Carbon Dioxide for Coronary Artery Disease

(NIMO-CAD Trial)

Overseen By Chandana Saha, PhD

Age: 18+

Sex: Any

Trial Phase: Academic

Sponsor: Indiana University

Disqualifiers: Myocardial infarction, Hypotension, Cardiac disease, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Compensation: Varies

Number of Visits: 1

Duration: 1 day

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial explores a new method to assess blood flow in individuals with coronary artery disease, a condition where the heart's blood vessels narrow or become blocked. The study uses a device called RespirAct to determine if carbon dioxide can safely and effectively measure blood flow through the heart. It seeks participants who may have coronary artery disease and have shown signs of limited blood flow to the heart in tests. However, individuals with past heart attacks, severe heart conditions, or asthma are not eligible. As an unphased trial, this study offers participants the chance to contribute to innovative research that could enhance future diagnostic methods for coronary artery disease.

Will I have to stop taking my current medications?

The trial information does not specify whether you need to stop taking your current medications. It's best to discuss this with the trial coordinators or your doctor.

What prior data suggests that utilizing carbon dioxide for assessing coronary blood flow is safe for subjects with coronary artery disease?

Research has shown that using carbon dioxide (CO2) for medical imaging is generally safe and well-tolerated. In past studies, CO2 replaced traditional contrast dyes in imaging tests. These studies found that CO2 can be a safe choice without causing kidney issues or allergic reactions.

For instance, one study used CO2 in angiography (a method to see blood vessels) and demonstrated good safety results. Only a few participants reported minor symptoms, and no serious side effects occurred. This suggests that using CO2, as in the current study with RespirAct, could be safe for assessing blood flow in the heart for individuals with coronary artery disease (a condition where the heart's blood vessels are narrowed).

Overall, existing evidence supports the safety of CO2 in medical imaging, making it a promising option for further research. ^{1 2 3 4 5}

Why are researchers excited about this trial?

Unlike the standard treatments for coronary artery disease, which typically involve medications like statins and beta-blockers or procedures like angioplasty, RespirAct uses a novel approach by utilizing computer-controlled gas challenges with carbon dioxide. This method aims to improve blood flow and oxygen delivery to the heart by carefully manipulating carbon dioxide levels, potentially offering a non-invasive alternative. Researchers are excited about RespirAct because it could provide a new way to manage coronary artery disease, particularly for patients who might not respond well to conventional therapies.

What evidence suggests that RespireAct is effective for coronary artery disease?

Research has shown that using carbon dioxide with a device called RespirAct, which participants in this trial will experience, might help detect coronary artery disease (CAD). One study found that this method accurately identified CAD compared to a traditional procedure called invasive coronary angiography. This new approach could help doctors make better decisions by assessing CAD risk and improving patient outcomes. Although it's still early, these initial findings suggest potential benefits for patients with CAD. ^{6 7 8 9 10}

Are You a Good Fit for This Trial?

This trial is for individuals with coronary artery disease. Specific eligibility criteria are not provided, but typically participants would need to meet certain health conditions and agree to the study's procedures.

Inclusion Criteria

I am older than 18 years.

I have stable heart disease or it's suspected.

The SPECT/PET study indicates at least a mild to moderate myocardial ischemia (>5-9%) or fractional-flow-reserve (FFR) of <0.75.

Exclusion Criteria

Hypotension (systolic blood pressure < 100 mmHg)

Inability to voluntarily increase their breathing rate if prompted to do so

I have had a heart attack in the past.

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Treatment

Participants undergo computer-controlled gas challenges to assess coronary blood flow using carbon dioxide

1 day

1 visit (in-person)

Follow-up

Participants are monitored for safety and effectiveness after treatment

4 weeks

What Are the Treatments Tested in This Trial?

Interventions

• RespirAct

Trial Overview The trial is testing RespirAct, a method using carbon dioxide to assess blood flow in the coronary arteries. It's a pilot study focusing on how safe and feasible this technique is for patients with heart issues.

How Is the Trial Designed?

Group I: Coronary Artery Disease (CAD) Subjects Experimental Treatment 1 Intervention

Subjects with a of coronary artery disease will undergo computer-controlled gas challenges.

Who Is Running the Clinical Trial?

Indiana University

Lead Sponsor

Trials

1,063

Recruited

1,182,000+

Citations

1. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC8996676/

validation against invasive coronary angiography - PMC As an important step towards clinical translation, we demonstrated a good diagnostic accuracy for CAD detection using high-resolution CCMRA, with high ...

2. nature.com nature.com/articles/s41746-025-01655-6

Effectiveness of digital healthcare to improve clinical ... Digital healthcare demonstrates superior post-discharge optimization of CAD outcomes, significantly attenuating mortality and morbidity.

3. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC11720542/

Development and validation of a novel coronary artery ... This novel model could be used to assess CAD risk in patients with chest pain, optimize clinical decision making, and improve patient outcomes, ...

4. sciencedirect.com sciencedirect.com/science/article/pii/S2772963X23005434

Digital Health Programs to Reduce Readmissions in ... There was no significant reduction for mortality outcomes (RR: 1.72; 95% CI: 0.64-4.64) or major adverse cardiovascular events (RR: 0.68; 95% CI: 0.40-1.15).

5. biorxiv.org biorxiv.org/content/10.1101/2025.08.22.671781v1.full.pdf

Preservation of cerebral vascular and metabolic health with ... Data collection was conducted at the Montreal Heart Institute. Inclusion criteria for CAD patients required a confirmed history of coronary ...

6. clinicaltrials.gov clinicaltrials.gov/study/NCT06253884

Utilizing Carbon Dioxide for Assessing Coronary Blood ... This is a prospective pilot study to evaluate the safety, tolerability and technical feasibility of utilizing carbon dioxide for assessing coronary blood flow ...

7. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC7061263/

Carbon dioxide-angiography for patients with peripheral ... Carbon dioxide angiography represents a safe and effective alternative to the use of iodinated contrast medium.

8. sciencedirect.com sciencedirect.com/science/article/pii/S0378603X17301535

Accuracy and safety of CO2 digital subtraction angiography ... CO 2 DSA is a non-nephrotoxic alternative to traditional ICM DSA that could be safely used and well tolerated during endovascular management of lower extremity ...

9. medicine.iu.edu medicine.iu.edu/research-centers/cardiovascular/clinical-trials/ischemic-heart-disease

Ischemic Heart Disease Clinical Trials Objective: The purpose of this study is to evaluate the safety, tolerability and technical feasibility of utilizing carbon dioxide for assessing coronary blood ...

10. researchgate.net researchgate.net/publication/270964382_Automated_Carbon_Dioxide_Digital_Angiography_for_Lower-Limb_Arterial_Disease_Evaluation_Safety_Assessment_and_Comparison_With_Standard_Iodinated_Contrast_Media_Angiography

(PDF) Automated Carbon Dioxide Digital Angiography for ... Tolerable minor symptoms occurred in 3 patients. No allergic reactions or significant decline in renal function were observed in patients ...