Pediatric Cardiology Fellowship Standards for Training in Exercise Medicine and Curriculum Outline

Over the past 2 decades, fundamentals of exercise medicine, including clinical exercise testing, assessment and promotion of physical activity, exercise prescription, and supervised exercise training/rehabilitation programming have demonstrated considerable clinical value in the management of children and adolescents with congenital and acquired heart disease. Although the principles of exercise medicine have become an integral component in pediatric cardiology, there are no standardized training recommendations for exercise physiology during pediatric cardiology fellowship at this time. Thus, the Pediatric Cardiology Exercise Medicine Curriculum Committee (PCEMCC) was formed to establish core and advanced exercise physiology training recommendations for pediatric cardiology trainees. The PCEMCC includes a diverse group of pediatric cardiologists, exercise physiologists, and fellowship program directors. The expert consensus training recommendations are by no means a mandate and are summarized herein, including suggestions for achieving the minimum knowledge and training needed for general pediatric cardiology practice.

Cardiopulmonary Exercise Performance in the Pediatric and Young Adult Population Before and During the COVID-19 Pandemic

Physical activity (PA) decreased and sedentary behavior (SB) increased in the pediatric population during the Coronavirus Disease 2019 (COVID-19) pandemic. We examined the effects of PA and SB on cardiopulmonary exercise performance in children, adolescents and young adults both with and without underling cardiac disease, and hypothesized that there will be a change in aerobic and physical working capacity during the pandemic. This was a single-center retrospective longitudinal cohort study in patients age 6-22 years who underwent serial maximal cardiopulmonary exercise stress testing before and during the COVID-19 pandemic. Metabolic variables were obtained; PA and SB data were extracted from clinic notes. A total of 122 patients (60% male) underwent serial exercise testing with a median age of 14 years at the first CPET. Predicted peak aerobic capacity significantly decreased among both females and males during the pandemic, even after adjusting for changes in somatic growth. There was no significant change in physical working capacity during the pandemic. Patients who were more aerobically fit experienced a greater decrease in aerobic capacity during the pandemic compared to those less fit. In conclusion, cardiopulmonary exercise performance, notably aerobic activity, decreased during the COVID-19 pandemic in children, adolescents and young adults compared to pre-pandemic values. This decline was most notable in those with the highest pre-pandemic aerobic capacity values and was independent of somatic growth or changes in BMI. This study has public health implications and demonstrates the importance of PA on overall cardiovascular health.

Trends in Sales Volumes of Cancer Medicines in Six Asian Countries Working Toward Universal Health Coverage

Background: In low- and middle-income (LMIC), medicines represent an important proportion of total out-of-pocket expenditures on health care and should therefore be a key target for financial protection through inclusion in benefit packages under universal health coverage (UHC). For antineoplastic medicines, this need will become even more urgent with the increasing incidence of cancers in LMIC and the availability of new, highly priced cancer. Previous studies have shown that countries have listed cancer medicines recommended in the World Health Organization (WHO) essential medicines list (EML) in their national EMLs. However, little is known about use of these medicines at country level and changes in use over time as countries work toward UHC. Aim: To analyze trends in sales volumes of cancer medicines in China, Indonesia, Kazakhstan, Malaysia, the Philippines and Thailand between 2006 and 2017. Methods: Using quarterly data from IQVIA (former IMS and Quintiles) on sales volumes in 6 middle-income Asian countries of cancer medicines (ATC-L01/02) included in the 2017 WHO EML, we estimated annual sales by international nonproprietary name, year and country. Sales volumes were estimated in total milligrams and total defined daily doses (DDD) per new cancer case. The reference DDD were taken from the German Institute of Medical Documentation and Information. We adjusted total mg and DDD by the total number of new cancer cases per country in 2012 ( Globocan 2012 ). Results: The 2017 WHO EML contains 49 medicines in the antineoplastic section; 40 of them were used in 1 or more countries included in the study. Availability of these 40 medicines ranged from 33 in Indonesia to 40 in the Philippines. The median percentage increase in sales volumes between 2006 and 2017 ranged from 42% in Thailand to 94% in Indonesia. Use of new, high-priced medicines such as trastuzumab and rituximab increased more than 90% and 72% in all countries, respectively, during the study period. Limitations: National sales volumes are extrapolated from standardized audits of procurement and sales data in sample facilities and/or distribution data supplied by wholesalers in each country and may underestimate actual sales. Given different indications for which a cancer medicine can be used and highly individualized antineoplastic treatment regimens and dosages, standardized DDD do not represent actual prescribed daily doses. Growth rates will reflect the place of the medicine within the national treatment guidelines and healthcare delivery capacity. Conclusion: This study provides evidence that use of WHO-recommended essential medicines for cancers increased in 6 Asian countries working toward UHC. Many factors are likely to have contributed to this outcome, including improvements in diagnosis and treatments. The next step in this study will be to assess the role of insurance coverage changes as a factor contributing to changes in utilization of cancer medicines.

