Impact of secondary mitral valve chordal cutting on valve geometry in obstructive hypertrophic cardiomyopathy with marked septal hypertrophy.

AIMS: In patients with obstructive hypertrophic cardiomyopathy (HCM) and mild septal thickness undergoing myectomy, resecting fibrotic anterior mitral leaflet (AML) secondary chordae moves the mitral valve (MV) away from the outflow tract and ejection flow, reducing the need for a deep septal excision. Aim of the present study was to assess whether chordal resection has similarly favourable effects in patients with important hypertrophy, who represent the majority of patients with obstructive HCM. METHODS AND RESULTS: The MV position in the ventricular cavity, assessed from echocardiography as AML-annulus ratio, was compared before and after chordal resection in 150 consecutive HCM patients with important (≥20 mm) and 62 with mild (≤19 mm) septal thickness undergoing myectomy. Preoperatively, MV position was displaced towards the septum to a similar extent in both groups. Postoperatively, AML-annulus ratio increased of an equal degree in both groups, from 0.43 ± 0.05 to 0.55 ± 0.06 (P < 0.001) a 28% increase, and from 0.43 ± 0.06 to 0.55 ± 0.06 (P < 0.001) a 26% increase, respectively, indicating a similar MV shift away from the outflow tract. When AML-annulus ratio was compared in the study cohort and 124 normal subjects, MV position was within normal range in <4% of patients preoperatively and normalized in >50% postoperatively. CONCLUSIONS: In obstructive HCM, displacement of the MV apparatus into the outflow tract interferes with the ejection flow. Resection of fibrotic secondary chordae moves the MV apparatus away from the outflow tract and enlarges the outflow area independently of septal thickness, facilitating septal myectomy by reducing the need for a deep muscular excision.

Ventricular Septal Myectomy for Obstructive Hypertrophic Cardiomyopathy (Analysis Spanning 60 Years Of Practice): AJC Expert Panel.

Surgical myectomy remains the time-honored primary treatment for hypertrophic cardiomyopathy patients with drug refractory limiting symptoms due to LV outflow obstruction. Based on >50 years experience, surgery reliably reverses disabling heart failure by permanently abolishing mechanical outflow impedance and mitral regurgitation, with normalization of LV pressures and preserved systolic function. A consortium of 10 international currently active myectomy centers report about 11,000 operations, increasing significantly in number over the most recent 15 years. Performed in experienced multidisciplinary institutions, perioperative mortality for myectomy has declined to 0.6%, becoming one of the safest currently performed open-heart procedures. Extended myectomy relieves symptoms in >90% of patients by ≥ 1 NYHA functional class, returning most to normal daily activity, and also with a long-term survival benefit; concomitant Cox-Maze procedure can reduce the number of atrial fibrillation episodes. Surgery, preferably performed in high volume clinical environments, continues to flourish as a guideline-based and preferred high benefit: low treatment risk option for adults and children with drug refractory disabling symptoms from obstruction, despite prior challenges: higher operative mortality/skepticism in 1960s/1970s; dual-chamber pacing in 1990s, alcohol ablation in 2000s, and now introduction of novel negative inotropic drugs potentially useful for symptom management.

Not Only Diagnostic Yield: Whole-Exome Sequencing in Infantile Cardiomyopathies Impacts on Clinical and Family Management.

