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.

Subsequent kidney transplant after pediatric heart transplant: Prevalence and risk factors

Pediatric heart failure and transplantation carry associated risks for kidney failure and potential need for kidney transplant following pediatric heart transplantation (KT/pHT). This retrospective, United Network of Organ Sharing study of 10,030 pediatric heart transplants (pHTs) from 1987 to 2020 aimed to determine the incidence of waitlisting for and completion of KT/pHT, risk factors for KT/pHT, and risk factors for nonreceipt of a KT/pHT. Among pHT recipients, 3.4% were waitlisted for KT/pHT (median time of 14 years after pHT). Among those waitlisted, 70% received a KT/pHT, and 18% died on the waitlist at a median time of 0.8 years from KT/pHT waitlisting (median age of 20 years). Moderate-high sensitization at KT/pHT waitlisting (calculated panel reactive antibody, ≥ 20%) was associated with a lower likelihood of KT/pHT (adjusted hazard ratio, 0.67; 95% confidence interval, 0.47-0.95). Waitlisting for heart transplantation simultaneously with kidney transplant (adjusted hazard ratio, 3.73; 95% confidence interval, 2.01-6.92) was associated with increased risk of death on the KT/pHT waitlist. While the prevalence of KT/pHT is low, there is substantial mortality among those waitlisted for KT/pHT. These findings suggest a need to consider novel risk factors for nonreceipt of KT/pHT and death on the waitlist in prioritizing criteria/guidelines for simultaneous heart-kidney transplantation.

Clinical approach to antibody-mediated rejection from the pediatric heart transplant society

This document is designed to outline the definition, pathogenesis, diagnostic modalities and therapeutic measures to treat antibody-mediated rejection in children postheart transplant METHODS: Literature review was conducted by a Pediatric Heart Transplant Society (PHTS) working group to identify existing pediatric and adult studies on antibody-mediated rejection (AMR). In addition, the centers participating in PHTS were asked to submit their approach to diagnosis and management of pediatric AMR. This document synthesizes information gathered from both these sources to highlight a practical approach to diagnosing and managing a child with AMR postheart transplant. This document may not represent the practice at all centers in the PHTS and serves as a starting point to understand an approach to this clinical scenario.

Selumetinib for Refractory Pulmonary and Gastrointestinal Bleeding in Noonan Syndrome

A 15-year-old-boy with Noonan syndrome and status post orthoptic heart transplant developed mixed mitral valve disease and underwent mechanical mitral valve replacement 6 months before presentation with acute respiratory distress. He developed massive pulmonary hemorrhage that required veno-venous extracorporeal membrane oxygenation (ECMO) support. He had a prolonged anticoagulation free ECMO course of 4 weeks, with ongoing recurrent pulmonary hemorrhage and underwent several rounds of coil embolization of aortopulmonary collaterals. ECMO course was complicated by significant nasopharyngeal bleeding that required embolization of the sphenopalatine artery. Shortly after decannulation, he developed massive gastrointestinal and peritoneal hemorrhage that was treated by embolization of the left gastric artery and a branch of the internal iliac artery. His bleeding was attributed to neo-angiogenesis. Initial treatment with propranolol was unsuccessful. Subsequent treatment with interferon α 2b demonstrated efficacy, but severe neutropenia required cessation of therapy. Because functional alterations of the rat sarcoma virus-mitogen activated protein kinase signaling pathway and protein tyrosine phosphatase nonreceptor type (PTPN11) mutations in Noonan syndrome are known to be associated with neo-angiogenesis, we used the mitogen-activated protein kinase inhibitor selumetinib as a gene-targeted therapy with the hope of controlling bleeding and inhibiting neo-angiogenesis. After initiation of selumetinib, bleeding stopped and allowed the patient to be discharged from the hospital on dipyridamole as antiplatelet prophylaxis for his mechanical mitral valve. He had no further bleeding episodes through 1 year after hospital discharge.

Heart Transplantation in Children With Down Syndrome

Background

Children with Down syndrome (DS) have a high risk of cardiac disease that may prompt consideration for heart transplantation (HTx). However, transplantation in patients with DS is rarely reported. This project aimed to collect and describe waitlist and post– HTx outcomes in children with DS.