Bi-allelic inactivation is more prevalent at relapse in multiple myeloma, identifying RB1 as an independent prognostic marker

The purpose of this study is to identify prognostic markers and treatment targets using a clinically certified sequencing panel in multiple myeloma. We performed targeted sequencing of 578 individuals with plasma cell neoplasms using the FoundationOne Heme panel and identified clinically relevant abnormalities and novel prognostic markers. Mutational burden was associated with maf and proliferation gene expression groups, and a high-mutational burden was associated with a poor prognosis. We identified homozygous deletions that were present in multiple myeloma within key genes, including CDKN2C, RB1, TRAF3, BIRC3 and TP53, and that bi-allelic inactivation was significantly enriched at relapse. Alterations in CDKN2C, TP53, RB1 and the t(4;14) were associated with poor prognosis. Alterations in RB1 were predominantly homozygous deletions and were associated with relapse and a poor prognosis which was independent of other genetic markers, including t(4;14), after multivariate analysis. Bi-allelic inactivation of key tumor suppressor genes in myeloma was enriched at relapse, especially in RB1, CDKN2C and TP53 where they have prognostic significance.

Integration-Free Reprogramming of Lamina Propria Progenitor Cells

Producing induced pluripotent stem cells (iPSCs) from human tissue for use in personalized medicine strategies or therapeutic testing is at the forefront of medicine. Therefore, identifying a source of cells to reprogram that is easily accessible via a simple noninvasive procedure is of great clinical importance. Reprogramming these cells to iPSCs through nonintegrating methods for genetic manipulation is paramount for regenerative purposes. Here, we demonstrate reprogramming of oral mucosal lamina propria progenitor cells from patients undergoing routine dental treatment. Reprogramming was performed utilizing nonintegrating plasmids containing all 6 pluripotency genes (OCT4, SOX2, KLF4, NANOG, LIN28, and cMYC). Resulting iPSCs lacked genetic integration of the vector genes and had the ability to differentiate down mesoderm, ectoderm, and endoderm lineages, demonstrating pluripotency. In conclusion, oral mucosal lamina propria progenitor cells represent a source of cells that can be obtained with minimal invasion, as they can be taken concurrently with routine treatments. The resulting integration-free iPSCs therefore have great potential for use in personalized medicine strategies.

Does the cancer drugs fund lead to faster uptake of cost-effective drugs? A time-trend analysis comparing England and Wales

Background:

The Cancer Drugs Fund (CDF) provides £200 million annually in England for ‘anti-cancer' drugs.

Methods:

We used a controlled pre-/post-intervention design to compare IMS Health dispensing data for 15 cancer drugs (2007–2012) in England vs Wales, stratified by pre-CDF NICE drug approval status (rejected, mixed recommendations, recommended, not appraised).

Results:

The CDF was associated with increased prescribing in England for three of five drugs rejected or with mixed NICE recommendations. The prescribing volume ratios (PVR) ranged from 1.29 (95% CI 1.00, 1.67) for sorafenib to 3.28 (2.59, 4.14) for bevacizumab (NICE rejected) and 0.93 (0.81, 1.06) and 1.35 (1.21, 1.49) for sunitinib and imatinib respectively (mixed recommendations). Post CDF prescribing in England increased for both drugs awaiting NICE appraisal pre-CDF (lapatinib PVR=7.44 (5.81, 9.54), panitumumab PVR=5.40 (1.20, 24.42)) and subsequently rejected. The CDF was not associated with increased prescribing in England of NICE-recommended drugs. The three most recently launched, subsequently recommended drugs were adopted faster in Wales (from pazopanib PVR=0.51 (0.28, 0.96) to abiraterone PVR=0.78 (0.61–0.99)).

