Total hip replacement in renal transplant patients

Avascular necrosis of the femoral head creates considerable morbidity in successful renal transplant recipients who are generally young and expect active lifestyles. Total hip replacement is considered the treatment of choice in these patients, but surgeons may be wary because of a supposed increase in the risk of infection and other complications. A review of the literature reveals that cemented hip arthroplasty provides good to excellent functional outcomes for renal transplant patients. Most authors have found that the risk of infection is not increased despite chronic immunosuppression, but the rates of general complications are and should be anticipated and treated. There is a high rate of early failure in these patients because of their young age and diffuse osteopenia as a result of secondary hyperparathyroidism related to the underlying renal disease and chronic steroid use. Recent studies have found that despite decreased bone stock in these patients, porous-coated prostheses are not contraindicated.     

Dacron vascular grafts in renal transplant patients

Dacron vascular grafts were used for limb salvage in three patients receiving renal transplants. The patients had survival of the limbs and subsequently received immunosuppression therapy with azathioprine and prednisone without untoward effects on the vascular prosthesis.     

Everolimus in pediatric de nova renal transplant patients

BACKGROUND: The steady-state pharmacokinetics of everolimus were longitudinally assessed in pediatric de novo kidney allograft recipients during a 6-month period. METHODS: Nineteen patients received everolimus 0.8 mg/m2 (maximum 1.5 mg) twice daily as a dispersible tablet in water in addition to cyclosporine and corticosteroids. Everolimus and cyclosporine trough concentrations were obtained on days 3, 5, 6, and 7 and at months 1, 2, 3, and 6; an everolimus pharmacokinetic profile was obtained on day 7 and month 3. RESULTS: There were 9 boys and 10 girls with a median age of 9.9 (range, 1-16) years. Steady-state pharmacokinetic parameters were as follows (median, range): C(min) (trough level), 4.7 (2.3- 9.5) ng/mL; peak concentration, 13.5 (5.9-22.2) ng/mL; area under the concentration-time curve (AUC), 77 (53-147) ng x hr/mL; and apparent oral clearance, 10.2 (5.5-15.6) L/hr/m2. Clearance (unadjusted for demographic factors) was positively correlated with age (r=0.66), body surface area (r=0.68), and weight (r=0.67). There were no trends in C(min) or AUC versus patient age when everolimus was dosed on a mg/m2 basis. Everolimus C(min) were stable over time with median values of 3.9, 3.4, and 3.1 ng/mL at months 1, 3, and 6, respectively. Intra- and interpatient variability in AUC was 29% and 35%, similar to that in adults. During the observation period, eight patients maintained stable AUCs and nine patients had increases or decreases, generally between 30% and 50% compared with the AUC at week 1. The concurrent median cyclosporine C(min) were generally at the lower end of conventional target ranges: 156, 83, and 69 ng/mL at months 1, 3, and 6, respectively. There were no graft losses and only three mild or moderate, reversible rejection episodes occurred. Everolimus was generally safe and well tolerated. CONCLUSIONS: These data support the use of body surface area-adjusted dosing for everolimus in pediatric patients. Although exposure is generally stable over time with moderate variability in AUC, therapeutic monitoring would be a helpful adjunct for individualizing everolimus exposure, assessing regimen adherence, and adjusting doses as the child matures.     

Enteric-coated mycophenolate sodium in de novo pediatric renal transplant patients

Data on the use of enteric-coated mycophenolic acid (EC-MPS) in pediatric transplantation cases are scarce. We undertook a 12-month, multicenter, open-label pilot study in which 16 de novo renal transplant patients aged 5–16 years received EC-MPS with cyclosporine A microemulsion (CsA-ME), steroids, and anti-interleukin-2 receptor antibody induction. The mean dose of EC-MPS was 916 ± 93 mg/m² per day during weeks 1–2, 810 ± 193 mg/m² per day during months 3–6, and 827 ± 153 mg/m² per day during months 6–12. The mean CsA C₂ level exceeded target range up to month 6 post-transplant. Efficacy failure (biopsy-proven acute rejection, graft loss, death or loss to follow-up) occurred in two patients: one patient with primary non-function underwent nephrectomy, and one patient experienced biopsy-proven acute rejection (Grade 1B, day 344) following EC-MPS dose reduction. There were no deaths. Creatinine clearance (Schwartz) was 103 ± 30 mL/min per 1.73 m² at month 6 and 100 ± 16 mL/min per 1.73 m² at month 12. The majority of adverse events were mild or moderate (101/126, 80.2%). In this pilot study, EC-MPS 450 mg/m² administered twice daily with CsA, steroids, and interleukin-2 antibody induction resulted in a low rate of rejection with good renal function in a pediatric population. However, a larger, controlled trial is required to confirm these results.     

