Myocardial Mass Determination by FFRct and Absolute Coronary Blood Flow
Condition: Fractional Flow Reserve; Absolute Flow Measurement; FFR-CT; Myocardial Mass; Coronary Artery Disease
MeSH terms: Coronary Artery Disease
Study type: Observational

Summary: 
      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: 
      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.
    

Intervention name(s): absolute blood flow measurement
Intervention type(s): Diagnostic Test
Intervention description(s): 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.
Observational model: Cohort
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        Sixty patients will be included who are scheduled

          1. Either for multivessel FFR/PCI fulfilling the following criteria and not meeting any
             of the exclusion criteria (prospective group)

          2. Or patients in whom both coronary CT scanning and invasive exams have been performed
             already for clinical reasons and of whom "complete data" are available already
             (retrospective group)