Interpretation:

These data indicate that the CDF is used to access drugs deemed not cost-effective by NICE. The CDF did not expedite access to new cost-effective cancer agents prior to NICE approval.

Abstract S3-06: Emergence of constitutively active estrogen receptor mutations in advanced estrogen receptor positive breast cancer

Introduction: The lack of estrogen receptor (ER) expression is the primary cause of de novo resistance of breast cancers to endocrine therapy. In contrast, in most cases of acquired endocrine resistance, ER is expressed and other mechanisms of resistance have been proposed, such as ER mutations. Pre-clinical studies demonstrated a small number of specific point mutations that can enhance ER function. However, the studies on clinical samples performed in the 1990's were limited by small sample size, lack of detailed clinical correlation and lacked the sensitivity of next-generation sequencing (NGS). Therefore, in this study we sought to comprehensively investigate the frequency and functional significance of ER mutations throughout the progression of breast cancer from primary disease to advanced metastatic disease using targeted NGS.

Methods: In this retrospective study, a total of 249 tumor specimens were analyzed. The specimens include 134 ER positive and, as controls, 115 estrogen receptor negative tumors. The estrogen receptor positive samples consist of 58 primary breast cancers and 76 metastatic sample. All tumors were sequenced with high coverage using NGS targeting the coding sequence of ER and an additional 181 cancer-related genes.

Results: Recurring somatic mutations at codons 537 and 538 within the ligand-binding domain of the estrogen receptor were detected in ER positive metastatic tumors. Overall, the frequency of these mutations was 12% (95% CI 6%-21%) in metastatic patients compared with none in the primary cases. In total there were 9 recurring somatic mutations; Y537C (11%), Y537N (33%), Y537S (22%) and D538G (33%). In addition in a small number of paired primary and metastatic samples from the same patient, these mutations were found only in the metastatic specimens. In a subset of heavily pre-treated patients the frequency was 20% (5/25, 95% CI 7%-41%). ER activating mutations were not detected in any stage of ER negative disease. ER alterations were not mutually exclusive with any of the other commonly altered genes and of the most frequently altered genes, all but ER alterations displayed similar frequencies across primary and metastatic specimens. Functional studies in cell line models demonstrated that these ER mutations render ER constitutively active and confer resistance to hormone deprivation, tamoxifen and fulvestrant.

Conclusions: Herein, we reveal functional ER mutations as potential drivers of endocrine resistance during the progression of ER positive breast cancer. The absence of detectable mutations in the primary tumors suggests clonal evolution as the mechanism of resistance. Thus, these mutations have the potential to be an important genetic biomarker of endocrine resistance in ER positive metastatic breast cancer and could assist in clinical decision making as disease progresses. Our findings also underscore the value of repeated biopsies of metastatic lesions. Lastly, since the frequencies of these mutations are substantial when sensitive testing methods are used in the correct clinical context, pre-clinical and clinical studies to identify novel therapeutics that can overcome this resistance are warranted.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr S3-06.

Abstract P6-12-07: Prevalence of propionibacterium acnes and bartonella henselae DNA in patients with inflammatory breast cancer (IBC)

Introduction:

Inflammatory breast cancer (IBC) is a very aggressive variant of breast cancer with a poor prognosis.. Mouse Mammary Tumor-associated Virus (MMTV) and other infectious agents have been considered as possible etiological agents of IBC particularly related to the initial description of higher incidence in women living in rural areas in North Africa. The etiological role of bacteria in this disease has never been explored in spite of the evidence that chronic infections with certain bacteria can facilitate tumors development. We retrospectively evaluated tissue samples from patients with recurrent IBC to identify potential bacterial agents that could play a role in the development and progression of the disease.

Methods:

DNA was isolated from formalin-fixed paraffin embedded samples of 24 Inflammatory Breast Cancer (IBC) patients whose specimen had been submitted for genomic analysis using next-genomic sequencing (Foundation One™). An additional 3 non-IBC patients (lymph node, lung metastatic lesions) were included in the study. Unselected DNA libraries from these samples were pooled and sequenced on a HiSeq-2000 sequencer. Comparing the sequence data to a reference of 5,569 bacterial and viral genomic sequences identified the presence of Propionibacterium acnes, Ralstonia pickettii and Methylobacterium consequently, we enriched the DNA libraries for the presence of these species as well as bacterial rRNA genes using hybrid capture with synthesized oligonucleotide baits and sequenced the enriched libraries.

