Prevalence of interarm blood pressure difference is notably higher in women; the Viborg population-based screening program (VISP).

BACKGROUND: Bilateral blood pressure (BP) measurement is important in cardiovascular prevention for identifying systolic interarm BP difference (IAD) and hypertension. We investigated sex-stratified IAD prevalence and its associations and coexistence with screen-detected peripheral atherosclerosis and hypertension. Furthermore, we determined the proportion misclassified as non-hypertensive when using the lower versus the higher reading arm. METHODS: This sub-study formed part of the Viborg Screening Program (VISP), a cross-sectorial population-based cardiovascular screening programme targeting 67-year-old Danes. VISP includes screening for peripheral atherosclerosis (lower extremity arterial disease and carotid plaque), abdominal aortic aneurysm, hypertension, diabetes mellitus, and cardiac disease. Self-reported comorbidities, risk factors, and medication use were also collected. Among 4,602 attendees, 4,517 (82.1%) had eligible bilateral and repeated BP measurements. IAD was defined as a systolic BP difference ≥ 10 mmHg. IAD-associated factors (screening results and risk factors) were estimated by logistic regression; proportional coexistence was displayed by Venn diagrams (screening results). RESULTS: We included 2,220 women (49.2%) and 2,297 men (50.8%). IAD was more predominant in women (26.8%) than men (21.0%) (p < 0.001). This disparity persisted after adjustment [odds ratio (OR) 1.53; 95% confidence interval (CI) 1.32-1.77]. No other association was recorded with the conditions screened for, barring potential hypertension: BP 140-159/90-99 mmHg (OR 1.68, 95% CI 1.44-1.97) and BP ≥ 160/100 mmHg (OR 1.82, 95% CI 1.49-2.23). Overall, IAD and BP ≥ 160/100 mmHg coexistence was 4% in women and 5% in men; for BP ≥ 140/90 mmHg, 13% and 14%, respectively. Among those recording a mean BP ≥ 140/90 mmHg in the higher reading arm, 14.5% of women and 15.3% of men would be misclassified as non-hypertensive compared with the lowest reading arm. CONCLUSION: Female sex was an independent factor of IAD prevalence but not associated with other arterial lesions. Approximately 15% needed reclassification according to BP ≥ 140/90 mmHg when the lower rather than the higher reading arm was used; verifying bilateral BP measurements improved detection of potential hypertension. In future, the predictive value of sex-stratified IAD should be assessed for cardiovascular events and death to verify its potential as a screening tool in population-based cardiovascular screening. TRIAL REGISTRATION FOR VISP: NCT03395509:10/12/2018.

Association of interarm blood pressure difference with selected body circumferences among Walter Sisulu University community.

BACKGROUND: A high interarm blood pressure difference (IAD) has been identified as a precursor of vascular diseases. Anthropometric measures for obesity such as body circumferences including waist circumference (WC), mid-upper arm circumference (MUAC) and neck circumference (NC) have been associated with a high IAD in Western countries. However, the prevalence of IAD and its association with body circumferences in South African communities such as universities is not well established. Therefore, this study aimed at investigating the correlation of IAD with selected body circumferences among the Walter Sisulu University (WSU) community. METHODS: A total of 230 participants, 117 males and 113 females, consisting of 185 students and 45 staff members from WSU, aged 18-27 and 18-63 years respectively, participated in this cross-sectional study. The selected body circumferences: WC, MUAC, and NC were measured using standard procedures. Systolic blood pressure (SBP) and diastolic blood pressure (DBP) were measured in both arms simultaneously using automated machines. IAD was achieved by calculating differences in SBP and DBP between the left (L) and right (R) arms, (R -L), and getting the absolute value, L-R (|L-R|). RESULTS: 14.78% of the participants had an interarm SBP difference (IASBPD) ≥ 10 mmHg, and 4.35% of participants had an interarm DBP difference (IADBPD) ≥ 10 mmHg. In a Pearson's correlation analysis, IASBPD was positively correlated with the selected body circumferences (WC, r = 0.29; P < 0.001; MUAC, r = 0.35; P < 0.001; NC, r = 0.27; P < 0.001) and mean arterial pressure (MAP) (r = 0.30; P < 0.001). In the multivariable-adjusted regression analyses, IASBPD was positively associated with MUAC (adjusted R2 = 0.128, ß = 0.271 (95% CI = 0.09; 0.60), P = 0.008), and NC (adjusted R2 = 0.119, ß = 0.190 (95% CI = 0.01; 0.32), P = 0.032) only, adjusted for MAP, age, gender, body mass index, smoking, and alcohol. There was no association of body circumferences with IADBPD. CONCLUSION: A high IAD is common among students and staff members of the WSU community. Furthermore, IAD showed a positive correlation with MUAC and NC. These body circumferences can serve as indicators of high IAD, aiding in the early detection and prevention of vascular diseases.

