Exercise cardiac MRI unmasks cardiac dysfunction in childhood and adolescent cancer survivors with reduced cardiopulmonary fitness

Background

Young cancer survivors are at increased risk of impaired cardiopulmonary fitness (VO2peak) and heart failure. Assessment of exercise cardiac reserve may reveal sub-clinical abnormalities that better explain impairments in fitness and long term heart failure risk.

Purpose

To investigate the presence of impaired VO2peak in pediatric cancer survivors with increased risk of heart failure, and to assess its relationship with resting cardiac function and cardiac reserve

Methods

Twenty pediatric cancer survivors (aged 8–24 years) treated with anthracycline chemotherapy underwent cardiopulmonary exercise testing to quantify VO2peak, with a value <85% of predicted defined as impaired VO2peak. Resting cardiac function was assessed using 3-dimensional echocardiography, with cardiac reserve quantified from resting and peak exercise heart rate (HR), stroke volume index (SVi) and cardiac index (CI) using exercise cardiac magnetic resonance imaging.

Results

12 of 20 survivors (60%) had impaired VO2peak (97±14% vs. 70±16% of age and gender predicted). There were no differences in echocardiographic or CMR measurements of resting cardiac function between survivors with normal or impaired VO2peak. However, those with reduced VO2peak had diminished cardiac reserve, with a lesser increase in CI (Fig. 1A) and SVi (Fig. 1B) during exercise (Interaction P=0.001 for both), whilst the HR response was similar (Fig. 1C; P=0.71).

Conclusions

Resting measures of cardiac function are insensitive to significant cardiac dysfunction amongst pediatric cancer survivors with reduced VO2peak. Measures of cardiopulmonary fitness and cardiac reserve may aid in early identification of survivors with heightened risk of long-term heart failure.

Figure 1

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): National Heart Foundation

432 Traditional markers of myocardial dysfunction fail to detect marked reductions in physical capacity amoung chemotherapy patients

Methods

95 patients who were due to commence anti-cancer treatment (n = 58 anthracycline chemotherapy for breast cancer; n = 25 Bruton’s tyrosine kinase inhibitor and n = 12 allogeneic stem cell transplant for haematological cancers) completed a pre-treatment and follow-up assessment within 6 months of initiating treatment. Changes in echocardiographic measures of LV function (LVEF, GLS), cardiac biomarkers (troponin and BNP) and cardiopulmonary exercise test (CPET, VO2peak) were measured.

Results

Of 95 participants who underwent baseline testing, follow-up CPET and echocardiography data was available in 89 participants. LV function was normal prior to treatment (LVEF 61.5 ± 5.9%; GLS -19.4 ± 2.3) but VO2peak (23.4 ± 6.5ml/kg/min) was only 83 ± 21% (range 47-146%) of age-predicted. After treatment, we observed marked reductions in fitness (Δ-2.1 ± 3.7 ml/kg/min or -9 ± 15%, P < 0.001) which was associated with small non-clinically significant changes in LV function (LVEF Δ-2.4 ± 6.4% P = 0.001; GLS Δ-0.5 ± 1.9 P = 0.018). Troponin was increased significantly (4.0 ± 5.5 to 23.5 ± 22.5ng/ml, P < 0.001), with no change in BNP (37.5 ± 31.4 to 32.7 ± 22.0pg/ml, P = 0.87). Current diagnostic criteria for cardiac toxicity were not met in any patient despite some patients developing disabling reductions in functional capacity (VO2peak < 16ml/min/kg).

Conclusion

Despite normal resting LV function prior to commencing treatment VO2peak was below age predicted. Treatment further impaired exercise cardiovascular function with minimal impact on resting measures of LV function. The assessment of cardiovascular function using CPET prior to, and following chemotherapy may be a more sensitive means of identifying patients at increased risk of future heart failure.

