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

Outcomes after septal myectomy in a cohort of patients with hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy (HCM) with left ventricular outflow tract obstruction that doesn't improve with pharmacological management often requires septal myectomy. However, there are few centers with experience in the practice of this procedure in our country. We describe the clinical and echocardiographic characteristics and postoperative outcomes of patients with HCM indicated for septal myectomy at a reference center in Colombia.

MATERIALS AND METHODS

Retrospective cohort study. Patients undergoing septal myectomy between 2010 and 2023 were included. Data were collected before and two years after surgery.

RESULTS

18 patients were included. The mean age was 50 years. The predominant functional class was NYHA II/III (94 %). Asymmetric septal variant (83.3 %) was the most frequent as well as obstructive phenotype (88.8 %). After myectomy, 70.5 % improved to NYHA I and 62.4 % had no significant gradient (<30 mmHg), and the most of patient improved SAM. One patient died post-procedure, anymore complications were presented.

DISCUSSION/CONCLUSIONS

Septal myectomy is a safe procedure, with clinical and echocardiographic improvement, with low complication rates.

The syndrome of inferior non-infarctional Q-waves due to segmental basal left ventricular hypertrophy

Non-infarctional Q-waves in general are often recorded in the ECG, and are attributed to anatomical and electrical ECG axis shifts, presence of accessory pathways, pregnancy, HCM, and other HCM-like segmental LV myocardial hypertrophic states, that are currently not fully characterized, as to their nosological nature. The present focused review concerns in particular inferior Q-waves and their association with segmental basal anterior and/or septal LV hypertophies due to HCM, and other not yet fully characterized basal segmental LV hypertophies. Insights from the currently available literature on the topic are reviewed, and varying opinions about the nature of such hypertophic states are discussed, with some suggestions, for what is needed to be done, for their further pathlogenetic characterization.

Mavacamten in real-life practice: Initial experience at a hypertrophic cardiomyopathy centre

AIMS

In clinical trials, mavacamten reduced left ventricular outflow tract obstruction (LVOTO) and improved symptoms in patients with symptomatic obstructive hypertrophic cardiomyopathy (oHCM). We aimed to share our real-world experience with the efficacy and safety of mavacamten in this patient population.

METHODS AND RESULTS

This retrospective, single-centre study included patients with symptomatic oHCM from March 2023 to November 2023. Inclusion criteria were oHCM, age >18 years, significant LVOTO (gradient >50 mmHg at rest or with Valsalva), New York Heart Association (NYHA) class ≥II despite maximally tolerated medical therapy, and left ventricular ejection fraction (LVEF) >55%. Patients were evaluated by echocardiography, NYHA class, electrocardiography and Holter monitor on each monthly visit for 3 months. A total of 31 patients were included in this study. The mean (SD) age was 58 (16.5) years, and 14 (45%) were female. Mean provoked left ventricular outflow tract gradient (LVOTG) reduced by -49.4 mmHg (P < 0.001) at 4 weeks, -59.2 mmHg (P < 0.001) at 8 weeks, and -60.8 mmHg (P < 0.001) at 12 weeks. Twenty-six of the 31 patients (83.8%) achieved an LVOTG ≤30 mmHg at Week 12. No major side effects were reported. Sixty-seven percent experienced ≥2 NYHA class improvements, LVEF remained above 55% and no dose titration was made.

CONCLUSIONS

Our real-world experience aligns with established mavacamten trial outcomes. Continuous vigilance and longitudinal investigations are needed to further assess potential long-term impacts.

An evidence review and gap analysis for obstructive hypertrophic cardiomyopathy

BACKGROUND

Patients with obstructive hypertrophic cardiomyopathy (oHCM) have a substantial humanistic, clinical, and economic burden due to the array of symptoms and complications associated with the disease. The objective of this review was to identify key evidence gaps related to oHCM, specifically in Europe, North America, and Japan.

METHODS

A targeted literature review was conducted using PubMed to identify English-language studies published between 2012 and 2022 assessing patients with HCM/oHCM in France, Germany, Italy, Spain, the United Kingdom (UK), the United States (US), Canada, and Japan. Outcomes of interest were epidemiology, natural history, pathophysiology, management, and clinical, economic, and humanistic burden. Identified studies were assessed qualitatively to characterize evidence gaps.