Prevalence and factors associated with inter-arm systolic and diastolic blood pressure differences: results from the baseline Fasa Adult's Cohort Study (FACS).

BACKGROUND: One of the modifiable risk factors for cardiovascular diseases is the inter-arm blood pressure difference (IAD), which can be easily measured. This study aimed to determine the prevalence and factors related to the Iranian population's inter-arm differences in systolic and diastolic blood pressure. METHOD: This cross-sectional study was conducted on the baseline data of participants who had Iranian nationality, were at least 1 year of residence in the area, aged within the age range of 35-70 years, and willed to participate from the Fasa Persian Adult Cohort Study (FACS). IAD for systolic and diastolic blood pressure was measured and categorized into two groups of difference < 10 and ≥ 10 mmHg. Logistic regression was used to model the association between independent variables and IAD. RESULTS: The prevalence of systolic and diastolic IAD ≥ 10 mmHg was 16.34% and 10.2%, respectively, among 10,124 participants. According to the multivariable logistic regression models, age (adjusted odds ratio (aOR): 1.019 [95% CI: 1.013, 1.025]), body mass index (BMI) (aOR: 1.112 [95% CI: 1.016, 1.229]), having type 2 diabetes (aOR Yes/No: 1.172 [95% CI: 1.015, 1.368]), having chronic headaches (aOR Yes/No: 1.182 [95% CI: 1.024, 1.365]), and pulse rate (aOR: 1.019 [95% CI: 1.014, 1.024]) significantly increased the odds of systolic IAD ≥ 10 mmHg. Additionally, high socio-economic status decreased the odds of systolic IAD ≥ 10 mmHg (aOR High/Low: 0.854 [95% CI: 0.744, 0.979]). For diastolic IAD, age (aOR: 1.112 [95% CI: 1.015, 1.210]) and pulse rate (aOR: 1.021 [95% CI: 1.015, 1.027]) significantly increased the odds of diastolic IAD ≥ 10 mmHg. Moreover, high socioeconomic status decreased the odds of diastolic IAD ≥ 10 mmHg (aOR High/Low: 0.820 [95% CI: 0.698, 0.963]). CONCLUSION: The noticeable prevalence of systolic and diastolic IAD in general population exhibits health implications due to its' association with the risk of cardiovascular events. Sociodemographic and medical history assessments have potentials to be incorporated in IAD risk stratification and preventing programs.

Inter-leg systolic blood pressure difference has been associated with all-cause and cardiovascular mortality: analysis of NHANES 1999-2004.

BACKGROUND: Inter-leg systolic blood pressure difference (ILSBPD) has emerged as a novel cardiovascular risk factor. This study aims to investigate the predictive value of ILSBPD on all-cause and cardiovascular mortality in general population. METHODS: We combined three cycles (1999-2004) of the National Health and Nutrition Examination Survey (NHANES) data. Levels of ILSBPD were calculated and divided into four groups based on three cut-off values of 5, 10 and 15mmHg. Time-to-event curves were estimated with the use of the Kaplan-Meier method, and two multivariable Cox proportional hazards regression models were conducted to assess the hazard ratios (HRs) and 95% confidence intervals (CIs) of all-cause and cardiovascular mortality associated with ILSBPD. RESULTS: A total of 6 842 subjects were included, with the mean (SD) age of 59.5 (12.8) years. By December 31, 2019, 2 544 and 648 participants were identified all-cause and cardiovascular mortality respectively during a median follow-up of 16.6 years. Time-to-event analyses suggested that higher ILSBPD was associated with increased all-cause and cardiovascular mortality (logrank, p < 0.001). Every 5mmHg increment of ILSBPD brings about 5% and 7% increased risk of all-cause and cardiovascular mortality, and individuals with an ILSBPD ≥ 15mmHg were significantly associated with higher incidence of all-cause mortality (HR 1.43, 95%CI 1.18-1.52, p < 0.001) and cardiovascular mortality (HR 1.73, 95%CI 1.36-2.20, p < 0.001) when multiple confounding factors were adjusted. Subgroup and sensitivity analysis confirmed the relationship. CONCLUSIONS: Our findings suggest that the increment of ILSBPD was significantly associated with higher risk of all-cause and cardiovascular mortality in general population.

