After completion of the vascular anastomoses, drainage of a transplanted pancreas is accomplished by anastomosis to:
Over the years, different surgical techniques have been described for:
For the secretions, the two most common techniques are drainage of the duodenal segment to the bladder (bladder drainage) or to the small bowel (enteric drainage) (Figs. below). For venous drainage, systemic venous drainage is preferred over portal venous drainage.
Whole-organ transplant with systemic vein and bladder exocrine drainage.
All of the following are absolute contraindications in considering a candidate for orthotopic cardiac transplantation EXCEPT:
In general terms, contraindications to a liver transplant include insufficient cardiopulmonary reserve, uncontrolled malignancy or infection, and refractory noncompliance. Older age is only a relative contraindication: carefully selected recipients older than 70 years can achieve satisfactory outcomes. Patients with reduced cardiopulmonary reserve are unlikely to survive a liver transplant. Candidates should have a normal ejection fraction. If coronary arterial disease is present, they should undergo revascularization pretransplant. Severe chronic obstructive pulmonary disease (COPD) with oxygen dependence is a contraindication. Severe pulmonary hypertension with a mean pulmonary artery pressure greater than 35 mm Hg that is refractory to medical therapy is also a contraindication. Candidates with pulmonary hypertension should be evaluated with a right heart catheterization.
Heart transplant donors and recipients are matched using the following criteria EXCEPT:
Once a potential deceased donor is identified, the surgeon reviews the status report and screening examination results. The donor is initially matched to the recipient per the recipient's status on the UNOS waiting list, the size match, and the blood type. Results of the donor's serologic testing, echocardiography, chest X-ray, hemodynamic testing, and possibly coronary artery evaluation are assessed, in order to determine whether or not the donor's heart can withstand up to 4 hours of cold ischemic time during procurement, transport, and surgery.
Required laboratory tests in evaluation of a patient under consideration for heart transplantation include all of the following EXCEPT:
Pretransplant, both candidates and potential donors are evaluated to ensure their suitability for the procedure. Transplant candidates undergo echocardiography, right and left heart catheterization, evaluation for any undiagnosed malignancies, laboratory testing to assess the function of other organs (such as the liver, kidneys, and endocrine system), a dental examination, psychosocial evaluation, and appropriate screening (such as mammography, colonoscopy, and prostate-specific antigen testing). Once the evaluation is complete, the selection committee determines, at a multidisciplinary conference, whether or not a heart transplant is needed and is likely to be successful. Transplant candidates who meet all of the center's criteria are added to the waiting list, according to the UNOS criteria, which are based on health status.
Immunologic rejection is mediated by the recipient's:
Transplants between genetically nonidentical persons lead to recognition and rejection of the organ by the recipient's immune system, if no intervention is undertaken. The main antigens responsible for this process are part of the major histocompatibility complex (MHC). In humans, these antigens make up the HLA system. The antigen-encoding genes are located on chromosome 6. Two major classes of HLAs are recognized. They differ in their structure, function, and tissue distribution. Class I antigens (HLA-A, HLA-B, and HLA-C) are expressed by all nucleated cells. Class II antigens (HLA-DR, HLA-DP, and HLA-DQ) are expressed by antigen presenting cells (APCs) such as B lymphocytes, dendritic cells, macrophages, and other phagocytic cells. The principal function of HLAs is to present the fragments of foreign proteins to T lymphocytes. This leads to recognition and elimination of the foreign antigen with great specificity. HLA molecules play a crucial role in transplant recipients as well. They can trigger rejection of a graft via two different mechanisms. The most common mechanism is cellular rejection, in which the damage is done by activated T lymphocytes.
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