RESULTS

Among 2,262 abstracts and 531 full-text articles screened, 178 articles were included from PubMed searches. An additional 16 unique studies were identified via a supplemental Google Scholar search initially conducted in January 2023 and updated in July 2024. Disease natural history, pathophysiology, and management were well documented globally. Significant evidence gaps were noted for the epidemiology, treatment, and burden of oHCM. Although multiple US studies were identified on the clinical, economic, and humanistic burden of oHCM, and one clinical burden study was found for Japan, there was a lack of evidence for France, Germany, Italy, Spain, the UK, and Canada.

CONCLUSIONS

Major evidentiary gaps exist for the epidemiology, treatment, and burden of oHCM. Future research should address these gaps, with a specific focus on generating real-world evidence for Canada and European countries that will support the evaluation of emerging therapies in these regions.

Hypertrophic Cardiomyopathy: From Medical Treatment to Advanced Heart Failure Therapies

PURPOSE OF REVIEW

There has been much debate surrounding novel medical therapies and heart transplantation listing challenges in patients with hypertrophic cardiomyopathy (HCM).

RECENT FINDINGS

Recent clinical trials led to FDA approval of mavacamten (a cardiac myosin inhibitor), offering symptom relief and potentially delaying/avoiding invasive septal reduction therapies for some patients with HCM and left ventricular outflow obstruction (LVOTO). For those with refractory symptoms and end-stage heart failure, heart transplantation remains the gold standard. However, the concern for the organ allocation system failing to prioritize those individuals persists. HCM is a heterogeneous genetic condition with variable penetration and clinical presentation. Even though a large portion of patients remain asymptomatic, an important minority develops debilitating symptoms refractory to medical therapy. Post-HT short- and long-term outcomes are favorable. However, HT waitlist mortality remains high. For highly selected patients with HCM, a left ventricular assist device is a viable option.

Morphological anomalies in obstructive hypertrophic cardiomyopathy: Insights from four-dimensional computed tomography and surgical correlation

Hypertrophic cardiomyopathy (HCM) is a genetic disorder in which left ventricular outflow tract obstruction critically affects symptoms and prognosis. Traditionally, left ventricular outflow tract obstruction was primarily attributed to septal hypertrophy with systolic anterior motion of the mitral valve. However, recent evidence highlights significant contributions from the mitral valve and papillary muscle anomalies, as well as an apical-basal muscle bundle observed in HCM patients. Accurate morphological assessment is essential when considering septal reduction therapy. While transesophageal echocardiography and cardiac magnetic resonance are recommended for assessing the anomalous structures, four-dimensional computed tomography offers superior spatial resolution and multiplanar reconstruction capabilities. These features enable the evaluation of details of the morphological anomalies, such as the apical-basal muscle band, papillary muscle anomalies, subaortic stenosis, and right ventricular outflow tract obstruction. Based on the detailed assessment of these morphological features, four-dimensional computed tomography has been utilized for planning of surgical correction in a comprehensive HCM center. This approach facilitates the intervention strategies and may improve outcomes in septal reduction therapy for obstructive HCM.

Ablation of ventricular tachycardia after septal myectomy for hypertrophic cardiomyopathy

Electrocardiography and 3D mapping images of the case.

Management of hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy is an important cause of heart failure and arrhythmias, including sudden death, with a major impact on the healthcare system. Genetic causes and different phenotypes are now increasingly being identified for this condition. In addition, specific medications, such as myosin inhibitors, have been recently shown as potentially able to modify its symptoms, hemodynamic abnormalities and clinical course. Our article aims to provide a comprehensive outline of the epidemiology, diagnosis and treatment of hypertrophic cardiomyopathy in the current era.

Extended septal myectomy versus alcohol septal ablation: clinical results at a national referral centre

OBJECTIVES

Extended septal myectomy and alcohol septal ablation are 2 invasive treatments for hypertrophic obstructive cardiomyopathy. Our goal was to compare which of these techniques achieved a higher reduction in gradients, improvement in New York Heart Association (NYHA) functional class and reduction in medical treatment.