Sensitive detection of hemodynamic changes after fetoscopic laser photocoagulation by assessing intraventricular pressure difference in fetuses with twin-to-twin transfusion syndrome.

OBJECTIVES: To assess the hemodynamics of twin-to-twin transfusion syndrome (TTTS), we measured the intraventricular pressure difference (IVPD), a sensitive marker of myocardial diastolic function, using fetal echocardiography. METHODS: We included 28 monochorionic diamniotic (MD) twins diagnosed with TTTS who underwent fetoscopic laser photocoagulation (FLP) between 2018 and 2022. Color M-mode Doppler images of both cardiac ventricles were obtained before and after FLP. According to this evaluation, the IVPDs were divided into three groups; those with total, basal, and mid-apical IVPD. RESULTS: Of the 28 twins, 21 were available for analysis (including eight, eight, three, and two cases in stages Quintero Ⅰ, Ⅱ, Ⅲd, and Ⅲr, respectively). Comparing the pre and postFLP results, significant increases in total and mid-apical IVPD in the left ventricle (LV) of recipient twins were noted (total and mid-apical IVPD: p=0.026 and 0.013, respectively). In the LV of the donor twins, all IVPDs were significantly increased after FLP (total, basal, and mid-apical IVPD: p=0.003, 0.001, and 0.022, respectively). In addition, comparisons between the donor and recipient groups did not show significant differences in either ventricle before FLP. CONCLUSIONS: IVPD detected subtle hemodynamics changes, such as volume overload and diastolic dysfunction in TTTS before and after FLP. Therefore, IVPD may be a useful marker for monitoring myocardial diastolic function in TTTS.

The Predictive Value of Inter Arm Blood Pressure Difference, Inter Leg Blood Pressure Difference and Ankle Brachial Index for Acute Aortic Dissection.

Introduction: Abnormal inter arm systolic blood pressure, inter leg systolic blood pressure and ankle brachial index (ABI) are related to vascular diseases. Our aim was to evaluate the correlation of inter arm systolic blood pressure difference (IASBPD), inter leg systolic blood pressure difference (ILSBPD), and ABI with acute aortic dissection (AAD) and their role in predicting AAD. Methods: In this prospective case-control study, 180 patients with AAD admitted to the emergency department were prospectively and consecutively collected in Tongji Hospital from October 2019 to December 2020. 180 healthy people matched by sex, age and BMI served as control group. All participants were adults over 18 years of age who underwent four-limb blood pressure measurements. IASBPD, ILSBPD and ABI were compared between the two groups and their associations with AAD were analyzed. Results: A total of 360 patients (180 cases and 180 controls) were analyzed. In case group IASBPD was larger [(15.23 ± 16.15) mm Hg vs. (4.19 ± 3.63) mm Hg] and ILSBPD was larger (13.00 mm Hg vs. 5.70 mm Hg). ABI was smaller [(0.98 ± 0.24) vs. (1.12 ± 0.09)], and the difference was statistically significant (all p < 0.05). According to the receiver operating characteristic curve (ROC), IASBPD ≥ 10 mm Hg (Sen 61.7%, Spe 88.9%), ILSBPD ≥ 13 mm Hg (Sen 50.6%, Spe 80.6%) and ABI ≤ 0.9 (Sen 53.3%, Spe 87.2%), showed significant correlation with AAD (all p < 0.001). Conclusions: Compared with healthy people, IASBPD and ILSBPD levels were higher and ABI levels were lower in patients with AAD. IASBPD ≥ 10 mm Hg and ILSBPD ≥ 13 mm Hg can be used as indicators for early screening of AAD, and IASBPD ≥ 10 mm Hg has better predictive value for the occurrence of AAD. In patients with typical chest pain, attention needs to be paid to measuring blood pressure in the extremities.

