Advertisement
Mayo Clinic Proceedings Home

In Reply—Revisiting the Historical Origins of Clinically Meaningful Coronary Artery Obstruction

      To the Editor:
      First, I sincerely thank Rosenthal
      • Rosenthal R.L.
      Revisiting the historical origins of clinically meaningful coronary artery obstruction.
      for his correspondence letter regarding my prior editorial.
      • Rumberger J.A.
      Coronary artery disease: a continuum, not a threshold.
      We all continue to learn, and as a student of medical history I am embarrassed that I was not aware of his excellent 2015 commentary on “The 50% Stenosis.”
      • Rosenthal R.L.
      The 50% stenosis.
      In that article, Rosenthal acknowledged the commonly held physiologic studies by Gould et al
      • Gould K.L.
      • Lipscomb K.
      Effect of coronary stenoses on coronary flow and resistance.
      as one of the original investigations on the severity of percent stenosis and coronary hemodynamics; I now stand corrected on the true origins of the clinical use of the 50% stenosis threshold. However, as also noted in my editorial, I suspect that a lot of the future issues of “percent stenosis” relied on the classic hemodynamic studies done by Katz and Linder
      • Katz L.N.
      • Linder E.
      Quantitative relations between reactive hyperemia and the myocardial ischemia which it follows.
      in the 1930s.
      As the use of 50% or more stenosis as possibly suggesting ischemia became popular in the 1960s and 1970s, much of this concept was fostered, legitimized, and perpetuated by studies looking at stress testing, where the sensitivity and specificity values for potential “ischemia” were found to be optimal using the angiographic 50% threshold.
      I did not really state my opinion about the current use of a 70% stenosis as more likely being the standard for fractional flow reserve; on the contrary, I stated the current “expert consensus” using a percent stenosis threshold for “revascularization.” The latest Appropriateness Criteria for Coronary Revascularization in patients with stable ischemic heart disease uses either (1) 70% or more luminal diameter narrowing, by visual assessment, of an epicardial stenosis measured in the “worse view” angiographic projection and/or (2) a fractional flow reserve of 0.80 or less consistent with downstream inducible ischemia.
      • Patel M.R.
      • Calhoon J.H.
      • Dehmer G.J.
      • et al.
      ACC/AATA/AHA/ASE/ASNC/SCAI/SCCT/STS Appropriate use criteria for coronary revascularization in patients with stable ischemic heart disease: a report of the American College of Cardiology Appropriate Use Criteria Task Force, American Association for Thoracic Surgery, American Heart Association, American Society of Echocardiography, American Society of Nuclear Cardiology, Society for Cardiovascular Angiography and Interventions, Society of Cardiovascular Computed Tomography, and Society of Thoracic Surgeons.
      I still get asked questions by patients about “percent stenosis” since this vernacular has now escaped into the public realm. We are still bound in the stenosis world in cardiology. Yet, control of microvascular coronary tone is much more complicated than just looking at the worse narrowing, or percent stenosis, in an epicardial coronary vessel. Thus, it is almost naive to define such a luminal narrowing as exemplifying the nature of coronary blood flow and coronary artery flow reserve. I believe that we need to deal with the physiology of ischemia (whether it is fractional flow reserve determined using computed tomography or traditional fractional flow reserve determined during coronary angiography or just true angina experienced by a patient) and not the anatomy perceived by “stenosis” during visual inspection of an angiogram.
      However, the main focus of my editorial was that atherosclerotic plaque disease is a disorder of the arterial wall, and it escapes detection by coronary angiography (or stress testing or perfusion testing) until it has advanced to be a disorder of the lumen. As I had stated, coronary atherosclerotic disease is a continuum and not a threshold.
      Again, I thank Dr Rosenthal for his correspondence.

      References

        • Rosenthal R.L.
        Revisiting the historical origins of clinically meaningful coronary artery obstruction.
        Mayo Clin Proc. 2017; 92: 1312
        • Rumberger J.A.
        Coronary artery disease: a continuum, not a threshold.
        Mayo Clin Proc. 2017; 92: 323-326
        • Rosenthal R.L.
        The 50% stenosis.
        Am J Cardiol. 2015; 115: 1162-1165
        • Gould K.L.
        • Lipscomb K.
        Effect of coronary stenoses on coronary flow and resistance.
        Am J Cardiol. 1974; 34: 48-55
        • Katz L.N.
        • Linder E.
        Quantitative relations between reactive hyperemia and the myocardial ischemia which it follows.
        Am J Physiol. 1939; 126: 283-288
        • Patel M.R.
        • Calhoon J.H.
        • Dehmer G.J.
        • et al.
        ACC/AATA/AHA/ASE/ASNC/SCAI/SCCT/STS Appropriate use criteria for coronary revascularization in patients with stable ischemic heart disease: a report of the American College of Cardiology Appropriate Use Criteria Task Force, American Association for Thoracic Surgery, American Heart Association, American Society of Echocardiography, American Society of Nuclear Cardiology, Society for Cardiovascular Angiography and Interventions, Society of Cardiovascular Computed Tomography, and Society of Thoracic Surgeons.
        J Am Coll Cardiol. 2017; 69: 2212-2241

      Linked Article