Using compositional analysis to explore the relationship between physical activity and cardiovascular health in children and adolescents with and without type 1 diabetes.

OBJECTIVE: The aim of this study was to use a compositional analysis approach to account for the inherent co-dependencies between behaviors and to explore how daily movement behaviors influence cardiovascular health in children with and without T1D. RESEARCH DESIGN AND METHODS: Augmentation index, pulse wave velocity (PWV) and heart rate variability were measured in 20 children with (11.9 ± 1.6 years) and 17 children without T1D (11.6 ± 2.2 years). Subsequently, physical activity and sleep were assessed at 20 Hz for 28 consecutive days using a wrist-worn accelerometer. Compositional analyses were utilized to explore the relative effects of each movement behavior and the overall movement complex on cardiovascular parameters, with predictive modeling used to explore the effects of reallocating 20 min between behaviors. RESULTS: Arterial stiffness markers were most influenced by the total movement composition, whereas autonomic function was most influenced by sedentary time and sleep relative to all other behaviors. Reallocation of time from moderate-to-vigorous physical activity (MVPA) to any other behavior was predicted to negatively affect all cardiovascular measures, independent of disease status, whereas reallocating time to MVPA was consistently predicted to improve all outcome measures. Additionally, the same intensity of physical activity appeared to be more potent for cardiovascular health in T1D children compared to nondiabetic peers. CONCLUSIONS: Intensity, rather than volume, of physical activity may be key in reducing risk of premature adverse changes in cardiovascular health, whereas increasing time in MVPA could potentially the slow progression of cardiovascular aging in children with diabetes.

Pulse transit time estimation of aortic pulse wave velocity and blood pressure using machine learning and simulated training data.

Recent developments in cardiovascular modelling allow us to simulate blood flow in an entire human body. Such model can also be used to create databases of virtual subjects, with sizes limited only by computational resources. In this work, we study if it is possible to estimate cardiovascular health indices using machine learning approaches. In particular, we carry out theoretical assessment of estimating aortic pulse wave velocity, diastolic and systolic blood pressure and stroke volume using pulse transit/arrival timings derived from photopletyshmography signals. For predictions, we train Gaussian process regression using a database of virtual subjects generated with a cardiovascular simulator. Simulated results provides theoretical assessment of accuracy for predictions of the health indices. For instance, aortic pulse wave velocity can be estimated with a high accuracy (r > 0.9) when photopletyshmography is measured from left carotid artery using a combination of foot-to-foot pulse transmit time and peak location derived for the predictions. Similar accuracy can be reached for diastolic blood pressure, but predictions of systolic blood pressure are less accurate (r > 0.75) and the stroke volume predictions are mostly contributed by heart rate.

Subclinical atherosclerosis in systemic sclerosis and rheumatoid arthritis: a comparative matched-cohort study.

Systemic autoimmune inflammatory disorders confer a higher risk of cardiovascular (CV) disease leading to increased morbidity and mortality and reduced life expectancy compared to the general population. CV risk in systemic sclerosis (SSc) has not been studied extensively but surrogate markers of atherosclerosis namely carotid intima media thickness (cIMT) and pulse wave velocity (PWV) are impaired in some but not all studies in SSc patients. The aim of this study was to investigate the prevalence of subclinical atherosclerosis assessed by cIMT and PWV between two well-characterized SSc and Rheumatoid Arthritis (RA) cohorts. Consecutive SSc patients attending the Scleroderma Clinic were compared with RA patients recruited in the Dudley Rheumatoid Arthritis Co-morbidity Cohort (DRACCO), a prospective study examining CV burden in RA. Augmentation Index (Aix75) and cIMT were measured in all participants. Propensity score matching was utilised to select patients from the two cohorts with similar demographic characteristics, CV risk factors and inflammatory load. Unpaired analysis was performed using unpaired t test for continuous variables and χ2 test for dichotomous variables. Statistical analysis was repeated using paired t test for continuous normal variables and McNemar's test for dichotomous variables. Fifty five age- and sex-matched SSc and RA patients were included in the analysis. No difference was demonstrated between SSc and RA subjects regarding cIMT (0.66 mm vs 0.63 mm, respectively) and Aix75% measurements (33.4 vs 31.7, respectively) neither in paired (p = 0.623 for cIMT and p = 0.204 for Aix%) nor in unpaired t test analysis (p = 0.137 for cIMT and p = 0.397 for AIx%). The results of this comparative study show that subclinical atherosclerosis is comparable between SSc and RA, a systemic disease with well-defined high atherosclerotic burden. Such findings underscore the importance of CV risk management in SSc in parallel with other disease-related manifestations.

