Assessment of the DIXTAL DX-2710 automated oscillometric device for blood pressure measurement with the validation protocols of the British Hypertension Society (BHS) and the Association for the Advancement of Medical Instrumentation (AAMI)

Oral Fludrocortisone Test for Salt-Sensitive Screening in Hypertensive Patients: A Randomized Crossover Trial

Background

Salt sensitivity is associated with an increased cardiovascular risk, but the gold standard method (diet cycles) requires 24-h urine samples and has poor patient compliance.

Objectives

Test the hypothesis that oral fludrocortisone (0.4 mg per day for 7 days) is a good alternative in identifying salt-sensitive patients.

Methodology

We conducted a randomized crossover study with 30 hypertensive individuals comprising the following steps: (1) washout; (2) phase A (low- and high-sodium diet cycles); (3) washout 2; (4) phase B (fludrocortisone test). Phase A and B steps were performed in a random way. Consistent with the literature, we found that 53.3% were salt-sensitive according to the reference test. Using the ROC curve, the fludrocortisone test defined salt sensitivity by a median blood pressure increase of ≥3 mmHg. A good accuracy of fludrocortisone in detecting salt sensitivity was observed (AUC: 0.732±0.065; p<0.001), with 80% sensitivity and 53% specificity.

Conclusion

The fludrocortisone test is a good option for screening salt sensitivity in hypertensive patients. However, the low specificity prevents this test from being an ideal substitute to the labor-intensive diet cycles exam in the definition of salt sensitivity. This clinical trial is registered with NCT01453959.

Effects of long term device-guided slow breathing on sympathetic nervous activity in hypertensive patients: a randomized open-label clinical trial

PURPOSE

Device-guided slow breathing (DGB) is indicated as nonpharmacological treatment for hypertension. The sympathetic nerve activity (SNA) reduction may be one of the mechanisms involved in blood pressure (BP) decrease. The aim of this study is to evaluate the long-term use of DGB in BP and SNA.

SUBJECTS AND METHODS

Hypertensive patients were randomized to listen music (Control Group-CG) or DGB (aim to reduce respiratory rate to less than 10 breaths/minute during 15 minutes/day for 8 weeks). Before and after intervention ambulatory blood pressure monitoring (ABPM), catecholamines and muscle sympathetic nerve activity (MSNA) by microneurography were performed.

RESULTS

17 volunteers in the DGB and 15 in the CG completed the study. There was no change in office BP before and after intervention in both groups. There was a reduction in systolic and diastolic BP in the awake period by ABPM only in the CG (131 ± 10/92 ± 9 vs 128 ± 10/88 ± 8mmHg, p < 0.05). In relation to SNA, no difference in catecholamines was observed. In the volunteers who had a microneurography record, there was no change the MSNA (bursts/minute): DGB (17(15-28) vs 19(13-22), p = 0.08) and CG (22(17-23) vs 22(18-24), p = 0.52).

CONCLUSION

Long-term DGB did not reduce BP, catecholamines levels or MSNA in hypertensive patients. ClinicalTrials.gov identifier: NCT01390727.

Peripheral Vascular Resistance Impairment during Isometric Physical Exercise in Normotensive Offspring of Hypertensive Parents

BACKGROUND:

A family history of hypertension is associated with vascular and autonomic abnormalities, as well as an impaired neurohemodynamic response to exercise.

OBJECTIVE:

To test the hypothesis that normotensive individuals with a family history of hypertension present an impaired peripheral vascular resistance response to exercise.

METHODS:

The study included 37 normotensive volunteers of both sexes who were sedentary, eutrophic, and nonsmokers, comprising 23 with (FH+; 24 ± 3 years) and 14 without (FH-; 27 ± 5 years) a family history of hypertension. Blood pressure, heart rate (DIXTAL®), forearm blood flow (Hokanson®), and peripheral vascular resistance were simultaneously measured for 3 minutes during rest and, subsequently, for 3 minutes during an isometric exercise at 30% of maximal voluntary contraction (Jamar®).

