Congenital stenosis of the pulmonary artery branches: A classification, with postmortem findings in two cases

Abstract

Stenosis of the pulmonary artery branches may be divided into the following: type I, single central stenosis; type II, bifurcation stenosis; type III, multiple, peripheral stenoses; and type III, combined central and peripheral stenoses. Well over half of the cases are accompanied, and thus frequently masked, by an associated cardiac defect. In these cases the first diagnosis of stenosis of the pulmonary artery branches is usually made either at surgery or in the catheter room, especially if selective angiocardiography is performed. The diagnosis of isolated stenosis of the pulmonary artery branches is to be considered in a patient with evidence of right ventricular preponderance and an atypical, frequently distant, holosystolic, or less often, quasicontinuous murmur in the second intercostal spaces well transmitted to the lungs. On the plain roentgenogram, the lung fields should be searched for vascular dilatations. Fluoroscopy with image amplification may reveal intrinsic pulsations separate from the hilar vessels. At catheterization, wide pulse pressure is noted in the main pulmonary artery; a pressure differential can be measured across the stenotic segments. Usually, confirmation of the diagnosis must await angiocardiography. Some patients apparently tolerale their disease well for years. In others, intimal fibrous proliferation and thrombosis may progressively narrow already stenotic vessels and lead to right ventricular failure. The dilated poststenotic, veinlike pulmonary arteries may become aneurysmal; troublesome, if not fatal, bleeding can follow. Endarteritis is an additional possible complication. In Case IV a reduction in diameter of the right pulmonary artery by two-thirds or more is illustrated which protects the vascular bed of the right lung from medial thickening and intimal proliferation present in the hypertensive vascular tree of the left lung. To date, surgical therapy has been directed to the removal of pulmonary artery ancurysms and to dilatation, widening or resection of the single central type of branch pulmonary artery stenosis. Knowledge of the natural history of isolated stenosis of the pulmonary artery branches and an understanding of the evolution of structural changes in these vessels is yet incomplete.