زراعة الكبد

Liver transplantation
تدخل
Human liver
ICD-9-CM 50.5
MeSH D016031


زرع الكبد 'أو 'زرع الكبد 'هو استبدال كبد مريض مع كبد صحي allograft. ,الأسلوب الأكثر شيوعا هو زرع orthotopic ، والتي تتم بإزالة الكبد الأصلي والاستعاضة عنها بالكبد الممنوح في نفس الموقع التشريحي للكبد الأصلي. زرع الكبد في الوقت الحاضر هو الخيار المقبول لعلاج أمراض الكبد حيث يشكل نهاية مرحلة الفشل الكبدي الحاد. كما أنها واحدة من أغلى العلاجات في الطب الحديث.


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التاريخ

أول زاعة لكبدبشرى قد أجريت في عام 1963 وأجراها فريق جراحى يقوده د. توماس ستارز1[1] من دنفر كولورادو ، بالولايات المتحدة. اجرى الدكتور Starzl عدة عمليات زرع إضافية على مدى السنوات القليلة التى تلت قبل أن تحقق أول نجاح على المدى القصير في عام 1967 مع بقاء المريض سنة واحدة الأولى بعد الزرع تحت المراقبة. وعلى الرغم من تطور تقنيات الجراحة ، فلا تزال زراعة الكبد تجريبية خلال حقبة السبعينات، مع بقاء المريض مدة سنة واحدة على مقربة من 25 ٪.[2] ومع إدخال سيكلوسبورين ciclosporin من قبل السير روي كلان تحسنت بشكل ملحوظ نتائج المرضى ، وخلال الثمانيانات تم الاعتراف بأن زراعة الكبد هى العلاج السريري القياسي لكل من البالغين والاطفال المصابين الذين تشير الأدلة المناسبة بحاجتهم للزرع. ويتم إجراء عمليات زراعة الكبد الآن في أكثر من 100 مركزا في الولايات المتحدة الأمريكية ، وكذلك العديد من المراكز في أوروبا وأماكن أخرى. وكان معدل بقاء المرضى على قيد الحياة يتراوح بين 80-85 ٪ في السنة ، و تمت مواصلة تحسن النتائج ، على الرغم من أن عمليات زرع الكلى لا تزال تعد عملية عظمى مع مضاعفات متكررة. وللأسف ، فإن الكم المعروض من الكبد للزرع. allograft من مانحين غير أحياء هو قليل جدا ومتقلص بالنسبة لعدد المستفيدين المحتملين ، وأصبح واقعا وهو قد حفز التنمية مانحوا الكبد الأحياء.


Indications

Liver transplantation is potentially applicable to any acute or chronic condition resulting in irreversible liver dysfunction, provided that the recipient does not have other conditions that will preclude a successful transplant. Metastatic cancer outside liver, active drug or alcohol abuse and active septic infections are absolute contraindications. While infection with HIV was once considered an absolute contraindication, this has been changing recently. Advanced age and serious heart, pulmonary or other disease may also prevent transplantation (relative contraindications). Most liver transplants are performed for chronic liver diseases that lead to irreversible scarring of the liver, or cirrhosis of the liver. Another cause is cryptogenic liver disease. Some centers use the Milan criteria to select patients for liver transplantation.

Techniques

Before transplantation liver support therapy might be indicated (bridging-to-transplantation). Artificial liver support like liver dialysis or bioartificial liver support concepts are currently under preclinical and clinical evaluation. Virtually all liver transplants are done in an orthotopic fashion, that is the native liver is removed and the new liver is placed in the same anatomic location. The transplant operation can be conceptualized as consisting of the hepatectomy (liver removal) phase, the anhepatic (no liver) phase, and the postimplantation phase. The operation is done through a large incision in the upper abdomen. The hepatectomy involves division of all ligamentous attachments to the liver, as well as the common bile duct, hepatic artery, hepatic vein and portal vein. Usually, the retrohepatic portion of the inferior vena cava is removed along with the liver, although an alternative technique preserves the recipient's vena cava ("piggyback" technique).

The donor's blood in the liver will be replaced by an ice-cold organ storage solution, such as UW (Viaspan) or HTK until the allograft liver is implanted. Implantation involves anastomoses (connections) of the inferior vena cava, portal vein, and hepatic artery. After blood flow is restored to the new liver, the biliary (bile duct) anastomosis is constructed, either to the recipient's own bile duct or to the small intestine. The surgery usually takes between five and six hours, but may be longer or shorter due to the difficulty of the operation and the experience of the surgeon.