H1N1 vaccination in pediatric renal transplant patients

Background

Solid organ transplant recipients undergoing immunosuppressive therapy are considered to be at high risk of serious infectious complications. In 2009, a new influenza pandemic caused serious infections and deaths, especially among children and immunocompromised patients. Herein we have reported the safety and efficacy of a single-shot monovalent whole-virus vaccine against H1N1 infection in the pediatric renal transplant population.

Methods

In November and December 2009, we vaccinated 37 renal transplant children and adolescents and measured their antibody responses. Seroprotection, seroconversion, and seroconversion factors were analyzed at 21 days after vaccination.

Results

None of the vaccinated patients experienced vaccine-related side effects. None of the patients had an H1N1 influenza infection after vaccination. All of the patients showed elevations in antibody titer at 21 days after vaccination. In contrast, only 29.72% of the patients achieved a safe seroprotection level and only 18.75% a safe seroconversion rate. More intense immunosuppressive treatment displayed negative effect on seroprotection and seroconversion, and antibody production significantly increased with age. No other factor was observed to influence seroprotection.

Conclusions

We recommend vaccination of children and adolescent renal transplant recipients against H1N1 virus. However, a single shot of vaccine may not be sufficient; to achieve seroprotection, a booster vaccination and measurement of the antibody response are needed to assure protection of our patients.     

Anemia in pediatric renal transplant recipients

The aim of this study was to establish the prevalence of anemia in stable pediatric renal transplant recipients and to examine the association of anemia with renal function, immunosuppressants, angiotensin converting enzyme inhibitors, and growth, as well as iron, vitamin B₁₂, and folate stores. This is a cross-sectional study of the 50 renal transplant recipients currently followed at our center. Patient data were collected regarding hematological parameters, growth, medications, renal function, underlying renal disease, delayed graft function, episodes of rejection, and iron or erythropoietin therapy post transplantation. The mean hemoglobin level (Hb) was 110 g/l and the overall prevalence of anemia was 60%, including 30% who were severely anemic (Hb<100 g/l). There was a high rate of iron deficiency (34%) and serum iron was the parameter of iron metabolism most closely associated with anemia. Hb in patients with low serum iron was 90.7 g/l versus 114.4 g/l in those with normal serum iron (P<0.01). Both univariate and multiple linear regression determined tacrolimus dose and creatinine clearance to be significant factors associated with anemia. Tacrolimus dose correlated with a 10 g/l reduction in Hb for every increase of tacrolimus dose of 0.054 mg/kg per day (P=0.001). The dose of mycophenolate was positively correlated with Hb, but this was likely to be confounded by our practice of dose reduction in the setting of anemia. Angiotensin converting enzyme inhibitor use was not associated with anemia. Severely anemic patients tended to be shorter, with a mean Z-score for height of –1.8 compared with –0.9 for those with normal Hb (P=0.02). Anemia is a significant and common problem in pediatric renal transplant patients. Deteriorating renal function is an important cause, but other factors like iron deficiency and immunosuppression are involved. Definition of iron deficiency is difficult and serum iron may be a valuable indicator. Medication doses, nutritional status, need for erythropoietin and iron, as well as poor graft function and growth require systematic scrutiny in the care of the anemic renal transplant recipient.     

Gout in pediatric renal transplant recipients

Clinical gout has rarely been described after pediatric renal transplantation (RTx), although asymptomatic hyperuricemia is common in these patients. We describe three male pediatric patients who presented with gouty arthritis 7–8.5 years following RTx. Since receiving allopurinol, all patients had been free of gouty symptoms. To prevent severe bone marrow depletion, the dosage of azathioprine, an immunosupressant drug, was reduced by 50% to prevent interaction with allopurinol. Because atypical presentation of gout can occur, a high index of suspicion is needed to allow appropriate diagnosis of this disease in patients with skeletal pain after RTx.     

