Quantitative morphology of the left subclavian artery in human fetuses.

PURPOSE The present study was performed to compile normative data for dimensions of the left subclavian artery at varying gestational age. MATERIAL AND METHODS Using anatomical dissection, digital image analysis (Leica Q Win Pro 16 system) and statistical analysis (ANOVA, regression analysis) a range of measurements (length, original external diameter, volume) for the left subclavian artery in 128 spontaneously aborted human fetuses aged 15-34 weeks was examined. RESULTS No significant gender differences were found (P>0.05). The length ranged from 4.62 +/- 0.49 to 12.28 +/- 1.25 mm, according to the linear function y = -2.1482 + 0.4302 x +/- 0.9972 (r = 0.93 P<0.001). The original external diameter increased from 0.68 +/- 0.16 to 2.89 +/- 0.29 mm, according to the linear model y = -1.2169 + 0.1233 x +/- 0.2389 (r = 0.95 P<0.001). The left subclavian artery-to-aortic root diameter ratio increased from 0.337 +/- 0.064 to 0.423 +/- 0.103. Distance between the left common carotid and left subclavian arteries increased from 0.57 +/- 0.17 to 3.92 +/- 0.91 mm. Aortic arch diameter to distance between the left common carotid and left subclavian arteries decreased with advanced fetal age, from 2.82 +/- 0.51 to 1.56 +/- 0.27. The volume ranged from 1.77 +/- 0.89 to 80.60 +/-; 22.18 mm3, in accordance with the quadratic function y = 76.0 - 8.956 x + 0.031 x2 +/- 10.945 (R2 = 0.85). CONCLUSIONS The developmental dynamic of the length and diameter of the left subclavian artery follows a linear regression, whereas its volumetric dynamic follows a quadratic regression. The ratio of the aortic arch diameter to the distance between the left common carotid and left subclavian arteries has clinical application in the early recognition of aortic coarctation.