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

PURPOSE: The cardiopulmonary exercise test (CPET) is a valuable tool to assess cardiopulmonary exercise capacity in pediatric oncology patients after chemotherapy. In addition, few studies on the utility of submaximal testing have been performed, which could be important as some patients are unable to complete a maximal effort test secondary to deconditioning by both disease and treatment. MATERIALS AND METHODS: We performed a retrospective chart review of pediatric cancer patients exposed to chemotherapy from 1992 to 2013 who underwent CPET with cycle ergometry (n=27). The study patients were compared with age-matched, sex-matched, and size-matched normal controls. The submaximal measure recorded was the oxygen consumption (VO2)@respiratory exchange ratio (RER) 1.0 during a maximal effort test. RESULTS: The chemotherapy group demonstrated significantly lower exercise time (9.2±3.6 vs. 11.4±3.8; P=0.008), total work capacity (4914.4±3290.3 vs. 7664.4±4289.5; P=0.004), systolic blood pressure at peak exercise (162.9±23.2 vs. 177.3±23.8; P=0.01), indexed peak VO2 (33.9±6.9 vs. 40.0±6.3; P=0.001), and indexed peak oxygen pulse (6.1±1.3 vs. 7.0±1.5; P=0.004)). For the submaximal outcome measured, 11/27 of the chemotherapy patients had VO2@RER 1.0 values <-2 SD from the mean compared with 0/27 control patients. CONCLUSIONS: Pediatric patients exposed to chemotherapy have impaired cardiopulmonary exercise capacity. The VO2@RER 1.0 in chemotherapy patients suggests that this may be a reliable submaximal measure in this population. IMPLICATIONS FOR CANCER SURVIVORS: This study demonstrates that the CPET can be used in pediatric cancer survivors with prior exposure to chemotherapy to demonstrate impaired cardiopulmonary exercise tolerance, which is demonstrated on submaximal and maximal effort testing.

Cost of Unnecessary Testing in the Evaluation of Pediatric Syncope.

Syncope is a common and a typically benign clinical problem in children and adolescents. The majority of tests ordered in otherwise healthy pediatric patients presenting with syncope have low diagnostic yield. This study quantifies testing and corresponding patient charges in a group of pediatric patients presenting for outpatient evaluation for syncope. Patients seen between 3/2011 and 4/2013 in the multi-disciplinary Syncope Clinic at Cincinnati Children's Hospital Medical Center were enrolled in a registry which was reviewed for patient information. The electronic medical record was used to determine which syncope patients underwent cardiac (electrocardiogram, echocardiogram, or exercise testing) or neurologic (head CT/MRI or electroencephalogram) testing within the interval from 3 months before to 3 months after the Syncope Clinic visit. Testing charges were obtained through hospital billing records. 442 patients were included for analysis; 91% were Caucasian; 65.6% were female; median age was 15.1 years (8.1-21.2 years). Cardiac and neurologic testing was common in this population. While some testing was performed during the Syncope Clinic visit, 46% of the testing occurred before or after the visit. A total of $1.1 million was charged to payers for cardiac and neurological testing with an average total charge of $2488 per patient. Despite the typically benign etiology of pediatric syncope, patients often have expensive and unnecessary cardiac and/or neurologic testing. Reducing or eliminating this unnecessary testing could have a significant impact on healthcare costs, especially as the economics of healthcare shift to more capitated systems.

Endothelial Function and Arterial Stiffness Relate to Functional Outcomes in Adolescent and Young Adult Fontan Survivors.

BACKGROUND: Fontan survivors demonstrate diminished vascular function and functional outcomes, but the relationships between these measures have not been established. METHODS AND RESULTS: We performed a cross-sectional study of 60 Fontan survivors (52% male) with a mean age of 13.9±4.1 years and mean Fontan duration of 9.9±4.2 years. Multimodality assessment of endothelial function (reactive hyperemia index and flow-mediated dilation) and arterial stiffness (augmentation index and baseline pulse amplitude) was performed with peripheral arterial tonometry and brachial flow-mediated dilation. Aerobic capacity was determined using cardiopulmonary exercise testing; mean peak and percentage of predicted oxygen consumption (VO2) were 27.8±7.6 mL/kg per minute and 71.0±21.2%, respectively. Quality of life and physical activity were assessed using the Pediatric Quality of Life Inventory (PedsQL) and the Physical Activity Questionnaire. Vascular measures served as predictor variables, whereas functional measures served as outcome variables. In all cases, worse vascular measures were associated with worse functional measures. Flow-mediated dilation-derived reactive hyperemia index (P<0.05) was positively associated with VO2 at anaerobic threshold. Peripheral arterial tonometry-derived baseline pulse amplitude (P<0.05) was negatively associated with the ratio of minute ventilation to carbon dioxide at anaerobic threshold. Flow-mediated dilation-derived reactive hyperemia index and peripheral arterial tonometry-derived augmentation index (P<0.05) were positively and negatively associated, respectively, with peak VO2. Maximum flow-mediated dilation (P<0.05) was positively associated with Physical Activity Questionnaire score. Peripheral arterial tonometry-derived augmentation index and baseline pulse amplitude (P<0.05) were negatively associated with parent-reported PedsQL total and physical heath summary scores. CONCLUSIONS: Increased arterial stiffness and decreased endothelial function are associated with lower aerobic capacity, physical activity, and quality of life in adolescent and young adult Fontan survivors. Understanding the cause-effect relationship between vascular function and functional outcomes is an important next step.