Comprehensive cardiopulmonary profile of individuals with Down syndrome

BACKGROUND

Individuals with Down syndrome (DS) have low levels of cardiorespiratory fitness and previous studies have shown that these low levels of fitness have a physiological cause. During exercise, the cardiovascular, ventilatory and muscular systems are simultaneously active. While individual parameters of these systems have been investigated in DS before, the interaction between these parameters and systems have not been discussed in detail. Doing so may provide important insight regarding the aetiology of low cardiorespiratory fitness and which parameters of the cardiovascular, pulmonary and muscular systems are altered in individuals with DS compared with their peers without DS.

METHODS

Cardiopulmonary exercise tests were performed in healthy adults with and without DS. Parameters related to the cardiovascular, ventilatory and muscular systems were collected until VO_2peak . In total, 51 participants were included in analysis, of which 21 had DS.

RESULTS

Individuals with DS showed lower peak values for all collected outcomes (P ≤ 0.001) compared with those without DS, except for ventilatory threshold as a percentage of maximal oxygen uptake and V_E /VCO₂ slope, which were similar.

CONCLUSIONS

Our results show that individuals with DS present impairments across the cardiovascular, ventilatory and muscular aspects of the cardiopulmonary system.

Breast cancer survivors with preserved or rescued cardiorespiratory fitness have similar cardiac, pulmonary and muscle function compared to controls

Breast cancer survivors (BCS) have a high prevalence of cardiovascular disease and low cardiorespiratory fitness (CRF). CRF is an important predictor of survival in BCS. However, the physiological factors that contribute to low CRF in BCS have not been completely elucidated. To assess differences in physiological factors (cardiac, pulmonary, muscle function) related to CRF between BCS and controls. Twenty-three BCS and 23 age-body mass index (BMI) matched controls underwent a peak cycling exercise test to determine CRF, with physiological factors measured at resting and at peak exercise. Cardiac hemodynamics (stroke volume [SV], SVindex, heart rate [HR], cardiac output [Formula: see text], and [Formula: see text]index) were evaluated using ultrasonography. Pulmonary function was evaluated using the oxygen uptake efficiency slope (OUES), ventilation to carbon dioxide production slope [Formula: see text] and breathing reserve at peak exercise (BR). Muscle oxygenation variables (oxygenated [HbO₂] deoxygenated [HHb] and total hemoglobin [Hb], and tissue oxygenation index [TSI]) were measured with near-infrared spectroscopy (NIRS). Both groups had similar CRF and similarly increased all hemodynamic variables (HR, SV, SVindex, [Formula: see text] and [Formula: see text]index) at peak exercise compared to resting (p < 0.001). BCS had higher overall HR and lower SVindex (group effect, p < 0.05). BCS had similar OUES, [Formula: see text] and BR compared to the controls. Both groups decreased TSI, and increased Hb and HHb similarly at peak exercise compared to resting (p < 0.001). Our data suggest BCS do not exhibit differences in cardiac, pulmonary, or muscle function at peak exercise compared to controls, when both groups have similar CRF and physical activity.

Alcohol Consumption: A New Risk Factor for Arterial Stiffness?

The relationship between alcohol consumption and cardiovascular disease risk is complex. Low-to-moderate daily alcohol consumption (1–2 drinks/day) is associated with reduced risk, whereas greater amounts of alcohol consumption and a “binge” pattern of drinking are associated with increased cardiovascular risk and mortality. Arterial stiffness may help explain the complex relationship. This integrated review summarizes data from studies examining the associations between alcohol consumption and pulse wave velocity, a gold standard measure of arterial stiffness. We also briefly review the concept and methodology of pulse wave velocity measurement as well as the mechanisms of alcohol-induced arterial stiffening. Findings among the different studies reviewed were inconsistent with methodological challenges related to alcohol use assessment. While making specific conclusions regarding this relationship is tenuous; the data suggest that excessive alcohol consumption or a binge drinking pattern is associated with increased arterial stiffness.

Effect of live-fire training on ventricular-vascular coupling

INTRODUCTION

Cardiovascular events are a leading cause of firefighter duty-related death, with the greatest risk occurring during or shortly after fire suppression activity. Increased cardiovascular risk potentially manifests from detrimental changes in ventricular function, vascular load, and their interaction, described as ventricular-vascular coupling.

PURPOSE

To determine the effect of live-fire training on ventricular-vascular coupling.