RESULTS:

At rest, the FH+ and FH- groups present similar mean blood pressure (83 ± 7 versus 83 ± 5 mmHg, p = 0.96), heart rate (69 ± 8 bpm versus 66 ± 7 bpm, p = 0.18), forearm blood flow (3 ± 1 mL/min/100 mL versus 2.7 ± 1 mL/min/100 mL, p = 0.16), and peripheral vascular resistance (30 ± 9 units versus 34±9 units, p = 0.21), respectively. Both groups showed a significant and similar increase in mean blood pressure (∆ = 15 ± 7 mmHg versus 14 ± 7 mmHg, p = 0.86), heart rate (∆ = 12 ± 8 bpm versus 13 ± 7 bpm, p = 0.86), and forearm blood flow (∆ = 0.8 ± 1.2 mL/min/100 mL versus 1.4 ± 1.1 mL/min/100 mL, p = 0.25), respectively, during exercise. However, individuals in the FH+ group showed no reduction in peripheral vascular resistance during exercise, which was observed in the FH- group (∆ = -0.4 ± 8.6 units versus -7.2 ± 6.3 units, p = 0.03).

CONCLUSION:

Normotensive individuals with a family history of hypertension present an impaired peripheral vascular resistance response to exercise.

FUNDAMENTO:

O histórico familiar para hipertensão arterial está relacionado a anormalidades vasculares e autonômicas, bem como disfunções no comportamento neuro-hemodinâmico durante o exercício físico.

OBJETIVO:

Testar a hipótese de que indivíduos normotensos com histórico familiar de hipertensão arterial apresentam resposta prejudicada da resistência vascular periférica durante o exercício físico.

MÉTODOS:

Foram avaliados 37 normotensos de ambos os sexos, sedentários, eutróficos e não tabagistas, sendo 23 com histórico familiar positivo (HF+, 24 ± 3 anos) e 14 com histórico familiar negativo (HF-, 27 ± 5 anos) para hipertensão arterial. Foram identificados pressão arterial, frequência cardíaca (DIXTAL®), fluxo sanguíneo muscular do antebraço e resistência vascular periférica local (Hokanson®) por 3 minutos durante o repouso e, em seguida, 3 minutos durante exercício isométrico de preensão palmar a 30% da contração voluntária máxima (Jamar®).

RESULTADOS:

Em repouso, os grupos HF+ e HF- apresentaram valores semelhantes de pressão arterial média (83 ± 7 mmHg versus 83 ± 5 mmHg, p = 0,96), frequência cardíaca (69 ± 8 bpm versus 66 ± 7 bpm, p = 0,18), fluxo sanguíneo muscular (3 ± 1 mL/min/199 mL versus 2,7 ± 1 mL/min/100 mL, p = 0,16) e resistência vascular periférica (30 ± 9 unidades versus 34 ± 9 unidades, p = 0,21), respectivamente. Durante o exercício, HF+ e HF- mostraram aumento significativo e semelhante da pressão arterial média (∆ = 15 ± 7 mmHg versus 14 ± 7 mmHg, p = 0,86), frequência cardíaca (∆ = 12 ± 8 bpm versus 13 ± 7 bpm, p = 0,86) e fluxo sanguíneo muscular (∆ = 0,8 ± 1,2 mL/min/100 mL versus 1,4 ± 1,1 mL/min/100 mL, p = 0,25), respectivamente. Entretanto, no grupo HF+ não houve redução significativa da resistência vascular periférica durante o exercício, fato que ocorreu no grupo HF- (∆ = -0,4 ± 8,6 unidades versus -7,2 ± 6,3 unidades, p = 0,03).

CONCLUSÃO:

Indivíduos normotensos com histórico familiar de hipertensão arterial apresentam resposta prejudicada da resistência vascular periférica durante o exercício físico.

[Home blood pressure monitoring: updates and the nurse's role]

This is a review article on home blood pressure monitoring (HBPM) developed with the purpose to increase the current scientific knowledge and present the importance of this approach in the care to patients with hypertension in our setting. This technique has advantages over the causal measurement, as it provides more measurements, a better relationship with the target-organs injuries, it also quantifies the white-coat effect, has good reproducibility, good acceptability by the patients, assesses blood pressure without the influence from the observer and the environment of the appointment, reduces the number of visits to the doctor and promotes greater adherence to treatment. The importance of nursing practice in HBPM is associated with the education process, using teaching-learning strategies, implementing team-patient communication and encouraging patients towards performing self-care.