Validity and reliability of lower-limb pulse-wave velocity assessments using an oscillometric technique.

NEW FINDINGS: What is the central question of this study? There is growing interest in the effects of sedentarism on central and peripheral cardiovascular health. To permit further investigation, including larger epidemiological studies, there is a need to identify arterial health assessment tools that are valid (accurate) and reliable (precise), yet practical. What is the main finding and its importance? Lower-limb vascular health (femoral-ankle pulse-wave velocity) can be determined in a supine position with accuracy and precision using an oscillometrically based device. This technology might help to improve our understanding of the pathological mechanisms linking cardiovascular disease to sedentarism, including the interaction between peripheral and central vasculature. ABSTRACT: There is a growing interest in the deleterious effects of sedentary behaviour on lower-limb arterial health. To permit further investigation, including larger epidemiological studies, there is a need to identify lower-limb arterial health assessment tools that are valid and reliable, yet simple to administer. In this study, we sought to determine the validity and between-day reliability of femoral-ankle pulse-wave velocity (faPWV) measures obtained using an oscillometrically based device (SphygmocCor XCEL) in supine and seated positions. Doppler ultrasound was used as the criterion. A total of 47 healthy adults were recruited for validity (n = 32) and reliability (n = 15) analyses. Validity was determined by measuring faPWV in seated and supine positions using the XCEL and Doppler ultrasound devices, in a randomized order. Between-day reliability was determined by measuring seated and supine faPWV using the XCEL on three different mornings, separated by a maximum of 7 days. The validity criterion [absolute standard error of estimate (aSEE) < 1.0 m s-1 ] was met in the supine [aSEE = 0.8 m s-1 , 95% confidence interval (CI) 0.4-1.0], but not in the seated (aSEE = 1.2 m s-1 , 95% CI 1.1-1.2) position. Intraclass correlation coefficient (ICC) estimates revealed that the XCEL demonstrated good reliability in the supine position (ICC = 0.83, 95% CI 0.65-0.93), but poor reliability in the seated position (ICC = 0.29, 95% CI 0.23-0.63). The oscillometric XCEL device can be used to determine lower-limb pulse-wave velocity with acceptable validity and reliability in the conventionally recommended supine position, but not in the seated position.

First-trimester ductus venosus velocity ratio as a marker of major cardiac defects.

OBJECTIVES: To examine ductus venosus (DV) flow in fetuses with and those without a cardiac defect and to evaluate different phases of DV flow in addition to the standard assessment of DV pulsatility index for veins (PIV) and the a-wave. METHODS: This was a retrospective study of singleton pregnancies that underwent first-trimester ultrasound screening, which included DV flow assessment, at the University of Tübingen (between 2010 and 2017) or the University of Cologne (between 2013 and 2016). The study population comprised normal fetuses and fetuses with major cardiac defects at a ratio of 10:1. For each fetus, the following parameters of the DV waveform were evaluated: qualitative assessment of the a-wave, PIV measurement and ratios of flow velocities during the S-wave (S) or D-wave (D) and the a-wave (a) or v-wave (v). Reproducibility of DV-PIV and DV flow ratios was evaluated in 30 fetuses in which the DV flow was assessed twice. RESULTS: Our study population included 480 anatomically normal fetuses and 48 with a cardiac defect. Median fetal nuchal translucency (NT) in the normal and in the affected group was 1.9 mm and 2.6 mm, respectively. In five (1.0%) of the normal and 18 (37.5%) of the affected cases, fetal NT thickness was above the 99th centile. In the normal group, the DV a-wave was reversed in 15 (3.1%) cases and the DV-PIV was above the 95th centile in 25 (5.2%). In the cases with cardiac defects, the a-wave was reversed and the DV-PIV measurement was above the 95th centile in 26 (54.2%). The reproducibility of measurement of the ratios of DV flow velocities was similar to that of the DV-PIV. Most cardiac defects were associated with an abnormal a/S or a/D ratio. If the cut-off for these two ratios was set at the 5th centile of the normal distribution, the detection rate of fetal cardiac anomalies would be 62.5%. This compares favorably with the DV-PIV, which detects 26 (54.2%) of the affected fetuses for the same threshold. CONCLUSION: In the first trimester, the a/S ratio has the potential to detect approximately 60% of congenital cardiac defects for a false-positive rate of 5%. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Longitudinal changes in vascular function parameters in pregnant women with chronic hypertension and association with adverse outcome: a cohort study.

