Reporting MFR in Clinical Practice*

Report MFR any time MFR adds value toward diagnosis or stratificationBe cautious reporting MFR when MFR provides no diagnostic or prognostic value, might confuse management, or might lead to unnecessary tests
Normal perfusion, high normal MFRHistory of conditions known to impair long-term microvascular function
Abnormal perfusion with more severely or diffusely reduced MFR than expectedChronic renal failure
Microvascular measurements specifically requestedPrior coronary artery bypass grafting
Assessment of hemodynamic significance of lesion specifically requestedGlobal left ventricular dysfunction (suspected cardiomyopathy)
Accurate MFR measurement not possible or might be misleading
Large prior myocardial infarction
Suspected caffeine/methylxanthine ingestion
  • * Adapted from Juneau et al. (178).

  • Depending on experience of lab and understanding of MBF and MFR concepts of referring provider, it may be appropriate to not report findings under these circumstances to avoid confusion and potentially unnecessary subsequent testing.