Measurements In Supine Position Research Articles

DIFFERENCES IN THE PROGNOSTIC VALUE OF TOTAL CHOLESTEROL ACCORDING TO GRADES OF HYPERTENSION IN THE OLD-HTA LYONʼS COHORT

Objective: Patients with grade 3 hypertension are categorized at high risk patients and a LDL target below 1.0 g/L has been recommended by the European Guidelines. However, the level of evidence for this subgroup is scarce and their risk is not assessed by SCORE. The aim of the present study was to test the prognostic value of total cholesterol in our historic cohort of hypertensive patients including an important part of patients with grade 3 hypertension. Design and method: A total of 1909 individuals from the OLD-HTA Lyon's cohort of hypertensives were categorized in grade 1–2 hypertension (47.3%) and in grade 3 hypertension (52.7%) according to recent European guidelines. Systolic (SBP) and diastolic blood pressure (DBP) were recorded as the average of six measurements in supine position. An overnight fasting blood sample was drawn for total cholesterol. Patients were classified according to tertiles of baseline cholesterol (<2.0 g/L, 2.0–2.4 g/L and >2.4 g/L) Results: Baseline characteristics of the cohort were as follow: 45.1+/−13.4 years, 60.8% of men, 48.1% of smokers, 13.2% of diabetics, 22.7% of secondary prevention, SBP/DBP 180+/−32 mmHg/104+/−20 mmHg. During a 30 years follow-up, we observed 1127 death and 598 from cardiovascular causes. Kaplan-Meier curves demonstrated a gradual increased risk of all-cause and cardiovascular death according to tertiles of cholesterol (Figure, p < 0.001). Then, we performed a multivariate Cox regression analysis adjusted for all confounders. In grade 1 or 2 hypertension, we observed an independent increased risk of cardiovascular (tertile 2 vs. 1 HR 1.31 [0.86–2.01], tertile 3 vs. 1 HR 1.66 [1.05–2.62]) and all-cause death (tertile 2 vs. 1 HR 1.26 [0.94–1.69], tertile 3 vs. 1 HR 1.49 [1.09–2.04]) for total cholesterol. In grade 3 hypertension, total cholesterol was not independently associated with cardiovascular (tertile 2 vs. 1 HR 1.11 [0.83–1.50], tertile 3 vs. 1 HR 1.08 [0.79–1.48]) and all-cause death (tertile 2 vs. 1 HR 1.09 [0.88–1.35], tertile 3 vs. 1 HR 0.99 [0.79–1.25]).Conclusions: Our results confirmed the prognostic value of total cholesterol on long-term mortality in hypertensive patients. However, its independent impact on severe forms of hypertension needs to be clarified.

THE ORTHOSTATIC HYPOTENSION AS A PREDICTOR OF CLINIC COMPLICATIONS IN HYPERTENSIVE PATIENTS WHO UNDERWENT NON-CARDIAC SURGERIES

Objective: Evaluate preoperative orthostatic hypotension as a predictor of clinical complications after non-cardiac surgery in hypertensive patients. Design and method: This was a prospective observational study. We included adult hypertensive patients scheduled for elective noncardiac surgery in an university hospital. Patients with heart failure or end-stage renal disease were excluded, as well as those that were not able to stand up. Each patient had their blood pressure measured in the ward before surgery. Blood presure was measured 3 times with a one-minute interval between measurements in supine position and was repeated after three minutes in orthostatic position. We defined orthostatic hypotension as a reduction in systolic blood pressure >20 mmHg. All patients in the study were followed up until discharge from hospital. We used student t test, chi-square and Pearson correlation coefficient as appropriate for statistical analysis. Possible confounding factors were controlled by logistic regression analysis. Results: We included 146 patients. Mean age was 63 years and 48% (70) were female. Most common surgeries were gastrointestinal and urologic. Orthostatic hypotension occurred in 5.2% (7) of patients and mean blood pressure drop was 28 mmHg. No patients died but clinical complications occurred in 46% (67); the most common were infections and acute renal failure. After logistic regression, age, race and orthostatic hypotension remained significant predictors of clinical complications. Conclusions: Orthostatic hypotension is a predictor of clinical complications after elective noncardiac surgeries in hypertensive patients.

