Добірка наукової літератури з теми "Central blood pressure; applanation tonometry; sphygmomanometerD"

The purpose of this study was to investigate whether measures derived from the SphygmoCor device and its associated transfer function are influenced by exercise-induced alterations in vascular tone. Measurements were taken from either the exercised or the contralateral nonexercised limb during repeated and identical incremental hand-grip protocols. Eight male subjects performed three 3-min bouts of hand-grip exercise on two occasions. The exercise intensities were set at 3 kg, 5 kg, with a final 1.5-kg bout performed during cuff ischemia (1.5Isch). Blood pressure waveforms were recorded from the radial artery of either the exercised or nonexercised limb using applanation tonometry (SphygmoCor) during a 90-s rest period immediately after each exercise bout. Central blood pressures and augmentation indexes (AIx), an index of arterial stiffness, were derived using the peripheral waveform and the inbuilt SphygmoCor transfer function (TF). AIx was consistently ∼10% higher in the exercised arm during all trials compared with the nonexercised limb. Similarly, there was a consistent and significant difference (∼3 mmHg; P < 0.05) between exercised and nonexercised arms for the derived central systolic and mean arterial blood pressures. Despite identical bouts of exercise, AIx and central systolic and mean arterial blood pressures derived from applanation tonometry at the peripheral radial artery were statistically different when assessed at the exercising arm vs. the nonexercising arm. Changes in vascular tone with exercise may modify the intrinsic characteristics of the vessel wall and could compromise the assumptions underlying transfer functions used to derive central measures using applanation tonometry.

Background: bronchodilators are the major class of drugs prescribed for chronic obstructive pulmonary disease (COPD). Meanwhile, treatment strategies for obstructive lung disease using bronchodilators are continually discussed and reviewed, in particular, with regard to their potential effect on cardiovascular system. Aim: to evaluate the effect of the combination of a short-acting β2-agonist plus an anticholinergic medication (fenoterol 50 μg/dose + ipratropium bromide 20 μg/dose, 2 doses) on the efficacy of coronary blood flow in COPD patients. Patients and Methods: spirometry with bronchodilator testing (at least 12 hours after using the medication) was performed in 30 COPD patients. The efficacy of coronary blood flow was assessed by central subendocardial viability ratio (C_SEVR) measured by applanation tonometry which was performed before and 15, 30, and 60 min after using the bronchodilator. Oxygen saturation was measured at all stages of the study. Results: the combination of fenoterol and ipratropium bromide resulted in the increase of C_SEVR by 9.5 [3.3; 10.8]% in patients with low oxygen saturation at baseline due to heart rate reduction, diastolic lengthening, and oxygen level improvement. The timing of the effect was determined by the reversibility of bronchial obstruction. No effects of the combination of fenoterol and ipratropium bromide on central and peripheral blood pressure were reported. Conclusion: low oxygen saturation at baseline and reversible bronchial obstruction in COPD patients allow for a favorable predicted systemic effect of the combination of fenoterol and ipratropium bromide. When using in therapeutic dosages and according to recommended dosage regimen, this combination improves bronchopulmonary function, oxygen saturation, and the efficacy of coronary blood flow measured by applanation tonometry. KEYWORDS: chronic obstructive pulmonary disease, applanation tonometry, central subendocardial viability ratio, SEVR, bronchial obstruction, oxygen saturation. FOR CITATION: Punin D.A. Effect of the combination of a short-acting β2-agonist plus an anticholinergic drug on the efficacy of coronary blood flow measured by applanation tonometry in chronic obstructive pulmonary disease. Russian Medical Inquiry. 2020;4(4):199–206. DOI: 10.32364/2587-6821-2020-4-4-199-206.

Augmentation index (AIx) and pulse wave velocity (PWV) assess functional and structural aspects of the vascular wall and are independent markers of cardiovascular morbidity and mortality. Like blood pressure, many factors, genetic, structural, and physiological, affect AIx and PWV. AIx and PWV can be assessed noninvasively using applanation tonometry. The technique is simple, but comes with a number of practical and technical limitations that have not been well documented and (or) explored. This review considers pulse wave analysis in the context of cardiovascular disease, and considers its limitations. Data are presented indicating that the placement of the probe is critical, and that the amplitude of the obtained signal is related to the variability in measurements. On a more theoretical note, issues are discussed regarding the applied transfer functions that are built in the devices to assess central AIx from peripheral waveforms. Altogether, PWV and its analysis are useful additions to the arsenal of parameters that can be used to assess vascular health and to estimate vascular risk. Yet, our analysis underscores the necessity for precise operating procedures, and calls for transparency regarding the applied transfer functions of commercial devices.

Aim: to evaluate the effect of renal denervation (RDN) on the stiffness of the aorta and major arteries, central blood pressure and index augmentation in patients with resistant hypertension. Material and methods. We included 20 patients with systolic blood pressure 178 [170; 180] mm Hg and diastolic blood pressure 100 [94; 100] mm Hg on 5.1±0.7 antihypertensive drugs with diuretic, who underwent bilateral RDN. Blood pressure (BP) was studied before intervention, at 7 days and 6 months after RDN by tree methods: office BP, 24-hour ambulatory blood pressure (ABPM) and aortic BP with applanation tonometry a. radialis (SphygmoCor). All patients were divided into two groups by ABPM in 6 months after RDN: responders (decrease of mean ABPM≥5 mm Hg) and non-responders (decrease of mean ABPM

