Impact of Hyperemic State on Angio-IMR Performance

The Impact of Hyperemic State on the Performance of Angiography Derived Indices in Assessing Coronary Microvascular Disease

The goal of this observational study is to evaluate the diagnostic performance of angiography-derived microcirculatory indices (Angio-IMR) in assessing patients with stable angina or suspected coronary artery disease. The main questions it aims to answer are:

How do the numerical values of Angio-IMR from five different software vendors change across three physiological states (resting, sub-hyperemia induced by nitroglycerin, and maximal hyperemia induced by adenosine)? Which physiological state and software algorithm provide the highest diagnostic accuracy (Area Under the Curve, AUC) for diagnosing Coronary Microvascular Disease (CMD) when compared to the gold standard wire-based IMR? Researchers will compare the Angio-IMR results calculated under the three different physiological conditions within the same patient to see how the hyperemic state impacts the performance and consistency of these non-invasive indices.

Participants will:

Undergo standard-of-care coronary angiography and physiological assessment using a pressure wire for index of microvascular resistance (Wire-IMR) as part of their clinical management.

Have their angiographic images captured at three specific time points: at rest, after intracoronary nitroglycerin, and during adenosine-induced maximal hyperemia.

Allow their de-identified imaging and clinical data to be analyzed by an independent core laboratory using five different Angio-IMR software platforms to evaluate microvascular function.

Study Overview

• Status: Recruiting
• Conditions: Coronary Artery Disease; Microvascular Coronary Artery Disease
• Intervention / Treatment: Diagnostic test: Angiography-derived IMR

Detailed Description

Study Overview and Procedural Protocol

This is a prospective, multi-center, diagnostic accuracy study employing a self-controlled design. All participants will undergo coronary angiography and physiological assessment according to standard clinical indications. During the procedure, specific angiographic images will be systematically captured for the target vessel at three distinct physiological time points:

Resting State: Baseline coronary angiography without any hyperemic agents. Sub-hyperemic State: Following the intracoronary administration of nitroglycerin.

Maximal Hyperemic State: During continuous intracoronary infusion of adenosine to achieve maximal microvascular vasodilation.

Immediately following image acquisition, the reference standard measurement-Wire-IMR-will be performed using a pressure-sensor-equipped guidewire under maximal hyperemia.

Core Laboratory Imaging Analysis and Blinding

All angiographic data will be de-identified and transferred to a centralized, independent Cardiovascular Imaging Core Laboratory at Zhongshan Hospital, Fudan University. The analysis will be conducted as follows:

Software Platforms: Five different commercially available Angio-IMR software platforms (anonymized as A, B, C, D, and E) will be used to calculate microvascular resistance.

Independent Analysis: Five dedicated analysts, each specialized in one specific software platform, will perform the calculations. Each analyst will be blinded to the patients' clinical information, the Wire-IMR gold standard results, and the results from the other four software platforms.

Standardization: A primary researcher, not involved in the software measurements, will pre-define the target vessel segments and measurement frames to ensure consistency across all five software platforms.

Statistical Considerations and Data Management The study aims to determine if the coronary hyperemic state significantly alters the fluid dynamics modeling utilized by Angio-IMR algorithms. AUC will be calculated for each software at each of the three states. A head-to-head comparison of AUCs will be performed using DeLong's test. To maintain data integrity, results from the core laboratory and the clinical centers will remain strictly separated until the final database lock.

