Pennington D W, Gold W M, Gordon R L, Steiger D, Ring E J, Golden J A
Department of Medicine, University of California, San Francisco 94143.
Am Rev Respir Dis. 1992 May;145(5):1047-51. doi: 10.1164/ajrccm/145.5.1047.
Pulmonary arteriovenous malformations (AVM) lead to chronic hypoxemia and systemic emboli. These lesions can now be treated by catheter embolization. In order to examine physiologic abnormalities during exercise in AVM patients, and to evaluate functional improvement after therapeutic embolization, eight patients underwent detailed physiologic studies at rest and during exercise before and after therapeutic embolization. Before treatment, six patients noted dyspnea on exertion and three had symptoms suggesting paradoxical embolism. Resting studies showed hypoxemia, abnormally increased shunt fractions, chronic alveolar hyperventilation, mild decreases in diffusing capacity, and abnormal wasted ventilation (VD). During exercise, oxygenation changed little from the resting values but VD increased markedly. Functional impairment was observed in most patients, and was correlated with shunt fraction. Obliteration of the AVM was accomplished by therapeutic embolization with placement of coils or balloons in the feeder vessels. This treatment resulted in immediate relief of dyspnea and improvement in resting PaO2 and shunt fraction. Exercise studies after embolization showed improvement in exercise capacity and gas exchange. However, chronic alveolar hyperventilation and reduced diffusing capacity remained unchanged. In summary, therapeutic embolization effectively reduces the degree of shunting, with improvement in respiratory symptoms, exercise capacity, and gas exchange at rest and during exercise. The abnormally decreased diffusing capacity and increased VD suggest the presence of a diffuse pulmonary vascular abnormality, of which further study is warranted.
肺动静脉畸形（AVM）可导致慢性低氧血症和全身栓塞。现在这些病变可通过导管栓塞治疗。为了检查AVM患者运动期间的生理异常，并评估治疗性栓塞后的功能改善情况，8例患者在治疗性栓塞前后进行了详细的静息和运动生理研究。治疗前，6例患者运动时出现呼吸困难，3例有提示矛盾栓塞的症状。静息研究显示低氧血症、分流分数异常增加、慢性肺泡过度通气、弥散能力轻度降低以及无效通气（VD）异常。运动期间，氧合与静息值相比变化不大，但VD显著增加。大多数患者观察到功能损害，且与分流分数相关。通过在供血血管中放置线圈或球囊进行治疗性栓塞来闭塞AVM。这种治疗立即缓解了呼吸困难，改善了静息时的动脉血氧分压（PaO2）和分流分数。栓塞后的运动研究显示运动能力和气体交换有所改善。然而，慢性肺泡过度通气和降低的弥散能力仍未改变。总之，治疗性栓塞有效降低了分流程度，改善了呼吸症状、运动能力以及静息和运动时的气体交换。弥散能力异常降低和VD增加提示存在弥漫性肺血管异常，对此值得进一步研究。