METHODS

It is a single-centre observational and retrospective analysis. We used multivariable regression analyses to assess the association of ablation/myectomy with different outcomes. The odds ratio or coefficient along with the 95% confidence interval was estimated according to the group and adjusted for the corresponding preprocedural variables and EuroSCORE II.

RESULTS

A total of 78 patients underwent septal myectomy, and 25 patients underwent alcohol septal ablation. Basal and Valsalva gradients after myectomy were reduced to a higher degree in comparison to ablation: 21.0 mmHg [P < 0.001, 95% confidence interval -30.7; -11.3], and 34.3 mmHg (P < 0.001, -49.1; -19.5) respectively. Those patients who received a myectomy had a lower probability of having moderate mitral regurgitation (odds ratio = 0.18, P = 0.054). Patients after septal myectomy were more likely to be NYHA functional class I (80.4%), whereas patients after ablation were more likely to be NYHA functional class III (48%). Both groups continued with beta-blocker therapy, but disopyramide could be discontinued after the myectomy in more cases (20%-36% vs 59%-1.3%; P < 0.001), and there was a tendency to discontinue calcium channel blockers (48%-16% vs 15.4-3.8%; P = 0.054).

CONCLUSIONS

After adjustment using preprocedural gradients and EuroSCORE II, myectomy achieves greater reduction in left ventricular outflow tract gradients compared to septal ablation.

Gene Therapy in Cardiology: Is a Cure for Hypertrophic Cardiomyopathy on the Horizon?

Hypertrophic cardiomyopathy (HCM) is the most common genetic cardiomyopathy worldwide, affecting approximately 1 in 500 individuals. Current therapeutic interventions include lifestyle optimisation, medications, septal reduction therapies, and, rarely, cardiac transplantation. Advances in our understanding of disease-causing genetic variants in HCM and their associated molecular mechanisms have led to the potential for targeted therapeutics and implementation of precision and personalised medicine. Results from preclinical research are promising and raise the question of whether cure of some subtypes of HCM may be possible in the future. This review provides an overview of current genetic therapy platforms, including 1) genome editing, 2) gene replacement, 3) allelic-specific silencing, and 4) signalling pathway modulation. The current applicability of each of these platforms within the paradigm of HCM is examined, with updates on current and emerging trials in each domain. Barriers and limitations within the current landscape are also highlighted. Despite recent advances, translation of genetic therapy for HCM to clinical practice is still in early development. In realising the promises of genetic HCM therapies, ethical and equitable access to safe gene therapy must be prioritised.

NAA10 gene related Ogden syndrome with obstructive hypertrophic cardiomyopathy: A rare case report

RATIONALE

Ogden syndrome is an exceptionally rare X-linked disease caused by mutations in the NAA10 gene. Reported cases of this syndrome are approximately 20 children and are associated with facial dysmorphism, growth delay, developmental disorders, congenital heart disease, and arrhythmia.

PATIENT CONCERNS

We present the clinical profile of a 3-year-old girl with Ogden syndrome carrying a de novo NAA10 variant [NM_003491:c.247C>T, p.(Arg83Cys)]. During infancy, she exhibited features such as left ventricular hypertrophy, protruding eyeballs, and facial deformities.

DIAGNOSIS

Clinical diagnosis included Ogden syndrome, congenital heart disease (obstructive hypertrophic cardiomyopathy, left ventricular outflow tract obstruction, mitral valve disease, tricuspid valve regurgitation), tonsillar and adenoidal hypertrophy, and speech and language delay.

INTERVENTIONS

The girl was considered to have hypertrophic cardiomyopathy (HCM) and received oral metoprolol as a treatment for HCM at our hospital. The drug treatment effect was not ideal, and her hypertrophy myocardial symptoms were aggravated and she had to be hospitalized for surgery.

OUTCOMES

The girl underwent a modified Morrow procedure under cardiopulmonary bypass and experienced a favorable postoperative recovery. No pulmonary infections or significant complications were observed during this period. The patient's family expressed satisfaction with the treatment process.

LESSONS

The case emphasizes the HCM of Odgen syndrome, and early surgery should be performed if drug treatment is ineffective.