• Study Type: Observational
• Enrollment (Estimated): 192

Contacts and Locations

• Study Contact: Name: Jinying Zhou, MD, PhD; Email: zhou.jinying@zs-hospital.sh.cn
• Study Contact Backup: Name: Chenguang Li, MD, PhD; Phone Number: 021 6404 1990; Email: li.chenguang@zs-hospital.sh.cn

Study Locations

• China
  • Guangzhou, China
    • Recruiting
    • The First Affiliated Hospital, Sun Yat-sen University
    • Contact: Xun Hu, MD, PhD; Phone Number: 020-87608185; Email: hxun@mail.sysu.edu.cn
  • Please Select
    • Shanghai, Please Select, China, 200000
      • Recruiting
      • Zhongshan Hospital, Fudan University
      • Contact: Jinying Zhou, MD, PhD; Phone Number: 021 6404 1990; Email: zhou.jinying@zs-hospital.sh.cn

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Probability Sample

Study Population

The study population consists of adult patients (aged 18 and older) clinically diagnosed with stable angina or suspected coronary artery disease who are scheduled to undergo conventional coronary angiography and invasive physiological assessment.

Participants are prospectively and consecutively recruited from multiple clinical centers in China. The population specifically targets individuals with non-obstructive coronary arteries (stenosis < 50%) or those with moderate stenosis (50%-90%) but preserved epicardial flow (FFR > 0.80), where assessment of coronary microvascular function is clinically indicated to investigate the cause of ischemia.

Description

Inclusion Criteria:

• Stable angina or suspected coronary heart disease.
• Scheduled for coronary angiography and physiological assessment.
• Target vessel with stenosis < 50% or 50%-90% with fractional flow reserve (FFR) > 0.80.
• Provided informed consent.

Exclusion Criteria:

• Hemodynamic instability (acute myocardial infarction, cardiogenic shock, severe arrhythmia).
• Contraindications to angiography (e.g., end-stage renal disease).
• Contraindications to adenosine (e.g., severe asthma, high-degree atrial-ventricular block).
• Life expectancy < 1 year or pregnancy.
• Target vessel unsuitable for wire operation (left main lesion, severe tortuosity) or stenosis > 90%.

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort

Intervention / Treatment

Single cohort, self-controlled

Diagnostic test: Angiography-derived IMR; Unlike the reference standard "Wire-IMR," which requires the advancement of a specialized pressure-sensor guidewire into the distal coronary artery, Angio-IMR is a wire-free technology. It derives microvascular resistance indices purely through computational fluid dynamics (CFD) or specialized mathematical models based on standard coronary angiographic projections. This eliminates the risk of wire-induced vascular injury or spasm.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Area Under the ROC Curve (AUC)	Comparison of AUC for 5 types of Angio-IMR against Wire-IMR (Gold standard, CMD defined as Wire-IMR ≥ 25) under three states.	Baseline

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Diagnostic Accuracy	Sensitivity, specificity, positive predictive value, negative predictive value.	Baseline
Correlation	Pearson/Spearman coefficients between Angio-IMR and Wire-IMR.	Baseline
Agreement	Bland-Altman analysis (Bias and Limits of Agreement).	Baseline
Inter-vendor Agreement	Consistency between different software brands.	Baseline

Collaborators and Investigators

• Sponsor: Shanghai Zhongshan Hospital
• Collaborators: First Affiliated Hospital, Sun Yat-Sen University; Zhongnan Hospital; The 7th People's Hospital of Zhengzhou

Study record dates

Study Major Dates

• Study Start (Actual): May 4, 2026
• Primary Completion (Estimated): October 31, 2026
• Study Completion (Estimated): December 31, 2026

Study Registration Dates

• First Submitted: May 11, 2026
• First Submitted That Met QC Criteria: May 21, 2026
• First Posted (Actual): May 29, 2026

Study Record Updates

• Last Update Posted (Actual): May 29, 2026
• Last Update Submitted That Met QC Criteria: May 21, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Keywords: Computational Fluid Dynamics; Coronary Physiology; Index of Microcirculatory Resistance; Angiography-Derived Indices
• Additional Relevant MeSH Terms: Vascular Diseases; Cardiovascular Diseases; Heart Diseases; Arteriosclerosis; Arterial Occlusive Diseases; Coronary Disease; Myocardial Ischemia; Coronary Artery Disease
• Other Study ID Numbers: B2026-265

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

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