Aortic Root Z-Scores

Use this calculator to determine z-scores for the aortic valve and aortic root (sinus of Valsalva), using data from Boston Children's Hospital.
Per the authors, the technique used is: "Aortic annulus and root diameters were measured from parasternal long-axis images, with the aortic root diameter taken as the maximum dimension at the level of the sinuses... measured at the maximum systolic dimensions, from inner edge to inner edge."
Body surface area is calculated by the method of Haycock et al.

Also see: consolidated aortic root z-score calculator

Site Measurement Mean Range Z-Score Percentile


Validation and re-evaluation of a discriminant model predicting anatomic suitability for biventricular repair in neonates with aortic stenosis. Colan SD, McElhinney DB, Crawford EC, Keane JF, Lock JE. J Am Coll Cardiol. 2006 May 2;47(9):1858-65.

Previous Comments

On Thursday Feb 07 2008, DIANE HITCHCOCK said:

excellent and very easy to use!! I wish you had z-scores for LVID and LA in pediatrics

On Thursday Feb 07 2008, Dan said:

Thanks! As far as z-scores for the LV and LA- stay tuned. I am working on something that I think is going to work. In the meantime, try this

On Thursday Feb 14 2008, Kathy R. said:

Thank you for doing this; it's very helpful. The reference you provide, though, is for neonates with borderline LV size. Although I can get a z-score for whatever I put in, I wonder if your normative data extend to older children & teenagers. It's not just extrapolated from the babies, is it? Also, do you have any references for (or will you be adding) sinotubular jct. & AAo msmts, especially in older children? Thanks again for all your work.

On Thursday Feb 14 2008, Dan said:

Kathy: Thanks for your comments. As far as the z-scores relating to the population, it is my understanding that the authors provided us with the prediction equations for their normative data, as indicated by: ... on the basis of normative data obtained at our institution from children with structurally and functionally normal hearts [16]) were used instead ... To answer your other question about z scores for other measurement sites, this is the same question I have been asking... is only a small part of the answer.

On Thursday Feb 21 2008, Tim said:

No adjustment for age? This is not stratisfied according to sex either. Both of these have been shown to be main predictors of Aortic root size. See Roman and Devereux to determine your REAl z score. If you are an adult male over 40 years old the mean is 3.4cm +/- 0.3. Tis program understates by a healthey amount.

On Thursday Feb 21 2008, Dan said:

Questions about the cited study design and conclusions drawn (or not drawn) from the results should probably be directed to the authors (and not me). I am simply presenting the findings of the study relevant to the calculation of z-scores. Otherwise, if your are doubting the correctness or accuracy of the calculations themselves as presented here, please let me know. Thanks for the lead on the "Roman and Devereux" studies- I'll read up.

On Thursday Feb 21 2008, Dan said:

*later that same hour* regarding Roman and Devereux: The 1989 Am J Cardiol study is not a fair comparison to the data THIS calculator is based upon (2006 JACC) Roman et al. measured: using "leading edge technique", in diastole, using c.1989 equipment. The JACC 2006 study measured inside edge to inside edge, in systole (when the root is largest), using modern high resolution equipment. Further, Roman et al. studied what was then referred to as a"large sample size"-- 52 infants and children. The Boston data is based on "496 normal children and young adults" and is further based upon a theoretical and empirically derived allometric relationship. I maintain there is no comparison. It might be noteworthy to add that Roman and Devereux are both involved in the Marfan/losartan clinical trail, whose data will be normed, undoubtedly, using aortic root z-score data from Boston- the latest publication of which is represented here. Your mileage may vary.

On Tuesday Mar 18 2008, Tim said:

The problem is that aortic root diameters are measured as were done in Roman. This is the methedology used in almost all Cardilogist office. Thus these values could be confusing to some individuals if they are looking at their echo report!!!

On Tuesday Mar 18 2008, Dan said:

Great point Tim. One of the lessons I have learned about standardized scores is: technique is important! My entire focus with all of these z-score calculators is to provide reference information for pediatric echo, and as such, some of these calculations may not be relevant for other practice areas. If you are not using the same measurement technique as was used in the reference article, the z-scores will obviously not apply.

On Wednesday Apr 30 2008, M. said:

Wow. I'm not sure this is accurate? I mean, I've been plotting mine on the chart from my cardiologist and this calculator gives me a huge score!

On Thursday May 01 2008, Dan said:

@ "M.": Are you questioning the veracity of the calculations themselves, or the application of the calculations?

On Thursday May 29 2008, Nayana Parange said:

thank you for the calculators--I was wondering if you are aware of any data regarding fetal aortic root ultrasound measurements? cheers, Nayana

On Thursday May 29 2008, Dan said:

Nayana: I am personally unaware of any published z-score equations for the fetal aortic root, but wish you great luck in finding them.

On Thursday May 29 2008, Nayana said:

thanks for your prompt reply, Dan.

On Thursday Jun 12 2008, Maria Lapoint said:

Gracias por existir!

On Tuesday Jul 08 2008, Courtney L.Anthony, MD said:

Very useful

On Tuesday Jul 29 2008, JoAnn Puccella said:

At duPont Hospital for Children in Wilmington, DE we measure the Ao at the annulus, sinus, junction and ascending. Are z-scores acailable for those locations?

On Tuesday Jul 29 2008, Dan said:

JoAnn: The recent data from Michigan gets you z-scores for everything except the AAO, if you are comfortable with their model. Published equations for Z-Scores of the AAO are indeed rare.

On Friday Aug 01 2008, Bob Todd said:

nice, thanks

On Friday Aug 29 2008, Rejane said:

I got a few referrals for suspicion of fetal dilatation of the ascending aorta on routine ultrasound. We only find Z scores for the aortic annulus, but not for the supravalvar aorta, sinotubuluar junction and ascending aorta. Is there a source I'm not aware of? thanks so much for your help. I love these calculators you provide, keep up the good stuff... Rejane

On Friday Aug 29 2008, Dan said:

Rejane: Thanks for your comments. The calculator on this page will only calculate z-scores of the annulus and sinuses of valsalva ("aortic root"). ANOTHER calculator will give you z-scores for the annulus, sinuses, and ST junction. You are not mistaken- neither one has data for the AAO... I have yet to find a published source for AAO z-score equations.