GGT levels are normal As a consequence of hypersplenism from portal hypertension, the platelet count is typically low Initial imaging with Doppler ultrasound can be confirmed with CT, MRI, or angiography Treatment for portal vein obstruction depends on the etiology Balloon dilation with stent placement may be used to repair portal vein stenosis For PVT, anticoagulation or thrombolysis may be attempted When amenable, surgical bypass or shunting to preserve flow through the liver, such as a Meso-Rex shunt, is preferred In select cases, retransplantation may be necessary Hepatic Vein Obstruction Hepatic vein obstruction is a rare complication that occurs more often with technical variant grafts It is typically associated with ascites and protein-losing enteropathy which presents with diarrhea and hypoalbuminemia Ultrasound with Doppler is the imaging of choice when a hepatic vein obstruction is suspected A venogram should be used to confirm hepatic vein obstruction and venoplasty has been successful at restoring hepatic venous flow Cardiac Vascular Complications Cardiac transplant recipients not typically present de novo with postsurgical vascular issues Recipients who were transplanted for failed palliation of congenital heart disease may have stenotic vessels or anastomotic sites that become narrow over time Such findings are typically identified during the course of routine cardiac transplant follow-up and addressed electively SURGICAL COMPLICATIONS CLINICAL PEARLS AND PITFALLS Surgical complications of liver transplantation are typically related to vascular and biliary anastomoses and an ultrasound with Doppler should be obtained if there is suspicion of a surgical complication Surgical complications post heart transplant are typically not occult, and are not likely to present beyond the early postoperative period Surgical complications of renal transplant include urinary leak or urinary tract obstruction The high doses of immunosuppression used in the immediate postoperative period present a risk of wound infection, and certain medications such as sirolimus may impede wound healing Overall, most surgical complications are related to the vascular anastomoses, which are described in more detail in previous sections Biliary anatomy can complicate liver transplantation and recipients who require more than one biliary anastomosis are at increased risk for biliary leaks In addition, graft ischemia whether from increased cold ischemia time or poor vascular reperfusion can lead to biliary strictures Patients with surgical complications may present with a variety of symptoms including fever, hemodynamic instability, or rise in liver enzymes Initial management should focus on hemodynamic stabilization and obtaining directed imaging such as an ultrasound with Doppler Incisional hernia may occur in 5% to 18% of liver transplant recipients and occur more frequently if there is not a primary fascial closure Incisional hernias can be diagnosed on physical examination and assessment of reducibility is imperative An incarcerated or nonreducible hernia requires surgical consultation although most can be medically managed without need for surgery In renal transplant patients, urinary leak occurs due to ureteral necrosis, bladder injury, or obstruction Urinary obstruction is thought to be caused by clot in the urinary tract or postoperative edema It is detected as hydronephrosis on renal ultrasound IMMUNOSUPPRESSANT MEDICATION–RELATED COMPLICATIONS CLINICAL PEARLS AND PITFALLS Long-term use of immunosuppression medications has been associated with an increased risk for renal insufficiency, hypertension, diabetes, hyperlipidemia, obesity, lymphoproliferative disease, and metabolic syndrome Common side effects of CNIs include hypertension, renal insufficiency, lymphoproliferative disease, and seizures Most side effects improve with minimizing doses Sirolimus is being used more frequently as a renal-sparing primary immunosuppressive agent with the main side effects being mouth ulcers, marrow suppression, and hyperlipidemia Sirolimus is used in heart transplant recipients as adjunct therapy for those patients with coronary artery disease, chronic rejection, or antibody-mediated rejection There is potential for complications with all posttransplant medication regimens, including both from immunosuppression medications as well as other routine prophylactic medications including aspirin, ganciclovir, trimethoprim sulfamethoxazole, and ranitidine ( Table 125.4 ) The two main classifications of immunosuppressant medications used are CNIs (cyclosporine and tacrolimus) and the purine antagonists or antimetabolites (azathioprine and mycophenolate mofetil) The typical immunosuppressant medications used in liver transplantation include corticosteroids, CNIs, and antimetabolites Similarly, heart transplant recipients receive maintenance immunosuppression with a CNI and a purine antagonist; most programs have moved away from chronic steroid use Long-term use of immunosuppression medications has been associated with an increased risk for renal insufficiency, hypertension, diabetes, hyperlipidemia, lymphoproliferative disease/lymphoma, increased infection risk, obesity, and metabolic syndrome TABLE 125.4 ADVERSE EFFECTS OF IMMUNOSUPPRESSIVE AGENTS a Corticosteroids are used in both the initial immunosuppression setting as well as for the treatment of acute cellular rejection Corticosteroid therapy decreases inflammatory response by preventing the chemotaxis and recruitment of mediating lymphocytes Relatively common acute adverse effects include hypertension, hyperglycemia (sometimes requiring insulin), psychosis, and joint pain Chronic adverse effects include the Cushing syndrome, bone demineralization, linear growth delay/arrest, adrenal suppression, and cataracts CNIs including tacrolimus and cyclosporine are currently the primary longterm immunosuppressant agents for pediatric liver transplant recipients Common side effects of tacrolimus include hyperglycemia (sometimes requiring insulin), anorexia, hypertension, headache, increased creatinine, and renal electrolyte wasting (particularly magnesium and potassium) Less common adverse effects of tacrolimus include dermatologic diseases, such as eczema, common warts (the severity of which can range from mild to disfiguring), and neurotoxicity (seizures) Many of these side effects are dose dependent Adverse effects of cyclosporine are similar to those of tacrolimus, with hypertension, renal injury, infection, skin problems, PTLD, and seizures Cyclosporine further causes cosmetic changes including hirsutism, coarsening of facial features, and gingival hyperplasia; these findings are not present with tacrolimus use Renal function is a primary concern as CNIs contribute to both acute and chronic posttransplant renal dysfunction The CNIs, as well as the purine inhibitors, enhance skin sensitivity to UV irradiation; as such, all patients on immunosuppression are cautioned to use high SPF sun screen/sun block and cover up when in the sun Mycophenolate is an ester of mycophenolic acid with lymphocytic antiproliferative properties that selectively inhibits proliferation of B and T lymphocytes by inhibiting de novo purine nucleotide synthesis Mycophenolate is used as a short-term or as maintenance adjuvant immunosuppressive therapy Common adverse effects include gastrointestinal symptoms, such as diarrhea and cramping, and marrow suppression Other effects include vomiting, anorexia, leukopenia, anemia, and infection Azathioprine can be used as an adjuvant immunosuppressive therapy in combination with a CNI and/or corticosteroid therapy Azathioprine is rapidly converted to 6-mercaptopurine, the active form of the drug, which acts as a lymphocytic antiproliferative by inhibition of purine synthesis The most common adverse effect is myelosuppression Idiosyncratic reactions include drug fever, hepatotoxicity, and pancreatitis and there is also an increased risk of infection Sirolimus is a newer immunosuppressive medication with growing indications in children Sirolimus inhibits T-lymphocyte activation and proliferation in response to antigenic and cytokine stimulation Sirolimus has been used in the pediatric transplant population as a single agent or in combination with CNIs It is ... including tacrolimus and cyclosporine are currently the primary longterm immunosuppressant agents for pediatric liver transplant recipients Common side effects of tacrolimus include hyperglycemia (sometimes... proliferation in response to antigenic and cytokine stimulation Sirolimus has been used in the pediatric transplant population as a single agent or in combination with CNIs It is