Rescue of outflow block of the remnant left liver after extended right hemihepatectomy for resection of a tumor in the caudate lobe.

Outflow block of the liver is a life-threatening event after living donor liver transplantation. Herein, we rescued a patient suffering from the outflow block of the remnant left hemiliver caused by bending of the left hepatic vein (LHV) after right hemihepatectomy plus caudate lobectomy combined with resection of the middle hepatic vein (MHV). A metastatic tumor sized 6 cm in the caudate lobe of the liver involving the root of the MHV was found in a 50's year old patient after resection of a right breast cancer eight years ago. Right hemihepatectomy and caudate lobectomy combined with resection of the MHV was performed using a two-stage hepatectomy (partial TIPE ALPPS). On day 1, the total bilirubin value increased to 4.5 mg/dL, and a dynamic computed tomography (CT) scan showed the bent LHV. On the diagnosis of outflow block of the left liver, a self-expandable metallic stent was placed in the LHV using an interventional approach, and the pressure in the LHV decreased from 27 cmH2O to 12 cmH2O. The bilirubin value decreased to 1.2 mg/dL on day 3. Outflow block of the LHV can happen after extended right hemihepatectomy with resection of the MHV. Early diagnosis and interventional stenting treatment can rescue the patient from congestive liver failure.

Additional hepatic artery embolization after liver venous deprivation for right hepatectomy: A case report.

Post hepatectomy Liver Failure (PHLF) is a fatal complication, especially after major liver resection. Insufficient remnant liver volume is a common cause of postoperative liver failure. Many strategies have been applied to induce the remnant liver hypertrophy: Portal vein embolization (PVE), PVE combined with hepatic vein embolization (LVD), two staged liver resection, Associated liver partition with portal vein ligation for staged hepatectomy (ALPPS). We present a case of a 39-year-old male patient who underwent LVD for preoperative liver hypertrophy. After LVD, the patient underwent additional artery embolization, and the patient's remaining liver volume increased by 63.2% in 7 weeks. The patient underwent a right hepatectomy and was discharged after 10 days, with no complications of postoperative liver failure. Simultaneous portal and hepatic vein embolization is a technique that has been applied recently because it can significantly promote the speed and extent of liver hypertrophy before major liver resection compared to portal vein embolization procedure alone. In this case, additional hepatic artery embolization may be an important factor lead to hypertrophy of the remnant liver, thereby shortening the waiting time for surgery and reducing the risk of tumor progression. Liver venous deprivation is safe and feasible to perform. Additional hepatic artery embolization may accelerate the hypertrophy of the remnant liver.

Fully automated assessment of the future liver remnant in a blood-free setting via CT before major hepatectomy via deep learning.

OBJECTIVES: To develop and validate a deep learning (DL) model for automated segmentation of hepatic and portal veins, and apply the model in blood-free future liver remnant (FLR) assessments via CT before major hepatectomy. METHODS: 3-dimensional 3D U-Net models were developed for the automatic segmentation of hepatic veins and portal veins on contrast-enhanced CT images. A total of 170 patients treated from January 2018 to March 2019 were included. 3D U-Net models were trained and tested under various liver conditions. The Dice similarity coefficient (DSC) and volumetric similarity (VS) were used to evaluate the segmentation accuracy. The use of quantitative volumetry for evaluating resection was compared between blood-filled and blood-free settings and between manual and automated segmentation. RESULTS: The DSC values in the test dataset for hepatic veins and portal veins were 0.66 ± 0.08 (95% CI: (0.65, 0.68)) and 0.67 ± 0.07 (95% CI: (0.66, 0.69)), the VS values were 0.80 ± 0.10 (95% CI: (0.79, 0.84)) and 0.74 ± 0.08 (95% CI: (0.73, 0.76)), respectively No significant differences in FLR, FLR% assessments, or the percentage of major hepatectomy patients were noted between the blood-filled and blood-free settings (p = 0.67, 0.59 and 0.99 for manual methods, p = 0.66, 0.99 and 0.99 for automated methods, respectively) according to the use of manual and automated segmentation methods. CONCLUSION: Fully automated segmentation of hepatic veins and portal veins and FLR assessment via blood-free CT before major hepatectomy are accurate and applicable in clinical cases involving the use of DL. CRITICAL RELEVANCE STATEMENT: Our fully automatic models could segment hepatic veins, portal veins, and future liver remnant in blood-free setting on CT images before major hepatectomy with reliable outcomes. KEY POINTS: Fully automatic segmentation of hepatic veins and portal veins was feasible in clinical practice. Fully automatic volumetry of future liver remnant (FLR)% in a blood-free setting was robust. No significant differences in FLR% assessments were noted between the blood-filled and blood-free settings.

