Safety and efficacy of pravastatin therapy for the prevention of hyperlipidemia in pediatric and adolescent cardiac transplant recipients

Uncertain benefit of statins in pediatric heart transplant recipients: A PHTS analysis

BACKGROUND

Cardiac allograft vasculopathy (CAV) is a leading cause of graft failure in pediatric heart transplant recipients (HTRs). Early statin use has been shown to reduce CAV incidence and all-cause mortality in adult HTRs. We sought to evaluate the contemporary prevalence and trends of statin use in pediatric HTRs and the association between statin use with CAV development and graft failure.

METHODS

Patients aged <17 years at the time of primary heart transplant who survived to ≥3 years without CAV were identified from the Pediatric Heart Transplant Society database (2001-2018). Statin use in the first 3 years posttransplant was defined as consecutive, intermediate, or absent. Kaplan-Meier survival, multivariable modeling, and propensity score-matched analyses evaluated associations between statin use and CAV incidence and graft survival, with subanalyses performed on subjects aged ≥10 years at transplant.

RESULTS

Among 3,485 (of which 1,086 aged ≥10 years) HTRs, 584 (17%) received consecutive statin therapy, 647 (19%) received intermediate use, and 2,254 (65%) received no statin therapy. Statin use varied widely between sites, with increasing use in the ≥10-year-old cohort over time. By multivariate analysis, statin use was not associated with graft loss. Consecutive statin use was also not associated with graft survival or freedom from CAV development when compared to absent statin use in unmatched or propensity-matched analyses.

CONCLUSIONS

While statins remain commonly utilized in pediatric HTRs, early consecutive statin therapy did not decrease CAV incidence or graft loss. The differing effects of statins on CAV development and progression in pediatric vs adult HTRs suggest differing risk and mediating factors and require further study.

Statin Safety and Associated Adverse Events: A Scientific Statement From the American Heart Association

One in 4 Americans >40 years of age takes a statin to reduce the risk of myocardial infarction, ischemic stroke, and other complications of atherosclerotic disease. The most effective statins produce a mean reduction in low-density lipoprotein cholesterol of 55% to 60% at the maximum dosage, and 6 of the 7 marketed statins are available in generic form, which makes them affordable for most patients. Primarily using data from randomized controlled trials, supplemented with observational data where necessary, this scientific statement provides a comprehensive review of statin safety and tolerability. The review covers the general patient population, as well as demographic subgroups, including the elderly, children, pregnant women, East Asians, and patients with specific conditions such as chronic disease of the kidney and liver, human immunodeficiency viral infection, and organ transplants. The risk of statin-induced serious muscle injury, including rhabdomyolysis, is <0.1%, and the risk of serious hepatotoxicity is ≈0.001%. The risk of statin-induced newly diagnosed diabetes mellitus is ≈0.2% per year of treatment, depending on the underlying risk of diabetes mellitus in the population studied. In patients with cerebrovascular disease, statins possibly increase the risk of hemorrhagic stroke; however, they clearly produce a greater reduction in the risk of atherothrombotic stroke and thus total stroke, as well as other cardiovascular events. There is no convincing evidence for a causal relationship between statins and cancer, cataracts, cognitive dysfunction, peripheral neuropathy, erectile dysfunction, or tendonitis. In US clinical practices, roughly 10% of patients stop taking a statin because of subjective complaints, most commonly muscle symptoms without raised creatine kinase. In contrast, in randomized clinical trials, the difference in the incidence of muscle symptoms without significantly raised creatinine kinase in statin-treated compared with placebo-treated participants is <1%, and it is even smaller (0.1%) for patients who discontinued treatment because of such muscle symptoms. This suggests that muscle symptoms are usually not caused by pharmacological effects of the statin. Restarting statin therapy in these patients can be challenging, but it is important, especially in patients at high risk of cardiovascular events, for whom prevention of these events is a priority. Overall, in patients for whom statin treatment is recommended by current guidelines, the benefits greatly outweigh the risks.

Post-transplant dyslipidemia: Mechanisms, diagnosis and management

Post-transplant dyslipidemia is highly prevalent and presents unique management challenges to the clinician. The two major outcomes to consider with post-transplant therapies for dyslipidemia are preserving or improving allograft function, and reducing cardiovascular risk. Although there are other cardiovascular risk factors such as graft dysfunction, hypertension, and diabetes, attention to dyslipidemia is warranted because interventions for dyslipidemia have an impact on reducing cardiac events in clinical trials specific to the transplant population. Dyslipidemia is not synonymous with hyperlipidemia. Numerous mechanisms exist for the occurrence of post-transplant dyslipidemia, including those mediated by immunosuppressive drug therapy. Statin therapy has received the most attention in all solid organ transplant recipient populations, although the effect of proper dietary advice and adjuvant pharmacological and non-pharmacological agents should not be dismissed. At all stages of treatment appropriate monitoring strategies for side effects should be implemented so that the benefits from these therapies can be achieved. Clinicians have a choice when there is a conflict between various transplant society and lipid society guidelines for therapy and targets.