Results:

Twenty three IBC patients and 3 non-IBC breast cancer patients were included in the study. Tissue specimens included, 14 chest wall and skin;6 breast, 2 lymph nodes; 1 liver, 1 lung, 1 pleural fluid, 1 brain. In 16 out of the 23 IBC (70%) of specimens we detected bacteria DNA. Propionibacterium acnes were detected in 12 cases. Bartonella henselae was detected in 1 out of the 23 IBC specimens. Furthermore, additional detected species included Ralstonia pickettii (3 cases) and Pseudomonas aeruginosa (2). No bacteria were detected in samples from non-IBC breast cancer patients.

Conclusions:

In this study, we identified Propionibacterium acnes and Bartonella henselae in samples from IBC patients. The anaerobic Gram-positive bacterium P. acnes is ubiquitously found in sebaceous follicles of the human skin. Recent reports showed that P. acnes was present in a high number of cancerous prostate tissue samples. It has been suggested that P. acnes may be a contributing factor to the initiation or progression of prostate cancer. Bartonella is a Gram-negative bacteria usually associated with cat-scratch disease, urban trench fever, bacillary angiomatosis-peliosis and endocarditis. Some reports that have showed some similarities between cat scratch disease and inflammatory breast cancer. Our results suggested that P. acnes or Bartonella henselae infections might contribute to the clinical and pathological characteristics of IBC, associated with rapid spread of the breast tumor cells through the lymphatic system.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P6-12-07.

Abstract P1-08-18: PIK/AKT/MTOR pathway activation in triple negative breast cancer and outcomes with matched therapy in phase I clinical trials: Response in both patients with and without direct molecular alterations

Introduction

The PI3K/AKT/MTOR pathway is a known driver in triple negative breast cancers (TNBC). We analyzed patients with TNBC seen in our Phase I clinic including molecular subtyping and correlation with response to therapies targeting the PI3K/AKT/mTOR pathway.

Methods

Patients with advanced TNBC [negative (<1%) expression for estrogen and progesterone receptors and negative Her 2 (</ = 1+ by IHC or non-amplified by FISH)] whose tumors had undergone molecular profiling (including PIK3CA/PTEN mutation analysis and/or PTEN immunohistochemistry (IHC)). We evaluated sequential patients seen in the Phase I clinic at M.D. Anderson Cancer Center treated on at least one Phase I clinical trial and correlated molecular status with clinical outcomes on therapy. Molecular profiling methods including hotspot analysis, next generation sequencing and IHC.

Results

Forty-four patients (median age 56, range 27-81; all female; white race76%) with a median of 2 (0-7) prior therapies (40% received ≥3 prior systemic therapies) and 2 metastatic sites (range, 1-6) were included. Histology: invasive ductal carcinoma 29 (66%), metaplastic 12 (27%), other 3 (7%). Nine out of 42 patients tested (19%) had a PIK3CA mutation and, 11 out of 33 patients tested (33%) demonstrated PTEN loss on IHC and 2 patients had PTEN mutations. Altogether, 21 out of 44 patients had at least one alteration in the PI3K/AKT/mTOR pathway. Sixteen of these 21 patients received “matched” therapy consisting of at least one agent targeting the PI3K/AKT/mTOR pathway. Four out of 16 patients (25%) with at least one molecular alteration, treated with one or more regimens containing at least one agent targeting the PI3K/AKT/mTOR pathway (“matched” therapy), demonstrated clinical benefit: complete response (CR) (N = 1)/partial response (PR) (N = 1)/stable disease ≥ 6 months (SD) (N = 2). Similarly, three out of 12 patients (25%) who did not demonstrate a direct molecular alteration in the PI3K/AKT/mTOR pathway and who were treated with PI3K-directed therapy, had either CR (N = 1)/PR (N = 1)/SD ≥ 6 months (N = 1). Twenty-eight patients received PI3K/AKT/mTOR pathway directed therapy yielding CR (N = 2), PR (N = 3) and CR/PR/ SD ≥ 6 months (N = 1) while those who received other therapies had CR (N = 0), PR (N = 1) and CR/PR/SD>6mo (N = 3)and a median TTF of 3.1 (2.1-4.8) vs. 1.8 (1.4-2.5) months (p = 0.23).

