Clinical and Echocardiographic Determinants of Long-Term Survival After Surgical Myectomy in Obstructive Hypertrophic Cardiomyopathy

Clinical Outcomes of Concomitant Coronary Artery Bypass Grafting During Ventricular Septal Myectomy

BACKGROUND

The clinical characteristics and survival outcomes of patients who underwent concomitant coronary artery bypass grafting during septal myectomy have not been well studied.

METHODS AND RESULTS

We reviewed patients who underwent both septal myectomy and coronary artery bypass grafting from 2009 to 2020. Causes of concomitant grafting and their impact on survival were analyzed. The median follow-up period was 5.1 years. A total of 320 patients underwent both grafting and myectomy. Of these, 69.7% and 28.1% underwent grafting attributed to atherosclerotic coronary artery disease and myocardial bridging, respectively. Patients who underwent grafting for coronary artery disease tended to be older, had a longer bypass time, and required more grafts compared with patients undergoing procedures because of myocardial bridging (all P<0.05). Postoperatively, the left ventricular outflow gradient significantly decreased from 85.4 mm Hg to 12.8 mm Hg (P<0.001) without perioperative death. The cumulative survival rates were 96.2% and 97.6% at 5 years in the coronary artery disease and myocardial bridging groups, respectively, and they were comparable to that of general myectomy cohort (hazard ratio [HR], 1.06 [95% CI, 0.47-2.36], P=0.895 and HR 0.75 [95% CI, 0.23-2.46], P=0.636, respectively). Sudden death accounted for 45.5% (5 of 11) of postoperative mortality. Analysis of composite end point events showed decreased morbidity with at least one arterial graft in the overall cohort (HR, 0.47 [95% CI, 0.23-0.94], P=0.034).

CONCLUSIONS

Concomitant grafting in septal myectomy was found to be a safe procedure. Patients who underwent such surgery experienced favorable postoperative outcomes comparable to those who underwent septal myectomy alone, with a 5-year survival rate of >95% and improved functional class of >90%.

Incremental prognostic value of left atrial strain in apical hypertrophic cardiomyopathy: a cardiovascular magnetic resonance study

OBJECTIVES

This study aimed to evaluate the prognostic value of left atrial (LA) strain in patients with apical hypertrophic cardiomyopathy (ApHCM), as assessed by cardiac magnetic resonance (CMR) imaging.

METHODS

Four hundred and five consecutive patients with ApHCM who underwent CMR examination were retrospectively included. The study endpoint included all-cause death, heart transplant, aborted sudden cardiac death, hospitalization for heart failure, stroke, and new-onset atrial fibrillation (AF).

RESULTS

After a median follow-up of 97 months, 75 patients (18.5%) reached the endpoint. Patients were divided into two groups based on the median LA reservoir strain of 29.4%. The group with lower LA reservoir strain had thicker maximum wall thickness, greater late gadolinium enhancement extent, and smaller end-diastolic volume index, stroke volume index, and cardiac index (all p < 0.02). For LA parameters, this subgroup showed greater diameter and volume index and worse ejection fraction, reservoir, conduit, and booster strain (all p < 0.001). In the multivariable model, age (HR 1.88, 95% CI: 1.06-3.31, p = 0.030), baseline AF (HR 2.95, 95% CI: 1.64-5.28, p < 0.001), LA volume index (LAVi) (HR 2.07, 95% CI: 1.21-3.55, p = 0.008) and LA reservoir strain (HR 2.82, 95% CI: 1.51-5.26, p = 0.001) were all associated with the outcome. Adding LAVi and LA reservoir strain in turn to the multivariable model (age and baseline AF) resulted in significant improvements in model performance (p < 0.001).

CONCLUSION

In ApHCM patients, LA reservoir strain is independently associated with cardiovascular risk events and has an incremental prognostic value.

CLINICAL RELEVANCE STATEMENT

Left atrial reservoir strain measured by cardiac magnetic resonance is highly correlated with the prognosis of apical hypertrophic cardiomyopathy and has potential incremental value in the prognosis of major adverse cardiac events.

KEY POINTS

Left atrial (LA) strain parameters may be useful for risk stratification and treatment of apical hypertrophic cardiomyopathy (ApHCM). Apical hypertrophic cardiomyopathy (ApHCM) is independently associated with LA morphology and function. Cardiac MR examination, especially its feature-tracking technology, provides the possibility to prognosticate ApHCM at an early stage.

Serial Changes in Ventricular Strain in Symptomatic Obstructive Hypertrophic Cardiomyopathy Treated With Mavacamten: Insights From the VALOR-HCM Trial

BACKGROUND

In severely symptomatic patients with obstructive hypertrophic cardiomyopathy, VALOR-HCM (A Study to Evaluate Mavacamten in Adults With Symptomatic Obstructive Hypertrophic Cardiomyopathy Who Are Eligible for Septal Reduction Therapy) demonstrated that mavacamten reduces the need for septal reduction therapy with sustained improvement in left ventricular (LV) outflow tract gradients and symptoms. Global longitudinal strain (GLS), a measure of regional myocardial function, is a more sensitive marker of systolic function. In VALOR-HCM, we assessed serial changes in LV and right ventricular (RV) strain.

METHODS

VALOR-HCM included 112 patients with symptomatic obstructive hypertrophic cardiomyopathy (mean, 60 years; 51% male; LV ejection fraction, 68%). Patients assigned to mavacamten at baseline continued the drug for 56 weeks (n=56) and those assigned to placebo (n=52) transitioned to mavacamten from weeks 16 to 56 (40-week exposure). LV-GLS and RV-GLS assessment was performed using a vendor-neutral software. Non-foreshortened apical (4-, 3-, and 2-chamber) views were used to obtain peak LV-GLS. RV focused 4-chamber view was used to calculate RV 4-chamber and free wall strain. A more negative strain value is favorable.

RESULTS

At baseline, the mean LV-GLS, RV 4-chamber, and free wall strain values were -14.7%, -22.2%, and -16.8%, respectively (all worse than reported normal means). In the total study sample, LV-GLS significantly improved from baseline to week 56 (P=0.02). Twelve patients had transient reduction in LV ejection fraction (<50%) requiring temporary drug interruption (including 3 permanent discontinuations). The LV-GLS in this subgroup was worse at baseline versus total study population (-11.4%), with no significant worsening from baseline through week 56 (P=0.64). Both free wall and 4-chamber RV-GLS remained unchanged from baseline to week 56 (P=0.62 and P=0.56, respectively).

CONCLUSIONS

In VALOR-HCM, treatment with mavacamten improved LV-GLS from baseline through week 56 (with no significant worsening of LV-GLS in patients with a reduction in LV ejection fraction ≤50%), suggesting a favorable long-term impact on regional LV systolic function. Additionally, there was no detrimental impact on RV systolic function.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT04349072.

Real-world experience with mavacamten in obstructive hypertrophic cardiomyopathy: Observations from a tertiary care center

BACKGROUND

In symptomatic obstructive hypertrophic cardiomyopathy (oHCM) patients, mavacamten is commercially approved to help improve left ventricular (LV) outflow tract (LVOT) gradients, symptoms, and reduce eligibility for septal reduction therapy (SRT) under the risk evaluation and mitigation strategy (REMS) program. We sought to prospectively report the initial real-world clinical experience with the use of commercially available mavacamten in a multi-hospital tertiary healthcare system.

METHODS

We studied the first 150 consecutive oHCM patients (mean age 65 years, 53% women, 83% on betablockers and 61% in New York Heart Association [NYHA] class III) who were initiated on 5 mg of mavacamten with dose titrations using symptom assessment and echocardiographic measurements of LVOT gradient and LV ejection fraction (LVEF) measurements. We measured changes in NYHA class, LVEF, LVOT gradients (resting and Valsalva) at baseline, 4, 8 and 12 weeks.

RESULTS

At 261 ± 143 days (range of 31-571 days), 69 (46%) patients had ≥1 NYHA class, and 27 (18%) additional patients had ≥2 NYHA class improvement. The mean Valsalva LVOT gradient decreased from 72 ± 43 mmHg at baseline to 29 ± 31 mmHg at 4 weeks, 29 ± 28 mmHg at 8 weeks and 30 ± 29 mmHg at 12 weeks (p < 0.001). At baseline, 100% patients had Valsalva LVOT gradients ≥30 mmHg, which reduced to 29% at 4 weeks, 28% at 8 weeks and 30% at 12 weeks. In 40 patients who reported no symptomatic improvement, the mean Valsalva LVOT gradient decreased from 73 ± 39 mmHg at baseline to 34 ± 27 mmHg at 4 weeks, 35 ± 28 mmHg at 8 weeks and 30 ± 24 mmHg at 12 weeks (P < 0.001). The mean LVEF at baseline was 66 ± 6% and changed to 64 ± 5% at 4 weeks, 63 ± 5% at 8 weeks and 62 ± 7% at 12 weeks (p < 0.0001). No patient underwent SRT, developed LVEF ≤30% or developed heart failure requiring admission. Three (2%) patients needed temporary interruption of mavacamten due to LVEF<50%.

CONCLUSIONS

In a real-world study in symptomatic oHCM patients at a multi-hospital tertiary care referral center, we demonstrate the efficacy and safety, along with the logistic feasibility of prescribing mavacamten under the REMS program.

Survival analysis and gender differences in hypertrophic cardiomyopathy proband patients referred for genetic testing

BACKGROUND

Hypertrophic cardiomyopathy (HCM) is believed to have low overall mortality rate, that could be influenced by gender, particularly among probands. We aimed to evaluate the survival rates and possible gender differences in a homogeneous cohort of HCM proband patients, referred for genetic testing, from the same geographical area, without differences in medical care access nor clinical referral pathways.

METHODS

we compared the mortality rates of a cohort of consecutive HCM probands referred for genetic testing (2000-2022), from a Spanish region (xxx1) with a centralized genetic testing pathway, with its control reference population by Ederer II method. Gender differences were analyzed.