Are frog calls relatively difficult to locate by mammalian predators?

Frogs call in acoustically dense choruses to attract conspecific females. Their calls can potentially reveal their location to predators, many of which are mammals. However, frogs and mammals have very different acoustic receivers and mechanisms for determining sound source direction. We argue that frog calls may have been selected so that they are harder to locate with the direction-finding mechanisms of mammals. We focus on interaural time delay (ITD) estimation using delay-line coincidence detection (place code), and a binaural excitatory/inhibitory (E/I) ITD mechanism found in mammals with small heads (population code). We identify four "strategies" which frogs may employ to exploit the weaknesses of either mechanism. The first two strategies used by the frog confound delay estimation to increase direction ambiguity using highly periodic calls or narrowband calls. The third strategy relies on using short pulses. The E/I mechanism is susceptible to noise with sounds being pulled to the medial plane when signal-to-noise ratio is low. Together, these three strategies compromise both ongoing and onset determination of location using either mechanism. Finally, frogs call in dense choruses using various means for controlling synchrony, maintaining chorus tenure, and abruptly switching off calling, all of which serve to confound location finding. Of these strategies, only chorusing adversely impacts the localization performance of frogs' acoustic receivers. We illustrate these strategies with an analysis of calls from three different frog species.

Neuroethology of sound localization in anurans.

Albert Feng pioneered the study of neuroethology of sound localization in anurans by combining behavioral experiments on phonotaxis with detailed investigations of neural processing of sound direction from the periphery to the central nervous system. The main advantage of these studies is that many species of female frogs readily perform phonotaxis towards loudspeakers emitting the species-specific advertisement call. Behavioral studies using synthetic calls can identify which parameters are important for phonotaxis and also quantify localization accuracy. Feng was the first to investigate binaural processing using single-unit recordings in the first two auditory nuclei in the central auditory pathway and later investigated the directional properties of auditory nerve fibers with free-field stimulation. These studies showed not only that the frog ear is inherently directional by virtue of acoustical coupling or crosstalk between the two eardrums, but also confirmed that there are extratympanic pathways that affect directionality in the low-frequency region of the frog's hearing range. Feng's recordings in the midbrain also showed that directional information is enhanced by cross-midline inhibition. An important contribution toward the end of his career involved his participation in neuroethological research with a team of scientists working with frogs that produce ultrasonic calls.

Approach to glaucoma diagnosis and prediction based on multiparameter neural network.

PURPOSE: To investigate the effect of comprehensive factor analysis on the relationship between glaucoma assessment and combined parameters including trans-laminar cribrosa pressure difference (TLCPD) and fractional pressure reserve (FPR). METHODS: The clinical data of 1029 patients with 15 indicators from the medical records of Beijing Tongren Hospital and 600 cases with 1322 indicators from Beijing Eye Research were collected. The doc2vec method was used to vectorize. The multivariate imputation by chained equations (MICE) method was used to interpolate. The original data combined with TLCPD, combined with FPR, and not combined parameters were respectively applied to train the neural network based on VGG16 and autoencoder to predict glaucoma and to evaluate the effect of combined parameters. RESULTS: The accuracy rates used to classify the glaucoma of the two sets reach over 0.90, and the precision rates reach 0.70 and 0.80 respectively. After using TLCPD and FPR for the autoencoder method, the accuracy rates are both close to 1.0, and the precision rates are 0.90 and 0.70 respectively. CONCLUSION: Using the combined parameters of FPR and TLCPD can effectively improve the diagnosis and prediction of glaucoma. Compared with TLCPD, FPR is more suitable for improving the effect of neural network for glaucoma classification.

[Experimental Study on Effects of Mitral Regurgitation on Hydrodynamic Performance of Aortic Valve].