Treatment Strategies for Hypertrophic Cardiomyopathy: Surgical

Septal myectomy is a well-established procedure for septal reduction in patients with obstructive hypertrophic cardiomyopathy (HCM) who have not responded to medical treatment. The surgical approach is tailored to the unique pathophysiology and septal morphology of the patient. Extended transaortic myectomy is the standard procedure for patients with isolated subaortic obstruction, the most common type of HCM. However, transapical myectomy is a useful adjunct for patients with long or midventricular obstruction and is our preferred technique for ventricular enlargement in patients with severe symptomatic diastolic heart failure because of extensive apical hypertrophy. Septal myectomy provides excellent postoperative outcomes as regards symptom relief and functional improvement, and operative morbidity and mortality rates are low in experienced centers. This article summarizes our current surgical management of patients with HCM and details operative methods and outcomes.

Advances in the Management of Hypertrophic Cardiomyopathy Leading to Low Disease-Related Mortality in 2023

Hypertrophic cardiomyopathy (HCM) is a relatively common often inherited heart disease encumbered throughout much of its almost 60-year history by the expectation of an unfavorable outcome with shortened longevity. However, it is notable that in 2023, most patients affected with HCM can now achieve normal or extended life expectancy without major disability because of a comprehensive constellation of management strategies that have evolved largely over the last 20 years. Distinct adverse disease pathways dictate high-benefit low-risk personalized treatments, without reliance on genomics and sarcomere mutations, including: primary prevention implantable defibrillators for sudden cardiac death prevention, surgical myectomy and percutaneous alcohol septal ablation to reverse heart failure symptoms, anticoagulation to prevent embolic stroke associated with concomitant atrial fibrillation, external defibrillation and hypothermia for out-of-hospital cardiac arrest, and heart transplant in a small patient subgroup with end-stage disease. Large cohort studies using these contemporary management strategies achieved remarkably low HCM-related mortality (0.5%/year) across all age groups, which is lower than in the other cardiac or noncardiac risks of living, and largely confined to nonobstructive patients with progressive heart failure, including those awaiting heart transplant.

Contemporary Surgical Management of Hypertrophic Cardiomyopathy

More than half of symptomatic patients with hypertrophic cardiomyopathy (HCM) have left ventricular outflow tract (LVOT) obstruction. Septal reduction therapy by septal myectomy can dramatically relieve exertional dyspnea, chest pain, and presyncope in properly selected patients and is an important management pathway for many patients. The distribution and degree of hypertrophy in patients with obstructive HCM are variable and, as discussed in this review, can influence clinical manifestations of the disease and surgical management. Subaortic septal hypertrophy is the most common phenotype of obstructive HCM associated with LVOT obstruction, but midventricular obstruction and apical hypertrophy may occur in isolation or in conjunction with subaortic septal hypertrophy. In many comprehensive HCM centers, transaortic septal myectomy is the preferred method of septal reduction therapy for symptomatic patients with obstructive HCM. Early surgical approaches aimed at alleviating left LVOT obstruction were hampered by a lack of understanding of the anatomy and pathophysiology of obstructive HCM. With the advent of Doppler echocardiography and, more recently, cardiac magnetic resonance imaging, surgeons can precisely assess the location and degree of obstruction, left ventricular size and function, and morphology and function of the mitral valve. This review discusses the current understanding of the role of septal myectomy in the management of patients with HCM and details contemporary operative methods.

Analysis and evaluation of patient-specific three-dimensional printing in complex septal myectomy

OBJECTIVES

This study aimed to assess the effectiveness of three-dimensional printing (3DP) in patients with complex hypertrophic cardiomyopathy requiring combined transaortic and transapical septal myectomy.

METHODS

We created 3DP models for 7 patients undergoing this surgery approach between June and October 2022 using silicone-like resin and conducted mock operations. The models were compared with echocardiography to identify abnormal muscle bundles and heart structures. These patients were then compared with a 1:2 matched group without 3DP, considering age, sex and additional operations.

RESULTS

The models mostly presenting with midventricular obstruction showed high consistency with original computed tomography data (r = 0.978, P < 0.001). 3DP identified more abnormal muscle bundles than echocardiography, primarily between the interventricular septum and apex. Excised specimens in mock operations mirrored those in actual myectomies. While cardiopulmonary bypass time was not significantly different, a near-20-min decrease was observed in the 3DP group (135.5 ± 31.1 vs 154.4 ± 36.6 min, P = 0.054).

