AM Report Pearls: Aortic Stenosis Level 200!

*Take-Home Pearl* Aortic stenosis severity is determined mostly by the *mean gradient* & the valve area has an exponential relationship with the mean gradient!

AM Report Pearls: ADVANCED Aortic Stenosis Management:

  • The mean gradient is the most important measurement that determines prognosis: the relationship of AVA to mean gradient is EXPONENTIAL:
  • Rate of progression: Mean annual increase in mean gradient is usually ~3 mm Hg
  • Some patients can have severe AS by valve area but normal gradients and normal AS – in the literature, they call these patients “Low-gradient severe AS”) i.e. LGSAS patients. Causes include:
    • Low-normal or mildly reduced stroke volume in pts with normal LV size & borderline normal LV function ~50%
    • Small LV commensurate with body size yielding a lower stroke vaolume
    • Calculation errors in determining valve area (underestimating LVOT)
    • Concomitant mitral regurgitation which leads to “pseudo-normal” EF and paradoxically low gradients (as in Dan’s patient today)
  • Sometimes for these patients it can be useful to re-calculate valve area and pressure gradients during exercise or during dobutamine stress tests to see how valve areas and cardiac outputs change
    • If dobutamine stress test increases cardiac output & increases valve area, it is likely that our initial TTE calculations overestimated stenosis severity
  • If this sounds complicated, it is! Even the Cardiology community is wrestling with this population of patients and if they are physiologically “different” when it comes to outcomes – see this article:  http://circ.ahajournals.org/content/123/8/838.full
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