OBJECTIVE: Aims researches on the interaction between heart valves is limited in clinical. Meanwhile the data of in vitro testing are insufficient. In this study, the in vitro hydrodynamic performance of an aortic valve was studied by using a model of mitral regurgitation that could finely adjust the regurgitant volume. METHODS: The regurgitation of mitral valve was gradually increased under the certain condition of heart rate, stroke volume, and mean aortic pressure and captured the hydrodynamic performance of the aortic valve. RESULTS: The study on the hydrodynamic performance of mechanical aortic valve (25AJ-501) by using a model of mitral regurgitation found that the effective orifice area and mean pressure difference of the aortic valve are negatively correlated with the degree of mitral regurgitation. CONCLUSIONS: The method based on a model of mitral regurgitation that could finely adjust the regurgitant volume established in this study can be used to study the effect of mitral valve regurgitation on the hydrodynamic performance of the aortic valve.

Morphometric and Hemodynamic Analysis of the Compressed Iliac Vein.

PURPOSE: To investigate the relationship between the morphological structure and hemodynamic properties of the compressed iliac vein and explore the reason for the formation of thrombosis in the compressed iliac vein. MATERIALS AND METHODS: A total of 11 patients with iliac vein compression syndrome (IVCS) were included in this study, and their iliac veins were reconstructed in 3 dimensions (3D). The morphological structures of the iliac veins (confluence angle, degree of stenosis) were analyzed based on the 3D model. Variations in the hemodynamic properties of the iliac vein were investigated at 4 typical moments in one cardiac cycle, and the relationship between the different morphological configurations and the pressure difference was investigated. RESULTS: In the region of the compressed iliac vein, the blood flow velocity is accelerated and the pressure changes abruptly accompanied by the increase in pressure difference. Higher time averaged wall shear stress (TAWSS) and lower relative residence time (RRT) appeared in stenosis regions of compressed iliac vein, while TAWSS was low and RRT was large near the stenosis position. There was a strong positive correlation between the degree of stenosis and the pressure difference (r=0.894), and a positive correlation between the confluence angle of the iliac vein and the pressure difference (r=0.638). CONCLUSION: The morphological structure of the compressed iliac vein has an obvious influence on the hemodynamic surroundings; the pressure difference becomes larger when the degree of stenosis and the confluence angle increase. The iliac vein luminal areas with low TAWSS and high RRT near the compressed location can impede blood flow and lead to accumulation of blood components, which may increase the risk of thrombosis formation and should be fully considered in the treatment of IVCS.

Early diastolic mitral regurgitation in left ventricular aneurysm.

Diastolic mitral regurgitation is a type of functional mitral regurgitation that develops via a reversal of the left atrioventricular pressure gradient during diastole. This study aimed to explore the mechanism underlying early diastolic mitral regurgitation (EDMR) in patients with left ventricular (LV) aneurysms after anterior myocardial infarction (AMI) by assessing the intraventricular pressure difference using vector flow mapping. We enrolled 23 consecutive patients with LV aneurysms (with and without EDMR) and 15 healthy men as controls. In the control group, LV suction began from the apex during early diastole. In contrast, the blood that pooled in the apical aneurysm during systole generated a relatively higher pressure at the apex than at the basal LV during early diastole; consequently, the pressure reversal phenomenon occurred in the LV. Compared to the EDMR- group, the EDMR + group (n = 7) exhibited a significantly higher diastolic time ratio ([time from the second heart sound to the pressure inversion point]/[total diastolic time]) (P < 0.001). The diastolic time ratio was significantly correlated with log BNP, but not with E/A, E/E', or the left atrial expansion index. In conclusion, EDMR in LV aneurysm may be due to a prolonged diastolic time ratio leading to prolonged pressure inversion in the LV during early diastole.

Characteristics of four-limb blood pressure and brachial-ankle pulse wave velocity in Chinese patients with Takayasu arteritis.