CONCLUSIONS

While no significant differences in surgical outcomes were observed, 3DP appeared to enhance the visualization and understanding of spatial structures (average Likert scale score 4.0), potentially contributing to surgical proficiency (overall rating score 3.9). The use of 3DP may offer additional value in the preparation and execution of operations for complex hypertrophic cardiomyopathy cases.

Tailored Planning of Surgical Myectomy in Obstructive Hypertrophic Cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is a genetic myocardial disease characterized by abnormal thickening of the myocardium caused by myocardial disarray and interstitial fibrosis. HCM is associated with sudden cardiac-related events, such as ventricular fibrillation, tachycardia, and syncope. Moreover, left ventricular or midcavity obstruction due to the thickened myocardium can result in severe heart failure and mortality in patients with HCM. Surgical myectomy is a standard treatment option for patients with symptomatic obstructive HCM; however, it is a complex procedure that requires careful planning and execution to avoid complications, such as residual flow obstruction, persistent obliteration of the left ventricular cavity in systole, or iatrogenic ventricular septal defects. Therefore, a thorough understanding of the mechanics of HCM and precise evaluation of the location and extent of the hypertrophic myocardium to be removed are crucial for preoperative planning. Multiphase cardiac CT postprocessing is important for preoperative evaluation and planning of surgical myectomy in patients with HCM. In this review, the authors highlight use of multiphase cardiac CT with step-by-step postprocessing methods to simulate successful surgical myectomy. The transaortic surgeon's view on end-diastolic phase images accurately represents the surgical field. Moreover, myocardial segmentation can be used to generate volume-rendered images and three-dimensional printing. CT evaluation can also assist in identifying concurrent abnormalities, such as mitral valve or papillary muscle abnormalities. In addition to CT, other imaging modalities for preoperative evaluation of HCM and postmyectomy evaluation methods are presented. ©RSNA, 2023 Test Your Knowledge questions in the supplemental material and the slide presentation from the RSNA Annual Meeting are available for this article.

A systematic review of present and future pharmaco-structural therapies for hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is a common contemporary, treatable, genetic disorder that can be compatible with normal longevity. While current medical therapies are ubiquitous, they are limited by a lack of solid evidence, are often inadequate, poorly tolerated, and do not alter the natural disease course. As such, there has long been a need for effective, evidence-based, and targeted disease-modifying therapies for HCM. In this review, we redefine HCM as a treatable condition, evaluate current strategies for therapeutic intervention, and discuss novel myosin inhibitors. The majority of patients with HCM have elevated left ventricular outflow tract gradients, which predicts worse symptoms and adverse outcomes. Conventional pharmacological therapies for symptomatic HCM can help improve symptoms but are often inadequate and poorly tolerated. Septal reduction therapies (surgical myectomy and alcohol septal ablation) can safely and effectively reduce refractory symptoms and improve outcomes in patients with obstructive HCM. However, they require expertise that is not universally available and are not without risks. Currently, available therapies do not alter the disease course or the progressive cardiac remodeling that ensues, nor subsequent heart failure and arrhythmias. This has been regarded as an unmet need in the care of HCM patients. Novel targeted pharmacotherapies, namely cardiac myosin inhibitors, have emerged to reverse key pathophysiological changes and alter disease course. Their favorable outcomes led to the early Food and Drug Administration approval of mavacamten, a first-in-class myosin modulator, changing the paradigm for the pharmacological treatment of HCM.

Long-term outcomes of surgery for obstructive hypertrophic cardiomyopathy in a pediatric cohort

Background

Septal reduction therapy via septal myectomy or a modified Konno procedure is the mainstay of therapy for drug-refractory obstructive hypertrophic cardiomyopathy (HCM), although outcomes data on septal myectomy in pediatric patients are limited. We evaluated long-term outcomes following surgery for obstructive HCM in a pediatric cohort.

Methods

We retrospectively reviewed patients age ≤18 years with obstructive HCM who underwent a left and/or right ventricular septal myectomy at our institution between 1992 and 2022. Primary endpoints were transplantation-free survival, freedom from HCM-related death, and cumulative probability of HCM-related reintervention. We further evaluated outcomes in patients with and without Noonan syndrome or other RASopathies.

