Association of Blood Pressure-Related Increase in Vascular Stiffness on Other Measures of Target Organ Damage in Youth.

BACKGROUND: Hypertension-related increased arterial stiffness predicts development of target organ damage (TOD) and cardiovascular disease. We hypothesized that blood pressure (BP)-related increased arterial stiffness is present in youth with elevated BP and is associated with TOD. METHODS: Participants were stratified by systolic BP into low- (systolic BP <75th percentile, n=155), mid- (systolic BP ≥80th and <90th percentile, n=88), and high-risk BP categories (≥90th percentile, n=139), based on age-, sex- and height-specific pediatric BP cut points. Clinic BP, 24-hour ambulatory BP monitoring, anthropometrics, and laboratory data were obtained. Arterial stiffness measures included carotid-femoral pulse wave velocity and aortic stiffness. Left ventricular mass index, left ventricular systolic and diastolic function, and urine albumin/creatinine were collected. ANOVA with Bonferroni correction was used to evaluate differences in cardiovascular risk factors, pulse wave velocity, and cardiac function across groups. General linear models were used to examine factors associated with arterial stiffness and to determine whether arterial stiffness is associated with TOD after accounting for BP. RESULTS: Pulse wave velocity increased across groups. Aortic distensibility, distensibility coefficient, and compliance were greater in low than in the mid or high group. Significant determinants of arterial stiffness were sex, age, adiposity, BP, and LDL (low-density lipoprotein) cholesterol. Pulse wave velocity and aortic compliance were significantly associated with TOD (systolic and diastolic cardiac function and urine albumin/creatinine ratio) after controlling for BP. CONCLUSIONS: Higher arterial stiffness is associated with elevated BP and TOD in youth emphasizing the need for primary prevention of cardiovascular disease.

Increased Arterial Stiffness Is Associated With Reduced Diastolic Function in Youth With Obesity and Type 2 Diabetes.

Background: Increased arterial stiffness is associated with diastolic dysfunction in adults. Data in youth are lacking, so we examined the impact of arterial stiffness on diastolic function in youth. Methods: We obtained diastolic function and augmentation index, pulse wave velocity, brachial artery distensibility, and carotid stiffness on 612 youth [10-24 years, 65% female, 38% normal weight, 36% obese, and 26% with type 2 diabetes mellitus (T2DM)]. Participants were classified as compliant (C) vs. stiff (S) arteries based on seven arterial stiffness parameters [Global Stiffness Index (GSI), S = GSI > 4). Mean differences in covariates were evaluated by Student's t-tests. A stepwise regression analysis was performed to determine if GSI was an independent predictor of diastolic function. Results: Lower diastolic function and more adverse cardiovascular disease (CVD) risk factors were present in the S group (n = 67) than the C group (n = 545) (p < 0.001). Covariates that were associated with diastolic dysfunction were higher GSI, male sex, higher body mass index (BMI), and systolic blood pressure (SBP) z-score (R 2 = 0.18 to 0.25; p ≤ 0.05). Conclusion: Adverse diastolic function is seen in youth with increased arterial stiffness independent of CVD risk factors. Interventions to improve arterial stiffness prior to clinical onset of diastolic dysfunction are needed to prevent development of heart failure.

Reduction in myocardial strain is evident in adolescents and young adults with obesity and type 2 diabetes.

AIMS/HYPOTHESIS: Heart failure is a complication of type 2 diabetes (T2DM). Echocardiography can identify subclinical systolic dysfunction in adults with T2DM. We hypothesized that reduced systolic strain was present in youth with T2DM. METHODS: Global longitudinal strain (GLS) was measured in 151 subjects with T2DM matched to lean (L = 146), and obese (O = 162) subjects (23.0 ± 4.0 years, 35% male, 63% African American). Anthropometrics, BP, HR, labs, and echocardiograms were obtained. ANOVA was performed to compare differences among groups, and ANCOVA to determine if T2DM remained an independent predictor after corrections. RESULTS: BP, lipid levels, and metabolic control worsened and GLS was reduced from L to O to T2DM. BMI was lower in L than O or T2DM. Global longitudinal strain rate (GLSR) was lower and LVM/ht2.7 was higher in O and T2DM as compared to L (all P ≤ .05). Presence of T2DM was an independent determinant of GLS and GLSR adjusted for most CV risk factors, but lost significance when BMI was added to the model. GLS = -21.6-age*0.088 - male*1.8 + 0.12*BMI + 0.045*DBP + 0.058*HR - 0.023*HDL (R2 = 0.38, P ≤ .0001); GLSR = -1.20-male*0.093 + WHR*0.48 + DBP*0.0029 (R2 = 0.23, P ≤ .0001). CONCLUSION: Both adiposity and T2DM have a deleterious effect on systolic cardiac function. Treatment of obesity in youth is necessary for prevention of future heart failure.