RESULTS

Among the 649 HCM probands included in this study, there were significantly more men than women (61.3% vs 38.7, p < 0.05), with an earlier diagnosis (53.5 vs 61.1 years old, p < 0.05). Clinical evolution or arrhythmogenic HCM profile did no show no significant gender differences. Mean follow up was 9,8 years ±6,6 SD (9,9 ± 7 vs 9,6 ± 6,1, p = 0.59). No statistically significant differences in observed mortality, expected survival and excess mortality were found in the general HCM proband cohort. However, we found a significant excess mortality in female probands with HCM. No additional differences in analysis by genetic status were identified.

CONCLUSION

Expected survival in our HCM probands did not differ from its reference population. However, despite no gender differences in phenotype severity were identified, proband HCM women did present a diagnosis delay and worse mortality outcomes.

Flow inefficiencies in non-obstructive HCM revealed by kinetic energy and hemodynamic forces on 4D-flow CMR

Aims

Patients with non-obstructive hypertrophic cardiomyopathy (HCM) exhibit myocardial changes which may cause flow inefficiencies not detectable on echocardiogram. We investigated whether left ventricular (LV) kinetic energy (KE) and hemodynamic forces (HDF) on 4D-flow cardiovascular magnetic resonance (CMR) can provide more sensitive measures of flow in non-obstructive HCM.

Methods and results

Ninety participants (70 with non-obstructive HCM and 20 healthy controls) underwent 4D-flow CMR. Patients were categorized as phenotype positive (P+) based on maximum wall thickness (MWT) ≥ 15 mm or ≥13 mm for familial HCM, or pre-hypertrophic sarcomeric variant carriers (P-). LV KE and HDF were computed from 4D-flow CMR. Stroke work was computed using a previously validated non-invasive method. P+ and P- patients and controls had comparable diastolic velocities and LV outflow gradients on echocardiography, LV ejection fraction, and stroke volume on CMR. P+ patients had greater stroke work than P- patients, higher systolic KE compared with controls (5.8 vs. 4.1 mJ, P = 0.0009), and higher late diastolic KE relative to P- patients and controls (2.6 vs. 1.4 vs. 1.9 mJ, P < 0.0001, respectively). MWT was associated with systolic KE (r = 0.5, P < 0.0001) and diastolic KE (r = 0.4, P = 0.005), which also correlated with stroke work. Systolic HDF ratio was increased in P+ patients compared with controls (1.0 vs. 0.8, P = 0.03) and correlated with MWT (r = 0.3, P = 0.004). Diastolic HDF was similar between groups. Sarcomeric variant status was not associated with KE or HDF.

Conclusion

Despite normal flow velocities on echocardiography, patients with non-obstructive HCM exhibited greater stroke work, systolic KE and HDF ratio, and late diastolic KE relative to controls. 4D-flow CMR provides more sensitive measures of haemodynamic inefficiencies in HCM, holding promise for clinical trials of novel therapies and clinical surveillance of non-obstructive HCM.

2024 AHA/ACC/AMSSM/HRS/PACES/SCMR Guideline for the Management of Hypertrophic Cardiomyopathy: A Report of the American Heart Association/American College of Cardiology Joint Committee on Clinical Practice Guidelines

AIM

The "2024 AHA/ACC/AMSSM/HRS/PACES/SCMR Guideline for the Management of Hypertrophic Cardiomyopathy" provides recommendations to guide clinicians in the management of patients with hypertrophic cardiomyopathy.

METHODS

A comprehensive literature search was conducted from September 14, 2022, to November 22, 2022, encompassing studies, reviews, and other evidence on human subjects that were published in English from PubMed, EMBASE, the Cochrane Library, the Agency for Healthcare Research and Quality, and other selected databases relevant to this guideline. Additional relevant studies, published through May 23, 2023, during the guideline writing process, were also considered by the writing committee and added to the evidence tables, where appropriate.

STRUCTURE

Hypertrophic cardiomyopathy remains a common genetic heart disease reported in populations globally. Recommendations from the "2020 AHA/ACC Guideline for the Diagnosis and Treatment of Patients With Hypertrophic Cardiomyopathy" have been updated with new evidence to guide clinicians.

2024 AHA/ACC/AMSSM/HRS/PACES/SCMR Guideline for the Management of Hypertrophic Cardiomyopathy: A Report of the American Heart Association/American College of Cardiology Joint Committee on Clinical Practice Guidelines

AIM

The "2024 AHA/ACC/AMSSM/HRS/PACES/SCMR Guideline for the Management of Hypertrophic Cardiomyopathy" provides recommendations to guide clinicians in the management of patients with hypertrophic cardiomyopathy.

METHODS

A comprehensive literature search was conducted from September 14, 2022, to November 22, 2022, encompassing studies, reviews, and other evidence on human subjects that were published in English from PubMed, EMBASE, the Cochrane Library, the Agency for Healthcare Research and Quality, and other selected databases relevant to this guideline. Additional relevant studies, published through May 23, 2023, during the guideline writing process, were also considered by the writing committee and added to the evidence tables, where appropriate.

STRUCTURE

Hypertrophic cardiomyopathy remains a common genetic heart disease reported in populations globally. Recommendations from the "2020 AHA/ACC Guideline for the Diagnosis and Treatment of Patients With Hypertrophic Cardiomyopathy" have been updated with new evidence to guide clinicians.

Extended septal myectomy for obstructive hypertrophic cardiomyopathy and its impact on mitral valve function

AIMS

Septal myectomy is the treatment of choice for hypertrophic obstructive cardiomyopathy (HOCM). Around 30-60% of patients with HOCM have a secondary mitral valve regurgitation due to systolic anterior motion (SAM). We report our experience with extended septal myectomy and its impact on the incidence of concomitant mitral valve procedures.

METHODS

This is a retrospective study on 84 patients who underwent SM from January 2008 to February 2022. Surgical procedure was performed according to the concept of 'extended myectomy' described by Messmer in 1994. Follow-up outcomes in terms of survival, hospital admissions for heart failure or MV disease, cardiac reoperations, and pacemaker (PMK) implantation were recorded.

RESULTS

Mean age was 61 ± 15 years. Mitral valve surgery was performed in seven cases (8%); particularly only one patient without degenerative mitral valve disease underwent mitral valve surgery, with a plicature of the posterior leaflet. In-hospital mortality was 5%. Mitral valve regurgitation greater than mild was present in four patients (5%) at discharge. Twelve-year survival was 78 ± 22%. Cumulative incidence of rehospitalization for heart failure and rehospitalization for mitral valve disease was 10 ± 4 and 2.5 ± 2.5%, respectively. PMK implantation was 5% at discharge, with a cumulative incidence of 15 ± 7%. Freedom from cardiac reoperations was 100%.

CONCLUSION

Septal myectomy for HOCM is associated with good outcomes. Although concomitant surgery on the mitral valve to address SAM and associated regurgitation has been advocated, these procedures were needed in our practice only in patients with intrinsic mitral valve disease. Adequate myectomy addresses the underlying pathophysiology in most patients.

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.

Real-world candidacy to mavacamten in a contemporary hypertrophic obstructive cardiomyopathy population

AIMS

In the EXPLORER-HCM trial, mavacamten reduced left ventricular outflow tract obstruction (LVOTO) and improved functional capacity of symptomatic hypertrophic obstructive cardiomyopathy (HOCM) patients. We sought to define the potential use of mavacamten by comparing real-world HOCM patients with those enrolled in EXPLORER-HCM and assessing their eligibility to treatment.

METHODS AND RESULTS

We collected information on HOCM patients followed up at 25 Italian HCM outpatient clinics and with significant LVOTO (i.e. gradient ≥30 mmHg at rest or ≥50 mmHg after Valsalva manoeuvre or exercise) despite pharmacological or non-pharmacological therapy. Pharmacological or non-pharmacological therapy resolved LVOTO in 1044 (61.2%) of the 1706 HOCM patients under active follow-up, whereas 662 patients (38.8%) had persistent LVOTO. Compared to the EXPLORER-HCM trial population, these real-world HOCM patients were older (62.1 ± 14.3 vs. 58.5 ± 12.2 years, p = 0.02), had a lower body mass index (26.8 ± 5.3 vs. 29.7 ± 4.9 kg/m2 , p < 0.0001) and a more frequent history of atrial fibrillation (21.5% vs. 9.8%, p = 0.027). At echocardiography, they had lower left ventricular ejection fraction (LVEF, 66 ± 7% vs. 74 ± 6%, p < 0.0001), higher left ventricular outflow tract gradients at rest (60 ± 27 vs. 52 ± 29 mmHg, p = 0.003), and larger left atrial volume index (49 ± 16 vs. 40 ± 12 ml/m2 , p < 0.0001). Overall, 324 (48.9%) would have been eligible for enrolment in the EXPLORER-HCM trial and 339 (51.2%) for treatment with mavacamten according to European guidelines.

CONCLUSIONS

Real-world HOCM patients differ from the EXPLORER-HCM population for their older age, lower LVEF and larger atrial volume, potentially reflecting a more advanced stage of the disease. About half of real-world HOCM patients were found eligible to mavacamten.

Valvular heart disease and cardiomyopathy: reappraisal of their interplay

Cardiomyopathies and valvular heart diseases are typically considered distinct diagnostic categories with dedicated guidelines for their management. However, the interplay between these conditions is increasingly being recognized and they frequently coexist, as in the paradigmatic examples of dilated cardiomyopathy and hypertrophic cardiomyopathy, which are often complicated by the occurrence of mitral regurgitation. Moreover, cardiomyopathies and valvular heart diseases can have a shared aetiology because several genetic or acquired diseases can affect both the cardiac valves and the myocardium. In addition, the association between cardiomyopathies and valvular heart diseases has important prognostic and therapeutic implications. Therefore, a better understanding of their shared pathophysiological mechanisms, as well as of the prevalence and predisposing factors to their association, might lead to a different approach in the risk stratification and management of these diseases. In this Review, we discuss the different scenarios in which valvular heart diseases and cardiomyopathies coexist, highlighting the need for an improved classification and clustering of these diseases with potential repercussions in the clinical management and, particularly, personalized therapeutic approaches.