Home blood pressure (BP) monitoring in kidney transplant recipients is more adequate to monitor BP than office BP

BACKGROUND

Hypertension is highly prevalent among kidney transplantation recipients and considered as an important cardiovascular risk factor influencing patient survival and kidney graft survival. Aim. Compare the blood pressure (BP) control in kidney transplant patients through the use of home blood pressure monitoring (HBPM) is more comparable with the results of ambulatory blood pressure monitoring compared to the measurement of office blood pressure.

METHODS

From March 2008 to April 2009 prospectively were evaluated 183 kidney transplant recipients with time after transplantation between 1 and 10 years. Patients underwent three methods for measuring BP: office blood pressure measurement (oBP), HBPM and ambulatory blood pressure monitoring (ABPM).

RESULTS

In total, 183 patients were evaluated, among them 94 were men (54%) and 89 women (46%). The average age was 50 ± 11 years. The average time of transplant was 57 ± 32 months. Ninety-nine patients received grafts from deceased donors (54%) and 84 were recipients of living donors (46%). When assessed using oBP, 56.3% presented with uncontrolled and 43.7% with adequate control of BP with an average of 138.9/82.3 ± 17.8/12.1 mmHg. However, when measured by HBPM, 55.2% of subjects were controlled and 44.8% presented with uncontrolled BP with an average of 131.1/78.5 ± 17.4/8.9 mmHg. Using the ABPM, we observed that 63.9% of subjects were controlled and 36.1% of patients presented uncontrolled BP with an average 128.8/80.5 ± 12.5/8.1 mmHg. We found that the two methods (oBP and HBPM) have a significant agreement, but the HBPM has a higher agreement that oBP, confirmed P = 0.026. We found that there is no symmetry in the data for both methods with McNemar test. The correlation index of Pearson linear methods for the ABPM with the other two methods were 0.494 for office measurement and 0.768 for HBPM, best value of HBPM with ABPM. Comparing the errors of the two methods by paired t-test, we obtained the descriptive level of 0.837. Looking at the receiver operating characteristic curve for BP measurements in each method, we observed that oBP is lower than those obtained by HBPM in relation to ABPM.

CONCLUSION

We conclude that the results obtained with HBPM were closer to the ABPM results than those obtained with BP obtained at oBP, being more sensitive to detect poor control of hypertension in renal transplant recipients.

How to avoid discontinuation of antihypertensive treatment: The experience in São Paulo, Brazil

OBJECTIVES

To evaluate the importance of providing guidelines to patients via active telephone calls for blood pressure control and for preventing the discontinuation of treatment among hypertensive patients.

INTRODUCTION

Many reasons exist for non-adherence to medical regimens, and one of the strategies employed to improve treatment compliance is the use of active telephone calls.

METHODS

Hypertensive patients (n=354) who could receive telephone calls to remind them of their medical appointments and receive instruction about hypertension were distributed into two groups: a) "uncomplicated" - hypertensive patients with no other concurrent diseases and b) "complicated" - severe hypertensive patients (mean diastolic ≥ 110 mmHg with or without medication) or patients with comorbidities. All patients, except those excluded (n=44), were open-block randomized to follow two treatment regimens ("traditional" or "current") and to receive or not receive telephone calls ("phone calls" and "no phone calls" groups, respectively).

RESULTS

Significantly fewer patients in the "phone calls" group discontinued treatment compared to those in the "no phone calls" group (4 vs. 30; p<0.0094). There was no difference in the percentage of patients with controlled blood pressure in the "phone calls" group and "no phone calls" group or in the "traditional" and "current" groups. The percentage of patients with controlled blood pressure (<140/90 mmHg) was increased at the end of the treatment (74%), reaching 80% in the "uncomplicated" group and 67% in the "complicated" group (p<0.000001).

CONCLUSION

Guidance to patients via active telephone calls is an efficient strategy for preventing the discontinuation of antihypertensive treatment.

