Cardiopulmonary Aerobic Fitness Assessment During Maximal and Submaximal Exercise Testing in Pediatric Oncology Patients After Chemotherapy

Evaluation of Metabolic and Cardiovascular Risk Measured by Laboratory Biomarkers and Cardiopulmonary Exercise Test in Children and Adolescents Recovered from Brain Tumors: The CARMEP Study

In recent decades, the improvement of treatments and the adoption of therapeutic protocols of international cooperation has led to an improvement in the survival of children affected by brain tumors. However, in parallel with the increase in survival, long-term side effects related to treatments have been observed over time, including the activation of chronic inflammatory processes and metabolic alterations, which can facilitate the onset of metabolic syndrome and increased cardiovascular risk. The aim of this study was to find possible statistically significant differences in the serum concentrations of early biomarkers of metabolic syndrome and in the results of cardiopulmonary exercise testing between survivors of childhood brain tumors and healthy controls. This is a prospective and observational study conducted on a group of 14 male patients who survived childhood brain tumors compared with the same number of healthy controls. The concentrations of early metabolic syndrome biomarkers [adiponectin, leptin, TNF-α, IL-1, IL-6, IL-10, endothelin-1, apolipoprotein B, and lipoprotein (a)] were measured and a cardiopulmonary exercise test (CPET) was performed. Results: Childhood brain tumor survivors performed worse on average than controls on the CPET. Furthermore, they showed higher endothelin-1 values than controls (p = 0.025). The CPET results showed an inverse correlation with leptin. The differences found highlight the greater cardiovascular risk of brain tumor survivors, and radiotherapy could be implicated in the genesis of this greater cardiovascular risk.

Surveillance cardiopulmonary exercise testing can risk-stratify childhood cancer survivors: underlying pathophysiology of poor exercise performance and possible room for improvement

BACKGROUND

Asymptomatic childhood cancer survivors (CCS) frequently show decreased exercise performance. Poor exercise performance may indicate impaired future cardiovascular health.

METHODS

Cardiopulmonary exercise testing (CPET) was performed in asymptomatic off-treatment CCS (age ≥ 10 years). Patients were divided into Normal and Poor performance groups by %predicted maximum VO2 at 80%. Both peak and submaximal CPET values were analyzed.

RESULTS

Thirty-eight males (19 Normal, 19 Poor) and 40 females (18 Normal, 22 Poor) were studied. Total anthracycline dosage was comparable among 4 groups. The body mass index (BMI), although normal, and weight were significantly higher in Poor groups. Peak heart rate (HR) and peak respiratory exchange ratio (RER) were comparable in all four groups. Peak work rate (pWR)/kg, peak oxygen consumption (pVO2)/kg, peak oxygen pulse (pOP)/kg, and ventilatory anaerobic threshold (VAT)/kg were significantly lower, whereas heart rate (HR) increase by WR/kg (ΔHR/Δ[WR/kg] was significantly higher in Poor groups. Simultaneously plotting of weight & pVO2 and ΔHR/ΔWR & ΔVO2/ΔHR revealed a distinct difference between the Normal and Poor groups in both sexes, suggesting decreased skeletal muscle mass and decreased stroke volume reserve, respectively, in Poor CCS. The relationship between VAT and pVO2 was almost identical between the two groups in both sexes. Ventilatory efficiency was mildly diminished in the Poor groups.

CONCLUSIONS

Decreased skeletal muscle mass, decreased stroke volume reserve, and slightly decreased ventilatory efficiency characterize Poor CCS in both sexes. This unique combined CPET analysis provides useful clinical biomarkers to screen subclinical cardiovascular abnormality in CCS and identifies an area for improvement.

Cardiopulmonary Exercise Testing Characterizes Silent Cardiovascular Abnormalities in Asymptomatic Pediatric Cancer Survivors

Late-onset cardiovascular complications are serious concerns for pediatric cancer survivors (PCS) including those who are asymptomatic. We investigated whether cardiopulmonary exercise testing (CPET) can delineate the underlying pathophysiology of preclinical cardiovascular abnormalities in PCS. We examined CPET data via cycle ergometer in asymptomatic PCS with normal echocardiogram and age-matched controls. Peak and submaximal parameters were analyzed. Fifty-three PCS and 60 controls were studied. Peak oxygen consumption (VO₂), peak work rate (WR), and ventilatory anaerobic threshold (VAT) were significantly lower in PCS than controls (1.86 ± 0.53 vs. 2.23 ± 0.61 L/min, 125 ± 45 vs. 154 ± 46 W, and 1.20 ± 0.35 vs. 1.42 ± 0.43 L/min, respectively; all p < 0.01), whereas peak heart rate (HR) and ventilatory efficiency (a slope of minute ventilation over CO₂ production or ∆VE/∆VCO₂) were comparable. Peak respiratory exchange ratio (RER) was significantly higher in PCS (p = 0.0006). Stroke volume (SV) reserve was decreased in PCS, indicated by simultaneous higher dependency on HR (higher ∆HR/∆WR) and lower peak oxygen pulse (OP). Twelve PCS with high peak RER (≥ 1.3) revealed lower pVO₂ and VAT than the rest of PCS despite higher ventilatory efficiency (lower ∆VE/∆VCO₂), suggesting fundamental deficiency in oxygen utilization in some PCS. Poor exercise performance in PCS may be mainly attributed to limited stroke volume reserve, but the underlying pathophysiology is multifactorial. Combined assessment of peak and submaximal CPET parameters provided critical information in delineating underlying exercise physiology of PCS.