A systematic review and meta-analysis of sex differences in clinical outcomes of hypertrophic cardiomyopathy

Background

Hypertrophic cardiomyopathy (HCM) is recognized as the most prevalent form of genetic cardiomyopathy, and recent investigations have shed light on the existence of sex disparities in terms of clinical presentation, disease progression, and outcomes.

Objectives

This study aimed to systematically review the literature and perform a meta-analysis to comprehensively compare the clinical outcomes between female and male patients with HCM.

Methods

A thorough search was conducted in databases including PubMed, Embase, Cochrane Library, and Web of Science, encompassing literature from inception until June 2023. The primary endpoints examined were: (1) all-cause mortality; (2) an arrhythmic endpoint comprising sudden cardiac death (SCD), sustained ventricular tachycardia, ventricular fibrillation, or aborted SCD; and (3) a composite endpoint incorporating either (1) or (2), in addition to hospitalization for heart failure or cardiac transplantation. Pooled estimates were derived using a random-effects meta-analysis model.

Results

The analysis encompassed a total of 29 observational studies, involving 44,677 patients diagnosed with HCM, of which 16,807 were female. Baseline characteristics revealed that the female group exhibited an advanced age [55.66 ± 0.04 years vs. 50.38 ± 0.03 years, pooled mean difference (MD) = 0.31, 95% CI: 0.22-0.40, p = 0.000, I2 = 88.89%], a higher proportion of New York Heart Association class III/IV patients [pooled odds ratio (OR) = 1.94, 95% CI: 1.55-2.43, p = 0.000, I2 = 85.92%], and a greater prevalence of left ventricular outflow tract gradient greater than or equal to 30 mmHg (pooled OR = 1.48, 95% CI: 1.27-1.73, p = 0.000, I2 = 68.88%) compared to the male group. The female group were more likely to have a positive genetic test (pooled OR = 1.27, 95% CI: 1.08-1.48, p = 0.000, I2 = 42.74%) and to carry the myosin heavy chain beta 7 mutation (pooled OR = 1.26, 95% CI: 1.04-1.54, p = 0.020, I2 = 0.00%) compared to the male group. Female sex exhibited a significant association with increased risks of all-cause mortality (pooled OR = 1.62, 95% CI: 1.38-1.89, p = 0.000, I2 = 72.78%) and the composite endpoint (pooled OR = 1.47, 95% CI: 1.20-1.79, p = 0.000, I2 = 84.96%), while no substantial difference was observed in the arrhythmic endpoint (pooled OR = 1.08, 95% CI: 0.87-1.34, p = 0.490, I2 = 55.48%).

Conclusions

The present findings suggest that female patients with HCM tend to experience poorer clinical outcomes. It is imperative to critically reevaluate disease definitions and enhance awareness to mitigate delays in the diagnosis and treatment of HCM in women, thereby fostering equitable healthcare practices.

Systematic Review Registration

https://www.crd.york.ac.uk/, PROSPERO (CRD42023431881).

Outcomes of Alcohol Septal Ablation in Patients With Severe Left Ventricular Outflow Tract Obstruction: A Propensity Score Matching Analysis

BACKGROUND

The current ACC/AHA guidelines on hypertrophic cardiomyopathy (HCM) caution that alcohol septal ablation (ASA) might be less effective in patients with left ventricular outflow tract obstruction (LVOTO) ≥ 100 mm Hg.

METHODS

We used a multinational registry to evaluate the outcome of ASA patients according to baseline LVOTO.

RESULTS

A total of 1346 ASA patients were enrolled and followed for 5.8 ± 4.7 years (7764 patient-years). The patients with baseline LVOTO ≥ 100 mm Hg were significantly older (61 ± 14 years vs 57 ± 13 years; P < 0.01), more often women (60% vs 45%; P < 0.01), and had a more pronounced HCM phenotype than those with baseline LVOTO < 100 mm Hg. There were no significant differences in the occurrences of 30-day major cardiovascular adverse events in the 2 groups. After propensity score matching (2 groups, 257 pairs of patients), the long-term survival was similar in both groups (P = 0.10), the relative reduction of LVOTO was higher in the group with baseline LVOTO ≥ 100 mm Hg (82 ± 21% vs 73 ± 26%; P < 0.01), but the residual resting LVOTO remained higher in this group (23 ± 29 mm Hg vs 13 ± 13 mm Hg; P < 0.01). Dyspnoea (NYHA functional class) at the most recent clinical check-up was similar in the 2 groups (1.7 ± 0.7 vs 1.7 ± 0.7; P = 0.85), and patients with baseline LVOTO ≥ 100 mm Hg underwent more reinterventions (P = 0.02).

CONCLUSIONS

After propensity matching, ASA patients with baseline LVOTO ≥ 100 mm Hg had similar survival and dyspnoea as patients with baseline LVOTO < 100 mm Hg, but their residual LVOTO and risk of repeated procedures were higher.

Mavacamten in Patients With Hypertrophic Cardiomyopathy Referred for Septal Reduction: Week 56 Results From the VALOR-HCM Randomized Clinical Trial

Importance

There is an unmet need for novel medical therapies before recommending invasive therapies for patients with severely symptomatic obstructive hypertrophic cardiomyopathy (HCM). Mavacamten has been shown to improve left ventricular outflow tract (LVOT) gradient and symptoms and may thus reduce the short-term need for septal reduction therapy (SRT).

Objective

To examine the cumulative longer-term effect of mavacamten on the need for SRT through week 56.

Design, Setting, and Participants

This was a double-blind, placebo-controlled, multicenter, randomized clinical trial with placebo crossover at 16 weeks, conducted from July 2020 to November 2022. Participants were recruited from 19 US HCM centers. Included in the trial were patients with obstructive HCM (New York Heart Association class III/IV) referred for SRT. Study data were analyzed April to August 2023.

Interventions

Patients initially assigned to mavacamten at baseline continued the drug for 56 weeks, and patients taking placebo crossed over to mavacamten from week 16 to week 56 (40-week exposure). Dose titrations were performed using echocardiographic LVOT gradient and LV ejection fraction (LVEF) measurements.

Main Outcome and Measure

Proportion of patients undergoing SRT, remaining guideline eligible or unevaluable SRT status at week 56.

Results

Of 112 patients with highly symptomatic obstructive HCM, 108 (mean [SD] age, 60.3 [12.5] years; 54 male [50.0%]) qualified for the week 56 evaluation. At week 56, 5 of 56 patients (8.9%) in the original mavacamten group (3 underwent SRT, 1 was SRT eligible, and 1 was not SRT evaluable) and 10 of 52 patients (19.2%) in the placebo crossover group (3 underwent SRT, 4 were SRT eligible, and 3 were not SRT evaluable) met the composite end point. A total of 96 of 108 patients (89%) continued mavacamten long term. Between the mavacamten and placebo-to-mavacamten groups, respectively, after 56 weeks, there was a sustained reduction in resting (mean difference, -34.0 mm Hg; 95% CI, -43.5 to -24.5 mm Hg and -33.2 mm Hg; 95% CI, -41.9 to -24.5 mm Hg) and Valsalva (mean difference, -45.6 mm Hg; 95% CI, -56.5 to -34.6 mm Hg and -54.6 mm Hg; 95% CI, -66.0 to -43.3 mm Hg) LVOT gradients. Similarly, there was an improvement in NYHA class of 1 or higher in 51 of 55 patients (93%) in the original mavacamten group and in 37 of 51 patients (73%) in the placebo crossover group. Overall, 12 of 108 patients (11.1%; 95% CI, 5.87%-18.60%), which represents 7 of 56 patients (12.5%) in the original mavacamten group and 5 of 52 patients (9.6%) in the placebo crossover group, had an LVEF less than 50% (2 with LVEF ≤30%, one of whom died), and 9 of 12 patients (75%) continued treatment.

Conclusions and Relevance

Results of this randomized clinical trial showed that in patients with symptomatic obstructive HCM, mavacamten reduced the need for SRT at week 56, with sustained improvements in LVOT gradients and symptoms. Although this represents a useful therapeutic option, given the potential risk of LV systolic dysfunction, there is a continued need for close monitoring.

Trial Registration

ClinicalTrials.gov Identifier: NCT04349072.

Unmet needs and future directions in hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is a highly treatable monogenetic disorder affecting nearly 0.2% of the population. The high burden of this disease demands suitable measures for early diagnosis and preventing as well as tackling misdiagnosis. While conventionally available therapies have been efficacious in reducing symptoms, they have not been able to change the natural history of the disease. The landscape of medical treatment is rapidly changing with advent of novel pharmacotherapies such as cardiac myosin inhibitors. Ongoing investigations in gene editing have demonstrated benefits in correcting underlying genetic mutations and this is where the future of treatment lies. Contemporary procedural techniques as alternatives to available septal reduction therapies independent of coronary vascular anatomy are also emerging. This review details the recent developments, unmet needs and future directions in diagnosis, medical and invasive treatment of HCM.

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.

Patient reported outcomes in obstructive hypertrophic cardiomyopathy undergoing myectomy: Results from SPIRIT-HCM study

BACKGROUND

Patient reported outcomes (PRO) can assess quality of life (QOL) in obstructive hypertrophic cardiomyopathy (oHCM). In symptomatic oHCM patients, we sought to study the correlation between various PROs, their association with physician reported New York Heart Association (NYHA) class and changes after surgical myectomy.

METHODS

We prospectively studied 173 symptomatic oHCM patients undergoing myectomy (age 51 years, 62% men) between 3/17-6/20. PROs, including a) Kansas City Cardiomyopathy Questionnaire (KCCQ) summary score b) Patient-Reported Outcomes Measurement Information System [PROMIS] c) Duke Activity Status Index [DASI] & d) European QOL score [EQ-5D], along with NYHA class, 6-min walk test (6MWT) distance and peak left ventricular outflow tract gradient (PLVOTG) were recorded at baseline and 12 month follow-up.