Health-related quality of life and blood pressure control in hypertensive patients with and without complications

INTRODUCTION

The goal of antihypertensive treatment is to reduce blood pressure without interfering in health-related quality of life (HRQL) OBJECTIVE: This study aimed to assess the influence of hypertension control upon HRQL in hypertensive patients with and without complications.

MATERIALS AND METHODS

Seventy-seven hypertensive outpatients (71% women, 58% white, 60% with elementary school level education, average age 54 +/- 8 years) were observed during a 12-month special care program (phase 1: clinical visits every two months, donation of all antihypertensive medications, meetings with a multidisciplinary team, and active telephone calls) and three years of standard care (phase 2: clinical visits every four months, medication provided by the drugstore of the hospital with a two-hour wait and a possible lack of medication, no meetings with a multidisciplinary team or active telephone calls). The patient HRQL was assessed using Bulpitt and Fletcher's Specific Questionnaire, as well as the SF-36 scores. Hypertensive patients were divided into "with complications" (n=37, diastolic blood pressure great than 110 mm Hg for patients with or without treatment, with clinically evident target-organ or other associated illness) and "without complications" (n=40). The variables studied were quality of life, blood pressure control, hypertension gravity, and demographic characteristics.

RESULTS

In hypertensive patients with and without complications, both the systolic and diastolic blood pressure were significantly higher (p<0.05) in phase 2 of observation (143+/-18/84+/-11 and 144+/-21/93+/-11 mm Hg for patients with and without complications, respectively) relative to phase 1 (128+/-17/75+/-13 and 128+/-15/83+/-11 mm Hg). The proportion of patients with controlled blood pressure (defined as a blood pressure less than 140/90 mm Hg) decreased from 70% to 49% in the "with complications" group and from 78% to 50% in the "without complications" group during phase 2 of observation. The patients with complications showed a decrease in bodily pain, vitality, and mental health component summary scores in both phases. In phase 2, the patients without complications had significantly better HRQL scores compared to complicated patients using both the Bulpitt and Fletcher's Questionnaire and the SF-36 assessment of physical capacity, bodily pain, and vitality domain summary scores. With regards to hypertension control, there was a significant decrease from phase 1 to phase 2 in the vitality component summary scores and an increase in the emotional aspect component summary scores assessed by the SF-36, whereas Bulpitt and Fletcher's Questionnaire showed no differences in these scores.

CONCLUSION

Special care programs with multidisciplinary activities, individualized and personalized assistance, easy access to pharmacological treatment, frequent meetings, and active telephone calls for hypertensive patients significantly increase blood pressure control but do not interfere with the HRQL.

Low-dose estrogen therapy does not change postexercise hypotension, sympathetic nerve activity reduction, and vasodilation in healthy postmenopausal women

The aim of this study was to determine whether estrogen therapy enhances postexercise muscle sympathetic nerve activity (MSNA) decrease and vasodilation, resulting in a greater postexercise hypotension. Eighteen postmenopausal women received oral estrogen therapy (ET; n = 9, 1 mg/day) or placebo ( n = 9) for 6 mo. They then participated in one 45-min exercise session (cycle ergometer at 50% of oxygen uptake peak) and one 45-min control session (seated rest) in random order. Blood pressure (BP, oscillometry), heart rate (HR), MSNA (microneurography), forearm blood flow (FBF, plethysmography), and forearm vascular resistance (FVR) were measured 60 min later. FVR was calculated. Data were analyzed using a two-way ANOVA. Although postexercise physiological responses were unaltered, HR was significantly lower in the ET group than in the placebo group (59 ± 2 vs. 71 ± 2 beats/min, P < 0.01). In both groups, exercise produced significant decreases in systolic BP (145 ± 3 vs. 154 ± 3 mmHg, P = 0.01), diastolic BP (71 ± 3 vs. 75 ± 2 mmHg, P = 0.04), mean BP (89 ± 2 vs. 93 ± 2 mmHg, P = 0.02), MSNA (29 ± 2 vs. 35 ± 1 bursts/min, P < 0.01), and FVR (33 ± 4 vs. 55 ± 10 units, P = 0.01), whereas it increased FBF (2.7 ± 0.4 vs. 1.6 ± 0.2 ml·min−1·100 ml−1, P = 0.02) and did not change HR (64 ± 2 vs. 65 ± 2 beats/min, P = 0.3). Although ET did not change postexercise BP, HR, MSNA, FBF, or FVR responses, it reduced absolute HR values at baseline and after exercise.

