Validation of oscillometric ratio and maximum gradient methods for non-invasive blood pressure measurement with intra-arterial blood pressure measurements as reference.

Most non-invasive blood pressure (BP) measurements are carried out using instruments which implement either the Ratio or the Maximum Gradient oscillometric method, mostly during cuff deflation, but more rarely during cuff inflation. Yet, there is little published literature on the relative advantages and accuracy of these two methods. In this study of 40 lightly sedated individuals aged 64.1 ± 9.6 years, we evaluate and compare the performance of the oscillometric ratio (K) and gradient (Grad) methods for the non-invasive estimation of mean pressure, SBP and DBP with reference to invasive intra-arterial values. There was no significant difference between intra-arterial estimates of mean pressure made via Korotkoff sounds (MP-OWE) or the gradient method (MP-Grad). However, 17.7% of MP-OWE and 15% of MP-Grad were in error by more than 10 mmHg. SBP-K and SBP-Grad underestimated SBP by 14 and 18 mmHg, whilst accurately estimating DBP with mean errors of 0.4 ±â€Š5.0 and 1.7 ±â€Š6.1 mmHg, respectively. Relative to the reference standard SBP-K, SBP-Grad and DBP-Grad were estimated with a mean error of -4.5 ±â€Š6.6 and 1.4 ±â€Š5.6 mmHg, respectively, noting that using the full range of recommended ratios introduces errors of 12 and 7 mmHg in SBP and DBP, respectively. We also show that it is possible to find ratios which minimize the root mean square error (RMSE) and the mean error for any particular individual cohort. We developed linear models for estimating SBP and SBP-K from a range of demographic and non-invasive OWE variables with resulting mean errors of 0.15 ±â€Š5.6 and 0.3 ±â€Š5.7 mmHg, acceptable according to the Universal standard.

A Continuous Non-Invasive Blood Pressure Prediction Method Based on Deep Sparse Residual U-Net Combined with Improved Squeeze and Excitation Skip Connections.

Arterial blood pressure (ABP) serves as a pivotal clinical metric in cardiovascular health assessments, with the precise forecasting of continuous blood pressure assuming a critical role in both preventing and treating cardiovascular diseases. This study proposes a novel continuous non-invasive blood pressure prediction model, DSRUnet, based on deep sparse residual U-net combined with improved SE skip connections, which aim to enhance the accuracy of using photoplethysmography (PPG) signals for continuous blood pressure prediction. The model first introduces a sparse residual connection approach for path contraction and expansion, facilitating richer information fusion and feature expansion to better capture subtle variations in the original PPG signals, thereby enhancing the network's representational capacity and predictive performance and mitigating potential degradation in the network performance. Furthermore, an enhanced SE-GRU module was embedded in the skip connections to model and weight global information using an attention mechanism, capturing the temporal features of the PPG pulse signals through GRU layers to improve the quality of the transferred feature information and reduce redundant feature learning. Finally, a deep supervision mechanism was incorporated into the decoder module to guide the lower-level network to learn effective feature representations, alleviating the problem of gradient vanishing and facilitating effective training of the network. The proposed DSRUnet model was trained and tested on the publicly available UCI-BP dataset, with the average absolute errors for predicting systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean blood pressure (MBP) being 3.36 ± 6.61 mmHg, 2.35 ± 4.54 mmHg, and 2.21 ± 4.36 mmHg, respectively, meeting the standards set by the Association for the Advancement of Medical Instrumentation (AAMI), and achieving Grade A according to the British Hypertension Society (BHS) Standard for SBP and DBP predictions. Through ablation experiments and comparisons with other state-of-the-art methods, the effectiveness of DSRUnet in blood pressure prediction tasks, particularly for SBP, which generally yields poor prediction results, was significantly higher. The experimental results demonstrate that the DSRUnet model can accurately utilize PPG signals for real-time continuous blood pressure prediction and obtain high-quality and high-precision blood pressure prediction waveforms. Due to its non-invasiveness, continuity, and clinical relevance, the model may have significant implications for clinical applications in hospitals and research on wearable devices in daily life.