Evaluation of ventral branches of segment VI portal vein relative to the right hepatic vein in laparoscopic right anterior sectionectomy.

INTRODUCTION: The right intersectional plane and the right hepatic hilum were noted too often exhibit anatomical variations, making difficult the laparoscopic right anterior sectionectomy (LRAS). METHODS: We analyzed the anatomical features employing 3D-CT images of 55 patients, and evaluated these features according to the course of ventral branches of segment VI of the portal vein (PV, P6a) relative to the right hepatic vein (RHV). RESULTS: P6a run on the dorsal side of RHV in 32 patients (58%, Dorsal-P6a) and the ventral side of RHV in 23 (42%, Ventral-P6a). Ventral-P6a had more patients with S6 partially drained by middle hepatic vein (MHV, 39% vs. 0%, P < 0001), the narrower angle between the anterior and posterior branches of PV (73.1° vs. 93.8°, P = 0.006), the wider angle between the RHV and inferior vena cava  (54.3° vs. 44.3°, P < 0.001), and more steeply pitched angle between S6 and S7 along the RHV (140.6° vs. 162.0°, P < 0.001) compared to Dorsal-P6a. CONCLUSION: In LRAS for Dorsal-P6a patients, the transection surface was relatively flat. In LRAS for Ventral-P6a patients, the narrow space between anterior and posterior glissons makes difficult the glissonean approach. The transection plane was steeply pitched, and RHV was partially exposed. S6 was often partially drained to MHV in 39% of the Ventral-P6a patients, which triggers congestion during liver transection of a right intersectional plane after first splitting the confluence of this branch.

CIRSE Standards of Practice on Portal Vein Embolization and Double Vein Embolization/Liver Venous Deprivation.

This CIRSE Standards of Practice document is aimed at interventional radiologists and provides best practices for performing liver regeneration therapies prior to major hepatectomies, including portal vein embolization, double vein embolization and liver venous deprivation. It has been developed by an expert writing group under the guidance of the CIRSE Standards of Practice Committee. It encompasses all clinical and technical details required to perform liver regeneration therapies, revising the indications, contra-indications, outcome measures assessed, technique and expected outcomes.

Head-to-Head Comparison of Hepatic Vein and Superior Vena Cava Flow Velocity Waveform Analyses for Predicting Elevated Right Atrial Pressure.

OBJECTIVE: Blood flow in the hepatic veins and superior vena cava (SVC) reflects right heart filling; however, their Doppler profiles are often not identical, and no studies have compared their diagnostic efficacies. We aimed to determine which venous Doppler profile is reliable for detecting elevated right atrial pressure (RAP). METHODS: In 193 patients with cardiovascular diseases who underwent cardiac catheterization within 2 d of echocardiography, the hepatic vein systolic filling fraction (HV-SFF) and the ratio of the peak systolic to diastolic forward velocities of the SVC (SVC-S/D) were measured. HV-SFF < 55% and SVC-S/D < 1.9 were regarded as elevated RAP. We also calculated the fibrosis 4 index (FIB-4) as a serum liver fibrosis marker. RESULTS: HV-SFF and SVC-S/D were feasible in 177 (92%) and 173 (90%) patients, respectively. In the 161 patients in whom both venous Doppler waveforms could be measured, HV-SFF and SVC-S/D were inversely correlated with RAP (r = -0.350, p < 0.001; r = -0.430, p < 0.001, respectively). SVC-S/D > 1.9 showed a significantly higher diagnostic accuracy of RAP elevation compared with HV-SFF < 55% (area under the curve, 0.842 vs. 0.614, p < 0.001). Multivariate analyses showed that both FIB-4 (ß = -0.211, p = 0.013) and mean RAP (ß = -0.319, p < 0.001) were independent determinants of HV-SFF. In contrast, not FIB-4 but mean RAP (ß = -0.471, p < 0.001) was an independent determinant of SVC-S/D. The diagnostic accuracy remained unchanged when HV-SFF < 55% was considered in conjunction with the estimated RAP based on the inferior vena cava morphology. Conversely, SVC-S/D showed an incremental diagnostic value over the estimated RAP. CONCLUSIONS: SVC-S/D enabled a more accurate diagnosis of RAP elevation than HV-SFF.

