PWV Values Research Articles

Arterial hypertension and pulse wave velocity

Abstract Aim. The purpose of the study is to identify the connection between high blood pressure and PWV in patients with AH and determine if AH is a risk factor that accelerates the development of atherosclerosis. Material and methods. With quantitative research method we investigated, explained, and defi ned the eff ects of arterial hypertension with the PWV increase‐rate observed across diff erent age groups of patients who already have AH. Data from patients’ medical records from the At Cor Sphygmocor operating system were extracted. Results. The sample included 191 patients with AH. PWV values were normal in 72% of patients with optimal blood pressure (BP), 60% of patients with normal BP had increased PWV in high normal BP and grade 1 AH were 53% of increased PWV, 53% of normal PWV in grade 2 AH, increased in 94% in grade 3 AH, and 50% of patients had increased PWV values in isolated systolic AH. Conclusions. The research results undoubtedly show the importance of arterial hypertension for the increase in pulse wave velocity, with the clearest correlation at grade 3 AH and in the age groups between 30 and 49 years. On average, the PWV value in hypertensive patients rose by 8%, which represents an increased risk of cardiovascular complications.

Dexamethasone-Induced Arterial Stiffening Is Attenuated by Training due to a Better Balance Between Aortic Collagen and Elastin Levels.

Although the cardioprotective benefits of exercise training are well known, the effects of training on dexamethasone (DEX)-induced arterial stiffness are still unclear. This study was aimed at investigating the mechanisms induced by training to prevent DEX-induced arterial stiffness. Wistar rats were allocated into 4 groups and submitted to combined training (aerobic and resistance exercises, on alternate days, 60% of maximal capacity, for 74 d) or were kept sedentary: sedentary control rats (SC), DEX-treated sedentary rats (DS), combined training control (CT), and DEX-treated trained rats (DT). During the last 14 d, rats were treated with DEX (50 μg/kg per body weight, per day, s.c.) or saline. DEX increased PWV (+44% vs +5% m/s, for DS vs SC, p<0.001) and increased aortic COL 3 protein level (+75%) in DS. In addition, PWV was correlated with COL3 levels (r=0.682, p<0.0001). Aortic elastin and COL1 protein levels remained unchanged. On the other hand, the trained and treated groups showed lower PWV values (-27% m/s, p<0.001) vs DS and lower values of aortic and femoral COL3 compared with DS. As DEX is widely used in several situations, the clinical relevance of this study is that the maintenance of good physical capacity throughout life can be crucial to alleviate some of its side effects, such as arterial stiffness.

Long-term changes in precipitable water vapour over India derived from satellite and reanalysis data for the past four decades (1980–2020)

PWV values are highest along the East Coast and lowest in the Western Himalaya. An increase in PWV is observed during the monsoon season, about 0.03–0.15 mm per year.

Increased arterial stiffness predict major adverse cardiovascular events in post-infarcted patients. Do parameters and methods matter?

