Correlation Study of Imaging Data Acquired During CABG With Data Acquired in the Cath Lab
Condition: Coronary Artery Disease
MeSH terms: Coronary Artery Disease
Study type: Interventional

Summary: 
      Visual assessment of a coronary artery narrowing (called stenosis) seen on angiography is
      conventionally used to infer how likely the stenosis will limit blood flow (called ischemia)
      under conditions of increased demand (e.g exercise). This is based on animal work and data
      from humans with simple single vessel disease with no co-existing conditions. These data have
      been extrapolated to more complex patients/ complex disease but clearly over-simplifies the
      situation in the majority of patients cardiologists treat.

      Pivotal work by DeBruyne, Pils and colleagues in the 90's convincingly showed that pressure
      derived measurements, called FFR, from the coronary artery during a cardiac catheterization,
      more accurately identify stenoses that would cause ischemia compared to visual assessment
      alone. A strategy of FFR guided coronary stenting with drug eluting stents significantly
      improved outcomes and reduced costs compared to visual assessment alone (FAME trial).
      Deferring treatment based on FFR has been shown to be safe (DEFER Trial). FFR has excellent
      sensitivity and specificity. A FFR of <=0.80 was used as this identified ischemia causing
      lesions 90% of the time. Therefore, the concept of FFR guided percutaneous revascularisation
      and treatment deferral has a robust evidence base to support it.

      Coronary bypass grafting (CABG) is traditionally based solely on a visual assessment of
      angiography images. SPY® Infrared Fluorescence Angiography (NIRF, FDA approved 2005) is used
      by some cardiac surgeons to assess the patency of bypass grafts in real-time in the operating
      room, as a surrogate for immediate traditional coronary angiography. Dr. Ferguson observed
      that regional myocardial perfusion (RMP) image data was also captured in these video
      sequences.

      Study Hypotheses:

        1. In patients who are likely CABG candidates, target vessel epicardial coronary arteries
           (TVECAs) with FFR > 0.80 will not demonstrate an increase in RMP despite an anatomically
           patent bypass conduit during SPY® imaging.

        2. In TVECAs with an increase in RMP during SPY® imaging, cardiac catheter laboratory
           measures of coronary physiology from that TVECA, namely one or a combination of FFR,
           CFR, HSR and HMR, will correlate with the SPY® data on myocardial perfusion, and suggest
           a potential mechanism for this physiologic response to TVECA grafting.
    


Intervention name(s): ComboMap XT Guidewire; 'SPY' NIRF During CABG
Intervention type(s): Device; Procedure
Intervention description(s): Intracoronary pressure and flow measurements; FDA approved use of injection of indocyanine green for the purposes of performing pre and post coronary grafting graft patency and perfusion assessment with the SPY near infra red fluorescence system
Intervention model: Single Group Assignment
Intervention model description: Controlled prospective observational study
Masking: None (Open Label)
Primary purpose: Diagnostic
Keywords: Fractional Flow Reserve (FFR); Instantaneous Wave Free Ratio (iFR); Coronary Flow Reserve (CFR); Hyperemic Stenosis Resistance Index (HSR); Hyperemic microvascular resistance (HMR); Wave intensity analysis (WIA); Myocardial Perfusion; SPY NIRF Regional Myocardial Perfusion Analysis