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Amadeo Marcos

Publications and source records attributed to Amadeo Marcos.

46 records · Page 3Linked to original sources
PubMed2003

Hypophosphatemia after 95 right-lobe living-donor hepatectomies for liver transplantation is not a significant source of morbidity.

BACKGROUND: Hypophosphatemia appears to be a universal event after right hepatic lobectomy for live-donor adult liver transplantation according to one report. Because hypophosphatemia appears to contribute to increased postoperative complications, routine hyperalimentation with supratherapeutic levels of phosphorus was advocated. METHODS: From July 2000 to May 2002, we performed 95 right-lobe living-donor hepatectomies for 95 adult liver-transplant recipients, the largest single institutional experience. We reviewed our data that were collected prospectively. RESULTS: We did not find profound hypophosphatemia (<1.0 mg/dL) to be prevalent in our donors. At least six (6.3%) donors did not have postoperative hypophosphatemia. In addition, there appears to be no increased morbidity related to hypophosphatemia when aggressively corrected with intravenous or oral phosphates in our group of donors that underwent right-lobe hepatectomies. CONCLUSIONS: We, therefore, cannot endorse the routine administration of hyperalimentation with supratherapeutic phosphorus because of its potential morbidity.

Adult↗
PubMed2003

Pregnancy after liver transplantation with tacrolimus immunosuppression: a single center's experience update at 13 years.

BACKGROUND: Chronic liver disease often leads to amenorrhea in women of childbearing age. There are several reports of successful pregnancy after liver transplantation (LTx) with cyclosporine A immunosuppression. Tacrolimus has been increasingly used in solid-organ transplantation, and the effect of the drug on pregnancy is still of interest to clinicians. This study updates our single-center experience. METHODS: All pregnancies after LTx with tacrolimus immunosuppression were followed prospectively. Patients' clinical courses during pregnancy and labor along with gestational period and birth weight were catalogued. Changes in liver function, renal function, and immunosuppression also were recorded. The birth weight percentile was calculated on the basis of the gestational period using a standard chart. RESULTS: Thirty-seven mothers delivered 49 babies. Three mothers delivered three times, and six mothers delivered two times. Thirty-six mothers (97%) survived the pregnancy, and 36 allografts (97%) survived. The one death and graft loss was in a patient who demonstrated infra-aortic arterial graft, which clotted by the gravid uterus during labor. The patient developed a gangrenous liver and died before she could undergo retransplantation. The mean gestational period was 36.4+/-3.2 weeks, excluding two premature deliveries at 23 and 24 weeks gestation. Twenty-two babies (46.9%) were delivered by cesarean section, and the other babies were delivered vaginally. In addition to the two premature babies, one baby, who was born to a mother with Alagille syndrome, died from congenital birth defects. The rest of the newborns survived. The mean birth weight was 2,797+/-775 g, with 38 babies (78%) weighing more than 2,000 g. The mean birth weight percentile to gestational period was 54+/-23. Four babies (8.5%) had a birth weight percentile of less than 25, and 28 babies (59.6%) had a birth weight percentile greater than 50. Twelve patients demonstrated an increase in hepatic enzymes without jaundice during the pregnancy. All of them responded to augmentation of immunosuppression. CONCLUSION: The present report reconfirms the safety of tacrolimus during pregnancy after LTx. Preterm delivery and low birth weight seem to be a persistent problem in all solid-organ transplantation under any form of immunosuppression. However, toxemia of pregnancy and new onset of hypertension seem to be have a low occurrence with the use of tacrolimus.

Abnormalities, Multiple↗
PubMed2003

Tolerogenic immunosuppression for organ transplantation.