Purpose: Takayasu arteritis (TA) is a rare disease, which is frequently misdiagnosed or its diagnosis can be missed. This study aimed to analyse the characteristics of four-limb blood pressure (4LBP) and brachial-ankle pulse wave velocity (baPWV) in patients with TA, which could be useful in disease detection.Materials and Methods: We consecutively enrolled 182 patients with TA at Fuwai Hospital between January 2013 and January 2016. Pulse pressure (PP), pulsatile index (PI), inter-arm systolic blood pressure (SBP) difference (IASBPD), inter-leg SBP difference (ILSBPD), ankle-brachial index (ABI), baPWV, and inter-side baPWV difference (ΔbaPWV) were analysed and compared with those of age-, sex-, and SBP-matched participants without cardiovascular diseases.Results: In the TA group, the diastolic blood pressure was lower (67.4 ± 23.7 vs 84.1 ± 15.0 mmHg), PP was larger (69.7 ± 23.6 vs 53.7 ± 10.6 mmHg), PI was higher (1.3 ± 2.1 vs. 0.6 ± 0.1 mmHg), IASBPD was larger (18.2 ± 24.1 vs 4.2 ± 3.3 mmHg), and ILSBPD was larger (10.7 ± 15.0 vs 5.3 ± 4.1 mmHg) than those of the controls (all p < 0.01). Moreover, the proportions of PP >70 mmHg (36.8% vs 4.4%), PI > 1.0 (40.1% vs 2.2%), IASBPD >15 mmHg (34.6% vs. 0%), highest ABI >1.4 (17.6% vs. 0%), ILSBPD >15 mmHg (14.8% vs. 3.3%), lowest ABI < 0.9 (24.7% vs 2.2%), and ΔbaPWV > 185 cm/s (28.6% vs. 1.1%) were significantly greater in the TA group than in the control group (all p < 0.01). Approximately 80.8% of patients with TA (vs. 10.4% of controls) presented with at least one of these seven parameters (p = 0.000).Conclusion: The characteristics of 4LBP and baPWV in most patients with TA were abnormal, which helped us perform non-invasive primary screening and comprehensive evaluation of vascular lesions in such patients.

In daily life, many people measure the blood pressure of the arm but measuring the blood pressure of a single arm is inadequate because some hypertension and vascular diseases cannot be detected this way. Synchronous limb blood pressure measurements may be used to close this gap. Measuring synchronous limb blood pressure is very convenient and helps patients understand the value of limb blood pressure and examine many other useful parameters, such as the blood pressure differences between the two arms and two legs, as well as the ankle arm index. These values and derived parameters can also help detect many vascular diseases.Takayasu arteritis is a rare disease in young women. However, the aorta and branches of these patients are narrow or occluded. Patients often experience vague and ambiguous symptoms, such as hypertension or dizziness, so they are likely to be overlooked or misdiagnosed.Our study summarises the results of synchronous limb blood pressure measurements in patients with Takayasu arteritis and compares their results with those of a control population. Synchronous limb blood pressure measurements are easy and convenient and can detect vascular problems, which may improve the ability to diagnose Takayasu arteritis.

Inter-arm blood pressure difference is associated with contrast-induced nephropathy in patients with ST-segment elevation myocardial infarction who underwent primary percutaneous coronary intervention.

OBJECTIVE: Contrast-induced nephropathy (CIN) is a serious complication in patients with ST segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (p-PCI). An interarm systolic blood pressure difference (IASBD) ≥10 mmHg has been identified as an independent risk factor for cardiovascular disease and mortality. The aim of this study was to evaluate the predictive value of the IASBD for the risk of CIN in patients with STEMI who underwent p-PCI. METHOD: We prospectively investigated 2120 consecutive patients who were hospitalized with a diagnosis of STEMI and underwent p-PCI. A relative increase in serum creatinine levels of ≥ 25% or an absolute increase of ≥ 0.5 mg/dL from baseline within 72 h of contrast exposure was defined as CIN. The IASBD was calculated on admission to the emergency department. The risk of CIN was evaluated. RESULTS: The incidence of CIN was 6.6% (n = 139). The patients were divided into 2 groups based on the development of CIN. Age (p = .001), baseline creatinine levels (p < .001), DM (p < .001), HT (p < .001) and anemia (p = .001) were higher in patients with CIN. An IASBD ≥10 mmHg was noted in 13 (9.3%) patients in the CIN group and 83 (4.1%) (p = .001) in the non-CIN group (Table 1). According to the multivariate analysis, the IASBD was found to be a predictor of CIN development (OR: 2.36, 95% CI: 1.42-3.90, p: 0.001). CONCLUSION: The IASBD on admission can be a potential predictor of CIN development in patients with STEMI who underwent p-PCI.

[Interarm blood pressure difference: Concordance between two methods of automatic simultaneous measurement and between visits reproducibility]. / Diferencia de presión arterial entre brazos: concordancia entre 2 métodos automáticos de medición simultánea y reproducibilidad entre visitas.