OBJECTIVES: Raised vascular function measures are associated with adverse maternal and perinatal outcomes in low-risk pregnancy. This study aimed to evaluate the association between longitudinal vascular function parameters and adverse outcome in pregnant women with chronic hypertension, and to assess whether these measures vary according to baseline parameters such as black ethnicity. METHODS: This was a nested cohort study of women with chronic hypertension and a singleton pregnancy recruited to the PANDA (Pregnancy And chronic hypertension: NifeDipine vs lAbetalol as antihypertensive treatment) study at one of three UK maternity units. Women had serial pulse-wave analyses performed using the Arteriograph®, while in a sitting position, from 12 weeks' gestation onwards. Statistical analysis was performed using random-effects logistic regression models. Longitudinal vascular parameters were compared between women who developed superimposed pre-eclampsia (SPE) and those who did not, between women who delivered a small-for-gestational-age (SGA) infant (birth weight < 10th centile) and those who delivered an infant with birth weight ≥ 10th centile and between women of black ethnicity and those of non-black ethnicity. RESULTS: The cohort included 97 women with chronic hypertension and a singleton pregnancy, of whom 90% (n = 87) were randomized to antihypertensive treatment and 57% (n = 55) were of black ethnicity, with up to six (mean, three) longitudinal vascular function assessments. SPE was diagnosed in 18% (n = 17) of women and 30% (n = 29) of infants were SGA. In women who developed subsequent SPE, compared with those who did not, mean brachial systolic blood pressure (SBP) (148 mmHg vs 139 mmHg; P = 0.002), mean diastolic blood pressure (DBP) (87 mmHg vs 82 mmHg; P = 0.01), mean central aortic pressure (139 mmHg vs 128 mmHg; P = 0.001) and mean augmentation index (AIx-75) (29% vs 22%; P = 0.01) were significantly higher across gestation. In women who delivered a SGA infant compared to those who delivered an infant with birth weight ≥ 10th centile, mean brachial SBP (146 mmHg vs 138 mmHg; P = 0.001), mean DBP (86 mmHg vs 82 mmHg; P = 0.01), mean central aortic pressure (137 mmHg vs 127 mmHg; P < 0.0001) and mean pulse-wave velocity (9.1 m/s vs 8.5 m/s; P = 0.02) were higher across gestation. No longitudinal differences were found in vascular function parameters in women of black ethnicity compared with those of non-black ethnicity. CONCLUSION: There were persistent differences in vascular function parameters and brachial blood pressure throughout pregnancy in women with chronic hypertension who later developed adverse maternal or perinatal outcome. Further investigation into the possible clinical use of these findings is warranted. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

High sodium intake and sodium to potassium ratio may be linked to subsequent increase in vascular damage in adults aged 40 years and older: the Korean multi-rural communities cohort (MRCohort).

PURPOSE: Subclinical vascular damage is a chronic intermediate process in cardiovascular disease (CVD) and high sodium (Na) has been regarded as an adverse factor in subclinical vascular health; however, the longitudinal relationship between Na intake and subclinical vascular damage has not been studied. We aimed to evaluate the longitudinal relationship of dietary Na intake and sodium to potassium ratio (Na:K) with brachial-ankle pulse wave velocity (baPWV) and carotid intima media thickness (cIMT) in healthy adults aged 40 years and older in Korea. METHODS: The present study was based on participants (n = 2145 for baPWV analysis and n = 2494 for cIMT analysis) who visited three times during 2005-2013 (median 5.3 years of follow-up). We used both dietary Na intake and Na:K at baseline and its average (baseline, 2nd, 3rd), which was obtained from food frequency questionnaire (FFQ) as exposure at every visit. baPWV and cIMT levels at the third visit and change from baseline to the third visit were used to represent the level of subclinical vascular damage. RESULTS: After adjustment for potential confounders, significant positive relationships between dietary Na intake and both baPWV3rd and cIMT3rd were observed (baPWV: p for trend ≤ 0.0001 for Naaverage; cIMT: p for trend = 0.013 for Naaverage). Compared with Na:Ks less than 1.0, the levels of both baPWV and cIMT were higher for participants with Na:Ks over 1.0 (baPWV: p for trend = 0.0002 for Na:Kaverage; cIMT: p for trend = 0.005 for Na:Kaverage). Similar significant trends were shown in relationships between dietary Na intake and Na:K and changes in baPWV and cIMT levels. CONCLUSIONS: In conclusion, dietary Na intake and Na:K may be positively linked to subsequent baPWV and cIMT levels in adults aged 40 years and older in Korea. Our findings may provide informative evidence on subclinical vascular damage, particularly for populations with relatively high dietary Na intake and low dietary K intake.