Abstract Introduction According to recent 2021 ESC prevention guidelines arterial stiffness (aortic pulse wave velocity – PWV, augmentation index - Aix) predicts future major adverse cardiovascular events (MACE). Both parameters have a prognostic relevance, however due to the various technical approaches the level of high stiffness values show significant differences and resulting an argue against widespread use. Purpose We evaluated the cut-off PWV and Aix values for MACE prediction using cardiac magnetic resonance imaging (CMR) and oscillometric methods for validating the prognostic value of high stiffness parameters in post-infarcted patients. Methods CMR phase contrast imaging (Siemens Avanto, 1,5 T CMR device) and an invasively validated oscillometric based Arteriograph (AG) method were compared in this 6 years follow-up study, including 49 patients suffered previous ST-elevation myocardial infarction (STEMI). Patients received follow-up for MACE comprising all-cause death, non-fatal MI, ischemic stroke, hospitalization for heart failure and coronary revascularization. Results 49 patients (37 male, average age: 57±8 years) were investigated. An acceptable agreement and significant correlation (Spearman's rho: 0.332, p&amp;lt;0,01) was found between AG and CMR derived PWV values. Bland Altman plot was created to test for methods' agreement. The bias showed that in general the mean difference between the two measures was 3.6 m/s (upper and lower limit of agreement: –0.2 and 7.5 m/s). The coefficient of variation was 43.9%. Totally 51 MACE events occurred during the 6 years follow-up period. Hospitalisation for coronary revascularisation (55%), all-cause death (15%), non-fatal MI (12%), heart failure (12%) exposed the majority of MACE events. Optimized PWV and Aix cut-off values for MACE prediction were calculated (PWVCMR: 6,47 m/s; PWVAG: 9,625 m/s; AixAG: 34,22%) by receiver operating characteristic analysis (Figure 1). Kaplan-Meier analysis in all parameters showed a significantly lower event-free survival in case of high PWV and Aix values (Figure 2). Multivariate Cox regression analysis revealed PWV and Aix as a predictor of MACE (PWVCMR hazard ratio (HR): 1.31 (CI: 1.1–1.7), PWVAG HR: 1.24 (CI: 1.0–1.5), AixAG HR: 1,043 (CI: 1,01–1,08), p&amp;lt;0,05 respectively). Conclusions Arterial stiffness, particularly elevated PWV predicts MACE in postinfarcted patients. Our study showed both CMR and oscillometric techniques are feasible for MACE prediction, however, adjusted cut-off values of PWV are recommended for different methods to improve individual risk stratification. All these findings emphasize the clinical relevance for the future measurement of arterial stiffness might contribute to improved risk stratification after MI, which is crucial for the assessment of prognosis and guidance of secondary prevention treatment. Funding Acknowledgement Type of funding sources: None.

A Combined Linear–Nonlinear Short-Term Rainfall Forecast Method Using GNSS-Derived PWV

Short-term rainfall forecast using GNSS-derived tropospheric parameters has gradually become a research hotspot in GNSS meteorology. Nevertheless, the occurrence of rainfall can be attributed to the impact of various weather factors. With only using tropospheric parameters retrieved from GNSS (such as ZTD or PWV) for linear forecast, it could be challenging to describe the process of rainfall occurrence accurately. Unlike traditional linear algorithms, machine learning can construct better the relationship between various meteorological parameters and rainfall. Therefore, a combined linear–nonlinear short-term rainfall forecast method is proposed in this paper. In this method, the PWV time series is first linearly fitted using least squares, and rainfall events are determined based on the PWV value, PWV variation, and PWV variation rate. Then, a support vector machine (SVM) is used to establish a nonlinear rainfall forecasting model using the PWV value, air temperature, air pressure, and rainfall. Finally, the previous two rainfall forecast methods are combined to obtain the final rainfall event. To evaluate the accuracy of the proposed method, experiments were conducted utilizing the temperature, pressure, and rainfall data from ERA5. The experimental results show that, compared to existing short-term rainfall forecast models, the proposed method could significantly lower the false alarm rate (FAR) of rainfall forecasts without compromising the true detection rate (TDR), which were 26.33% and 98.66%, respectively. In addition, the proposed method was verified using measured GNSS and meteorological data from Yunmao City, Guangdong, and the TDR and FAR of the verified results were 100% and 20.2%, respectively, which were proven to apply to actual rainfall forecasts.