Is the accuracy of blood pressure measuring devices underestimated at increasing blood pressure levels?

BACKGROUND

In validation studies reporting on the accuracy of blood pressure measuring devices (ambulatory and non-ambulatory systems), it is frequently stated that the accuracy of blood pressure devices seems to decrease at increasing blood pressure levels. This has been shown for several ambulatory devices in the past. Whether more recently validated devices are less accurate at increasing blood pressure levels is unknown, however.

OBJECTIVES

We therefore retrospectively searched the literature for studies performed between 1993 and 2003, reporting on the accuracy of blood pressure measuring devices over different blood pressure levels. When needed, additional information from the authors was requested.

METHODS

In total, 30 studies were selected. Of these, the studies reporting on the accuracy of 14 different ambulatory and nine different non-ambulatory devices were useful. For both ambulatory and non-ambulatory devices, accuracy appeared to decrease at increasing blood pressure levels. This was particularly shown for systolic blood pressure.

RESULTS

We speculate whether this finding is due to the oscillometric method of blood pressure measurement. Another explanation may exist, however. Blood pressure variability increases with higher blood pressure. Further, the British Hypertension Society protocol 1993 uses sequential measurements. This may be the reason that, owing to the increased blood pressure variability, the accuracy of most devices tends to decrease at higher blood pressure levels. Consequently, the accuracy of blood pressure measuring devices may be underestimated at higher blood pressure levels.

CONCLUSION

Currently used automated blood pressure measurement devices seem to be less accurate at increasing blood pressure levels. It is important to be aware of this phenomenon when treating hypertensive patients. The reported decrease in accuracy, however, may well be explained by the increasing blood pressure variability at increasing blood pressure and the use of sequential measurements. If this is the case, then the accuracy of these devices is perhaps underestimated.

How accurate are automated blood pressure monitors?

Increasingly, automated blood pressure devices are replacing mercury sphygmomanometers to monitor blood pressure in primary care settings. Practitioners have raised questions about the accuracy of these new devices, so a mini-review was undertaken to examine the evidence. A systematic search of the Medline database identified seven studies that were of sufficient quality. Eight devices were examined, all of which had passed validation procedures, achieving A or B grades according to current protocols. All were 'recommended for clinical use', despite the tendency of the devices to produce inaccurate measurements in high blood pressure ranges. The review demonstrates that 'accuracy' of the new devices does not equate to the accustomed accuracy of the mercury sphygmomanometer.

Blood pressure measurement in obese patients: comparison between upper arm and forearm measurements

BACKGROUND

It is well known that blood pressure measurement with a standard 12-13 cm wide cuff is erroneous for large arms.

OBJECTIVE

To compare arm blood pressure measurements with an appropriate cuff and forearm blood pressure measurements (BPM) with a standard cuff, and both measurements by the Photopletismography (Finapres) method.

METHODS

One hundred and twenty-nine obese patients were studied (body mass index=40+/-7 kg/m2). The patients had three arm BPM taken by an automatic oscillometric device using an appropriate cuff and three forearm BPM with a standard cuff in the sitting position after a five-minute rest. Data were analysed by the analysis of variance. The correction values were obtained by the linear regression test.

RESULTS

Systolic and diastolic arm BPM with an appropriate cuff were significantly lower (p<0.05) than forearm BPM with a standard cuff. The measurements obtained by Finapres were significantly lower (p<0.05) than those found for forearm systolic and diastolic blood pressures and upper arm diastolic blood pressure. The equation to correct BPM in forearm in obese patients with arm circumference between 32-44 cm was: systolic BPM=33.2+/-0.68 x systolic forearm BPM, and diastolic BPM=25.2+0.59 x forearm diastolic BPM.

CONCLUSION

This study showed that forearm blood pressure measurement overestimates the values of arm blood pressure measurement. In addition, it is possible to correct forearm BPM with an equation.