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NCT Number: NCT04420325

COronary and MICrocirculatory Measurements in Patients With Aortic Valve Stenosis.

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.

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Key information

Conditions

Aortic Stenosis Aortic Valve Disease Aortic Valve Stenosis Arterial Occlusive Diseases Arteriosclerosis Cardiovascular Diseases Coronary Artery Disease Coronary Disease Heart Diseases Heart Valve Diseases Myocardial Ischemia Vascular Diseases Ventricular Outflow Obstruction

Age range

18 year and older

Sex eligibility

All sexes

Study type

Observational

Primary location

UZ Leuven, Leuven, Vlaams-brabant, Belgium

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About this study

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

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

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.
  • The patient has an intermediate (50-90%) coronary lesion that requires further evaluation.
  • The patient undergoing the procedure is male, or if female, has no childbearing potential or is not pregnant.

Exclusion criteria

  • The procedure is an emergency and/or the patient is unstable.
  • Pregnancy or lactation
  • Haemodynamically unstable patients
  • Killip class III-IV heart failure
  • Previous coronary artery by-pass in the artery being assessed
  • Contra-indications for adenosine administration: severe asthma or pre-existing type 2 AV-block
  • No significant coronary artery disease (<50% stenosis on angiography).
  • Critical coronary artery disease deemed by the Heart Team to require immediate revascularization
  • 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.

Treatment and study plan

Primary outcomes

  1. 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.

Secondary outcomes

  1. 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.

  2. 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.

Sponsors and collaborators

Lead sponsor

Universitaire Ziekenhuizen KU Leuven

Other

Collaborators

  • AZ Delta
  • University Hospital, Antwerp

Registry information

Official study title

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

Acronym: COMIC-AS

Important dates

Study start
2020
Primary completion
2024
Study completion
2024
First posted
Jun 9, 2020
Registry last updated
Sep 5, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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