CONGENITAL stenosis of the pulmonary artery branches is an anomaly characterized by narrowed segments of one or more of the main or peripheral branches of the pulmonary artery. Such conditions lhave been variously labeled pulmonary coaretation,' peripheral pulmonary stenosis,2 and multiple peripheral stenoses 3 of the pulmonary artery. Several cases of this anomaly have appeared in the literature 1-17 since its first description by Oppenheimer4 in 1938. The problems produced by stenosis of the branches of the pulmonary artery are related to diagnosis and to the difficulties that they may present in the correction of associated cardiovascular defects.It is the purpose of this paper to review our experience with 18 cases of steniosis of the pulmonary artery branches (cases 1 to 18) encountered at the Mayo Clinic with particular regard for diagnosis in the presence of infundibular or valvular pulmonary stenosis and for the role of branch stenosis in the surgical therapy of associated cardiovascular abnormalities.
Cases Studied and Procedures UsedTen of the 18 patients were males, and eight were females. Eight patients were 3 years old or less, six were 5 to 10 years old, and four were 17 to 21 years of age. A complete history and physical examination, roentgenogram of the thorax, and electrocardiogram were obtained in each case.Sixteen patients underwent special investigation that utilized cardiac catheterization for From the Mayo Clinic and Mayo Foundation, Rochester, Minnesota.
1 The inotropic effect of Bay K 8644 has been studied in rat and guinea-pig atria and ventricular strips stimulated at I Hz, in a medium containing CaC12 1.8 mM. The positive inotropic effect at maximal effective concentrations of Bay K 8644 was in the following order: guinea-pig ventricle > rat ventricle > guinea-pig atria >> rat atria. 2 In rat preparations, the tension recorded at maximum effective concentrations of Bay K 8644 was similar at three different calcium concentrations (0.7, 1.8, 3.0mM). The amplitude of the positive inotropic effect evoked by Bay K 8644 increased when atrial and ventricular contractions were reduced by lowering the external calcium concentration. 3 The contractile tension reached in the presence ofmaximum effective concentrations of Bay K 8644 (3 x 10-7 -1 x 10-6 M) was greater than that produced by the maximum effective concentration of external calcium (3 mM) in rat ventricles but not in rat atria. 4 High doses of nifedipine (3 x 10--l x 10-6 M) depressed the contraction of rat atria more than the contraction of rat ventricles.
5In rat ventricles, nifedipine shifted to the right the inotropic dose-effect curve of Bay K 8644. 6 It is concluded that the interaction between nifedipine and Bay K 8644 occurred at the same binding sites. These sites have some characteristics of the low affinity binding sites of nifedipine and other related dihydropyridines.
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