Variability in hepatic expression of organic anion transporter 7/SLC22A9, a novel pravastatin uptake transporter: impact of genetic and regulatory factors

Human organic anion transporter 7 (OAT7, SLC22A9) is a hepatic transport protein poorly characterized so far. We therefore sought to identify novel OAT7 substrates and factors contributing to variable hepatic OAT7 expression. Using OAT7-expressing cells, pravastatin was identified as a substrate. Hepatic SLC22A9/OAT7 mRNA and protein expression varied 28-fold and 15-fold, respectively, in 126 Caucasian liver samples. Twenty-four variants in SLC22A9 were genotyped, including three rare missense variants (rs377211288, rs61742518, rs146027075), which occurred only heterozygously. No variant significantly affected hepatic SLC22A9/OAT7 expression. The three missense variants, however, showed functional consequences when expressed in vitro. Hepatic nuclear factor 4-alpha (HNF4α) emerged as a major transcriptional regulator of SLC22A9 by a series of in silico and in vitro analyses. In conclusion, pravastatin is the first identified OAT7 drug substrate. Substantial inter-individual variability in hepatic OAT7 expression, majorly driven by HNF4α, may contribute to pravastatin drug disposition and might affect response.The Pharmacogenomics Journal advance online publication, 4 August 2015; doi:10.1038/tpj.2015.55.

Pediatric transplantation: opportunities for pharmacogenomics and genomics

Heterogeneity is the rule among pediatric heart transplant recipients. Patients vary in age, size, organ maturity, immune system maturity and underlying disease etiology, which can all influence post-transplant outcomes. Overall, the survival of pediatric transplant recipients continues to improve and the goal remains long-term survival of the primary graft and mitigation of long-term complications and adverse events. The evolving fields of pharmacogenomics and genomics have the potential to revolutionize and personalize the care of pediatric transplant recipients, and although clinical validation in a pediatric cohort is lacking, many of these technologies are becoming more readily available. We discuss genotype-guided dosing of immunosuppressant medications and other commonly used medications after transplantation, the influence of donor and recipient genotype on risk of post-transplant complications, genotype-guided selection of therapies to treat complications, and the use of next-generation sequencing for noninvasive detection of graft rejection.

Unusual pattern of dyslipidemia in children receiving steroid minimization immunosuppression after renal transplantation

BACKGROUND AND OBJECTIVES

Corticosteroids are an important contributor to posttransplant hyperlipidemia. Since 2004, we have used a steroid minimization immunosuppression protocol. This study investigated the effect of steroid minimization on dyslipidemia in pediatric renal allograft recipients.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Children (<18 years) who underwent renal transplants at our center from January 2001 to January 2008 were studied. Data analyzed included age, gender, race, body mass index, cholesterol, triglyceride, LDL cholesterol, HDL cholesterol, and steroid dose. Data between the cohorts receiving maintenance steroids and steroid-minimization were compared using multivariable analyses. The primary outcome measures were the prevalence of, and the effect of steroid use, on dyslipidemia.

RESULTS

Twenty-nine patients were studied. Sixteen were receiving maintenance steroids, and 13 were on a steroid minimization regimen. Mixed effects analysis of covariance models demonstrated that at 1 month, children receiving maintenance steroids had higher cholesterol compared with the steroid minimization group. Statistically significant differences in total cholesterol were not seen at other time points. Similar findings were noted for the LDL cholesterol, LDL/HDL, and cholesterol/HDL ratios. At 1 month, the serum HDL cholesterol was substantially lower in the steroid minimization group. Differences in the HDL cholesterol levels remained significant throughout the first year.

CONCLUSIONS

Steroid use is a significant independent risk factor for hypercholesterolemia during the first post-transplant month. The significance of lower HDL cholesterol among patients receiving steroid minimization needs further study and may be cause for concern.

Adverse effects of immunosuppression in pediatric solid organ transplantation

Solid organ transplantation is a life-saving treatment for end-stage organ failure in children. Immunosuppressant medications are used to prevent rejection of the organ transplant. However, these medications are associated with significant adverse effects that impact growth and development, quality of life (QOL), and sometimes long-term survival after transplantation. Adverse effects can differ between the immunosuppressants, but many result from the overall state of immunosuppression. Strategies to manage immunosuppressant adverse effects often involve minimizing exposure to the drugs while balancing the risk for rejection. Early recognition of immunosuppressant adverse effects may help to reduce morbidities associated with solid organ transplantation, improve QOL, and possibly increase overall patient survival.