Results

Thirty-seven patients (median age, 7.4 years; interquartile range [IQR], 3.4-12.9 years) underwent transaortic septal myectomy. A combined modified Konno procedure was performed in 5 patients (13.9%). Sixteen patients (43.2%) had a RASopathy. A concomitant right ventricular outflow tract resection was performed in 9 patients (24.3%). There was 1 (2.7%) in-hospital death and 4 late deaths at a median follow-up of 10.5 years (IQR, 0.1-29.3). Twenty-year transplant-free survival and freedom from HCM-related death were 80.6% (95% confidence interval [CI], 64.2%-100%) and 87.1% (95% CI, 71.8%-100%), respectively. The 20-year cumulative probability of HCM-related reintervention was 34.2% (95% CI, 12.8%-57.1%). Seven patients required a septal reintervention. There was no difference in any primary endpoints between patients with and without a RASopathy.

Conclusions

Surgery for obstructive HCM, including septal myectomy with and without a modified Konno procedure, may be performed with low morbidity and good long-term outcomes in pediatric patients. Recurrent outflow tract obstruction is not uncommon.

Evolving Contemporary Management of Atrial Fibrillation in Hypertrophic Cardiomyopathy

Atrial fibrillation (AF) is the most common sustained arrhythmia in hypertrophic cardiomyopathy (HCM) with clinical and subclinical episodes occurring in nearly one-half of patients. AF in HCM historically has been characterized as a decisive disease complication associated with substantial risk for thromboembolic stroke and increased morbidity and mortality. However, there have been many advances in treatment strategy resulting in improved outcomes for this patient group. For example, stroke risk in HCM has been greatly reduced by using systemic oral anticoagulation initiated after the first clinical (symptomatic) AF episode, usually with preference given to direct anticoagulants over warfarin. In contrast, stroke risk scoring systems (such as CHA2DS2-VASc score) are not informative in HCM given the substantial potential for stroke events in patients with low scores, and therefore should not be used for anticoagulation decisions in this disease. A novel risk score specifically designed for HCM (HCM-AF score) can reliably identify most patients with HCM at risk for future AF. Although a strategy focused on controlling ventricular rate is effective in asymptomatic (or minimally symptomatic) patients with AF, restoring and maintaining sinus rhythm is required for most patients with marked AF symptom burden and impaired quality of life. Several antiarrhythmic drugs such as sotalol, disopyramide, and amiodarone, can be effective in suppressing AF episodes; albeit safe, long-term efficacy is supported by only limited data. Catheter AF ablation has emerged as an important treatment option for some patients, although freedom from AF after a single ablation is relatively low (35% at 3 years), multiple ablations and the concomitant use of antiarrhythmic drugs can control AF with more than two-thirds of patients maintaining sinus rhythm at 5 years. Surgical AF ablation with biatrial Cox-Maze IV performed as an adjunctive procedure during myectomy can reduce symptomatic AF episodes (70% of patients free from AF at 5 years). For the vast majority of patients who have HCM with AF, the implementation of contemporary therapies has allowed for improved quality of life and low HCM-related mortality.

Mavacamten: a first-in-class myosin inhibitor for obstructive hypertrophic cardiomyopathy

Mavacamten is a first-in-class, targeted, cardiac-specific myosin inhibitor approved by the US Food and Drug Administration for the treatment of adults with symptomatic New York Heart Association Classes II and III obstructive hypertrophic cardiomyopathy (oHCM). Mavacamten was developed to target the hyper-contractile phenotype, which plays a critical role in the pathophysiology of the disease. In Phase 2 and 3 clinical trials, mavacamten was well tolerated, reduced left ventricular outflow tract gradients, improved exercise capacity and symptoms, and was associated with improvements in other clinically relevant parameters, such as patient-reported outcomes and circulating biomarkers. In addition, treatment with mavacamten was associated with evidence of favourable cardiac remodelling in multi-modality imaging studies. Mavacamten substantially reduced guideline eligibility for septal reduction therapy candidates with oHCM and drug-refractory symptoms. In this article, the available efficacy and safety data from completed and ongoing clinical studies of mavacamten in patients with symptomatic oHCM are reviewed. Longer term extension studies may help address questions related to the positioning of mavacamten in current oHCM management algorithms, interactions with background therapy, as well as the potential for disease modification beyond symptomatic relief of left ventricular outflow tract obstruction.

