An 83-year-old man with an infrarenal abdominal aortic aneurysm, asymptomatic coronary artery stenosis, and hypertension presented for elective open abdominal aortic aneurysm surgery. Cardiac catheterization demonstrated 50% stenosis of the left anterior descending artery. The preoperative electrocardiogram revealed complete right bundle-branch block and left axis deviation with premature ventricular contractions. The transthoracic echocardiogram was consistent with normal left-ventricular systolic function and grade 1 diastolic dysfunction. No abnormalities of the heart and great vessels were detected. Transesophageal echocardiography (TEE) was considered for intraoperative monitoring of ventricular function and detection of myocardial ischemic changes. After anesthetic induction and tracheal intubation, the TEE probe (X7-2t transducer; Philips Healthcare, Andover, MA) was inserted into the esophagus. A routine TEE examination demonstrated normal global and regional left-ventricular function and normal valvular function. During examination of the right side of the heart, anomalous insertion of the inferior vena cava (IVC) into the right atrium (RA) was detected. A midesophageal (ME) bicaval view at the multiplane 93° angle revealed that the IVC was inserted into the lateral free wall of the RA at an oblique angle (Fig. 1A) (see Supplemental Digital Content 1 and 2, Video 1, http://links.lww.com/AA/A265, and Video 2, http://links.lww.com/AA/A266; see Appendix for video captions). Pulse Doppler flow profile demonstrated a venous flow pattern (Fig. 1B). When the TEE probe was advanced, turned farther clockwise, and rotated by 45° for examination of the IVC at the hepatic level, the IVC was seen to be bent at an obtuse angle with the right hepatic vein (RHV) joining it at the point of the bend. The IVC proximal to the bend and the RHV were in a straight line relative to each other (Fig. 2) (see Supplemental Digital Content 1, Video 1, http://links.lww.com/AA/A265). Furthermore, a 3-dimensional (3D) full-volume image based on the ME bicaval view was reconstructed for further evaluation. Anomalies of the IVC and surrounding tissue were simultaneously demonstrated (Fig. 3) (see Supplemental Digital Content 2, Video 2, http://links.lww.com/AA/A266). In this case, anomalous insertion of the IVC did not affect the surgical procedure. The operative course was uneventful, and the patient was discharged from the hospital 10 days later.
Congenital anomalies of the junction between the IVC and the RA are rare. Takeda et al.1 reported 2 cases associated with this anomaly. The first was a 2-year-old cyanotic boy with complex cardiac anomalies, including dextrocardia, single right ventricle, truncus arteriosus, tricuspid atresia, atrial septal defect, and persistent left superior vena cava associated with this anomaly. In that case, venography showed the opening of the IVC into the posterior wall of the RA at an anomalous high position. The second case was that of a 10-month-old boy with levocardia and transposition of the great arteries. In that case, the IVC was located to the left of the spine and showed anomalous high insertion into the posterior wall of the atrium. Kursaklioglu et al.2 reported a case of anomalous high insertion of the IVC into the posterior wall of the RA in a 20-year-old asymptomatic man. Thus, although a few cases have been reported demonstrating anomalous insertion of the IVC into the RA, there is no report about anomalous IVC insertion on the lateral side of the RA. Furthermore, TEE diagnosis of this anomaly has never been reported.