RESULTS

The median baseline PRO scores (KCCQ summary, PROMIS physical, PROMIS mental, DASI, EQ-5D) were 50, 67, 63, 25, 50, 37, 44, 25 and 0.61, respectively; 6MWT distance was 366 m. There were significant correlations between various PROs (r-values between 0.66 and 0.92, p < 0.001), but only modest correlations with 6MWT and provokable LVOTG (r-values between 0.2 and 0.5, p < 0.01). At baseline, 35-49% patients in NYHA class II had PROs worse than median, while 30-39% patients in NYHA Class III/IV had PROs better than median. At follow-up, a 20 point improvement in KCCQ summary score was observed in 80%, 4 point improvement in DASI score in 83%, 4 point improvement in PROMIS physical score 86% and a 0.04 point improvement in EQ-5D in 85%); along with improvements in NYHA class (67% in Class I) and peak LVOTG (median 13 mmHg) and 6MWT (median distance 438 m).

CONCLUSIONS

In a prospective study of symptomatic oHCM patients, surgical myectomy significantly improved PROs, LVOT obstruction, and functional capacity, with a high correlation between various PROs. However, there was high rate of discordance between PROs and NYHA class.

STUDY REGISTRATION

ClinicalTrials.gov: NCT03092843.

Volume-outcome relationship in septal myectomy for hypertrophic obstructive cardiomyopathy

BACKGROUND

Septal myectomy is the gold standard treatment for refractory hypertrophic obstructive cardiomyopathy. The present study characterized the association of septal myectomy volume and cardiac surgery volume with outcomes after septal myectomy.

METHODS

Adults undergoing septal myectomy for hypertrophic obstructive cardiomyopathy were identified in the 2016 to 2019 Nationwide Readmissions Database. Centers were grouped into low-, medium-, and high-volume hospitals by tertiles based on institutional septal myectomy caseload. Overall cardiac surgery volume was similarly assessed. Generalized linear models were used to test the association between hospital septal myectomy or cardiac surgery volume and in-hospital mortality, mitral valve repair, and 90-day non-elective readmission.

RESULTS

Of 3,337 patients, 30.8% underwent septal myectomy at high-volume hospitals, whereas 39.1% were managed at low-volume hospitals. Patients at high-volume hospitals had a similar burden of comorbidities at low-volume hospitals, although congestive heart failure was more prevalent at high-volume hospitals. Despite comparable rates of mitral regurgitation, patients more commonly avoided mitral valve intervention at high-volume hospitals compared with low-volume hospitals (72.9% vs 68.3%; P = .007). After risk adjustment, high-volume hospital status was associated with reduced odds of mortality (0.24; 95% CI, 0.08-0.77) and readmission (0.59; 95% CI, 0.3-0.97). Among cases requiring mitral intervention, high-volume hospital status was associated with greater odds of valve repair (5.33; 95% CI, 2.54-11.13) relative to low-volume hospitals. Overall cardiac surgery volume was not associated with any studied outcome.

CONCLUSION

Greater septal myectomy volume, but not overall cardiac surgery volume, was associated with reduced mortality and greater mitral valve repair relative to replacement after septal myectomy. These findings suggest that septal myectomy for hypertrophic obstructive cardiomyopathy should be performed at centers with expertise in this operation.

Dose-Blinded Myosin Inhibition in Patients With Obstructive Hypertrophic Cardiomyopathy Referred for Septal Reduction Therapy: Outcomes Through 32 Weeks

BACKGROUND

Septal reduction therapy (SRT) in patients with intractable symptoms from obstructive hypertrophic cardiomyopathy (oHCM) is associated with variable morbidity and mortality. The VALOR-HCM trial (A Study to Evaluate Mavacamten in Adults with Symptomatic Obstructive Hypertrophic Cardiomyopathy Who Are Eligible for Septal Reduction Therapy) examined the effect of mavacamten on the need for SRT through week 32 in oHCM.

METHODS

A double-blind randomized placebo-controlled multicenter trial at 19 US sites included patients with oHCM on maximal tolerated medical therapy referred for SRT with left ventricular outflow tract gradient ≥50 mm Hg at rest or provocation (enrollment, July 2020-October 2021). The group initially randomized to mavacamten continued the drug for 32 weeks, and the placebo group crossed over to dose-blinded mavacamten from week 16 to week 32. Dose titrations were based on investigator-blinded echocardiographic assessment of left ventricular outflow tract gradient and left ventricular ejection fraction. The principal end point was the proportion of patients proceeding with SRT or remaining guideline eligible at 32 weeks in both treatment groups.

RESULTS

From the 112 randomized patients with oHCM, 108 (mean age, 60.3 years; 50% men; 94% in New York Heart Association class III/IV) qualified for week 32 evaluation (56 in the original mavacamten group and 52 in the placebo cross-over group). After 32 weeks, 6 of 56 patients (10.7%) in the original mavacamten group and 7 of 52 patients (13.5%) in the placebo cross-over group met SRT guideline criteria or elected to undergo SRT. After 32 weeks, a sustained reduction in resting left ventricular outflow tract gradient (-33.0 mm Hg [95% CI, -41.1 to -24.9]) and Valsalva left ventricular outflow tract gradient (-43.0 mm Hg [95% CI, -52.1 to -33.9]) was observed in the original mavacamten group. A similar reduction in resting (-33.7 mm Hg [95% CI, -42.2 to -25.2]) and Valsalva (-52.9 mm Hg [95% CI, -63.2 to -42.6]) gradients was quantified in the cross-over group after 16 weeks of mavacamten. After 32 weeks, improvement by ≥1 New York Heart Association class was observed in 48 of 53 patients (90.6%) in the original mavacamten group and 35 of 50 patients (70%) after 16 weeks in the cross-over group.

CONCLUSIONS

In severely symptomatic patients with oHCM, 32 weeks of mavacamten treatment showed sustained reduction in the proportion proceeding to SRT or remaining guideline eligible, with similar effects observed in patients who crossed over from placebo after 16 weeks.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: NCT04349072.

Cardiac Resynchronization Therapy and Hypertrophic Cardiomyopathy: A Comprehensive Review

Hypertrophic cardiomyopathy (HCM) is an inherited primary myocardial disease characterized by asymmetrical/symmetrical left ventricle (LV) hypertrophy, with or without LV outflow tract (LVOT) dynamic obstruction, and poor prognosis. Cardiac resynchronization therapy (CRT) has emerged as a minimally invasive tool for patients with heart failure (HF) with decreased LV ejection fraction (LVEF) and prolonged QRS duration of over 120 ms with or without left bundle branch block (LBBB). Several HCM patients are at risk of developing LBBB because of disease progression or secondary to septal myomectomy, while others might develop HF with decreased LVEF, alleged end-stage/dilated HCM, especially those with thin myofilament mutations. Several studies have shown that patients with myectomy-induced LBBB might benefit from left bundle branch pacing or CRT to relieve symptoms, improve exercise capacity, and increase LVEF. Otherwise, patients with end-stage/dilated HCM and prolonged QRS interval could gain from CRT in terms of NYHA class improvement, LV systolic performance increase and, to some degree, LV reverse remodeling. Moreover, several electrical and imaging parameters might aid proper selection and stratification of HCM patients to benefit from CRT. Nonetheless, current available data are scarce and further studies are still required to accurately clarify the view. This review reassesses the importance of CRT in patients with HCM based on current research by contrasting and contextualizing data from various published studies.

Survival After Septal Reduction in Patients >65 Years Old With Obstructive Hypertrophic Cardiomyopathy

BACKGROUND

Obstructive hypertrophic cardiomyopathy (oHCM) is increasingly being diagnosed in elderly patients.

OBJECTIVES

The authors sought to study long-term outcomes of septal reduction therapies (SRT) in Medicare patients with oHCM, and hospital volume-outcome relation.

METHODS

Medicare beneficiaries aged >65 years who underwent SRT, septal myectomy (SM) or alcohol septal ablation (ASA), from 2013 through 2019 were identified. Primary outcome was all-cause mortality, and secondary outcomes included heart failure (HF) readmission and need for redo SRT in follow-up. Overlap propensity score weighting was used to adjust for differences between both groups. Relation between hospital SRT volume and short-term and long-term mortality was studied.

RESULTS

The study included 5,679 oHCM patients (SM = 3,680 and ASA = 1,999, mean age 72.9 vs 74.8 years, women 67.2% vs 71.1%; P < 0.01). SM patients had fewer comorbidities, but after adjustment, both groups were well balanced. At 4 years (IQR: 2-6 years), although there was no difference in long-term mortality between SM and ASA (HR: 0.87; 95% CI: 0.74-1.03; P = 0.1), on landmark analysis, SM was associated with lower mortality after 2 years of follow-up (HR: 0.72; 95% CI: 0.60-0.87; P < 0.001) and had lower need for redo SRT. Both reduced HF readmissions in follow-up vs 1 year pre-SRT. Higher-volume centers had better outcomes vs lower-volume centers, but 70% of SRT were performed in low-volume centers.

CONCLUSIONS

SRT reduced HF readmission in Medicare patients with oHCM. SM is associated with lower redo and better long-term survival compared with ASA. Despite better outcomes in high-volume centers, 70% of SRT are performed in low-volume U.S. centers.

Midterm results of latent outflow tract obstruction in hypertrophic cardiomyopathy after septal myectomy: A propensity score-matched study

BACKGROUND AND AIM OF THE STUDY

The midterm clinical outcomes of patients with latent left ventricular outflow tract (LVOT) obstruction who undergo septal myectomy are unclear. Therefore, this study aimed to evaluate the clinical outcomes of patients with latent LVOT obstruction who underwent septal myectomy.

METHODS

We studied 34 patients with hypertrophic cardiomyopathy (HCM) and latent LVOT obstruction who underwent septal myectomy in 2011-2019 at Anzhen Hospital. After 2:1 propensity score matching, the study cohort included 34 patients with latent LVOT obstruction and 68 patients with resting LVOT obstruction.