Comparison of vascular-related diseases in their associations with carotid femoral pulse wave velocity: From the Beijing Vascular Disease Patients Evaluation Study (BEST Study).

AIMS: Carotid femoral pulse wave velocity (CF-PWV) is associated with vascular-related diseases. However, this association has rarely been compared in the same study population, which would improve our understanding of the role of these diseases in developing arteriosclerosis. This study was designed to assess arterial function in different vascular-related diseases and the potential interrelationships between these diseases and arteriosclerosis. METHODS: There were 13 798 participants with or without established vascular-related diseases, including hypertension, diabetes, coronary artery disease (CAD), stroke and peripheral artery disease (PAD), enrolled into the study from 2010 to 2016, comprising 6648 males and 7150 females. The odds ratio (OR) of arteriosclerosis (defined as CF-PWV >12 m/s) in associations with the vascular-related diseases was modelled using multivariable logistic regression analyses to adjust for possible confounders. RESULTS: Compared with participants without vascular-related diseases, those presenting the diseases showed a significantly higher prevalence and age- and sex-adjusted OR of arteriosclerosis (all P < .001). After further adjustment for hypertension, the ORs became much smaller and not significant for CAD or stroke. Compared with apparently healthy participants, participants with each of the diseases showed a significantly higher adjusted OR (range: 2.46-3.30, all P < .001); participants with each vascular-related disease only showed much smaller and non-significant ORs, except for hypertension (OR = 2.73, 95% CI: 2.46, 3.04). After further adjustment for hypertension, these ORs became non-significant (range: 0.81-1.36, all P > .05). CONCLUSIONS AND CLINICAL IMPLICATIONS: The associations between arteriosclerosis and diseases other than hypertension were largely explained by the association with hypertension, indicating that hypertension could be the single most important factor that leads to arteriosclerosis. TRIAL REGISTRATION: ClinicalTrials.gov NCT02569268.

Blood Pressure and Arterial Stiffness in Kenyan Adolescents With the Sickle Cell Trait.

The potential association between sickle cell trait (SCT) and increased arterial stiffness/blood pressure (BP) has not been evaluated in detail despite its association with stroke, sudden death, and renal disease. We performed 24-hour ambulatory BP monitoring and arterial stiffness measurements in adolescents raised in a malaria-free environment in Kenya. Between December 2015 and June 2016, 938 randomly selected adolescents (ages 11-17 years) who had been continuous residents of Nairobi from birth were invited to participate in the study. Standard clinic BP measurement was performed, followed by 24-hour ambulatory BP monitoring and arterial stiffness measurement using an Arteriograph24 (TensioMed Ltd., Budapest, Hungary) device. SCT status was determined using DNA genotyping in contemporaneously collected blood samples. Of the 938 adolescents invited to participate, 609 (65%) provided complete data for analysis. SCT was present in 103 (15%). Mean 24-hour systolic and diastolic BPs were 116 (standard deviation (SD), 11.5) mm Hg and 64 (SD, 7) mm Hg, respectively, in children with SCT and 117 (SD, 11.4) mm Hg and 64 (SD, 6.8) mm Hg, respectively, in non-SCT children. Mean pulse wave velocity (PWV) was 7.1 (SD, 0.8) m/second and 7.0 (SD, 0.8) m/second in SCT and non-SCT children, respectively. We observed no differences in PWV or in any clinic or ambulatory BP-derived measures between adolescents with and without SCT. These data suggest that SCT does not independently influence BP or PWV.