Accuracy and reliability of noninvasive stroke volume monitoring via ECG-gated 3D electrical impedance tomography in healthy volunteers.

Cardiac output (CO) and stroke volume (SV) are parameters of key clinical interest. Many techniques exist to measure CO and SV, but are either invasive or insufficiently accurate in clinical settings. Electrical impedance tomography (EIT) has been suggested as a noninvasive measure of SV, but inconsistent results have been reported. Our goal is to determine the accuracy and reliability of EIT-based SV measurements, and whether advanced image reconstruction approaches can help to improve the estimates. Data were collected on ten healthy volunteers undergoing postural changes and exercise. To overcome the sensitivity to heart displacement and thorax morphology reported in previous work, we used a 3D EIT configuration with 2 planes of 16 electrodes and subject-specific reconstruction models. Various EIT-derived SV estimates were compared to reference measurements derived from the oxygen uptake. Results revealed a dramatic impact of posture on the EIT images. Therefore, the analysis was restricted to measurements in supine position under controlled conditions (low noise and stable heart and lung regions). In these measurements, amplitudes of impedance changes in the heart and lung regions could successfully be derived from EIT using ECG gating. However, despite a subject-specific calibration the heart-related estimates showed an error of 0.0 ± 15.2 mL for absolute SV estimation. For trending of relative SV changes, a concordance rate of 80.9% and an angular error of −1.0 ± 23.0° were obtained. These performances are insufficient for most clinical uses. Similar conclusions were derived from lung-related estimates. Our findings indicate that the key difficulty in EIT-based SV monitoring is that purely amplitude-based features are strongly influenced by other factors (such as posture, electrode contact impedance and lung or heart conductivity). All the data of the present study are made publicly available for further investigations.

OP.1A.09] ORTHOSTATIC HYPERTENSION PREDICTS MASKED HYPERTENSION IN THE VERY ELDERLY TREATED HYPERTENSIVES

Objective: Masked hypertension (MHT) and isolated nocturnal hypertension are associated with increased risk of target organ damage and cardiovascular events. We investigated prevalence and predictors of those blood pressure phenotypes in very elderly treated hypertensives. Design and method: Office blood pressure evaluation (simultaneous bilateral brachial blood pressure measurements in supine position and then after 2 minutes of standing) and 24-h ambulatory blood pressure monitoring (ABPM) were performed with a validated oscillometric cuff-based device iin 67 treated hypertensive subjects older than 80 years (mean age 84.1 ± 3.1 years, 25.5% male, mean office brachial SBP 134.8 ± 23.2 mm Hg). Patients with left ventricular ejection fraction < 40% and severe comorbidities were not included. Orthostatic hypotension (OH) was defined as a decrease in SBP of at least 20 mm Hg upon standing and orthostatic hypertension (OHT) as a corresponding increase. Results: The prevalence of MHT was 47.7% in the entire study population and 71.1% among patients with office-controlled hypertension (BP < 150/90 mm Hg). 78.2% patients with MHT had isolated nocturnal hypertension. Orthostatic reaction was abnormal in 34.3% subjects: 22.4% participants had OH while incidence of OHT was 11.9%. OHT was significantly associated with MHT (RR = 1.7, 95% CI = 1.14–2.78). Conclusions: OHT is predictive for MHT in the very elderly treated hypertensives. Evaluation of orthostatic reaction in very elderly may help to detect a population that would benefit from ABPM.

Longitudinal stability of the diurnal rhythm of intraocular pressure in subjects with healthy eyes, ocular hypertension and pigment dispersion syndrome.

