ABSTRACT
A 16‐month‐old intact male Selkirk Rex cat was referred for recurrent hematuria, dysuria, and oliguria. Cystitis with a bladder calculus was diagnosed, and an incidental finding of a splenocaval extrahepatic portosystemic shunt with malformation of the left hepatic vein was discovered. Computed tomographic angiography demonstrated the left hepatic vein crossed the diaphragm, coursed along the left side of the caudal vena cava, and drained into the right atrium. Cellophane banding of the portosystemic shunt was performed. An anomalous left hepatic vein is extremely rare in humans, and this is the first report of such an anomaly in the veterinary literature.
Keywords: computed tomography, coronary sinus, left hepatic vein, portosystemic shunt, vascular anomaly
This study describes a rare anomalous left hepatic vein, crossing the diaphragm and draining into the coronary sinus, coexisting with a splenocaval extrahepatic portosystemic shunt. This condition was diagnosed using computed tomographic angiography in a Selkirk Rex cat, a phenomenon previously unreported in the veterinary literature.
1. Signalment, History, and Clinical Findings
A 16‐month‐old, intact male, Selkirk Rex cat weighing 3.0 kg was presented with recurrent hematuria, dysuria, and oliguria for the previous year. Physical examination and auscultation of the heart and lungs were normal. A complete blood cell count and serum chemistry panel performed 2 weeks before the referral revealed hyperammonemia (500 µmol/L; reference interval [RI] 23–78 µmol/L), hyperglycemia (197 mg/dL, RI 71–148 mg/dL), azotemia with an elevated blood urea nitrogen (107 mg/dL, RI 17.6–32.8 mg/dL) and creatinine (4.45 mg/dL, RI 0.8–1.8 mg/dL), and increased inorganic phosphorus levels (10 mg/dL, RI 2.6–6 mg/dL). The patient underwent 3 days of hospitalization at the local clinic before referral, and a complete blood cell count and serum chemistry panel performed at that time revealed only mild hyperammonemia (102 µmol/L; RI 23–78 µmol/L) upon presentation.
2. Imaging, Diagnosis, and Outcome
Right lateral and ventrodorsal radiographs of the thorax and abdomen were obtained (DRGEM VXR, Gwangmyeong), and bilateral renomegaly (renal length/second lumbar length = 3.5) was identified. On the right lateral thoracic radiograph, a thin linear soft tissue opacity was observed coursing parallel with the caudal vena cava (CVC) (Figure 1). The thickness of the linear soft tissue opacity was 1.3 mm, and it was not visualized on the ventrodorsal image. On abdominal ultrasound (GE VIVID T9, Chicago, Illinois), bilateral renal calculi and a bladder calculus, which were not visible on the radiographs, and cystitis were identified. An anomalous vessel with a diameter of 1.2 mm, showing hepatofugal flow, was identified in the left hepatic lobe. The vessel was found to be arising from the hepatic vein and coursing toward the thoracic cavity through the diaphragm (Figure 2). Poorly developed intrahepatic portal veins (PVs) were observed, and there was a small ratio between the luminal diameters of the PV and the CVC (PV/CVC = 44%) [1]. Subsequent computed tomographic angiography (CTA) was performed with a 16‐multidetector row system (GE Revolution ACT, Chicago, Illinois) to assess the course of the abnormal vessel. A dose of 900 mgI/kg of 300 mg/mL Iohexol (Omnipaque, Ge Healthcare, Chicago, Illinois) was administered intravenously at a rate of 1.0 mL/s, with 20‐, 45‐, and 90 s delays following contrast administration. The images were reconstructed into slice thicknesses of 0.625 mm. Maximal intensity projection and 3D volume rendering images were made. All acquired images were uploaded and reviewed using a picture archiving and communication system (Infinitt PACS, Infinitt Healthcare, Seoul). CTA revealed an anomalous vessel coursing left of the CVC in the thoracic cavity. The vessel was identified as the left hepatic vein (LHV), which crossed the left side of the diaphragm separate from the caval foramen. It coursed left to the CVC to connect with a mildly dilated coronary sinus and drained into the right atrium (Figure 3). In addition, an extrahepatic splenocaval portosystemic shunt (PSS), bilateral renal calculi, a bladder calculus, and an intrapelvic urethral calculus were identified. An echocardiogram performed after the CTA scan revealed a mildly dilated coronary sinus but did not identify the entry point of the LHV into the coronary sinus. Cardiac function was within the normal range on echocardiography. There were no significant findings on an electrocardiogram.