Whole-exome sequencing (WES) is a powerful and comprehensive tool for the genetic diagnosis of rare diseases, but few reports describe its timely application and clinical impact on infantile cardiomyopathies (CM). We conducted a retrospective analysis of patients with infantile CMs who had trio (proband and parents)-WES to determine whether results contributed to clinical management in urgent and non-urgent settings. Twenty-nine out of 42 enrolled patients (69.0%) received a definitive molecular diagnosis. The mean time-to-diagnosis was 9.7 days in urgent settings, and 17 out of 24 patients (70.8%) obtained an etiological classification. In non-urgent settings, the mean time-to-diagnosis was 225 days, and 12 out of 18 patients (66.7%) had a molecular diagnosis. In 37 out of 42 patients (88.1%), the genetic findings contributed to clinical management, including heart transplantation, palliative care, or medical treatment, independent of the patient's critical condition. All 29 patients and families with a definitive diagnosis received specific counseling about recurrence risk, and in seven (24.1%) cases, the result facilitated diagnosis in parents or siblings. In conclusion, genetic diagnosis significantly contributes to patients' clinical and family management, and trio-WES should be performed promptly to be an essential part of care in infantile cardiomyopathy, maximizing its clinical utility.

Evidence of evolution towards left midventricular obstruction in severe Anderson-Fabry cardiomyopathy.

AIMS: In Fabry cardiomyopathy, left ventricular outflow tract obstruction mimicking hypertrophic cardiomyopathy is a very rare finding, with few cases reported and successfully treated with cardiac surgery. In our population of patients with Fabry disease and severe left ventricular hypertrophy (LVH) at the time of diagnosis, we observed an evolution towards a midventricular obstructive phenotype. METHODS AND RESULTS: We present a case series of three classically affected Fabry male patients with significant diagnostic delay and severe cardiac involvement (maximal wall thickness >20 mm) at first evaluation. All patients developed midventricular obstructive form over time despite prompt initiation and optimal compliance to enzyme replacement therapy. The extension and distribution of the LVH, involving the papillary muscles, was the main mechanism of obstruction, unlike the asymmetric septal basal hypertrophy and the mitral valve abnormalities commonly seen as substrate of left ventricular outflow tract obstruction in hypertrophic cardiomyopathy. CONCLUSIONS: Fabry cardiomyopathy can evolve over time towards a midventricular obstructive form due to massive LVH in classically affected men with significant diagnostic delay and severe LVH before enzyme replacement therapy initiation. This newly described cardiac phenotype could represent an adverse outcome of the disease.

Surgical Single Stage Treatment for Obstructive Hypertrophic Cardiomyopathy and Aortic Arch Aneurysm.

Coexistence of obstructive hypertrophic cardiomyopathy and severe aortic pathology is extremely rare; nonetheless, the association between these two diseases is fascinating. Here we present a unique case report of a patient with obstructive hypertrophic cardiomyopathy and aortic arch aneurysm treated by a single surgical procedure.

Congenital Muscular Mitral-Aortic Discontinuity Identified in Patients With Obstructive Hypertrophic Cardiomyopathy.

BACKGROUND: The mitral valve is often structurally abnormal in hypertrophic cardiomyopathy (HCM). However, the mechanisms responsible for these abnormalities remain controversial. In 2016 we identified, at myectomy, muscular mitral-aortic discontinuity in 5 young patients with obstructive HCM. OBJECTIVES: This study sought to confirm our preliminary findings and assess the prevalence of muscular mitral-aortic discontinuity in obstructive HCM. METHODS: At our center, from January 2017 to April 2018, the area between the anterior mitral leaflet and aortic valve was inspected at myectomy in 106 consecutive patients with HCM. RESULTS: Muscular mitral-aortic discontinuity was identified in 28 (26%) patients and was significantly more common in younger than older patients (age 39 ± 13 years vs. 58 ± 11 years; p < 0.001). Muscular discontinuity was present in each of 6 patients aged <30 years but only 1 (2.7%) of 37 aged ≥60 years. Pathogenic sarcomere mutations were identified in 22 (79%) of 28 patients with and 24 (31%) of 78 without discontinuity (p < 0.001) and were associated with discontinuity independently of age (p = 0.021). Discontinuity mean length was 7.3 mm and was inversely related to age (p = 0.022). At echocardiography, the anterior mitral leaflet was longer in patients with than those without discontinuity (34 ± 4 mm vs. 29 ± 5 mm; p < 0.001). CONCLUSIONS: We report, for the first time, muscular mitral-aortic discontinuity in HCM. At myectomy, a long muscular discontinuity displaced the anterior mitral leaflet toward the apex in most young patients, was significantly associated with sarcomere mutations independent of age, and was extremely uncommon in older patients. These findings suggest that a long muscular mitral-aortic discontinuity could predispose to the development of outflow obstruction in young patients with sarcomere mutations.

