Nitrate Testing for Coronary Artery Spasm

(CRT-NITRO Trial)

Overseen By Bonnie Ostergren

Age: 18+

Sex: Any

Trial Phase: Academic

Sponsor: Baylor Research Institute

Must not be taking: Long-acting nitrates, PDE-5 inhibitors

Disqualifiers: Coronary artery disease, others

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

Compensation: Varies

Number of Visits: 1

Duration: Intra op

50 Participants Needed

Trial Summary

What is the purpose of this trial?

This single-arm, multi-center, prospective study will assess the coronary flow reserve (CFR), index of microcirculatory resistance (IMR), and determinants thereof (transit time, Pa, Pd) in patients before and after intracoronary nitroglycerine.

Will I have to stop taking my current medications?

You may need to stop taking long-acting nitrate therapies and PDE-5 inhibitors (like sildenafil or tadalafil) at least 48 hours before joining the trial.

What data supports the effectiveness of the drug Intracoronary Nitrate Testing for coronary artery spasm?

Research shows that nitrates, like isosorbide dinitrate, can quickly relieve coronary spasms and prevent them in most cases. Additionally, nitroglycerine has been shown to improve symptoms and prevent spasms in patients with different types of coronary artery spasms. ^{1 2 3 4 5}

Is intracoronary nitrate testing safe for humans?

Intracoronary nitrate testing, specifically using isosorbide dinitrate, is generally considered safe for diagnosing coronary artery spasm, as it quickly relieves spasms and prevents most cases of arterial spasm. Side effects like elevated blood pressure, headache, and chest symptoms are infrequent. ^{1 2 3 6 7}

How does the drug Intracoronary Nitrate Testing differ from other treatments for coronary artery spasm?

Intracoronary Nitrate Testing is unique because it involves directly administering nitrates into the coronary arteries to quickly relieve spasms, often within two minutes, and prevent further spasms. This method allows for a personalized assessment of nitrate responsiveness, which can help tailor treatment for different subtypes of coronary artery spasm. ^{2 3 8 9 10}

Eligibility Criteria

This trial is for adults being evaluated for angina without obvious coronary artery disease, who can follow the study plan and give written consent. It excludes those with prior heart interventions, recent nitrate or PDE-5 inhibitor use, significant health risks as judged by doctors, minors, prisoners, pregnant individuals, and anyone unable to consent.

Inclusion Criteria

Patient being evaluated for ANOCA or INOCA

Patient should be able to comply with the protocol

Provide written informed consent before study participation

Exclusion Criteria

Any other condition or co-morbidity which, in the opinion of the investigator or operator, may pose a significant hazard to the subject if he or she is enrolled in the study

I have heart disease affecting my arteries.

I have had procedures done on my heart's arteries.

Timeline

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Treatment

Participants undergo coronary reactivity testing with and without intracoronary nitrate administration

Intra op

1 visit (in-person)

Follow-up

Participants are monitored for safety and effectiveness after treatment

4 weeks

Treatment Details

Interventions

• Intracoronary Nitrate Testing

Trial Overview The study examines how blood flow in heart arteries responds before and after using a nitrate drug during a coronary reactivity test. This helps understand if nitrates affect measurements like CFR and IMR that assess heart blood flow issues.

Participant Groups

Group I: Coronary Reactivity Testing with and without intracoronary nitroglycerine Experimental Treatment 1 Intervention

CRT will be performed in the left anterior descending and right coronary arteries. The following measures will be obtained in each of the coronaries first without intracoronary nitrates followed by a dose of 200-500 mcg of intracoronary nitrates and repeat measurements: * Coronary flow reserve (CFR) (normal \> 2.0) * Index of microvascular resistance (IMR) (normal \<25) * Resting ratio of distal coronary pressure to aortic pressure (Pd/Pa) (normal \< 0.91) * Resting and hyperemic (using intravenous adenosine) transit time (Tm) * Resting full-cycle ratio (RFR) * Hyperemic (using intravenous adenosine) fractional flow reserve (FFR) * Resistive reserve ratio (RRR)

Who Is Running the Clinical Trial?

Baylor Research Institute

Lead Sponsor

Trials

210

Recruited

205,000+

References

1. Japan pubmed.ncbi.nlm.nih.gov

[Intracoronary administration of ergonovine maleate for detecting vasospastic angina; one dose method]. [2015]

2. France pubmed.ncbi.nlm.nih.gov

[Nitrate derivatives and coronary vasomotricity]. [2013]

3. United States pubmed.ncbi.nlm.nih.gov

Acetylcholine Re-Challenge After Intracoronary Nitroglycerine Administration. [2022]

4. United States pubmed.ncbi.nlm.nih.gov

Coronary arteriographic findings during early hours of acute myocardial infarction: response to intracoronary injection of nitrates. [2017]

5. United States pubmed.ncbi.nlm.nih.gov

Achieving sustained improvement in myocardial perfusion: role of isosorbide mononitrate. [2019]

6. Switzerland pubmed.ncbi.nlm.nih.gov

Acetylcholine Use in Modern Cardiac Catheterization Laboratories: A Systematic Review. [2022]

7. United States pubmed.ncbi.nlm.nih.gov

Provocation of coronary artery spasm. [2015]

8. United States pubmed.ncbi.nlm.nih.gov

Coronary artery spasm: recognition and treatment. [2015]

9. England pubmed.ncbi.nlm.nih.gov

Myocardial ischemia from coronary arterial spasm. [2019]

10. Japan pubmed.ncbi.nlm.nih.gov

Microvascular angina accompanied by epicardial coronary artery spasm. [2019]