BackgroundThe diurnal fluctuation of intraocular pressure may be relevant in glaucoma. The aim of this study was to find out whether the timing of diurnal fluctuation is stable over the years.MethodsLong-term IOP data from the Erlangen Glaucoma Registry, consisting of several annual extended diurnal IOP profiles for each patient, was retrospectively analyzed. Normal subjects, patients with ocular hypertension and with pigment dispersion syndrome were included because these subjects had not been treated with antiglaucomatous medications at the time of data acquisition. A cosine curve was fitted to the IOP data and the stability of individual rhythms over the years was tested using the Rayleigh test. To compare the peak times among groups, means were calculated only from subjects with a significant Rayleigh test.ResultsOf the fifty-two eligible subjects, a total of 364 extended diurnal IOP profiles measured in a sitting position had been collected over a period of 114 ± 39 months. The Rayleigh test indicated intraindividual stability of phase timing only in 19 subjects (36%). In subjects with pigment dispersions syndrome, peak IOP occurred on average two hours and seven minutes later during the day compared with subjects without this condition (p = 0.05).ConclusionsFitting of cosine curves to the clinical IOP profiles was generally feasible, although careful interpretation is warranted due to lack of measurements in supine position and between midnight and 7 am. The interesting observation of a phase lag in eyes with pigment dispersion syndrome warrants confirmation and exploration in future prospective studies. The analysis of the IOP data showed no stable individual rhythm in the long term in a majority of patients.

Lack of orthostatic symptoms in dementia patients with orthostatic hypotension.

Orthostatic hypotension (OH) is common and increases with age. OH is part of the autonomic dysfunction in dementia with Lewy bodies (DLB). Commonly OH is diagnosed when the patient falls which is a risk factor of premature death. Our objective was to systematically investigate the clinical symptoms associated with measurement of OH in different neurodegenerative dementias and normal controls (NC). 154 patients [50 DLB, 50 Alzheimer's disease (AD), 54 AD and vascular components (ADvasc)] were examined with systolic and diastolic blood pressure measurements in supine position, immediately after standing up and after 1, 3, 5 and 10 min of standing. They were compared with 50 NC. Orthostatic symptoms were registered according to a predefined protocol. Twenty-seven percent of all the investigated individuals reported OH symptoms during the measurement while 43% fulfilled the criteria of OH. Sixty-three percent of orthostatic patients did not have any symptoms during the measurement. The prevalence of any orthostatic symptoms during the measurement differed significantly (p < 0.001) between the diagnostic groups with 40% in DLB patients, 37% in ADvasc, 28% in AD and 2% in NC. The most frequent symptom was dizziness 13.7%. Classical orthostatic symptoms are absent in the majority of dementia patients with OH. The orthostatic reaction must therefore be routinely measured in this patient group. This is particularly important for patients with DLB where falls as a result of OH are common.

Development of protocols to estimate maximal oxygen consumption and body composition in individuals with spinal cord injury (884.27)

Cardiovascular complications and obesity are common secondary complications after spinal cord injury (SCI). The measurement of VO2max during graded exercise test is the gold standard to evaluate cardiovascular fitness. Due to the complexity and cost of VO2max measurements, regression equations to estimateVO2max from submaximal tests based on heart rate have been developed. Due to sympathetic impairments secondary to SCI heart rate may not be an accurate tool to use to predict VO2 max in SCI. The aim of this study was to validate a submaximal test based on Ratings of Perceived Exertion (RPE) to predict VO2max for people with SCI. A second aim of this study was to validate current skinfold equations to estimate percentage of body fat (%fat) in this population. Methods: 10 able‐bodied and 12 SCI individuals participated in this study. The standardized test protocols for VO2 max were performed on a total body recumbent stepper (NuStep T4 ergometer). Analysis of the expired gases occurred every 10 seconds. Heart rate was recorded using a Polar heart rate monitor and 3‐lead ECG. RPE was recorded using the Borg 6‐20 scale. Estimation of %fat by skinfold measurements in supine position were compared with values obtained by DXA scans. Results: There was a strong positive correlation between predicted and observed VO2max in able‐bodied subjects using RPE (ρ = 0.86; p蠄0.05) and RPE + watts (ρ = 0.88; p蠄0.05). SCI subjects were able to perform both, the maximal and submaximal protocols, with a cadence of 80 steps per minute. Current validated skinfolds equations underestimate %fat in SCI individuals. Conclusions: The results of this study show promise for the development of submaximal RPE‐based protocols for the prediction of VO2max in this population. Future directions include the examination of protocols ending at RPE 13 and RPE 15 as well as to develop prediction equations for a larger group of individuals with varying levels and severity of SCI. New prediction equations to estimate %fat for SCI need to be developed.

