A clinical appraisal of different Z-score equations for aortic root assessment in the diagnostic evaluation of Marfan syndrome

Genet Med. 2013 Jul;15(7):528-32. doi: 10.1038/gim.2012.172. Epub 2013 Jan 10.

Abstract

Purpose: Aortic sinus diameter dilatation expressed as a Z-score >2.0 is diagnostic in Marfan syndrome. In addition to the classic equation (Z1) for calculating Z-scores, two new equations were recently introduced (Z2 and Z3).

Methods: We studied the effects of obesity, age, and the absolute cut point of 40 mm on these three equations in 2,674 echocardiographic measurements of 260 patients with Marfan syndrome.

Results: Diameters ≥40 mm were associated with Z1 scores <2.0 in 109 measurements (11.0%; 35 patients), Z2 scores <2.0 in 37 measurements (3.8%; 13 patients), and Z3 scores <2.0 in 24 measurements (2.4%; 11 patients). Mean diameters increased after the 40th birthday: 42.0 (37.3-44.8 mm interquartile range) to 42.5 (39.0-45.0 mm interquartile range; P = not significant) and mean Z1 scores decreased from 3.60 to 2.17 (P < 0.01), whereas Z2 and Z3 scores tended to increase (Z2: 3.04-3.27; Z3: 3.39-3.55; P = not significant for both). Comparing Z-scores between patients with body mass index <25 kg/m² (group A) and those with body mass index ≥25 kg/m² (group B), median Z1 scores differed between groups (Z1 = 3.00 in group A, Z1 = 1.78 in group B; P = 0.012), whereas Z2 (Z2 = 2.82 in group A, Z2 = 2.47 in group B; P = 0.52) and Z3 scores (Z3 = 2.72 in group A, Z2 = 3.12 in group B; P = 0.32) did not.

Conclusion: Z1 scores are inferior to Z2 and Z3 scores in Marfan syndrome. In particular, the Z3 score, correcting aortic sinus diameter for body height, seems excellent.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Age Factors
  • Aorta / diagnostic imaging
  • Aorta / pathology*
  • Body Height
  • Body Mass Index
  • Dilatation, Pathologic / diagnostic imaging
  • Echocardiography*
  • Female
  • Humans
  • Male
  • Marfan Syndrome / pathology*
  • Marfan Syndrome / physiopathology
  • Marfan Syndrome / surgery
  • Models, Cardiovascular*
  • Obesity / physiopathology
  • Sinus of Valsalva / physiopathology
  • Young Adult