New kids on the CPET: age-appropriate outdoor cardiopulmonary exercise testing in preschoolers

Purpose Cardiopulmonary exercise testing (CPET) in preschoolers (4–6 years) represents a challenge. Most studies investigating CPET have been limited to older children (> 8 year). However, knowledge of the performance of small children is essential for evaluating their cardiorespiratory fitness. This study strives to compare a modified Bruce protocol with a new age-appropriate incremental CPET during natural movement running outdoors, using a mobile device. Methods A group of 22 4–6-year-old healthy children was tested indoor on a treadmill (TM) using the modified Bruce protocol. The results were compared with a self-paced incremental running test, using a mobile CPET device in an outdoor park. The speeds were described as (1) slow walking, (2) slow running, (3) regular running, and (4) running with full speed as long as possible. Results Mean exercise time outdoors (6,57 min) was significantly shorter than on the treadmill (11,20 min), $$\dot{V}{O}_{2peak}$$ V ˙ O 2 p e a k (51.1 ml/min/kg vs. 40.1 ml/min/kg), RER (1.1 vs. 0.98) and important CPET parameters such as $$\dot{V}E$$ V ˙ E max, O2pulse, heart rate and breath rate were significantly higher outdoors. The submaximal parameter OUES was comparable between both the tests. Conclusions Testing very young children with a mobile device is a new alternative to treadmill testing. With a significantly shorter test duration, significantly higher values for almost all cardiopulmonary variables can be achieved without losing the ability to determine VT1 and VT2. It avoids common treadmill problems and allows for individualized exercise testing. The aim is to standardize exercise times with individual protocols instead of standardizing protocols with individual exercise times, allowing for better comparability.

Normative blood pressure response to exercise stress testing in children and adolescents

ObjectiveTo describe normative values for blood pressure (BP) response to maximal exercise in children/adolescents undergoing a treadmill stress test.MethodsFrom a retrospective analysis of medical records, patients who had undergone a Bruce protocol exercise stress test, with (1) normal cardiovascular system and (2) a body mass index percentile rank below 95% were included for analysis. Sex, age, height, weight, resting and peak heart rate, resting and peak systolic blood pressure (SBP), test duration, stage of Bruce protocol at termination, reason for undergoing the test and reason for termination of test were collected. Percentiles for exercise-induced changes in SBP were constructed by age and height for each sex with the use of quantile regression models.Results648 patients with a median age of 12.4 years (range 6–18 years) were included. Typical indications for stress testing were investigation of potential rhythm abnormalities, syncope/dizziness and chest pain and were deemed healthy by an overseeing cardiologist. Mean test duration was 12.6±2.2 min. Reference percentiles for change in SBP by sex, age and height are presented.ConclusionThe presented reference percentiles for the change in SBP for normal children and adolescents will have utility for detecting abnormally high or low BP responses to exercise in these age groups.

Predictors of deterioration in cardiorespiratory fitness among healthy adults: the importance of sex and obesity

Introduction Cardiorespiratory fitness (CRF) is associated with cardiovascular co-morbidities and is a strong predictor of adverse cardiovascular outcomes. However, data on the natural history of cardiorespiratory fitness among healthy subjects is limited. Purpose This study investigated what are the predictors of deterioration in CRF over time. Methods We investigated 36,239 men and women who were annually screened in a tertiary medical center and completed an exercise stress test in all visits, with a total of 175,596 annual visits. Subjects who failed to complete maximal exercise stress test according to the Bruce protocol at their first baseline visit were excluded. In addition, subjects with less than five visits to the center or those who developed ischemic heart disease during follow-up were excluded. Fitness was categorized into age- and sex-specific quintiles (Q) according to Bruce protocol treadmill time. Change in CRF between the first baseline visit and the fifth visit was used to calculate fitness deterioration. The primary study endpoint was defined as the lower sex-specific quintile of change in metabolic equivalents (METS) between visits 1 and 5. Logistic regression models were applied. Results Final study population included 10,841 subjects. The mean age of the study population was 49±10 years, the mean BMI was 26±4, and 8107 (75%) were men. Median METS at baseline were 10.8 (IQR 9–12.6) and 11.1 (IQR 9.4–13) at the first and fifth visit, respectively (p<0.001 for METS between visits). Overall, 2189 (20%) subjects met the study endpoint. CFR deterioration was higher among women as compared to men (p=0.023). Out of obesity, hypertension, fasting blood glucose, LDL, and HDL cholesterol, after adjustments for age, sex, and baseline CFR, only obesity was independently associated with fitness deterioration in the multivariate model (OR=1.4 95% CI 1.2–1.5, p<0.001). The association of obesity with fitness deterioration was modified by sex such that the risk of CRF deterioration was more pronounced in women (OR=1.6 95% CI 1.3–2, p<0.001) than in men (OR=1.3 95% CI 1.1–1.4, p<0.001). Conclusion Obesity is an independent predictor of future CRF deterioration. The effect of obesity on future CRF deterioration is more pronounced among women as compared to men. FUNDunding Acknowledgement Type of funding sources: None.