VASCULAR OR CARDIAC? DIFFERENT TARGET ORGAN DAMAGE IN HYPERTENSIVE PATIENTS WITH OR WITHOUT CHRONIC KIDNEY DISEASE

Objective: The aim of our study was to evaluate different types of target organ damage (TOD) in hypertensive patients, with or without chronic kidney disease (CKD). Design and method: 90 hypertensive patients were enrolled from our Hypertension Center: 48 with normal renal function and 42 with CKD. We performed a complete echocardiographic study in all subjects in order to evaluate cardiac damage; non-mydriatic digital fundus oculi examination and carotid-femoral PWV to assess, respectively, small vessels and large arteries alterations. We considered Left Ventricular Mass index (LVMi) and h/r index to determine Left Ventricular Hypertrophy (LVH) or remodeling, Arteriolar-Venular Ratio (AVR) to evaluate retinal vessels and carotid-femoral PWV as a measure of arterial stiffness. Results: Both groups showed abnormal values of PWV, but significantly higher in CKD group (13.72 ± 1.3 vs 9.78 ± 0.491, p = 0.0166). Mean AVR values were abnormal only in CKD hypertensive, with a significant difference compared to simply hypertensive patients (0.75 ± 0.006 vs 0.84 ± 0.020, p = 0.0001). In the echocardiographic examination, no statistically significant alterations were found between the two groups (LVMi 118.04 ± 4.870 vs 113.42 ± 3.440, p = 0.123; h/r 0.42 ± 0.119 vs 0.44 ± 0.010, p = 0.454). Conclusions: Our results confirm that TOD is different in hypertensive patients with CKD. In these patients the target is essentially vascular, affecting either big and small vessels. Hypertensive patients without CKD showed a more typical cardiac TOD with an increase of left ventricular remodeling and hypertrophy. The assessment of vascular damage pays an essential role in TOD detection, so the use of PWV and the evaluation of retinal vessels should be always performed.

Швидкість розповсюдження пульсової хвилі у хворих на гіпертонічну хворобу залежно від категорії кардіоваскулярного ризику

У роботі доведено доцільність індивідуальної оцінки швидкості розповсюдження пульсової хвилі з урахуванням віку і рівня артеріального тиску для своєчасного виявлення раннього судинного старіння. У чоловіків, хворих на ГХ, вже при І стадії із помірним серцево-судинним ризиком спостерігається погіршення пружно-еластичних властивостей артеріальної стінки. Із збільшенням стадії захворювання та категорії серцево-судинного ризику встановлено прогресуюче підвищення ШРПХ.

Accuracy of a new instrument for noninvasive evaluation of pulse wave velocity: the Arterial sTiffness faitHful tOol aSsessment project.

Large artery stiffness, assessed by carotid--femoral pulse wave velocity (cfPWV), is a major risk factor for cardiovascular events, commonly used for risk stratification. Currently, the reference device for noninvasive cfPWV is SphygmoCor but its cost and technically challenging use limit its diffusion in clinical practice. To validate a new device for noninvasive assessment of cfPWV, ATHOS (Arterial sTiffness faitHful tOol aSsessment), designed in collaboration with the Politecnico di Torino, against the reference noninvasive method represented by SphygmoCor. Ninety healthy volunteers were recruited. In each volunteer, we assessed cfPWV, using SphygmoCor (PWVSphygmoCor) and ATHOS (PWVATHOS) devices in an alternate fashion, following the ARTERY Society guidelines. The accuracy was assessed by Bland--Altman plot, and reproducibility was assessed by interoperator correlation coefficient (ICC). Mean PWVATHOS and mean PWVSphygmoCor were 7.88 ± 1.96 and 7.72 ± 1.95 m/s, respectively. Mean difference between devices was 0.15 ± 0.56 m/s, with a high correlation between measurements (r = 0.959, P < 0.001). Considering only PWV values at least 8 m/s (n = 30), mean difference was 0.1 ± 0.63 m/s. The ICC was 97.7% with ATHOS. ATHOS showed an excellent level of agreement with SphygmoCor, even at high PWV values, with a good reproducibility. Its simplicity of use could help increase clinical application of PWV assessment, improving patients' cardiovascular risk stratification.

АRTERIAL STIFFNESS AND CENTRAL AORTAL PRESSURE AS SIGNIFICANT PREDICTORS OF COMPLICATIONS AFTER OFF-PUMP CORONARY ARTERY BYPASS GRAFTING

