Comparison of Doppler ultrasonic and oscillometric devices (with or without 2 proprietary optimizations) for non-invasive blood pressure measurement in conscious 3 cats

Objectives This study compared Doppler and oscillometric (PetMAP+) devices (with or without proprietary optimisations) for the non-invasive measurement of blood pressure in conscious cats. Methods Twenty-three cats were enrolled; however, five were excluded as fewer than five measurements were obtained for each assessment. All measurements were obtained according to American College of Veterinary Internal Medicine consensus guidelines. Oscillometric device modes A and B were operated according to the manufacturer’s guidelines. Doppler and oscillometric devices were used alternately as the first device. Results Systolic arterial blood pressure (SAP) measurements were obtained by Doppler (SAPd) and oscillometry; the mean of each set of five values was used for statistical analysis. There was a significant difference between SAPd and SAP measurements in oscillometric modes A (P <0.001) and B (P <0.001). While both modes measured SAP higher than SAPd, B had a smaller bias (+15.72 mmHg) and narrower limits of agreement (LOA). There was also a significant difference between SAPd and mean arterial pressure (MAP) on oscillometric modes A (P = 0.002) and B (P <0.001). Both modes’ MAP readings were lower than SAPd and oscillometric A MAP was closer to SAPd (–14.94 mmHg), with a smaller bias and narrower LOA. Conclusions and relevance The findings support that Doppler and oscillometric devices cannot be used interchangeably, with or without proprietary optimisations. Methodology should always be taken into account and reference intervals (RIs) need to be defined for the different methodologies. Until methodology-specific RIs are published, definitive diagnosis of hypertension and sub-staging of patients with kidney disease according to the International Renal Interest Society guidelines remains challenging

A New Approach to Validate the Use of Brachial Blood Pressure to Assess Non-Invasive Aortic Pressure in Human Beings

Introduction: It has been demonstrated that the noninvasive evaluation of aortic blood pressure has a prognostic value but limited by the inaccuracy linked to technical errors and a differences in the pressure wave analysis.Aims: The aim of this study was to compare two methods used to validate the non-invasively central blood pressure waveforms obtained with an oscillometic device, with those recorded by intra-arterial measurements at the aortic level.Methods: In this study were included 20 subjects, 10 males (68 ± 12-years-old, BMI: 27.4 ± 4.6 Kg/m2) and 10 females (77 ± 8-years-old, BMI: 28.5 ± 5.3 Kg/m2). The analysed cohort was composed of patients with diagnosis of coronary artery disease. Invasive and non-invasive dataused in this research were previously analysed using a widely reported methodology and published by our group.The invasive aortic pressure recording was synchronically acquired with an oscillometric brachial acquisition and, then a reconstruction of central pressure wave was performed.In this research a correlation analysis using the entire aortic pressure cycle was performed.Results: Coefficient values found of the whole population, using the entire aortic pressure cycle, were similar to those obtained using the mean value of the cBP cardiac cycle was analysed (0.88 versus 0.89; respectively). On the contrary, the slope of the regression line determined by invasiveversus non-invasive cBP loops (n = 20) using the entire cBP cycle exhibit a remarkable decrease with respect to that obtained using the mean aortic pressure cycle (0.98 versus 0.77).Conclusions: In a first step, applying an interpolation procedure by means of oversampling and digital low pass filter, we found a high correlation between invasive and noninvasive instantaneous aortic pressure waveforms in: Men, women and the whole population, In a second step, resultsin terms of correlation coefficient and the slope derived from the regression analysis of invasive and non-invasive using a new data analysis allow to confirm high correlation coefficients and a more realistic slope value of the invasive versus non-invasive pressure wave relationship.Fil: Pessana, Franco Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Medicina Traslacional, Trasplante y Bioingeniería. Fundación Favaloro. Instituto de Medicina Traslacional, Trasplante y Bioingeniería; ArgentinaFil: Sanchez, Ramiro. Fundación Favaloro; ArgentinaFil: Lev, Gustavo. Fundación Favaloro; ArgentinaFil: Mirada, Micaela. Fundación Favaloro; ArgentinaFil: Mendiz, Oscar. Fundación Favaloro; ArgentinaFil: Ramírez, Agustín José. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Medicina Traslacional, Trasplante y Bioingeniería. Fundación Favaloro. Instituto de Medicina Traslacional, Trasplante y Bioingeniería; ArgentinaFil: Cabrera Fischer, Edmundo Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Medicina Traslacional, Trasplante y Bioingeniería. Fundación Favaloro. Instituto de Medicina Traslacional, Trasplante y Bioingeniería; Argentin

Mobile Personal Healthcare System for Non-Invasive, Pervasive and Continuous Blood Pressure Monitoring: A Feasibility Study

