Surgical techniques used in adult living donor liver transplantation

Ultrasound innovations in abdominal radiology: multiparametic imaging in liver transplantation

PURPOSE

Ultrasound plays a central role in liver transplant evaluation. Acute, subacute, and chronic complications can be readily identified using grayscale and color Doppler ultrasound. Contrast-enhanced ultrasound adds a new dimension to liver transplant evaluation, depicting vascular and parenchymal processes with exquisite detail. In addition, emerging evidence suggests that contrast-enhanced ultrasound may allow for localization of biliary leak in select patients. We aimed to assess the use of multiparametric ultrasound-including grayscale, color and spectral Doppler, and contrast-enhanced ultrasound-in the setting of liver transplantation.

METHODS

A literature review was performed using the MEDLINE bibliographic database through the National Library of Medicine. The following terms were searched and relevant citations assessed: "abdominal ultrasound," "contrast-enhanced ultrasound," "liver transplant," and "ultrasound."

RESULTS

Grayscale and color Doppler ultrasound represent the mainstay imaging modalities for postoperative liver transplant evaluation. The addition of contrast enhancement plays a complementary role and can provide valuable information related to the allograft vasculature, parenchyma, and biliary tree. The appropriate implementation of grayscale, color Doppler, and contrast-enhanced ultrasound can optimize sensitivity, specificity, and accuracy for the detection of liver transplantation complications, including hepatic artery stenosis, biliary leakage, and infection.

CONCLUSION

Multimodal sonographic evaluation is essential to identify postoperative complications in liver transplant recipients. Contrast-enhanced ultrasound may be of value in challenging cases, providing excellent anatomic delineation and reducing the risk of false-positive and false-negative diagnoses. A broad familiarity with appropriate applications of both nonenhanced and contrast-enhanced ultrasound may help radiologists optimize allograft assessment and improve patient outcomes.

Multimodality Imaging after Liver Transplant: Top 10 Important Complications

Patients who have undergone liver transplant are now regularly seen in day-to-day radiology practice. All surgical techniques for liver transplant require arterial, portal venous, hepatic venous and caval, and biliary anastomoses. This review is focused on the 10 "not to be missed" complications of liver transplant that affect the health and life of the graft and graft recipient. Arterial complications are the most common and devastating. Early hepatic artery thrombosis may be catastrophic because the biliary tree is solely dependent on the hepatic artery after transplant and collateral vessels have not yet formed. In contrast, delayed hepatic artery thrombosis may be more insidious as collateral arteries develop. US findings of delayed hepatic artery thrombosis may be similar to those of hepatic artery stenosis and celiac artery stenosis. Splenic artery steal syndrome is an increasingly recognized cause of graft ischemia. Venous complications are much less common. Hepatic venous and caval complications are notable for their increased incidence in living-donor and pediatric transplants. Biliary complications often result from arterial ischemia. Biliary cast syndrome is a notable example in which ischemic biliary mucosa sloughs into and obstructs the duct lumens. Neoplasms also may occur within the hepatic graft and may be due to recurrent malignancy, posttransplant lymphoproliferative disorder, or metastases. US is the initial imaging modality of choice, particularly in the acute postoperative setting. Further evaluation with contrast-enhanced US, CT, or MRI; catheter angiography; endoscopic retrograde cholangiopancreatography; and/or nuclear medicine studies is performed as needed. An invited commentary by Bhargava is available online. Online supplemental material is available for this article. ^©RSNA, 2022.

Magnetic Resonance Imaging of Liver Transplant

MR imaging increasingly has been adopted for follow-up imaging post-liver transplantation and for diagnosis of its complications. These include vascular and biliary complications as well as post-transplant malignancies. Interpretation of postoperative MR imaging should take into account the surgical technique and expected post-transplant changes. Contrast-enhanced MR imaging has high sensitivity for identification of vascular complications. MR cholangiopancreatography on the other hand is the most accurate noninvasive method for evaluation of biliary complications.

Biliary complications after liver transplantation: A review

After liver transplantation, the prevalence of complications related to the biliary system is 6-35%. In recent years, the diagnosis and treatment of biliary problems has changed markedly. The two standard methods of biliary reconstruction in liver transplant recipients are the duct-to-duct choledochocholedochostomy and the Roux-en-Y-hepaticojejunostomy. Biliary leakage occurs in approximately 5-7% of transplant cases. Leakage from the site of anastomosis, the T-tube exit site and donor or recipient remnant cystic duct is well described. Symptomatic bile leakage should be treated by stenting of the duct by endoscopic retrograde cholangiopancreatography (ERCP) or percutaneous transhepatic cholangiography (PTCD). Biliary strictures can occur at the site of the anastomosis (anastomotic stricture; AS) or at other locations in the biliary tree (non-anastomotic strictures; NAS). AS occur in 5-10% of cases and are due to fibrotic healing. Treatment by ERCP or PTCD with dilatation and progressive stenting is successful in the majority of cases. NAS can occur in the context of a hepatic artery thrombosis, or with an open hepatic artery (ischaemic type biliary lesions or ITBL). The incidence is 5-10%. NAS has been associated with various types of injury, e.g. macrovascular, microvascular, immunological and cytotoxic injury by bile salts. Treatment can be attempted with multiple sessions of dilatation and stenting of stenotic areas by ERCP or PTCD. In cases of localized diseased and good graft function, biliary reconstructive surgery is useful. However, a significant number of patients will need a re-transplant. When biliary strictures or ischaemia of the graft are present, stones, casts and sludge can develop.

