COronary and MICrocirculatory Measurements in Patients With Aortic Valve Stenosis. (COMIC-AS)

September 4, 2025 updated by: Universitaire Ziekenhuizen KU Leuven

COronary and MICrocirculatory Measurements in Patients With Aortic Valve, the COMIC AS Study.

Although concomitant coronary artery disease (CAD) is frequent in patients with severe aortic stenosis (AS), hemodynamic assessment of CAD severity in patients undergoing valve replacement for severe AS is challenging. Myocardial hypertrophic remodeling interferes with coronary blood flow and may influence the values of fractional flow reserve (FFR) and nonhyperemic pressure ratios (NHPRs). The aim of the current study is to investigate the effect of the AS and its treatment on current indices used for evaluation of CAD. The investigators will compare intracoronary hemodynamics before, immediately after, and 6 mo after aortic valve replacement (AVR) when it is expected that microvascular function has improved. Furthermore, the investigators will compare FFR and resting full-cycle ratio (RFR) with myocardial perfusion single-photon emission-computed tomography (SPECT) as indicators of myocardial ischemia in patients with AS and CAD. One-hundred consecutive patients with AS and intermediate CAD will be prospectively included. Patients will undergo pre-AVR SPECT and intracoronary hemodynamic assessment at baseline, immediately after valve replacement [if transcatheter AVR (TAVR) is chosen], and 6 mo after AVR. The primary end point is the change in FFR 6 mo after AVR. Secondary end points include the acute change of FFR after TAVR, the diagnostic accuracy of FFR versus RFR compared with SPECT for the assessment of ischemia, changes in microvascular function as assessed by the index of microcirculatory resistance (IMR), and the effect of these changes on FFR. The present study will evaluate intracoronary hemodynamic parameters before, immediately after, and 6 mo after AVR in patients with AS and intermediate coronary stenosis. The understanding of the impact of AVR on the assessment of FFR, NHPR, and microvascular function may help guide the need for revascularization in patients with AS and CAD planned for AVR.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Detailed Description

https://journals.physiology.org/doi/full/10.1152/ajpheart.00541.2021?rfr_dat=cr_pub++0pubmed&url_ver=Z39.88-2003&rfr_id=ori%3Arid%3Acrossref.org

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Observational

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
116

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 Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Contact Backup

Study Locations

  • Belgium
      • Antwerp, Belgium
        • University Hospital Antwerp
      • Roeselare, Belgium
        • AZ Delta
    • Vlaams-brabant
      • Leuven, Vlaams-brabant, Belgium, 3000
        • UZ Leuven

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

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Sampling Method

Non-Probability Sample

Study Population

Patients undergoing routine cardiac catheterization during preparation for TAVI or SAVR, who are found to have coronary artery disease, will be approached to take part.

Description

Inclusion Criteria:

  • 1. Patient undergoing the procedure is older than 18 years, has severe aortic valve stenosis (according to ESC guidelines) and is planned for cardiac catheterization as part of the pre-operative (SAVR) or pre-percutaneous (TAVI) work up.

    2. The patient has an intermediate (50-90%) coronary lesion that requires further evaluation.

    3. The patient undergoing the procedure is male, or if female, has no childbearing potential or is not pregnant.

Exclusion Criteria:

  1. The procedure is an emergency and/or the patient is unstable.
  2. Pregnancy or lactation
  3. Haemodynamically unstable patients
  4. Killip class III-IV heart failure
  5. Previous coronary artery by-pass in the artery being assessed
  6. Contra-indications for adenosine administration: severe asthma or pre-existing type 2 AV-block
  7. No significant coronary artery disease (<50% stenosis on angiography).
  8. Critical coronary artery disease deemed by the Heart Team to require immediate revascularization
  9. Patients will be excluded from the SPECT study (secondary objective) if they have a left main coronary stenosis >50%, triple vessel disease, previous myocardial infarction in the same coronary artery & tandem lesions (separated by >10mm) requiring independent evaluation in the same coronary artery since these factors interfere with the SPECT analysis.

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

  • Observational Models: Cohort
  • Time Perspectives: Prospective

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
FFR 6 Months After SAVR/TAVI.
Time Frame: 6 months

Aortic valve intervention can potentially result in a change in fractional flow reserve (FFR) 6 months after SAVR/TAVI.

FFR is the ratio of two intra-coronary measurements (Distal coronary pressure divided by proximal coronary pressure) and can range from 0.0-1.0.

A lower FFR means that the lesion is more severe and therefore a higher FFR is considered better. The threshold to speak about hemodynamic significant of a lesion is 0.80. If the lesion has an FFR of ≤ 0.80 means the lesions is significant and treatment is necessary.
6 months

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
IMR 6 Months After SAVR/TAVI.
Time Frame: 6 months

Measurement of IMR in patients with AS prior to intervention and 6 months after TAVI/SAVR.

IMR is unitless and gives a description of coronary microvascular resistance, it can range from 0-100.

Lower values are considered better as they are related with better microvascular function and health.

If the IMR > 25 we say microvascular dysfunction is present and treatment is considered necessary.
6 months
FFR Versus RFR to Determine Ischemia.
Time Frame: Baseline

Comparison of the diagnostic performance of FFR versus RFR compared with SPECT ischemia.

The higher the Area under the curve the better. The range is 0.0-1.0. An area under the curve for a ROC model is considered excellent if > 0.8.
Baseline

Collaborators and Investigators

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

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Universitaire Ziekenhuizen KU Leuven

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
University Hospital, Antwerp
AZ Delta

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Christophe Dubois, MD, PhD, UZ Leuven

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.

Helpful Links

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)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
June 1, 2020

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
April 1, 2024

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
October 1, 2024

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
June 3, 2020

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
June 3, 2020

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
June 9, 2020

Study Record Updates

Last Update Posted (Estimated)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
September 5, 2025

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
September 4, 2025

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
June 1, 2025

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • S63740

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

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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