Do any of you use the FRIEND predicted equations for CPET in clinical populations? How about with heart failure or heart transplant qualification?
If you do use the FRIEND equations have you used them since your lab has been in operation or have you transitioned from other reference equations?
If you were to start a new CPET lab would you use FRIEND or Wasserman-Hansen equations?
The thresholds for normality, risk stratification, and transplant qualification will vary according to which standards are used (see Brawner et al 2020 below). In starting a new CPET lab that will be serving a wide range of clinical populations, including heart transplant candidates, I am leaning to the Wasserman-Hansen equations. It is widely used, so the reports will be more portable, and the percent predicted will be more appropriate for transplant qualification.
What do you think? Any comments would be appreciated. Thanks!
-Brian
"...any adoption of new normative references should only occur after thorough consideration of how they might affect clinical decisions. For instance, we previously showed that in patients with heart failure and reduced ejection fraction, the classification of these patients into risk categories (eg, high risk associated with ppVO2max <50%) can vary greatly depending upon the equation used to predict normal VO2max. Considering that the vast majority of studies of peak VO2 and survival in patients with heart failure have used the Wasserman-Hansen equations, the ppVO2max associated with a target absolute survival (eg, 60% survival at 2 years) must be determined before adopting a new reference. Interestingly, current heart failure guidelines statements do not address which reference equation is preferred."
Brawner CA, Ehrman JK, Keteyian SJ. Are International Standards for Exercise Capacity Ready for Prime Time? Mayo Clin Proc. 2020 Feb;95(2):218-220.