Anita T. Cote

Childhood Obesity and Cardiovascular Dysfunction

Obesity-related cardiovascular disease in children is becoming more prevalent in conjunction with the rise in childhood obesity. Children with obesity are predisposed to an increased risk of cardiovascular morbidity and mortality in adulthood. Importantly, research in children with obesity over the last decade has demonstrated that children may exhibit early signs of cardiovascular dysfunction as a result of their excess adiposity, often independent of other obesity-related comorbidities such as dyslipidemia and insulin resistance. The clinical evidence is accumulating to suggest that the cardiovascular damage, once observed only in adults, is also occurring in obese children. The objective of this review is to provide a synopsis of the current research on cardiovascular abnormalities in children with obesity and highlight the importance and need for early detection and prevention programs to mitigate this potentially serious health problem.

Pulse Decomposition Analysis of the digital arterial pulse during hemorrhage simulation

Background Markers of temporal changes in central blood volume are required to non-invasively detect hemorrhage and the onset of hemorrhagic shock. Recent work suggests that pulse pressure may be such a marker. A new approach to tracking blood pressure, and pulse pressure specifically is presented that is based on a new form of pulse pressure wave analysis called Pulse Decomposition Analysis (PDA). The premise of the PDA model is that the peripheral arterial pressure pulse is a superposition of five individual component pressure pulses, the first of which is due to the left ventricular ejection from the heart while the remaining component pressure pulses are reflections and re-reflections that originate from only two reflection sites within the central arteries. The hypothesis examined here is that the PDA parameter T13, the timing delay between the first and third component pulses, correlates with pulse pressure. T13 was monitored along with blood pressure, as determined by an automatic cuff and another continuous blood pressure monitor, during the course of lower body negative pressure (LBNP) sessions involving four stages, -15 mmHg, -30 mmHg, -45 mmHg, and -60 mmHg, in fifteen subjects (average age: 24.4 years, SD: 3.0 years; average height: 168.6 cm, SD: 8.0 cm; average weight: 64.0 kg, SD: 9.1 kg). Results Statistically significant correlations between T13 and pulse pressure as well as the ability of T13 to resolve the effects of different LBNP stages were established. Experimental T13 values were compared with predictions of the PDA model. These interventions resulted in pulse pressure changes of up to 7.8 mmHg (SE = 3.49 mmHg) as determined by the automatic cuff. Corresponding changes in T13 were a shortening by -72 milliseconds (SE = 4.17 milliseconds). In contrast to the other two methodologies, T13 was able to resolve the effects of the two least negative pressure stages with significance set at p < 0.01. Conclusions The agreement of observations and measurements provides a preliminary validation of the PDA model regarding the origin of the arterial pressure pulse reflections. The proposed physical picture of the PDA model is attractive because it identifies the contributions of distinct reflecting arterial tree components to the peripheral pressure pulse envelope. Since the importance of arterial pressure reflections to cardiovascular health is well known, the PDA pulse analysis could provide, beyond the tracking of blood pressure, an assessment tool of those reflections as well as the health of the sites that give rise to them.

A systematic review of exercise as a therapeutic intervention to improve arterial function in persons living with spinal cord injury

Study design:All randomized controlled trials, prospective cohort, case–controlled, pre–post studies and case reports that assessed exercise interventions, which influence arterial structure and function after spinal cord injury (SCI), were included.Objective:To review systematically the evidence for exercise as a therapy to alter arterial function in persons with SCI.Setting:Literature searches were conducted for appropriate articles using several electronic databases (e.g. MEDLINE, EMBASE).Methods:Three independent reviewers evaluated each investigations quality, using the Physiotherapy Evidence Database Scale for randomized controlled trials and Downs and Black Scale for all other studies. Results were tabulated and levels of evidence assigned.Results:A total of 283 studies were found through the systematic literature search. Upon review of the articles, 27 were included. The articles were separated into those investigating arterial benefits, resulting from either acute bouts of exercise or long-term exercise interventions. The ability of both acute and long-term exercise interventions to improve arterial structure and function in those with SCI was supported by limited to moderate methodological quality. Upper body wheeling is the most commonly examined exercise therapy for improving arterial function. It appears from the evidence that a variety of exercise interventions, including passive exercise, upper body wheeling, functional electrical stimulation and electrically stimulated resistance exercise, can improve arterial function in those living with SCI.Conclusions:Although the quality and volume of evidence is low, the literature supports exercise as a useful intervention technique for improving arterial function in those with SCI.