Remote diagnosis of congenital heart disease in southern Arizona: comparison between tele-echocardiography and videotapes.

OBJECTIVE: We report our experience with tele-echocardiography and echocardiograms recorded digitally or on videotape (recorded-echos) at The University of Arizona from August 2006 to December 2010 and compare their quality and diagnostic accuracy. MATERIALS AND METHODS: Tele-echocardiograms (tele-echos) were transmitted from the Yuma Regional Medical Center to The University of Arizona via a T-1 and aT-3 line at a bandwidth of 768 kilobits per second. Recorded-echos were shipped for interpretation to The University of Arizona by overnight mail. Diagnostic accuracy was assessed by comparing tele- and recorded-echos with electrocardiograms performed by a pediatric cardiologist (PedsCard-echos). RESULTS: Three hundred forty-six tele-echos in 260 patients and 455 recorded-echos in 406 patients were performed (median age, 6 and 8 days, respectively). Indications included possible congenital heart disease (CHD), patent ductus arteriosus (PDA), and persistent pulmonary hypertension of the newborn. Diagnostic categories included complex CHD, non-critical disease, PDA, and other. PedsCard-echos were available for 27% of the tele-echo and 30% of the recorded-echo patients. Comparisons between tele- and PedsCard-echo yielded no discrepancies in 12 (23%), expected resolution of condition in 26 (49%), and minor in 14 (26%). One (2%) major discrepancy was detected. Comparisons between recorded- and PedsCard-echo showed no discrepancies in 28 (40%), expected resolution of condition in 14 (20%), and minor discrepancies in 28 (40%) patients. No significant difference with respect to discrepancies was detected between tele- and recorded-echos. There was significant (p<0.01) improvement in tele- and recorded-echo study quality by 2010. CONCLUSIONS: (1) Tele-echocardiography can be performed successfully with excellent accuracy. (2) The quality of tele- and recorded-echo studies improved toward the end of the analysis period. (3) Although initially tele-echo studies were more accurate than recorded-echo studies, there was no difference between these two types of studies by the fourth year of the study. (4) Both tele- and recorded-echos were indispensible in the remote diagnosis of CHD.

A reevaluation of the threshold exposure level of inhaled JP-8 in mice.

C57BL/6 mice were nose-only exposed to JP-8 jet fuel at average concentrations of 45, 267, and 406 mg JP-8/m(3) for 1 hr/d for 7 days to further test the hypothesis that exposure to JP-8 concentrations below the current permissible exposure level (PEL) of 350 mg/m(3) will induce lung injury, and to validate a new "in-line, real-time" total hydrocarbon analysis system capable of measuring both JP-8 vapor and aerosol concentrations. Pulmonary function and respiratory permeability tests were performed 24 to 30 hr after the final exposures. No significant effects were observed at 45 or 267 mg/m(3). The only significant effect observed at 406 mg/m(3) was a decrease in inspiratory dynamic lung compliance. Morphological examination and morphometric analysis of distal lung tissue demonstrated that alveolar type II epithelial cells showed limited cellular damage with the notable exception of a significant increase in the volume density of lamellar bodies (vacuoles), which is indicative of increased surfactant production, at 45 and 406 mg/m(3). The terminal bronchial epithelium showed initial signs of cellular damage, but the morphometric analysis did not quantify these changes as significant. The morphometric analysis techniques appear to provide an increased sensitivity for detecting the deleterious effects of JP-8 as compared to the physiological evidence offered by pulmonary function or respiratory permeability tests. These observations suggest that the current 350 mg/m(3) PEL for both JP-8 jet fuel and for other more volatile petroleum distillates should be reevaluated and a lower, more accurate PEL should be established with regard human occupational exposure limits.