FIGURE 1.
Right lateral thoracic radiograph of the patient. A thin linear soft tissue opacity (arrows) coursing parallel with the CVC is seen. The thickness of the linear soft tissue opacity was 1.3 mm, and the linear soft tissue opacity could not be visualized on the ventrodorsal image.
FIGURE 2.
Sagittal ultrasound image of the left liver lobe of the patient. An anomalous vessel with a diameter of 1.2 mm arising from the LHV and coursing toward the thoracic cavity through the diaphragm is identified (arrows).
FIGURE 3.
Dorsal (A) and sagittal (B) postcontrast CTA images from 45 s delayed phase in a soft tissue algorithm (400 window width, 40 window level) and a three‐dimensional volume rendered image (C) showing the anomalous vessel. The images show the LHV (arrows) coursing left and ventrally to the CVC (arrowheads) and draining into the coronary sinus (asterisks).
The day after the CTA scan, cellophane banding of the PSS, biopsy of the liver parenchyma, and cystostomy for bladder calculus removal were performed. During surgery, the LHV was confirmed to run independent of the CVC and pass through another defect in the diaphragm left of the caval foramen (Figure 4). Histopathology of the liver revealed hepatic lobular atrophy with portal vein hypoplasia, and the bladder calculus was found to be 100% ammonium urate. No recurrence of the PSS and no changes in the LHV malformation were observed during a 10‐month follow‐up period. The patient's cystitis persisted; however, mild improvement was noted.
FIGURE 4.
Intraoperative image of the patient showing the anomalous LHV (arrow) crossing the left side of the diaphragm. The patient's abdominal wall corresponds to the dorsal side of the image, and the patient's left side corresponds to the right side of the image. In the image, the liver is located on the dorsal side of the anomalous LHV (arrow), and the LHV is crossing the left side of the diaphragm.
3. Discussion
In humans, an anomalous connection of the LHV with the coronary sinus has been reported in only a few case reports [2, 3, 4, 5, 6, 7, 8, 9, 10, 11]. Based on our review of the literature, this is the first report of such an anomalous vascular connection in the veterinary literature. This anomaly is characterized by a single vessel arising from the left hepatic lobe and passing through the diaphragm to drain into the coronary sinus and the right atrium [12]. Most cases are incidentally identified during a diagnostic imaging assessment [4, 6] or surgery [7, 12]. This anomaly is usually asymptomatic and has no hemodynamic or clinical significance; however, radiologists should report its occurrence as it has surgical implications if the patient is undergoing cardiac, vascular, or hepatic procedures [5, 10].
The coexistence of a splenocaval portosystemic shunt and LHV anomaly in the present patient may be attributed to a shared embryologic etiology. Anomalous venous connections from the left liver lobe to the coronary sinus may be explained by the persistence of the left vitelline vein with the sinus venosus. Both the left and right horns of the sinus venosus receive blood from the common cardinal vein, the umbilical vein, and the vitelline vein [13]. During gestation, the connection between the sinus venosus and both umbilical veins and the left vitelline vein degenerates. As the veins of the left horn regress, the right horn and right vitelline vein enlarge, forming the CVC and part of the intrahepatic veins. The left horn forms the coronary sinus when the left common cardinal vein is obliterated. Persistence of the left vitelline vein may result in an abnormal venous connection between the liver and the coronary sinus [7, 8, 13]. Similarly, congenital extrahepatic portosystemic shunts result from abnormal communication between the embryonic vitelline veins, which develop into the entire extrahepatic portal system, and the cardinal veins, which develop into the nonportal abdominal veins. This anomalous communication leads to the formation of a shunting vessel between the portal vein or its contributors and the caudal vena cava or azygos vein [14]. Given that both conditions appear to arise from the abnormal persistence or miscommunication of embryonic venous structures, the presence of a splenocaval portosystemic shunt alongside the LHV anomaly in the present case may suggest a shared embryological disruption during the development of the vitelline and cardinal venous systems.
