Analysis of Coronary Reactivity Testing With and Without Intracoronary Nitrate Testing (CRT-NITRO)

April 30, 2026 updated by: Baylor Research Institute
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.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

This will be a single arm, multi-center, prospective interventional study. We will approach, consent, and enroll patients referred to the cardiac catheterization laboratory for coronary angiography for the indication of angina without obstructive coronary artery disease (CAD; lesions <50%, fractional flow reserve (FFR) >0.80, or non-hyperemic pressure index (RFR) <0.89). Patients will undergo invasive assessment with CRT first without IC nitrates followed by a dose of 200-500 mcg of intracoronary nitrates and repeat CRT.

Approximately 50 patients undergoing coronary angiography for evaluation of ANOCA or INOCA will be consented for this study.

The primary outcome will be comparing the variables assessed by CRT with the primary outcome being CFR before and after nitroglycerin administration.

The secondary outcomes will be IMR, Pd, Pa, RRR, and transit times before and after nitrates.

These variables will be compared to one another using paired t-tests and generalized estimating equations.

Study Type

Interventional

Enrollment (Estimated)

50

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  1. Aged 18 or older
  2. Patient being evaluated for ANOCA or INOCA
  3. Clinical suspicion for angina
  4. Patient should be able to comply with the protocol.
  5. Provide written informed consent before study participation.

Exclusion Criteria:

  1. Existing coronary artery disease
  2. Previous percutaneous interventions within the coronaries
  3. Current use (within 48 hours) of long-acting nitrate therapies
  4. Current use (within 48 hours) of PDE-5 inhibitors (sildenafil, tadalafil)
  5. 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.
  6. Children below 18 years, prisoners, pregnant people and patients who are unable to provide consent are excluded.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Other
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Coronary Reactivity Testing with and without intracoronary nitroglycerine

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)
Diagnostic test: Coronary reactivity testing with and without nitrates
CRT will be performed in the left and right coronary arteries. Measurements 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.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Assessment of CFR by CRT before and after nitrates
Time Frame: Intra op
The primary outcome will be comparing the variables assessed by CRT with the primary outcome being CFR before and after nitroglycerin administration.
Intra op

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
IMR, HMR, Pd/Pa, RRR, RFR, and transit times before and after nitrates.
Time Frame: Intra op
The secondary outcomes will be IMR, Pd, Pa, RRR, and transit times before and after nitrates.
Intra op

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Baylor Research Institute

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

May 21, 2025

Primary Completion (Estimated)

May 1, 2027

Study Completion (Estimated)

June 1, 2027

Study Registration Dates

First Submitted

March 20, 2025

First Submitted That Met QC Criteria

March 20, 2025

First Posted (Actual)

March 26, 2025

Study Record Updates

Last Update Posted (Actual)

May 5, 2026

Last Update Submitted That Met QC Criteria

April 30, 2026

Last Verified

March 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 025-193

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

Yes

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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