P5 Clinical utility of stress echocardiography in remote indigenous and non-indigenous populations: a 10-year study in central Australia

Background

Central Australia is a vast, geographical region spanning some 830,000 square kilometres. It is the most populous Indigenous region in Australia (44%) and a great distance from tertiary centres (1,500km). Non-invasive testing is important in this setting due to the high prevalence of cardiovascular disease and long-distance travel required for coronary angiography, the latter with significant logistical, financial, and cultural barriers. Although stress echocardiography has been extensively validated as a long-term prognostic tool in selected populations, we are not aware of prior studies in remote Indigenous and non-Indigenous individuals.

Purpose

To determine whether stress echocardiography can adequately risk stratify and quantify the long-term prognosis of Indigenous and non-Indigenous individuals in remote Central Australia.

Methods

Consecutive individuals undergoing stress echocardiography in Central Australia between 2007 and 2017 were included. Exercise or dobutamine stress echocardiography was performed and reported via standard protocols.  Individuals were followed up for the primary outcome of all-cause mortality.

Results

One thousand and eight patients (54% Indigenous, 63% dobutamine stress) were included. Indigenous patients were younger, more likely to be female, and had a greater prevalence of cardiometabolic comorbidities (p < 0.05 for all). Overall, 797 (79%) patients had no abnormality during rest or stress echocardiography, with no difference according to ethnicity (p > 0.05).  After a mean follow up of 3.5 ± 2.4 years, 54 (5%) of patients were deceased; 127 (14%) patients underwent revascularization and were censored from follow-up. In patients with a normal test, annual mortality averaged 1.3% over 5 years of follow up, with annual mortality being significantly higher in Indigenous compared to non-Indigenous individuals (2.0% vs 0.6% respectively). Individuals with either ischemia or scar had a significantly worse long-term outcome compared to those with a normal test (Figure). In multivariate analyses, increasing age (HR 1.04 [95% CI 1.01-1.08]), chronic kidney disease (HR 4.83 [1.79-13.02]), and lack of ACEI/ARB use (HR 0.19 [95% CI 0.09-0.42]) were associated with all-cause mortality. Although Indigenous ethnicity was a univariate predictor of mortality, this association was attenuated and non-significant in multivariate analyses.

Conclusion

Indigenous patients in remote Central Australia with a normal stress echocardiogram had a significantly higher annual rate of mortality compared to their non-Indigenous counterparts. However, this association may be in large part due to comorbid conditions. A normal test in Indigenous individuals was still able to adequately risk-stratify and identify a lower risk group of patients in whom ongoing local medical management and focusing on cardiometabolic risk factor reduction is likely to be appropriate.

Abstract P5 Figure. Kaplan Meier survival curve

Investigation of faecal volatile organic metabolites as novel diagnostic biomarkers in inflammatory bowel disease

BACKGROUND

The aetiology of inflammatory bowel disease (IBD) remains poorly understood. Recent evidence suggests an important role of gut microbial dysbiosis in IBD, and this may be associated with changes in faecal volatile organic metabolites (VOMs).

AIM

To describe the changes in the faecal VOMs of patients with IBD and establish their diagnostic potential as non-invasive biomarkers.

METHODS

Faecal samples were obtained from 117 people with Crohn's disease (CD), 100 with ulcerative colitis (UC), and 109 healthy controls. Faecal VOMs were extracted using solid-phase micro-extraction and analysed by gas chromatography mass spectrometry. Data analysis was carried out using partial least squares-discriminate analysis (PLS-DA) to determine class membership based on distinct metabolomic profiles.

RESULTS

The PLS-DA model showed clear separation of active CD from inactive disease and healthy controls (P < 0.001). Heptanal, 1-octen-3-ol, 2-piperidinone and 6-methyl-2-heptanone were up-regulated in the active CD group [variable important in projection (VIP) score 2.8, 2.7, 2.6 and 2.4, respectively], while methanethiol, 3-methyl-phenol, short-chain fatty acids and ester derivatives were found to be less abundant (VIP score of 3.5, 2.6, 1.5 and 1.2, respectively). The PLS-DA model also separated patients with small bowel CD from healthy controls and those with colonic CD from UC (P < 0.001). In contrast, less distinct separation was observed between active UC, inactive UC and healthy controls.

CONCLUSIONS

Analysis of faecal volatile organic metabolites can provide an understanding of gut metabolomic changes in IBD. It has the potential to provide a non-invasive means of diagnosing IBD, and can differentiate between UC and CD.