When examining anomalous venous connection to the RA free wall, 2 potential differential diagnoses should be considered: anomalous pulmonary venous connection, and anomalous hepatic venous connection directly to the RA. Partial anomalous pulmonary venous connection is not that uncommon; it is found in 0.4% to 0.7% of autopsies. Anomalous pulmonary venous connection to the RA was identified in 12.1% of all patients with partial anomalous pulmonary venous connection.3 In such cases, the anomalous venous return originated from the right-sided pulmonary vein. Furthermore, sinus venosus atrial septal defect was the most common associated anomaly in 49% of patients.3 Morphologic finding of the IVC connecting to the RA from an infracardiac site and absence of the pulmonary vein insertion into the left atrium (LA) would be a decisive diagnostic, not of an anomalous IVC insertion, but of an anomalous pulmonary venous return in such cases. A pulse Doppler flow profile might also help the differentiation. The flow profile of the pulmonary vein is characterized by a biphasic pattern of the systolic wave segment, whereas IVC flow is characterized by a retrograde wave between the systolic and diastolic wave. However, these characteristics do not always exist and both venous flow profiles are often similar. Hence, differentiation would be difficult on the basis of flow characteristics alone. In our case, although the Doppler flow profile was not characteristic of the IVC (Fig. 1B), the diagnosis was made on the basis of the morphologic information of continuity of the IVC from the hepatic site and normal insertion of the right pulmonary veins into the LA (Fig. 3) (see Supplemental Digital Content 2, Video 2, http://links.lww.com/AA/A266). Another possible differential diagnosis of anomalous venous connection to the RA free wall is direct hepatic vein connection into the RA.4 In one such case in which the suprarenal segment of the IVC was absent, a dilated azygos vein drained into the superior vena cava and hepatic veins drained into the RA via a single channel. The anomaly represents one of the characteristics of the polysplenia syndrome.5 In that case, differentiation was done by observation of the morphologic characteristics, namely, the existence of the intrahepatic IVC and insertion of the RHV into the IVC at the hepatic level.
While using a 2D TEE to view the area inferior to the RA up to the level of the liver, the transition from ME to transgastric view is often accompanied by a transient loss of image quality, potentially because of impedance changes. This often makes exact delineation and interpretation of the venous structures challenging. However, 3D technology might be able to scan these structures as 1 frame and help the interpretation of these morphologic relationships, because of the broader scan angle and observation from various angles.
TEE is useful for examining the opening of the IVC into the RA, the IVC at the hepatic level, and the junction of the hepatic vein and the IVC. Use of TEE examination to prevent malpositioning of the venous cannula into the hepatic vein during cardiopulmonary bypass (CPB) has been described.6 The venous cannula is most likely to be inadvertently placed in the RHV because it is the largest of the 3 hepatic veins and enters the IVC at an oblique angle. In our patient, the IVC was connected to the lateral wall of the RA across from the fossa ovalis and bent at the hepatic level, where the RHV joined the IVC. Furthermore, the IVC and RHV were in a straight line. Although anomalous insertion of the IVC into the RA and the relative positioning of the IVC and RHV with respect to each other had no clinical implications for the patient in this case, if this patient had presented for CPB, there could have been potential problems, especially with venous cannulation. It is highly possible that the IVC cannula would be malpositioned in the RHV via the RA wall at the time of IVC cannulation, in case of the need for bicaval cannulation. Single 2-stage cannulation of the IVC might increase this risk. Also, there might be a potential risk of venous perforation if cannulation is performed too aggressively. On the other hand, in case of femoral venous cannulation, the guidewire and cannula would be directed toward the atrial septum, leading to the risk of opening the fossa ovalis and/or perforation of the atrial septum and cannulation of the LA. In such situations, TEE would be useful for guiding cannula placement.
Our experience in this case recommends vigilance about such anomalies in all patients presenting for cardiac surgery with CPB, because anomalous placement of the IVC is asymptomatic and is only diagnosed as an incidental finding, as in this case. Intraoperative identification of this malposition by TEE might prevent potentially serious complications during CPB.