Multidisciplinary evaluation and management of obstructive hypertrophic cardiomyopathy in 2020: Towards the HCM Heart Team.

Patients with hypertrophic cardiomyopathy (HCM) exhibit a variable phenotype with ventricular hypertrophy as the cardinal manifestation and left ventricular (LV) outflow tract obstruction (LVOTO) as a key pathophysiologic determinant. Patients with severe LVOTO usually present with exertional dyspnea, exertional syncope, and heart failure symptoms, while successful relief of LVOTO by pharmacological or invasive interventions leads to a dramatic improvement in clinical status. Proper management of obstructive HCM remains challenging and poses numerous clinical dilemmas. Since the development of surgical myectomy over half a century ago, progress in the management of LVOTO in HCM has paralleled technological advances in genetic testing, cardiac imaging, arrhythmic prophylaxis, cardiac surgery and interventional cardiology. These changes have been incorporated in dedicated scientific guidelines on both sides of the Atlantic. However, either the 2011 American guidelines or the 2014 European guidelines remain largely based on expert consensus for lack of recommendations with level of evidence A regarding any of the treatment options commonly employed in HCM. Consequently, management of obstructive HCM patients remains largely subjective and dependent on clinical judgment, local expertise, and patient preference. Following the trend that has emerged for other cardiac diseases amenable to invasive interventions, adequate evaluation and management of obstruction in HCM today requires a multidisciplinary team capable of optimizing referral, choosing the best available options, minimizing complications and ensuring state-of-the-art results. The concept of an HCM Heart Team is coming of age. This review aims to provide an update of available pharmacologic and invasive options for the management of LVOTO in HCM, either in adulthood or in childhood, highlighting areas for multidisciplinary integration and future development.

Structural abnormalities in hypertrophic cardiomyopathy beyond left ventricular hypertrophy by multimodality imaging evaluation.

BACKGROUND: Echocardiography- and cardiovascular magnetic resonance (CMR)-based studies have revealed a wide range of phenotypic manifestations in hypertrophic cardiomyopathy (HCM) apart from hypertrophy. This study sought to comprehensively describe a number of structural abnormalities in HCM beyond hypertrophy, by multimodality imaging. METHODS: A total of 100 HCM patients were prospectively enrolled, undergoing standard and contrast echocardiography, and CMR. Morphological characteristics involving mitral valve leaflets (MVL), subvalvular apparatus, and left ventricular cavity and wall were investigated. Seventy healthy volunteers served as control population. RESULTS: As assessed by echo, MVLs were longer in HCM patients than in controls (anterior method 1: 24[22,28] vs 19[18,20] mm, P < 0.01; anterior method 2: 27[24, 29] vs 21[19, 23] mm, P < 0.01; posterior: 15[12,19] vs 14[13,15] mm, P < 0.01). Abnormal chordal attachment to anterior MVL, anterior papillary muscle displacement, and accessory apical-basal muscle bundle were present in 42 (42%), 61 (61%), and 35 (35%) patients, respectively (P values vs controls <0.01); direct papillary muscle insertion into MVL and hypertrabeculation were found in two and five patients, respectively. Contrast echocardiography (n = 94) detected myocardial crypts in 15 patients (16%). Overall, 83% of HCM subjects had at least one of these phenotypic manifestations. Echocardiography and CMR agreement for MVL length was poor, while for structural characteristics was moderate to substantial (Cohen's Kappa: 0.53-1.00). Except for posterior MVL length and hypertrabeculation, the phenotypic characteristics studied had acceptable reproducibility by echocardiography and CMR. CONCLUSIONS: Structural abnormalities in HCM beyond hypertrophy are significantly common. Multimodality imaging approach to these HCM facets by echocardiography and CMR is feasible and desirable.

