THE RESTRICTED SURGICAL RELEVANCE OF MORPHOLOGIC CRITERIA TO CLASSIFYSYSTEMIC-PULMONARY COLLATERAL ARTERIES IN PULMONARY ATRESIA WITH VENTRICULAR SEPTAL-DEFECT

Now that systemic-pulmonary collateral arteries are used for unifocali zation in patients with pulmonary atresia and ventricular septal defec t, the question arises whether morphologic criteria of these collatera l arteries could help to provide better results. In an attempt to clas sify the morphologic features of systemic-pulmonary collateral arterie s, we studied 31 heart-lung autopsy specimens with pulmonary atresia a nd ventricular septal defect. The course of the systemic-pulmonary col lateral arteries (origin, branching pattern, and connections with syst emic and central pulmonary arteries) was related to their histologic c haracteristics. The results show that systemic-pulmonary collateral ar teries cannot be classified according to their course related to the t rachea and the main branches of the bronchi. The histologic features o f these collateral arteries vary along their course to the lungs. Near ly all systemic-pulmonary collateral arteries contain a muscular or a musculoelastic segment. One type of collateral artery (complex loop an astomoses) is completely muscular and resembles a bronchial artery. Nu tritive branches (bronchial arteries) arise from all histologic types of systemic-pulmonary collateral artery segments. The size and number of intimal proliferations in muscular, elastic, and musculoelastic seg ments did not differ significantly. In 29 of 31 cases a ductus arterio sus did not coexist with large collateral arteries (two cases unknown) . It is concluded that a classification of large systemic-pulmonary co llateral arteries based on morphologic features results in a highly va riable system, which does not facilitate decisions for the suitability of these arteries for unifocalization procedures. The variability of the systemic-pulmonary collateral arteries corresponds with the recent embryologic finding that during development, collateral artery format ion is possible during extended periods.