MRI Using Gadoxetic Acid in the Work-Up of Liver Nodules Not Conclusively Benign in Budd-Chiari Syndrome: A Prospective Long-Term Follow-Up.

Introduction: The incidence of hepatocellular carcinoma (HCC) in Budd-Chiari syndrome (BCS) is unknown and there is no validated diagnostic work-up to define the liver nodules with arterial phase hyperenhancement (APHE), suggesting malignancy. This prospective study evaluates HCC incidence in a Western cohort of patients with BCS and assesses the performance of MRI with hepatobiliary contrast (HB-MRI) for nodule characterization. Methods: Patients with BCS followed in our hospital were prospectively evaluated by MRI with extracellular contrast (EC-MRI). Nodules with APHE categorized as non-conclusively benign by 2 radiologists were studied by HB-MRI and reviewed by 2 radiologists blinded to the EC-MRI results. A new EC-MRI 1 year later and clinical, analytical, and sonographic follow-up every 6 months for a median of 10 years was performed. Results: A total of 55 non-conclusively benign nodules with APHE were detected at EC-MRI in 41 patients. While 32 of them were suggestive of HCC by EC-MRI, all the 55 nodules showed increased uptake of hepatobiliary contrast. An unequivocal central scar was seen in 12/55 nodules at HB-MRI regardless of it was not detected on the EC-MRI. None of the nodules was hypointense in the hepatobiliary phase (HBP). HCC was not detected during a median of 10 years of follow-up. Conclusions: Detection of nodules with APHE is frequent in patients with BCS, but HCC is rare in Western patients with BCS. While EC-MRI may detect nodules suggesting malignancy, the identification of contrast uptake in the HBP at HB-MRI may help categorize them as benign.

Caudo-dorsal approach combined with the occlusion of right hepatic vein and Pringle maneuver in laparoscopic anatomical resection of segment 7.

BACKGROUND: Laparoscopic anatomical resection of segment 7 (LARS7) remains a technically challenging procedure due to the deep anatomical location and the potential risk of injury to the right hepatic vein (RHV). Herein, we initiated an innovative technique of caudo-dorsal approach combined with the occlusion of the RHV and Pringle maneuver for LARS7 and presented the outcomes of our initial series. METHOD: Since January 2021, the patients who underwent LARS7 by using this novel technique were enrolled in this study. The critical aspect of this technique was the interruption of communication between the RHV and the inferior vena cava. Meanwhile, the Pringle maneuver was adopted to control the hepatic inflow. RESULT: A total of 11 patients underwent LARS7 by using this novel technique, which included 8 hepatocellular carcinoma, 2 bile duct adenocarcinoma and one focal nodular hyperplasia. The median operative time was 199 min (range of 151-318 min) and the median blood loss was 150 ml (range of 50-200 ml). The main trunk of the RHV was fully exposed on the cutting surface in all cases and no patient received perioperative blood transfusion. No procedure was converted to open surgery. Of note, no indications of CO2 gas embolism were observed in these cases after the introduction of double occlusion. Only one patient suffered from postoperative complications and healed after treatment. The median postoperative stay was 5 days (range of 4-7 days). The 90-day mortality was nil. At a median follow-up period of 19 months, all of the patients were alive without any evidence of tumor recurrence. CONCLUSION: The caudo-dorsal approach combined with the occlusion of RHV and the Pringle maneuver may be a feasible and expected technique for safe exposure of RHV in LARS7. Further validation of the feasibility and efficacy of this technique is needed.

Long term impact of transjugular intrahepatic portosystemic shunt (TIPS) creation on hepatic morphology.