Conclusions

A significant percentage of patients with TNBC demonstrate a direct alteration in the PI3K/AKT/mTOR pathway. Our data shows that PI3K-directed therapies benefit both those patients with and without direct molecular alterations in this pathway. Further molecular testing results will be presented. This data suggests that there may be additional molecular alterations that activate PI3K/AKT/mTOR in patients with TNBC.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P1-08-18.

Abstract PD02-07: Next-generation sequencing of FFPE breast cancers demonstrates high concordance with FISH in calling HER2 amplifications and commonly detects other clinically relevant genomic alterations

Background: As more therapies targeting genomic alterations become available, next-generation sequencing (NGS) is increasingly performed in tumor types where mutational status may drive treatment choice. In addition to its ability to identify base substitutions, insertions and deletions across entire exons, NGS can detect relevant copy number changes such as amplification of HER2 in breast tumors. However, for NGS to be clinically applicable, it must reliably analyze FFPE tumor samples and show concordance with the best current diagnostic methods.

Methods: To confirm a clinical role for NGS in detecting copy number alterations, we identified 35 FFPE invasive breast carcinomas previously tested for HER2 status by FISH, including 15 HER2 positives (≥7 copies) and 20 HER2 negatives (<4 copies) and sequenced 3,230 exons of 182 cancer genes including HER2, in a CLIA certified lab (Foundation Medicine). Average coverage depth of >900X uniquely-mapping reads was obtained. Sequence data were analyzed for HER2 copy number (blinded to FISH results) based on a statistical model using allele frequencies and coverage depth of HER2 exons versus a process-matched normal control, classifying cases as HER2 positive (≥6 average copies), HER2 negative (<4 copies), intermediate (4–5 copies) or unknown (<20% tumor purity). The data were also analyzed for additional clinically relevant genomic alterations.

Results: High concordance was noted between HER2 copy number status determined by FISH and NGS: 30 of the 35 samples were classified as positive or negative by NGS, 1 was classified as intermediate and 4 as unknown due to low purity. Using FISH as a gold standard, NGS HER2 calls demonstrated an accuracy of 97% (29/30, 95% CI 83–99%), 93% sensitivity (13/14, 95% CI 69–99%) and 100% specificity (16/16, 95% CI 81–100%). One discordant case was noted (FISH positive, NGS negative). Furthermore, NGS revealed 70 additional alterations (38 base substitutions, 10 insertions/deletions, 22 copy number alterations) in 23 cancer genes (an average of 2.0 alterations per sample). Genomic alterations that predict sensitivity or resistance to approved or experimental targeted therapies and thus plausibly guide treatment decisions were found in 69% of patients. These include PIK3CA (16 cases, PI3 kinase/mTOR inhibitors), PTEN (3 cases, PI3K/AKT/mTOR inhibitors), KRAS (1 case, resistance to cetuximab and panitumumab), and NF1 (1 case, mTOR/MAPK inhibitors) plus amplifications of CCND1 (4 cases, CDK4 inhibitors), FGFR1 (3 cases, FGF inhibitors) and MCL1 (3 cases, BCL-2 inhibitors, resistance to anti-tubulin therapies). Four cases included co-amplification of RARA with HER2.

Conclusions: We conclude that HER2 status can be reliably determined by NGS on FFPE breast cancers and that NGS uncovers additional actionable genomic alterations that could impact disease management in a high proportion of patients. Further evaluation of NGS as a guide to therapy in breast cancer is warranted.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr PD02-07.

‘Young’ Oral Fibroblasts Are Geno/Phenotypically Distinct

Wound healing within the oral mucosa results in minimal scar formation compared with wounds within the skin. We have recently demonstrated distinct differences in the aging profiles of cells (oral mucosal and patient-matched skin fibroblasts) isolated from these tissues. We hypothesized that the increased replicative potential of oral mucosal fibroblasts may confer upon them preferential wound-healing capacities. Passage-matched early cultures of oral mucosal fibroblasts and skin fibroblasts demonstrated distinct gene expression profiles, with several genes linked to wound healing/tissue repair. This was related to an increased ability of the ‘replicatively younger’ oral mucosal fibroblasts to repopulate a wound space and reorganize their surrounding extracellular matrix environment, key activities during the wound-healing process. We conclude that oral mucosal fibroblasts exhibit a preferential healing response in vivo, due to their ‘replicatively younger’ phenotype when compared with that of patient-matched skin fibroblasts.