Long-term outcomes after 1000 heart transplantations in six different eras of innovation in a single center

The objective of this study was to evaluate long-term outcomes of cardiac transplantation (HTx) in different eras of innovation at a single center during a period of 27 years. We performed a retrospective analysis of 960 cardiac allograft recipients (40 re-HTx) between 1981 and 2008. The results of six different eras based on milestones in HTx were analysed: Era 1: the early years (n = 222,1981-1992); era 2: introduction of inhalative nitric oxide, prostanoids, University of Wisconsin solution (UW) replacing Bretschneider's solution (HTK,n = 118, 1992-1994); era 3: statins (n = 102, 1994-1995); era 4: tacrolimus(n = 115, 1995-1996); era 5: mycophenolate mofetil (MMF, n = 143, 1997-2000) and era 6: sirolimus (n = 300, 2000-2008). Outcome variables weresurvival, freedom from cardiac allograft vasculopathy (CAV) and from acute rejection episodes (AREs). Differences in survival was found comparing era 1 and era 2 with era 4 and era 6 (P < 0.001). Organ preservation through UW demonstrated a significantly better survival as compared with HTK(P < 0.001). Less AREs occurred in patients receiving tacrolimus-sirolimus ortacrolimus-MMF (P < 0.001). Patients receiving tacrolimus-MMF showed less CAV than when treated with cyclosporine-MMF (P < 0.005). There were more ventricular assist device implantations and more re-HTx in era 6 (P < 0.0001)than when compared with other eras. Although the causes for improvement in survival over time are multifactorial, we believe that changes in immunosuppressive therapy have had a major impact on survival.

Prevention of pediatric graft coronary artery disease: atorvastatin

Graft coronary artery disease is a significant cause of late graft failure and death after cardiac transplantation. HMG-coenzyme A reductase inhibitors have been used safely in children but their preventative effects against GCAD are not well known. We investigated whether atorvastatin when initiated early could prevent against the development of pediatric GCAD. Pediatric patients (transplanted between October 28, 1992 and July 9, 2004) were stratified into two groups based on whether or not they received atorvastatin early after transplant. Angiograms were reviewed by a single observer blinded to the treatment strategies and clinical outcomes. Actuarial survival method and the Mantel-Cox test were used to assess statistical significance. Freedom from GCAD was higher among those treated with atorvastatin early in the post-transplant course. One, three, and five-yr freedom from GCAD was significantly greater in the early treatment group (97%, 93%, and 93% respectively) compared with the control group (72%, 65%, and 60% respectively, p < 0.005). The early treatment group was also noted for fewer rejection episodes in the first post-transplant year. The use of atorvastatin when initiated early in the post-transplant course appears protective against graft coronary artery disease.

Rational approach to the treatment for heterozygous familial hypercholesterolemia in childhood and adolescence: a review

Atherosclerosis represents a disease that begins in childhood and in which LDL cholesterol plays a pivotal role for the development of the pathology. Children and adolescents with high cholesterol levels are more likely than their peers to present cholesterol elevation as adults. The identification of genetic dyslipidemias associated with premature cardiovascular disease is crucial during childhood to delay or prevent the atherosclerotic process. Guidelines for the diagnosis and treatment of hypercholesterolemia during pediatric age are available from the National Cholesterol Education Program. A heart-healthy diet should begin at the age of 2 yr and a large number of studies have demonstrated no adverse effects on nutritional status, growth, pubertal development, and psychological aspects in children and adolescents limiting total and saturated fat intake. Pharmacotherapy should be considered in children over 10 yr of age when LDL cholesterol concentrations remain very high despite severe dietary therapy, especially when multiple risk factors are present. The only lipid-lowering drugs recommended up to now for childhood and adolescence are resins reported to be effective and well tolerated, although compliance is very poor because of unpalatability. The use of statins is increasing and seems to be effective and safe in children, even if studies enrolled a small number of patients and evaluated efficacy and safety for short-term periods. Recently, an interesting drug represented by ezetimibe has been found that may provide cholesterol-lowering additive to that reached with statin treatment. This review provides an update on recent advances in the diagnosis, therapy, and follow-up of familial hypercholesterolemia during pediatric age and adolescence.