Probability of At Least One High Arterial Blood Pressure Measurement in Elderly Patients with Healthy Vascular Aging in Two Years of Follow-Up.

BACKGROUND/AIMS: Elderly patients with normal systemic arterial blood pressure associated with femoral carotid pulse velocity (cf-PWV) less than 7.6 m/s and without associated comorbidities are considered to have good vascular health. The aim of the current study was to verify the probability that elderly patients with good vascular health have at least one blood pressure measurement above the different thresholds for systolic blood pressure (120, 130 and 140 mmHg) during two years of follow-up. METHODS: We selected 72 normotensive patients (< 140/90 mmHg) without comorbidities and divided them into group A, with cf-PWV < 7.6 m/s (n = 27; 65 ± 4 years), and group B, with cf-PWV ≥ 7.6 m/s (n = 45; 66± 8 years). These patients were followed for two years and were observed in 3 outpatient visits (0, 12 and 24 months). At each visit, the brachial pressures were indirectly measured in triplicate, and applanation tonometry was performed. RESULTS: When group A and group B were compared, the odds ratio (OR) of having a systolic pressure measurement ≥ 140 mmHg in two years of follow-up was 0.22 (P < 0.0001); ≥ 130 mmHg, the OR was 0.49 (P < 0.0007), and ≥ 120 mmHg, the OR was 0.54 (P < 0.001). Group A and group B showed increased values of cf-PWV during the two years of follow-up (P < 0.05). Changes in the average systolic brachial pressure were not significant during the two years in groups A or B. CONCLUSION: Vascular health in elderly individuals seems to protect against occasional elevations in systemic arterial pressure.

Pulse contour analysis of arterial waveform in a high fidelity human patient simulator.

The measurement of cardiac output (CO) may be useful to improve the assessment of hemodynamics during simulated scenarios. The purpose of this study was to evaluate the feasibility of introducing an uncalibrated pulse contour device (MostCare, Vytech, Vygon, Padova, Italy) into the simulation environment. MostCare device was plugged to a clinical monitor and connected to the METI human patient simulator (HPS) to obtain a continuous arterial waveform analysis and CO calculation. In six different simulated clinical scenarios (baseline, ventricular failure, vasoplegic shock, hypertensive crisis, hypovolemic shock and aortic stenosis), the HPS-CO and the MostCare-CO were simultaneously recorded. The level of concordance between the two methods was assessed by the Bland and Altman analysis. 150-paired CO values were obtained. The HPS-CO values ranged from 2.3 to 6.6 L min-1 and the MostCare-CO values from 2.8 to 6.4 L min-1. The mean difference between HPS-CO and MostCare-CO was - 0.3 L min-1 and the limits of agreement were - 1.5 and 0.9 L min-1. The percentage of error was 23%. A good correlation between HPS-CO and MostCare-CO was observed in each scenario of the study (r = 0.88). Although MostCare-CO tended to underestimate the CO over the study period, good agreements were found between the two methods. Therefore, a pulse contour device can be integrated into the simulation environment, offering the opportunity to create new simulated clinical settings.

Is Hepatic Triglyceride Content Associated with Aortic Pulse Wave Velocity and Carotid Intima-Media Thickness? The Netherlands Epidemiology of Obesity Study.

Purpose To test the hypothesis that hepatic triglyceride content is associated with subclinical vascular impairment and is not confounded by various cardiometabolic risk factors. Materials and Methods This study was approved by the institutional review board, and all participants gave written informed consent. In this cross-sectional analysis of baseline measurements of the Netherlands Epidemiology of Obesity study, a population-based cohort study, 1899 participants (52% men; mean age, 55 years ± 6 [standard deviation]) underwent magnetic resonance (MR) spectroscopy and MR imaging to assess hepatic triglyceride content, aortic pulse wave velocity (PWV), and visceral fat. Carotid intima-media thickness (IMT) was acquired and measured by trained research nurses according to standard procedures. Multivariate regression analyses were used to study associations of hepatic triglyceride content with total and regional aortic PWV and carotid IMT while adjusting for several possible confounding factors, including the metabolic syndrome. Results Total aortic PWV (mean difference, 0.5 m/sec; 95% confidence interval [CI]: 0.3, 0.7) and carotid IMT (mean difference, 37 µm; 95% CI: 25, 49) were higher in participants with hepatic steatosis. After adjusting for various covariates, a 10-fold increase in hepatic triglyceride content was associated with an increased mean aortic PWV of 0.19 m/sec (95% CI: 0.03, 0.36) in total and an increased mean aortic PWV of 0.42 m/sec (95% CI: 0.03, 0.81) in the abdominal segment. A 10-fold increase in hepatic triglyceride content was also associated with an increased mean carotid IMT of 15 µm (95% CI: 0, 29) but not after additional adjustments for visceral and total body fat. Conclusion In this relatively large population-based cohort study, hepatic triglyceride content was associated with aortic pulse wave velocity and carotid IMT. These associations were only partly explained by the metabolic syndrome and visceral adiposity, suggesting a possible specific contribution of hepatic steatosis to subclinical vascular impairment. © RSNA, 2017 Online supplemental material is available for this article.