Background: Smartphone-based blood pressure (BP) monitor using photoplethysmogram (PPG) technology has emerged as a promising approach to empower users with self-monitoring for effective diagnosis and control ofhypertension (HT). Objective: This study aimed to develop a mobile personal healthcare system for non-invasive, pervasive, and continuous estimation of BP level and variability to be user-friendly to elderly. Methods: The proposed approach was integrated by a self-designed cuffless, calibration-free, wireless and wearable PPG-only sensor, and a native purposely-designed smartphone application using multilayer perceptron machine learning techniques from raw signals. We performed a pilot study with three elder adults (mean age 61.3 ± 1.5 years; 66% women) to test usability and accuracy of the smartphone-based BP monitor. Results: The employed artificial neural network (ANN) model performed with high accuracy in terms of predicting the reference BP values of our validation sample (n=150). On average, our approach predicted BP measures with accuracy \u3e90% and correlations \u3e0.90 (P \u3c .0001). Bland-Altman plots showed that most of the errors for BP prediction were less than 10 mmHg. Conclusions: With further development and validation, the proposed system could provide a cost-effective strategy to improve the quality and coverage of healthcare, particularly in rural zones, areas lacking physicians, and solitary elderly populations

Accuracy of automated blood pressure measurements in the presence of atrial fibrillation: systematic review and meta-analysis

This is the author accepted manuscript. The final version is available from Springer Nature via the DOI in this recordAtrial fibrillation (AF) affects ~3% of the general population and is twice as common with hypertension. Validation protocols for automated sphygmomanometers exclude people with AF, raising concerns over accuracy of hypertension diagnosis or management, using out-of-office blood pressure (BP) monitoring, in the presence of AF. Some devices include algorithms to detect AF; a feature open to misinterpretation as offering accurate BP measurement with AF. We undertook this review to explore accuracy of automated devices, with or without AF detection, for measuring BP. We searched Medline and Embase to October 2018 for studies comparing automated BP measurement devices to a standard mercury sphygmomanometer contemporaneously. Data were extracted by two reviewers. Mean BP differences between devices and mercury were calculated, where not reported and compared; meta-analyses were undertaken where possible. We included 13 studies reporting 14 devices. Mean systolic and diastolic BP differences from mercury ranged from −3.1 to + 6.1/−4.6 to +9.0 mmHg. Considerable heterogeneity existed between devices (I 2 : 80 to 90%). Devices with AF detection algorithms appeared no more accurate for BP measurement with AF than other devices. A previous review concluded that oscillometric devices are accurate for systolic but not diastolic BP measurement in AF. The present findings do not support that conclusion. Due to heterogeneity between devices, they should be evaluated on individual performance. We found no evidence that devices with AF detection measure BP more accurately in AF than other devices. More home or ambulatory automated BP monitors require validation in populations with AF.National Institute for Health Research (NIHR