Low HDL-C predicts the onset of transplant vasculopathy in pediatric cardiac recipients on pravastatin therapy

The levels and protein/lipid compositions of major lipoprotein particles of 19 pediatric cardiac transplant recipients (4-18 yr of age) were studied in this prospective, open clinical follow-up study before and at one yr of pravastatin therapy (10 mg/day). The recipients were grouped into those with (n = 6; group A) and those without (n = 13; group B) angiographically detectable vasculopathy. Twenty-one pediatric non-transplant controls were studied at baseline. At baseline, the group A recipients had 29% lower HDL-C concentrations (p = 0.031) and 29% higher apoB-100/apoA-I ratios (p = 0.034) than the group B recipients. At one yr of pravastatin, the respective figures were 29% (p = 0.013) and 33% (p = 0.005). Compared with the healthy pediatric controls, the transplant recipients had significantly higher serum TG before pravastatin [median (range): 1.3 mmol/L (0.6-3.2) vs. 0.7 mmol/L (0.3-2.4), p = 0.0002] and at one yr [1.3 mmol/L (0.5-3.5) vs. 0.7 mmol/L (0.3-2.4), p = 0.0004]. The baseline apoB-100/apoA1 ratios of the recipients were 33% higher (p = 0.005). In conclusion, low HDL-C and high apoB-100/apoA-I ratio were associated with angiographically detectable vasculopathy. Even though pravastatin effectively lowered the TC and LDL-C and improved compositional properties of LDL and HDL(2) particles, it failed to normalize the elevated TG and, in some patients, to prevent the progression of transplant vasculopathy.

The use of statins in pediatrics: knowledge base, limitations, and future directions

The 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors, or statins, effectively reduce coronary morbidity and mortality in high-risk adults. They are also some of the most widely prescribed medications in the United States. Their use in pediatrics, however, remains circumscribed. In this article we review the cholesterol hypothesis and focus on the knowledge base of the use of statins in adults and children. We pay particular attention to the known effects of statins in primary and secondary prevention of cardiovascular events. The toxicities of statins and their limitations in pediatrics are then considered. The use of statins in conjunction with noninvasive modalities of assessing atherosclerotic burden are also reviewed. Finally, we suggest methods to advance the use of statins in childhood that introduce their potential benefits to those individuals at highest risk for future events.

Pharmacokinetics and response to pravastatin in paediatric patients with familial hypercholesterolaemia and in paediatric cardiac transplant recipients in relation to polymorphisms of the SLCO1B1 and ABCB1 genes

AIMS

Our aim was to investigate associations between the single nucleotide polymorphisms (SNPs) in the SLCO1B1 (encoding OATP1B1) and ABCB1 (encoding P-glycoprotein) genes with the pharmacokinetics and efficacy of pravastatin in children with heterozygous familial hypercholesterolaemia (HeFH) and in paediatric cardiac transplant recipients.

METHODS

Twenty children with HeFH (aged 4.9-15.6 years) and 12 cardiac transplant recipients (aged 4.4-18.7 years and receiving triple immunosuppressive medication) who had participated in previous pharmacokinetic and pharmacodynamic studies with pravastatin were genotyped for the -11187G > A and 521T > C SNPs in the SLCO1B1 gene and for the 2677G > T/A and 3435C > T SNPs in the ABCB1 gene.

RESULTS

Two HeFH patients with the -11187GA genotype had a 81% lower peak plasma pravastatin concentration (Cmax) (difference in means -13.9 ng ml(-1), 95% CI -21.1, -6.7; P < 0.001) and a 74% smaller area under the plasma concentration-time curve (AUC0, infinity) (-25.3 ng ml(-1) h, 95% CI -35.6, -15.0; P < 0.0001) and significantly greater increase in high density lipoprotein (HDL) cholesterol after 2 months treatment with pravastatin than patients with the reference genotype. No significant differences were seen in the pharmacokinetics or effects of pravastatin between HeFH patients with the SLCO1B1 521TC and 521TT genotypes. The cardiac transplant recipients with the SLCO1B1 521TC genotype (n = 3) had a 46% lower Cmax (-67.7 ng ml(-1), 95% CI -135.7, 0.3; P = 0.055) and 62% lower AUC(0,24 h) (-228.5 ng ml(-1) h, 95% CI -402.7, -54.3; P = 0.016) and a shorter half-life (t1/2) (0.9 +/- 0.1 vs. 1.3 +/- 0.4 h, P = 0.015) of pravastatin than those with the reference genotype. Decreases in total and low-density lipoprotein cholesterol by pravastatin were significantly smaller, and the increase in HDL-cholesterol was greater in the transplant recipients with the 521TC genotype compared with patients with the 521TT reference genotype.

CONCLUSIONS

In children with HeFH and in paediatric cardiac transplant recipients receiving immunosuppressive medication, the -11187G > A and SLCO1B1 521T > C SNPs were associated with decreased plasma concentrations of pravastatin. These differences are opposite to those seen previously in healthy adults. The mechanisms underlying these phenomena are unclear and warrant further study.