Role of Preoperative Cardiovascular Magnetic Resonance in Planning Ventricular Septal Myectomy in Patients With Obstructive Hypertrophic Cardiomyopathy.

In obstructive hypertrophic cardiomyopathy (HC), extreme heterogeneity of septal morphology makes septal myectomy particularly challenging. Although cardiovascular magnetic resonance (CMR) reconstructs ventricular anatomy with high spatial resolution, CMR is not used systematically to plan preoperatively septal myectomy. In this study, we report our results with using CMR to plan the extent of septal excision in 112 consecutive HC patients who subsequently underwent myectomy. Depth and length of the myectomy planned at CMR were compared with those of the septal muscle excised in a single piece in all patients. Anterior septum maximal thickness at CMR was 22 ± 5 mm and excised muscle thickness 9 ± 3 mm. Planned myectomy length was 35 ± 11 mm (range 17 to 65) and excised muscle length 38 ± 10 mm (range 10 to 70), indicating extension of septal resection to mid-cavity. Thickness and length of the planned myectomy showed a significant correlation with the excised muscle (R2 = 0.345; p <0.001; and R2 = 0.358; p <0.001, respectively). Deep septal crypts were identified at CMR in 12(11%) patients, preventing muscle excision from areas at increased risk of iatrogenic septal defect. Large aberrant muscle bundles that could decrease mid-cavity dimension were identified at CMR and excised in 26(23%) patients. In the 55 patients with postoperative CMR, qualitative comparison of pre and postoperative ventricular morphology showed a smooth and apically extended myectomy. In conclusion, CMR planning of septal myectomy provided high resolution images of septal morphology and allowed us to perform a standardized and apically extended septal excision that was associated with favorable outcome. Our novel approach could make myectomy more accessible to cardiovascular surgeons.

Exercise Hemodynamic and Functional Capacity After Mitral Valve Replacement in Patients With Ischemic Mitral Regurgitation: A Comparison of Mechanical Versus Biological Prostheses.

BACKGROUND: In patients with ischemic mitral regurgitation requiring mitral valve replacement (MVR), the choice of the prosthesis type is crucial. The exercise hemodynamic and functional capacity performance in patients with contemporary prostheses have never been investigated. To compare exercise hemodynamic and functional capacity between biological (MVRb) and mechanical (MVRm) prostheses. METHODS AND RESULTS: We analyzed 86 consecutive patients with ischemic mitral regurgitation who underwent MVRb (n=41) or MVRm (n=45) and coronary artery bypass grafting. All patients underwent preoperative resting echocardiography and 6-minute walking test. At follow-up, exercise stress echocardiography was performed, and the 6-minute walking test was repeated. Resting and exercise indexed effective orifice areas of MVRm were larger when compared with MVRb (resting: 1.30±0.2 versus 1.19±0.3 cm2/m2; P=0.03; exercise: 1.57±0.2 versus 1.18±0.3 cm2/m2; P=0.0001). The MVRm had lower exercise systolic pulmonary arterial pressure at follow-up compared with MVRb (41±5 versus 59±7 mm Hg; P=0.0001). Six-minute walking test distance was improved in the MVRm (pre-operative: 242±43, post-operative: 290±50 m; P=0.001), whereas it remained similar in the MVRb (pre-operative: 250±40, post-operative: 220±44 m; P=0.13). In multivariable analysis, type of prosthesis, exercise indexed effective orifice area, and systolic pulmonary arterial pressure were joint predictors of change in 6-minute walking test (ie, difference between baseline and follow-up). CONCLUSIONS: In patients with ischemic mitral regurgitation, bioprostheses are associated with worse hemodynamic performance and reduced functional capacity, when compared with MVRm. Randomized studies with longer follow-up including quality of life and survival data are required to confirm these results.