Pulse Waveform Analysis: Is It Ready for Prime Time?

PURPOSE OF REVIEW: Arterial pulse waveform analysis has a long tradition but has not pervaded medical routine yet. This review aims to answer the question whether the methodology is ready for prime time use. The current methodological consensus is assessed, existing technologies for waveform measurement and pulse wave analysis are discussed, and further needs for a widespread use are proposed. RECENT FINDINGS: A consensus document on the understanding and analysis of the pulse waveform was published recently. Although still some discrepancies remain, the analysis using both pressure and flow waves is favoured. However, devices which enable pulse wave measurement are limited, and the comparability between devices is not sufficiently given. Pulse waveform analysis has the potential for prime time. It is currently on a way towards broader use, but still needs to overcome challenges before settling its role in medical routine.

Cross-section analysis of coal workers' pneumoconiosis and higher brachial-ankle pulse wave velocity within Kailuan study.

BACKGROUND: Brachial-ankle pulse wave velocity (baPWV) is an independent predictor of cardiovascular events and mortality. However, there is no related data on the association of baPWVwith coal workers' pneumoconiosis (CWP). We explored the baPWV in subjects withCWP and the associated risk factors. METHODS: Thiscase-control study included 1,007 male CWP cases without a history of stroke and coronary heart disease and 1,007 matched controls from the Kailuan cohort study. All of the participants underwent assessment for baPWV and traditional cardiovascular risk factors. The cumulative silica dust exposure (work history linked to a job-exposure matrix) was estimated for the CWP cases. RESULTS: Compared with the controls, the CWP cases had higher baPWV (1762.0 ± 355 cm/s vs. 1718.6 ± 354 cm/s, P = 0.006) and a higher risk of increased baPWV (defined as more than the median baPWV of the population distribution; odds ratio 1.43, 95% confidence interval 1.11-1.83) after adjusting for traditional cardiovascular risk factors. Age ≥60 years, body mass index, heart rate, and hypertension were all significantly associated with increased baPWV in the CWP cases. Compared to non-CWP subjects without hypertension, the odds ratios for increased baPWV gradually increased (P for trend, 0.001) across the CWP subjects without hypertension (odds ratio 1.20, 95%confidence interval 0.90-1.61), subjects with hypertension alone (odds ratio 2.54, 95% confidence interval 1.95-3.30), and CWP subjects with hypertension (odds ratio 3.34, 95% confidence interval 2.56-4.37). We detected a significant positive exposure-response relationship between silica dust-exposure quartiles and increased baPWV in CWP cases (P for trend < 0.001). CONCLUSIONS: For patients with CWP, increased baPWV was associated with traditional cardiovascular risk factors and long-term silica dust exposure.

Echocardiographically Derived Pulse Wave Velocity and Diastolic Dysfunction Are Associated with an Increased Incidence of Atrial Fibrillation in Patients with Systolic Heart Failure.