Some studies have shown that an increase in arterial stiffness and central aortic pressure increase the risk of postoperative complications for off-pump coronary artery bypass grafting (off-pump CABG). AIM: To determine the significance of arterial stiffness and central aortic pressure indicators for predicting acute kidney injury (AKI) and cardiac events in patients after off-pump CABG. MATERIALS AND METHODS: An analysis of off-pump CABG outcomes was carried out in 196 patients (mean age 62.7 ± 5.3 years) without clinical signs of chronic kidney disease. The patients were divided into a test (n = 56) and control (n = 140) groups, depending on the presence or absence of AKI, acute coronary syndrome (ACS), or cardiac arrhythmias in the early postoperative period. Pulse wave velocity indicators (PWV) were processed on the carotidfemoral (cf PWV) and brachio-ankle (baPWV) segments, and the results of measuring central aortic pressure (CAP). RESULTS: It has been proven that the incidence of AKI is significantly higher in patients with higher cf PWV (n &lt;0.001), baPWV (n = 0.034) and systolic aortic pressure (SAP) (n = 0.013). ACS was more often observed in patients with higher SAP (n &lt;0.001) and diastolic (DAP) (n = 0.005) aortic pressure, and cardiac arrhythmias in patients with higher SAP and office systolic pressure (n &lt; 0.001). Based on the results of logistic regression analysis, it was determined (by regression coefficients — B) that an increase in cf PWV by 1 m/s increases the risk of AKI by 85.0%. An increase in SAP by one unit significantly increases the risk of ACS by 111.0% and cardiac arrhythmias by 58.0%. It was shown that the measurement of CAP has a greater diagnostic value than the office measurement of blood pressure. CONCLUSION: Arterial stiffness is an independent predictor of AKI for off-pump CABG. A decrease in PWV value is accompanied by a decrease in the incidence of AKI. CAP indices have a more significant prognostic value with respect to the likelihood of cardiac events after an off-pump CABG than the data of measurement of blood pressure.

Evaluation of Hourly PWV Products Derived From ERA5 and MERRA‐2 Over the Tibetan Plateau Using Ground‐Based GNSS Observations by Two Enhanced Models

AbstractPrecipitable water vapor (PWV), despite being the key factor for assessing climate change over the Tibetan Plateau (TP), is undersampled in this region due to the complex terrain and climate conditions therein. The fifth‐generation European Center for Medium‐Range Weather Forecasts Reanalysis (ERA5) and Second Modern‐Era Retrospective Analysis for Research and Applications (MERRA‐2) data sets are the two newly released global reanalyzes that provide hourly PWV products with a high spatiotemporal resolution for water vapor research. The accuracies of these two PWV products on the TP require a comprehensive and cautious assessment. In this study, the hourly PWV values derived from ERA5 and MERRA‐2 are systematically assessed by a comparison with 33 Global Navigation Satellite System (GNSS) stations from 2017 to 2018 over the TP. To improve the reliability of this evaluation, an enhanced Tm model and a PWV vertical correction model, namely, TP‐Tm and TP‐PWVC, respectively, are developed, and both models show better performance when compared against other widely used models. The accuracies of the ERA5‐ and MERRA‐2‐derived PWV at the 33 GNSS stations are very high; ERA5 has the smallest mean bias and root mean square (RMS) error of −0.08 and 1.77 mm, respectively, compared to those of 0.53 and 2.12 mm for MERRA‐2. In addition, the biases and RMS errors show significant regional and seasonal differences. The performance of ERA5 is slightly better than MERRA‐2, mainly due to its higher spatial resolution. The spatial distributions of the PWV derived from the two reanalyzes are consistent with the GNSS‐derived PWV distribution. The diurnal PWV variations derived from ERA5 are in good agreement with the diurnal variation of the GNSS‐derived PWV, whereas significant differences are observed for MERRA‐2 at several stations. These results indicate that ERA5 can provide more reliable hourly PWV estimates over the TP, which can help users further understand the strengths and weaknesses of these two PWV products and promote climate change research.

Global Comparisons of ERA5 and the Operational HRES Tropospheric Delay and Water Vapor Products With GPS and MODIS