Impact of peak respiratory exchange ratio on the prognostic power of symptoms-limited exercise testing using Bruce protocol in patients with Fontan physiology

Objectives: We evaluated the impact of peak respiratory exchange ratio on the prognostic values of cardiopulmonary exercise variables during symptoms-limited incremental exercise tests in patients with Fontan physiology. Methods: Retrospective single-centre chart review study of Fontan patients who underwent exercise testing using the Bruce protocol between 2014 and 2018 and follow-up. Results: A total of 34 patients (age > 18 years) had a Borg score of ≥7 on the Borg 10-point scale, but only 50% of patients achieved a peak respiratory exchange ratio of ≥ 1.10 (maximal test). Peak oxygen consumption, percent-predicted peak oxygen consumption, and peak oxygen consumption at the ventilatory threshold was reduced significantly in patients with a peak respiratory exchange ratio of < 1.10. Peak oxygen consumption and percent-predicted peak oxygen consumption was positively correlated with peak respiratory exchange ratio values (r = 0.356, p = 0.039). After a median follow-up of 21 months, cardiac-related events occurred in 16 (47%) patients, with no proportional differences in patients due to their respiratory exchange ratio (odds ratio, 0.62; 95% CI: 0.18–2.58; p = 0.492). Multivariate Cox proportional hazard analysis showed percent-predicted peak oxygen consumption, peak heart rate, and the oxygen uptake efficient slope were highly related to the occurrence of events in patients only with a peak respiratory exchange ratio of ≥ 1.10. Conclusions: The value of peak cardiopulmonary exercise variables is limited for the determination of prognosis and assessment of interventions in Fontan patients with sub-maximal effort. Our findings deserve further research and clinical application.

Peak Responses during Exercise Treadmill Testing using Individualized Ramp Protocol and Modified Bruce Protocol in Elderly Patients

Background: Exercise capacity is well known to be an important prognostic factor in patients with cardiovascular disease and among healthy persons. &nbsp; Aim: To determine if there are any differences between the peak exercise response during exercise treadmill testing with the individualized ramp protocol and the modified Bruce protocol in elderly patients. &nbsp; Materials and methods: The study included 40 patients (both male and female), aged 70 years and older, who had not had a baseline history of the confirmed coronary artery disease or heart failure diagnoses. All patients underwent exercise treadmill testing using modified Bruce protocol and individualized ramp protocol for 2 consecutive days. Peak heart rate, peak systolic and diastolic blood pressure, peak pressure-rate double product, exercise duration, and peak metabolic equivalents were recorded in both tests. Perceived level of exertion was evaluated using the Borg 10-point scale. &nbsp; Results: The average duration of exercise was longer for the ramp protocol than for the modified Bruce protocol. When the modified Bruce protocol was used, patients achieved a lower workload than they did in using the ramp protocol. The rating of perceived exertion using the revised Borg scale (0 to 10) was 5.6&plusmn;1.4 for the ramp protocol and 8.7&plusmn;1.4 for the modified Bruce protocol, which indicates that the patients found the ramp protocol easier. &nbsp; Conclusion: In elderly patients the individualized ramp treadmill protocol allows to achieve the optimal test duration with higher degrees of workload and greater patient comfort during the test more often than does the modified Bruce protocol.