Advances in pediatric heart transplantation

PURPOSE OF REVIEW

Heart transplantation has become a reasonable treatment option for pediatric patients with end-stage heart failure or complex congenital cardiac defects not amenable to conventional surgical intervention. This review will summarize the current state of pediatric cardiac transplantation and review recent advances leading to new therapies.

RECENT FINDINGS

Improvements in early mortality after cardiac transplantation have occurred consistently over time since the 1980s, short-term survival rates are high, and most patients enjoy an excellent quality of life with minimal restrictions. The reduction of late mortality is still a major challenge, however, largely as a result of transplant-related coronary artery disease causing chronic graft failure and arrhythmogenic sudden death. Additional causes of morbidity and mortality occurring late after transplantation include renal dysfunction related to chronic immunosuppressive therapy with calcineurin inhibitors (tacrolimus or cyclosporine) and posttransplant lymphoproliferative disorders related to chronic immunosuppression. Newer agents (sirolimus, everolimus) have shown promise in immunosuppressive regimens that may alter the development or progression of long-term complications.

SUMMARY

New immunosuppressive agents allow alterations in drug regimens to minimize renal complications, and may influence the incidence and progression of transplant vasculopathy. Recent studies on posttransplant lymphoproliferative disorders should result in earlier diagnosis and therapy.

Pharmacotherapy of hyperlipidemia in pediatric heart transplant recipients: current practice and future directions

Lipoprotein abnormalities are fairly common after pediatric heart transplantation. Graft coronary artery disease (GCAD) limits long-term survival and has been linked to elevated serum triglyceride levels and decreased high-density lipoprotein levels. Histologically, GCAD represents intimal hyperplasia of the coronary vessel and is best imaged by intravascular ultrasound.A number of pharmacologic agents are available for the management of lipid disorders but experience with these drugs has mainly been in adults. HMG-CoA reductase inhibitors (statins) are currently used by many adult transplantation centers to alter lipid profiles in the hope of reducing GCAD. The use of statins among pediatric heart transplant centers is more limited. Although rhabdomyolysis is a concern with these agents, the incidence among individuals receiving immunosuppressant therapy is low. Aside from their lipid-lowering properties, statins may also protect against graft failure and rejection.

Prospective monitoring of lipid profiles in children receiving pravastatin preemptively after renal transplantation

Hyperlipidemia is common after renal transplantation (Tx) and contributes to the increased cardiovascular morbidity seen in the post-transplant period. Limited data are available on the utility of the statins in children after renal Tx. This 12-month prospective study was undertaken to determine the efficacy of pravastatin in reducing dyslipidemia after renal Tx in children and to determine predictors of dyslipidemia after Tx. From August 2001 to April 2004, all 17 newly transplanted pediatric renal transplant recipients at our center were preemptively treated with pravastatin from the immediate post-transplant period. Fasting lipid profiles were obtained at 1, 3, 6 and 12 months after Tx. Trends in the lipid profile were analyzed using the repeated measures general linear model (GLM). A historical cohort of pediatric renal-transplant recipients not treated with pravastatin was used as the control population. The mixed effects GLM was used for multivariable logistic regression analyses to determine the independent effect of age, pretransplant cholesterol (Chol), body mass index (BMI), creatinine clearance (CrCl), and corticosteroid and tacrolimus doses on the development of dyslipidemia. The mean age of the children at Tx was 8.7 yr. The GLM analysis showed that with time, there was a significant decline in the total Chol, serum triglyceride (TG), LDL and also HDL-Chol (p-value <0.05 for each). Compared with the controls, the mean serum Chol was lower at all time points post-transplant in the treated patients. However, despite treatment, the prevalence of hypercholesterolemia increased from 31% pretransplant to 53% at 1-month, but declined thereafter to 6% at 3 and 6 months and 0% at 1 yr. Multivariable regression analyses showed the prednisone dose, pretransplant Chol and age to be the most important risk factors for the development of dyslipidemia. No child developed complications related to therapy. In summary, pravastatin is safe in the post-transplant period in children and reduces serum Chol, LDL-Chol and TG. An unexpected finding in our study was the decline in HDL-Chol after Tx. Whether the preemptive use of the statins will result in lower cardiovascular morbidity, especially considering the concomitant reduction in HDL-Chol remains to be determined.

