CO2 as a Stress Agent for Perfusion Imaging (CO2 STRESS)

University of Ottawa Heart Institute

Status: Terminated

Conditions: Coronary Artery Disease

Treatments: Device: Delivery of precise levels of carbon dioxide with the RA-MR™ Virtual Sequential Gas Delivery System.; Device: Delivery of rubidium radioisotope (Rb-82) using the automated pump/elution system

Study type: Interventional

Funder types: Other

Identifiers

NCT02043535

20140012

Details and patient eligibility

About

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 persantine, 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 RA-MR™ sequential gas delivery system used to control CO2 levels in the blood. The RA-MR™ 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.

Enrollment: 20 patients

Sex: All

Ages: 18+ years old

Volunteers: Accepts Healthy Volunteers

Inclusion criteria

For all participants

• 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)

Exclusion criteria

• 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

Trial design

Primary purpose: Diagnostic

Allocation: N/A

Interventional model: Single Group Assignment

Masking: None (Open label)

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20 participants in 1 patient group

Myocardial blood flow quantification

Other group

Description:

The RA-MR™ Virtual Sequential Gas Delivery System. : delivery of CO2 in increasing levels. Rubidium Elution System: delivery of Rb-82 through an automated pump system for myocardial PET perfusion imaging. Persantine stress myocardial PET perfusion imaging: as a standard for comparison.

Treatment:

Device: Delivery of rubidium radioisotope (Rb-82) using the automated pump/elution system

Device: Delivery of precise levels of carbon dioxide with the RA-MR™ Virtual Sequential Gas Delivery System.