BACKGROUND: Chronic heart failure (CHF) is an established risk factor of atrial fibrillation (AF), but the prognostic value of cardiac and hemodynamic parameters in assessing the risk of developing AF among patients with CHF is less defined. METHODS AND RESULTS: We followed an outpatients cohort of CHF patients secondary to left ventricular (LV) systolic dysfunction, who were free of AF at baseline. All patients underwent clinical evaluation, comprehensive echocardiography, and blood drawing in the same morning. Aortic pulse wave velocity (aPWV), a measure of aortic stiffness, was determined by Doppler echocardiography. A total of 77 patients (age 63 ± 9 years; 79% male) with mean LVEF (34 ± 8%) formed the study population. Fifteen patients developed incidental AF. At baseline, CHF patients who developed AF during follow-up had higher E-wave velocity (75 ± 2 cm/sec vs. 60 ± 2 cm/sec; P = 0.02), higher difference duration between mitral and pulmonary vein A velocity (A'-A), (10 ± 35 msec vs. 43 ± 44 msec P = 0.02), aPWV (7.1 ± 2.6 vs. 5.3 ± 1.9 m/sec P = 0.004), and furosemide dosage (110 ± 145 mg vs. 49 ± 48 mg P = 0.01) than those remaining free from AF. The two groups of patients did not significantly differ in terms of NYHA, LV volumes, ejection fraction, left atrial volume, creatinine, hemoglobin, renin, epinephrine, amino-terminal propeptide of type III and I procollagens, ACE inhibitor, and ß-blocker dose (P > 0.1 for all). Notably, higher aPWV (P = 0.01) and longer A-A' duration (P = 0.04) were associated with an increased incidence of AF, independently of potential confounders. CONCLUSIONS: Increased aortic stiffness and LV diastolic dysfunction are strong predictors of new onset of AF among patients with systolic CHF.

Continuous noninvasive cardiac output determination using the CNAP system: evaluation of a cardiac output algorithm for the analysis of volume clamp method-derived pulse contour.

The CNAP system (CNSystems Medizintechnik AG, Graz, Austria) provides noninvasive continuous arterial pressure measurements by using the volume clamp method. Recently, an algorithm for the determination of cardiac output by pulse contour analysis of the arterial waveform recorded with the CNAP system became available. We evaluated the agreement of the continuous noninvasive cardiac output (CNCO) measurements by CNAP in comparison with cardiac output measurements invasively obtained using transpulmonary thermodilution (TDCO). In this proof-of-concept analysis we studied 38 intensive care unit patients from a previously set up database containing CNAP-derived arterial pressure data and TDCO values obtained with the PiCCO system (Pulsion Medical Systems SE, Feldkirchen, Germany). We applied the new CNCO algorithm retrospectively to the arterial pressure waveforms recorded with CNAP and compared CNCO with the corresponding TDCO values (criterion standard). Analyses were performed separately for (1) CNCO calibrated to the first TDCO (CNCO-cal) and (2) CNCO autocalibrated to biometric patient data (CNCO-auto). We did not perform an analysis of trending capabilities because the patients were hemodynamically stable. The median age and APACHE II score of the 22 male and 16 female patients was 63 years and 18 points, respectively. 18 % were mechanically ventilated and in 29 % vasopressors were administered. Mean ± standard deviation for CNCO-cal, CNCO-auto, and TDCO was 8.1 ± 2.7, 6.4 ± 1.9, and 7.8 ± 2.4 L/min, respectively. For CNCO-cal versus TDCO, Bland-Altman analysis demonstrated a mean difference of +0.2 L/min (standard deviation 1.0 L/min; 95 % limits of agreement -1.7 to +2.2 L/min, percentage error 25 %). For CNCO-auto versus TDCO, the mean difference was -1.4 L/min (standard deviation 1.8 L/min; 95 % limits of agreement -4.9 to +2.1 L/min, percentage error 45 %). This pilot analysis shows that CNCO determination is feasible in critically ill patients. A percentage error of 25 % indicates acceptable agreement between CNCO-cal and TDCO. The mean difference, the standard deviation, and the percentage error between CNCO-auto and TDCO were higher than between CNCO-cal and TDCO. A hyperdynamic cardiocirculatory state in a substantial number of patients and the hemodynamic stability making trending analysis impossible are main limitations of our study.

Diagnostic accuracy of stroke volume variation measured with uncalibrated arterial waveform analysis for the prediction of fluid responsiveness in patients with impaired left ventricular function: a prospective, observational study.