AbstractPrecipitable water vapor (PWV) from numerical weather models, such as the latest generation of European Centre for Medium‐Range Weather Forecasts (ECMWF) reanalysis (ERA5) and the ECMWF High RESolution (HRES) models, are important to meteorological studies and to error mitigation of geodetic observations such as Interferometric Synthetic Aperture Radar. In this study, we provide global validations of these new weather models with respect to Global Positioning System (GPS, ∼13,000 stations) and Moderate Resolution Imaging Spectrometer (MODIS, ∼1 km resolution) using data from January 2016 to December 2018 of every 1 h. The global standard deviations of the Zenith Tropospheric Delay (ZTD) differences (DSTDs) between weather models and GPS are 1.69 cm for ERA5 and 1.54 cm for HRES. The global PWV DSTDs between weather models and MODIS are 0.34 cm for ERA5 and 0.32 cm for HRES. The two weather models generally perform better in western North America, Europe, and Arctic by having low ZTD DSTDs (&lt;1.3 cm) or PWV DSTDs (&lt;0.3 cm). HRES also has a low ZTD DSTD of less than 1.3 cm in Antarctic, Japan, New Zealand, and Africa and outperforms ERA5 in most regions of the world, despite the fact that 83% of the HRES PWV values are temporally interpolated (from 6 to 1‐h). However, under extreme weather conditions, ERA5 performs better owing to its high temporal resolution (1 h). Our results can be used as a global reference for evaluating uncertainties when utilizing these weather models.

METEOROLOGICAL GNSS APPLICATION FOR HEAVY RAIN ON DECEMBER 31, 2019 IN THE JAKARTA AND SURROUNDING AREAS

This study aims to utilize GNSS for meteorology in Indonesia. With the "goGPS" software, the zenith troposphere delay (ZTD) value is estimated. Calculations in rainy conditions, the ZTD value is converted into a water vapor value (PWV). The research area for the phenomenon of heavy rain occurred at the end of 2019 in Jakarta and its surroundings, which caused flooding on January 1, 2020. According to the Geophysical Meteorology and Climatology Agency (BMKG), the flood's primary cause was high rainfall. Meanwhile, the rainfall at Taman Mini and Jatiasih stations was 335 mm/day and 260 mm/day, respectively. We get an interesting pattern of PWV values for this rain phenomenon. GNSS data processing, the PWV value at five GNSS stations around Jakarta, shows the same pattern even though the average distance between GNSS stations is ~ 30 km. The PWV value appears to increase at noon on December 30, 2019, and the peak occurs in the early hours of December 31, 2019. The PWV value suddenly decreases at noon on January 1, 2020. Next, the PWV value increases again but not as high as at the previous peak. Since January 2, 2020, the PWV value has decreased and remained almost constant until January 4, 2020. In that period, there were two events that the PWV value increased. The PWV value at the first peak is ~ 70 mm, and at the second peak ~ 65 mm. The most significant increase in PWV value was recorded at CJKT stations.

Probing the Atmospheric Precipitable Water Vapor with SOFIA. II. Atmospheric Models from ECMWF

SOFIA is an airborne observatory for far-infrared astronomy. Although SOFIA flies at altitudes of ∼41,000 feet, any far-infrared observations from within the Earth’s atmosphere are nevertheless hampered by water vapor absorbing the astronomical signal. The atmospheric parameter governing absorption is the total upward precipitable water vapor, PWV. In this paper we investigated if data of the Earth’s atmosphere provided by the European Centre for Medium-Range Weather Forecasts, ECMWF, can be used to determine spatially and time-resolved PWV data to allow a more precise calibration of far-infrared data taken with SOFIA along its flight path. We found that PWV values obtained from ECMWF correlate extremely well with independently determined PWV values obtained with the FIFI-LS instrument onboard SOFIA. We determined maximum observing time intervals (depending on the pressure altitude SOFIA is flying at) within which the upward PWV value changes inflight by less than a certain amount. We also present a new calibration method which enhances data quality and observing efficiency with FIFI-LS significantly. Furthermore our new method is universal and may be applied to data from all of SOFIA's instruments.

