Hyp Obst Cardiomyopathy

Hypertrophic ObsructiveCardiomyopathy:Should the Mitral Valve be Addressed During Septal Myectomy?

Hypertrophic Obstructive cardiomyopathy (HOCM) is the most common genetic cardiomyopathy, heterogeneous in phenotype and clinical course. The genotype-phenotype relationship and associated molecular mechanisms are still incompletely understood. In the HOCM milieu, increased energy cost of force production, impairing performance and mitochondrial function, may be associated to patients' genotype and/or phenotype

Study Overview

• Status: Unknown
• Conditions: Hypertrophic Obstructive Cardiomyopathy
• Intervention / Treatment: Other: The Septal myectom

Detailed Description

Hypertrophic Obstructive cardiomyopathy (HOCM) is the most common genetic cardiomyopathy, heterogeneous in phenotype and clinical course. The genotype-phenotype relationship and associated molecular mechanisms are still incompletely understood. In the HOCM milieu, increased energy cost of force production, impairing performance and mitochondrial function, may be associated to patients' genotype and/or phenotype (1).

Hypertrophic cardiomyopathy as a clinical entity was first described by Brock in 1957 (2). Hypertrophic cardiomyopathy is the most common cause of sudden cardiac death in young people, including competitive athletes (3).

The characteristic pathologic features of hypertrophic cardiomyopathy are asymmetric hypertrophy, especially of the interventricular septum myocardial fiber hypertrophy and disorganisation of myocardial cells, abnormal thickened intramyocardial coronary vessels ("small vessel disease") and interstitial fibrosis (4). In the majority of patients (approximately 90%), hypertrophy mainly involves the interventricular septum and anterolateral wall. In a minority of patients myocardial hypertrophy is confined to the apical part of the left ventricle (4).

Myocardial hypertrophy is not the only hallmark of hypertrophic Obsructive cardiomyopathy. Klues et al. have described anatomic alterations in the mitral apparatus which may be present in this disorder: an increase of the mitral valve area, increase in length of the anterior leaflet, abnormal laxity and anterior displacement of the valve (5). Mitral valve (MV) leaflets have an important role in the pathophysiological process of left ventricular (LV) outflow tract obstruction in patients with hypertrophic obstructive cardiomyopathy (HOCM). Systolic anterior motion (SAM) of the mitral apparatus and contact of the leaflets with the hypertrophied septum narrow the LV outflow, leading to dynamic pressure gradients and in many patients, mitral regurgitation (MR) (6).

Currently, surgery is the gold standard treatment for most drug refractory and severely symptomatic patients [New York Heart Association (NYHA) class III or IV] with obstructive HOCM [7].

The Septal myectomy is the preferred treatment of most patients with HOCM, and many studies have documented relief of symptoms and satisfactory late patient survival after relief of outflow tract gradients.

valve repair or replacement may be necessary (7). However, adequate septal myectomy relieves outflow tract gradients, SAM of the MV, and MR in many patients (6). Nevertheless, several reports have described adjunctive techniques of mitral valvuloplasty aimed at eliminating SAM of the MV (8,9).

Guidelines support decisions to select surgery for patients with mitral structural abnormalities. The 2011 American guidelines state: "Additionally, specific abnormalities of the mitral valve and its support apparatus can contribute significantly to the generation of outflow tract obstruction, suggesting the potential value of additional surgical approaches (e.g., plication, valvuloplasty, and papillary muscle relocation) and making myectomy more appropriate than alcohol septal ablation in some patients" (10)

Finally, An appreciation of mitral abnormalities in HCM has accumulated over the past 20 years (11). There has been a natural response by surgeons to this greater understanding of the contribution of mitral pathology to SAM. At myectomy, they have tried to avoid leaving unrepaired pathology by repairing the mitral valve (12).

• Study Type: Interventional
• Enrollment (Anticipated): 98
• Phase: Not Applicable

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 60 years (Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

1. All patients that present with hypertrophic obstructive cardiomyopathy (HOCM) with mean pressure gradient>50 mm Hg at rest or on provocation
2. HOCM patients with severe mitral regurgitation.
3. HOCM patients with New York Heart Association (NYHA) functional class II to IV despite optimal medical treatment consisting of -blocking agents, calcium channel blockers, or both.

Exclusion Criteria:

b. Exclusion criteria:

1. Non-obstructive physiological characteristics.
2. Previous MV surgery.
3. Patient with intrinsic pathology of the mitral valve.
4. Patients <18 years.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: septal myectomy alone versus septal myectomy; The aims of the present study is to: Compare the results of adequate septal myectomy alone versus septal myectomy + mitral repair in patients with HOCM.; Effect of mitral repair on outcome of patients with systolic anterior motion that accompanies HOCM.	Other: The Septal myectom; The Septal myectomy is the preferred treatment of most patients with HOCM, and many studies have documented relief of symptoms and satisfactory late patient survival after relief of outflow tract gradients. valve repair or replacement may be necessary

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
LVOT obstruction degree in cm by Echocardiography	The degree of the LVOT obstruction as measured in cm by echocardiography .	3 months
Systolic anterior motion of mitral valve	The presence of systolic anterior motion of mitral valve as assessed by post-operative echocardiography.	3 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Post-Operative complictions	Post-operative assessment by echocardiography for complications such as mitral regurgitation.	3 months
post-operative general condition	Assessment of post-operative general condition in terms of NYHA Classification.	3 Months
Post-operative mortality	assessment of post-operative mortality rate	3 months

Collaborators and Investigators

• Sponsor: Assiut University

Study record dates

Study Major Dates

• Study Start (Anticipated): May 1, 2020
• Primary Completion (Anticipated): May 1, 2022
• Study Completion (Anticipated): June 1, 2022

Study Registration Dates

• First Submitted: March 5, 2020
• First Submitted That Met QC Criteria: March 30, 2020
• First Posted (Actual): April 1, 2020

Study Record Updates

• Last Update Posted (Actual): April 1, 2020
• Last Update Submitted That Met QC Criteria: March 30, 2020
• Last Verified: March 1, 2020

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Heart Diseases; Cardiovascular Diseases; Pathological Conditions, Anatomical; Aortic Valve Disease; Heart Valve Diseases; Aortic Stenosis, Subvalvular; Aortic Valve Stenosis; Hypertrophy; Cardiomyopathies; Cardiomyopathy, Hypertrophic
• Other Study ID Numbers: HHosp

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No