PURPOSE: The purpose of this study was to evaluate long-term morphologic changes occurring in the liver after TIPS creation with correlation with hepatic function to gain insight on the physiologic impact of TIPS on the liver. METHODS: This retrospective study included patients who underwent TIPS creation between 2005 and 2022 and had contrasted CT or MRI studies prior to and between 1 and 2 years post procedure. Strict exclusion criteria were applied to avoid confounding. Parenchymal volume and vessel measurements were assessed on the pre- and post-TIPS CT or MRI and MELD scores calculated. RESULTS: Of 580 patients undergoing TIPS creation, 65 patients (mean age, 55 years; 36 males) had pre-TIPS and post-TIPS imaging meeting inclusion criteria at median 16.5 months. After TIPS, the mean MELD score increased (12.9 to 15.4; p = 0.008) and total liver volume decreased (1730 to 1432 mL; p < 0.001). However, the magnitude of volume change did not correlate with MELD change. Neither portosystemic gradient nor TIPS laterality correlated with total or lobar hepatic volume changes or MELD changes. The main portal vein diameter increased (15.0 to 18.7 mm; p < 0.001). Thrombosis of the hepatic vein used for TIPS creation resulted in a mean increase in MELD of +4.1 compared to -2.1 in patients who had a patent and normal hepatic vein (p = 0.007). CONCLUSIONS: Given lack of correlation between portosystemic gradient, hepatic atrophy, hepatic function, and TIPS laterality, the alterations in portal flow dynamics after TIPS may not be impactful to hepatic function. However, hepatic vein patency after TIPS correlated with improved hepatic function.

Transfemoral hepatic vein catheterization reduces procedure time in double vein embolization.

BACKGROUND: Double vein embolization with simultaneous embolization of the portal and hepatic vein aims to grow the future liver remnant in preparation for major hepatectomy. Transvenous hepatic vein embolization is usually done via a transjugular access. The purpose of this study is to describe the transfemoral approach as an alternative option and to discuss potential advantages. RESULTS: Twenty-three patients undergoing hepatic vein embolization via a transjugular (n = 10) or transfemoral access (n = 13) were evaluated retrospectively. In all cases the portal vein embolization was done first. All procedures were technically successful. There were no peri-interventional complications. Only two patients were not able to proceed to surgery. Standardized future liver remnant hypertrophy was non-inferior with the transfemoral approach compared to the transjugular route. Procedure time was significantly shorter in the transfemoral access group (40 ± 13 min) compared to the transjugular group (67 ± 13 min, p < 0.001). CONCLUSION: Transfemoral hepatic vein embolization is feasible, safe, and faster due to easier catheterization, improved stability, and simpler patient preparation. These findings will need to be validated in larger studies.

Resection and reconstruction of the largest abdominal vein system (the inferior vena cava, hepatic, and portal vein): a narrative review.

Background and Objective: As tumors invade major abdominal veins, surgical procedures are transformed from simple and basic to complicated and challenging. In this narrative review, we focus on what is currently known and not known regarding the technical aspects of major abdominal venous resection and its reconstruction, patency, and oncologic benefit in a cross-cutting perspective. Methods: A systematic literature search was performed in PubMed and Semantic Scholar from inception up to October 18, 2023. We reviewed 106 papers by title, abstract, and full text regarding resection or reconstruction of the inferior vena cava, hepatic vein confluence, portal vein (PV), and middle hepatic vein (MHV) tributaries in living donor liver transplantation (LDLT) in a cross-cutting perspective. Key Content and Findings: The oncologic benefit of aggressive hepatic vein resection with suitable reconstruction against adenocarcinoma remains unclear, and further studies are required to clarify this point. A superior mesenteric/PV resection is now a universal, indispensable, and effective procedure for pancreatic ductal adenocarcinoma. Although many case series using tailor-made autologous venous grafts have been reported, not only size mismatch but also additional surgical incisions and a longer operation time remain obstacles for venous reconstruction. The use of autologous alternative tissue remains only an alternative procedure because the patency rate of customized tubular conduit type to interpose or replace the resected vein is not known. Unlike arterial replacement, venous replacement using synthetic vascular grafts is still rarely reported and there are several inherent limitations except for reconstruction of tributaries of MHV in LDLT. Conclusions: Various approaches to abdominal vein resection and replacement or reconstruction are technically feasible with satisfactory results. Synthetic vascular grafts may be appropriate but have a certain rate of complications.

Dynamic changes of hepatic vein Doppler velocities predict preload responsiveness in mechanically ventilated critically ill patients.

