Intra- and infrahepatic agenesis of the inferior vena cava with azygos continuation accompanied by duplication of the postrenal segment

Congenitally interrupted inferior vena cava without other features of the heterotaxy syndrome: report of five cases and characterization of a rare entity

Congenital interruption of the inferior vena cava (IVC) due to absence of its hepatic segment is usually found in patients with polysplenia. The occurrence without other features of the heterotaxy syndrome is rare, and the frequency of associated additional vascular and cardiac anomalies in these patients is not well known. We reviewed the literature and present 5 of our own patients to characterize this entity. All but 1 of the 67 known cases had visceroatrial situs solitus. There was 1 patient with interruption of the IVC in complete situs inversus. The interrupted IVC typically continued via the azygos system into the superior vena cava, but there were 4 cases without a direct connection between the infrahepatic IVC and the azygos system. Additional venous abnormalities or cardiac malformations were present in 47.8% and 31.4%, respectively. In contrast to the classical heterotaxy syndrome, heart defects with interrupted IVC and normal situs did not involve inversion of cardiac segments. The diagnosis can readily be made by echocardiography or magnetic resonance imaging. Failure to recognize this anomaly can result in various problems during invasive medical or surgical procedures. In our own patients, interventional procedures failed, necessitating an operation in all 5 cases. Careful analysis of systemic venous drainage should be performed in all patients prior to cardiac catheterization, pacemaker implantation, or surgery, even if the visceroatrial situs is normal.

Approach to the educational opportunities provided by variant anatomy, illustrated by discussion of a duplicated inferior vena cava

Variant anatomy recognized during routine cadaveric dissection in the first year of medical school offers great learning potential by allowing students to gain enhanced understanding of an array of important subjects. It provides a framework for reviewing common morphology and embryogenesis of the structure in question, and through the help of appropriate faculty, yields insight into the potential medical, radiologic, and surgical implications. The frequency of clinically important anatomic variation is high enough to allow the gross anatomy laboratory to serve as an excellent teaching platform in this regard. Through anatomy, the student is introduced to the concept of patient individuality, and to the individualization of medical and surgical therapies. Recently, one of the variations encountered in our lab was a duplicated inferior vena cava. We describe our approach to such findings through a systematic discussion of the anatomy and embryology, as well as the radiologic and clinical correlates.

The value of ultrasonography in interrupted inferior vena cava with azygos continuation

The cardiosplenic syndromes represent a complex set of abnormalities of the thorax and viscera resulting from abnormal folding of the embryo during early development. Anomalies of venous development include interruption of inferior vena cava (IVC), and in combination with situs inversus referred to as the polysplenia syndrome. We present a 23-year-old male previously diagnosed as having a persistent left IVC on venography whereas ultrasonographic examination clearly demonstrated interrupted IVC with azygos continuation along with situs inversus.