The large majority of liver transplants use the entire liver from a non-living donor for the transplant, particularly for adult recipients. A major advance in pediatric liver transplantation was the development of reduced size liver transplantation, in which a portion of an adult liver is used for an infant or small child. Further developments in this area included split liver transplantation, in which one liver is used for transplants for two recipients, and living donor liver transplantation, in which a portion of a healthy person's liver is removed and used as the allograft. Living donor liver transplantation for pediatric recipients involves removal of approximately 20% of the liver (Couinaud segments 2 and 3).

Immunosuppressive management

Like most other allografts, a liver transplant will be rejected by the recipient unless immunosuppressive drugs are used. The immunosuppressive regimens for all solid organ transplants are fairly similar, and a variety of agents are now available. Most liver transplant recipients receive corticosteroids plus a calcinuerin inhibitor such as tacrolimus or ciclosporin plus an antimetabolite such as Mycophenolate Mofetil.

Liver transplantation is unique in that the risk of chronic rejection also decreases over time, although recipients need to take immunosuppressive medication for the rest of their lives. It is theorized that the liver may play a yet-unknown role in the maturation of certain cells pertaining to the immune system. There is at least one study by Dr. Starzl's team at the University of Pittsburgh which consisted of bone marrow biopsies taken from such patients which demonstrate genotypic chimerism in the bone marrow of liver transplant recipients.

Graft rejection

After a liver transplantation, there are three types of graft rejection that may occur. They include hyperacute rejection, acute rejection and chronic rejection. Hyperacute rejection is caused by preformed anti-donor antibodies. It is characterized by the binding of these antibodies to antigens on vascular endothelial cells. Complement activation is involved and the effect is usually profound. Hyperacute rejection happens within minutes to hours after the transplant procedure. Unlike hyperacute rejection, which is B cell mediated, acute rejection is mediated by T cells. It involves direct cytotoxicity and cytokine mediated pathways. Acute rejection is the most common and the primary target of immunosuppressive agents. Acute rejection is usually seen within days or weeks of the transplant. Chronic rejection is the presence of any sign and symptom of rejection after 1 year. The cause of chronic rejection is still unknown but an acute rejection is a strong predictor of chronic rejections. Liver rejection may happen anytime after the transplant. Lab findings of a liver rejection include abnormal AST, ALT, GGT and liver function values such as prothrombin time, ammonia level, bilirubin level, albumin concentration, and blood glucose. Physical findings include encephalopathy, jaundice, bruising and bleeding tendency. Other nonspecific presentation are malaise, anorexia, muscle ache, low fever, slight increase in white blood count and graft tender.


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Results

Prognosis is quite good. However, those with certain illnesses may differ.[3] There is no exact model to predict survival rates; however, those with transplant have a 58% chance of surviving 15 years.[4] Failure from the new liver occurs in 10% to 15% of all cases. These percentages are contributed to by many complications. Early graft failure is probably due to preexisting disease of the donated organ. Others include technical flaws during surgery such as revascularization that may lead to a nonfunctioning graft.

Living donor transplantation

Living donor liver transplantation (LDLT) has emerged in recent decades as a critical surgical option for patients with end stage liver disease, such as cirrhosis and/or hepatocellular carcinoma often attributable to one or more of the following: long-term alcohol abuse, long-term untreated Hepatitis C infection, long-term untreated Hepatitis B infection. The concept of LDLT is based on (1) the remarkable regenerative capacities of the human liver and (2) the widespread shortage of cadaveric livers for patients awaiting transplant. In LDLT, a piece of healthy liver is surgically removed from a living person and transplanted into a recipient, immediately after the recipient’s diseased liver has been entirely removed.

Historically, LDLT began as a means for parents of children with severe liver disease to donate a portion of their healthy liver to replace their child's entire damaged liver. The first report of successful LDLT was by Dr. Christoph Broelsch at the University of Chicago Medical Center in November 1989, when two-year-old Alyssa Smith received a portion of her mother's liver.[5] Surgeons eventually realized that adult-to-adult LDLT was also possible, and now the practice is common in a few reputable medical institutes. It is considered more technically demanding than even standard, cadaveric donor liver transplantation, and also poses the ethical problems underlying the indication of a major surgical operation (hepatectomy) on a healthy human being. In various case series the risk of complications in the donor is around 10%, and very occasionally a second operation is needed. Common problems are biliary fistula, gastric stasis and infections; they are more common after removal of the right lobe of the liver. Death after LDLT has been reported at 0% (Japan), 0.3% (USA) and <1% (Europe), with risks likely to decrease further as surgeons gain more experience in this procedure.[6]