Growth in pediatric renal transplant recipients

One of the fundamental challenges in managing pediatric renal transplant recipient is to ensure normal growth and development. The goal of renal transplant is not just to prolong life but to optimize quality of life. Short stature during childhood may be associated with academic underachievement and development of comorbidities such as attention deficit hyperactivity disorder, learning disability, and mood disorders. The most important factors affecting growth are use of corticosteroids, allograft function, and age and height deficit at the time of transplant. Aggressive conservative management of chronic renal failure and early use of growth hormone therapy will help in optimizing height at time of transplant. Early transplant, steroid minimization or withdrawal, and growth hormone therapy will help in achieving normal adult height in a majority of renal post transplant population. Steroid avoidance to achieve good growth still needs to be validated.     

Symptomatic cholelithiasis in pediatric renal transplant recipients

We report two cases of symptomatic cholelithiasis in pediatric renal transplant recipients immunosuppressed with cyclosporine (CsA), prednisone and azathioprine. CsA was present in the bile and in the cholesterol gallstones of one patient. The diagnosis of cholelithiasis was established in both cases by abdominal ultrasound examination.     

Activated protein C resistance in patients with peripheral vascular disease

Purpose: The frequency of activated protein C (APC) resistance, caused by factor V R506Q gene mutation and abnormal APC ratio, in patients with peripheral vascular diseases was analyzed. Methods: All patients electively admitted to the vascular ward unit of our tertiary care academic medical center from January 1995 through October 1996 (n = 679) were prospectively analyzed using an APC-resistance screening test to determine the frequency of abnormal APC ratio (≤2.6). Baseline activated partial thromboplastin time (APTT) and its prolongation after the addition of a standard amount of APC were determined. The factor V R506Q gene mutation (Leiden) was analyzed in patients with an APC ratio less than 3.0. Statistical comparisons were made to an age-matched control population (n = 278). Results: The factor V Leiden gene mutation or abnormal APC ratio was detected in 154 of the patients (22.7%), compared with 34 of 278 the control subjects (12.2%; t = 13.65; P < .001). The factor V Leiden gene mutation was found in 102 patients (15.2%), compared with 29 control subjects (10.4%; t = 4.64; P < .05); an abnormal APC ratio was found in 132 patients (19.8%), compared with 26 (9.8%) of controls (t = 14.56; P <.001). The frequency of the factor V Leiden gene mutation was significantly increased in patients with femoro-popliteal occlusive disease (n = 126), to 21.6% (t = 16.94; P<.001), and venous disease (n = 50), to 36.0% (t = 20.93; P < .001). Overall, 63% of the patients with abnormal APC ratios tested positive for the factor V Leiden gene mutation. A significantly increased frequency of APC resistance was demonstrated in patients undergoing aorto-iliac (n = 37) or femoro-crural graft reconstructions (n = 72); it was found in 41% and 35%, respectively (P < .001). In addition, a significantly increased frequency of APC resistance was found in patients who suffered from occlusion after reconstruction; 13 of 41 (32%) had the factor V Leiden gene mutation (P < .001), and 19 of 39 (49%) had an abnormal APC ratio (P < .001). Conclusion: The factor V Leiden gene mutation and abnormal APC ratios are significantly increased in patients with lower extremity peripheral vascular disease and failed reconstructions. An abnormal APC ratio was seen without factor V Leiden gene mutation in 37% of patients with peripheral vascular diseases, suggesting additional causes of an abnormal APC ratio, exclusive of gene mutation. (J Vasc Surg 1998;28:624-9.)     