Improved diagnostic accuracy for hypertension

Practical and accurate blood pressure (BP) measurement techniques are needed to ensure adequate diagnostics and treatment of hypertension. Recently, novel monitors have appeared on the market including timer-equipped home monitors and standalone noninvasive central BP monitors. The aim of this study was to clarify how BP measures obtained with these novel measurement methods compare to current measurement methods, and whether they could improve the diagnostics for hypertensive end-organ damage compared with conventional measurements in a cardiovascular substudy (N=290) of the Finnish population-based DILGOM study. Participants underwent 24-hour ambulatorymonitoring, office BP measurements, and daytime and night-time home measurements. Hypertensive end-organ damage was assessed with pulse wave velocity (PWV) measurements, carotid intima-media thickness (IMT) and left ventricular mass index (LVMI). The participants preferred office BP measurement, while ambulatory monitoring was the least acceptable method. Mean night-time BP levels were comparable between ambulatory and home monitoring, and the agreement between the methods in detecting night-time hypertension was substantial. Instead, the agreement in detecting nondipping patterns was weak. Home and ambulatory night-time BP values correlated similarly with end-organ damage, except that there was a slightly stronger correlation between ambulatory systolic BP (SBP) and PWV compared with corresponding home BP. Surprisingly, we found that brachial SBP and pulse pressure were similarly or even more strongly correlated to end-organ damage than the corresponding noninvasive central measures. To conclude, home night-time monitoring is a convenient, accurate, wellaccepted and widely available alternative to ambulatory monitoring in detecting night-time hypertension. In comparison to measurements with conventional office BP, estimated central hemodynamics with a novel stand-alone monitor do not seem to improve the diagnostics of end-organ damage.Verenpaineen uudet mittausmenetelmät Kohonneen verenpaineen asianmukaista diagnosointia ja hoitoa tarvitaan käytännöllisiä ja tarkkoja mittausmenetelmiä. Useita uusia mittareita on ilmaantunut markkinoille, mukaan lukien ajastimella varustetut kotimittarit sekä mittarit, joilla pystytään arvioimaan kajoamattomasti sentraalista eli aortan ja suurten suonten verenpainetta. Väitöskirjan tarkoituksena oli selvittää, miten nämä uudet mittaustavat vertautuvat perinteisiin menetelmiin ja parantavatko ne kohde-elinvaurioiden diagnostiikkaa verrattuna perinteisiin menetelmiin suomalaisessa DILGOM-väestötutkimuksen sydän- ja verisuonitutkimusalaryhmässä (N=290). Tutkimushenkilöille tehtiin verenpaineen vuorokausirekisteröinti, mittaukset vastaanotolla sekä kotona päivä- ja yöaikaan. Verenpaineen pääte-elinvaurioiden arviointiin käytettiin pulssiaallon nopeutta, kaulasuonten intima-media paksuutta ja vasemman kammion massaindeksiä. Tutkittavat pitivät eniten verenpaineen mittaamisesta vastaanotolla ja vähiten verenpaineen vuorokausirekisteröinnistä. Vuorokausirekisteröinnillä ja kotimittarilla mitatut yölliset verenpainetasot vastasivat hyvin toisiaan ja yhteneväisyys yöllisen kohonneen verenpaineen diagnosoinnissa menetelmien välillä oli huomattavan hyvä. Sitä vastoin verenpaineen poikkeavan päivä-yövaihtelun diagnostinen yhteneväisyys menetelmien välillä oli heikko. Mittausmenetelmästä riippumatta yöllisen verenpaineen yhteys pääte-elinvaurioihin oli samankaltainen lukuun ottamatta pulssiaallon nopeutta, minkä yhteys vuorokausirekisteröinnin kanssa oli hieman kotimittausta vahvempi. Yllättäen olkavarresta mitattu verenpaine oli yhtä hyvin ja osin jopa vahvemmin yhteydessä pääte-elinvaurioihin kuin kajoamattomasti mitattu sentraalinen verenpaine. Yhteenvetona todetaan, että verenpaineen yöaikainen mittaus kotimittarilla on käytännöllinen, tarkka, miellyttävä ja laajasti saatavilla oleva vaihtoehto verenpaineen vuorokausirekisteröinnille yöaikaisen kohonneen verenpaineen todentamiseen. Kajoamattoman sentraalisen verenpaineen arvioiminen tutkimuksessa käytetyllä helppokäyttöisellä automaattimittarilla ei näytä tuovan lisäetua pääteelinvaurioiden diagnostiikassa tavanomaiseen vastaanotolla olkavarresta mitattuun verenpaineeseen verrattuna