In a typical adult recipient LDLT, 55 to 70% of the liver (the right lobe) is removed from a healthy living donor. The donor's liver will regenerate approaching 100% function within 4–6 weeks and will almost reach full volumetric size with recapitulation of the normal structure soon thereafter. It may be possible to remove up to 70% of the liver from a healthy living donor without harm in most cases. The transplanted portion will reach full function and the appropriate size in the recipient as well, although it will take longer than for the donor. [1]

Living donors are faced with risks and/or complications after the surgery. Blood clots and biliary problems have the possibility of arising in the donor post-op, but these issues are remedied fairly easily. Although death is a risk that a living donor must be willing to accept prior to the surgery, the mortality rate of living donors in the United States is low. The LDLT donor's immune system does diminish as a result of the liver regenerating, so certain foods which would normally cause an upset stomach could cause serious illness.

Liver donor requirements

Any member of the family, parent, sibling, child, spouse or a volunteer can donate their liver. The criteria for a liver donation include:

  • Being in good health
  • Having a blood type that matches or is compatible with the recipient's
  • Having a charitable desire of donation without financial motivation
  • Being between 18 and 60 years old
  • Being of similar or bigger size than the recipient
  • Before one becomes a living donor, the donor has to undergo testing to ensure that the individual is physically fit. Sometimes CT scans or MRI are done to image the liver. In most cases, the work up is done in 2-3 weeks [7]

Complications

Living donor surgery is done at a major center. Very few individuals require any blood transfusions during or after surgery. Even though the procedure is very safe, all potential donors should know there is a 0-5 to 1 percent chance of death. Other risk of donating a liver include bleeding, infection, painful incision, possibility of blood clots and a prolonged recovery.[8] The vast majority of donors enjoy complete and full recovery within 2-3 months.


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Pediatric transplantation

In children living liver donor transplantation have become very accepted. The accessibility of adult parents who want to donate a piece of the liver for their children/infants has reduced the number of children who would have otherwise died waiting for a transplant. Having a parent as a donor also has made it a lot easier for children - because both patients are in the same hospital and can help boost each other's morale.[9]

Benefits

The advantages of living liver donor transplantation has several benefits over cadaveric donor transplantation including:

  • Transplant can be done on an elective basis because the donor is readily available
  • There are less possibilities for complications and death while waiting for a cadaveric organ donor
  • Because of donor shortages, UNOS has limited the cadaveric organ allocation to foreigners who seek medical help in the USA. However, with the availability of living donor transplantation, this will now allow foreigners a new opportunity to seek medical care in the USA

Screening for donors

The majority of liver transplantation centers in the USA have a superb record on long term survival. Living donor transplantation is a multidisciplinary approach. All living liver donors undergo medical evaluation. Every hospital which performs transplant have dedicated nurses that provide specific information about the procedure and answer questions that families may have. During the evaluation process, confidentially is assured on the potential donor. Every effort is made to ensure that organ donation is not made by coercion from other family members. The transplant team provides both the donor and family thorough counseling and support which continues until full recovery is made. [10]

All donors are assessed medically to ensure that they can undergo the surgery. Blood type of the donor and recipient must be compatible but not always identical. Other things assessed prior to surgery include the anatomy of the donor liver. However, even with mild variations in blood vessels and bile duct, surgeons today are able to perform transplantation without problems. The most important criteria for a living liver donor is to be in excellent health. [11]

Economic aspect

The medical expenses including work up, surgery and post operative recovery period are usually covered by the recipient's health insurance plans in most cases. There are also programs like the National Living Donor Assistance Center which provides financial assistance to help cover the cost of travel, accommodation and other expenses. This program also pays for postoperative trips including expenses for accompanying individuals. [12]

Controversy over eligibility for alcoholics

The high incidence of liver transplants given to those with alcoholic cirrhosis has led to a recurring controversy regarding the eligibility of such patients for liver transplant. The controversy stems from the view of alcoholism as a self-inflicted disease and the perception that those with alcohol-induced damage are depriving other patients who could be considered more deserving.[13]