RESULTS

Compared to patients with resting LVOT obstruction, patients with latent LVOT obstruction had a thinner interventricular septal thickness (18.2 ± 3.2 mm vs. 20.4 ± 5.6 mm; p = .01), while the proportion of moderate or severe mitral regurgitation was significantly higher (26.5% vs. 5.9%; p = .003). Moreover, the proportion of mitral valve procedures (26.5% vs. 5.9%; p = .004) was significantly higher in patients with latent LVOT obstruction. However, there was no intergroup difference in cardiovascular death (5.9% vs. 1.5%, p = .26). Furthermore, the 5-year survival rates after sudden cardiac death (100.0% vs. 91.7%; p = .26) and cardiovascular death (95.5% vs. 89.0%; p = .32) were similar between HCM patients with latent versus resting LVOT obstruction.

CONCLUSIONS

Midterm clinical outcomes were similar and excellent in a matched cohort of HCM patients with latent versus resting LVOT obstruction after septal myectomy.

Posterior Wall Thickness Associates With Survival Following Septal Myectomy for Obstructive Hypertrophic Cardiomyopathy

BACKGROUND

The left ventricular (LV) posterior wall thickness (PWT) is a predictor of sudden cardiac death in pediatric patients with hypertrophic cardiomyopathy (HCM), but the prognostic importance of PWT in adults has not been examined.

OBJECTIVES

The goal of this study was to evaluate the association of LV PWT with late survival in adult patients undergoing septal myectomy for obstructive HCM.

METHODS

This single-center study reviewed 2,418 patients who underwent transaortic septal myectomy for obstructive HCM.

RESULTS

The median preoperative PWT was 13 (IQR: 11-15) mm. Patients with PWT >13 mm tended to have systemic hypertension (55.4% vs 49.1%; P = 0.002) and a larger body mass index (median: 30.8 [IQR: 27.1-35.1] kg/m² vs 29.6 [IQR: 26.1-33.9] kg/m²; P < 0.001). Preoperatively, PWT >13 mm was associated with increased septal thickness (median: 21 [IQR: 18-24] mm vs 19 [IQR: 17-22] mm; P < 0.001), greater maximum instantaneous left ventricular outflow tract (LVOT) gradient at rest (median: 67 [IQR: 36-96] mm Hg vs 47 [IQR: 19-79] mm Hg), and increased likelihood of moderate or greater mitral valve regurgitation (54.3% vs 47.3%; P = 0.001). However, PWT was not related to the severity of limitations measured by New York Heart Association functional class (P = 0.674). After adjusting for baseline covariates, greater PWT was an independent risk factor for late mortality after septal myectomy (P = 0.003).

CONCLUSIONS

PWT is a newly identified predictor of reduced long-term survival after septal myectomy that is independent of septal thickness and severity of LVOT gradient. Future studies are warranted to investigate the mechanisms underlying the association and the potential usefulness of PWT in patient management.

Left ventricular remodeling following septal myectomy in hypertrophic obstructive cardiomyopathy

Objectives

The purpose of this study is to determine whether or not left ventricular remodeling can be induced after septal myectomy in patients with obstructive hypertrophic cardiomyopathy, and if so, how it occurs, using gated cardiac computed tomography.

Methods

Fifty patients with hypertrophic obstructive cardiomyopathy who underwent septal myectomy along the septal band between March 2016 and July 2020 were retrospectively reviewed. Recent consecutive 19 patients underwent postoperative cardiac computed tomography. In these patients, volumes of the septal band and thickness of 17 left ventricular myocardial segments were measured to determine the changes after surgery.

Results

The resection volume predicted by preoperative computed tomography and the actual resection volume were 6.7 ± 3.3 mL and 6.4 ± 2.7 mL. In-hospital mortality was 0%. Moderate or greater mitral valve regurgitation and systolic anterior motion decreased from 56% to 6% and 86% to 6%, respectively. Median preoperative ventricular septal thickness and left ventricular outflow tract pressure gradient at rest decreased from 20.0 mm (interquartile range, 17.0-24.0 mm) and 74.0 mm Hg (interquartile range, 42.5-92.5 mm Hg) to 14.0 mm (interquartile range, 11.5-16.0 mm) and 15.5 mm Hg (interquartile range, 12.1-21.5 mm Hg), respectively. Postoperative computed tomography confirmed a reduction in septal band volume of 5.7 ± 2.8 mL. Total left ventricular myocardial volume was reduced by 12.9 ± 8.8 mL, which exceeded the volume reduction of the resected septal band. All segments except the basal inferior and basal inferolateral regions showed a significant decrease in wall thickness by a median of 6.4%.

Conclusions

Properly performed septal myectomy may induce remodeling of the entire left ventricle, not just the resected area.

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 strong negative inotropic drugs potentially useful for symptom management.

Prognostic value of age-sex adjusted NT-proBNP ratio in obstructive hypertrophic cardiomyopathy

BACKGROUND

We sought to determine the incremental prognostic value of age-sex adjusted N-terminal prohormone brain natriuretic peptide (NT-pro BNP) ratio in obstructive hypertrophic cardiomyopathy (oHCM) patients.

METHODS

The study included 2119 consecutive oHCM patients (age 55 ± 13 years, 53% men, maximal LVOT ≥30 mmHg) evaluated between 6/2002-12/2018 with BNP or NT-pro BNP measured at baseline. NT-pro BNP ratio was calculated as: NT-proBNP/ upper limit of normal NT-proBNP derived from age-sex matched controls. Septal reduction therapy (SRT) during follow-up was recorded. Primary endpoint was death, need for cardiac transplantation or appropriate internal cardioverter defibrillator (ICD) discharge.

RESULTS

Median NT-proBNP ratio was 5.4 (IQR 2.1-12.3). Using spline analysis, log-transformed NT-pro BNP ratio of 2 (corresponding to NT-pro BNP ratio of 6) was the optimal value where primary endpoint hazards crossed 1; there were 966 patients with high and 1153 patients with low NT-pro BNP ratio. 1665 (79%) patients underwent SRT at 47 days (IQR 7-128 days). At 5.4 years of follow-up (IQR 2.8-9.2 years), the primary outcome occurred in 315 (15%) patients (deaths = 270). High NT-pro BNP ratio was associated with higher risk of primary outcome in unadjusted (30.1 vs. 17.2 events/1000 person-year, hazard ratio or (HR) 1.73, 1.37-2.17, P < 0.001) and adjusted analysis (aHR 1.69, 95% 1.19-2.38, P = 0.003) vs. low NT-pro BNP ratio. Even in asymptomatic patients, NT-pro BNP ratio remained associated with primary outcome (aHR 1.28, 95% CI 1.06-1.54, P = 0.01).

CONCLUSIONS

Age-sex adjusted NT-pro BNP ratio is independently associated with long-term outcomes in oHCM patients, including in a subgroup of asymptomatic patients.

Comparison of Right Anterior Mini-Thoracotomy Versus Partial Upper Sternotomy in Aortic Valve Replacement

Introduction

Propensity score analysis of midterm outcomes after isolated aortic valve replacement through right anterior mini-thoracotomy and partial upper sternotomy could provide information about the most beneficial minimally invasive technique for the patient based on the preoperative risk factors.

Methods

Between March 2015 and February 2021, 694 minimally invasive isolated aortic valve surgeries were performed at our institution. Among these, 441 right anterior mini-thoracotomies and 253 partial upper sternotomies were performed. A propensity score analysis was performed in 202 matched pairs.

Results

Cardiopulmonary bypass time and cross-clamp time were significantly shorter in the right anterior mini-thoracotomy group than in the partial upper sternotomy group (p = 0.001 and p < 0.001, respectively). Time to first mobilization and hospital stay were significantly shorter in the right anterior mini-thoracotomy group than in the partial upper sternotomy group (p = 0.005, p = 0.001, respectively). A significantly lower incidence of revision surgery was noted in the right anterior mini-thoracotomy group than in the partial upper sternotomy group (p = 0.046). No significant differences in 30-day mortality (p = 1.000) and 1-year mortality (p = 0.543) were noted. Kaplan-Meier survival estimates were 96.3% in the right anterior mini-thoracotomy group and 92.7% in the partial upper sternotomy group after 4 years (log rank 0.169), respectively.

Conclusions

Despite the technical challenges, right anterior mini-thoracotomy can be chosen as first-line strategy for isolated aortic valve replacement. For patients unsuitable for this technique, the partial upper sternotomy remains a safe method that can be performed by a wide range of surgeons.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12325-022-02263-6.

Sex-related differences in left ventricular remodeling and outcome after alcohol septal ablation in hypertrophic obstructive cardiomyopathy: insights from cardiovascular magnetic resonance imaging

Background

Alcohol septal ablation (ASA) has been proven to reverse left ventricular (LV) remodeling in hypertrophic cardiomyopathy (HCM). However, there are no studies on the effect of sex on LV remodeling after ASA. We aimed to investigate whether sex differences affect the process of LV remodeling and outcome after ASA.

Methods

A total of 107 patients with obstructive HCM (54 men and 53 women, mean age 51 ± 8 years) were recruited. Cardiovascular magnetic resonance (CMR) was performed at baseline and 16 months after ASA. The extent of late gadolinium enhancement (LGE) was measured.

Results

Women had a higher indexed LV mass and smaller indexed LV end-systolic volumes than men at the time of ASA. After ASA, both men and women exhibited a regression of LV mass, and the percentage of mass regression was greater in men than women (15.3% ± 4.3% vs. 10.7% ± 1.8%, p < 0.001). In multivariable analysis, male sex, higher reduction of LV outflow tract (LVOT) gradient and lower baseline LV mass index were independently associated with greater LV mass regression after ASA. Kaplan–Meier analysis showed significantly higher cardiovascular events in women than in men (p = 0.015). Female sex [hazard ratio (HR) 3.913, p = 0.038] and LV mass preablation (HR, 1.019, p = 0.010) were independent predictors of cardiovascular outcomes.

Conclusions

Males with HCM had favorable reverse remodeling with greater LV mass regression post-ASA than female patients. This favorable LV reverse remodeling might provide a mechanistic explanation for the survival advantage in men.

Female patients with HCM showed worse LV remodeling with a higher indexed LV mass and a smaller indexed LV end-diastolic volume (measured by CMR) at the time of ASA.

Both men and women exhibited the LV reverse remodeling, however, men experienced more favorable LV reverse remodeling than women after ASA. The overall percentage of the LVM index regression was greater among men than women.

