Tweddell James S, Pelech Andrew N, Frommelt Peter C
Division of Cardiothoracic Surgery, Department of Surgery, Medical College of Wisconsin, Milwaukee, WI, USA.
Semin Thorac Cardiovasc Surg Pediatr Card Surg Annu. 2006:147-52. doi: 10.1053/j.pcsu.2006.02.020.
As the velocity of a fluid increases a low-pressure zone is created, this is the Venturi effect and it explains the pathogenesis of aortic valve prolapse (AVP) and aortic insufficiency (AI) that is observed in a subset of patients with a ventricular septal defect (VSD). The VSDs complicated by AI are restrictive with high velocity shunting through the VSD, creating a low-pressure zone that impacts the adjacent aortic valve cusp resulting in AVP and subsequent AI. AVP and AI are therefore acquired lesions. AI is absent at birth because the forces necessary to create the low-pressure zone within the restrictive VSD do not exist in utero. The risk of development of AI increases during childhood, peaking at 5 to 10 years of age. VSD closure eliminates the low-pressure zone that is the cause of ongoing aortic valve cusp deformity and, if performed early, prevents development of AI. Patients with a subarterial VSD and AVP should undergo surgery to prevent the development of AI because this complicates about half of subarterial VSDs with AVP and spontaneous closure is rare. Patients with perimembranous VSDs with AVP should be followed with serial echocardiography and undergo VSD closure if more than trivial AI develops.
随着流体速度增加，会形成一个低压区，这就是文丘里效应，它解释了在一部分室间隔缺损（VSD）患者中观察到的主动脉瓣脱垂（AVP）和主动脉瓣关闭不全（AI）的发病机制。合并AI的VSD具有限制性，高速分流通过VSD，形成一个低压区，影响相邻的主动脉瓣叶，导致AVP及随后的AI。因此，AVP和AI是后天性病变。AI在出生时不存在，因为在子宫内不存在在限制性VSD内形成低压区所需的力量。AI的发生风险在儿童期增加，在5至10岁时达到峰值。VSD闭合消除了导致主动脉瓣叶持续畸形的低压区，如果早期进行手术，可预防AI的发生。患有动脉下VSD和AVP的患者应接受手术以预防AI的发生，因为这会使约一半患有AVP的动脉下VSD病情复杂化，且很少会自发闭合。患有膜周部VSD和AVP的患者应进行系列超声心动图检查随访，如果出现超过轻度的AI则应进行VSD闭合手术。