الهامش

  1. ^ STARZL T, MARCHIORO T, VONKAULLA K, HERMANN G, BRITTAIN R, WADDELL W. "Homotransplantation Of The Liver In Humans". Surg Gynecol Obstet. 117: 659–76. PMID 14100514.CS1 maint: Multiple names: authors list (link)
  2. ^ Starzl TE, Klintmalm GB, Porter KA, Iwatsuki S, Schroter GP. (1981). "Liver transplantation with use of cyclosporin A and prednisone". New England Journal of Medicine. 305: 266–269. PMID 7017414.CS1 maint: Multiple names: authors list (link)
  3. ^ http://www.innovations-report.com/html/reports/medicine_health/report-22829.html
  4. ^ https://www.uktransplant.org.uk/ukt/statistics/presentations/pdfs/april_05/liver_life_expectancy.pdf
  5. ^ http://www.uchicagokidshospital.org/specialties/transplant/patient-stories/alyssa-liver.html
  6. ^ Umeshita K, Fujiwara K, Kiyosawa K; et al. (2003). "Operative morbidity of living liver donors in Japan". Lancet. 362 (9385): 687–90. doi:10.1016/S0140-6736(03)14230-4. PMID 12957090. Unknown parameter |month= ignored (help); Explicit use of et al. in: |author= (help)CS1 maint: Multiple names: authors list (link)
  7. ^ Who can be a Donor? - University of Maryland Medical Center, Retrieved on 2010-01-20.
  8. ^ Liver Transplant, Retrieved on 2010-01-20.
  9. ^ hat I need to know about Liver Transplantation, National Digestive Diseases Information Clearinghouse (NDDIC), Retrieved on 2010-01-20.
  10. ^ Liver Donor: All you need to know, Retrieved on 2010-01-20.
  11. ^ Liver Transplant Program And Center for Liver Disease, University of Southern California Department of Surgery, Retrieved on 2010-01-20.
  12. ^ Liver Transplants, University of California, San Francisco, Retrieved on 2010-01-20.
  13. ^ http://www.psychologytoday.com/blog/mouse-man/200902/do-alcoholics-deserve-liver-transplants

Further reading

  • Eghtesad B, Kadry Z, Fung J (2005). "Technical considerations in liver transplantation: what a hepatologist needs to know (and every surgeon should practice)". Liver Transpl. 11 (8): 861–71. doi:10.1002/lt.20529. PMID 16035067.CS1 maint: Multiple names: authors list (link)
  • Adam R, McMaster P, O'Grady JG, Castaing D, Klempnauer JL, Jamieson N, Neuhaus P, Lerut J, Salizzoni M, Pollard S, Muhlbacher F, Rogiers X, Garcia Valdecasas JC, Berenguer J, Jaeck D, Moreno Gonzalez E (2003). "Evolution of liver transplantation in Europe: report of the European Liver Transplant Registry". Liver Transpl. 9 (12): 1231–43. doi:10.1016/j.lts.2003.09.018. PMID 14625822.CS1 maint: Multiple names: authors list (link)
  • Reddy S, Zilvetti M, Brockmann J, McLaren A, Friend P (2004). "Liver transplantation from non-heart-beating donors: current status and future prospects". Liver Transpl. 10 (10): 1223–32. doi:10.1002/lt.20268. PMID 15376341.CS1 maint: Multiple names: authors list (link)
  • Tuttle-Newhall JE, Collins BH, Desai DM, Kuo PC, Heneghan MA (2005). "The current status of living donor liver transplantation". Curr Probl Surg. 42 (3): 144–83. doi:10.1067/j.cpsurg.2004.12.003. PMID 15859440.CS1 maint: Multiple names: authors list (link)
  • Martinez OM, Rosen HR (2005). "Basic concepts in transplant immunology". Liver Transpl. 11 (4): 370–81. doi:10.1002/lt.20406. PMID 15776458.
  • Krahn LE, DiMartini A (2005). "Psychiatric and psychosocial aspects of liver transplantation". Liver Transpl. 11 (10): 1157–68. doi:10.1002/lt.20578. PMID 16184540.
  • Nadalin S, Malagò M, et al. Current trends in live liver donation. Transpl. Int. 2007;20:312-30.
  • Vohra V. Liver transplantation in India. Int Anesthesiol Clin. 2006;44:137-49.
  • Strong RW. Living-donor liver transplantation: an overview. J Hepatobiliary Pancreat Surg. 2006;13:370-7.
  • Fan ST. Live donor liver transplantation in adults. Transplantation. 2006;82:723-32.

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