CO2 as a Stress Agent for Perfusion Imaging
This trial is active, not recruiting.
|Condition||coronary artery disease|
|Treatments||delivery of precise levels of carbon dioxide with the respiract™ gen4 sequential gas delivery system, delivery of rubidium radioisotope (rb-82) using the automated pump/elution system|
|Sponsor||Ottawa Heart Institute Research Corporation|
|Start date||March 2014|
|End date||February 2017|
|Trial size||60 participants|
|Trial identifier||NCT02043535, 20140012|
Myocardial perfusion imaging (MPI) is a nuclear scan using a radioisotope to see blood flow to the muscles of the heart when the heart is at rest and when it is under stress. The stress test in MPI can be done using medications, such as adenosine, that dilate coronary arteries and increase blood flow. Similarly, elevated carbon dioxide (CO2) levels in the blood, or hypercapnia, also dilates arteries and increases blood flow. Thornhill Research Inc. has developed the RespirAct ™ Gen4 sequential gas delivery system used to control CO2 levels in the blood. The RespirAct ™ Gen4 can deliver precise amounts of CO2 through a mouthpiece for inhalation to increase CO2 levels in the blood and thereby increasing blood flow like during stress.
The objective of this study is to compare the differences in blood flow through the arteries of the heart during stress with hypercapnia and adenosine MPI. The imaging will be done using positron emission tomography (PET) with the radioisotope, or tracer, called Rubidium (Rb-82). The Rb-82 is given through a pump, or elution system.
The investigators hypothesize that hypercapnia will induce a stress-to-rest increase in myocardial blood flow by a factor of 2 or more in myocardial regions supplied by non-stenotic arteries in normal volunteers and participants with coronary artery disease.
|Endpoint classification||efficacy study|
|Intervention model||single group assignment|
Myocardial blood flow differences
time frame: Difference between baseline rest scan blood flow and hypercapnia stress scan myocardial blood flow at 50 mmHg, 55 mmHg, 60 mmHg levels from baseline. Imaging and intervention analysis will be complete in 4 years.
Absolute myocardial blood flow differences between end-tidal CO2 scans
time frame: Difference between baseline and 60 mmHg PetCO2. Imaging and intervention analysis will be complete in 4 years.
Difference bewteen absolute myocardial blood flow with hypercapnia and with adenosine stress.
time frame: Quantification and comparison of the differences in myocardial blood flow with adenosine stress and increasing levels of CO2 as a stress agent. Imaging and intervention analysis will be complete in 4 years.
Male or female participants at least 18 years old.
- Age ≥ 18 years old
- BMI ≤ 40 kg/m2
- Able and willing to comply with the study procedures
- Written informed consent
- Participants with documented coronary artery disease
- Stable coronary artery disease on a stable medication regime.
- Healthy volunteers without known heart disease
- Low risk of coronary artery disease (CAD)
- History or risk of severe bradycardia (heart rate < 50 beats per minute) not related to chronotropic drugs
- Known second- or third-degree Atrio-ventricular block without pacemaker
- Atrial flutter or atrial fibrillation
- Dyspnea (NYHA III/IV), wheezing asthma or Chronic Obstructive Pulmonary Disease (COPD)
- Coronary artery bypass graft (CABG) surgery within 60 days prior to screening or at any time after consent
- Percutaneous coronary intervention (PCI) within 30 days prior to screening or at any time following consent
- Acute myocardial infarction or acute coronary syndrome within 60 days prior to screening or at any time following consent
- Recent use of dipyridamole, dipyridamole-containing medications (e.g. Aggrenox)
- Known hypersensitivity to adenosine
- Breastfeeding or pregnancy
- Claustrophobia or inability to lie still in a supine position
- Unwillingness or inability to provide informed consent
|Official title||Effects of Controlled Hypercapnic Stimulation on Myocardial Blood Flow Measured With Positron Emission Tomography|
|Principal investigator||Terrence D Ruddy, MD|
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