Combined therapy with atorvastatin and calcineurin inhibitors: no interactions with tacrolimus

Increased systemic exposure to statins and consequent risk for complications has been reported in patients concomitantly treated with cyclosporin A (CsA). This has been ascribed to inhibition of drug catabolism by cytochrome P450 3A4 (CYP3A4) or drug transport by P-glycoprotein (PGP) and organic anion transporting polypeptide (OATP1B1). It is not known whether the combination of statins and tacrolimus (Tac) also suffers from this drawback. Therefore, a pharmacokinetic study of atorvastatin and its metabolites was performed in 13 healthy volunteers after 4 days' treatment, and after short (12 h) concomitant exposure to CsA and Tac. A complementary assessment of overall CYP, and hepatic and intestinal CYP3A4+PGP activity was performed after each treatment episode and compared to baseline (no drugs). Systemic exposure to atorvastatin acid and its metabolites was significantly increased when administered with CsA. In contrast, intake of Tac did not have any impact on atorvastatin pharmacokinetics. Concomitantly, a profound decrease of hepatic and intestinal PGP and an increase of intestinal CYP3A4 were noted with CsA, whereas no effect was seen after atorvastatin therapy with or without Tac. Based on these findings treatment with Tac appears a safer option for patients needing a combination of statins and calcineurin inhibitors.

Pravastatin therapy is associated with reduction in coronary allograft vasculopathy in pediatric heart transplantation

BACKGROUND

Hydroxymethylglutaryl CoA reductase inhibitors (statins) have been demonstrated to reduce the risk of developing coronary allograft vasculopathy (CAV) following heart transplantation in adults and are used routinely in many centers. CAV and lipid abnormalities have been reported to be less prevalent in pediatric heart transplant recipients. It is not known whether statins reduce the risk of CAV in this population

METHODS

A retrospective review was performed to analyze the risk factors for developing CAV following pediatric heart transplantation with particular attention to the impact of pravastatin therapy. The study population was comprised of 129 pediatric patients who underwent 142 heart transplants at our institution from 1988 to 2003. The outcome variable was freedom from CAV, CAV being determined by coronary angiography or autopsy.

RESULTS

CAV was identified in 25 recipients at a median of 3.7 years after transplantation. There were 331 patient-years of pravastatin therapy. Pravastatin therapy resulted in a reduction in total cholesterol levels, 162 +/- 29 to 137 +/- 20 mg/dl, p = 0.01. In multivariate analysis the use of pravastatin was associated with a lower incidence of CAV (p = 0.03), whereas an increased frequency of late rejection (p = 0.003) and earlier year of transplantation (p = 0.04) were associated with increased risk of CAV.

CONCLUSIONS

The routine use of pravastatin was associated with a lower risk following pediatric heart transplantation. Further studies into the relationship between lipid abnormalities, inflammation and rejection, and the development of CAV in children are warranted.

Cardiac Transplantation in Pediatric Patients: Fifteen-Year Experience of a Single Center

BACKGROUND

Pediatric heart transplantation is a surgical therapy for dilated cardiomyopathy and for complex congenital heart defects with low pulmonary artery resistance. However, it is still discussed as controversial because of uncertain long-term results. We report our experience with pediatric heart transplantation in a heterogeneous population.

METHODS

Since 1988, 50 heart transplants were performed in 47 patients (30 with dilated cardiomyopathy, 17 with congenital heart disease). Mean age was 9.4 +/- 6.9 years (range, 4 days to 17.9 years). Twenty-three patients had a total of 36 previous operations. Clinical outcome was evaluated retrospectively.

RESULTS

Perioperative mortality was 6% due to primary graft failure. Late mortality (12%) was caused by acute rejection (n = 2), pneumonia (n = 2), intracranial hemorrhage (n = 1), and suicide (n = 1). Mean follow-up was 5.24 +/- 3.6 years. Actuarial 1, 5, and 10 year survival was 86%, 86%, and 80% and improved significantly after 1995 (92% [1 year]; 92% [5 years]). There was no significant difference between patients with dilated or congenital heart disease (1 year: 86% vs 82%; 5 years: 83% vs 74%; 10 years 83% vs 74%; p = 0.62). Three patients with therapy resistant acute or chronic rejection and assisted circulation underwent retransplantation and are alive. Freedom from acute rejection after 5 years was 40% with primary cyclosporine immunosuppression regime and 56% with tacrolimus. Since the introduction of mycophenolate mofetil, freedom from acute rejection increased to 62%. All survivors are at home and in good cardiac condition.

CONCLUSIONS

Pediatric heart transplantation is the treatment of choice for end-stage dilated cardiomyopathy as for congenital heart disease with excellent clinical midterm results. It is a valid alternative to reconstructive surgery in borderline patients. However, further follow-up is necessary to evaluate the long-term side effects of immunosuppressants.