Age-Based Outcomes in Patients Who Underwent Septal Reduction Therapy

There are no national data on age-based outcomes of septal reduction therapy. Using the National Inpatient Sample, we included all adult patients who underwent septal myectomy (SM) or alcohol septal ablation (ASA) from 2005 to 2019. The primary objective was to evaluate the in-hospital mortality and new permanent pacemaker (PPM) placement after SM and ASA in 3 age groups. In total, 9,564 patients underwent SM and 5,084 underwent ASA. Compared with the age group 18 to 39 years, the odds of in-hospital mortality after SM were similar in age group 40 to 64 years and 4.46 times higher than in age group ≥65 years; the higher mortality in the older group was explained by higher co-morbidity burden on the risk-adjusted analysis. Furthermore, compared with age group 18 to 39 years, the odds of new PPM placement after SM were higher in the age groups 40 to 64 years and ≥65 years, despite the risk adjustment (adjusted odds ratio [AOR] 3.17, 95% confidence interval [CI] 1.33 to 7.58 and AOR 4.39, 95% CI 1.78 to 10.8, respectively). The odds of in-hospital mortality after ASA were similar in age groups 65 to 79 years and 18 to 64 years. However, the odds of in-hospital mortality were higher in the age group ≥80 years than in the age group 18 to 64 years, although this difference were not present after risk adjustment. The odds of new PPM after ASA were higher for the age groups 65 to 79 years and ≥80 years than age group 18 to 64 years, despite the risk adjustment (AOR 1.78, 95% CI 1.22 to 2.60 and AOR 3.10, 95% CI 2.09 to 6.57, respectively). Finally, we also estimated these absolute risks in different age groups. In conclusion, this national data will inform health care providers to better understand the aged-based risks of outcomes after septal reduction therapy.

Hypertrophic Cardiomyopathy-Current Challenges and Future Perspectives

Hypertrophic cardiomyopathy (HCM) is a myocardial disorder characterized by left ventricular (LV) hypertrophy, which cannot be entirely attributed to loading conditions such as valve or congenital heart disease or hypertension [...].

Invasive therapies for symptomatic obstructive hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is a genetic condition with multiple different genetic and clinical phenotypes. As awareness for HCM increases, it is important to also be familiar with potential treatment options for the disease. Treatment of HCM can be divided into two different categories, medical and interventional. Typically for obstructive forms of the disease, in which increased septal hypertrophy, abnormally placed papillary muscles, abnormalities in mitral valve or subvalvular apparatus, lead to dynamic left ventricular outflow tract (LVOT) obstruction, treatment is targeted at decreasing obstructive gradients and therefore symptoms. Medications like beta blockers, calcium channel blockers, disopyramide can often accomplish this. However, in patients with severe obstruction or symptoms refractory to medical therapy, either surgical correction of the LVOT obstruction or percutaneous via alcohol septal ablation, are treatment options. In this review, we will focus on the invasive treatment of hypertrophic obstructive cardiomyopathy.

Is Congenital Muscular Mitral-Aortic Discontinuity Another Feature of Obstructive Hypertrophic Cardiomyopathy? A Pathology Validation Study