Women with HCM had worse relative composite endpoint than men. Sex and LV mass preablation were independent predictors of cardiovascular outcomes.

Sex appears to be a significant modifier in HCM patients receiving ASA treatment and highlighted the need for a different approach to women with HCM, such as improving women’s awareness of diagnosis and follow-up management as well as earlier referral for advanced therapies (e.g., septal reduction therapy and ICD implantation).

Clinical Characteristics and Healthcare Resource Utilization among Patients with Obstructive Hypertrophic Cardiomyopathy Treated in a Range of Settings in the United States

Obstructive hypertrophic cardiomyopathy (oHCM) has been studied primarily in comprehensive centers of excellence. Broadening the understanding of patients with oHCM in the general population may improve identification and treatment in other settings. This retrospective cohort study identified adults with oHCM from a large electronic medical record database comprising data from 39 integrated delivery networks (IBM Explorys; observational period: January 2009–July 2019). Clinical characteristics, healthcare resource utilization (HCRU), and outcomes were reported. Of 8791 patients, 53.0% were female and the mean index age was 61.8 years. Cardiovascular drugs prescribed included beta-blockers (80.5%), calcium channel blockers (46.0%), and disopyramide (2.4%). Over time, heart failure, atrial fibrillation, and ventricular arrhythmias increased. Surgical procedures included septal myectomy (22.0%), alcohol septal ablation (0.6%), and heart transplantation (0.3%). Implantable cardioverter defibrillators were present in 11.2% of patients. After initial septal reduction therapy (SRT), HCRU increased and 550 patients (27.7%) required a reintervention. Of the overall group, 2.7% experienced sudden cardiac arrest by end of study. In conclusion, this cohort of patients with oHCM had guideline-recommended drug therapy and procedures. Despite this, heart failure, atrial fibrillation, and ventricular arrhythmias increased, and more than a quarter of patients undergoing SRT required reintervention. These unresolved issues emphasize the unmet need for new, effective therapies for patients with oHCM.

Myosin Inhibition in Patients With Obstructive Hypertrophic Cardiomyopathy Referred for Septal Reduction Therapy

BACKGROUND

Septal reduction therapy (SRT), surgical myectomy or alcohol ablation, is recommended for obstructive hypertrophic cardiomyopathy (oHCM) patients with intractable symptoms despite maximal medical therapy, but is associated with morbidity and mortality.

OBJECTIVES

This study sought to determine whether the oral myosin inhibitor mavacamten enables patients to improve sufficiently to no longer meet guideline criteria or choose to not undergo SRT.

METHODS

Patients with left ventricular (LV) outflow tract (LVOT) gradient ≥50 mm Hg at rest/provocation who met guideline criteria for SRT were randomized, double blind, to mavacamten, 5 mg daily, or placebo, titrated up to 15 mg based on LVOT gradient and LV ejection fraction. The primary endpoint was the composite of the proportion of patients proceeding with SRT or who remained guideline-eligible after 16 weeks' treatment.

RESULTS

One hundred and twelve oHCM patients were enrolled, mean age 60 ± 12 years, 51% men, 93% New York Heart Association (NYHA) functional class III/IV, with a mean post-exercise LVOT gradient of 84 ± 35.8 mm Hg. After 16 weeks, 43 of 56 placebo patients (76.8%) and 10 of 56 mavacamten patients (17.9%) met guideline criteria or underwent SRT, difference (58.9%; 95% CI: 44.0%-73.9%; P < 0.001). Hierarchical testing of secondary outcomes showed significant differences (P < 0.001) favoring mavacamten, mean differences in post-exercise peak LVOT gradient -37.2 mm Hg; ≥1 NYHA functional class improvement 41.1%; improvement in patient-reported outcome 9.4 points; and NT-proBNP and cardiac troponin I between-groups geometric mean ratio 0.33 and 0.53.

CONCLUSIONS

In oHCM patients with intractable symptoms, mavacamten significantly reduced the fraction of patients meeting guideline criteria for SRT after 16 weeks. Long-term freedom from SRT remains to be determined. (A Study to Evaluate Mavacamten in Adults With Symptomatic Obstructive HCM Who Are Eligible for Septal Reduction Therapy [VALOR-HCM]; NCT04349072).

Review of Contemporary Invasive Treatment Approaches and Critical Appraisal of Guidelines on Hypertrophic Obstructive Cardiomyopathy: State-of-the-Art Review

BACKGROUND

Hypertrophic obstructive cardiomyopathy (HOCM) is a heterogeneous disease with different clinical presentations, albeit producing similar dismal long-term outcomes if left untreated. Several approaches are available for the treatment of HOCM; e.g., alcohol septal ablation (ASA) and surgical myectomy (SM). The objectives of the current review were to (1) discuss the place of the standard invasive treatment modalities (ASA and SM) for HOCM; (2) summarize and compare novel techniques for the management of HOCM; (3) analyze current guidelines addressing HOCM management; and (4) offer suggestions for the treatment of complex HOCM presentations.

METHODS

We searched the literature and attempted to gather the most relevant and impactful available evidence on ASA, SM, and other invasive means of treatment of HOCM. The literature search yielded thousands of results, and 103 significant publications were ultimately included.

RESULTS

We critically analyzed available guidelines and provided context in the setting of patient selection for standard and novel treatment modalities. This review offers the most comprehensive analysis to-date of available invasive treatments for HOCM. These include the standard treatments, SM and ASA, as well as novel treatments such as dual-chamber pacing and radiofrequency catheter ablation. We also account for complex pathoanatomic presentations and current guidelines to offer suggestions for tailored care of patients with HOCM. Finally, we consider promising future therapies for HOCM.

CONCLUSIONS

HOCM is a heterogeneous disease associated with poor outcomes if left untreated. Several strategies for treatment of HOCM are available but patient selection for the procedure is crucial.

Recommendations for Multimodality Cardiovascular Imaging of Patients with Hypertrophic Cardiomyopathy: An Update from the American Society of Echocardiography, in Collaboration with the American Society of Nuclear Cardiology, the Society for Cardiovascular Magnetic Resonance, and the Society of Cardiovascular Computed Tomography

Hypertrophic cardiomyopathy (HCM) is defined by the presence of left ventricular hypertrophy in the absence of other potentially causative cardiac, systemic, syndromic, or metabolic diseases. Symptoms can be related to a range of pathophysiologic mechanisms including left ventricular outflow tract obstruction with or without significant mitral regurgitation, diastolic dysfunction with heart failure with preserved and heart failure with reduced ejection fraction, autonomic dysfunction, ischemia, and arrhythmias. Appropriate understanding and utilization of multimodality imaging is fundamental to accurate diagnosis as well as longitudinal care of patients with HCM. Resting and stress imaging provide comprehensive and complementary information to help clarify mechanism(s) responsible for symptoms such that appropriate and timely treatment strategies may be implemented. Advanced imaging is relied upon to guide certain treatment options including septal reduction therapy and mitral valve repair. Using both clinical and imaging parameters, enhanced algorithms for sudden cardiac death risk stratification facilitate selection of HCM patients most likely to benefit from implantable cardioverter-defibrillators.

Transaortic Shallow Septal Myectomy and Cutting of Secondary Fibrotic Mitral Valve Chordae—A 5-Year Single-Center Experience in the Treatment of Hypertrophic Obstructive Cardiomyopathy

Background: Anomalies of the mitral apparatus have been shown to contribute to left ventricular outflow obstruction in patients with hypertrophic cardiomyopathy (HCM). We report our 5-year single-center experience with a shallow myectomy procedure associated with transaortic mitral valve repair in a cohort of HCM patients. Methods: We studied 83 consecutive patients who underwent surgical treatment of symptomatic left ventricular outflow obstruction. In all study patients, a transaortic shallow septal myectomy was performed. Fibrous or muscular structures connecting the papillary muscles to the septum or free wall were resected, and fibrotic secondary chordae of the anterior mitral valve were cut selectively. Results: We report one death (1.2%) during hospitalization, no iatrogenic ventricular septal defects, and two (2.4%) mitral valve replacements. At discharge, no patients were in New York Heart Association (NYHA) Class III/IV, from 49 (59%) preoperatively. Mean maximal septal thickness decreased from 24 ± 6 to 16 ± 3 mm. Mean outflow gradient decreased from 93 ± 33 to 13 ± 11 mmHg. Grade 3 or 4 mitral regurgitation was noticed in one patient postoperatively, from 32 (39%) before surgery. Conclusions: Shallow septal myectomy associated with secondary mitral valve chordal cutting and papillary muscle mobilization provided excellent results offering adequate treatment of outflow obstruction.

Transmitral Septal Myectomy and Mitral Valve Surgery via Right Mini-Thoracotomy

Background Transmitral myectomy for symptomatic hypertrophic obstructive cardiomyopathy is possible with existence of substantial mitral valve disease. We present herein our experience of minimally invasive transmitral septal myectomy combined with mitral valve surgery through right anterior mini-thoracotomy in the past 4 years at our institution.

Methods Between March 2017 and October 2020, 14 patients with hypertrophic obstructive cardiomyopathy and mitral valve disease required minimally invasive transmitral septal myectomy combined with mitral valve reconstruction or replacement at our institution. Mean age of patients was 54.2 ± 11.4 and 42.9% (n = 6) were female. Twelve patients (85.1%) were in New York Heart Association class III to IV and 6 patients (42.9%) presented with persistent atrial fibrillation. Clinical data were prospectively entered into our institutional database.

Results Cardiopulmonary bypass time accounted for 140.2 ± 32.6 minutes and the myocardial ischemic time was 78.5 ± 12.4 minutes. Thirty-day mortality and overall mortality were zero. Peak ventricular outflow gradient decreased from 75.2 ± 12.7 to 9.4 ± 2.3 mm Hg (p < 0.0001). Simultaneously, mitral valve reconstruction and replacement were performed in 11 (78.6%) and 3 (21.4%) patients, respectively. No systolic anterior motion was seen in patients with mitral valve repair. No conversion to full sternotomy and/or rethoracotomy was noted. During a mean follow-up period of 24 ± 13 months, no patient required reoperation, no recurrence mitral regurgitation, and left ventricular outflow tract obstruction.