Fluid overload and acute renal failure in pediatric stem cell transplant patients

Acute renal failure (ARF) with fluid overload (FO) occurs often in stem cell transplant (SCT) recipients. We have previously demonstrated that an increased percentage of FO prior to the initiation of continuous renal replacement therapy (CRRT) is associated with mortality in children with ARF. Based on these data, we devised a protocol for the prevention of FO in SCT patients with ARF. SCT patients with ARF and 5% FO were started on furosemide and low-dose dopamine. To allow for nutrition, medication, and blood product administration, RRT was initiated for patients with 10% FO. There were 272 patients who received allogeneic SCT from 1999 to 2002. Of these, medical records of 26 SCT patients with a first episode of oliguric ARF were reviewed. The mean patient age was 13±5 years (range 2–23.5 years). Mean days to ARF after SCT were 28±29 days (range 2–90 days). Of the 26 patients, 11 (42%) survived an initial ARF episode. All 11 survivors either maintained <10% FO during their course or re-attained <10% FO with RRT treatment. Of the 15 non-survivors, 6 had <10% FO at the time of death. Of 14 patients who received RRT, 4 (29%) survived. Mechanical ventilation and pediatric risk of mortality score 10 at the time of admission to the intensive care unit were associated with lower survival (P<0.05). The use of one or more pressors, the presence of graft-versus-host disease, and septic shock were not correlated with survival. Our data demonstrate that maintenance of euvolemia (<10% FO) is critical but not sufficient for survival in SCT patients with ARF, as all non-euvolemic patients died. We suggest that aggressive use of diuretics and early initiation of RRT to prevent worsening of FO may improve the survival of SCT patients.     

Outcome after steroid withdrawal in pediatric renal transplant patients receiving tacrolimus-based immunosuppression

BACKGROUND: Corticosteroids have always been an integral part of immunosuppressive regimens in renal transplantation. The primary goal of this analysis was to assess the safety of steroid withdrawal in our pediatric renal transplant recipients receiving tacrolimus-based immunosuppression. METHODS: Between December 1989 and December 1996, 82 renal transplantations were performed in pediatric patients receiving tacrolimus-based immunosuppression. Two of these patients lost their grafts within 3 weeks of transplantation (and were still on steroids at the time of graft loss), and were excluded from further analysis. Seventy-four patients (92.5%) were taken off prednisone a median of 5.7 months after transplantation. Of these 74, 56 (70%) remained off prednisone (OFF), and 18 (22.5%) were restarted on prednisone a median of 14.8 months after discontinuing steroids (OFF --> ON). 6(7.5%) were never taken off prednisone (ON). The mean follow-up was 59 +/- 23 months. RESULTS: The 1-, 3-, and 5-year actuarial patient survival rates in the OFF group were 100%, 98%, and 96%, respectively; in the OFF --> ON group, they were 100%, 100%, and 100%, and in the ON group, they were 100%, 83%, and 83%. The 1-, 3-, and 5- year actuarial graft survival rates in the OFF group were 100%, 95%, and 82%, respectively; in the OFF --> ON group, they were 100%, 89%, and 83%; and in the ON group, they were 100%, 50%, and 33%. Two of the six graft losses in the OFF group, three out of four in the OFF --> ON Group, and two out of five in the ON group, were to chronic rejection. A time-dependent Cox regression analysis showed that the hazard for graft failure for those who came and stayed off prednisone was 0.178 relative to those who were never withdrawn from prednisone (P=0.005). Patients who were 10 years of age or younger were withdrawn from prednisone earlier (median: 5 months) than those older than 10 years (median: 7.3 months, P=0.02). In addition, patients who never had acute rejection were withdrawn from steroids earlier (median: 5 months) than those who had one or more episodes of acute rejection (median: 7.6 months, P=0.001). There was no effect of donor age, race, sex, recipient race, sex, cadaveric versus living donor, 48-hr graft function, panel reactive antibody, and total HLA mismatches or matches on the likelihood of being weaned off steroids. Serum creatinine at most recent follow-up in the OFF group was 1.2 +/- 0.5 mg/dl; in the OFF --> ON group, it was 1.8 +/- 0.9 mg/dl, and in the ON group it was 2.0 mg/dl (P<0.003). The incidence of rejection in the OFF, OFF --> ON, and ON groups was 39%, 77%, and 100%, respectively (P<0.05). CONCLUSION: These data suggest that steroid withdrawal in pediatric renal transplant patients receiving tacrolimus-based immunosuppression is associated with reasonable short- and medium-term patient and graft survival, and acceptable renal function. Patients who discontinue and then resume steroids had patient and graft survival rates comparable with those in patients who discontinue and stay off steroids, but had a higher serum creatinine and a higher incidence of rejection.