation in patients with hypertrophic cardiomyopathy: correlations with delayed enhancement in cardiac magnetic resonance

Hypertrophic cardiomyopathy (HCM) is a genetic disease histologically characterized by a profound disarray of myocardial fibres and by local fibrosis. We sought to characterize regional left ventricular contractility in HCM patients using deformation analysis and to compare it with the presence or absence of delayed enhancement in cardiac magnetic resonance (CMR).