Δευτέρα, 19 Αυγούστου 2019

Urinary catecholamines during stress and ambulatory blood pressure in children born full term but small for gestational age: a pilot study
Objectives: Increased sympathetic activity is proposed to be a mechanism of high blood pressure in children born small for gestational age. Ambulatory blood pressure monitoring is a form of blood pressure measurement that can detect high blood pressure outside the hospital in patients with normal office blood pressure. This condition is called masked hypertension. There are limited data on association between ambulatory blood pressure and urinary catecholamines during exposure to stress in children born small for gestational age. Methods: Nineteen children born small for gestational age and 17 healthy controls ages 6–14 years old were included. Demographic data and office blood pressure were collected. Urinary catecholamines were collected before and after exposure to stress including mathematical test and venipuncture. Afterwards, ambulatory blood pressure monitoring was performed to obtain 24-hour blood pressure profiles. Results: All children had normal office blood pressure but ambulatory blood pressure monitoring revealed masked hypertension in six children born small for gestational age (32%) and two controls (11.7%). After stress, median percentage of increase in urine norepinephrine levels was greater in children born small for gestational age with masked hypertension than that of children born small for gestational age without masked hypertension (9.2 vs. −13.2 μg/g creatinine, P = 0.05). There was no increase in urine norepinephrine levels in controls with masked hypertension. Among children born small for gestational age, awake SBP z-scores had significant positive correlations with pre- and post-stress urinary dopamine levels (r = 0.530, P = 0.02 and r = 0.597, P = 0.007, respectively). Conclusion: Masked hypertension is not uncommon in children born small for gestational age. After stress, urinary norepinephrine levels were increased in children born small for gestational age with masked hypertension. Received 6 April 2019 Accepted 1 July 2019 Correspondence to Kwanchai Pirojsakul, MD, Associate Professor, Department of Pediatrics, Ramathibodi Hospital Mahidol University, Bangkok 10400, Thailand, Tel: +(66)81 697 5497; fax: +(66)2 201 1850; e-mail: kwanchai.pio@mahidol.ac.th Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.
Evaluating the performance of automated sphygmomanometers using a patient simulator
Background and objective: Automated sphygmomanometers use the oscillometric method to measure blood pressure, which is based on an algorithm that relates the amplitude of the oscillometric waveform pulses and the pressure inside the cuff. Validation uses empirical information from clinical trials conducted by each manufacturer. Consequently, measurement algorithms are not harmonized, being based on distinct arterial waveforms, according to each group of volunteers of the clinical test. In the present study, a patient simulator was used to generate standardized, consistent oscillometric waveform pulses to test the algorithms used in six sphygmomanometers. Materials and methods: Six different upper arm and wrist-based automated sphygmomanometers were tested using a patient simulator comprising four different blood pressure levels, Psys/dia (mmHg): 80/50; 120/80; 150/100; 200/150. The devices were also submitted to conformity assessment. The variance of repeatable measurements was also analyzed. Results: All tested automated sphygmomanometers complied with metrological requirements, presenting results within the range of ±2 mmHg for static calibration. Systematic discrepancies, greater than 20 mmHg, were observed between sphygmomanometers’ results from upper arm and wrist-based models. Differences reaching 12.8 mmHg in diastolic pressure results were observed among upper arm devices. Conclusion: These results may have a clinical impact and indicate the need for a standardized algorithm, with a harmonized approach for validation. Moreover, the algorithm of the wrist-based devices is being affected by the use of the brachial artery waveform as reference for its validation, which also reveals that the current approach needs standardization, especially regarding the use of patient simulators. Received 2 April 2019 Accepted 27 June 2019 Correspondence to Bruno Amado Rodrigues Filho, PhD, National Institute of Metrology, Quality and Technology–Inmetro, São Paulo Office, 1922 Santa Cruz St., São Paulo, SP 04122-002, Brazil, Tel: +551135812460; e-mail: bafilho@inmetro.gov.br Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.
Interarm blood pressure measurement and the reference-arm assignment variability
Objective The arm with the higher blood pressure (BP) is assigned as the follow up arm for hypertensive patients (reference-arm). We evaluated the reproducibility of this assignment. Methods BP was measured simultaneously on both arms with a double cuff validated device in two visits separated <10 days (two sets of three readings per visit). Two reference-arms were assigned in each visit (the arm with higher BP, at least ≥1 mmHg). The intravisit and intervisit agreements of this assignment were evaluated. Results We included 313 hypertensive patients. First visit mean right arm BP was 131.6 (16.6)/75.3 (9.4) mmHg and left arm BP was 132.4 (16.9)/75.7 (9.7) mmHg (P = 0.002). Intravisit concordance at the first and second visits were κ = 0.60 [95% confidence interval (CI), 0.516–0.696] and κ = 0.45 [95% CI, 0.356–0.555], respectively. Therefore, 21.8% of patients (at the first visit) and 29.1% (at the second visit) with the right arm as the reference-arm in the first round of readings changed to the left arm in the same visit in the second round of readings. The intervisit κ index was 0.25 [95% CI, 0.147–0.365]. After that, 36.8% of patients with the right arm as the reference-arm at the first visit changed to the left arm at the second visit. The subgroup (9.5%) with an interarm systolic BP difference ≥10 mmHg at the first visit did not differ significantly from the rest of patients. Conclusion The reference-arm assignment agreement is weak to moderate. The assignment of the reference-arm should be individualized and not considered as definitive. Received 19 March 2019 Accepted 13 June 2019 Correspondence to Ernest Vinyoles, MD, PhD, CAP La Mina, Plaça M Àngels Rossell Simplicio, s/n. 08930 – Sant Adrià de Besòs, Barcelona, Spain, Tel: + 34 933811593; fax + 34 933812141; e-mail: 23561evb@comb.cat Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.