Dyslipoproteinemia and premature atherosclerosis in pediatric systemic lupus erythematosus

While modern treatments for systemic lupus erythematosus (SLE) have resulted in greatly improved long term outcome in children and adults, complications of atherosclerosis have become a major cause of morbidity and mortality. Although children and adolescents with SLE rarely experience adverse cardiovascular events before adulthood, dyslipoproteinemia and early evidence of premature atherosclerosis is present much earlier. Accelerated atherogenesis in SLE is multifactorial, most likely reflecting vascular, immune, and inflammatory changes along with medication effects. The long term complications of cardiovascular disease in childhood lupus present a particularly important target for intervention because of the potential return on investment by significantly lengthening life and improving quality of life over many decades. An ongoing multi-center, randomized, controlled trial, Atherosclerosis Prevention in Pediatric Lupus Erythematosus (APPLE), testing the efficacy of statins in preventing premature atherosclerosis in children and adolescents with SLE will guide future therapeutic intervention.

Hypercholesterolemia is common after pediatric heart transplantation: initial experience with pravastatin

BACKGROUND

Coronary allograft vasculopathy (CAV) is a progressive complication after cardiac transplantation and limits survival. Hyperlipidemia is a known risk factor for CAV, and pravastatin is effective in decreasing cholesterol levels in adults after transplantation. However, few data exist regarding lipid profiles and statin use after pediatric heart transplantation. We evaluated the prevalence of hyperlipidemia in pediatric heart transplant recipients and assessed the efficacy and safety of pravastatin therapy.

METHODS

We performed a retrospective chart review of lipid profiles > or =1 year after surgery in 50 pediatric cardiac transplant recipients to assess the incidence of hyperlipidemia. Twenty of these patients received pravastatin for hypercholesterolemia. Their primary immunosuppression therapy was cyclosporine/prednisone plus either azathioprine or mycophenolate mofetil. We reviewed serial lipid profiles, creatinine phosphokinase, and liver enzymes.

RESULTS

Overall, 36% of the patients (n = 50) had total cholesterol (TC) concentrations > 200 mg/dl and 52% had low-density lipoprotein (LDL) >110 mg/dL beyond 1 year after transplantation. Of the 20 treated with pravastatin, TC (236 +/- 51 vs 174 +/- 33 mg/dl) and LDL levels (151 +/- 32 vs 99 +/- 21 mg/dl) decreased significantly with therapy (p <.0001). We found no symptoms; however, 1 patient had increased creatinine phosphokinase. Liver enzyme concentrations remained normal in all.

CONCLUSIONS

Hypercholesterolemia is prevalent in pediatric cardiac transplant recipients. Pravastatin therapy is effective in decreasing TC and LDL levels, seems to be safe, and is tolerated well. Further studies are necessary to determine whether pravastatin treatment is beneficial in decreasing CAV.

Pilot study describing the use of pravastatin in pediatric renal transplant recipients

Renal transplant (Tx) recipients frequently develop hypercholesterolemia. Pravastatin (P) has been shown to be effective in adult renal Tx recipients, not only in reducing serum cholesterol, but possibly also in decreasing graft rejection. However, there are no data on the use of P in children following renal transplantation. We conducted a retrospective case-control study evaluating the safety and efficacy of P (10-20 mg/day) in reducing hypercholesterolemia, when used pre-emptively in the post-Tx period in seven children, compared with an historical control (C) group of nine children who had not received P. The two groups were comparable with respect to their demographics and in their pretransplant serum cholesterol. Compared with the C group, the mean serum cholesterol in the P group was lower at 3 months (159 mg/dL vs. 225 mg/dL), 6 months (134 mg/dL vs. 200 mg/dL), 9 months (134 mg/dL vs. 209 mg/dL), and 12 months (125 mg/dL vs. 195 mg/dL) (p < 0.005 for all, Student's two-tailed t-test). At 1 month only 43% of the P group had hypercholesterolemia compared with 67% of the controls; by 12 months this difference was even more significant (0% in the P group vs. 45% in the C group). None of the treated patients developed any adverse reactions. This study demonstrates that the pre-emptive use of P in pediatric renal Tx recipients appears to be effective in significantly reducing serum cholesterol. Whether this effect will translate into improved allograft and patient survival in the long term cannot be predicted at present and will require additional studies to evaluate.

Cardiomyocyte injury to transplant: pediatric management

Cardiomyocyte injury in pediatric patients has a vast number of causes, which are often distinct from the causes of adult heart failure. However, the management of pediatric heart failure and heart transplantation has generally been inferred from adult studies. New therapies show great promise for the neurohormonal regulation of heart failure and the ability to control immunosuppression after heart transplantation. Large, randomized, multicenter, controlled clinical trials are needed to determine the efficacy of these therapies in this population. This article reviews the current recommendations and evidence-based medicine, where available, for the medical management of myopathic dysfunction and transplantation in pediatric patients.

