Efficacy and safety of atorvastatin after pediatric heart transplantation

Cardiac allograft vasculopathy and survival in pediatric heart transplant recipients transitioned to adult care

BACKGROUND

Cardiac allograft vasculopathy (CAV) is an important cause of mortality after pediatric heart transplantation (HT) but there is a paucity of data regarding its incidence and impact on survival in pediatric recipients transitioned to adult care.

METHODS

We conducted a retrospective review of consecutive pediatric HT patients from 1989 to 2017 at the Hospital for Sick Children who transitioned to adult care at ≥18 years at Toronto General Hospital. We evaluated the incidence of International Society of Heart and Lung Transplantation CAV grade ≥1 using competing risk models. We assessed the association between all-cause mortality and CAV using Cox proportional hazards and used Kaplan Meier methods to evaluate all-cause mortality stratified by CAV and transplant era (1989-2001, 2002-2017).

RESULTS

Ninety-six patients were transitioned to adult care by January 2022, of which 53 underwent repeat coronary angiography as adults. CAV was newly diagnosed in 49% patients after transition to adult care. The overall incidence of CAV was 3.9 cases per 100 person-years. There was no difference in the adjusted incidence of CAV according to transplant era (subdistribution hazard ratios = 1.17, 95% confidence interval (CI) 0.54-2.66). CAV was associated with a higher risk of death in the early era (hazard ratio (HR) 10.29, 95% CI 2.16-49.96), but not in the recent era (HR 1.61, 95% 0.35-7.47).

CONCLUSIONS

There is a role for continued CAV surveillance after the transition to adult care. The implications of diagnosing CAV after the transition to adult care require further study, particularly because the risk of death in pediatric HT recipients diagnosed with CAV in the more recent era may be attenuated compared to the earlier HT era.

Cardiac allograft vasculopathy: A review

BACKGROUND

Heart transplantation has become the standard of care for pediatric patients with end-stage heart disease, and outcomes have consistently improved over the last few decades. CAV, however, remains a leading cause of morbidity and mortality in heart transplantation and is the leading cause of death beyond 3 years post-transplantation. We sought out to provide an in-depth overview of CAV in the pediatric heart transplant population.

METHODS

Database searches were conducted in both Medline and Embase on the topic of cardiac vasculopathy in pediatric heart transplant recipients. The search used five broad concept terms: heart transplant; pediatric; CAV; diagnosis, prognosis, and risk factors; and guidelines and reviews. References were captured if there was at least one term in each of the concepts. The search was limited to articles in the English language.

RESULTS

A total of 148 articles were identified via the literature search with further articles identified via review of references. Pediatric data regarding the etiology and development of CAV remain limited although knowledge about the immune and non-immune factors playing a role are increasing. CAV continues to be difficult to detect with many invasive and non-invasive methods available, yet their effectiveness in the detection of CAV remains suboptimal. There remains no proven medical intervention to treat or reverse established CAV disease, and CAV is associated with high rates of graft loss once detected. However, several medications are used in hopes of preventing, slowing progression, or modifying the outcomes.

CONCLUSION

This review provides a comprehensive overview of CAV, discusses its clinical presentation, risk factors, diagnostic tools used to identify CAV in the pediatric population, and highlights the current therapeutic options and the need for ongoing research.

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.

Pediatric heart transplantation: long-term outcomes

Pediatric heart transplant has become the standard of care for end-stage heart disease in children throughout the world. The number of transplants has grown dramatically since the first transplant was performed, and over the last two decades, outcomes have consistently improved with progression in knowledge enhancing the clinical course and outcomes of these patients. Short-term outcomes in the most recent era have been excellent resulting in a renewed focus towards medium- and long-term outcomes. This article will review the most up-to-date literature on overall heart transplantation outcomes and specific long-term outcomes including rejection, cardiac allograft vasculopathy, graft failure, infection, renal dysfunction, malignancy, and the need for re-transplantation. The article also explores the post-transplantation outcomes of special populations, including Fontan patients, ABO-incompatible recipients, sensitized recipients, extracorporeal membrane oxygenation, and ventricular assist devices. The article concludes with a look at transition from pediatric to adult care and medication adherence, which are becoming major issues related to long-term outcomes as post-transplant survival increases.

Treatment of Relapsed Chronic Subdural Hematoma in Four Young Children with Atorvastatin and Low-dose Dexamethasone

Chronic subdural hematoma (CSDH) can develop in children in rare cases. Burr-hole drainage (BHD) is the treatment of choice, but it is associated with a high rate of recurrence. This report describes four cases of pediatric patients (1-7 yrs of age) with post-BHD relapsed CSDH who were successfully treated with a drug regimen that included 2.5-5 mg atorvastatin daily combined with dexamethasone with stepwise-decreasing dosing for a total of 4 weeks. After 4 weeks of treatment, the hematoma was completely resolved in three patients and significantly reduced in one patient. During the treatment, no patient reported clinically significant adverse events. No patient experienced hematoma relapse during the follow-up period that lasted for up to 4 years. This case report suggests the need for a randomized placebo-controlled trial to evaluate this drug regimen for nonsurgical treatment of patients with relapsed CSDH.

