Z-Score Calculation | The Marfan Foundation

Z-Score Calculation

Different methods are used for aortic root dilatation in different publications (eg.diastolic versus systolic measurement, inner to inner or leading edge to leading edge diameters). One should take into account these differences when choosing a formula to calculate Z-scores. Aortic root refers to the measurement at the sinuses of Valsalva.

Aortic Root Z-Scores for Children

For patients up to 25 years of age: utilizing systole, inner to inner edge measurement of the sinuses of valsalva according to Colan SD et al. J Am Coll Cardiol 2006;47:1858–65)

Height (cm) :

Weight (kg) :

BSA : 0.00

Ao Root at sinuses of Valsalva (in cm) :

Aortic Root Z-Scores for Adults

For patients > 15 years of age through adulthood: utilizing diastole and leading edge-to-leading edge measurement of the sinuses of valsalva according to Devereux RB et al. Am J Cardiol 2012;110:1189 –1194).

Male Female

Height (cm) :

Weight (kg) :

Age (years) :

BSA : 0.00

Ao Root at sinuses of Valsalva (in cm) :

Z-Score: 0
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Adult Z-Score References:

1. Prevalence and Correlates of Aortic Root Dilatation in Normotensive and Hypertensive Adults: The Family Blood Pressure Program. Circulation 2009;120 (suppl 2):s540. Richard B Devereux, Richard Cooper, Alan Weder, Todd B Seto, Craig Hanis, Thomas H Mosley, Jr, D C Rao, Donna K Arnett.

2. Aortic Nomograms. Devereux RB et al. Am J Cardiol 2012;110:1189 –1194.


Children Z-Score References:

1. Theoretical and empirical derivation of cardiovascular allometric relationships in children. J Appl Physiol 99:445-457, 2005. Sluysmans T and Colan SD.

2. Regression Equations for Calculation of Z Scores of Cardiac Structures in a Large Cohort of Healthy Infants, Children, and Adolescents: An Echocardiographic Study. J Am Soc Echocardiogr 2008;21:922-934. Pettersen MD, Du W, Skeens ME, Humes RA.

3. For children ages 2-18, using leading edge to leading edge during diastole (includes aortic wall thickness). 

  • Nomograms for Aortic Root Diameters in Children Using Two-Dimensional Echocardiography. Am J Cardiol 2010 105: (6) 888-894. Gautier M, Detaint D, Fermanian C, Aegerter P, Delorme G, Arnoult F, Milleron O, Raoux F, Stheneur C, Boileau C, Vahanian A, Jondeau G.

  • Dan Dyar, Pediatric Cardiac Sonographer, has created a website that includes several convenient z-score calculators. A calculator that uses this formula can be found here: http://parameterz.blogspot.com/2010/03/aortic-root-diameters.html

4. Marfan syndrome in children and adolescents: an adjusted nomogram for screening aortic root dilation. Heart 1998;78:69–72. Rozendaal L, Groenink M, Naeff MS, Hennekam RC, Hart AA, van der Wall EE, Mulder BJM.