Background and aim: Systemic lupus erythematosus (SLE) is associated with increased risk of cardiovascular disease (CVD). Among many mechanisms, accelerated atherosclerosis, endothelial dysfunction, and hypercoagulability play a main role. Here, we investigate whether inflammatory, serological and clinical markers of SLE determine and correlate with arterial stiffness in SLE patients. Materials and methods: Routine blood samples, inflammatory mediators, specific antibodies, and 24 h proteinuria were measured in 43 SLE patients and 43 age and sex-matched controls using routine laboratory assays. We also assessed arterial stiffness by measuring radial artery applanation tonometry-derived augmentation index (AI), normalized AI (AIx@75), aortic pulse pressure, central systolic, diastolic and peripheral blood pressure. Results: SLE patients showed a significantly greater arterial stiffness vs. controls, as demonstrated by the significantly higher AIx@75 and aortic pulse pressure. Interestingly, regression analysis showed that age, systolic pulse pressure, inflammatory markers (erythrocyte sedimentation rate and C-reactive protein), daily dose of glucocorticoids, and cumulative organ damage positively correlated with arterial stiffness. Conclusions: SLE patients show increased arterial stiffness which correlates with markers of inflammation, that is involved in early alterations in arterial walls. Applanation tonometry can be used to screen SLE patients for subclinical vascular damage to implement prevention strategies for CVD.

The aim of our study was to investigate the association between pulse wave velocity (PWV) and pulse wave analysis (PWA)-derived measurements for the evaluation of arterial stiffness. A total of 20 (7 male and 13 female) healthy, non-smoking individuals, with mean age 31 ± 12years were included. PWV and PWA measurements were performed using a SphygmoCor apparatus (Atcor Medical Blood Pressure Analysis System, Sydney Australia). PWV significantly correlated with all central aortic haemodynamic parameters, especially with pulse pressure (PP) (p < 0.0001), augmentation index corrected for 75 pulses/min (AI75) (p = 0.035) and augmentation pressure (AP) (p = 0.005). Male subjects presented significantly higher PWV compared with females (p = 0.03), while there were no differences in PP, AP and AI75. In conclusion, PWA is strongly correlated with PWV as a method for the evaluation of arterial stiffness.

Recently, novel concepts and medical technologies have developed rapidly with enormous growth and unprecedented expansion in the range of interventions and knowledge offered for health professionals in their clinical decision making. This burgeoning innovation has not necessarily resulted in an incremental availability of knowledge to policymakers and clinicians. In this study critical translation gaps have been addressed strategically in the research-into-action cycle to improve outcomes and services. Given widespread acceptance that waveform morphology and blood pressure (BP) differ considerably between the central aorta and peripheral arterial system, it is clear that BP measurements in the peripheral arteries cannot serve as direct substitutes for their central counterparts. Although non-invasive BP measured in the brachial artery (cuff BP) is the basis for the present management of hypertension, central blood pressure (CBP) has been shown to be the better predictor of cardiovascular outcomes than cuff BP. Consequently, there are substantial research efforts to develop non-invasive estimating methods for CBP, mainly based on the technique of applanation tonometry. However, CBP measured has not been widely adopted in clinical practice. One of the possible gaps is that tonometry-based measurement requires some skills and time to perform and it is a relatively expensive technique. Besides, the accuracy of the current tonometry-based techniques has been questioned. To identify and address the gaps of translating the evidence of the importance of CBP, a series of studies were conducted. To identify existing gaps, I carried out a systematic review and meta-analysis of studies comparing tonometry-based CBP estimates with invasively measured central BP and found that present tonometry-based CBP estimating methods are acceptable in theory, with small errors. However, there is substantial room for improvement in measurement accuracy of CBP. To develop a more accurate, less expensive, and less technically dependent CBP measurement technique, the pulse wave analysis (PWA) technique for brachial pulse volume plethysmography (PVP) waveforms from an oscillometric blood pressure monitor was implemented. Evaluation demonstrated that large random and systematic errors are introduced into the central pulse pressure (PP) estimates when they are calculated as the difference between the estimated central systolic BP (SBP) and central or cuff diastolic BP (DBP), which can be improved substantially with the novel PWA approach. Subsequently, the novel technique was seamlessly incorporated into a standalone automatic BP monitor. In a rigorous validation study, it was demonstrated that CBP can be measured accurately by this stand-alone automatic blood pressure monitor. To apply the CBP concept in clinical practice, the gap between innovation and clinical application should be closed. The diagnostic threshold for confirming a diagnosis of hypertension with CBP has never been proposed; I therefore derived and validated the diagnostic threshold of CBP based on two independent event-based cohorts with long-term follow-up. With the proposed cut-off limits for the diagnosis of hypertension, the diagnostic accuracy of the stand-alone CBP monitor reference to invasively measured CBP was estimated. It was then suggested that traditional cuff BP may be reliable in confirming the diagnosis of hypertension and in justifying subsequent treatment with its high specificity. However, because of low sensitivity, the cuff BP could render possible management inaccessible to a considerable proportion of hypertensive subjects, who may be identifiable through the noninvasive CBP monitor. Finally, in responding to the gap between clinical application and policy, a health economic evaluation was required to support the cost-effectiveness of the new emerging technique. A comprehensive Markov modelling was performed and this confirmed the cost-effectiveness of CBP monitoring, which resulted from a greater quality gain that outweighed its supplementary cost. Given more data supporting the diagnostic and prognostic role of CBP, it should be considered to be an effective strategy for the management of hypertension.
Thesis (Ph.D.) -- University of Adelaide, School of Translational Health Science, 2013