Current state of pediatric cardiac transplantation

Pediatric heart transplantation is standard of care for children with end-stage heart failure. The diverse age range, diagnoses, and practice variations continue to challenge the development of evidence-based practices and new technologies. Outcomes in the most recent era are excellent, especially with the more widespread use of ventricular assist devices (VADs). Waitlist mortality remains high and knowledge of risk factors for death while waiting and following transplantation contributes to decision-making around transplant candidacy and timing of listing. The biggest gap impacting both waitlist and overall survival remains mechanical support options for infants and patients with single ventricle physiology. Though acute rejection has decreased progressively, both diagnosis and management of antibody-mediated rejection has become increasingly challenging and complex, as has the ability to understand the implication of anti-HLA antibodies detected both pre- and post-transplantation-including when and how to intervene. Trends in immunosuppression protocols include more use of induction therapy and steroid avoidance or withdrawal protocols. Common long-term morbidities include renal insufficiency, which can be mitigated with surveillance and renal-sparing strategies, and infections. Functional outcomes are excellent, but significant psychosocial challenges exist in relation to neurodevelopment, non-adherence, and transition from child-centered to adult-centered care. Cardiac allograft vasculopathy (CAV) remains a barrier to long-term survival, though it is more apparent that objective evidence of an impact on the allograft is important with regards to impact on outcomes. Retransplantation is rare in pediatric heart transplant recipients. Pediatric heart transplantation continues to evolve in order to address the challenges of the diverse group of patients that reach end-stage heart failure during childhood.

Modeling the effects of commonly used drugs on human metabolism

Metabolism contributes significantly to the pharmacokinetics and pharmacodynamics of a drug. In addition, diet and genetics have a profound effect on cellular metabolism with respect to both health and disease. In the present study, we assembled a comprehensive, literature-based drug metabolic reconstruction of the 18 most highly prescribed drug groups, including statins, anti-hypertensives, immunosuppressants and analgesics. This reconstruction captures in detail our current understanding of their absorption, intracellular distribution, metabolism and elimination. We combined this drug module with the most comprehensive reconstruction of human metabolism, Recon 2, yielding Recon2_DM1796, which accounts for 2803 metabolites and 8161 reactions. By defining 50 specific drug objectives that captured the overall drug metabolism of these compounds, we investigated the effects of dietary composition and inherited metabolic disorders on drug metabolism and drug-drug interactions. Our main findings include: (a) a shift in dietary patterns significantly affects statins and acetaminophen metabolism; (b) disturbed statin metabolism contributes to the clinical phenotype of mitochondrial energy disorders; and (c) the interaction between statins and cyclosporine can be explained by several common metabolic and transport pathways other than the previously established CYP3A4 connection. This work holds the potential for studying adverse drug reactions and designing patient-specific therapies.

Statin use in Australian children: a retrospective audit of four pediatric hospitals

AIM

The aim of this study was to perform an audit of the use of statins in Australian pediatric hospitals.

METHODS

A retrospective audit of patients prescribed statins during a visit to a pediatric hospital, as in- or outpatients, was performed in four major children's hospitals in three Australian states. Patients were identified through hospital pharmacy dispensing records. Statin use (dose, type) as well as medical history was recorded.

RESULTS

A total of 157 patients under the age of 18 were included in the audit. The most common reasons for being prescribed a statin included history of organ transplantation, renal disease and familial hypercholesterolemia (FH). Four statins were prescribed: atorvastatin (n = 77), pravastatin (n = 45), simvastatin (n = 25) and rosuvastatin (n = 10). All statins, apart from rosuvastatin, were used in very young children (1-7 years old). Polypharmacy was common in these patients, including combinations with calcineurin inhibitors and diltiazem, which can increase systemic statin exposure. A small number of very young children were prescribed high doses of statin, based on mg/kg dosing.

CONCLUSIONS

Statins were prescribed to children younger than suggested by current Australian guidelines, with atorvastatin being the preferred statin of choice. Long-term safety studies on the use of statins in children have only included FH patients so far, who are generally healthy besides their raised lipid levels. Further long-term safety studies are needed to include the more vulnerable transplant and renal patients, identified in this audit as being prescribed statins. This can help formulate guidelines for the safest possible use of this class of drugs in the pediatric setting, including the possibility of weight-based recommendations for younger children.

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.

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.

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.