Hypertrophic cardiomyopathy (HCM) is an inherited myocardial disease at risk of sudden cardiac death and heart failure, even requiring heart transplantation. A "muscular mitral-aortic discontinuity" has been reported during surgery in the obstructive form. We aimed to validate these findings through pathological analysis of HCM heart specimens from the cardiovascular pathology tissue registry. Hearts with septal asymmetric HCM from sudden cardiac death, other causes of death, or heart transplantation were included. Sex-matched and age-matched patients without HCM served as controls. Gross and histologic analysis of the mitral valve (MV) apparatus and the mitral-aortic continuity were performed. Thirty HCM hearts (median age, 29.5 years; 15 men) and 30 controls (median age, 30.5 years; 15 men) were studied. In HCM hearts, a septal bulging was present in 80%, an endocardial fibrous plaque in 63%, a thickening of the anterior MV leaflet in 56.7%, and an anomalous insertion of papillary muscle in 10%. All cases but 1 (97%) revealed a myocardial layer overlapping the mitral-aortic fibrous continuity on the posterior side, corresponding to the left atrial myocardium. A negative correlation between the length of this myocardial layer and the age and the anterior MV leaflet length was found. The length did not differ between HCM and controls. Pathologic study of obstructive HCM hearts does not confirm the existence of a "muscular mitral-aortic discontinuity". An extension of left atrial myocardium, overlapping posteriorly the intervalvular fibrosa, is rather visible, and its length decreases with age, possibly as a consequence of left atrial remodeling. Our study highlights the fundamental role of thorough gross examination and the value of organ retention for further analysis in order to validate new surgical and imaging findings.

Alcohol septal ablation for hypertrophic obstructive cardiomyopathy and bilateral lung transplantation for idiopathic pulmonary fibrosis: a case report

Background

We present an uncommon case of a patient with hypertrophic obstructive cardiomyopathy and idiopathic pulmonary fibrosis. The case demonstrates the importance of pre-transplant cardiology workup and the need of interdisciplinary approach in diagnosing the cause of dyspnoea.

Case summary

The 52-year-old male patient was diagnosed with idiopathic pulmonary fibrosis in 2019 and gradually became oxygen dependent due to progression of dyspnoea. Bilateral lung transplantation was recommended in 2021. During pre-transplant cardiology workup, the patient was diagnosed with hypertrophic cardiomyopathy with left ventricular outflow tract (LVOT) obstruction. Considering the high surgical risk of the patient, alcohol septal ablation was performed with subsequent decrease of LVOT gradient. Bilateral lung transplantation was successfully performed afterwards. The patient's symptoms improved to NYHA class II at one year follow-up.

Discussion

We present a rare case of combined cause of dyspnoea-coexistence of hypertrophic obstructive cardiomyopathy and idiopathic pulmonary fibrosis in one patient. Due to high surgical risk, the patient underwent alcohol septal ablation with successful elimination of LVOT gradient and subsequently bilateral lung transplantation.

First-in-Human Transapical Beating-Heart Septal Myectomy in Patients With Hypertrophic Obstructive Cardiomyopathy

BACKGROUND

To simplify surgical septal reduction therapy for hypertrophic obstructive cardiomyopathy (HOCM), we developed a novel transapical beating-heart septal myectomy (TA-BSM) procedure.

OBJECTIVES

In this study, we sought to evaluate the clinical utility of TA-BSM in a first-in-human trial.

METHODS

Patients with HOCM were enrolled if they presented with drug-refractory disabling symptoms. TA-BSM was performed via minithoracotomy with the use of our beating-heart myectomy device under echocardiographic guidance, without the use of cardiopulmonary bypass. Repeated resections were performed to tailor the extent of the septal myectomy for sufficient abolishment of left ventricular outflow tract (LVOT) obstruction and mitral regurgitation (MR). The primary outcome measure was procedural success, defined by resting/provoked LVOT gradient <30/50 mm Hg and residual MR grade ≤1+ (of 4+) at 3-month follow-up.

RESULTS

A total of 47 patients aged 12 to 77 years were enrolled. Of the 46 patients who were followed for 3 months, 42 achieved procedural success. The maximal LVOT gradient decreased from 86 mm Hg (IQR: 67-114 mm Hg) at baseline to 19 mm Hg (IQR: 14-28 mm Hg) at 3 months. MR grade was ≤1+ in 3 patients at baseline and in 45 patients at 3 months. One patient died on postoperative day 10 owing to device-unrelated reasons. Other major adverse events included 1 delayed ventricular septal perforation and 1 intraoperative left ventricular apical tear.

CONCLUSIONS

TA-BSM is a safe and efficient minimally invasive procedure for septal reduction of heterogeneous HOCM. Compared with conventional septal myectomy, TA-BSM provides real-time evaluation to guide resection while reducing surgical trauma. (Transapical Beating-Heart Septal Myectomy in Patients With Hypertrophic Obstructive Cardiomyopathy; NCT05332691).

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.