Methods and Results

This is a retrospective case series of children with DS listed for HTx. Pediatric HTx centers were identified by their participation in 2 international registries with centers reporting HTx in a patient with DS providing detailed demographic, medical, surgical, and posttransplant outcome data for analysis. A total of 26 patients with DS were listed for HTx from 1992 to 2020 (median age, 8.5 years; 46% male). High‐risk or failed repair of congenital heart disease was the most common indication for transplant (N=18, 69%). A total of 23 (88%) patients survived to transplant. All transplanted patients survived to hospital discharge with a median posttransplant length of stay of 22 days. At a median posttransplant follow‐up of 2.8 years, 20 (87%) patients were alive, 2 (9%) developed posttransplant lymphoproliferative disorder, and 8 (35%) were hospitalized for infection within the first year. Waitlist and posttransplant outcomes were similar in patients with and without DS (P=non‐significant for all).

Conclusions

Waitlist and post‐HTx outcomes in children with DS selected for transplant listing are comparable to pediatric HTx recipients overall. Given acceptable outcomes, the presence of DS alone should not be considered an absolute contraindication to HTx.

Novel use of cangrelor in pediatrics: A pilot cohort study demonstrating use in ventricular assist devices

Thromboembolic events and bleeding are major sources of morbidity among pediatric patients supported on a ventricular assist device (VAD). Pharmacokinetics and pharmacodynamics of enteral antiplatelet agents are affected and variable due to erratic enteral absorption in end-stage heart failure and VAD circulation. Additionally, 20%-40% of the population are poor metabolizers of clopidogrel, a prodrug, making cangrelor an alternative when antiplatelet therapy is crucial. Cangrelor has been used effectively and safely for short durations in adults during percutaneous coronary interventions, but the use of cangrelor is still under investigation in pediatrics. This case series utilized cangrelor, a novel short-acting, reversible, intravenous P2Y₁₂ platelet inhibitor in managing pediatric patients supported with a VAD. We performed a retrospective, single-center review of patients admitted to a tertiary medical center with end-stage heart failure requiring mechanical circulatory support and concomitant cangrelor administration between January 2019 and March 2020. Platelet function testing, cangrelor dose, bleeding complications, thromboembolic events, and frequency of circuit interventions during the use of cangrelor were recorded. Optimal platelet reactivity, defined as P2Y₁₂ < 180 platelet reaction units (PRU), was measured with serial point-of-care testing (VerifyNow). Seven patients, median age of 4.9 years, met the above criteria. Three patients had a diagnosis of complex congenital heart disease. Four patients had dilated or restrictive cardiomyopathy. All patients were on continuous flow VADs. The median VAD duration was 84.5 days (IQR 61.5-103). The median duration on cangrelor was 43 days (IQR 8-70). The median cangrelor dose to reach the therapeutic threshold was 0.75 μg/kg/min with the mean P2Y₁₂ , while on cangrelor of 164.75 PRU. Bleeding complications included mild gastrointestinal bleeding and hematuria. There was one patient with pump thrombosis requiring intervention. There were no cerebrovascular events while on cangrelor. We report the first successful long-term use of cangrelor in pediatric patients. The reversibility and short half-life of cangrelor make it a feasible antiplatelet agent in selected patients. This data supports the use of cangrelor in children as a viable antiplatelet option; with minimal bleeding complications and no cerebrovascular events demonstrated in this cohort.

ISHLT consensus statement on donor organ acceptability and management in pediatric heart transplantation

The number of potential pediatric heart transplant recipients continues to exceed the number of donors, and consequently the waitlist mortality remains significant. Despite this, around 40% of all donated organs are not used and are discarded. This document (62 authors from 53 institutions in 17 countries) evaluates factors responsible for discarding donor hearts and makes recommendations regarding donor heart acceptance. The aim of this statement is to ensure that no usable donor heart is discarded, waitlist mortality is reduced, and post-transplant survival is not adversely impacted.

Outbreak of Salmonella enterica Goldcoast infection associated with whelk consumption, England, June to October 2013

An increase in the number of cases of Salmonella enterica serotype Goldcoast infection was observed in England during September 2013. A total of 38 cases were reported, with symptom onset dates between 21 June and 6 October 2013. Epidemiological, environmental, microbiological and food chain evidence all support the conclusion that this outbreak was associated with eating whelks processed by the same factory. Whelks are a novel vehicle of Salmonella infection and should be considered when investigating future outbreaks.