Determinants and reference values of short-term heart rate variability in children

This paper provides age- and sex-specific reference values for short-term heart rate variability (HRV) data in children by time domain and frequency domain methods. Furthermore, HRV determinants will be determined. In 460 children (5-10 years), 5-minute HRV measurements in supine position were undertaken with Polar chest belts. The data were manually edited and processed with time and frequency domain methods. Age, time point, physical activity (accelerometry), physical fitness (cardiopulmonary fitness, upper and lower limb muscular fitness) and body composition (body mass index, fat%, fat and fat-free mass) were analysed as determinants using multiple regression analysis stratified by sex. Sex- and age-specific reference values were produced. Overall, girls had lower HRV. Age-related parasympathetic increases and sympathetic decreases were seen with sometimes age-related year-to-year wave-like changes in boys. The time point of recording had limited influence on HRV. Of the lifestyle related factors, fatness (only 7 % overweight) was not associated with HRV but fat-free mass, physical activity and in particular physical fitness (over and above activity) had a favourable association by increased parasympathetic activity. Future HRV studies in children should consider age, sex and physical fitness.

42ndAnnual Conference: Effects of Traumatic Stress - Molecular and Hormonal Mechanisms

Rationale/ statement of the problem: Stress is a complex phenomenon coordinated by several neural systems and has consequently been measured by several biomarkers. Salivary cortisol is the classical used stress biomarker representing the hypothalamic-pituitary-adrenal system. Heart rate variability (HRV), defined as the distance variability between consecutive R peaks, is increasingly used as marker of the autonomic nervous system and as a result also as a stress marker (defined as sympathetic over parasympathetic dominance). Associations between children’s salivary cortisol and HRV will be examined. Methods: In 190 children (5-10 year) of the Belgian ChiBS study salivary cortisol and HRV were sampled. Salivary cortisol samples were collected when waking up, 30 minutes and 60 minutes after wake-up and in the evening on two weekdays. HRV measurements in supine position were undertaken with Polar chest belts during 5 minutes. Apart from HRV time-domain analysis, also frequency-domain analysis was performed in the low-frequency (LF) and high-frequency (HF) bands. Multilevel growth curve modelling with adjustments for age, sex, physical activity and wake-up time was used to analyse the HRV associations with overall cortisol, cortisol awakening response (CAR) and cortisol diurnal decline. Results: Higher overall cortisol levels were negatively associated with mean RR, root mean square of successive differences (RMSSD), percentage of RR intervals differing more than 5 0ms (pNN50) and HF. A steeper diurnal decline was positively associated with normalised LF and the LF/HF ratio and negatively with HF. The CARwas positively associated with normalised LF and the LF/HF ratio and negatively with normalised HF. Conclusion: Higher salivary cortisol levels were associated with lower parasympathetic activity. A larger CAR and steeper diurnal decline were associated with a sympathetic over parasympathetic dominance. Consequently, the two main neural stress systems (represented by cortisol and HRV) show good agreement in reflecting children’s stress status, although not all parameters were significantly related. Measuring both pathways stays recommended as the pathways might be stimulated differently depending on the stressor.

Inter-rater reliability of Rolimeter measurements between anterior cruciate ligament injured and normal contra lateral knees

The Rolimeter device can provide measurements of anterior/posterior tibial displacement using maximal manual force. The Rolimeter reliability is still under research when used as an independent knee tester. The purpose of this study is to determine the inter-rater reliability of the Rolimeter measurements between anterior cruciate ligament (ACL) injured and normal contra lateral knees. Twelve male patients with ACL deficiency participated in this study. Three physical therapists (PT) performed the Rolimeter measurements in supine position with an approximate 25 degrees flexion of the knees. Each therapist performed three trials on each knee and the difference in results in millimeters between injured knee and normal contra lateral knee was determined. Spearman's rho correlations showed weak relationships between the PT 1, 3 and 2, 3 (PT 1 vs. PT 3 r=0.55, PT 2 vs. PT 3 r=0.57) and the high relation between 1, 2 (PT 1 vs. PT 2 r=0.96) of Rolimeter measurements. Intraclass correlation coefficient showed no significant reliability coefficients among the three PT Rolimeter measurements between ACL injured and normal contra lateral knees (R=0.24, p=0.05). These results reflect the variations among the means of the three physical therapists' Rolimeter measurements between ACL injured and normal contra lateral knees.