Aortic stiffness increased in spinal cord injury when matched for physical activity.

PURPOSE The objective of this study is to compare arterial stiffness between those with spinal cord injury (SCI) and able-bodied (AB) individuals when matched for habitual level of physical activity. METHODS A total of 17 SCI and 17 AB individuals were matched for sex, age, weight, blood pressure, and levels of self-reported habitual physical activity (Godin-Shephard). Measures included central pulse wave velocity (PWV) (carotid-femoral PWV (cfPWV)) and lower limb PWV (femoral--toe PWV(ftPWV)) as well as large and small arterial compliance. RESULTS The cfPWV was significantly elevated (7.3 ± 2.1 vs. 5.7 ± 1.4 m·s, P < 0.05) in SCI compared with AB. No other measures of arterial stiffness were different between the groups. Moderate to vigorous physical activity was significantly correlated with both large (r = 0.48, P < 0.05) and small (r = 0.65, P < 0.01) artery compliance, but not cfPWV or ftPWV. CONCLUSIONS Both large and small artery compliance appear to be associated with habitual physical activity in physically active individuals with SCI. However, we did not show that physical activity is associated with PWV in physically active individuals with SCI. These findings suggest that factors other than physical inactivity may mediate the increase in arterial stiffness widely reported in the SCI population.

Obesity and Arterial Stiffness in Children Systematic Review and Meta-Analysis

Objective— Childhood obesity is associated with risk factors for cardiovascular disease. Arterial stiffness is considered one of the earliest detectable measures of vascular damage. There is controversy in the literature regarding the effects of childhood obesity on arterial stiffness. The objective of this study is to systematically review the literature and to conduct a meta-analysis comparing measures of central arterial stiffness in children and adolescents with obesity to healthy body mass index controls. Approach and Results— Literature searches were conducted using databases (eg, MEDLINE, EMBASE) and citations cross-referenced. Studies assessing central pulse wave velocity or β-stiffness index were included. A random effects meta-analysis of the standardized mean difference and 95% confidence intervals in arterial stiffness between children with obesity and control children was performed for each arterial stiffness measure. A total of 523 studies were identified. Fifteen case–control studies were included, with 2237 children/adolescents (1281 with obesity, 956 healthy body mass index controls) between 5 and 24 years of age. All studies measuring carotid and aortic β-stiffness index and 10/12 studies measuring central pulse wave velocity reported greater arterial stiffness in children/adolescents with obesity compared with controls. A random effects meta-analysis was performed revealing a significant effect of obesity on pulse wave velocity (standardized mean difference=0.718; 95% confidence interval=0.291–1.415), carotid β-stiffness index (0.862; 0.323–1.402), and aortic β stiffness index (1.017; 0.419–1.615). Conclusion— These findings indicate that child/adolescent obesity is associated with greater arterial stiffness. However, further research is needed to address confounders, such as pubertal status, that may affect this relationship in children. In the future, these techniques may be useful in risk stratification and guiding clinical management of obese children to optimize cardiovascular outcomes. # Significance {#article-title-50}Objective— Childhood obesity is associated with risk factors for cardiovascular disease. Arterial stiffness is considered one of the earliest detectable measures of vascular damage. There is controversy in the literature regarding the effects of childhood obesity on arterial stiffness. The objective of this study is to systematically review the literature and to conduct a meta-analysis comparing measures of central arterial stiffness in children and adolescents with obesity to healthy body mass index controls. Approach and Results— Literature searches were conducted using databases (eg, MEDLINE, EMBASE) and citations cross-referenced. Studies assessing central pulse wave velocity or &bgr;-stiffness index were included. A random effects meta-analysis of the standardized mean difference and 95% confidence intervals in arterial stiffness between children with obesity and control children was performed for each arterial stiffness measure. A total of 523 studies were identified. Fifteen case–control studies were included, with 2237 children/adolescents (1281 with obesity, 956 healthy body mass index controls) between 5 and 24 years of age. All studies measuring carotid and aortic &bgr;-stiffness index and 10/12 studies measuring central pulse wave velocity reported greater arterial stiffness in children/adolescents with obesity compared with controls. A random effects meta-analysis was performed revealing a significant effect of obesity on pulse wave velocity (standardized mean difference=0.718; 95% confidence interval=0.291–1.415), carotid &bgr;-stiffness index (0.862; 0.323–1.402), and aortic &bgr; stiffness index (1.017; 0.419–1.615). Conclusion— These findings indicate that child/adolescent obesity is associated with greater arterial stiffness. However, further research is needed to address confounders, such as pubertal status, that may affect this relationship in children. In the future, these techniques may be useful in risk stratification and guiding clinical management of obese children to optimize cardiovascular outcomes.