Blood pressure in atrial fibrillation

Introduction: Hypertension is a leading risk factor for cardiovascular morbidity and premature death. Prevalence of hypertension in the adult population in Sweden has been estimated to 27%. Atrial fibrillation (AF) is the most prevalent sustained arrhythmia of clinical relevance with an estimated prevalence of at least 2.9% among adults in Sweden. Similarly to hypertension, AF is independently associated with an increased risk for cardiovascular morbidity and with a two-fold increased risk of death. The underlying mechanisms responsible for this association however, are not fully known. Both conditions may impose a heavy burden upon affected patients as well as on the health care system. AF and hypertension are closely intertwined and often coexist. Hypertension is the major risk factor for AF development and conversely, AF affects blood pressure (BP). The irregular heart rhythm in AF is one factor influencing BP, but also other factors may play a part. Furthermore, the presence of AF has implications for conventional BP measurement. AF-related effects on BP are studied to a very limited extent. Possibly, AF-induced BP effects may have pathophysiological consequences and may also influence BP measurement accuracy. Consequently, these factors may negatively influence risk assessment and prognosis in patients with AF. The aims of this thesis were 1) to systematically quantify beat-to-beat BP variability in patients with AF compared to sinus rhythm (SR); 2) to study how BP, as measured with different techniques, is affected by the presence of AF; 3) to investigate the relationship between peripheral and central intra-arterial BP, in patients with AF compared to SR; 4) to evaluate the accuracy of conventional BP measurement in relation to peripheral and central intra-arterial BP, in patients with AF and compared to SR. Methods and results: In the prospective study I, patients scheduled for a coronary angiography were recruited. Participants included 21 patients in AF and 12 patients with SR. Intra-arterial BP was recorded from the radial and brachial artery and from the ascending aorta. The primary outcome measure was beat-to-beat BP variability, defined as average systolic and diastolic BP difference between consecutive beats, at each site of measurement. A significant difference (p<0.001) in BP variability, in AF compared to SR, was observed for all locations of measurement. Systolic BP variability was roughly doubled in patients with AF (4.9 vs 2.4 mmHg), whereas diastolic BP variability was approximately six times as high (7.5 vs 1.2 mmHg) in patients with AF compared to SR. Study II was a retrospective registry analysis based on data from electronic medical records. 487 patients, treated with electrical cardioversion (ECV) for persistent AF, were included in the study. Information regarding auscultatory sphygmomanometric BP and rhythm, on the day before and 7 days after ECV, was obtained. The primary outcome measure was BP change in patients with restored SR after ECV. In this group with restored SR, systolic BP increased by 9 mmHg (p<0.01), whereas diastolic BP decreased by 3 mmHg (p<0.01). Furthermore, the proportion of patients with a hypertensive BP-level (≥140/90) increased by 40% in this group. In study III, 98 patients with persistent AF undergoing ECV were prospectively recruited. BP was evaluated with 24-h ambulatory BP monitoring before and approximately one week after ECV. The primary outcome measure was BP change in patients with restored SR after ECV. Among 60 patients maintaining SR, mean systolic 24-h ambulatory BP increased by 5.6 mmHg (p<0.001) and mean diastolic 24-h ambulatory BP decreased by 4.7 mmHg (p<0.001). Accordingly, a 10.4 mmHg (25%) increase in pulse pressure was observed among patients with restored SR. Study IV comprised the same individuals as study I. Conventional BP (auscultatory sphygmomanometric and automated oscillometric) and intra-arterial BP was measured simultaneously. The first aim was to investigate how intra-arterial BP changes throughout the arterial tree in patients with AF in comparison to patients in SR. The second aim was to evaluate the accuracy of conventional BP measurement in patients with AF in comparison to central and peripheral intra-arterial BP, and in comparison to patients in SR. BP changes throughout the arterial tree was similar in patients with AF compared to SR. Conventional BP was in general very accurate in comparison to diastolic intra-arterial BP, both in AF and SR. In patients with AF, oscillometric blood pressure overestimated systolic intra-arterial brachial (4.1 mmHg, p=0.07) and central (5.0 mmHg, p=0.04) BP. With measurement bias in SR taken into account, oscillometric BP over-estimated systolic intra-arterial brachial BP by 14.1 mmHg (p<0.01) and central BP by 9.0 mmHg (p=0.01) in patients with AF. Conclusions: Beat-to-beat BP variability is increased in patients with AF compared to SR. According to the results from studies in this thesis, systolic BP is lower and diastolic BP is higher in AF compared to SR, as measured by auscultatory sphyghmomanometry or by oscillometric 24-h ambulatory BP monitoring. As a consequence, pulse pressure is markedly lower in AF compared to SR. Intra-arterial BP change throughout the arterial tree is similar in patients with AF and SR. Conventional BP measurement was accurate in relation to diastolic intra- arterial BP, but oscillometric BP measurement overestimated intra-arterial brachial and central systolic BP in patients with AF, in particular when compared to patients in SR. The presence of AF affects BP. This may have implications for the accuracy of conventional BP measurement and may possibly also have pathophysiological consequences. Suboptimal understanding, measurement and treatment of BP may negatively influence prognosis in patients with AF

Comparison Between Invasive and Noninvasive Methods to Estimate Subendocardial Oxygen Supply and Demand Imbalance

Background Estimation of the balance between subendocardial oxygen supply and demand could be a useful parameter to assess the risk of myocardial ischemia. Evaluation of the subendocardial viability ratio (SEVR, also known as Buckberg index) by invasive recording of left ventricular and aortic pressure curves represents a valid method to estimate the degree of myocardial perfusion relative to left ventricular workload. However, routine clinical use of this parameter requires its noninvasive estimation and the demonstration of its reliability. Methods and Results Arterial applanation tonometry allows a noninvasive estimation of SEVR as the ratio of the areas directly beneath the central aortic pressure curves obtained during diastole (myocardial oxygen supply) and during systole (myocardial oxygen demand). However, this "traditional" method does not account for the intra-ventricular diastolic pressure and proper allocation to systole and diastole of left ventricular isometric contraction and relaxation, respectively, resulting in an overestimation of the SEVR values. These issues are considered in the novel method for SEVR assessment tested in this study. SEVR values estimated with carotid tonometry by "traditional" and "new" method were compared with those evaluated invasively by cardiac catheterization. The "traditional" method provided significantly higher SEVR values than the reference invasive SEVR: average of differences +/- SD= 44 +/- 11% (limits of agreement: 23% - 65%). The noninvasive "new" method showed a much better agreement with the invasive determination of SEVR: average of differences +/- SD= 0 +/- 8% (limits of agreement: -15% to 16%). Conclusions Carotid applanation tonometry provides valid noninvasive SEVR values only when all the main factors determining myocardial supply and demand flow are considered