Search In this Thesis
   Search In this Thesis  
العنوان
Multiple hepatic veins reconstruction in right lobe grafts in living donor liver transplantation ... Accept or reject? \
المؤلف
Sadary, Abanoub Samir Nazim.
هيئة الاعداد
باحث / أبانوب سمير نظيم سداري
مشرف / محمود أحمد شوقي المتيني
مشرف / محمد محمد بهاء الدين احمد
مشرف / كمال ممدوح كمال السيد
تاريخ النشر
2018.
عدد الصفحات
147 p. :
اللغة
الإنجليزية
الدرجة
ماجستير
التخصص
جراحة
تاريخ الإجازة
1/1/2018
مكان الإجازة
جامعة عين شمس - كلية الطب - الجراحة العامة
الفهرس
Only 14 pages are availabe for public view

from 147

from 147

Abstract

Chronic liver disease and cirrhosis are important causes of morbidity and mortality in the world. Moreover, the burden of chronic liver disease is projected to increase due in part to the increasing prevalence of end-stage liver disease and HCC secondary to NAFLD and HCV.
According to the latest US Centers for Disease Control and Prevention sources, cirrhosis remains the 12th leading cause of death for adults in the United States, with 27,013 deaths reported in 2004 and a death rate of nearly 9.2 cases per 100,000 persons. This accounts for 1.1% of total deaths. Unfortunately, this number may grossly underestimate the real impact of ESLD because it does not include acute liver failure or other etiologies that may lead to the need for LT.
In adults, the most frequent causes of liver disease that leads to a need for a liver transplant is chronic infection with hepatitis C virus. Other conditions in adults that commonly necessitate a liver transplant include: hepatitis B virus, Non Alcoholic Fatty Liver Disease, Primary Biliary Cirrhosis, Primary Sclerosing Cholangitis, and hepatocelllular carcinoma.
Liver transplantation is the best treatment option for end-stage liver disease, including early HCC associated with advanced cirrhosis. However, the application of liver transplantation is severely limited by the shortage of deceased donor grafts; hence many patients die from progression of the disease while waiting for a graft.
The shortage of cadaveric livers has sparked an interest in living donor liver transplantation (LDLT). LDLT may increase the liver graft pool and reduce waiting list mortality.
In adults, right hemiliver graft can satisfy the demands of the recipient’s metabolism and prevent small-for-size syndrome.
In Asian countries, close to 90% of liver transplantations are from living donors because of social and religious factors. In western countries and especially in the UNOS area, some recent donor deaths led to a decline in LDLT numbers. The advantage of LDLT is the use of an optimal healthy donor, minimal ischemic time, elective surgery, and timing of transplantation owing to the recipient’s need and medical stability. A further advantage of LDLT is the possibility of ABO-incompatible transplantation.
Despite great technological and immunological advances in the field of LT, there are still significant complications of recipients. These complications include biliary, vascular, neurological, SFSS, early rejection, pneumonia, gastrointestinal hemorrhage, renal insufficiency or failure, bowel obstruction, post-operative collections, infection and malignant recurrence. The previous complications have a significant impact on the morbidity and mortality of recipients.
Right lobe living donor liver transplantation (LDLT) was adapted and later became the most successful and safe source for liver allografts as the deceased organ donation remains scarce.
The living donor liver allograft is a partial graft and graft size discrepancy always remains a concern. Graft-to-recipient-weight ratio >0.8% is considered an adequate for proper liver graft functioning after the transplantation. To alleviate the problem of graft size disparity, an extended right liver graft, which includes the trunk of the middle hepatic vein (MHV), was devised and later same group concluded the safety of the MHV inclusion without any morbidity in the donors.
However, inclusion of the MHV in the donor liver graft remains a topic of controversy as the critics think this may increase chance of donor morbidity and right liver allografts without the MHV yield similar results. But, the grafts that are devoid of MHV may cause worrisome congestion of anterior sector (segment 5 and segment 8) that may increase the risk of post-operative liver dysfunction and infection. All the MHV tributaries must be reconstructed during backtable procedure to provide an effective venous drainage, because a balanced portal vein and hepatic artery inflow along with an adequate venous outflow are the crucial factors for successful outcomes after LDLT.
In absence of an adequate graft venous drainage, the portal inflow can cause damaging effects on the liver allograft and delay the regenerative capacity that may cause liver dysfunction in post-operative period leading to small-for-size syndrome. The right liver graft with reconstructed anterior sector venous drainage provides a functioning liver mass comparable to an extended right liver graft.
Many technical breakthroughs, modifications in donor hepatic transection and backtable innovative venoplasty procedures that evolved over the last decade have led to a successful long-term outcome after transplantation in most of the LDLT centers. Thus, the venoplasty of MHV tributaries (if MHV not included in graft) has been adapted as the standard procedure in liver transplantation. The venoplasty can be accomplished by using cryopreserved vascular grafts or synthetic polytetrafluoroethylene (PTFE) grafts.
Concerns about donor remnant liver congestion precluded the surgeons from including the MHV in the graft, many transplant centres started using right liver grafts without inclusion of the MHV or modified techniques such as inclusion of the MHV till the V4b drainage to prevent the donor remnant liver congestion. But, the liver grafts without the MHV often had congested anterior sector after liver graft implantation.
Studies showed increased risk of septic complications and graft dysfunction in right liver grafts with congested anterior sector. Hence, restoration of the graft venous drainage by a backtable venoplasty became a routine standard.
Initial arguments against the venoplasty were the size and the number of venous tributaries that require reconstruction. Venous branches >4mm diameter should be reconstructed. The backtable procedure is also influenced by presence of graft venous variations that are found to be present in approximately 40% of donor livers and presence of a single or multiple IRHVs draining to inferior vena cava (IVC) is a common type of short hepatic vein in right liver.
To prevent RHV anastomotic stenosis, various methods of enlarging the RHV orifice have been introduced. This can be carried out by simple enlargement of the orifice of the recipient vein by the creation of an anterior slit, down to its junction with the inferior vena cava (IVC), because the caliber of the recipient’s RHV or caval orifice should be larger than the caliber of the liver graft’s RHV for a wide and long-patent anastomosis.
Thus we can say, outflow tract reconstruction is critical for proper graft functioning in LDLT as any venous impedance can cause graft congestion that may lead to graft dysfunction and even early graft failure, especially in marginally-sized donor grafts, as venous outflow disturbance adversely affects the regenerative capacity of a partial liver graft. Hence, significantly large venous tributaries must be reconstructed by a backtable venoplasty using vascular grafts.