OBJECTIVE: An increased interarm blood pressure difference (IAD) (≥10mmHg) has been associated with increased cardiovascular morbidity and mortality. There are few studies determining how IAD has to be measured and its reliability between visits. The objectives of our study were twofold. First, to evaluate the concordance between two automatic oscillometric devices for IAD measurement (two OMRON devices and one Microlife WatchBP™ device (WBP™)) and to analyse the reproducibility of IAD between visits in the general population attending a primary care centre. DESIGN: Descriptive cross-sectional study of concordance between the two methods and reproducibility of IAD between two visits separated by one week. SITE: Parets del Vallès primary care centre (Barcelona). PARTICIPANTS: General population aged 35-74 years. INTERVENTIONS AND MAIN MEASUREMENTS: One hundred and forty-nine patients completed the two visits. At each visit, IAD was measured three times with both methods and the mean of the three determinations was considered. Other variables such as sociodemographic and anthropometric variables, pathological antecedents and pharmacological treatment were collected through a review of the medical history and an interview with the patient. Concordance between the two devices and between visits reproducibility were calculated using the Lin concordance coefficient (CCL) for IAD expressed continuously and kappa(k) indices for IAD categorised as normal or pathological. RESULTS: Concordance for IAD expressed continuously was low: CCL=0.13 (0.02-0.24). Concordance was also low for IAD categorised as normal or pathological (k=-0.03 (-0.05-0.00)). Reproducibility between visits was low for both methods and for both continuous and categorised IAD: with OMRON™ CCL=0.19 (0.03-0.34) and k=-0.02 (-0.16-0.12) and for WBP™ CCL=0.14 (-0.01-0.29) and k=0.49 (0.33-0.64). CONCLUSIONS: Concordance between two automatic oscillometers in the simultaneous IAD measurement was low. Reproducibility between visits was also low for both methods.

[Experimental study on the relationship between foam pressure difference and foam stability].

Foam stability affects the efficacy and incidence of side effects of foam sclerotherapy. Exploring the relationship between foam pressure difference and foam stability can provide ideas and basis for obtaining more stable foam. In the experiment, sodium cod liver oleate foam was selected, and poloxamer 188 (concentration of 0%, 4%, 8%, 12%) was added to realize the change of foam pressure. By using the self-written program to process the foam pictures, the foam pressure difference and the relationship between the foam stability indicators (water separation rate curve, half-life) and the foam pressure difference were obtained. The results showed that at first the foam pressure increased with the increase of the concentration, and then it decreased with the increase of the concentration and reached a peak at the concentration of 4%. The foam pressure difference decreases continuously with the increase of decay time. When the additive concentration is low, the foam average pressure difference increases. And if the additive concentration is too high, the foam average pressure difference decreases. The smaller the foam pressure difference is, the better the foam stability is. This paper lays a foundation for the research on the stability of foam hardener.

Novel coronavirus SARS-CoV-2 (Covid-19) dynamics inside the human body.

A knowledge-based cybernetic framework model representing the dynamics of SARS-CoV-2 inside the human body has been studied analytically and in silico to explore the pathophysiologic regulations. The following modeling methodology was developed as a platform to introduce a predictive tool supporting a therapeutic approach to Covid-19 disease. A time-dependent nonlinear system of ordinary differential equations model was constructed involving type-I cells, type-II cells, SARS-CoV-2 virus, inflammatory mediators, interleukins along with host pulmonary gas exchange rate, thermostat control, and mean pressure difference. This formalism introduced about 17 unknown parameters. Estimating these unknown parameters requires a mathematical association with the in vivo sparse data and the dynamic sensitivities of the model. The cybernetic model can simulate a dynamic response to the reduced pulmonary alveolar gas exchange rate, thermostat control, and mean pressure difference under a very critical condition based on equilibrium (steady state) values of the inflammatory mediators and system parameters. In silico analysis of the current cybernetical approach with system dynamical modeling can provide an intellectual framework to help experimentalists identify more active therapeutic approaches.

Prediction of internal carotid artery aneurysm recurrence by pressure difference at the coil mass surface.