Atorvastatin treatment for hyperlipidemia in pediatric renal transplant recipients

The objective of this prospective study was to determine the prevalence of hyperlipidemia in our pediatric renal transplant patients and to treat those with persistently elevated cholesterol and/or low-density lipoprotein (LDL) levels. All patients with a functioning renal allograft for greater than 6 months were studied (n = 18). Patients with cholesterol and/or LDL levels greater than the 95th percentile (n = 9) were commenced on an HMG-CoA reductase inhibitor, Atorvastatin and monitoring was performed for efficacy and adverse effects. Total serum cholesterol was elevated in 11 of 18 (61%) and triglyceride (TG) was elevated in 12 of 18 (67%) patients. Atorvastatin treatment was effective with a mean percentage reduction of total cholesterol of 41 +/- 10% (p < 0.01 vs. before treatment), LDL 57 +/- 7% (p < 0.01 vs. before treatment) and TG 44 +/-25% (p = 0.05 vs. before treatment). No adverse effects on allograft function or cyclosporin levels were experienced. Hyperlipidemia is a common problem and Atorvastatin is a safe and effective treatment in pediatric renal transplant recipients.

Drug interactions with tacrolimus

Tacrolimus is a drug for which therapeutic drug monitoring is recommended. The existence of a wide variety of potential drug interactions further supports the current strategy of measuring whole blood tacrolimus concentrations in transplanted patients. Cytochrome P450 (CYP)3A, the major phase I metabolising enzyme in humans, and the multi-drug efflux pump, P-glycoprotein, are present at high levels in the villus tip of enterocytes in the gastrointestinal tract. Oral bioavailability of tacrolimus can be increased by concomitant administration of inhibitors of either CYP3A or P-glycoprotein. CYP activity in the liver also influences tacrolimus concentrations. As a result, several drugs that are frequently being used in transplantation, such as corticosteroids and antifungal agents, will affect tacrolimus concentrations. Knowledge of such drug interactions is extremely important, as they may lead to clinically important under- or overexposure to tacrolimus, with acute rejection episodes or serious toxicity as a result.

Efficacy and safety of atorvastatin after pediatric heart transplantation

BACKGROUND

Lipid abnormalities are prevalent after pediatric and adult heart transplantation. 3-Hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors are efficacious and safe and can lower the incidence of graft coronary artery disease after heart transplantation in adults. Given the high prevalence of lipid abnormalities and the increased recognition of graft coronary disease in children, we retrospectively investigated the efficacy and safety of atorvastatin among pediatric heart transplant recipients.

METHODS

Thirty-eight patients were started on atorvastatin 48.2 +/- 54.4 months after transplantation. Atorvastatin dosage was 0.2 +/- 0.1 mg/kg per day. No patient had changes in drug dose unless there was evidence for rhabdomyolysis, myositis or an asymptomatic rise in creatine kinase above normal. Laboratory studies included total cholesterol, triglycerides; high, low and very low-density lipoproteins (HDL, LDL and VLDL, respectively); creatine kinase; creatine; and serum alanine transaminase.

RESULTS

Significant declines in total cholesterol (20%), triglyceride (18%) and LDL (26%) were observed after starting atorvastatin therapy. There were no significant changes in HDL or VLDL compared with baseline. There were also no differences in alanine transaminase pre- vs post-atorvastatin therapy. Complications included muscle pain (n = 2) and asymptomatic elevations in creatine kinase (n = 2). Two of these 4 patients developed rhabdomyolysis. Excluding these 4 patients, creatine kinase did not rise compared with baseline. No patient developed alterations in renal function.

CONCLUSIONS

Use of atorvastatin in pediatric heart transplant recipients is effective in lowering total cholesterol, triglyceride and LDL without altering HDL levels. Complications included rhabdomyolysis, seen in 5%. Baseline and routine screening of creatine kinase should be employed in all pediatric patients undergoing HMG-CoA reductase inhibitor therapy.

Dyslipidemia in pediatric renal disease: epidemiology, pathophysiology, and management

Dyslipidemia increases the risk of cardiovascular events among individuals with renal disease, and there is a growing body of evidence that it hastens the progression of renal disease itself. Children with nephrotic syndrome or renal transplants have easily recognized hyperlipidemia. Among those with chronic renal insufficiency or end-stage renal disease, detection of dyslipidemia requires more careful analysis and knowledge of normal pediatric ranges. Disordered lipoprotein metabolism results from complex interactions among many factors, including the primary disease process, use of medications such as corticosteroids, the presence of malnutrition or obesity, and diet. The systematic treatment of dyslipidemia in children with chronic renal disease is controversial because conclusive data regarding the risks and benefits are lacking. Hepatic 3-methylglutaryl coenzyme A reductase inhibitors (statins), fibrates, plant stanols, bile acid-binding resins, and dietary manipulation are options for individualized treatment. Prospective investigations are required to guide clinical management.