Real Time Myocardial Perfusion Echocardiography for Coronary Allograft Vasculopathy

Study Overview
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Brief Summary
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Is real-time myocardial perfusion echocardiography (RTMPE) a feasible and effective non-invasive method to detect significant Coronary Allograft Vasculopathy in pediatric and adult cardiac transplant recipients? Will perfusion deficits correlate with significant coronary artery stenosis identified by standard stress echocardiography and Invasive Coronary Angiography (ICA), and identify diffuse small vessel disease more effectively than current non-invasive techniques?

Detailed Description
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Heart transplant recipients are susceptible to developing a unique disease that causes blockages in the arteries of the transplanted heart (coronary arteries) called Coronary Allograft Vasculopathy (CAV). Because CAV often progresses without symptoms, transplant recipients undergo regular surveillance testing so that CAV can be detected and treatment can be offered before significant damage to the transplanted heart occurs. Current tests used to detect CAV are either invasive (with risk of complications) or may not be able to detect CAV in its early stages. Myocardial contrast perfusion echocardiography is a safe non-invasive diagnostic test that may be well suited for detecting CAV, however has not been well studied in heart transplant recipients. This study examines the ability of myocardial contrast perfusion echocardiography to detect CAV in adult and pediatric heart transplant recipients, and compare those results to current standard testing strategies such as Invasive Coronary Angiography (ICA) and standard stress echocardiography. This will help determine whether myocardial contrast perfusion echocardiography is a better test for regular surveillance of CAV in adult and pediatric transplant recipients.

Official Title
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(RTMPE for CAV) Real Time Myocardial Perfusion Echocardiography for Detection of Coronary Allograft Vasculopathy in Cardiac Transplant Patients

Conditions
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Cardiac Allograft Vasculopathy

Intervention / Treatment
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* Drug: Perflutren Lipid Microsphere
* Procedure: RTMPE


Participation Criteria
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Eligibility Criteria
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Inclusion: Cardiac transplant recipients (> or equal to 10 months post transplant) Clinically followed at Mayo Clinic, Rochester Minnesota Exclusion: Standard contraindications to the use of ultrasound contrast and pharmacologic stress Recent (< 3 months) hospitalization for heart failure, acute coronary syndrome or allograft rejection Multi-organ transplant Known or suspected right-to-left, bi-directional, or transient right-to-left cardiac shunts Hypersensitivity to perflutren

Ages Eligible for Study
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Minimum Age: 1 Year

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: RTMPE<br>RTMPE with Perflutren Lipid Microsphere (DEFINITY) is a safe and feasible non-invasive technique commonly used to diagnose coronary disease, and offers an attractive alternative for CAV detection. | Drug: Perflutren Lipid Microsphere<br>* Definity (injectible suspension ultrasound contrast agent) will be diluted with saline for both Pediatric and Adult subjects. For pediatric subjects under 60kg (kilogram), the dose will be 20 MicroL/kg (MicroLiter/kilogram) diluted to the same concentration used in the adult dosing. Hand Injections will be performed at baseline, Pre-peak, and peak perfusion stages.<br>* Other names: Definity;Procedure: RTMPE<br>* Utilizes intravenous administration of biologically-inert microbubbles to assess myocardial perfusion and has demonstrated utility for identifying small vessel coronary artery disease.<br>* Other names: Real Time Myocardial Perfusion Echocardiography;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Number of Subjects With a Perfusion Defect | A perfusion defect will first be identified using clinically indicated invasive coronary angiography (ICA). The presence of a perfusion defect will then be identified using non-invasive real time myocardial perfusion echocardiography (RTMPE). | baseline |