Morphometric study of the human fetal heart I. Arterial segment

Abstract

This study measured the dimensions of the great arteries of normal human fetal hearts at an early fetal stage (between 13-20 weeks post-fertilization) in 103 fetuses obtained by necropsy. Different segments of the aorta and the pulmonary artery were dissected and their external diameters measured under stereoscopic magnification. All segments showed linear growth during this period of fetal development. Ranges in median values of external diameters associated with the pulmonary artery were: 2.1-4.2 mm for the valve ring; 2.2-4.2 mm for the main pulmonary trunk; 1.2-2.5 mm for the right pulmonary artery; 0.9-2.18 mm for the left pulmonary artery; and 4.0-8.0 mm for the length of the main pulmonary trunk. Similarly, in the aorta, median diameters were: 2.1-4.2 mm for the ascending aorta; 1.92-3.8 mm for the aortic arch; 1.45-3.0 mm for the aortic isthmus; and 1.75 -3.35 mm for the descending aorta. The diameter of the ductus arteriosus ranged between 1.2-2.45 mm. The growth rates of the pulmonary artery and the aorta were similar. The diameter of the ascending aorta was found to be greater than that of the descending aorta and the right pulmonary artery was wider than the left pulmonary artery. In addition, the magnitude of growth in the various aortic segments was different and the ratios obtained between the aortic isthmus and the ascending and descending aortae, ranged between 0.66-0.93. This study provides important morphometric reference information concerning the dimensions and growth of the great arteries of the fetal heart and has clinical application in pediatric cardiac surgery and echocardiography.

Aortic Isthmus and Cardiac Monitoring of the Growth-Restricted Fetus

“…[25][26][27] However, the diameter of the aortic isthmus relative to other vessels is not as small as reported in the animal models. 25 The aortic isthmus has a mean diameter of approximately 1 to 1.5 mm at the end of first trimester, 2 to 2.5 mm at midgestation, 14,[27][28][29] and 4 to 5 mm close to term. 29,30 Despite its important role in the fetal circulation, the aortic isthmus is not essential for in utero fetal survival.…”

Diameter of the ductus arteriosus as a predictor of patent ductus arteriosus (PDA)

“…The same author concluded that the capacity of the vessel grew according to exponential regression from 7.25±2.26 mm 3 to 103.52±13.81 mm 3 . According to Castillo et al [23], in a group of fetuses aged between four and five months, the diameter of the ductus arteriosus was 1.2-2.45 mm. A similar value was reported by Szpinda [29] -he found that the diameter in similarly aged fetuses to be 1.48-2.00 mm.…”

“…Available literature documents growth of the length and diameter of fetal arteries as linear in time [17][18][19][20][21][22][23]. The increase of ductus arteriosus capacity is described as exponential in time and following a regression curve [24][25][26].…”

Embryonic Cardiac Morphometry in Carnegie Stages 15–23, from the Complutense University of Madrid Institute of Embryology Human Embryo Collection

“…However, ultrasound probes are only able to obtain foetal cardiac morphometric data from the 10th week of development [Smrcek et al, 2006] and can also only measure the foetal myocardial thickening from the 25th week of gestation [Kunii et al, 2006]. The morphometric analysis of the great arteries could serve as useful predictor of gestational age, when growth retardation was suspected [Castillo et al, 2005]. During embryonic stages, ultrasound techniques can only determine cardiac beat, which is part of the standard ultrasound examination protocol during the 7th week of pregnancy.…”