A prospective multicenter phase II trial of systemic ADH-1 in combination with melphalan via isolated limb infusion (M-ILI) in patients with advanced extremity melanoma

9025^

Background: ILI with melphalan dosing corrected for ideal body weight (IBW) is a well tolerated treatment for patients with in-transit extremity melanoma with an approximate 30% CR and 44% overall response rate. ADH-1 is a cyclic pentapeptide that disrupts N-cadherin adhesion complexes. ADH-1 when given systemically in a preclinical model with regional melphalan demonstrated synergistic antitumor activity and had minimal toxicity in a Phase I trial with M-ILI. Methods:AJCC stage IIIB or IIIC extremity melanoma patients were treated with 4000mg of ADH-1 administered systemically on Day 1 and 8 in addition to standard dose M-ILI corrected for IBW on Day 1. Drug pK, and N-cadherin IHC staining were performed on pretreatment tumor from all patients. The primary endpoint was response at 12 weeks determined by modified RECIST. Results: 46 patients were enrolled over 15 months at 4 institutions. Thirty-four patients are presently evaluable for 12 week response. In field responses include 14 CRs (41.2%%), 9 PRs (26.5%), 5 SDs (14.7%), and 6 PDs (17.6%). The OR rate was 67.7% and at a median follow-up of 30 weeks, 8 patients have sustained CRs over 6 months. Of 34 patients, 9 have developed disease outside the region of infusion (median time to progression 12 weeks) at median follow-up 36 weeks. N-cadherin was detected in 20 of 25 (80%) pretreatment tumor samples. Grade IV toxicities included CPK elevation (4), neutropenia (1), acute respiratory distress syndrome (1), pneumonitis (1), and pulmonary infiltrate (1). There were no limb losses or compartment syndromes. Conclusions:This study is not only the first prospective multi-center ILI trial but also the first ILI study to incorporate a targeted agent in an attempt to augment anti-tumor responses. The treatment was well tolerated with CR and OR rates that appear to be significantly improved from standard M-ILI alone. Targeting N-cadherin may represent a novel strategy for improving melanoma sensitivity to chemotherapeutic agents and warrants further investigation in a large randomized multi-center trial.

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ASCO Conflict of Interest Policy and Exceptions

In compliance with the guidelines established by the ASCO Conflict of Interest Policy (J Clin Oncol. 2006 Jan 20;24[3]:519–521) and the Accreditation Council for Continuing Medical Education (ACCME), ASCO strives to promote balance, independence, objectivity, and scientific rigor through disclosure of financial and other interests, and identification and management of potential conflicts. According to the ASCO Conflict of Interest Policy, the following financial and other relationships must be disclosed: employment or leadership position, consultant or advisory role, stock ownership, honoraria, research funding, expert testimony, and other remuneration (J Clin Oncol. 2006 Jan 20;24[3]:520). The ASCO Conflict of Interest Policy disclosure requirements apply to all authors who submit abstracts to the Annual Meeting.

For clinical trials that began accrual on or after April 29, 2004, ASCO's Policy places some restrictions on the financial relationships of principal investigators (J Clin Oncol. 2006 Jan 20;24[3]:521). If a principal investigator holds any restricted relationships, his or her abstract will be ineligible for placement in the 2009 Annual Meeting unless the ASCO Ethics Committee grants an exception. Among the circumstances that might justify an exception are that the principal investigator (1) is a widely acknowledged expert in a particular therapeutic area; (2) is the inventor of a unique technology or treatment being evaluated in the clinical trial; or (3) is involved in international clinical oncology research and has acted consistently with recognized international standards of ethics in the conduct of clinical research. NIH-sponsored trials are exempt from the Policy restrictions. Abstracts for which authors requested and have been granted an exception in accordance with ASCO's Policy are designated with a caret symbol (^) in the Annual Meeting Proceedings.

For more information about the ASCO Conflict of Interest Policy and the exceptions process, please visit www.asco.org/conflictofinterest .