Obesity and Arterial Stiffness in Children

Objective— Childhood obesity is associated with risk factors for cardiovascular disease. Arterial stiffness is considered one of the earliest detectable measures of vascular damage. There is controversy in the literature regarding the effects of childhood obesity on arterial stiffness. The objective of this study is to systematically review the literature and to conduct a meta-analysis comparing measures of central arterial stiffness in children and adolescents with obesity to healthy body mass index controls. Approach and Results— Literature searches were conducted using databases (eg, MEDLINE, EMBASE) and citations cross-referenced. Studies assessing central pulse wave velocity or β-stiffness index were included. A random effects meta-analysis of the standardized mean difference and 95% confidence intervals in arterial stiffness between children with obesity and control children was performed for each arterial stiffness measure. A total of 523 studies were identified. Fifteen case–control studies were included, with 2237 children/adolescents (1281 with obesity, 956 healthy body mass index controls) between 5 and 24 years of age. All studies measuring carotid and aortic β-stiffness index and 10/12 studies measuring central pulse wave velocity reported greater arterial stiffness in children/adolescents with obesity compared with controls. A random effects meta-analysis was performed revealing a significant effect of obesity on pulse wave velocity (standardized mean difference=0.718; 95% confidence interval=0.291–1.415), carotid β-stiffness index (0.862; 0.323–1.402), and aortic β stiffness index (1.017; 0.419–1.615). Conclusion— These findings indicate that child/adolescent obesity is associated with greater arterial stiffness. However, further research is needed to address confounders, such as pubertal status, that may affect this relationship in children. In the future, these techniques may be useful in risk stratification and guiding clinical management of obese children to optimize cardiovascular outcomes. # Significance {#article-title-50}Objective— Childhood obesity is associated with risk factors for cardiovascular disease. Arterial stiffness is considered one of the earliest detectable measures of vascular damage. There is controversy in the literature regarding the effects of childhood obesity on arterial stiffness. The objective of this study is to systematically review the literature and to conduct a meta-analysis comparing measures of central arterial stiffness in children and adolescents with obesity to healthy body mass index controls. Approach and Results— Literature searches were conducted using databases (eg, MEDLINE, EMBASE) and citations cross-referenced. Studies assessing central pulse wave velocity or &bgr;-stiffness index were included. A random effects meta-analysis of the standardized mean difference and 95% confidence intervals in arterial stiffness between children with obesity and control children was performed for each arterial stiffness measure. A total of 523 studies were identified. Fifteen case–control studies were included, with 2237 children/adolescents (1281 with obesity, 956 healthy body mass index controls) between 5 and 24 years of age. All studies measuring carotid and aortic &bgr;-stiffness index and 10/12 studies measuring central pulse wave velocity reported greater arterial stiffness in children/adolescents with obesity compared with controls. A random effects meta-analysis was performed revealing a significant effect of obesity on pulse wave velocity (standardized mean difference=0.718; 95% confidence interval=0.291–1.415), carotid &bgr;-stiffness index (0.862; 0.323–1.402), and aortic &bgr; stiffness index (1.017; 0.419–1.615). Conclusion— These findings indicate that child/adolescent obesity is associated with greater arterial stiffness. However, further research is needed to address confounders, such as pubertal status, that may affect this relationship in children. In the future, these techniques may be useful in risk stratification and guiding clinical management of obese children to optimize cardiovascular outcomes.

Increased Central Arterial Stiffness Explains Baroreflex Dysfunction in Spinal Cord Injury

After cervical spinal cord injury (SCI), orthostatic hypotension and intolerance commonly ensue. The cardiovagal baroreflex plays an important role in the acute regulation of blood pressure (BP) and is associated with the onset of presyncope. The cardiovagal baroreflex is dysfunctional after SCI; however, this may be influenced by either increased stiffening of the arteries containing the stretch-receptors (which has been shown in SCI) or a more downstream neural mechanism (i.e., solitary nucleus, sinoatrial node). Identifying where along this pathway baroreflex dysfunction occurs may highlight a potential therapeutic target. This study examined the relationship between spontaneous cardiovagal baroreflex sensitivity (BRS) and common carotid artery (CCA) stiffness in those with high level SCI before and after midodrine (alpha1-agonist) administration, as well as in able-bodied controls, to evaluate: (1) the role arterial stiffening plays mediating baroreflex function after SCI and (2) the effect of normalizing BP on these parameters. Three to five min recordings of beat-by-beat BP and heart rate, as well as 30 sec duration recordings of CCA diameter were used for analysis. All participants were tested supine and during upright-tilt. Arterial stiffness (β-stiffness index) was elevated in those with SCI when upright (+12%; p<0.05). Further, β-stiffness index was negatively related to reduced BRS in those with SCI when upright (R2=0.55; p<0.05), but not in able-bodied persons. Normalizing BP did not improve BRS or CCA stiffness. This study clearly shows that reduced BRS is closely related to increased arterial stiffness in the population with SCI.