Abnormal maximal and submaximal cardiopulmonary exercise capacity in pediatric stem cell transplant recipients despite normal standard echocardiographic parameters: a pilot study

BACKGROUND

Left ventricular systolic dysfunction is a known complication of stem cell transplant (SCT). There has been minimal research to determine if subclinical cardiac dysfunction exists in SCT patients utilizing tools other than standard echocardiography, such as maximal and submaximal effort cardiopulmonary exercise testing (CPET) and vascular function studies.

OBJECTIVE

The objective of this study was to determine the rate of subclinical cardiac dysfunction in patients with normal ejection fraction after SCT, identified by abnormal values by CPET, tissue-Doppler imaging, and arterial stiffness measurements and to further describe submaximal exercise test measures in this population.

STUDY DESIGN

A prospective cohort study of SCT survivors who were at least three years post-SCT without prior anthracycline or radiation exposure and with preserved systolic function (LV ejection fraction > 50%) was performed to evaluate for abnormalities in exercise, vascular function, and diastolic function in an effort to detect subclinical dysfunction in SCT patients.

RESULTS

There were 11 patients (12.4±3.8-years-old) included in the study. No patients had diastolic dysfunction. All patients completed a maximal effort exercise test, and 73% (8/11) had abnormal peak oxygen consumption (VO₂peak), which is a measure of aerobic fitness. However, during submaximal effort CPET, 45% (5/11) had an abnormal VO₂ at anaerobic threshold (i.e. the point in exercise where aerobic transitions to anaerobic metabolism and fatigue starts), and 64% (7/11) had an abnormal oxygen uptake efficiency slope (a measure that relates VO₂peak to total ventilation). 86% (6/7) of the patients with an abnormal oxygen uptake efficiency slope ultimately had an abnormal VO₂peak. There were no vascular function abnormalities.

CONCLUSION

Pediatric survivors of SCT often have abnormal maximal and submaximal exercise capacity without vascular or cardiac dysfunction.

Maximal cardiopulmonary exercise testing in childhood acute lymphoblastic leukemia survivors exposed to chemotherapy

PURPOSE

The purpose of this study was to demonstrate if childhood acute lymphoblastic leukemia (ALL) survivors exposed to chemotherapy (i.e., doxorubicin) are able to achieve a safe maximal cardiopulmonary exercise test (CPET).

METHODS

A total of 250 childhood ALL survivors were eligible to undergo a CPET on ergocycle. Analyses were performed in 216 survivors and stratified in regard to their prognostic risk groups: 99 survivors (55 males and 44 females) at standard risk and 117 survivors (56 males and 61 females) at high risk.

RESULTS

Results showed that 100% (n = 216) of survivors completed a maximal CPET confirmed by the achievement of two out of three of the following criteria: 197 survivors (91.2%) reached a peak RER value of ≥ 1.15, 197 survivors (91.2%) reached a RPE score > 7, and 210 survivors (97.2%) reached a maximal heart rate ≥ 85% of the predicted value. Linear regression analysis showed a significant association between the survivors' cumulative dose of doxorubicin and their VO₂ peak measured. Two non-fatal adverse events were observed and reported at the end of the maximal CPET, while non-fatal adverse events were reported in 5 survivors during the recovery period. None of these events resulted in a long-term complication.

CONCLUSION

Childhood ALL survivors with prior exposure to chemotherapy can achieve a safe maximal CPET. They were able of achieving a maximal exercise test without being limited by symptoms, potential overprotection, or musculoskeletal issues. Thus, it should be the norm to realize a CPET prior a physical activity program to propose an optimal prescription. This study provides important information regarding the maximal physiological parameters that childhood ALL survivors are able to reach and have important clinical implications in the exercise and oncology field for this population of survivors.

Abnormal submaximal cardiopulmonary exercise parameters predict impaired peak exercise performance in sickle cell anemia patients

PURPOSE

Sickle cell anemia (SCA) patients frequently have many comorbidities, including diastolic dysfunction (DD) and exercise intolerance. SCA patients often cannot reach maximal effort on exercise testing; little is known regarding whether submaximal exercise parameters can predict abnormal maximal exercise results in SCA patients and if there are any possible associations with DD.

METHODS

A prospective longitudinal study was performed in SCA patients. All patients had a resting cardiac MRI (CMR), cardiopulmonary exercise test (CPET) with cycle ergometry using a ramp protocol, and an echocardiogram. Exercise data were compared with age-, gender-, and size-matched normal controls.

RESULTS

Compared with normal controls, the SCA group (n = 19) had lower mean max oxygen consumption (VO₂ ; 1378 ± 412 mL/min vs 2237 ± 580, P < 0.01) and workload (117 ± 37.6 watts vs 175 ± 50.5 watts, P = 0.0003). When evaluating the submaximal exercise parameters, there was lower VO₂ at the anaerobic threshold (AT; 950 ± 311.7 vs 1460 ± 409.9, P < 0.01) and oxygen uptake efficiency slope (OUES) at AT (1512 ± 426.2 vs 2080 ± 339, P < 0.01). The max VO₂ strongly correlated with VO₂ at AT (r = 0.9, P < 0.01) and OUES (r = 0.83, P < 0.01) at AT. The VO₂ at AT correlated with hematocrit (r = 0.77, P < 0.05). The OUES correlated with left ventricular ejection fraction by CMR (r = 0.55, P = 0.01), hematocrit (r = 0.52, P = 0.02), and lateral E/e' (r = -0.54, P = 0.01).

CONCLUSIONS

SCA patients have abnormal submaximal exercise measures compared with controls, which is strongly associated with abnormal maximal exercise results. The degree of submaximal abnormality correlates with DD abnormalities by echocardiography. These data expand the scope of functional cardiovascular abnormalities in SCA.