Similar to human studies, the present case showed anomalous LHV with an extrahepatic PSS. Most human case reports describe this anomalous LHV with other cardiovascular malformations, such as persistent left superior vena cava [2, 3, 5, 9, 11], duplication of the superior vena cava [5], inferior vena cava connection with the azygos vein [5], subaortic valve stenosis [4], anomalous pulmonary venous drainage [8], and atrial and ventricular septal defects [9, 12]. Thus, radiologists should screen for anomalous connections of the LHV with the coronary sinus in patients with cardiovascular malformations. In addition, further studies about the prevalence of the anomalous left hepatic venous connection with the coronary sinus and its concurrence with other cardiovascular malformations are needed.
In humans, there are a few diagnostic imaging modalities used to evaluate anomalous connections of the LHV with the coronary sinus. Among them, CTA with multiplanar reconstruction is the gold standard in the diagnosis of anomalous LHV drainage because it is noninvasive, provides a complete evaluation of the great vessels, and can detect other cardiovascular malformations that may be associated with the anomaly [4]. In humans, echocardiography can detect this vascular malformation [6, 8] and is particularly useful in patients with contraindications for CTA. A previous study reported that gradual inspection of the coronary sinus on echocardiography detected the ostium of the LHV joining the dilated part of the coronary sinus perpendicularly [8]. However, in the present case, this echocardiographic technique was unable to identify the entry point of the LHV into the coronary sinus due to the small diameter of the vessel and patient intolerance. This inability to visualize this area may have been further influenced by more limited acoustic windows with narrow fields of view in veterinary patients compared with humans, as well as by reverberation artifacts from the lung, likely exacerbated by the relatively long distance between the diaphragm and the heart compared with humans.
In humans, this vascular anomaly should have no hemodynamic or clinical significance. However, its possible association with atrial arrhythmias has been suggested, as an enlarged coronary sinus may affect the configuration or the function of the conduction system of the heart [2]. In the present case, there were no significant findings on electrocardiography, which may be due to the minor dilation of the distal coronary sinus.
The limitations of the present case study include a lack of macroscopic findings of the connection between the LHV and the coronary sinus. In addition, transesophageal echocardiography was not performed, which may have helped in the visualization of the anomalous LHV in the thoracic cavity and of the entry point of the LHV into the coronary sinus.
In conclusion, an anomalous connection of the LHV to the coronary sinus is very rare, and based on our review of the literature, this is the first published report of such an anomaly in the veterinary literature. CTA is the gold standard modality for the diagnosis of this type of anomalous connection. As an anomalous LHV is most commonly incidentally found during the diagnosis of other cardiovascular malformations, radiologists should screen for an anomalous connection of the LHV in patients with other cardiovascular malformations undergoing CTA examination. This malformation is usually asymptomatic and has no hemodynamic or clinical significance; however, as its possible association with atrial arrhythmia has been suggested, radiologists should report this anomaly. Furthermore, electrocardiography should be performed in affected patients undergoing cardiac, vascular, or hepatic surgery.
List of Author Contributions
Category 1
Conception and design: Park, Noh, Lee, Lee
Acquisition of data: Park
Analysis and interpretation of data: Park, Noh, Lee
Category 2
Drafting the article: Park
Reviewing article for intellectual content: Park, Noh, Lee, Lee
Category 3
Final approval of the completed article: Park, Noh, Lee, Lee
Category 4
Agreement to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved: Park, Noh, Lee, Lee
Conflicts of Interest
The authors declare no conflicts of interest.
Ethics Statement
Animal Usage Guidelines were followed for the study.
Previous Presentation or Publication Disclosure
The authors have nothing to report.
Equator Network Disclosure
The EQUATOR network checklist was not used.
Data Availability Statement
The data that support the findings of this study are available from the corresponding author upon reasonable request.