Assessment and management of exaggerated blood pressure response to standing and orthostatic hypertension: consensus statement by the European Society of Hypertension Working Group on Blood Pressure Monitoring and Cardiovascular Variability.

Recent evidence suggests that an exaggerated blood pressure (BP) response to standing (ERTS) is associated with an increased risk of adverse outcomes, both in young and old individuals. In addition, ERTS has been shown to be an independent predictor of masked hypertension. In the vast majority of studies reporting on the prognostic value of orthostatic hypertension (OHT), the definition was based only on systolic office BP measurements. This consensus statement provides recommendations on the assessment and management of individuals with ERTS and/or OHT. ERTS is defined as an orthostatic increase in SBP at least 20 mmHg and OHT as an ERTS with standing SBP at least 140 mmHg. This statement recommends a standardized methodology to assess ERTS, by considering body and arm position, and the number and timing of BP measurements. ERTS/OHT should be confirmed in a second visit, to account for its limited reproducibility. The second assessment should evaluate BP changes from the supine to the standing posture. Ambulatory BP monitoring is recommended in most individuals with ERTS/OHT, especially if they have high-normal seated office BP. Implementation of lifestyle changes and close follow-up are recommended in individuals with ERTS/OHT and normotensive seated office BP. Whether antihypertensive treatment should be administered in the latter is unknown. Hypertensive patients with ERTS/OHT should be managed as any other hypertensive patient. Standardized standing BP measurement should be implemented in future epidemiological and interventional studies.

Hypertension Trends and Disparities Over 12 Years in a Large Health System: Leveraging the Electronic Health Records.

BACKGROUND: The digital transformation of medical data enables health systems to leverage real-world data from electronic health records to gain actionable insights for improving hypertension care. METHODS AND RESULTS: We performed a serial cross-sectional analysis of outpatients of a large regional health system from 2010 to 2021. Hypertension was defined by systolic blood pressure ≥140 mm Hg, diastolic blood pressure ≥90 mm Hg, or recorded treatment with antihypertension medications. We evaluated 4 methods of using blood pressure measurements in the electronic health record to define hypertension. The primary outcomes were age-adjusted prevalence rates and age-adjusted control rates. Hypertension prevalence varied depending on the definition used, ranging from 36.5% to 50.9% initially and increasing over time by ≈5%, regardless of the definition used. Control rates ranged from 61.2% to 71.3% initially, increased during 2018 to 2019, and decreased during 2020 to 2021. The proportion of patients with a hypertension diagnosis ranged from 45.5% to 60.2% initially and improved during the study period. Non-Hispanic Black patients represented 25% of our regional population and consistently had higher prevalence rates, higher mean systolic and diastolic blood pressure, and lower control rates compared with other racial and ethnic groups. CONCLUSIONS: In a large regional health system, we leveraged the electronic health record to provide real-world insights. The findings largely reflected national trends but showed distinctive regional demographics and findings, with prevalence increasing, one-quarter of the patients not controlled, and marked disparities. This approach could be emulated by regional health systems seeking to improve hypertension care.

One size does not fit all: universal cuff overestimates oscillometric blood pressure in persons with large arm circumference.

OBJECTIVE: Some brachial cuffs for oscillometric blood pressure (BP) measurement are claimed to cover a wide range of upper-arm circumferences; however, their validation is rarely conducted. Our aim was to compare oscillometric BP measurements obtained with a universal cuff with those obtained with an appropriately sized cuff. METHODS: We utilised the Microlife B6 Connect monitor, conducting oscillometric BP measurements in a random sequence with both a universal cuff (recommended for arm circumferences from 22 to 42 cm) and an appropriately sized cuff (medium for circumference 22-32 cm and large for 32-42 cm). We included 91 individuals with an arm circumference of 22-32 cm and 64 individuals with an arm circumference of 32-42 cm. RESULTS: For arm circumferences > 32 cm, systolic and diastolic BP measured with the universal cuff was higher than that measured with the large cuff (systolic 6.4 mmHg, 95% confidence interval [CI]). 3.9-8.8, diastolic 2.4 mmHg, 95%CI, 1.2-3.7, p < 0.001 for both). Overestimation of BP with the universal cuff was statistically significant after correcting for the sequence of measurements. No statistical difference was found between the universal cuff and medium cuff for circumferences in the 22-32 cm range. The bladder size in the universal cuff matched the dimensions of the medium-sized cuff; however, the cuff was larger. CONCLUSION: Overestimation of BP measured with a universal cuff in persons with large arm circumferences is clinically important. It poses the risk of unnecessary initiation or intensification of antihypertensive medication in persons using the universal cuff.

