Bandlamudi Manav, Ahmad Mansoor, Mungee Sudhir
Geneva General Hospital
UIC
Aortic valvular atresia is a congenital condition in which the aortic valvular cusps are fused at birth. This condition frequently forms a spectrum of left ventricular outflow tract malformations. The atresia can be characterized as subvalvular, valvular, or supravalvular, depending on the site of the anomaly. The defect commonly presents as aortic stenosis, though it can manifest as complete atresia in rare cases. When atretic, the valve can be dome-shaped, monocuspid, bicuspid, or even quadricuspid, and the associated leaflets are dysplastic or fused, not permitting flow through the abnormal valve. This condition is sometimes but not always associated with congenital ventricular hypoplasia, which can be part of hypoplastic left heart syndrome (HLHS). The left heart and aortic structures are abnormal or underdeveloped in this condition. In HLHS, the mitral valve is often underdeveloped, although there is a universal association with aortic valve abnormalities. Isolated aortic valvular atresia is exceedingly rare, and in context, total aortic valvular atresia can be regarded as the most advanced manifestation of HLHS. In a classic case of aortic valve atresia, there is generally an anatomic connection between the right and left sides of the heart, usually in the form of either a patent foramen ovale, another form of an atrial septal defect, or in cases with a functioning mitral valve, a ventricular septal defect. The right ventricle is generally dilated rather than thickened, and the left ventricle is hypoplastic and thick-walled, much smaller than the right ventricle. The mitral valve has been noted to be usually small, and in some cases, there is associated mitral valve atresia. No pathological case reports in the literature have shown transposition of the great vessels, and the pulmonary trunk typically arises from the right ventricle with appropriate branching. Due to the lack of an aortic valve, the aortic root generally arises from the base of the heart. The coronary arteries arise typically from the aortic root, but the ascending aorta and arch of the aorta are usually hypoplastic. The branches of the aorta are normal in caliber, and all studied cases report a large ductus arteriosus that empties into the descending aorta, providing mixed oxygenated blood for the fetus.
主动脉瓣闭锁是一种先天性疾病，在出生时主动脉瓣叶融合。这种疾病常形成一系列左心室流出道畸形。根据异常部位，闭锁可分为瓣下型、瓣膜型或瓣上型。该缺陷通常表现为主动脉狭窄，不过在罕见情况下可表现为完全闭锁。闭锁时，瓣膜可为圆顶形、单叶、二叶甚至四叶，相关瓣叶发育异常或融合，导致血流无法通过异常瓣膜。这种情况有时但并非总是与先天性心室发育不全相关，后者可能是左心发育不全综合征（HLHS）的一部分。在此情况下，左心和主动脉结构异常或发育不全。在HLHS中，二尖瓣通常发育不全，尽管与主动脉瓣异常普遍相关。孤立性主动脉瓣闭锁极为罕见，从整体来看，完全性主动脉瓣闭锁可视为HLHS最严重的表现形式。在典型的主动脉瓣闭锁病例中，心脏左右两侧通常存在解剖连接，通常为卵圆孔未闭、房间隔缺损的另一种形式，或者在二尖瓣功能正常的情况下为室间隔缺损。右心室通常扩张而非增厚，左心室发育不全且壁增厚，比右心室小得多。二尖瓣通常较小，在某些情况下还伴有二尖瓣闭锁。文献中尚无病理病例报告显示大动脉转位，肺动脉干通常起自右心室并正常分支。由于缺乏主动脉瓣，主动脉根部通常起自心脏底部。冠状动脉通常起自主动脉根部，但升主动脉和主动脉弓通常发育不全。主动脉分支管径正常，所有研究病例均报告有一条粗大的动脉导管汇入降主动脉，为胎儿提供混合的含氧血液。