METHODS

Sixty-eight male (28 [Formula: see text] 7 years, 26.9 [Formula: see text] 3.9 kg/m²) and fifteen female (36 [Formula: see text] 8 years, 24.3 [Formula: see text] 3.9 kg/m²) firefighters completed hemodynamic and cardiac measures before and after 3 h of intermittent live-fire training. Left ventricular function was assessed as ejection fraction (EF) and ventricular elastance (E_LV: end systolic pressure [ESP]/end systolic volume) via echocardiography and applanation tonometry-estimated ESP. Vascular load was assessed as arterial elastance (E_A: ESP/stroke volume [SV]). Ventricular-vascular coupling (VVC) was quantified as the ratio of E_A to E_LV and indexed to body surface area (E_AI, E_LVI).

RESULTS

Following firefighting EF decreased (p < 0.01) with no change in E_LVI (p = 0.34). SV decreased (p < 0.01) with no change in ESP (p = 0.09), driving a significant increase in E_AI (p < 0.01). These changes resulted in a significant increase in the VVC ratio (p < 0.01).

CONCLUSION

The findings suggest that firefighting does not alter ventricular elastance but increases arterial elastance in healthy firefighters, resulting in a mismatch between ventricular and vascular systems. This increase in ventricular-vascular coupling ratio and concomitant reduction in ventricular systolic function may contribute to increased cardiovascular risk following live firefighting.

Oral vitamin C restores endothelial function during acute inflammation in young and older adults

Oxidative stress has been linked to reductions in vascular function during acute inflammation in young adults; however, the effect of acute inflammation on vascular function with aging is inconclusive. The aim of this study was to determine if oral antioxidant administration eliminates vascular dysfunction during acute inflammation in young and older adults. Brachial flow-mediated dilation (FMD) and carotid-femoral pulse wave velocity (PWV) were measured in nine young (3 male, 24 ± 4 yrs, 26.2 ± 4.9 kg/m2 ) and 16 older (13 male, 64 ± 5 yrs, 25.8 ± 3.2 kg/m2 ) adults before and 2-h after oral consumption of 2 g of vitamin C. The vitamin C protocol was completed at rest and 24 h after acute inflammation was induced via the typhoid vaccine. Venous blood samples were taken to measure markers of inflammation and vitamin C. Both interleukin-6 (Δ+0.7 ± 1.8 pg/ml) and C-reactive protein (Δ+1.9 ± 3.1 mg/L) were increased at 24 h following the vaccine (p < 0.01). There was no change in FMD or PWV following vitamin C administration at rest (p > 0.05). FMD was lower in all groups during acute inflammation (Δ-1.4 ± 1.9%, p < 0.01), with no changes in PWV (Δ-0.0 ± 0.9 m/s, p > 0.05). Vitamin C restored FMD back to initial values in young and older adults during acute inflammation (Δ+1.0 ± 1.8%, p < 0.01) with no change in inflammatory markers or PWV (p > 0.05). In conclusion, oral vitamin C restored endothelial function during acute inflammation in young and older adults, with no effect on aortic stiffness. The effect of vitamin C on endothelial function did not appear to be due to reductions in inflammatory markers. The exact mechanisms should be further investigated.

Impact of acute changes in blood pressure and arterial stiffness on cerebral pulsatile haemodynamics in young and middle-aged adults

NEW FINDINGS

What is the central question of this study? Does cerebrovascular pulsatility respond differently to acute increases in arterial stiffness in middle-aged compared with young adults? What is the main finding and its importance? Compared with young adults, middle-aged adults exhibited similar changes in cerebral pulsatile damping despite attenuated changes in carotid diameter and cerebrovascular pulsatility during blood pressure-dependent, but not blood pressure-independent, increases in large artery stiffness.

ABSTRACT

Acute manipulation of arterial stiffness through interventions that increase sympathetic activity might provoke cerebral pulsatility and damping and reveal whether cerebrovascular haemodynamics respond differently to transient elevations in arterial stiffness in middle-aged compared with young adults. We compared cerebral pulsatility and damping in middle-aged versus young adults during two different sympathetic interventions [cold pressor test (CP) and lower-body negative pressure (LBNP)] that increase arterial stiffness acutely. Cerebrovascular haemodynamics were assessed in 15 middle-aged (54 ± 7 years old; 11 female) and 15 sex-matched young adults (25 ± 4 years old) at rest and during the CP test (4 min, 6.4 ± 0.8°C) and LBNP (6 min, -20 mmHg). Mean blood pressure was measured continuously via finger photoplethysmography. Carotid-femoral pulse wave velocity (cfPWV) and carotid stiffness were measured via tonometry and ultrasound. Blood velocity pulsatility index (PI) was measured at the middle cerebral (MCA) and common carotid artery (CCA) using Doppler, with pulsatile damping calculated as CCA PI divided by MCA PI. Increases in cfPWV were driven by changes in mean pressure during CP but not during LBNP in both groups (P < 0.05). Pulsatile damping decreased in both groups (P < 0.05) despite reductions in MCA PI and greater carotid dilatation during CP in young compared with middle-aged adults (P < 0.05). Pressure-independent increases in cfPWV during LBNP did not alter pulsatile damping but decreased MCA PI in both young and middle-aged adults (P < 0.05). These data suggest that changes in carotid diameter and cerebrovascular pulsatility differ between young and middle-aged adults despite similar changes in cerebral pulsatile damping during blood pressure-dependent, but not blood pressure-independent, increases in large artery stiffness.