What is the context?Clinical guidelines recommend individualisation of the size of the cuff used for blood pressure measurement according to the circumference of the upper arm.Many blood pressure monitors are sold with a single "universal" cuff claimed to cover a wide range of upper arm sizes.We compared blood pressure obtained with the Microlife B6 Connect monitor and a "universal" cuff with the results obtained with individual sized cuffs (medium size for arm circumference between 22 and 32 cm and large size for arm circumference between 32 and 42 cm).What is new?In persons with large upper arm circumference is the systolic blood pressure 6.4 mmHg higher and the diastolic blood pressure 2.4 mmHg higher with the universal cuff than with the individual-sized large cuff.What is the impact?The universal cuff overestimates blood pressure in persons with large arm circumference.

Mechanistic Assessment of Cardiovascular State Informed by Vibroacoustic Sensors.

Monitoring blood pressure, a parameter closely related to cardiovascular activity, can help predict imminent cardiovascular events. In this paper, a novel method is proposed to customize an existing mechanistic model of the cardiovascular system through feature extraction from cardiopulmonary acoustic signals to estimate blood pressure using artificial intelligence. As various factors, such as drug consumption, can alter the biomechanical properties of the cardiovascular system, the proposed method seeks to personalize the mechanistic model using information extracted from vibroacoustic sensors. Simulation results for the proposed approach are evaluated by calculating the error in blood pressure estimates compared to ground truth arterial line measurements, with the results showing promise for this method.

Impact of sleep quality and physical activity on blood pressure variability.

Increased blood pressure variability (BPV) is linked to cardiovascular disease and mortality, yet few modifiable BPV risk factors are known. We aimed to assess the relationship between sleep quality and activity level on longitudinal BPV in a cohort of community-dwelling adults (age ≥18) from 17 countries. Using Withings home measurement devices, we examined sleep quality and physical activity over one year, operationalized as mean daily step count and number of sleep interruptions, both transformed into tertiles. The primary study outcome was high BPV, defined as the top tertile of systolic blood pressure standard deviation. Our cohort comprised 29,375 individuals (mean age = 58.6 years) with 127.8±90.1 mean days of measurements. After adjusting for age, gender, country, body mass index, measurement days, mean blood pressure, and total time in bed, the odds ratio of having high BPV for those in the top tertile of sleep interruptions (poor sleep) was 1.37 (95% CI, 1.28-1.47) and 1.44 (95% CI, 1.35-1.54) for those in the lowest tertile of step count (physically inactive). Combining these exposures revealed a significant excess relative risk of 0.20 (95% CI, 0.04-0.35, p = 0.012), confirming their super-additive effect. Comparing individuals with the worst exposure status (lowest step count and highest sleep interruptions, n = 2,690) to those with the most optimal status (highest step count and lowest sleep interruptions, n = 3,531) yielded an odds ratio of 2.01 (95% CI, 1.80-2.25) for high BPV. Our findings demonstrate that poor sleep quality and physical inactivity are associated with increased BPV both independently and super-additively.

Validation of a Suprasystolic Cuff System for Static and Dynamic Representation of the Central Pressure Waveform.