BACKGROUND: Insight into the mechanisms of organ engraftment and acquired tolerance has made it possible to facilitate these mechanisms, by tailoring the timing and dosage of immunosuppression in accordance with two therapeutic principles: recipient pretreatment, and minimum use of post-transplant immunosuppression. We aimed to apply these principles in recipients of renal and extrarenal organ transplants. METHODS: 82 patients awaiting kidney, liver, pancreas, or intestinal transplantation were pretreated with about 5 mg/kg of a broadly reacting rabbit antithymocyte globulin during several hours. Post-transplant immunosuppression was restricted to tacrolimus unless additional drugs were needed to treat breakthrough rejection. After 4 months, patients on tacrolimus monotherapy were considered for dose-spacing to every other day or longer intervals. FINDINGS: We frequently saw evidence of immune activation in graft biopsy samples, but unless this was associated with graft dysfunction or serious immune destruction, treatment usually was not intensified. Immunosuppression-related morbidity was virtually eliminated. 78 (95%) of 82 patients survived at 1 year and at 13-18 months. Graft survival was 73 (89%) of 82 at 1 year and 72 (88%) of 82 at 13-18 months. Of the 72 recipients with surviving grafts, 43 are on spaced doses of tacrolimus monotherapy: every other day (n=6), three times per week (11), twice per week (15), or once per week (11). INTERPRETATION: The striking ability to wean immunosuppression in these recipients indicates variable induction of tolerance. The simple therapeutic principles are neither drug-specific nor organ-specific. Systematic application of these principles should allow improvements in quality of life and long-term survival after organ transplantation.

Antilymphocyte Serum↗
PubMed2003

Hepatic arterial reconstruction in 95 adult right lobe living donor liver transplants: evolution of anastomotic technique.

The success of adult right-lobe living donor liver transplants (RLDLT) would not have been possible without the experience of the early pioneers of pediatric living donor liver transplants (LDLT). Our experience with 95 RLDLTs from July, 2000 to May, 2002 at a single institution is reported with specific emphasis on arterial reconstruction. The evolution of technique using the autogenous Y extension graft and the reverse extension bifurcated graft for arterial revascularization, which we believe has reduced the incidence of hepatic artery thrombosis, is described. Outcome and the incidence of hepatic artery thrombosis are reported.

Adult↗
PubMed2003

Effect of coadministered lopinavir and ritonavir (Kaletra) on tacrolimus blood concentration in liver transplantation patients.

With the advent of highly active antiretroviral therapy (HAART), HIV positivity is no longer a contraindication for liver transplantation. Some of the antiretroviral agents, particularly protease inhibitors (e.g., ritonavir, indinavir, and nelfinavir) have been described as potent inhibitors of the metabolism of certain immunosuppressive drugs. In this article we describe a profound interaction between tacrolimus and Kaletra (Abbott Laboratories, Chicago, IL) (a combination of lopinavir and ritonavir) in 3 liver transplantation patients. Patient 1, who was maintained on a 5 mg twice daily dose of tacrolimus with a trough blood concentration around 10.6 ng/mL, required only 0.5 mg of tacrolimus per week after addition of Kaletra to achieve similar tacrolimus blood concentrations, with a half-life of 10.6 days. In patient 2, the area under the blood concentration versus time curve for tacrolimus increased from 31 ng/mL/h to 301 ng/mL/h after addition of Kaletra, with a corresponding half-life of 20 days. When the patient was subsequently switched to nelfinavir, the half-life decreased to 10.3 days. Patient 3, who was maintained with 4 to 8 mg/d of tacrolimus and a corresponding blood concentration of 10 ng/mL before Kaletra, required a tacrolimus dose of 1 mg/wk and tacrolimus concentrations of 5 ng/mL with Kaletra. In conclusion, a combination of lopinavir and ritonavir led to a much more profound increase in tacrolimus blood concentrations than use of single protease inhibitor, nelfinavir. A tacrolimus dose of less than 1 mg/wk may be sufficient to maintain adequate blood tacrolimus concentrations in patients on Kaletra. Patients may not need a further dose of tacrolimus for 3 to 5 weeks depending on liver function when therapy with Kaletra is initiated. Great caution is required in the management of tacrolimus dosage when Kaletra is introduced or withdrawn in HIV-positive patients after liver transplantation, particularly in the presence of hepatic dysfunction.

Adult↗
PubMed2003

Kidney transplantation under a tolerogenic regimen of recipient pretreatment and low-dose postoperative immunosuppression with subsequent weaning.