Uncalibrated arterial waveform analysis enables dynamic preload assessment in a minimally invasive fashion. Evidence about the validity of the technique in patients with impaired left ventricular function is scarce, while adequate cardiac preload assessment would be of great value in these patients. The aim of this study was to investigate the diagnostic accuracy of stroke volume variation (SVV) measured with the FloTrac/Vigileo™ system in patients with impaired left ventricular function. In this prospective, observational study, 22 patients with a left ventricular ejection fraction of 40 % or less undergoing elective coronary artery bypass grafting were included. Patients were considered fluid responsive if cardiac output increased with 15 % or more after volume loading (7 ml kg(-1) ideal body weight). The following variables were calculated: area under the receiver operating characteristics (ROC) curve, ideal cut-off value for SVV, sensitivity, specificity, positive and negative predictive values, and overall accuracy. In addition, SVV cut-off points to obtain 90 % true positive and 90 % true negative predictions were determined. ROC analysis revealed an area under the curve of 0.70 [0.47; 0.92]. The ideal SVV cut-off value was 10 %, with a corresponding sensitivity and specificity of 56 and 69 % respectively. Overall accuracy was 64 %, positive and negative predictive values were 69 and 56 % respectively. SVV values to obtain more than 90 % true positive and negative predictions were 16 and 6 % respectively. The ability of uncalibrated arterial waveform analysis SVV to predict fluid responsiveness in patients with impaired LVF was low.

Comparison of an advanced minimally invasive cardiac output monitoring with a continuous invasive cardiac output monitoring during lung transplantation.

The aim of this study was to compare a continuous non-calibrated left heart cardiac index (CI) measurement by arterial waveform analysis (FloTrac(®)/Vigileo(®)) with a continuous calibrated right heart CI measurement by pulmonary artery thermodilution (CCOmbo-PAC(®)/Vigilance II(®)) for hemodynamic monitoring during lung transplantation. CI was measured simultaneously by both techniques in 13 consecutive lung transplants (n = 4 single-lung transplants, n = 9 sequential double-lung transplants) at distinct time points perioperatively. Linear regression analysis and Bland-Altman analysis with percentage error calculation were used for statistical comparison of CI measurements by both techniques. In this study the FloTrac(®) system underestimated the CI in comparison with the continuous pulmonary arterial thermodilution (p < 0.000). For all measurement pairs we calculated a bias of -0.55 l/min/m(2) with limits of agreement between -2.31 and 1.21 l/min/m(2) and a percentage error of 55 %. The overall correlations before clamping a branch oft the pulmonary artery (percentage error 41 %) and during the clamping periods of a branch oft the pulmonary artery (percentage error 66 %) failed to reached the required percentage error of less than 30 %. We found good agreement of both CI measurements techniques only during the measurement point "15 min after starting the second one-lung ventilation period" (percentage error 30 %). No agreement was found during all other measurement points. This pilot study shows for the first time that the CI of the FloTrac(®) system is not comparable with the continuous pulmonary-artery thermodilution during lung transplantation including the time periods without clamping a branch of the pulmonary artery. Arterial waveform and continuous pulmonary artery thermodilution are, therefore, not interchangeable during these complex operations.

Respiratory variations in the photoplethysmographic waveform amplitude depend on type of pulse oximetry device.

Respiratory variations in the photoplethysmographic waveform amplitude predict fluid responsiveness under certain conditions. Processing of the photoplethysmographic signal may vary between different devices, and may affect respiratory amplitude variations calculated by the standard formula. The aim of the present analysis was to explore agreement between respiratory amplitude variations calculated using photoplethysmographic waveforms available from two different pulse oximeters. Analysis of registrations before and after fluid loads performed before and after open-heart surgery (aortic valve replacement and/or coronary artery bypass grafting) with patients on controlled mechanical ventilation. Photoplethysmographic (Nellcor and Masimo pulse oximeters) and arterial pressure waveforms were recorded. Amplitude variations induced by ventilation were calculated and averaged over ten respiratory cycles. Agreements for absolute values are presented in scatterplots (with least median square regression through the origin, LMSO) and Bland-Altman plots. Agreement for trending presented in a four-quadrant plot. Agreement between respiratory photoplethysmographic amplitude variations from the two pulse oximeters was poor with LMSO ΔPOPNellc = 1.5 × ΔPOPMas and bias ± limits of agreement 7.4 ± 23 %. Concordance rate with a fluid load was 91 %. Agreement between respiratory variations in the photoplethysmographic waveform amplitude calculated from the available signals output by two different pulse oximeters was poor, both evaluated by LMSO and Bland-Altman plot. Respiratory amplitude variations from the available signals output by these two pulse oximeters are not interchangeable.