BACKGROUND: Noninvasive pulse waveform analysis is valuable for central cardiovascular assessment, yet controversies persist over its validity in peripheral measurements. Our objective was to compare waveform features from a cuff system with suprasystolic blood pressure hold with an invasive aortic measurement. METHODS AND RESULTS: This study analyzed data from 88 subjects undergoing concurrent aortic catheterization and brachial pulse waveform acquisition using a suprasystolic blood pressure cuff system. Oscillometric blood pressure (BP) was compared with invasive aortic systolic BP and diastolic BP. Association between cuff and catheter waveform features was performed on a set of 15 parameters inclusive of magnitudes, time intervals, pressure-time integrals, and slopes of the pulsations. The evaluation covered both static (subject-averaged values) and dynamic (breathing-induced fluctuations) behaviors. Peripheral BP values from the cuff device were higher than catheter values (systolic BP-residual, 6.5 mm Hg; diastolic BP-residual, 12.4 mm Hg). Physiological correction for pressure amplification in the arterial system improved systolic BP prediction (r2=0.83). Dynamic calibration generated noninvasive BP fluctuations that reflect those invasively measured (systolic BP Pearson R=0.73, P<0.001; diastolic BP Pearson R=0.53, P<0.001). Static and dynamic analyses revealed a set of parameters with strong associations between catheter and cuff (Pearson R>0.5, P<0.001), encompassing magnitudes, timings, and pressure-time integrals but not slope-based parameters. CONCLUSIONS: This study demonstrated that the device and methods for peripheral waveform measurements presented here can be used for noninvasive estimation of central BP and a subset of aortic waveform features. These results serve as a benchmark for central cardiovascular assessment using suprasystolic BP cuff-based devices and contribute to preserving system dynamics in noninvasive measurements.

Chronic kidney disease and orthostatic hypotension in hospitalised older adults.

PURPOSE: Orthostatic hypotension (OH) may predispose older adults to health complications leading to functional impairment. Despite the central role of the kidney in blood pressure control, the contribution of renal function in orthostatic hypotension is poorly investigated. To verify the association between Chronic Kidney Disease (CKD) and OH a population of hospitalised elderly patients with comorbidities was studied. MATERIALS AND METHODS: 174 patients were consecutively admitted to Acute Geriatric Wards. On admission, patients underwent postural systolic (SBP) and diastolic (DBP) blood pressure evaluation by automatic oscillometric device after 10 min rest in lying position, and in standing position at time 0, 1, 3 and 5 min. CKD was assumed for estimated glomerular filtration rate (e-GFR) less than 60 mL/min/1.73 m2. RESULTS: The mean age of the population enrolled was 74.4 ± 7.0. OH was found in 46.0% and CKD in 56.3% of patients, respectively. A lower e-GFR was observed in patients with (56.1 ± 16.7 mL/min/1.73 m2) than in those without OH (61.1 ± 15.9 mL/min/1.73 m2) (p < 0.05). A greater fall in SBP at 0-min (12.8 ± 6.3 vs. 7.7 ± 3.2 mmHg) and at 1-min (8.4 ± 4.5 vs. 5.7 ± 2.8 mmHg) was found in CKD patients in respect to patients without CKD during active standing test (p < 0.05). Similarly, a DBP reduction at 0-min and at 1-min was observed in CKD patients in respect to patients without CKD (p < 0.05). A multivariate logistic regression analysis showed that CKD was associated to OH (OR 2.426; 95%CI 1.192-4.937; p = 0.014). CONCLUSIONS: CKD is associated to OH in hospitalised older adults.

Frequency of office blood pressure measurements and the seasonal variability of blood pressure: results of the Hungarian Hypertension Registry.