EXTERNAL VALIDATION STUDY OF THE EARLY VASCULAR AGING AMBULATORY SCORE (EVAAS)

Objective: The Early Vascular Aging Ambulatory score (EVVAs) identify hypertensive patients with Early Vascular Aging using ambulatory blood pressure monitoring values and classic cardiovascular risk factors. Our aim was to validate the EVAAs externally in a new population-based cohort study. Design and method: This cohort study included all consecutive patients (N = 789, 45.87 ± 23.27, 45.4% men), who referred to the Hypertension-24hour Ambulatory Blood Pressure Monitoring Center of Excellence, at the 3rd Internal Medicine Department of Aristotle University for elevated BP and consented to participate to the study. Carotid-femoral pulse wave velocity (c-f PWV) was measured in all patients. EVA was defined as c-f PWV values higher than the expected for age average values according to European population data. We evaluated the predictive power of the original EVVAs. Results: The calculated sensitivity and specificity for EVAAS was 98% and 75% respectively. The EVVAs has a high positive predictive value (PPV) of 95%. The negative predictive value (NPV) was slightly lower at 92%. Receiver operating characteristic curve, including the area under the curve, was 0.951 which indicates a very high accuracy. Conclusions: The external validation of the EVVAs yields high sensitivity and PPV in an independent population. The EVAAs should now be evaluated for its predictive value regarding cardiovascular mortality and morbidity. Finally, the prediction of EVA, assessed by EVAAs, could be used to guide early lifestyle or pharmaceutical interventions in order to prevent future CV events.

THE IMPACT OF MASKED HYPERTENSION ON ARTERIAL STIFFNESS: A SYSTEMATIC REVIEW AND META-ANALYSIS

Objective: Arterial stiffness, expressed by carotid-femoral pulse wave velocity (c-f PWV), is recognized as independent predictor for future cardiovascular disease. The aim of this study was to investigate for the first time the impact of masked hypertension (MH) on c-f PWV, in untreated patients. Design and method: PubMed and Cochrane Library were searched systematically to identify studies comparing c-f PWV levels between normotensives, hypertensives, and MH. Meta-analysis was performed to compare the difference c-f PWV levels between these groups. New Castle Ottawa quality assessment scale for case-control studies was used to assess study quality. Results: MH patients had significantly increased c-f PWV values compared to the normotensive groups (d = 0.95, 95% CI: 0.42 to 1.48, P &lt; 0.01). Moreover, the hypertensive population was found to have statistically significant increased values of c-f PWV compared to MH (d = -0.74, 95% CI: -0.96 to - 0.52, P = 0.18). Finally, there was no statistically significant difference between MH and white coat hypertension population (d = 0.06, 95% CI: -1.04 to 1.15, P &lt; 0.001). Conclusions: MH population have statistically significant increased values of c-f PWV compared to the normotensive group. These results demonstrate the severity of MH and the importance of evaluating blood pressure with out-of-office measurements in the untreated population.

WHITE COAT HYPERTENSION AND ARTERIAL STIFFNESS: A SYSTEMATIC REVIEW AND META-ANALYSIS

Objective: Arterial damage of large arteries, addressed as carotid-femoral pulse wave velocity (c-f PWV), is recognized as independent predictor for future cardiovascular disease. The aim of this study was to investigate the impact of white coat hypertension on c-f PWV, in an untreated population. Design and method: PubMed and Cochrane Library were searched systematically to identify studies comparing c-f PWV levels between normotensives, hypertensives and white-coat hypertensives (WCH). Meta-analysis was performed to compare the difference c-f PWV levels between these groups. New Castle Ottawa quality assessment scale for case-control studies was used to assess study quality. Results: WCH patients had significantly increased c-f PWV values compared to the normotensive groups (d = 0.87 95% CI: 0.52 to 1.21, P &lt; 0.01). Moreover, the hypertensive population was found to have statistically significant increased values of c-f PWV compared to WCH population (d = -0.74, 95% CI: -1.43 to -0.05, P &lt; 0.01). Finally, there was no statistically significant difference between masked hypertension and WCH population (d = 0.06, 95% CI: -1.04 to 1.15, P &lt; 0.001). Conclusions: WCH population have statistically significant increased values of c-f PWV compared to the normotensive group. These results demonstrate that WCH is not clinically innocent, in the untreated population.

Arterial stiffness in acute COVID-19 and potential associations with clinical outcome.