BACKGROUND: Assessment of dynamic parameters to guide fluid administration is one of the mainstays of current resuscitation strategies. Each test has its own limitations, but passive leg raising (PLR) has emerged as one of the most versatile preload responsiveness tests. However, it requires real-time cardiac output (CO) measurement either through advanced monitoring devices, which are not routinely available, or echocardiography, which is not always feasible. Analysis of the hepatic vein Doppler waveform change, a simpler ultrasound-based assessment, during a dynamic test such as PLR could be useful in predicting preload responsiveness. The objective of this study was to assess the diagnostic accuracy of hepatic vein Doppler S and D-wave velocities during PLR as a predictor of preload responsiveness. METHODS: Prospective observational study conducted in two medical-surgical ICUs in Chile. Patients in circulatory failure and connected to controlled mechanical ventilation were included from August to December 2023. A baseline ultrasound assessment of cardiac function was performed. Then, simultaneously, ultrasound measurements of hepatic vein Doppler S and D waves and cardiac output by continuous pulse contour analysis device were performed during a PLR maneuver. RESULTS: Thirty-seven patients were analyzed. 63% of the patients were preload responsive defined by a 10% increase in CO after passive leg raising. A 20% increase in the maximum S wave velocity after PLR showed the best diagnostic accuracy with a sensitivity of 69.6% (49.1-84.4) and specificity of 92.8 (68.5-99.6) to detect preload responsiveness, with an area under curve of receiving operator characteristic (AUC-ROC) of 0.82 ± 0.07 (p = 0.001 vs. AUC-ROC of 0.5). D-wave velocities showed worse diagnostic accuracy. CONCLUSIONS: Hepatic vein Doppler assessment emerges as a novel complementary technique with adequate predictive capacity to identify preload responsiveness in patients in mechanical ventilation and circulatory failure. This technique could become valuable in scenarios of basic hemodynamic monitoring and when echocardiography is not feasible. Future studies should confirm these results.

Assessment of drainage vein of focal nodular hyperplasia using contrast-enhanced ultrasound.

PURPOSE: Identification of drainage vessels is useful for differential diagnosis of hepatic tumors. Direct drainage to the hepatic vein has been reported to occur in focal nodular hyperplasia (FNH), but studies evaluating the drainage veins of FNH are limited. We aimed to investigate the detection rate of the FNH drainage vein and the factors related to visualization of the drainage vein on contrast-enhanced ultrasound (CEUS). METHODS: Fifty consecutive patients with 50 FNH lesions were retrospectively evaluated in this study. We calculated and compared the detection rate of the FNH drainage vein on CEUS, contrast-enhanced magnetic resonance imaging (CEMRI), and contrast-enhanced computed tomography (CECT), and identified the factors correlated with visualization of the FNH drainage vein on CEUS by using multivariate logistic regression analyses. RESULTS: Visualization of the drainage vein was confirmed in 31 of 50 lesions (62%) using CEUS, three of 44 lesions (6.8%) using CEMRI, and one of 18 lesions (5.6%) using CECT. The detection rate of the FNH drainage vein on CEUS was significantly higher than that on CEMRI and CECT (p < 0.001). Multivariate analysis identified lesion size (≥ 25 mm) and detection of the spoke-wheel pattern on Doppler US as independent factors for drainage vein detection in FNH. CONCLUSION: Our study showed that rapid FNH drainage to the hepatic vein was observed at a relatively high rate on CEUS, suggesting that CEUS focusing on detection of drainage veins is important for diagnosing FNH.

Histological and radiological analysis of simultaneous dual hepatic vein embolization for right-sided major hepatectomy.

PURPOSE: Simultaneous dual hepatic vein embolization (DHVE) has been proposed for safe right-sided hepatectomy, with good results for liver hypertrophy and function. However, the histological and radiological findings of DHVE have not been thoroughly investigated. METHODS: This study included 14 patients who underwent DHVE before right-sided major hepatectomy. DHVE was performed if the future liver remnant was < 35% or borderline, but with concomitant vascular resection. The liver function was assessed using the signal intensity on Gd-EOB-DTPA-MRI. A histological evaluation of the area of DHVE and portal vein embolization (PVE) were performed. RESULTS: The median pre- and post-functional liver remnants were 363 ml and 498 ml, respectively (p < 0.001). The median growth rate was 48.6%, and there was no post-hepatectomy liver failure in the patients who underwent DHVE. The signal intensity ratio in the area of DHVE was lower than that in the areas of PVE and the remnant liver (p < 0.01). The degree of congestion and necrosis was greater in the area of DHVE than in the area of PVE alone (p < 0.01 and p = 0.04, respectively). CONCLUSIONS: We observed good liver hypertrophy after DHVE and histological and radiological changes in the area of DHVE. Our findings provide a compelling rationale for further investigation of the mechanism of liver hypertrophy in DHVE.