PURPOSE: Hypertension is a major public health problem, thus, its timely and appropriate diagnosis and management are crucial for reducing cardiovascular morbidity and mortality. The aim of the new Hungarian Hypertension Registry is to evaluate the blood pressure measurement practices of general practitioners (GPs), internists and cardiologists in outpatient clinics, as well as to assess the seasonal variability of blood pressure. MATERIALS AND METHODS: Omron M3 IT devices were used during four-month periods between October 2018 and April 2023 in GP practices and in hypertension clinics. The blood pressure data were then transmitted online from the monitors' cuffs to a central database using the Medistance system of Omron. RESULTS: Family physicians (n = 2491), and internists/cardiologists (n = 477) participated in the study. A total of 4804 821 blood pressure measurements were taken during 10 four-month evaluation periods. In the ten periods, the daily average number of measurements was between 3.0 and 5.6. Following ESH diagnostic criteria, the proportion of subjects in optimal, normal and high-normal blood pressure categories were 14, 13.4 and 16.7%, respectively. Altogether 56% of the measurements belonged to stage 1, stage 2 or stage 3 hypertension categories (31.6, 17.1 and 7.4%, respectively). On average, a difference of 5/2 mmHg was observed between winter and summer data in systolic and diastolic blood pressures, respectively. The average systolic blood pressure values were higher in GP practices with more than 2000 patients than in the ones with less than 1500 patients (141.86 mmHg versus 140.02 mmHg, p < 0.05). CONCLUSION: In conclusion, the low daily average number of blood pressure measurements indicates a limited blood pressure screening awareness/capacity in the case of Hungarian family physicians. In GP practices with more patients, blood pressure is usually less well-controlled. These results suggest that the further promotion of home blood pressure monitoring is necessary.

What is the background?The standard method for the diagnosis of hypertension and for the control of treatment efficacy in hypertensive patients is office blood pressure measurement.Until now we had no real-life data on the blood pressure measurement practices of general practitioners (GPs), internists and cardiologists.Although seasonal differences in blood pressure values are well known, we had no data on the extent of these changes.What is new?In this real-world, nationwide observational study we were able to measure the frequency of blood pressure measurements in the daily practice of GPs, internists and cardiologists in Hungary, which was found to be very low compared to the number of patients they treat. In practices with more patients, blood pressure is generally less well-controlled.We could also detect a significant seasonal variation in systolic and diastolic blood pressure values over the observed time periods.What is the impact?The low daily average number of blood pressure measurements indicates a limited blood pressure screening awareness/capacity in the case of Hungarian family physicians, supporting the further promotion of home blood pressure measurement.The marked seasonal blood pressure changes demonstrated by our study require attention and the individual adjustment of treatment in different seasons.

Blood pressure and the hypertension care cascade in The Gambia: Findings from a nationwide survey.

Community treatment of hypertension in sub-Saharan Africa is hampered by gaps at several stages of the care cascade. We compared blood pressure (BP) levels (systolic, diastolic and pulse pressures) in four groups of participants by hypertension and treatment status. We conducted a nationally representative survey of adults 35 years and older using a multistage sampling strategy based on the 2013 Gambia Population and Housing Census. The BP measurements were taken in triplicate 5 min apart, and the average of the last two measurements was used for analysis. Systolic and diastolic BP levels and pulse pressure were compared by hypertension status using mean and 95% confidence intervals (CI). 53.1% of the sample were normotensive with mean systolic BP (SBP) of 119.2 mmHg (95% CI, 118.7-119.6) and diastolic BP (DBP) of 78.1 mmHg (77.8-78.3). Among individuals with hypertension, mean SBP was 148.7 mmHg (147.7-149.7) among those unaware of their hypertension, 152.2 mmHg (151.0-153.5) among treated individuals and was highest in untreated individuals at 159.3 mmHg (157.3-161.2). The findings were similar for DBP levels, being 93.9 mmHg (93.4-94.4) among the unaware, 95.1 mmHg (94.4-95.8) among the treated and highest at 99.1 mmHg (98.1-100.2) in untreated participants. SBP and DBP were higher in men, and SBP was as expected higher in those aged ≥55 years. BP level was similar in urban and rural areas. Our data shows high BP levels among participants with hypertension including those receiving treatment. Efforts to reduce the health burden of hypertension will require inputs at all levels of the care cascade.

Association of postexercise blood pressure with cardiovascular outcomes and mortality: The CARDIA study.