BackgroundCoronavirus disease 2019 (COVID‐19) interferes with the vascular endothelium. It is not known whether COVID‐19 additionally affects arterial stiffness.MethodsThis case–control study compared brachial‐ankle pulse wave (baPWV) and carotid‐femoral pulse wave velocities (cfPWV) of acutely ill patients with and without COVID‐19.ResultsTwenty‐two COVID‐19 patients (50% females, 77 [67–84] years) were compared with 22 age‐ and sex‐matched controls. In COVID‐19 patients, baPWV (19.9 [18.4–21.0] vs. 16.0 [14.2–20.4], P = 0.02) and cfPWV (14.3 [13.4–16.0] vs. 11.0 [9.5–14.6], P = 0.01) were higher than in the controls. In multiple regression analysis, COVID‐19 was independently associated with higher cfPWV (β = 3.164, P = 0.004) and baPWV (β = 3.532, P = 0.003). PWV values were higher in nonsurvivors. In survivors, PWV correlated with length of hospital stay.ConclusionCOVID‐19 appears to be related to an enhanced PWV reflecting an increase in arterial stiffness. Higher PWV might be related to an increased length of hospital stay and mortality.

Water Vapor Retrievals from Spectral Direct Irradiance Measured with an EKO MS-711 Spectroradiometer—Intercomparison with Other Techniques

Precipitable water vapor retrievals are of major importance for assessing and understanding atmospheric radiative balance and solar radiation resources. On that basis, this study presents the first PWV values measured with a novel EKO MS-711 grating spectroradiometer from direct normal irradiance in the spectral range between 930 and 960 nm at the Izaña Observatory (IZO, Spain) between April and December 2019. The expanded uncertainty of PWV (UPWV) was theoretically evaluated using the Monte-Carlo method, obtaining an averaged value of 0.37 ± 0.11 mm. The estimated uncertainty presents a clear dependence on PWV. For PWV ≤ 5 mm (62% of the data), the mean UPWV is 0.31 ± 0.07 mm, while for PWV &gt; 5 mm (38% of the data) is 0.47 ± 0.08 mm. In addition, the EKO PWV retrievals were comprehensively compared against the PWV measurements from several reference techniques available at IZO, including meteorological radiosondes, Global Navigation Satellite System (GNSS), CIMEL-AERONET sun photometer and Fourier Transform Infrared spectrometry (FTIR). The EKO PWV values closely align with the above mentioned different techniques, providing a mean bias and standard deviation of −0.30 ± 0.89 mm, 0.02 ± 0.68 mm, −0.57 ± 0.68 mm, and 0.33 ± 0.59 mm, with respect to the RS92, GNSS, FTIR and CIMEL-AERONET, respectively. According to the theoretical analysis, MB decreases when comparing values for PWV &gt; 5 mm, leading to a PWV MB between −0.45 mm (EKO vs. FTIR), and 0.11 mm (EKO vs. CIMEL-AERONET). These results confirm that the EKO MS-711 spectroradiometer is precise enough to provide reliable PWV data on a routine basis and, as a result, can complement existing ground-based PWV observations. The implementation of PWV measurements in a spectroradiometer increases the capabilities of these types of instruments to simultaneously obtain key parameters used in certain applications such as monitoring solar power plants performance.

Auto-adaptive positive airway pressure improves lung function and arterial stiffness parameters in patients with severe obstructive sleep apnea syndrome over a 1 year follow-up

Objective: Auto-adaptive positive airway pressure (APAP) is an emerging therapeutic modality for obstructive sleep apnea (OSA) patients. However, their associated physiological effects have not been well-defined. Therefore, we aimed to investigate the impact of a 1 year APAP treatment on lung function and arterial stiffness parameters. Approach: This study enrolled male patients with newly diagnosed severe OSA who have undergone APAP treatment. A total of 35 patients completed a 1 year follow up. Blood pressure, arterial stiffness (PWV, cAIx, pAIx, cSBP), and lung function readings (FEV1, FVC, FEV1/FVC, PEF) were obtained basally and after 1, 3, 6, and 12 months of treatment. Main results: A gradual increase in FEV1 has been observed over the follow-up (2.92 ± 0.88 versus 3.07 ± 0.92 versus 3.18 ± 0.93 versus 3.28 ± 0.93 versus 3.41 ± 0.97 L), while PWV showed a gradual decrease over the follow-up (9.72 ± 1.64 versus 9.32 ± 1.73 versus 8.89 ± 1.65 versus 8.53 ± 1.61 versus 8.46 ± 1.60 m s−1), as measured by absolute values. Linear mixed effects model analysis revealed a statistically significantly higher FEV1 values (coefficient of 0.11, 0.20, and 0.33 for 3rd month, 6th month, and 12th month, respectively, P < 0.001) and lower PWV values (coefficient of −0.69, −0.63, and −0.34 for 3rd month, 6th month, and 12th month, respectively, P < 0.001), after the initiation of APAP treatment. Significance: We conclude that APAP treatment improves main lung function and arterial stiffness parameters in male patients with severe OSA over a 1 year follow-up.

