Transapical Beating-Heart Septal Myectomy in Patients With Symptomatic Nonobstructive Hypertrophic Cardiomyopathy

Study Overview
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Brief Summary
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The primary purpose of this study is to evaluate the feasibility, the safety and the efficacy of the transapical beating-heart septal myectomy for the treatment of nonobstructive hypertrophic cardiomyopathy. This is a prospective, single-arm, single-center study.

Detailed Description
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Medical therapy is first recommended for patients with nonobstructive hypertrophic cardiomyopathy administrated at onset of heart failure symptoms. As the disease progresses, patients with global ejection fraction < 50% should be evaluated with respect to eligibility and motivation for heart transplant. However, for those with preserved ejection fraction and drug-refractory heart failure symptoms, there is still no optimal therapy. Some patients with increased left atrial volume and/or diastolic dysfunction can be recognized as a result of excessive myocardial hypertrophy, and the septal resection for these patients may be beneficial. However, conventional septal myectomy is hindered by the demanding expertise that is needed to sufficient resection of hypertrophied septal myocardium while guarantee safety. To increase the visualization and minimize the surgical injury of conventional septal myectomy, we have invented a novel beating-heart myectomy device. Through a mini-thoractomy, septal myectomy could be accomplished via a transapical access in the beating heart using the beating-heart myectomy device. The whole process of resection is monitored, navigated, and evaluated by real-time transesophageal and transthoracic echocardiography. Left ventricular morphology and hemodynamics are evaluated each time after resection. Multiple resections are performed to tailor sufficient enlargement of left ventricular end-diastolic volume and improvement of mitral regurgitation, while preventing iatrogenic injuries. After transapical beating-heart septal myectomy, patients are scheduled to be seen for follow-up visits at discharge (about 7 days post operation) and 3 months.

Official Title
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Minimally Invasive Transapical Beating-Heart Septal Myectomy in Patients With Nonobstructive Hypertrophic Cardiomyopathy

Conditions
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Nonobstructive Hypertrophic Cardiomyopathy

Intervention / Treatment
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* Procedure: Transapical beating-heart septal myectomy


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients whose maximal ventricular septal wall thickness ≥ 15 mm. Patients with heart function of New York Heart Association ≥ class II. Patients with drug-refractory symptoms or intolerable to pharmaceutical therapies. Patients who was informed the nature of the clinical trial, consented to participate in all of the activities of the clinical trial, and signed the informed consent form Exclusion Criteria: Patients who were pregnant. Patients who had concomitant diseases such as intrinsic valvular disease or coronary artery disease that needed open-heart surgery. Patients who had severe heart failure with left ventricle ejection fraction < 40%. Patients whose estimated life expectancy < 12 m. Patient who were non-compliant. Patients under circumstances which were considered not suitable or prohibitive for participating the clinical trial at the discretion of the attending medical team and the researchers.

Ages Eligible for Study
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Minimum Age: 8 Years
Maximum Age: 80 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Intervention Model: Single Group Assignment
Interventional Model Description: Experimental Group: Beating-heart myectomy device
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Nonbstructive Hypertrophic Cardiomyopathy<br>Transapical beating-heart septal myectomy for the patient with nonobstructive hypertrophic cardiomyopathy and Heart Failure. | Procedure: Transapical beating-heart septal myectomy<br>* We have invented a beating-heart myectomy device.Through a minimally invasive intercostal incision, septal myectomy could be accomplished via a transapical access in the beating heart using the device. The whole process of resection is monitored, navigated, and evaluated by real-time transesophageal and transthoracic echocardiography. Left ventricular end-diastolic volume and the grade of mitral regurgitation are evaluated each time after resection. Multiple resections are performed to tailor the muscular resection for sufficient enlargement of left ventricular end-diastolic volume and improvement of mitral regurgitation, while preventing iatrogenic injuries.<br>* Other names: Minimally invasive transapical septal myectomy in the beating hearts;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| All-cause mortality | Death from any cause during the observation period. | 3 months | 
| Procedural success | A reduction of ≥1 New York Heart Association (NYHA) class and a decrease of ≥ 20% of left atrial volume | 3 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Device success | Successful accession, delivery, and retrieval of the resection device, successful resection of the septal myocardium, mitral regurgitation (MR) ≤ grade 2+ during operation after resection, and free from conversion to midline thoracotomy during operation. | 1 day | 
| Septal thickness | Basal and mid septal thickness as measured by echocardiography. | 7 days and 3 months | 
| Left ventricle mass | Left ventricle mass index (the ratio of left ventricle mass to body weight) as measured by cardiac magnetic resonance. | 7 days and 3 months | 
| Left atrial volume | The left atria volume as measured by echocardiography. | 7 days and 3 months | 
| Major adverse cardiovascular and cerebral events | In-hospital mortality, atrioventricular block that need permanent pacemaker implantation, sternotomy conversion, iatrogenic ventricular septal perforation, iatrogenic valvular injury, imaging examination-validated cerebral complications. | 3 months | 
| New York Heart Association class | New York Heart Association class, including grade I, grade II, grade III, grade IV. A higher grade means worse heart function. | 7 days and 3 months | 
| 6-minute walking test | 6-minute walking test. A longer distance means better heart function. | 3 months | 
| Heart function-associated quality of life | Score of the Kansas City Cardiomyopathy Questionnaire. A higher score means better heart function. | 7 days and 3 months | 
| Evaluation of the mitral valve | Grade of mitral regurgitation and systolic anterior motion as measured by echocardiography. | 7 days and 3 months | 
| Left ventricular outflow tract diameter | Left ventricular outflow tract diameter as measured by echocardiography. | 7 days and 3 months | 
| Left ventricular end-diastolic volume | Left ventricular end-diastolic volume as measured by cardiac magnetic resonance. | 3 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Nonobstructive Hypertrophic Cardiomyopathy, Septal Myectomy, Mitral Regurgitation, Transapical, Off-pump, Minimally invasive