Non-invasive Evaluation of Patients With Angina and Non-obstructive Coronary Artery Disease (NEO-NOCAD)

This is a single-center, prospective interventional study evaluating noninvasive coronary function testing using transthoracic Doppler echocardiography of the left anterior descending coronary artery in patients with stable angina and nonobstructive coronary artery disease (ANOCA) who previously underwent invasive coronary function testing (adenosine and/or acetylcholine).

A group of age- and sex-matched healthy volunteers will be enrolled to support interpretation of potentially abnormal noninvasive responses observed in patients.

Study Overview

• Status: Not yet recruiting
• Conditions: ANOCA - Angina With Non-obstructive Coronary Arteries
• Intervention / Treatment: Diagnostic test: Coronary flow reserve assessed by Echocardiography

Detailed Description

Patients referred to the catheterization laboratory of Fondazione Policlinico Universitario A. Gemelli IRCCS for stable angina who show non-obstructive coronary artery disease at invasive coronary angiography and underwent invasive coronary function testing will be enrolled.

During a transthoracic echocardiographic Doppler examination of the left anterior descending coronary artery, participants will undergo three standardized stimuli (hyperventilation, cold pressor test, and dipyridamole) separated by 30-minute intervals, with peak diastolic velocity measured at baseline and at the end of each test.

For each stimulus, the coronary blood flow velocity response will be expressed as the ratio between peak and basal peak diastolic velocity.

Participants will also complete the Seattle Angina Questionnaire to assess symptom burden.

The primary aim of the study is to investigate the usefulness of studying coronary flow reserve by transthoracic color Doppler echocardiogram in reaching the diagnosis of microcirculation dysfunction and/or coronary vasomotor disturbance.

The secondary aim of the study was to assess whether abnormalities on the stress echocardiogram with dipyridamole, hyperventilation, and cold-pressor test are related to the patient's symptoms.

• Study Type: Interventional
• Enrollment (Estimated): 35
• Phase: Not Applicable

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

1. Age between 18 and 90 years;
2. ICA performed within the previous 12 months from enrollment and characterized by: (a) absence of obstructive CAD (<50% diameter reduction or FFR by >0.80); (b) invasive assessment of epicardial/microvascular spasm by acetylcholine test;
3. Signed informed consent.

Exclusion Criteria:

1. Presentation as an acute coronary syndrome (i.e. unstable chest pain) or a typical history of variant angina (frequent angina pain at rest with ST-segment elevation at the ECG, caused by recurrent coronary spasm);
2. Previous coronary revascularization with surgical intervention;
3. Asthma or known intolerance or contraindications to dipyridamole;
4. Serious medical conditions, including renal failure (eGFR <30 mL/min), liver diseases, malignancies, and acute or chronic inflammatory diseases;
5. Pregnancy;
6. Psychological conditions that might hamper patient co-operation;
7. Any condition that, in the judgment of the investigators, would make difficult for the patient to complete the study protocol;
8. Missed informed consent.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Diagnostic
• Allocation: Non-Randomized
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Non-invasive coronary flow reserve in patients with ANOCA; We will enroll patients referred to the catheterization laboratory of the Fondazione Policlinico Universitario A. Gemelli IRCCS for stable angina who showed non-obstructive coronary arteries at coronary angiography and underwent invasive coronary functional tests (adenosine and/or acetylcholine test).	Diagnostic test: Coronary flow reserve assessed by Echocardiography; All patients and controls will undergo the following tests during transthoracic echocardiographic Doppler examination of the left anterior descending coronary artery, with time intervals of 30 minutes from each other: hyperventilation test: the patient is asked to breathe at a rate of 30 respirations per minute, for 5 minutes;; cold pressor test: the patient puts his/her right hand in ice water for 2 minutes;; dipyridamole test: intravenous dipyridamole is administered at a dose of 0.84 mg/kg over 6 minutes; Peak diastolic velocity (PDV) of blood flow in the left anterior descending coronary artery will be measured before and at the end of each test by pulsed-wave Doppler, using a GE E95 echocardiographic machine. The ratio between peak flow velocity of coronary blood flow at peak of each test and the relative basal peak flow velocity of coronary blood flow is taken as the response of coronary blood flow velocity to each test.
Active Comparator: Non-invasive coronary flow reserve in healthy volunteers; To confirm the reliability of possible abnormal results of non-invasive coronary functional tests in angina and non-obstructive coronary arteries (ANOCA) patients, we will enroll healthy control subjects of similar age and gender of enrolled patients, selected among those referred to our ambulatory of clinical visits for a routine cardiological evaluation and undergo a screening stress test for coronary artery disease. They will undergo a dipyridamole stress echocardiogram, which is commonly used in clinical practice to investigate the presence of coronary artery disease.	Diagnostic test: Coronary flow reserve assessed by Echocardiography; All patients and controls will undergo the following tests during transthoracic echocardiographic Doppler examination of the left anterior descending coronary artery, with time intervals of 30 minutes from each other: hyperventilation test: the patient is asked to breathe at a rate of 30 respirations per minute, for 5 minutes;; cold pressor test: the patient puts his/her right hand in ice water for 2 minutes;; dipyridamole test: intravenous dipyridamole is administered at a dose of 0.84 mg/kg over 6 minutes; Peak diastolic velocity (PDV) of blood flow in the left anterior descending coronary artery will be measured before and at the end of each test by pulsed-wave Doppler, using a GE E95 echocardiographic machine. The ratio between peak flow velocity of coronary blood flow at peak of each test and the relative basal peak flow velocity of coronary blood flow is taken as the response of coronary blood flow velocity to each test.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Correlation (Phi coefficient) between TTE-induced vasoconstriction and acetylcholine-induced spasm at invasive assessment.	The primary aim of the study is to investigate the usefulness of studying coronary flow reserve by transthoracic color Doppler echocardiogram in reaching the diagnosis of coronary vasomotor disturbance.	Periprocedural

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Agreement between dipyridamole-induced non-invasive coronary flow reserve and invasive coronary flow reserve	Agreement between coronary flow reserve (CFR) measured by transthoracic echocardiography during dipyridamole stress and CFR measured during invasive coronary function testing. Unit of Measure: Pearson correlation coefficient	Periprocedural
Agreement between cold pressor test-induced non-invasive coronary flow reserve and invasive coronary flow reserve	Agreement between coronary flow reserve (CFR) measured by transthoracic echocardiography during cold pressor test and CFR measured during invasive coronary function testing. Unit of Measure: Pearson correlation coefficient	Periprocedural
Association between abnormal non-invasive coronary vasomotor response and angina symptoms	Comparison of Seattle Angina Questionnaire (SAQ) summary score between patients with abnormal versus normal coronary vasodilator response during stress echocardiography. Unit of Measure: SAQ summary score (0-100)	Periprocedural

Collaborators and Investigators

• Sponsor: Fondazione Policlinico Universitario Agostino Gemelli IRCCS

Study record dates

Study Major Dates

• Study Start (Estimated): March 1, 2026
• Primary Completion (Estimated): October 1, 2026
• Study Completion (Estimated): November 1, 2026

Study Registration Dates

• First Submitted: January 21, 2026
• First Submitted That Met QC Criteria: February 13, 2026
• First Posted (Actual): February 20, 2026

Study Record Updates

• Last Update Posted (Actual): February 20, 2026
• Last Update Submitted That Met QC Criteria: February 13, 2026
• Last Verified: January 1, 2026

More Information

Terms related to this study

• Other Study ID Numbers: 7363

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No