Seems like I spent most of the month of October thinking about fetal echos in one form or another. Apart from the earlier release of the Fetal Echo Z-Scores: Femur Length calculator, I also developed a couple of "helper" routines:
- A calculator to cross-check the femur length against the EGA derived from dates. Also Gives reference values for fetal thoracic circumference:
Fetal Biometry
- A remake of the CHOP calculator- useful for describing the hemodynamic status of the recipient twin in twin-twin transfusion syndrome (TTTS). Good stuff for reminding me about the various manners in which heart failure can be categorized by fetal echo:
CHOP Fetal CV Profile Score
- A calculator for fetal LV/RV/IVS wall thicknesses. In the absence of any published z-score equations, these two sources (one uses autopsy data) seem to be our only recourse:
Fetal Ventricular Wall Thickness Reference Values
Additionally, the October 13 issue of Circulation brought a new fetal echo z-score reference:
Predictors of technical success and postnatal biventricular outcome after in utero aortic valvuloplasty for aortic stenosis with evolving hypoplastic left heart syndrome.
McElhinney DB, Marshall AC, Wilkins-Haug LE, Brown DW, Benson CB, Silva V, Marx GR, Mizrahi-Arnaud A, Lock JE, Tworetzky W.
Circulation. 2009
Oct 13;120(15):1482-90. Epub 2009 Sep 28.
- Z-Score equations for fetal mitral valve, left ventricle, aortic valve, ascending aorta, and right ventricle are included. The ParameterZ.com z-score calculator is here:
Fetal Echo Z-Scores: Boston Data
- The Smackdown, pitting the established equations from London against these 'new' equations, is here:
Fetal Echo Z-Score Smackdown: Boston vs. Royal Brompton
I won't attempt an analysis beyond the smackdown itself because, as the authors reveal, these new z-score equations are based on
unpublished fetal norms…
Still, it is interesting (to me) to see the data published at all, and I think the smackdown sheds some interesting light on the two groups of equations.