Anthropometry does not fully explain low fitness among adults with Down syndrome

BACKGROUND

Cardiorespiratory fitness, expressed as peak oxygen uptake during exercise (VO₂ peak), is an important predictor of cardiovascular health and is related to anthropometry in the general population. Individuals with Down syndrome (DS) have reduced cardiorespiratory fitness and often exhibit different anthropometrics compared with the general population. Interestingly, the relation between anthropometry and cardiorespiratory fitness found in the general population is not apparent in individuals with DS. However, accurate measures with dual energy X-ray absorptiometry (DEXA) scan have not been used to investigate this relationship in this population. The purpose of this paper was to investigate the relationship between accurate measures of anthropometry and cardiorespiratory fitness in adults with DS compared with an age-matched and sex-matched control group.

METHODS

Anthropometrics (height, weight, waist and hip circumference, body composition via DEXA) and cardiorespiratory fitness (VO₂ peak, measured during a graded maximal exercise test) were assessed in adults with (n = 9; 25 ± 3 years; 6 male patients) and without DS (n = 10, 24 ± 4 years; 5 male patients).

RESULTS

Participants with DS were shorter (P < 0.01) than without DS and had a higher body mass index (P < 0.01), waist circumference (WC) (P = 0.026) and waist/height ratio (WHtR) (P < 0.01), but similar weight, body surface area (BSA), waist/hip ratio and body composition (P > 0.05). Participants with DS had significantly lower relative VO₂ peak and VO₂ peak corrected for total lean mass (TLM), but similar absolute VO₂ peak, compared with without DS. In participants with DS, only WC and WHtR were associated with VO₂ peak, whereas in participants without DS, height, weight, BSA, TLM, leg lean mass and body fat percentage were associated with VO₂ peak.

CONCLUSIONS

These results suggest that the relation between anthropometry and cardiorespiratory fitness found in the general population is not the same in adults with DS and that anthropometrics do not fully explain cardiorespiratory fitness in adults with DS. Further research into potential alternative explanations is required.

An early appointment to outpatient cardiac rehabilitation at hospital discharge improves attendance at orientation: a randomized, single-blind, controlled trial

BACKGROUND

Outpatient cardiac rehabilitation (CR) decreases mortality rates but is underutilized. Current median time from hospital discharge to enrollment is 35 days. We hypothesized that an appointment within 10 days would improve attendance at CR orientation.

METHODS AND RESULTS

At hospital discharge, 148 patients with a nonsurgical qualifying diagnosis for CR were randomized to receive a CR orientation appointment either within 10 days (early) or at 35 days (standard). The primary end point was attendance at CR orientation. Secondary outcome measures were attendance at ≥1 exercise session, the total number of exercise sessions attended, completion of CR, and change in exercise training workload while in CR. Average age was 60±12 years; 56% of participants were male and 49% were black, with balanced baseline characteristics between groups. Median time (95% confidence interval) to orientation was 8.5 (7-13) versus 42 (35 to NA [not applicable]) days for the early and standard appointment groups, respectively (P<0.001). Attendance rates at the orientation session were 77% (57/74) versus 59% (44/74) in the early and standard appointment groups, respectively, which demonstrates a significant 18% absolute and 56% relative improvement (relative risk, 1.56; 95% confidence interval, 1.03-2.37; P=0.022). The number needed to treat was 5.7. There was no difference (P>0.05) in any of the secondary outcome measures, but statistical power for these end points was low. Safety analysis demonstrated no difference between groups in CR-related adverse events.

CONCLUSIONS

Early appointments for CR significantly improve attendance at orientation. This simple technique could potentially increase initial CR participation nationwide.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT01596036.