Double hepatic vein reconstruction during extended anatomical resection of segment 8 for colorectal liver metastasis.

BACKGROUND: Hepatic vein reconstruction (HVR) is occasionally necessary for resecting hepatic malignancies to ensure surgical margins while preserving remnant liver function [1]. Reports of multiple HVR are rare due to the highly technical demanding procedure and high risk of morbidity [2]. We introduce our procedure of double HVR for metastatic liver tumors invading the right hepatic vein (RHV) and middle hepatic vein (MHV). METHODS: The patient was a 66-year-old man with colorectal liver metastasis in segment 8, invading RHV and MHV. Due to impaired liver function, extended right hemihepatectomy was unsuitable. Thus, extended anatomical resection of segment 8 with double HVR was performed. The liver was completely mobilized and the RHV and MHV were secured. After liver parenchyma dissection, the specimen was connected by RHV and MHV (Fig. 1). The MHV was dissected and reconstructed using a right superficial femoral vein graft while the RHV remained connected [3]. Reconstruction of the MHV was performed on the posterior wall of the proximal side, followed by the anterior wall, using 4-point supporting threads. Anastomosis was performed by the over-and-over suture method. On the distal side, two-point supporting threads were applied. After specimen removal, the RHV was resected and reconstructed in the same manner using a left internal jugular vein graft [4]. RESULTS: The patient was discharged on postoperative day 14 with no signs of liver failure. Computed tomography performed six months after surgery revealed no graft occlusion (Fig. 2). CONCLUSION: In appropriately selected patients, this technique may be a useful option for preserving the remnant liver function.

An unexpected location of pleural catheter in a hepatic vein: A case report.

Pleural catheters are widely used for patients with pleural effusions. Several complications with limited morbidity have been reported. We report, to our knowledge, the first case of a pleural catheter insertion into the hepatic vein, passed through the inferior vena cava, and the tip reaching the right atrium, which may be reduced using additional imaging during thoracocentesis.

Impact of the inferior vena cava morphology on fluid dynamics of the hepatic veins.

We reported previously that a large vertical interval between the hepatic segment of the inferior vena cava (IVC) and right atrium (RA), referred to as the IVC-RA gap, was associated with more intraoperative bleeding during hemi-hepatectomy. We conducted a computational fluid dynamics (CFD) study to clarify the impact of fluid dynamics resulting from morphologic variations around the liver. The subjects were 10 patients/donors with a large IVC-RA gap and 10 patients/donors with a small IVC-RA gap. Three-dimensional reconstructions of the IVC and hepatic vessels were created from CT images for the CFD study. Median pressure in the middle hepatic vein was significantly higher in the large-gap group than in the small-gap group (P = 0.008). Differences in hepatic vein pressure caused by morphologic variation in the IVC might be one of the mechanisms of intraoperative bleeding from the hepatic veins.

Quantitative anatomy of the large variant right hepatic vein: A systematic three-dimensional analysis.

Anatomical variations of the right hepatic vein, especially large variant right hepatic veins (≥5 mm), have important clinical implications in liver transplantation and resection. This study aimed to evaluate anatomical variations of the right hepatic vein using quantitative three-dimensional visualization analysis. Computed tomography images of 650 patients were retrospectively analyzed, and three-dimensional visualization was applied using the derived data to analyze large variant right hepatic veins. The proportion of the large variant right hepatic vein was 16.92% (110/650). According to the location and number of the variant right hepatic veins, the configuration of the right hepatic venous system was divided into seven subtypes. The length of the retrohepatic inferior vena cava had a positive correlation with the diameter of the right hepatic vein (rs = 0.266, p = 0.001) and the variant right hepatic veins (rs = 0.211, p = 0.027). The diameter of the right hepatic vein was positively correlated with that of the middle hepatic vein (rs = 0.361, p < 0.001), while it was inversely correlated with that of the variant right hepatic veins (rs = -0.267, p = 0.005). The right hepatic vein diameter was positively correlated with the drainage volume (rs = 0.489, p < 0.001), while the correlation with the variant right hepatic veins drainage volume was negative (rs = -0.460, p < 0.001). The number of the variant right hepatic veins and their relative diameters were positively correlated (p < 0.001). The volume and percentage of the drainage area of the right hepatic vein decreased significantly as the number of the variant right hepatic vein increased (p < 0.001). The findings of this study concerning the variations of the hepatic venous system may be useful for the surgical planning of liver resection or transplantation.