Characterization of Monodisperse Aqueous Latex Dispersions Prepared with N-Isopropylacrylamide

Poly-N-isopropylacrylamide (poly-NIPAM) is a water soluble nonionic polymer that exhibits a lower consolute solution temperature (LCST) of about 31°C. This paper describes the preparation and characterization of a monodisperse, hydrophilic polymer latex of poly-NIPAM, crosslinked by N,N'-methylenebisacrylamide. The presence of these crosslinking moieties will prevent dissolution of the particles at low temperatures; rather the particles will be swollen with solvent such that a microgel is formed. The swelling and rheological behaviour of the latex has been studied. The results show that at high temperatures the particles are ˜ 30 nm whilst at 25°C, the particles were ˜ 130 nm in diameter. This four fold increase in the particle diameter correspond to a ˜ sixty fold increase in volume. The rheological properties, both continuous and oscillatory shear, of these systems have also been studied and is strongly temperature dependant, reflecting the changes in phase volume of the NIPAM latex.

Renal medullary carcinoma: sonographic, computed tomography, magnetic resonance and angiographic findings

Renal medullary carcinoma is a recently described, highly aggressive tumour, occurring predominantly in young patients of African descent with sickle cell trait (SCT). All have been metastatic at surgery. Surgery, radiotherapy and chemotherapy do not appear to alter the course of the disease. The survival time is very short. Presentation is usually with haematuria, abdominal pain and weight loss. Forty-nine patients have been reported from the USA, of these 47 were African/Americans. The reports have mostly appeared in pathology journals. On review of the imaging findings reported in the radiological journals, it becomes apparent that it is possible for a radiologist to suggest a specific diagnosis in the appropriate demographic and clinical setting. Here the first British patient of Afro-Caribbean decent in whom a pre-operative diagnosis was suggested on the imaging findings of a centrally located renal pelvic tumour, encasing the pelvis on a background of SCT in a 28-year-old is described. It is expected that a high index of suspicion in the appropriate clinical setting may lead to earlier diagnosis, treatment and survival of patients. The patient is alive and reasonably well 9 months after surgery. The full range of imaging findings in renal medullary carcinoma are described.

A primary intraosseous carcinoma of the anterior maxilla. Report of a new case

The case of a primary intraosseous carcinoma occurring in the maxilla is presented. The classification; clinical, radiologic, and light microscopic features; and treatment are described. These rare lesions should be considered among the diagnostic possibilities when patients present with atypical cysts of the jaws.

Factors influencing GAP-43 gene expression in PC12 pheochromocytoma cells

We have studied factors controlling message levels for the neuronal growth- and plasticity-associated protein, GAP-43. Following exposure of PC12 cells to various effectors, cytoplasmic RNA was isolated and analyzed by Northern transfer and autoradiography using a GAP-43 cDNA probe. Induction by NGF is apparent after 3 hr exposure and reaches maximal levels at 24 hr. Beyond 24 hr, levels remain constant in the continued presence of NGF. Induction is insensitive to variations in culture conditions, such as plating density or substrate, which influence NGF-induced neurite outgrowth. Other inducers, in order of decreasing efficacy, are FGF, dBcAMP, TPA, K+, and EGF. Insulin and retinoic acid are ineffective. Dexamethasone partially inhibited basal expression as well as induction by NGF, FGF, dBcAMP, and TPA. The methyltransferase inhibitor 5'-S-(2-methyl-propyl)adenosine completely inhibited induction by NGF, FGF, and dBcAMP. Inhibition of protein synthesis by cycloheximide partially decreased induction by NGF, FGF, and TPA but slightly enhanced dBcAMP induction. Complete down-regulation of protein kinase C by chronic TPA treatment completely eliminated the TPA response but slightly enhanced induction by NGF. These findings and the results of additivity experiments in which cells were stimulated with various combinations of NGF, dBcAMP and TPA suggest that NGF induction of GAP-43 RNA (1) does not involve activation of protein kinase C but (2) may be mediated partially via activation of protein kinase A.