Anomalous origin with and without crossing of the pulmonary arteries

Abstract

Dear Editors, We would like to thank the authors Newman and Alkhori [1, 2] for the excellent two-part review concerning congenital anomalies of the central pulmonary arteries. The articles synthesize and illustrate a wide range of pulmonary artery abnormalities. It is a relevant subject whose current and systematic approach facilitates the readers’ understanding. Crossed pulmonary arteries was one of the anomalies reviewed. We would like to illustrate this condition, expand its definitions and, perhaps, rectify some concepts reported by the authors. Crossed (or crisscross) pulmonary arteries is a subtype of malposition of the branch pulmonary arteries [3]. This category of anomalies is believed to result from a counterclockwise rotation of the pulmonary trunk or the origin of the pulmonary arteries [4]. Malposition of the branch pulmonary arteries is a rare anomaly (corresponding to 0.33% of congenital heart diseases [5]) with, to date, 87 reported cases (the 88th case is reported in this letter; see Fig. 1 and Online Supplementary Material 1 for a summary of all cases found in the English literature). Malposition of the branch pulmonary arteries is divided into (a) without crossing (14.8% of cases), (b) with typical crossing (84.1%) and (c) with atypical crossing (1.1%) of the pulmonary arteries (Fig. 2) [3, 4, 6, 7]. Malposition of the branch pulmonary arteries without crossing has an anomalous origin of the pulmonary arteries in such a way that the left emerges from the pulmonary trunk just above the right pulmonary artery and there is no crossing [3, 6]. Malposition of the branch pulmonary arteries with typical crossing (or crossed pulmonary arteries) features an anomalous origin of the pulmonary arteries, in which the ostium of the left pulmonary artery lies superior and to the right to the ostium of the right pulmonary artery [3, 4, 6]. In turn, the right pulmonary artery originates superior and leftward to the contralateral pulmonary artery in the malposition of the branch pulmonary arteries with atypical crossing [7]. There is an intersection of the central branch pulmonary arteries in both malposition of the branch pulmonary arteries with typical and atypical crossing in a pre-tracheal situation and, therefore, a vascular ring does not develop [3, 4, 6, 7]. Malposition of the branch pulmonary arteries is usually accompanied by congenital heart disease, of which ventricular septal defects (48.8% of cases; Online Supplementary Material 1), atrial septal defects (43.2%) and conotruncal defects (38.6%) are the most recurrent. Newman and Alkhori [2] claimed that malposition of the branch pulmonary arteries is commonly associated with left pulmonary artery stenosis; however, such stenosis was described in only one case [5, 8]. A significant portion is associated with some syndrome or mutation (27.3% of cases), among which the main one is DiGeorge syndrome (22q11 deletion) [5, 8]. The anomalous origin of the pulmonary arteries (with or without crossing) by itself does not imply significant hemodynamic repercussions; however, its recognition should lead to the investigation of associated congenital anomalies, such as screening for 22q11.2 microdeletion [3–5, 8]. * André Vaz [email protected]