References
- 1. D'Anjou M. A., Penninck D., Cornejo L., and Pibarot P., “Ultrasonographic Diagnosis of Portosystemic Shunting in Dogs and Cats,” Veterinary Radiology & Ultrasound: The Official Journal of the American College of Veterinary Radiology and the International Veterinary Radiology Association 45, no. 5 (2004): 424–437. [DOI] [PubMed] [Google Scholar]
- 2. Bunger P. C. and Parke W. W., “Persistent Left Hepatic Venous Connection With the Coronary Sinus,” Anatomical Record 203, no. 1 (1982): 189–196. [DOI] [PubMed] [Google Scholar]
- 3. Bhatti S., Hakeem A., Ahmad U., Malik M., Kosolcharoen P., and Chang S. M., “Persistent Left Superior Vena Cava (PLSVC) With Anomalous Left Hepatic Vein Drainage Into the Right Atrium: Role of Imaging and Clinical Relevance,” Vascular Medicine 12, no. 4 (2007): 319–324. [DOI] [PubMed] [Google Scholar]
- 4. Buehler M., Abdullah A., and Lewis T. J., “Left Hepatic Vein and Persistent Left Superior Vena Cava Drainage Into the Coronary Sinus With Subaortic Valve Stenosis,” International Journal of Angiology 20, no. 04 (2011): 243–246. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 5. Milisavljević M., Marinković S., Radak D., ĆEtković M., Vuĉurević G., and Trifunović D., “Duplication of the Superior Vena Cava Associated With Atrial Termination of the Left Hepatic Vein,” Phlebology 28, no. 7 (2013): 369–374. [DOI] [PubMed] [Google Scholar]
- 6. Lee C. and Saremi F., “Anomalous Left Hepatic Vein Draining Into Coronary Sinus Imaged With Multidetector Computed Tomography,” Clinical Anatomy 26, no. 8 (2013): 987–989. [DOI] [PubMed] [Google Scholar]
- 7. Morshuis W. G., de Lind van Wijngaarden R. A., Kik C., and Bogers A. J., “Drainage of the Left Hepatic Vein Into the Coronary Sinus, a Rare Intraoperative Finding,” Journal of Cardiac Surgery 30, no. 11 (2015): 817–818. [DOI] [PubMed] [Google Scholar]
- 8. Karolczak M. A., Mądry W., and Zacharska‐Kokot E., “Anomalous Connection of the Left Hepatic Vein to Coronary Sinus in a Child With PAPVD. Surgical Significance and Diagnostic Difficulties,” Kardiochirurgia i Torakochirurgia Polska 13, no. 1 (2016): 49–51. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 9. Rao R. K., Varadaraju R., Girish B., and Singh N., “Anomalous Left Hepatic Vein to Coronary Sinus in a Patient With Atrial Septal Defect: Minimally Invasive Approach; Technical Challenges,” Journal of Cardiac Surgery 36, no. 11 (2021): 4390–4392. [DOI] [PubMed] [Google Scholar]
- 10. Suzuki A., Uchida H., Ozawa H., and Katsumata T., “Isolated Left Hepatic Vein Draining Into the Coronary Sinus: A Rare Anomaly Encountered During Mitral Valve Surgery,” European Heart Journal ‐ Case Reports 7, no. 5 (2023): 1–2. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 11. Zdravkovic R., Redzek A., Vickovic S., et al., “Isolated Persistent Left Superior Vena Cava Associated With Anomalous Left Hepatic Vein Drainage Into the Right Atrium Accidentally Discovered After Sternotomy,” Kardiologia Polska 81, no. 7–8 (2023): 788–789. [DOI] [PubMed] [Google Scholar]
- 12. Vuran C., Ozker E., Gumus B., and Turkoz R., “Anomalous Hepatic Vein Draining Into the Coronary Sinus,” Pediatric Cardiology 32 (2011): 1256–1257. [DOI] [PubMed] [Google Scholar]
- 13. Cornillie P. and Simoens P., “Prenatal Development of the Caudal Vena Cava in Mammals: Review of the Different Theories With Special Reference to the Dog,” Anatomia, Histologia, Embryologia 34, no. 6 (2005): 364–372. [DOI] [PubMed] [Google Scholar]
- 14. Payne J. T., Martin R. A., and Constantinescu G. M., “The Anatomy and Embryology of Portosystemic Shunts in Dogs and Cats,” Seminars in Veterinary Medicine and Surgery (Small Animal) 5, no. 2 (1990): 76–82. [PubMed] [Google Scholar]
Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Data Availability Statement
The data that support the findings of this study are available from the corresponding author upon reasonable request.