The Re-organization of Circulation in Lungs with Advanced Hypertensive Arteriopathy and Obstructed Vascular Bed. A Computer-aided Reconstruction of Lung Vasculature in Patients with Congenital Heart Disease

对11例先天性心脏病继发肺动脉高压患者的肺进行了肺血管计算机三维重建，以直观地显示血管疾病的分布，了解肺循环是如何通过新形成的侧支重新组织的。动脉病变Heath&Edwards分级3级2例，4级或以上2例。重建显示，低级别患者的动脉床仅部分和不均匀地阻塞，而4级或更高级别的患者动脉床阻塞越来越均匀，这可能是这些患者阻力升高的原因。丛状病变通常发生在从载瘤血管外侧发出的单径动脉；相反，纤维闭塞的动脉在树顶的二分分支中占优势，这表明一些血液动力学因素参与了动脉病变的发病。络脉得以发展，从而以各种方式绕过阻塞性疾病。扩张的病变覆盖了严重狭窄的小动脉段，显示出将部分血液从周围的支气管动脉引向肺泡毛细血管。此外，支气管-肺动脉吻合术被证明存在于更近端的水平，使肺动脉血液绕过梗阻。因此，流向肺泡组织的血液主要通过两种途径维持，一种是通过丛状病变内含的微小通道和内膜增厚，另一种是通过“旁路”侧支，这些侧支将肺动脉的血液引向支气管动脉。

Computered 3-D reconstruction of pulmonary vessels was performed on lungs from eleven patients with pulmonary hypertension secondary to congenital heart diseases, in order to visualize the distribution of vascular diseases and understand how the pulmonary circulation is re-organized by newly formed collaterals. Arteriopathy was within grade 3 of Heath ＆ Edwards classification in two patients, while in the others it was grade 4 or higher. Reconstruction disclosed that patients of lower grade had an arterial bed which was only partially and unevenly obstructed, whereas those of grade 4 or higher had increasingly uniform obstruction of the arterial bed, and this would account for the elevated resistance in these patients. Plexiform lesions were shown to develop usually in a monopodial artery arising laterally from a parent vessel; in contrast, fibrously occluded arteries prevailed in dichotomous branches at the treetops, suggesting some haemodynamic factors involved in the pathogenesis of arteriopathies. Collaterals were demonstrated to develop so as to bypass in various ways the obstructive diseases. The dilatation lesions, overriding a severely stenosed arteriolar segment, were shown to lead some of the blood away from the peripheral bronchial arteries and to the alveolar capillaries. Also, broncho-pulmonary arterial anastomosis proved to exist at more proximal levels, allowing pulmonary arterial blood to circumvent the obstruction. Thus the blood flow to the alveolar tissue is mainly sustained via two pathways, one through the minute channels contained in the plexiform lesions o intimal thickenings and the other, via "bypass type" collaterals which lead pulmonary arterial blood along the bronchial arteries.