1. Takeda K, Matsumura K, Ito T, Nakagawa T, Yamaguchi N. Anomalous insertion of the superior or inferior vena cava into the right atrium. Pediatr Cardiol 1998;19:474–6
2. Kursaklioglu H, Celik T, Iyisoy A, Kose S. Anomalous high insertion of the inferior vena cava into the right atrium: a case report with review of literature. Congenit Heart Dis 2006;1: 127–8
3. Ammash NM, Seward JB, Warnes CA, Connolly HM, O'Leary PW, Danielson GK. Partial anomalous pulmonary venous connection: diagnosis by transesophageal echocardiography. J Am Coll Cardiol 1997;29:1351–8
4. Beedie RJ, Yeo W, Morcos SK. Congenital absence of the intrahepatic segment of the inferior vena cava with azygos continuation presenting as a mediastinal mass. Postgrad Med J 1989;65:253–5
5. Ruscazio M, Van Praagh S, Marrass AR, Catani G, Iliceto S, Van Praagh R. Interrupted inferior vena cava in asplenia syndrome and a review of the hereditary patterns of visceral situs abnormalities. Am J Cardiol 1998;81:111–6
6. Kirkeby-Garstad I, Tromsdal A, Sellevold OF, Bjørngaard M, Bjella LK, Berg EM, Karevold A, Haaverstad R, Wahba A, Tjomsland O, Astudillo R, Krogstad A, Stenseth R. Guiding surgical cannulation of the inferior vena cava with transesophageal echocardiography. Anesth Analg 2003;96:1288–93
APPENDIX: VIDEO CAPTIONS
Video 1. A midesophageal bicaval transesophageal echocardiographic (TEE) view at the multiplane 93° angle demonstrated anomalous connection of the inferior vena cava (IVC) into the right atrium (RA). The IVC was inserted into the lateral free wall of the RA at an oblique angle. Color flow Doppler profile demonstrated the inflow from the IVC into the RA. A transgastric view with clockwise and 45° rotation of the TEE probe demonstrated the IVC and the right hepatic vein (RHV). The IVC was bent at an obtuse angle (white line) and the RHV joined it at the point of the bend. The IVC proximal to the bend and the RHV were in a straight line relative to each other (red line). SVC = superior vena cava.
Video 2. A 3-dimensional (3D) full-volume–based midesophageal bicaval transesophageal echocardiographic view shown from the anterior and left anterolateral sides of the heart and the transgastric position demonstrated anomalous insertion of the inferior vena cava (IVC) into the lateral wall of the right atrium (RA) at an oblique angle, opposite to the foramen ovale, and normal insertion of both right pulmonary veins into the left atrium (LA). A 3D full-volume–based transgastric view demonstrated the IVC and the right hepatic vein (RHV). The IVC was bent at an obtuse angle (white line). SVC = superior vena cava; FO = foramen ovale; RUPV = right upper pulmonary vein; RLPV = right lower pulmonary vein.
Clinician's Key Teaching Points By Martin M. Stechert, MD, Roman M. Sniecinski, MD, and Martin J. London MD
- The normal anatomic relationship of the insertion of the intrahepatic segment of the inferior vena cava (IVC) inferiorly into the right atrium (RA) is in a longitudinal, cranial-caudal axis with the superior vena cava (SVC). Variations of IVC anatomy have been reported including IVC duplication, interruption of IVC with azygos continuation, and anomalous high IVC insertion into the RA. The latter involves connection to the RA laterally, with abnormal angulation of the normal SVC-RA-IVC axis.
- Variation on IVC anatomy is most commonly noted during interventional radiology and cardiac catherization procedures using IV contrast, but can also be seen using transesophageal echocardiography (TEE). From the midesophageal bicaval view, the probe is advanced with small adjustments of the multiplane angle to track the course of the intrahepatic IVC and view the insertion of the 3 hepatic veins: right, middle, and left. Much like the pulmonary veins, the hepatic veins can be interrogated with pulsed wave Doppler to provide information on RA pressure or severity of tricuspid regurgitation.
- In this case of a patient with an abdominal aortic aneurysm, routine TEE imaging noted the IVC connected to the RA lateral wall at an oblique angle. Intrahepatic continuation of the hepatic tributaries was confirmed using 2 dimensional (D) and 3D imaging. Potential differential diagnoses including partially anomalous pulmonary vein drainage and direct hepatic vein insertion to the RA were excluded.
- Recognition of isolated anomalous insertion of the IVC to the RA is potentially important as it may pose a risk during venous cannulation for cardiopulmonary bypass. During standard cannulation of the RA with a dual stage cannula, loss of the cranial-caudal SVC-RA-IVC axis could theoretically predispose to atrial perforation. Conversely, with femoral cannulation for fem-fem bypass, abnormal angulation into the RA could direct the cannula towards the intraatrial septum with potential for RA perforation.