Intraoperative Diagnosis of Anderson-Fabry Disease in Patients With Obstructive Hypertrophic Cardiomyopathy Undergoing Surgical Myectomy.

Importance: Diagnostic screening for Anderson-Fabry cardiomyopathy (AFC) is performed in the presence of specific clinical red flags in patients with hypertrophic cardiomyopathy (HCM) older than 25 years. However, left ventricular outflow tract obstruction (LVOTO) has been traditionally considered an exclusion criteria for AFC. Objective: To examine a series of patients diagnosed with HCM and severe basal LVOTO undergoing myectomy in whom the diagnosis of AFC was suspected by the cardiac surgeon intraoperatively and confirmed by histological and genetic examinations. Design, Setting, and Participants: This retrospective analysis of patients undergoing surgical septal reduction strategies was conducted in 3 European tertiary referral centers for HCM from July 2013 to December 2016. Patients with a clinical diagnosis of obstructive HCM referred for surgical management of LVOTO were observed for at least 18 months after the procedure (mean [SD] follow-up, 33 [14] months). Main Outcomes and Measures: Etiology of patients with HCM who underwent surgical myectomy. Results: From 2013, 235 consecutive patients with a clinical diagnosis of HCM underwent septal myectomy. The cardiac surgeon suspected a storage disease in 3 patients (1.3%) while inspecting their heart samples extracted from myectomy. The mean (SD) age at diagnosis for these 3 patients was 42 (4) years; all were male. None of the 3 patients presented with extracardiac features suggestive of AFC. All patients showed asymmetrical left ventricular hypertrophy, with maximal left ventricular thickness in the basal septum (19-31 mm), severe basal LVOTO (70-120 mm Hg), and left atrial dilatation (44-57 mm). Only 1 patient presented with late gadolinium enhancement on cardiovascular magnetic resonance at the right ventricle insertion site. The mean (SD) age at surgical procedure was 63 (5) years. On tactile sensation, the surgeon felt a spongy consistency of the surgical samples, different from the usual stony-elastic consistency typical of classic HCM, and this prompted histological examinations. Histology showed evidence of intracellular storage, and genetic analysis confirmed a GLA A gene mutation (p.Asn215Ser) in all 3 patients. Conclusions and Relevance: Screening for AFC should be performed even in the absence of red flags in patients with HCM older than 25 years.

A Novel HRAS Mutation Independently Contributes to Left Ventricular Hypertrophy in a Family with a Known MYH7 Mutation.

Several genetic conditions can lead to left ventricular hypertrophy (LVH). Among them, hypertrophic cardiomyopathy (HCM), caused by mutations in sarcomere genes, is the most common inherited cardiac disease. Instead, RASopathies, a rare class of disorders characterized by neuro-cardio-facial-cutaneous abnormalities and sometimes presenting with LVH, are caused by mutations in the RAS-MAPK pathway. We report on a 62-years-old male who presented isolated severe obstructive LVH but did not carry the sarcomere mutation previously identified in his affected relatives. By exome sequencing, we detected a novel mutation in HRAS gene (NM_005343.2:p.Arg68Trp), present also in the proband's daughter, who showed mild LVH and severe intellectual disability. The cardiac phenotype was indistinguishable between family members carrying either mutation. In silico studies suggested that the mutated HRAS protein is constitutionally activated. Consistently, functional characterization in vitro confirmed elevated HRAS-GTP accumulation and downstream RAS-MAPK pathway activation that are known to drive cell proliferation in LVH. Our study emphasizes the role of RAS signaling in cardiac hypertrophy and highlights the complexity in differential diagnosis of RASopathies. In fact, the mild features of RASopathy and the recurrence of sarcomeric HCM in this family delayed the correct diagnosis until comprehensive genetic testing was performed.