Live donors in liver transplantation

Living donor liver transplantation (LDLT) has been controversial since its inception. Begun in response to deceased donor organ shortage and waiting list mortality, LDLT was initiated in 1989 in children, grew rapidly after its first general application in adults in the United States in 1998, and has declined since 2001. There are significant risks to the living donor, including the risk of death and substantial morbidity, and 2 highly publicized donor deaths are thought to have contributed to decreased enthusiasm for LDLT. Significant improvements in outcomes have been seen over recent years, and data, including from the National Institutes of Health-funded Adult-to-Adult Living Donor Liver Transplantation Cohort Study (A2ALL), have established a survival benefit from pursuing LDLT. Despite this, LDLT still composes less than 5% of adult liver transplants, significantly less than in kidney transplantation where living donors compose approximately 40% of all transplantations performed. The ethics, optimal utility, and application of LDLT remain to be defined. In addition, most studies to date have focused on posttransplantation outcomes and have not included the effect of the learning curve on outcome or the potential impact of LDLT on waiting list mortality. Further growth of LDLT will depend on defining the optimal recipient and donor characteristics for this procedure as well as broader acceptance and experience in the public and in transplant centers.

Adult live donor liver transplantation

The increasing awareness of liver diseases and their early detection have led to an increase in the number of transplant waiting list candidates over the past decade. This need has not been matched by the actual number of orthotopic liver transplantations performed. Live donor liver transplantation (LDLT) is an innovative surgical technique intended to expand the available organ donor pool. Although LDLT offers definite advantages to the recipient, it offers none to the donor except for the possibility of psychological well-being. Clinical research studies aimed at the prospective collection of data for donors and recipients need to be conducted.

Adult-to-Adult Living Donor Liver Transplantation: History, Current Practice, and Implications for the Future

More than 1600 Americans have received adult-to-adult living donor liver transplants. As the number of patients with end-stage liver disease is expected to grow significantly in the next 20 years due to hepatitis C infection, living donor liver transplantation has become a promising solution to the shortage of donor organs. The use of living donors provides organs in an environment of scarcity, allows patients to receive transplants when medically optimized, and produces liver segments with minimal ischemic damage. The donor complications most frequently cited in the medical literature include bile leaks and strictures, biloma, hepatic encephalopathy, wound infection, and pressure sores. In the wake of 2 donor deaths in the United States and subsequent media publicity, there have been new efforts by the transplant community to describe the risks and outcomes for donors, and establish safeguards to protect them from excessive pressure to donate.

Living donor surgery: overview of surgical and anesthesia issues

Organ transplantation occupies the center stage in the treatment of many forms of end-stage organ disease. When the limits of conventional medical care are exhausted, bridging therapies, cadaveric transplantation, and posttransplant medical care come to the fore. Living donor transplantation has grown out of the numerical and immunosuppression limitations of this process. Living donor transplantation medicine and surgery encompass two of the most fascinating and compelling social and ethical dilemmas of modern health care. This article provides an overview of medical and ethical concerns for those who decide to become living donors and those who care for them in the perioperative period.

Adult living donor liver transplantation

Adult living donor liver transplantation (LDLT) begun in response to deceased donor organ shortage and waiting list mortality, grew rapidly after its first general application in the United States in 1998. There are significant risks to the living donor, including the risk of death and substantial morbidity, and two highly publicized donor deaths have led to decreased LDLT since 2001. Significant improvements in outcomes have been seen over recent years that have not been reported in single center studies; however, LDLT still comprises less than 5% of adult liver transplants, significantly less than in kidney transplantation where living donors now comprise the majority. The ethics, optimal utility and application of LDLT remain to be defined. In addition, studies to date have focused on post-transplant outcomes and not included the potential impact of LDLT on waiting time mortality. Future analyses should include appropriate control or comparison groups that capture the effect of LDLT on overall mortality from the time of listing. Further growth of LDLT will depend on defining the optimal recipient and donor characteristics for this procedure as well as broader acceptance and experience in the public and in transplant centers.