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

Abstract

Background Late-onset cardiovascular complications are of serious concerns for even asymptomatic pediatric cancer survivors (PCS). We investigated whether cardiopulmonary exercise testing (CPET) can delineate the underlying pathophysiology of preclinical cardiovascular abnormalities in PCS. Methods We examined CPET data via cycle ergometer in asymptomatic PCS with normal echocardiogram and age-matched controls. Peak and submaximal parameters were analyzed. Results 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 watt, 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 DVE/DVCO2) were comparable. Peak respiratory quotient (RQ) was significantly higher in PCS (p = 0.0006). Stroke volume (SV) reserve was decreased in PCS, indicated by simultaneous higher dependency on HR (higher ΔHR/ΔWR) and lower peak oxygen pulse (OP) at the peak exercise. Twelve PCS with high peak RQ (≥ 1.3) revealed lower pVO2 and VAT than the rest of PCS despite higher ventilatory efficiency (lower DVE/DVCO2), suggesting fundamental deficiency in oxygen utilization in some PCS. Conclusions Poor exercise performance in PCS is mainly attributed to limited stroke volume reserve, but the underlying pathophysiology is multi-factorial. Combined assessment of peak and submaximal CPET parameters provided critical information in delineating underlying exercise physiology of PCS. (244 words)

Surveillance cardiopulmonary exercise testing can risk-stratify childhood cancer survivors: who are at risk for long-term cardiovascular complications and why?

“…Poor performers showed signi cantly higher pRER than Good performers in both sexes. We previously showed that signi cantly higher pRER in CCS compared with age-matched healthy controls is due primarily to limited VO2 increase at peak exercise in combination with reduced VAT [17]. Higher pRER in Poor groups may also represent a higher dependency of carbohydrate rather than lipid metabolism during exercise [41], indicating changes in muscle metabolism for energy production.…”

Comprehensive Analysis of Cardiopulmonary Exercise Testing Characterizes Age-Related Exercise Performance in Growing Children and Adolescents

“…Two CPET parameters (including weight) were simultaneously plotted in x and y axis to characterize how age-related growth and functional maturation in uenced the exercise performance. Correlations between weight (kg) and pVO2 (L/min), DHR/DWR and DVO2/DHR, VAT (L/min) and pVO2 (L/min), and pVE (L/min) and pVO2 (L/min) indicate group trends of skeletal muscle effects, stroke volume reserve, exercise endurance beyond AT, and ventilatory e ciency of oxygen uptake, respectively [15][16][17].…”