Postexercise blood pressure (BP) may be a better predictor of cardiovascular risk than office BP, but there is a lack of data supporting this claim. We hypothesized that postexercise BP may be an important prognostic marker. Our aim was to evaluate the association of postexercise BP with major adverse cardiovascular events (MACE) and all-cause mortality. A total of 2581 participants (median age, 46 years; 55.9% women) from the Coronary Artery Risk Development in Young Adults study at year 20 (2005-2006) who underwent a graded exercise treadmill test using a modified Balke graded protocol were included. Postexercise BP was measured at baseline. Cox models were used to estimate the associations of postexercise BP with MACE and all-cause mortality. Participants were followed up until December 31, 2021. In the entire population, postexercise systolic BP showed no significant association with MACE or all-cause mortality, while postexercise diastolic BP was associated with MACE (hazard ratios [HR], 1.27 [95% CI, 1.06-1.52], per 10 mmHg increase) and all-cause mortality (HR, 1.26 [95% CI, 1.05-1.51], per 10 mmHg increase). In the normal BP group, postexercise systolic BP was not significantly associated with MACE or all-cause mortality, and postexercise diastolic BP was strongly associated with MACE (HR, 1.57 [95% CI, 1.18-2.09], per 10 mmHg increase). In this population-based cohort study, postexercise diastolic BP was significantly associated with the risk of MACE and all-cause mortality. Among individuals with normal BP, postexercise diastolic BP could identify those at a higher risk of cardiovascular events.

Comparison of Doppler ultrasonic sphygmomanometry, oscillometry and high-definition oscillometry for non-invasive blood pressure measurement in conscious cats.

OBJECTIVES: Systemic arterial hypertension is a common occurrence and can have serious adverse consequences in cats. Therefore, measuring blood pressure is very important. There are many indirect blood pressure measurement devices available. This study compared Doppler, oscillometric (petMAP Graphic II, SunTech Vet20, the Cardell Insight-X0000) and high-definition oscillometry devices for the non-invasive measurement of blood pressure in conscious cats. METHODS: In this prospective study, blood pressure was measured in 32 cats using the different devices according to the recommendations of the American College of Veterinary Internal Medicine Consensus Statement. Blood pressures (systolic blood pressure [SBP], diastolic blood pressure [DBP], mean arterial pressure [MAP]), time to complete measurements, number of attempts needed, coefficient of variation (CV) between the blood pressure measurements of the different devices, ease of completing measurements and apparent stress level of the cat were assessed. RESULTS: There was a significant difference between devices in the time taken to obtain blood pressure readings and the number of attempts necessary to obtain six reliable measurements. The CV of the Doppler device was significantly smaller than that of the rest of the devices, but there were no other differences between the devices. The mean SBP, DBP and MAP measured by the petMAP device were significantly higher than the measurements from the other devices. The perceived ease of measurement was not significantly different between the various machines. The perceived level of stress of measurement with the Doppler device was significantly higher compared with the other devices but did not lead to an increased SBP. CONCLUSIONS AND RELEVANCE: Using a Doppler device to measure blood pressure in conscious cats is fast, relatively easy and gives reliable results. A disadvantage is that the Doppler device can only measure SBP, while oscillometric devices also provide DBP and MAP. However, in veterinary medicine, systolic hypertension is considered the most relevant.

Finger cuff versus invasive and noninvasive arterial pressure measurement in pregnant patients with obesity.