Can the Forward-Step-Down Test Be Used Reliably in the Clinical Setting to Assess Movement Changes Resulting from Maximal Exertion? A Pilot Study

Introduction: Visual assessment of lower extremity mechanics is used frequently in clinical practice, and objective scoring of the visual assessment is beneficial to improve objectivity of patient evaluation. In addition, lower extremity mechanics change with fatigue and these changes may increase the risk of lower extremity injury. The Forward-Step-Down Test (FSDT) is one such objective tool, but its ability to detect changes in movement quality in response to exertion are not known. Methods: This study utilized a repeated-measures design, where the participants were scored on the FSDT before performing the Bruce protocol for an exertion stimulus. The participants were re-scored on the FSDT at one, five, and ten minutes after completing the Bruce protocol. Results: Wilcoxon signed-rank tests showed a significant change in FSDT score between baseline and five minutes post-exertion (a< .017). Friedman’s ANOVA was non-significant across all four assessments. In addition, despite testing healthy young adults, 50% of participants scored as “poor” movement quality on the initial test. This number increased to 75% at significant five-minute post-exertion mark. Discussion: Median scores on the FSDT were significantly different at five minutes post-exertion. However, this statistically significant change is of questionable clinical relevance because the median score changed by 0.5. This small change from 3.5 to 4.0 may not represent a change in overall movement quality from “moderate” to “poor.” Results do indicate that the participants in this study overall had poorer than expected movement quality throughout the testing. These results suggest larger data collection and analysis may be warranted for this population and the general population prior to partaking in exercise. Conclusion: The FSDT detects changes in lower extremity mechanics five minutes following a single exertion stimulus. Participants’ scores returned to baseline by ten minutes post-exertion. The FSDT may be a viable tool to assess changes in lower extremity movement quality following a single bout of exertion, and may help determine when participants have recovered back to baseline movement quality.

P626Higher fitness is associated with improved survival among cancer patients

Background Cardio-respiratory fitness (CRF) is a known predictor of cardiovascular morbidity and mortality. However, data on the association of CRF with survival following a diagnosis of cancer is limited. Purpose To evaluate the association between CRF in a large cohort of asymptomatic adults and a probability of survival after subsequent cancer diagnosis. Methods We evaluated asymptomatic self-referred adults aged 40–79 years who were screened annually at a tertiary medical center. All subjects were free of cardiovascular disease and cancer at baseline and completed maximal exercise stress test according to the Bruce protocol. Fitness was categorized into age- and sex-specific quintiles (Q) according to Bruce protocol treadmill time with Q1-Q2 defined as low fitness and Q3-Q5 as higher fitness. Cancer data was available from a national cancer registry. The primary end point was all-cause mortality. Results Final study population in included 15,800 subjects. Mean age was 51±8 years and 72% were men. During median follow up of 13 years (IQR 7–16) 1,312 (8%) subjects developed cancer and 486 (3%) died. Most common cancer types were prostate in 302 (23%) and breast cancer in 189 (14%) patients. No difference was found in distribution of major cancer types between different fitness categories. Univariate Cox regression with cancer as a time dependent covariate showed that subjects who developed cancer during follow up were 19 times more likely to die (95% CI 15.5–22.5, p<0.001). Kaplan Meier analysis showed that the cumulative probability of death from the time of cancer diagnosis was significantly lower among high fitness patients (34% ± 4% vs. 25% ± 3%, p Log rank = 0.008; Figure 1). Multivariate interaction analysis with cancer as a time dependent covariate showed that cancer-related risk of death was fitness-dependent, such that in the lower fitness group cancer was associated with 18 folds increased risk of death (95% CI: 13.5–23) whereas among high fitness group the risk of death was lower (HR=13; 95% CI: 10–17; p for interaction = 0.048). Conclusions Low CRF is associated with worse survival among subjects diagnosed as having cancer during follow up. These findings support the effectiveness of fitness assessment in preventive health care settings.