Left ventricular mechanics and arterial-ventricular coupling following high-intensity interval exercise

High-intensity exercise induces marked physiological stress affecting the secretion of catecholamines. Sustained elevations in catecholamines are thought to desensitize cardiac beta receptors and may be a possible mechanism in impaired cardiac function following strenuous exercise. In addition, attenuated arterial-ventricular coupling may identify vascular mechanisms in connection with postexercise attenuations in ventricular function. Thirty-nine normally active (NA) and endurance-trained (ET) men and women completed an echocardiographic evaluation of left ventricular function before and after an acute bout of high-intensity interval exercise (15 bouts of 1:2 min work:recovery cycling: 100% peak power output and 50 W, respectively). Following exercise, time to peak twist and peak untwisting velocity were delayed (P < 0.01) but did not differ by sex or training status. Interactions for sex and condition (rest vs. exercise) were found for longitudinal diastolic strain rate (men, 1.46 ± 0.19 to 1.28 ± 0.23 s(-1) vs. women, 1.62 ± 0.25 to 1.63 ± 0.26 s(-1); P = 0.01) and arterial elastance (men 2.20 ± 0.65 to 3.24 ± 1.02 mmHg · ml(-1) · m(-2) vs. women 2.51 ± 0.61 to 2.93 ± 0.68 mmHg · ml(-1) · m(-2); P = 0.04). No cardiac variables were found associated with catecholamine levels. The change in twist mechanics was associated with baseline aortic pulse-wave velocity (r(2) = 0.27, P = 0.001). We conclude that males display greater reductions in contractility in response to high-intensity interval exercise, independent of catecholamine concentrations. Furthermore, a novel association of arterial stiffness and twist mechanics following high-intensity acute exercise illustrates the influence of vascular integrity on cardiac mechanics.

Systemic arterial compliance following ultra-marathon.

There is a growing interest in training for and competing in race distances that exceed the marathon; however, little is known regarding the vascular effects of participation in such prolonged events, which last multiple consecutive hours. There exists some evidence that cardiovascular function may be impaired following extreme prolonged exercise, but at present, only cardiac function has been specifically examined following exposure to this nature of exercise. The primary purpose of this study was to characterize the acute effects of participation in an ultra-marathon on resting systemic arterial compliance. Arterial compliance and various resting cardiovascular indices were collected at rest from 26 healthy ultra-marathon competitors using applanation tonometry (HDI CR-2000) before and after participation in a mountain trail running foot race ranging from 120-195 km which required between 20-40 continuous hours (31.2±6.8 h) to complete. There was no significant change in small artery compliance from baseline to post race follow-up (8.5±3.4-7.7±8.2 mL/mmHgx100, p=0.65), but large artery compliance decreased from 16.1±4.4 to 13.5±3.8 mL/mmHgx10 (p=0.003). Participation in extreme endurance exercise of prolonged duration was associated with acute reductions in large artery compliance, but the time course of this effect remains to be elucidated.

Childhood Obesity, Arterial Stiffness, and Prevalence and Treatment of Hypertension

Opinion statementChildhood obesity is associated with progressive vascular dysfunction as manifest by arterial stiffness and elevated blood pressure with associated subsequent morbidity and mortality because of early cardiovascular events including myocardial infarction and stroke in adulthood. Consequently, the recent dramatic increases in childhood obesity around the world present a hitherto unforeseen public health concern. While coordinated primary prevention efforts remain an ongoing important focus of action, identification and treatment of modifiable cardiovascular risk factors in pediatric patients is necessary given the existing burden of disease and future health consequences. Lifestyle interventions remain a cornerstone of our therapeutic approach, however, medical therapy is needed in some cases and should not be underutilized based on patient age. Herein, we discuss the relationship between childhood obesity and hypertension with a key emphasis on the evolution of adaptive and maladaptive vascular changes in the genesis of overt cardiovascular disease.