BACKGROUND: Pregnant patients with obesity may have compromised noninvasive blood pressure (NIBP) measurement. We assessed the accuracy and trending ability of the ClearSight™ finger cuff (FC) with invasive arterial monitoring (INV) and arm NIBP, in obese patients having cesarean delivery. METHODS: Participants were aged ≥18 years, ≥34 weeks gestation, and body mass index (BMI) ≥ 40 kg m-2. FC, INV, and NIBP measurements were obtained across 5-min intervals. The primary outcome was agreement of FC measurements with those of the reference standard INV, using modified Bland-Altman plots. Secondary outcomes included comparisons between FC and NIBP and NIBP versus INV, with four-quadrant plots performed to report discordance rates and evaluate trending ability. RESULTS: Twenty-three participants had a median (IQR) BMI of 45 kg m-2 (44-48). When comparing FC and INV the mean bias (SD, 95% limits of agreement) for systolic blood pressure (SBP) was 16 mmHg (17, -17.3 to 49.3 mmHg), for diastolic blood pressure (DBP) -0.2 mmHg (10.5, -20.7 to 20.3), and for mean arterial pressure (MAP) 5.2 mmHg (11.1, -16.6 to 27.0 mmHg). Discordance occurred in 54 (26%) pairs for SBP, 41 (23%) for DBP, and 41 (21.7%) for MAP. Error grid analysis showed 92.1% of SBP readings in Zone A (no-risk zone). When comparing NIBP and INV, the mean bias (95% limits of agreement) for SBP was 13.0 mmHg (16.7, -19.7 to 29.3), for DBP 5.9 mmHg (11.9, -17.4 to 42.0), and for MAP 8.2 mmHg (11.9, -15.2 to 31.6). Discordance occurred in SBP (84 of 209, 40.2%), DBP (74 of 187, 39.6%), and MAP (63 of 191, 33.0%). CONCLUSIONS: The FC and NIBP techniques were not adequately in agreement with INV. Trending capability was better for FC than NIBP. Clinically important differences may occur in the setting of the perfusion-dependent fetus.

Comparison of choroidal thickness and choroidal vascular index in normotensive dippers and nondippers.

OBJECTIVE: The aim of this study was to evaluate the choroidal thickness and choroidal vascular index in normotensive individuals with dipping and nondipping patterns. METHODS: Patients who applied to the cardiology clinic for routine checkups and underwent 24-h blood pressure monitoring were included in our study. They were divided into two groups based on their dipper status. The patients in whom systolic blood pressure decreased during the nocturnal time by 10% or more of the daily blood pressure were defined as dippers. On the contrary, patients whose nocturnal systolic blood pressure decreased by less than 10% were defined as nondippers. Choroidal thickness and choroidal vascular index were measured by spectral-domain optical coherence tomography. Central macular thickness, retinal nerve fiber layer, and ganglion cell layer (GCL) analyses were also recorded. RESULTS: In total, 35 patients with dipper pattern and 34 patients with nondipper pattern were recruited. The mean subfoveal choroidal thickness was 349.72±90 µm in the dipper group and 358.54±132.5 µm in the nondipper group. The groups had no significant difference in choroidal thickness, central macular thickness, retinal nerve fiber layer, and ganglion cell layer analyses. However, the choroidal vascular index was statistically significantly lower in the nondipper group when compared to the dipper group (0.61±0.02 vs. 0.64±0.02; p<0.001). Also, the choroidal vascular index was negatively correlated with subfoveal choroidal thickness in the nondipper group (Spearman; r=-0.419; p=0.033). CONCLUSION: Our study showed that the choroidal vascular index was significantly lower in nondippers than in dippers. Nondipper individuals may be affected by vascular dysregulation, leading to alterations in the choroidal circulation.

A New Approach to Vascular Screening: Identification of Impaired Vascular Function Using the FMSF Technique.

Arterial blood pressure monitoring plays an important role in preventive medicine, allowing, in selected cases, the identification of vascular dysfunction. In this review, we propose a new non-invasive approach to assessment of the circulatory system, based on its reaction to hypoxia induced by post-occlusive reactive hyperemia (PORH). Three key parameters can be used for vascular screening: the Reactive Hyperemia Response (RHR), which represents the overall reaction of the macro- and microcirculation to transient hypoxia; Hypoxia Sensitivity (HS), which reflects hypoxia-induced activation of myogenic oscillations of the microcirculation; and Normoxia Oscillatory Index (NOI), which characterizes microcirculatory oscillations under normoxia conditions. A method for assessing these parameters, analogous in simplicity to arterial blood pressure measurement, is provided by the Flow Mediated Skin Fluorescence (FMSF) technique. Reference values are proposed based on numerous test measurements.