Normal values of the growth of the pulmonary arteries in children. An angiography study

Systolic and diastolic diameters of the pulmonary artery anulus (PA-A), pulmonary artery sinus (PA-S), pulmonary artery trunc (PA-St), as well as those of the right and left pulmonary arteries (RPA, LPA) were measured from cineangiograms of 51 infants, children and adolescents without heart disease (n = 16) or with cardiovascular malformations which had no hemodynamic relevance (n = 35). The following diagnostic categories were included in the normal group: pulmonary stenosis (n = 16), bicuspid aortic valve (n = 4) or subvalvular aortic stenosis (n = 2), all with a systolic gradient lower than 15 mm Hg, aberrant innominate artery (n = 5), small PDA (n = 3) or small VSD (n = 2) and patients with Kawasaki disease without coronary aneurysms (n = 3). The patients were sedated and studied in a fasting state and in the supine position. Angiocardiographies were performed in the right ventricle or/and in the pulmonary artery. A grid or the known diameter of the catheter was used for calibration purposes. The corresponding systolic and diastolic diameter values were averaged in order to obtain a mean diameter of each vascular segment. All measurements were correlated with the body length and the body surface area (BSA). A root exponential function [square root of y = a(1 - e-bx) + c] was used, the regressions coefficients of which can be explained by physiological means. In this function c2 is the theoretical minimal diameter and (a + c)2 the theoretical maximal diameter of a cardiovascular structure; in this way the growth of the cardiovascular dimensions could be well defined mathematically and correlated strongly (r = 0.99) with body length and BSA. Different exponents were found for the pulmonary artery anulus, sinus, trunc as well as right and left pulmonary arteries. All the diameters showed a systolic increase between 8 to 10% above diastolic measurements. The anulus had an average diameter 16% smaller than the sinus and 9% than the distal region of the pulmonary artery; the right pulmonary artery was 7% larger than the left. A limitation of the study was that the diameters were measured in single projections only, necessitating the assumption of a circular cross section of the cardiovascular structures. The angiographically determined PA-A was larger than those of formaldehyd-fixed hearts. This finding indicates that the fixation method may alter the anatomic structures probably due to shrinkage process. PA-S measurements were closest to echocardiographic diameters measured by other authors.