Myocardial Mass Determination by FFRct and Absolute Coronary Blood Flow

Study Overview
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Brief Summary
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The background for performing the present study is to compare the mass calculations by CT scanning and by invasive absolute blood flow measurements and thereby corroborating both methods.

Detailed Description
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Although knowledge about the myocardial mass (in grams) of the different territories belonging to the major coronary arteries, is of clinical importance to estimate risk of coronary interventions (PCI, CABG) and to determine area of necrosis after myocardial infarction, no invasive methodology has been available so far for reliable assessment of mass. Especially in the setting of percutaneous coronary intervention (PCI), it would be valuable to have information about the absolute and relative myocardial mass distal to the location where the intervention is planned. Such information is valuable for risk estimation and can also be helpful in multivessel disease to determine the most adequate way of revascularization. Both MRI and CT scanning have claimed to be able to estimate myocardial mass non-invasively, but by the lack of any gold standard, none of these methods could be validated in vivo so far. A relatively new development in CT technology is the calculation of fractional flow reserve (FFR) by CT scanning, according to a sophisticated algorithm developed by Heartflow Inc. One of the baseline assumptions in that algorithm is that myocardial mass is proportional to resting blood flow, which seems a plausible assumption from a rational physiological point of view. More recently, invasive calculation of absolute blood flow has become possible as well as resistance measurement of the (microcirculation of the) myocardium. Using that invasive technology (explained in the appendix to this protocol), it can be assumed that measuring absolute maximum blood flow in a coronary artery as well as fractional flow reserve for different territories or for different spots within one major coronary artery, provides a basis for relative mass calculation. The background for performing the present study is to compare these mass calculations by CT scanning and by invasive measurements, thereby corroborating both methods.

Official Title
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Myocardial Mass Determination of the Different Coronary Territories by FFRct and Invasive Measurement of Absolute Coronary Blood Flow. A Clinical Registry

Conditions
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Fractional Flow Reserve, Absolute Flow Measurement, FFR-CT, Myocardial Mass, Coronary Artery Disease

Intervention / Treatment
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* Diagnostic Test: absolute blood flow measurement


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Presence of multivessel coronary disease with an indication for multivessel FFR and/or PCI or patients with single vessel disease scheduled for FFR/PCI of that single coronary artery Availability of a coronary CT scan performed prior to the scheduled invasive investigation. The time difference between the CT scan and the invasive exam should be less than 3 months. Focal lesions only Normal left ventricular function Age < 75 years Note: previous uncomplicated PCI in any of the coronary arteries is permitted Exclusion Criteria: Inability to give informed consent Diffuse coronary disease Tortuous or calcified arteries interfering with reliable invasive FFR assessment Previous myocardial infarction or ejection fraction less than 60% by echocardiography or ventriculography or less than 50% by nuclear methods Atrial fibrillation interfering with high quality coronary CT scanning Contra-indications for CT scanning Left main stenosis Age > 75 years Pregnancy or desired pregnancy in the future

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 75 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Intervention/Treatment |
| --- |
|Diagnostic Test: absolute blood flow measurement|Absolute maximum flow will be measured, using the RayFlow® multifunctional monorail infusion catheter. (This measurement takes a few minutes per artery, does not require any additional drug, but only 50-100 ml of saline per artery, and is not associated with any additional risk for the patient compared to the regular invasive procedure.|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Comparison of Mass and flow | To compare relative myocardial mass distribution (i.e. mass of the respective territories of LAD, LCX and RCA) by CT scanning to normalized hyperemic blood flow in the three major myocardial territories as assessed by absolute flow measurements and FFR in patients with an indication for multivessel FFR measurement. | 3 months | 
| Comparison of Mass and flow in the LAD | To compare relative myocardial mass belonging to a proximal or a mid segment of one of the major coronary arteries measured by CT scanning to invasive absolute flow and FFR measurement in that particular proximal or mid coronary artery in patients undergoing single or multivessel PCI. | 3 months |