Conclusion Transmitral septal myectomy combined with mitral valve surgery through right anterior mini-thoracotomy can be performed safely with excellent surgical outcomes.

Midterm Outcome After Septal Myectomy and Medical Therapy in Mildly Symptomatic Patients With Hypertrophic Obstructive Cardiomyopathy

Objective

The purpose of this study was mainly to determine the midterm outcome of septal myectomy (SM) and medical therapy (MT) in mildly symptomatic patients (NYHA class II) with hypertrophic obstructive cardiomyopathy (HOCM).

Methods

The study cohort consisted of 184 mildly symptomatic patients with HOCM evaluated in Beijing Anzhen Hospital, Capital Medical University between March 2001 and December 2017, including 82 patients in the SM group and 102 patients in the MT group. Overall survival and HCM-related survival were mainly observed.

Results

The average follow-up time was 5.0 years. Compared to patients accepting MT, patients treated with SM were associated with comparable overall survival (96.5% and 93.1% vs. 92.9% and 83.0% at 5 and 10 years, respectively; P = 0.197) and HCM-related survival (98.7% and 98.7% vs. 94.2% and 86.1% at 5 and 10 years, respectively; P = 0.063). However, compared to MT, SM was superior at improvement of NYHA class (1.3 ± 0.6 vs. 2.1 ± 0.5, P &lt; 0.001) and mean reduction of resting left ventricular outflow (LVOT) gradient (78.5 ± 18.6% vs. 28.3 ± 18.4%, P &lt; 0.001). Multivariate analysis suggested that resting LVOT gradient in the last clinical examination was an independent predictor of all-cause mortality (HR = 1.017, 95%CI: 1.000–1.034, P = 0.045) and HCM-related mortality (HR = 1.024, 95%CI: 1.005–1.043, P = 0.012) in the entire cohort.

Conclusion

Compared with MT, SM had comparable overall survival and HCM-related survival in mildly symptomatic HOCM patients, but SM had advantages on improving clinical symptoms and reducing resting LVOT gradient. Resting LVOT gradient in the last clinical examination was an independent predictor of all-cause mortality and HCM-related mortality.

Outcomes Over Follow-up ≥10 Years After Surgical Myectomy for Symptomatic Obstructive Hypertrophic Cardiomyopathy

For over 50 years, surgical septal myectomy has been the preferred treatment for drug-refractory heart failure symptoms in obstructive hypertrophic cardiomyopathy (HCM). However, given the relatively youthful adult ages at which HCM surgery is usually performed, it is informative to evaluate longer-term results of myectomy after ≥10 years. We identified 139 consecutive obstructive HCM patients (50 ± 15 years of age; 55% men) who underwent surgical myectomy, 2003 to 2010 at Tufts HCM Center and followed 11.3 ± 2.7 years (range to 17). Operative mortality was low (0.6%) and left ventricular (LV) outflow gradients at rest were reduced from 56 ± 40 mm Hg preoperatively to 1 ± 7 mm Hg postoperatively, durable over the study period, with no patient requiring reoperation for the residual gradient. Over follow-up, 129 of 139 patients (93%) were alive ≥10 years after myectomy, including 17 patients ≥15 years. Of 118 patients with complete long-term clinical follow-up data, 109 (92%) experienced clinical improvement to New York Heart Association classes I or II. In 9 patients (8%) refractory class III/IV symptoms reoccurred 6.6 ± 3.9 years postoperatively, including 4 who ultimately underwent a heart transplant. After myectomy, there were 2 late HCM-related deaths, but none suddenly; notably 6 patients (12%) with prophylactic implantable cardioverter-defibrillators experienced appropriate therapy terminating ventricular tachycardia/ventricular fibrillation after myectomy. Survival following myectomy was 91% at 10 years (95% confidence interval: 85, 96%) not different from the age- and gender-matched general United States population (log-rank p = 0.64). In conclusion, myectomy provides permanent abolition of outflow gradients with reversal of heart failure and highly favorable long-term survival, representing a low-risk:high-benefit option when performed in experienced HCM centers. Myectomy did not protect absolutely against arrhythmic sudden death events, underscoring the importance of risk stratification in operative patients.

Randomized Trial of Metoprolol in Patients With Obstructive Hypertrophic Cardiomyopathy

BACKGROUND

The use of β-adrenergic receptor blocking agents in symptomatic patients with obstructive hypertrophic cardiomyopathy (HCM) rests on clinical experience and observational cohort studies.

OBJECTIVES

This study aimed to investigate the effects of metoprolol on left ventricular outflow tract (LVOT) obstruction, symptoms, and exercise capacity in patients with obstructive HCM.

METHODS

This double-blind, placebo-controlled, randomized crossover trial enrolled 29 patients with obstructive HCM and New York Heart Association (NYHA) functional class II or higher symptoms from May 2018 to September 2020. Patients received metoprolol or placebo for 2 consecutive 2-week periods in random order. The effect parameters were LVOT gradients, NYHA functional class, Canadian Cardiovascular Society (CCS) angina class, Kansas City Cardiomyopathy Questionnaire Overall Summary Score (KCCQ-OSS), and cardiopulmonary exercise testing.

RESULTS

Compared with placebo, the LVOT gradient during metoprolol was lower at rest (25 mm Hg [interquartile range (IQR): 15-58 mm Hg] vs 72 mm Hg [IQR: 28-87 mm Hg]; P = 0.007), at peak exercise (28 mm Hg [IQR: 18-40 mm Hg] vs 62 mm Hg [IQR: 31-113 mm Hg]; P < 0.001), and postexercise (45 mm Hg [IQR: 24-100 mm Hg] vs 115 mm Hg [IQR: 55-171 mm Hg]; P < 0.0001). During metoprolol treatment, 14% of patients were in NYHA functional class III or higher compared with 38% of patients receiving placebo (P < 0.01). Similarly, no patients were in CCS class III or higher during metoprolol treatment compared with 10% during placebo treatment (P < 0.01). These findings were confirmed by higher KCCQ-OSS during metoprolol treatment (76.2 ± 16.2 vs 73.8 ± 19.5; P = 0.039). Measures of exercise capacity, peak oxygen consumption, and N-terminal pro-B-type natriuretic peptide did not differ between the study arms.

CONCLUSIONS

Compared with placebo, metoprolol reduced LVOT obstruction at rest and during exercise, provided symptom relief, and improved quality of life in patients with obstructive HCM. Maximum exercise capacity remained unchanged. (The Effect of Metoprolol in Patients with Hypertrophic Obstructive Cardiomyopathy [TEMPO]; NCT03532802).

Hypertrophic cardiomyopathy in children

Hypertrophic cardiomyopathy (HCM) characterized by asymmetric ventricular septal hypertrophy, is the commonest cause of sudden cardiac death (SCD) in the young. The underlying etiology of HCM in the childhood and adolescent patients is diverse. Moreover, the prognosis of pediatric HCM depends on the age of presentation and etiology. Despite the complexity of children with obstructive HCM, surgical treatment results in a favorable outcome for carefully selected patients in experienced tertiary referral center in contemporary era. Implantable cardioverter-defibrillator (ICD) remains the most effective and reliable treatment to prevent SCD. New pediatric SCD risk prediction model, which has good discrimination and calibration and can distinguish patients who are most benefit from an ICD implantation, is expected to be further refined in the future.

Outcomes in Patients With Obstructive Hypertrophic Cardiomyopathy and Concomitant Aortic Stenosis Undergoing Surgical Myectomy and Aortic Valve Replacement

Background Hypertrophic cardiomyopathy (HCM) and aortic stenosis can cause obstruction to the flow of blood out of the left ventricular outflow tract into the aorta, with obstructive HCM resulting in dynamic left ventricular outflow tract obstruction and moderate or severe aortic stenosis causing fixed obstruction caused by calcific degeneration. We sought to report the characteristics and longer-term outcomes of patients with severe obstructive HCM who also had concomitant moderate or severe aortic stenosis requiring surgical myectomy and aortic valve replacement. Methods and Results We studied 191 consecutive patients (age 67±6 years, 52% men) who underwent myectomy and aortic valve (AV) replacement (90% bioprosthesis) at our center between June 2002 and June 2018. Clinical and echo data including left ventricular outflow tract gradient and indexed AV area were recorded. The primary outcome was death. Prevalence of hypertension (63%) and hyperlipidemia (75%) were high, with a Society of Thoracic Surgeons score of 5±4, and 70% of participants had no HCM-related sudden death risk factors. Basal septal thickness and indexed AV area were 1.9±0.4 cm and 0.72±0.2 cm²/m², respectively, while 100% of patients had dynamic left ventricular outflow tract gradient >50 mm Hg. At 6.5±4 years, 52 (27%) patients died (1.5% in-hospital deaths). One-, 2-, and 5-year survival in the current study sample was 94%, 91%, and 83%, respectively, similar to an age-sex-matched general US population. On multivariate Cox survival analysis, age (hazard ratio [HR], 1.65; 95% CI, 1.24-2.18), chronic kidney disease (HR, 1.58; 95% CI, 1.21-2.32), and right ventricular systolic pressure on preoperative echocardiography (HR, 1.28; 95% CI, 1.05-1.57) were associated with longer-term mortality, but traditional HCM risk factors did not. Conclusions In symptomatic patients with severely obstructive HCM and moderate or severe aortic stenosis undergoing a combined surgical myectomy and AV replacement at our center, the observed postoperative mortality was significantly lower than the expected mortality, and the longer-term survival was similar to a normal age-sex-matched US population.

Early and midterm results of extended septal myectomy: Indian experience

BACKGROUND AND OBJECTIVES

Hypertrophic obstructive cardiomyopathy (HOCM) is a genetic disorder, which is a cause of significant morbidity and sudden cardiac death. Extended septal myectomy (ESM) is the therapeutic gold standard to treat left ventricular outflow tract obstruction (LVOTO) in HOCM resulting in long-term symptomatic relief. The aim of the study was to assess the impact of ESM on midterm symptom relief, LVOTO, and survival in patients suffering from HOCM in the Indian population.