PURPOSE: A previous study on computational fluid dynamics reported that a high pressure difference (PD) at the surface of a coil mass is a strong predictor of aneurysm recurrence after coil embolization. PD was calculated using a virtual post-coiling model (VM), created by manually cutting the aneurysm by the flat plane from an anatomic model created with pre-coil embolization data; however, its credibility has not been fully evaluated. This study aims to clarify whether PD values calculated using the post-coiling model, which reflects the actual coil plane, are a strong predictor of aneurysm recurrence. METHODS: Fifty internal carotid artery aneurysms treated with endovascular coil embolization were analyzed (7 recanalized, 43 stable). We created and subjected two post-coiling models, namely, VM and the real post-coiling model (RM), constructed from the post-coil embolization data. The relationship between PD and aneurysm recurrence was examined using these models. PD and its constituent three parameters were compared between VM and RM. RESULTS: PD values calculated using RM showed significantly higher aneurysm recurrence in recurrence group than stable group (p < 0.001), and multivariate analysis showed that PD in RM (p = 0.02; odds ratio, 36.24) was significantly associated with aneurysm recurrence. The receiver operating characteristic analysis revealed that PD values accurately predicted aneurysm recurrence (area under the curve, 0.977; cutoff value, 3.08; sensitivity, 100%; specificity, 97.7%). All four parameters showed a significant correlation with VM and RM (p < 0.001). CONCLUSION: Use of PD to predict recurrence after coil embolization can be clinically relevant.

Noninvasive assessment of intraventricular pressure difference in left ventricular dyssynchrony using vector flow mapping.

Diastolic intraventricular pressure difference (IVPD) reflects left ventricular (LV) diastolic function. The relative pressure imaging (RPI) enables the noninvasive quantification of IVPD based on vector flow mapping (VFM) and visualization of regional pressure distribution. LV dyssynchrony causes deterioration of cardiac performance. However, it remains unclear how IVPD is modulated by LV dyssynchrony. LV dyssynchrony was created in ten open-chest dogs by right ventricular (RV) pacing. The other ten dogs undergoing right atrial (RA) pacing set at the similar heart rate with RV pacing were used as controls. Echocardiographic images were acquired at baseline and during pacing simultaneously with LV pressure measurement by a micromanometer. Pressure difference (ΔP) was computed between the apex and the base of the LV inflow tract during a cardiac cycle by RPI and ΔP during isovolumic relaxation time (ΔPIRT), a parameter of diastolic suction, and that during early filling phase (ΔPE) were measured. During RV pacing, stroke volume (SV) and ΔPIRT decreased significantly, while ΔPE did not change compared to the baseline. During RA pacing, SV, ΔPIRT and ΔPE did not change significantly. ΔPIRT tended to correlate with -dP/dtmin and end-systolic volume, and significantly correlated with ejection fraction. IVPD during isovolumic relaxation time was decreased by LV dyssynchrony, while IVPD during early filling phase was not. A reduction of diastolic suction is observed in LV dyssynchrony and is significantly related to a decrease in SV.

Assessment of Extensive Airway Obstruction Using Point-by-Point Lateral Pressure Measurements during Bronchoscopy.

BACKGROUND: The positioning of the stent at the flow-limiting segment is crucial for patients with extensive airway obstruction to relieve dyspnea. However, CT and flow-volume curves cannot detect the area of maximal obstruction. OBJECTIVES: The aim of this study is to physiologically evaluate extensive airway obstruction during interventional bronchoscopy. METHODS: We prospectively measured point-by-point lateral airway pressure (Plat) at multiple points from the lower lobe bronchus to the upper trachea using a double-lumen catheter in 5 patients. The site of maximal obstruction was evaluated continuously to measure point-by-point Plat at multiple points when the airway catheter was withdrawn from the lower lobe bronchus to the upper trachea. RESULTS: Remarkable pressure differences occurred at the site of maximal obstruction assessed by point-by-point Plat measurements. After initial stenting in 1 case, migration of the maximal obstruction to a nonstented segment of the weakened airway was seen with extensive stenosis from the trachea to the bronchi. In the second case, in addition to radiological analysis, point-by-point Plat measurements could identify the location of the maximal obstruction which contributed to dyspnea. CONCLUSIONS: Point-by-point Plat measurement could be used to detect the site of maximal obstruction physiologically. Furthermore, Plat measurement could assess the need for additional procedures in real time in patients with extensive airway obstruction.