Constitutional translocation breakpoint mapping by genome-wide paired-end sequencing identifies HACE1 as a putative Wilms tumour susceptibility gene

BACKGROUND

Localisation of the breakpoints of chromosomal translocations has aided the discovery of several disease genes but has traditionally required laborious investigation of chromosomes by fluorescent in situ hybridisation approaches. Here, a strategy that utilises genome-wide paired-end massively parallel DNA sequencing to rapidly map translocation breakpoints is reported. This method was used to fine map a de novo t(5;6)(q21;q21) translocation in a child with bilateral, young-onset Wilms tumour.

METHODS AND RESULTS

Genome-wide paired-end sequencing was performed for approximately 6 million randomly generated approximately 3 kb fragments from constitutional DNA containing the translocation, and six fragments in which one end mapped to chromosome 5 and the other to chromosome 6 were identified. This mapped the translocation breakpoints to within 1.7 kb. Then, PCR assays that amplified across the rearrangement junction were designed to characterise the breakpoints at sequence-level resolution. The 6q21 breakpoint transects and truncates HACE1, an E3 ubiquitin-protein ligase that has been implicated as a somatically inactivated target in Wilms tumourigenesis. To evaluate the contribution of HACE1 to Wilms tumour predisposition, the gene was mutationally screened in 450 individuals with Wilms tumour. One child with unilateral Wilms tumour and a truncating HACE1 mutation was identified.

CONCLUSIONS

These data indicate that constitutional disruption of HACE1 likely predisposes to Wilms tumour. However, HACE1 mutations are rare and therefore can only make a small contribution to Wilms tumour incidence. More broadly, this study demonstrates the utility of genome-wide paired-end sequencing in the delineation of apparently balanced chromosomal translocations, for which it is likely to become the method of choice.

Increased Oral Fibroblast Lifespan Is Telomerase-independent

Oral mucosal wound-healing is characterized by rapid re-epithelialization and remodeling, with minimal scar formation. This may be attributed to the distinct phenotypic characteristics of the resident fibroblasts. To test this hypothesis, we investigated patient-matched oral mucosal and skin fibroblasts. Compared with skin fibroblasts, oral mucosal fibroblasts had longer proliferative lifespans, underwent more population doublings, and experienced senescence later, which was directly related to longer telomere lengths within oral mucosal fibroblasts. The presence of these longer telomeres was independent of telomerase expression, since both oral oral mucosal fibroblasts and skin fibroblasts were negative for active telomerase, as assessed according to the Telomeric Repeat Amplification Protocol. This study has demonstrated that, compared with skin fibroblasts, oral mucosal fibroblasts are ‘younger’, with a more embryonic/fetal-like phenotype that may provide a notable advantage for their ability to repair wounds in a scarless fashion.

Serum alkaline phosphatase reflects post-Fontan hemodynamics in children

Although survivors of Fontan palliation for a single ventricle are known to have lower cardiac index than patients with two-ventricle surgical reconstructions, it is unclear whether two frequently observed sequelae, short stature and protein-losing enteropathy (PLE), have hemodynamic origins. A serum marker that reflects hemodynamic status would be a tremendous asset in the long-term management of children with these sequelae. The authors recently noted severely reduced total alkaline phosphatase (TALP) levels in two children with early-onset PLE after Fontan operations, both of whom had low cardiac output at cardiac catheterization. Catheter-based or surgical interventions that rapidly increased cardiac output in these two patients resulted not only in relief of PLE but also in a prompt TALP rise. To examine whether the apparent correlation of low TALP with impaired cardiac output also is seen in Fontan patients without PLE, this study retrospectively examined the TALP data from two other Fontan patients who underwent cardiac catheterization specifically to assess the potential benefit of vasodilator therapy. The TALP levels were abnormally low in both cases but increased after up-titration of angiotensin-converting enzyme inhibition. Serum TALP activity, an indicator of osteoblastic function particularly in pre-adolescence, may be a marker of low cardiac output after a Fontan operation.