Drug therapy of high-risk lipid abnormalities in children and adolescents: a scientific statement from the American Heart Association Atherosclerosis, Hypertension, and Obesity in Youth Committee, Council of Cardiovascular Disease in the Young, with the Council on Cardiovascular Nursing

Despite compliance with lifestyle recommendations, some children and adolescents with high-risk hyperlipidemia will require lipid-lowering drug therapy, particularly those with familial hypercholesterolemia. The purpose of this statement is to examine new evidence on the association of lipid abnormalities with early atherosclerosis, discuss challenges with previous guidelines, and highlight results of clinical trials with statin therapy in children and adolescents with familial hypercholesterolemia or severe hypercholesterolemia. Recommendations are provided to guide decision-making with regard to patient selection, initiation, monitoring, and maintenance of drug therapy.

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.

Pediatric cardiac transplantation

Pediatric heart transplantation has undergone major changes over the past two decades, marked by a substantial improvement in survival, reduction in posttransplant complications, and enhancement in quality of life for transplant recipients. Actuarial survival has improved substantially in the last decade. Indications for pediatric heart transplant have changed as surgery for complex congenital heart lesions has evolved. There are now left and right ventricular assist devices that are suitable for use in infants as a bridge to transplantation. New immunosuppressive agents have reduced the risk of rejection while minimizing side effects and strategies to reduce the risk of graft coronary disease are beginning to show promise. Finally, true long-term survival for children after heart transplant has now been demonstrated and quality of life is excellent.

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.

Effect of age on lipid profiles in pediatric heart transplant recipients

This study's objectives were to determine if pediatric orthotopic heart transplant (OHT) recipients over all ages develop hyperlipidemia and, secondarily, to identify the effects of immunosuppressive agents and statins on lipid profiles in these patients. Retrospective chart review was performed for pediatric patients transplanted between January 1987 and June 2002. Of the 100 OHTs performed, 50 patients satisfied the inclusion criteria and were grouped by age at OHT as follows: group 1 (n = 16): 0-4 yr; group 2 (n = 10): 5-9 yr; group 3 (n = 15): 10-14 yr; group 4 (n = 9): 15-18 yr. There were 2789 lipid levels recorded, and each patient had an average of 14 post-OHT lipoprotein panels measured. Post-OHT total cholesterol and low-density lipoprotein (LDL) levels were significantly greater than those of the general population for the entire follow-up period in all age groups, except for LDL levels in group 2. Cyclosporin level and prednisone dose were positively associated with total cholesterol and LDL levels (p < 0.03). Statins significantly decreased total cholesterol and LDL levels (p < 0.001). Hyperlipidemia affects OHT patients of all ages. Even the youngest patients may benefit from immunosuppression using an alternative to cyclosporin, such as tacrolimus, and steroid-free regimens, which may improve lipid profiles. Once safety and efficacy data are available, all age groups may benefit from statins.

Experience of Percutaneous Coronary Intervention in the Management of Pediatric Cardiac Allograft Vasculopathy

In a retrospective study, we examined the procedural success rate and the short-, intermediate-, and long-term outcomes of coronary interventional procedures in children with cardiac allograft vasculopathy. Seven patients underwent 13 interventional procedures: balloon angioplasty alone (n = 3), angioplasty with stenting (n = 9), or angioplasty with brachytherapy (n = 1), with procedural success in all. Two major complications (cardiac arrest) and a single death occurred in the immediate postprocedural period. Five (83%) of the remaining 6 patients developed moderate to severe restenosis, diffuse disease, or progressive vasculopathy; 3 have been retransplanted, 1 died from progressive cardiac allograft vasculopathy, and 1 is awaiting retransplantation, 40 months after the procedure.

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.

Pediatric heart transplantation: immunosuppression and its complications

PURPOSE OF REVIEW

Advances in immunosuppression have contributed to the significant improvements in outcome for pediatric heart transplant recipients in the past two decades. The large increase in the number of available immunosuppressive agents in the past few years mandates that those caring for this complex group of patients remain up to date in this rapidly advancing field.

RECENT FINDINGS

In this review, we evaluate recent studies of immunosuppressive efficacy, end-organ toxicities, and side effects of nonspecific immunosuppression with currently used regimens. In addition, we examine new findings that attempt to define the genetic contribution to rejection profiles, immunosuppressive efficacy, and drug disposition after heart transplantation in children.

SUMMARY

The continuous evaluation of new immunosuppressive regimens will help to elucidate the optimal treatment regimens for pediatric heart transplant recipients. Unfortunately, the small number of transplantations means that it is unlikely that pivotal randomized, controlled trials will ever be performed in this population. Extrapolation from adult controlled trials and experience from other pediatric solid organ transplant recipient populations will continue to provide important contributions to our knowledge base. Understanding the genetic contribution to graft and patient outcomes may help us tailor immunosuppressive therapy for the individual patient.