Perfusion Imaging With Myocardial Contrast Echocardiography in HCM

Study Overview
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Brief Summary
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The objective of this study is to determine whether myocardial contrast echocardiography in patients with cardiomyopathy (HCM) can detect resting hypo-perfusion due to fibrosis or stress induced perfusion defects due to associated abnormalities in intramyocardial arteries and the microcirculation. A secondary aim will be to determine whether abnormalities in perfusion are associated with either severity of symptoms (chest pain and dyspnea), presence of arrhythmias, and regional function of the septum.

Conditions
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Hypertrophic Cardiomyopathy

Intervention / Treatment
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* Drug: Echo and myocardial contrast echocardiography perfusion imaging


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age 18-80 years Established diagnosis of HCM Exclusion Criteria: Known history of coronary or peripheral artery disease History of myocardial infarction Pregnant or lactating females Hypersensitivity to any ultrasound contrast agent Evidence right-to-left or bi-directional intracardiac shunt Moderate or greater valve disease other than from HCM (systolic anterior motion of the mitral valve) History of septal ablation or myectomy Hemodynamic instability Pacemaker dependent heart rhythm

Ages Eligible for Study
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Minimum Age: 19 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: Diagnostic
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Patients with HCM<br>This is a prospective, non-blinded single center study. Subjects with known HCM with variant will be recruited. MCE at rest and during vasodilator stress will be performed. Full echocardiography including for diastolic function and regional strain imaging will also be performed. Patient history and questionnaires will be used for evaluation of symptoms and arrhythmias. | Drug: Echo and myocardial contrast echocardiography perfusion imaging<br>* Myocardial blood flow will be assessed by myocardial contrast echo. Perfusion at rest and stress will be quantified and compared to patient sx, degree of dysfunction on echo strain imaging, and degree of fibrosis on magnetic resonance imaging (when available) that was ordered as part of routine clinical care. Myocardial contrast echocardiography will be performed by intravenous administration of ultrasound contrast agent (Definity or Lumason) using FDA-approved dose limits. Vasodilator stress during MCE imaging will be performed using regadenoson at FDA-approved doses.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Myocardial perfusion (ml/min/g) in the hypertrophied segment on myocardial contrast echo | Myocardial contrast echo will be used to measure myocardial perfusion in ml/min/g of tissue in the hypertrophied segment. The data will be analyzed both in terms of absolute value of ml/min/g and also as a ration to normal tissue. | One hour | 
| Myocardial blood flow reserve in the hypertrophied segment on myocardial contrast echo | Myocardial blood flow reserve on myocardial contrast echo (ratio of flow during hyperemia to rest) will be calculated for the hypertrophied segment and expressed as an absolute value and relative to normal segments. | One hour | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Spatial distribution of blood flow on myocardial contrast echocardiography | Myocardial contrast echocardiography performed at baseline will be analyzed using mathematical algorithms that define how homogenous or heterogenous blood flow distribution is in the hypertrophied segment. These values will be described by wavelet energy levels (dimensionless). | One hour |