Effects of doxazosin mesylate versus nifedipine on blood pressure variability in hypertensive patients: a randomized crossover study (SIMILAR)
Objective Blood pressure variability (BPV) is a powerful predictor of end-organ damage, cardiovascular events and mortality independently of the BP level. Calcium channel blockers may offer an advantage over other first-line antihypertensive drugs by preventing increased BPV. But the effect of alpha-receptor blockers on BPV in hypertensive patients is still unclear. Methods In this crossover trial, 36 hypertensive patients were randomly assigned to two groups, receiving doxazosin mesylate gastrointestinal therapeutic system (GITS) (4 mg/day) or nifedipine GITS (30 mg/day) for 12 weeks, followed by a 2-week washout period then a 12-week crossover phase. At baseline and after 12-week treatment, 24-hour ambulatory BP monitoring was performed. BPV was evaluated through standard deviation (SD), coefficient of variation (CV), and average real variability (ARV) of systolic BP (SBP) and diastolic BP (DBP) during daytime, nighttime and over 24 hours. Results After 12-week treatment, both doxazosin and nifedipine significantly decreased SBP and DBP (P < 0.05), whereas no between-group differences were shown (P>0.05). Systolic BPV (24-hour SD, CV, and ARV; daytime SD; nighttime SD and CV) and diastolic BPV (24-hour SD and ARV) were significantly lowered by nifedipine (P < 0.05); doxazosin resulted in significant reductions of systolic BPV (24-hour SD, CV and ARV; daytime SD; nighttime SD) and diastolic BPV (nighttime SD and CV) (P < 0.05). Doxazosin was revealed to be as effective as nifedipine for reducing BPV (P > 0.05) except for 24-hour SBP ARV. Conclusions Doxazosin mesylate GITS had similar therapeutic effects on BP, BP SD, and BP CV lowering as nifedipine GITS in patients with mild-to-moderate essential hypertension. * Drs Jing Shi, Desen Liang and Yujiao Pan contributed equally to this work. Received 12 January 2019 Accepted 17 April 2019 Correspondence to Yue Li, PhD, Cardiovascular Department, The First Affliated Hospital, Harbin Medical University, No. 23 Youzheng Street, Nangang District, Harbin, Heilongjiang 150001, People’s Republic of China, Tel: 86 451 85555673; fax: 86 451 53607428; e-mail: ly99ly@vip.163.com Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.
Relation of short-term blood pressure variability to early renal effects in hypertensive patients with controlled blood pressure
Introduction: Microalbuminuria is a common early hypertension-mediated organ damage, which correlates with the overall cardiovascular risk and development of end-stage renal damage. Lately, blood pressure variability has shown an additive value over traditional BP measurement in prediction of cardiovascular and renal involvement. Aim: Investigate the relation between short-term blood pressure variability and microalbuminuria in controlled hypertensive patients. Patients and methods: Ninety non-diabetic hypertensive patients with controlled blood pressure and normal estimated glomerular filtration rate had 24-hour ambulatory blood pressure monitoring with calculation of short-term blood pressure variability indices (SD, coefficient of variation and average reading variability of systolic and diastolic blood pressure for 24-hour, daytime and nighttime], and measurement of the albumin/creatinine ratio. Results: Patients were classified into group 1 (61 patients without microalbuminuria) and group 2 (29 patients with microalbuminuria). No significant difference was observed between both groups regarding age, sex, body mass index, office blood pressure, average 24-hour ambulatory blood pressure monitoring readings and dipping status, but significantly longer duration of hypertension in group 2. All blood pressure variability indices were significantly higher in group 2, which showed strong positive correlations with microalbuminuria level. Multivariate analysis represented an average reading variability of 24-hour systolic blood pressure as the most powerful independent predictor for microalbuminuria (r2 = 0.516, P = 0.001). Receiver operating characteristic curve analysis revealed that average reading variability of 24-hour systolic blood pressure (>12.55) could predict microalbuminuria (sensitivity = 89.7%, specificity = 88.5%, area under curve = 0.949, P = 0.001). Conclusion: Short-term blood pressure variability correlated well with early renal effects in controlled hypertensive patients. Average reading variability of 24-hour systolic blood pressure was the strongest predictor for microalbuminuria in such patients. Received 12 December 2018 Accepted 29 March 2019 Correspondence to Hazem Mohammad Ali Farrag, MD, Lecturer in Cardiology, Faculty of Medicine, Minia University, PO: 61111, Egypt, Tel: +201006387828; fax: +201202556775; e-mail: dr-hazemfarrag@hotmail.com Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.

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