OBJECTIVE: The purpose of this work was to perform kidney transplantation under a regimen of immunosuppression that facilitates rather than interferes with the recently defined mechanisms of alloengraftment and acquired tolerance. SUMMARY BACKGROUND DATA: In almost all centers, multiple immunosuppressive agents are given in large doses after kidney transplantation in an attempt to reduce the incidence of acute rejection to near zero. With the elucidation of the mechanisms of alloengraftment and acquired tolerance, it was realized that such heavy prophylactic immunosuppression could systematically subvert the clonal exhaustion-deletion that is the seminal mechanism of tolerance. In addition, it has been established that the rejection response can be made more readily treatable by pretransplant immunosuppression. Consequently, we conducted kidney transplantation in compliance with 2 therapeutic principles: recipient pretreatment and the least possible use of posttransplant immunosuppression. METHODS: One-hundred fifty unselected renal transplant recipients with a mean age of 51 +/- 15 years and multiple risk factors had pretreatment with approximately 5 mg/kg of rabbit antithymocyte globulin (Thymoglobulin) in the hours before transplantation, under covering bolus doses of prednisone to prevent cytokine reactions. Minimal posttransplant immunosuppression was with tacrolimus monotherapy to which steroids or other agents were added only for the treatment of rejection. At or after 4 months after transplant, spaced-dose weaning from tacrolimus monotherapy was begun in patients who had exhibited a satisfactory course. RESULTS: One-year actuarial patient and graft survival was 97% and 92%, respectively. Although the incidence of early acute rejection was 37%, only 7% required prolonged treatment with any agent other than tacrolimus. After a follow-up of 6 to 21 months, the mean serum creatinine in patients with functioning grafts is 1.8 +/- 1.0 mg/dL. Seventy-three percent of the patients met the criteria for spaced weaning. Although rejection episodes occasionally required restoration of daily treatment, 94 (63%) of the 150 patients currently receive tacrolimus in spaced doses ranging from every other day to once a week. CONCLUSIONS: With this approach to immunosuppression, it has been possible to avoid early posttransplant overimmunosuppression and thereby to promote the evolution of a degree of partial tolerance sufficient to undertake substantial dose reduction. The strategy, which is applicable for all organ grafts, constitutes a paradigm shift in transplant management at our center.

Adult↗
PubMed2002

One hundred consecutive hepatic biopsies in the workup of living donors for right lobe liver transplantation.

Living donor liver transplantation allows an increasing number of patients with end-stage liver disease the opportunity for effective treatment in the face of a critical shortage of cadaveric organs. Hepatic steatosis decreases functional graft mass and may contribute to graft dysfunction. Screening liver biopsy allows accurate quantitation of hepatic fat, but is an invasive procedure that is not universally employed in the evaluation of living donors. We studied 100 consecutive prospective right lobe living donors, all evaluated with liver biopsy, imaging studies, and various clinical parameters. The accuracy and predictive value of body mass index (BMI) and imaging were compared with biopsy in determining the amount of hepatic fat. There were no complications to biopsy, with 33% showing some degree of steatosis. BMI correlated only weakly with biopsy, with 73% of overweight (BMI > 25) donors having little or no hepatic fat. Imaging was only 12% sensitive to small amounts (5% to 10%) of fat, with increasing sensitivity to more severe steatosis. Imaging diagnosed steatosis in 2 donors without hepatic fat and failed to identify a candidate denied with biopsy-proven 30% steatosis. Conversely, 9% of candidates with BMIs of 25 or less had 10% or greater steatosis. Moreover, three candidates were denied surgery because biopsy detected occult liver disease. Accurate quantification of hepatic fat is not afforded by BMI and imaging studies alone. Screening liver biopsy has a low complication rate and may serve to increase donor safety. Biopsy is essential in identifying donor grafts at risk for poor recipient outcome while maximizing the donor pool.

Adipose Tissue↗
PubMedDate not supplied

Comparison of two different techniques of reperfusion in adult orthotopic liver transplantation.

UNLABELLED: The aim of this study was to determine the impact of two reperfusion techniques on the peri-operative hemodynamic changes and early post-operative graft function of adult patients undergoing orthotopic liver transplantation. MATERIAL AND METHODS: From June 2003 to May 2004, 50 consecutive liver transplants were performed and divided into two groups: group A, 25 patients, portal vein flush with 500 cm(3) of Ringer's lactate without vena caval venting. Group B, 25 patients, vena caval venting with no portal vein flush. Donor and recipient characteristics were similar in both groups. Sixty-four different parameters were analyzed, and Pearson's chi(2) test and t-test were used for statistical analysis, p<or=0.05. RESULTS: One patient (4%) in group B experienced a post-reperfusion syndrome (PRS). Pearson's chi(2) test found a significant relationship between the analyzed parameters and the two different reperfusion techniques for 10 parameters (t-test analysis showed a significant difference between the two groups in favor of group A). CONCLUSIONS: In our transplant center, portal vein flush without vena caval venting provided a lower incidence of hemodynamic changes in the peri-operative period after liver transplantation and earlier recovery of the graft function.

Adolescent↗