Is Routine Intraoperative Contrast-Enhanced Ultrasonography Useful During Whole Liver Transplantation?

Intraoperative indocyanine green fluorescence imaging to predict early hepatic arterial complications after liver transplantation

The purpose of this study was to propose an innovative intraoperative criterion in a liver transplantation setting that would judge arterial flow abnormality that may lead to early hepatic arterial occlusion, that is, thrombosis or stenosis, when left untreated and to carry out reanastomosis. After liver graft implantation, and after ensuring that there is no abnormality on the Doppler ultrasound (qualitative and quantitative assessment), we intraoperatively injected indocyanine green dye (0.01 mg/Kg), and we quantified the fluorescence signal at the graft pedicle using ImageJ software. From the obtained images of 89 adult patients transplanted in our center between September 2017 and April 2019, we constructed fluorescence intensity curves of the hepatic arterial signal and examined their relationship with the occurrence of early hepatic arterial occlusion (thrombosis or stenosis). Early hepatic arterial occlusion occurred in 7 patients (7.8%), including 3 thrombosis and 4 stenosis. Among various parameters of the flow intensity curve analyzed, the ratio of peak to plateau fluorescence intensity and the jagged wave pattern at the plateau phase were closely associated with this dreaded event. By combining the ratio of peak to plateau at 0.275 and a jagged wave, we best predicted the occurrence of early hepatic arterial occlusion and thrombosis, with sensitivity/specificity of 0.86/0.98 and 1.00/0.94, respectively. Through a simple composite parameter, the indocyanine green fluorescence imaging system is an additional and promising intraoperative modality for identifying recipients of transplant at high risk of developing early hepatic arterial occlusion. This tool could assist the surgeon in the decision to redo the anastomosis despite normal Doppler ultrasonography.

Feasible management of median arcuate ligament syndrome in orthotopic liver transplantation recipients

BACKGROUND

In orthotopic liver transplantation (OLT) recipients, median arcuate ligament syndrome (MALS) is considered a risk factor for hepatic arterial thrombosis (HAT), which is dreadful for OLT recipients. Different alternative surgical procedures have been proposed to overcome the impact of MALS on transplantation, but clinical evidence is still scarce.

AIM

To evaluate the feasible surgical management of MALS to reduce complications in OLT patients.

METHODS

Data for 288 consecutive patients who underwent OLT at The First Hospital of Jilin University between January 2017 and July 2020 were retrospectively reviewed. The surgical management of median arcuate ligament (MAL) and modifications to the arterial anastomosis were recorded. The perioperative and long-term prognosis of MALS recipients were noted. Detailed preoperative and postoperative data of patients were analyzed in a descriptive manner.

RESULTS

Eight patients with MALS were included in this study. The first patient with MALS received no intervention during the primary surgery and developed postoperative HAT. Salvage liver transplantation with MAL division was successfully performed. Gastroduodenal artery (GDA) preservation with splenic artery ligation was performed on three patients, only GDA preservation was performed on two patients, and no intervention was performed on two patients. No patient developed HAT after surgery and postoperative recovery was satisfactory.

CONCLUSION

The preservation of collateral circulation between the superior mesenteric artery and celiac trunk via the GDA with or without splenic artery ligation is a safe and feasible alternative to MAL division.

Contemporary Management of Median Arcuate Ligament in Liver Transplantation

Median arcuate ligament (MAL) can impair arterial inflow during orthotopic liver transplantation (OLT). Furthermore, approaches to ensure optimal vascular inflow in the presence of MAL is not standardized.

Methods

We undertook a systematic review according to the Cochrane systematic review protocol and Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We analyzed the incidence of MAL, investigations, treatment options, and potential complications associated with MAL intervention in patients undergoing OLT. After the exclusion criteria were implemented, the dataset from the final 21 manuscripts yielded 117 patients who underwent a liver transplant in the presence of MAL.

Results

The incidence of MAL in patients undergoing OLT is between 1.6% and 12%. In 63.2% of cases, an open approach for MAL intervention was undertaken. Hepatic artery thrombosis developed in 17% (7) patients without MAL intervention versus 2.6% (2) after MAL intervention. Seven grafts (5.9%) were lost after OLT in patients with MAL. Three (3.9%) patients developed arterial stenosis post-MAL intervention.

Conclusions

We propose an algorithm for intraoperative assessment and management of liver transplant arterial inflow in the presence of MAL based on the hepatic artery flow changes with respiration, following clamping of the recipient gastroduodenal artery. In the presence of a 30%-50% flow variation on respiration, the arterial inflow should be established preserving additional inflow from the recipient gastroduodenal artery. Consider an open MAL release if the flow remains insufficient. A poor arterial flow with no variation with respiration and lack of evidence of aortoiliac atherosclerosis indicates the need for arterial jump graft.

Non-invasive diagnosis and follow-up in liver transplantation

The field of liver transplantation directly or indirectly embodies all liver diseases, in addition to specific ones related to organ rejection (cellular and humoral). The recommended non-invasive methods for determining the indication for liver transplantation are the Model for End-stage Liver Disease score, and the alpha-foetoprotein score in case of hepatocellular carcinoma. Radiological methods are the cornerstones for the diagnosis of vascular and biliary complications after liver transplantation. The possible diseases of the liver graft after transplantation are multiple and often intertwined. Non-invasive diagnostic methods have been poorly evaluated in this context, apart from the recurrence of hepatitis C. Liver biopsy remains the gold standard for evaluating graft lesions in the majority of cases, especially graft rejection.

Advanced ultrasound applications in the assessment of renal transplants: contrast-enhanced ultrasound, elastography, and B-flow

Ultrasound is routinely used as the first imaging exam for evaluation of renal transplants and can identify most major surgical complications and evaluate vascularity with color Doppler. Ultrasound is limited, however, in the detection of parenchymal disease processes and Doppler evaluation is also prone to technical errors. Multiple new ultrasound applications have been developed and are under ongoing investigation which could add additional diagnostic capability to the routine ultrasound exam with minimal additional time, cost, and patient risk. Contrast-enhanced ultrasound (CEUS) can be used off-label in the transplant kidney, and can assist in detection of infection, trauma, and vascular complications. CEUS also can demonstrate perfusion of the transplant assessed quantitatively with generation of time-intensity curves. Future directions of CEUS include monitoring treatment response and microbubble targeted medication delivery. Elastography is an ultrasound application that can detect changes in tissue elasticity, which is useful to diagnose diffuse parenchymal disease, such as fibrosis, otherwise unrecognizable with ultrasound. Elastography has been successfully applied in other organs including the liver, thyroid, and breast; however, it is still under development for use in the transplant kidney. Unique properties of the transplant kidney including its heterogeneity, anatomic location, and other technical factors present challenges in the development of reference standard measurements. Lastly, B-flow imaging is a flow application derived from B-mode. This application can show the true lumen size of a vessel which is useful to depict vascular anatomy and bypasses some of the pitfalls of color Doppler such as demonstration of slow flow.