METHODS

We retrospectively analyzed clinical data of 36 consecutive symptomatic patients with HOCM having symptoms refractory to medical treatment and LVOTO with resting gradient ≥ 50 mmHg and who underwent ESM at our institution from 2010 to 2019. Preoperative and postoperative transthoracic echocardiography was performed to assess left ventricular outflow tract (LVOT) gradient, septal thickness, and assessment of valvar and cardiac function.

RESULTS

ESM was performed successfully in all 36 patients. The mean preoperative LVOT gradient was 113.06 ± 36.70 mmHg and decreased to 15.17 ± 7.30 mmHg (p < .0001) in the initial postoperative period. There were two in-hospital deaths (5.6%). There was no further mortality in the subsequent follow-up. The mean septal thickness was 23.89 ± 5.77 mm preoperatively and 13.17 ± 3.48 mm (p < .0001) postoperatively. During a mean follow-up of 2 years, the NYHA functional class improved from 3.50 ± 0.70 (III-IV) to 1.50 ± 0.70 (I) (p < .0001).

CONCLUSIONS

ESM results in immediate abolition of mechanical obstruction to LVOT with normalization of left ventricular pressure and eliminates symptoms associated with HOCM.

Impact of septal myectomy on diastolic function in patients with obstructive hypertrophic cardiomyopathy

Background

The impact of septal myectomy on diastolic function in patients with obstructive hypertrophic cardiomyopathy is not well studied.

Methods

A transcatheter hemodynamic study was performed before and 3 to 6 months after septal myectomy in 12 patients with obstructive hypertrophic cardiomyopathy (HCM).

Results

Postoperative hemodynamic studies were done 4.4±1.2 months after myectomy. The left ventricular outflow tract peak-to-peak gradient decreased from 83.2±43.3 mmHg preoperatively to 11.6±4.3 mmHg after myectomy (P<0.00). The left ventricular diastolic time constant (Tau) was 64.2±26.1 ms before surgery and 42.2±15.7 ms postoperatively (P=0.029). The average left atrial pressure (LAP) decreased from 20.2±7.0 to 12.1±4.5 mmHg after myectomy (P=0.008). Pulmonary artery hypertension was present in 6 patients preoperatively and remained in 2 patients after myectomy. Mean pulmonary artery pressure decreased from 29.3±16.2 to 20±6.7 mmHg after surgery (P=0.05), and the systolic pulmonary artery pressure decreased from 46±26.9 to 30.5±8.3 mmHg (P=0.048). Pulmonary vascular resistance decreased from 5.7±4.1 to 3.6±1.6 wood after surgery (P=0.032).

Conclusions

Septal myectomy improved left ventricular diastolic function and subsequently relieved the right ventricular congestion in patients with obstructive HCM.

Study design and rationale of VALOR-HCM: evaluation of mavacamten in adults with symptomatic obstructive hypertrophic cardiomyopathy who are eligible for septal reduction therapy

BACKGROUND

Hypertrophic cardiomyopathy (HCM) is a primary myocardial disorder which frequently leads to symptoms such as dyspnea and exercise intolerance, often due to severe dynamic left ventricular outflow tract obstruction (LVOTO). Current guideline-recommended pharmacotherapies have variable therapeutic responses to relieve LVOTO. In recent phases 2 and 3, clinical trials for symptomatic obstructive HCM (oHCM), mavacamten, a small molecule inhibitor of β-cardiac myosin has been shown to improve symptoms, exercise capacity, health status, reduce LVOTO, along with having a beneficial impact on cardiac structure and function.

METHODS

VALOR-HCM is designed as a multicenter (approximately 20 centers in United States) phase 3, double-blind, placebo-controlled, randomized study. The study population consists of approximately 100 patients (≥18 years old) with symptomatic oHCM who meet 2011 American College of Cardiology/American Heart Association and/or 2014 European Society of Cardiology HCM-guideline criteria and are eligible and willing to undergo septal reduction therapy (SRT). The study duration will be up to 138 weeks, including an initial 2-week screening period, followed by16 weeks of placebo-controlled treatment, 16 weeks of active blinded treatment, 96 weeks of long-term extension, and an 8-week posttreatment follow-up visit. The primary endpoint will be a composite of the decision to proceed with SRT prior to or at Week 16 or remain guideline eligible for SRT at Week 16. Secondary efficacy endpoints will include change (from baseline to Week 16 in the mavacamten group vs placebo) in postexercise LVOT gradient, New York Heart Association class, Kansas City Cardiomyopathy Questionnaire clinical summary score, NT-proBNP, and cardiac troponin. Exploratory endpoints aim to characterize the effect of mavacamten on multiple aspects of oHCM pathophysiology.

CONCLUSIONS

In severely symptomatic drug-refractory oHCM patients meeting guideline criteria of eligibility for SRT, VALOR-HCM will primarily study if a 16-week course of mavacamten reduces or obviates the need for SRT using clinically driven endpoints.

Perioperative Implications of the 2020 American Heart Association/American College of Cardiology Guidelines for the Diagnosis and Treatment of Patients with Hypertrophic Cardiomyopathy: A Focused Review

Hypertrophic cardiomyopathy is a complex disease with significant implications for patients and the physicians called upon to care for them during the perioperative period. In this article, the 2020 American Heart Association and American College of Cardiology clinical practice guidelines for the evaluation and management of pediatric and adult patients with hypertrophic cardiomyopathy are reviewed, with a particular focus on perioperative considerations for the anesthesiologist.

Hypertrophic cardiomyopathy surgery: Perioperative anesthetic management with two different and combined techniques

Hypertrophic cardiomyopathy (HOCM) is the most common genetic heart disorder and the most common cause of sudden cardiac death among young population and a major cause of disability for patients of any age. An extended transaortic septal myectomy is the definitive treatment. It is very important to have a good knowledge of the characteristic pathophysiology of the disease in order to optimize intraoperative treatment of these patients. We present a case of a 68-year old woman who underwent hypertrophic elective cardiomyopathy surgery. Anesthetic management is crucial to guarantee maximum safety, since HOCM has the capacity to produce hemodynamic events of such severity that put patient's life at risk. The use and combination of intraoperative transesophageal echocardiography (TEE) and direct measurement of the left ventricular outflow tract gradient provides vital information to ensure successful surgical outcome in patients with HOCM.

Mini-invasive surgical instruments in transaortic myectomy for hypertrophic obstructive cardiomyopathy: a single-center experience with 168 cases

BACKGROUND

Although septal myectomy is a standard strategy for managing patients with hypertrophic obstructive cardiomyopathy (HOCM) and drug-refractory symptoms, so far, only a few experienced myectomy centers exist globally. Mainly, this can be explained by the many technical challenges presented by myectomy. From our clinical experience, applying the mini-invasive surgical instruments during myectomy potentially reduces the technical difficulty. This study reports the preliminary experience regarding transaortic septal myectomy using mini-invasive surgical instruments for managing patients with HOCM and drug-refractory symptoms; also, we evaluate the early results following myectomy.

METHODS

Between March 2016 and March 2019, consecutive HOCM patients who underwent isolated transaortic septal myectomy using the mini-invasive surgical instruments were enrolled in this analysis. Intraoperative, in-hospital and follow-up results were analyzed.

RESULTS

We included 168 eligible patients (83 males, mean 56.8 ± 12.3 years). The midventricular obstruction was recorded in 7 (4.2%) patients. All patients underwent transaortic septal myectomy with a mean aortic cross-clamping time of 36.0 ± 8.1 min. During myectomy, 9 (5.4%) patients received repeat aortic cross-clamping. Surgical mortality was 0.6%. Notably, 5 (3.0%) patients developed complete atrioventricular block, they needed permanent pacemaker implantation. The median follow-up time was 6 months; however, no follow-up deaths occurred with a significant improvement in New York Heart Association functional status. We reported a sharp decrease in the maximum gradients from the preoperative value (11.6 ± 7.4 mmHg vs. 94.4 ± 22.6 mmHg, p < 0.001). The median degree of mitral regurgitation fell to 1.0 (vs. 3.0 preoperatively, p < 0.001) with a significant reduction in the proportion of moderate or more regurgitation (1.2% vs. 57.7%, p < 0.001).

CONCLUSIONS

Mini-invasive surgical instruments may be beneficial in reducing the technical challenges of transaortic septal myectomy procedure. Of note, transaortic septal myectomy using the mini-invasive surgical instruments may present with favorable results.

Hemodynamic determinants of left atrial strain in patients with hypertrophic cardiomyopathy: A combined echocardiography and CMR study

Background

Left atrial (LA) strain is associated with symptomatic status and atrial fibrillation in patients with hypertrophic cardiomyopathy (HCM). However, hemodynamic determinants of LA reservoir (LARS), conduit, and pump strains have not been examined and data are needed on the relation of LA strain with exercise tolerance in HCM.

Methods

Fifty HCM patients with echocardiographic and CMR imaging within 30 days were included. Left ventricular (LV) volumes, mass, EF, scar extent, extracellular volume fraction (ECV), and LA maximum volume were measured by CMR. Echo studies were analyzed for mitral inflow, pulmonary vein flow, mitral annulus tissue Doppler velocities, LV global longitudinal strain, and LA strain. Twenty six patients able and willing to exercise underwent cardiopulmonary stress testing for peak oxygen consumption (MVO2), and V_E/V_CO2 slope. Patients were followed for clinical events.

Findings

LARS was significantly associated with indices of LA systolic function, LV GLS, and LV filling pressures (P<0.05). Conduit strain was significantly associated with mitral annulus early diastolic velocity and ECV, whereas LA pump strain was determined by LA systolic function and indices of LV end diastolic pressure (all P<0.05). LARS and conduit strain were significantly higher in patients who achieved ≥80% of MVO₂. LARS, conduit, and pump strains were significantly associated with atrial fibrillation (P<0.05).

Conclusions

LV structure, systolic and diastolic function, and LA systolic function determine the 3 components of LA strain. LA strain is associated with exercise tolerance and clinical events in patients with HCM.