Increased pulse wave velocity strongly related to age in apparently healthy people of high cardiovascular risk population

Abstract Introduction Pulse wave velocity (PWV) as a measure of arterial stiffness is associated with CVD morbidity and mortality. CVD mortality rates show Estonia (capital Tallinn) as being among high cardiovascular (CV) risk countries. Our study aimed to investigate the prevalence of increased PWV in Tallinn adults aged 20–65, apparently healthy (AH) at primary medical examination, and also to evaluate the association of increased PWV with age and biochemical cardiovascular risk factors at levels indicative of CV risk. Methods PWV measured by Arteriograph and biochemical CV risk factors by Cobas Roche 6000 analyzer were investigated in 805 responders of a cross-sectional population-based study of Tallinn adults aged 20–65, randomly selected from the Estonian Population Register by age decade and sex. Apparently healthy conditions were defined at primary visit as absence of hypertension (SBP &amp;lt;140 and DBP &amp;lt;90 mmHg), diabetes, obesity (BMI &amp;lt;30 kg/m2), a history of known heart disease and medication usage against hyperlipidaemia. Statistical analysis was performed by MedCalc version 14.8.1. Results 445 people (men=180, women=265) were in AH conditions with median values (95% central range) of SBP, DBP, and BMI: 115 (94–137) mmHg, 73 (55–87) mmHg, and 24 (18–29) kg/m2. 27.4% of AH adults were smokers. Medians (95% central range) and indicative of CV risk level (with crude prevalence at this level) of other investigated CV risk factors were: PWV 6.2 (4.5–11.3), ≥9.7 m/s (24.7%); age 39 (23–62), ≥50 years (24.7%); total cholesterol 5.2 (3.7–7.2), &amp;gt;5.0 mmol/L (57.1%); triglycerides 1.0 (0.5–2.7), ≥1.7 mmol/L (14.8%); apolipoprotein B 3.0 (1.7–4.7), &amp;gt;2.6 /2.3 μmol/L for men/women (76.6%); HDL cholesterol 1.6 (1.0–2.6), &amp;lt;1.0/1.3 mmol/L for men/women (7.0%); LDL cholesterol 3.2 (1.7–5.2), ≥3.0 mmol/L (82.7%); homocysteine 11.8 (7.1–20.2), ≥12.0 μmol/L (49%); lipoprotein (a) 0.1 (0.1–1.2), &amp;gt;0.3 g/L (23.6%); high-sensitivity C-reactive protein 0.9 (0.2–6.8), &amp;gt;3.0 mg/L (10.1%). Categorization of PWV values as indicative of CV risk (increased PWV) was made according to their interpretation by Arteriograph software as increased or abnormal. Stepwise logistic regression analysis of increased PWV along with age and biochemical risk factors revealed statistically significant and strong association only with age ≥50. Overall model fit p was &amp;lt;0.0001, c-statistic 0.838, odds ratio 29.3. Conclusions Despite total cholesterol, apolipoprotein B, LDL cholesterol and homocysteine being at indicative of CV risk level in over 50% of AH people, increased PWV was observed only in about 6% of them. The study showed that being 50 years of age or older in a high risk population means 29 times greater probability of increased arterial stiffness than in younger ages, even without having hypertension, diabetes or obesity. This knowledge is important for preventive CVD strategy in this population group. Funding Acknowledgement Type of funding source: Public grant(s) – National budget only. Main funding source(s): Estonian Ministry of Education and Research under institutional research financing