Influence of the hospital environment and presence of the physician on the white-coat effect.

OBJECTIVE: To determine the separate contribution of the physician and the hospital environment to differences between home (HBP) and office BP (OBP). METHODS: For 3 consecutive days, 65 hypertensive patients measured their HBP. OBP was determined with the same device by the physician. A higher OBP than HBP was regarded as white-coat effect (WCE), whereas lower OBP than HBP was regarded masked effect. OBP was measured automatically before, during and after the presence of the physician. The physician effect was the BP rise caused by the entrance of physician. The WCE minus the physician effect was regarded the hospital's contribution to the BP differences (hospital effect). We assessed the magnitudes of the hospital effect and the physician effect in determining the WCE. Furthermore, we assessed the correlation of these BP phenomena with each other, and with clinical variables. RESULTS: The WCE consisted of 4.6/-1.7 ±â€Š9.9/10.9 mmHg hospital effect and of 4.4/3.4 ±â€Š6.6/3.3 mmHg PE. The masked effect consisted of a substantially larger hospital effect (19.6/9.4 ±â€Š12.7/9.5 mmHg) than physician effect (4.6/3.0 ±â€Š6.4/3.9 mmHg). Physician effect did not correlate with systolic or diastolic WCE or masked effect (r = -0.05 to 0.08, P > 0.39). In regression analysis, age, baseline mean arterial pressure and BMI were not significantly associated with WCE (all P values >0.4). CONCLUSION: BP differences between home and office can largely be attributed to the hospital environment rather than to the entrance of the physician. The physician-related BP effect is not related to differences of HBP and OBP.

Should blood pressure be measured with the cuff on a bare arm?

OBJECTIVE: To establish whether the results of blood pressure (BP) measurements are affected by wearing clothing underneath the BP cuff during measurement. METHODS: Normotensive and hypertensive patients (n=133; 65 men) of an outpatient clinic participated in this study. BP was measured according to a rigorous protocol with a validated oscillometric device under three conditions: with one layer of own clothing (OC) underneath the cuff, with one layer of standardized clothing (SC) underneath the cuff, and with the cuff on a bare arm (BA), in a randomized order. Patients were seated on a chair with their right arm on the table and their feet flat on the floor during BP measurement. RESULTS: The mean BP values (±SEM) measured during BA, OC, and SC were, respectively, 132.8±1.3, 132.3±1.4, and 133.2±1.4 mmHg for systolic blood pressure (SBP), 78.3±0.9, 78.3±0.9, and 78.5±0.9 mmHg for diastolic blood pressure (DBP), and 90.3±1.0, 90.0±1.0, and 91.5±1.0 mmHg for mean arterial blood pressure (MAP). The differences in SBP, DBP, and MAP between BA, OC, and SC measurements were not statistically significant, but there was considerable intraindividual variation in SBP deviations of more than 5 mmHg between BA versus OC and SC. There was no significant order effect of the three conditions. The absence of differences between BA, OC, and SC was not determined by age, sex, BMI, and arm circumference. CONCLUSION: We could not find differences in MAP, SBP, and DBP between the bare and clothed arms, but intraindividual variation of SBP between the three conditions is not negligible. Despite this caveat, these data suggest that in an outpatient clinic, BP can be measured reliably with one layer of clothing underneath the cuff. This is timesaving and more comfortable for patients.

Does wave reflection explain the increase in blood pressure during leg crossing?

OBJECTIVE: To assess the effect of crossing legs at the knee level on wave reflection, as measured by the augmentation index. METHODS: Forty-two participants crossed their legs at the knee level (popliteal fossa over the suprapatellar bursa) in the sitting position for 12 min. One trained investigator performed the measurements before, during, and after leg crossing. We used the SphygmoCor to measure the augmentation index at the radial artery and an oscillometric device to measure blood pressure (BP) at the upper arm. We calculated the differences between the uncrossed and the crossed position for the augmentation index normalized for heart rate, peripheral BP, and central BP. RESULTS: Both peripheral systolic BP 2.5 ± 6.5 (mean ± SD) mmHg (0.5-4.6) (95% confidence interval) and peripheral diastolic BP 1.7 ± 3.8 mmHg (0.5-2.9) increased during leg crossing compared with the uncrossed position. In addition, central systolic BP 2.8 ± 5.8 (0.9-4.6) and central diastolic BP 1.8 ± 3.9 (0.5-3.0) increased, whereas no significant change in the augmentation index was observed. CONCLUSION: Our results indicate that the increase in BP during leg crossing cannot be explained by wave reflection. We found no change in the augmentation index during leg crossing at the knee level. Central BP and peripheral BP are equally influenced by leg crossing.

Exaggerated postural blood pressure rise is related to a favorable outcome in patients with acute ischemic stroke.

BACKGROUND AND PURPOSE: The effects of early upright positioning in the acute phase of ischemic stroke on both blood pressure and functional outcome have not been previously examined. METHODS: Prospective investigation of mean arterial pressure, heart rate, and peripheral oxygen saturation in the supine, sitting, and (if achievable) active standing position 1, 2, and 3 days after an acute stroke was performed. Also investigated was the presence of a significant postural blood pressure rise and fall using orthostatic definitions and the relation to functional outcome after 3 months. RESULTS: One hundred sixty-seven patients were included (mean age, 68.5±15.2 years; median National Institutes of Health Stroke Scale, 7). Approximately 60% of the patients were able to stand. On average the mean arterial pressure increased when patients moved from the supine to sitting (Day 1: Δ 3.9 mm Hg; P<0.001) and from sitting to an active standing position (Day 1: Δ 4.6 mm Hg; P<0.001). Changes were most pronounced within the first 24 hours after a stroke. Blood pressure decreased significantly (fall) on standing in 13% of patients and increased significantly (rise) in 20% of the patients. The latter was independently associated with a favorable outcome (P=0.003). Moving to the standing position was accompanied by an increase of heart rate. No difference in oxygen saturation was observed in the various positions over the period of investigation. CONCLUSIONS: We found that a significant blood pressure rise during early upright positioning in patients with acute stroke was independently associated with a favorable outcome. No contraindication to early mobilization was found in this study.

Variations of blood pressure in stroke unit patients may result from alternating body positions.

BACKGROUND: Blood pressure (BP) is one of the major vital parameters monitored in the stroke unit. The accuracy of indirect BP measurement is strongly influenced by the position of both patient and arm during the measurement. Acute stroke patients are often nursed in lateral decubitus positions. The effect of these alternating body positions in relation to affected body side on the outcome and reliability of BP readings in acute stroke patients is unknown. METHODS: An automatic oscillometric BP device was used. BP was measured in both arms in the (back) supine and both lateral decubitus positions. RESULTS: In total, 54 consecutive acute stroke patients were included. Thirty-five patients had right-sided deficits and 19 patients had left-sided deficits. Supine BP readings were similar in the right and left arms regardless of side of deficit. Measurements of BP in the lateral decubitus positions resulted in significantly lower BP readings in the uppermost arm (around 12 mm Hg in both arms) and significantly higher readings in the right lowermost arm (around 6 mm Hg) compared to the supine position. This effect seemed less pronounced when the left lowermost arm was measured. There was no relation between change of BP readings in various lateral positions and side of stroke. CONCLUSIONS: Alternating lateral decubitus positions according to nursing standards in acute stroke patients lead to a mean 18 mm Hg BP fluctuation. This may largely be explained by hydrostatic pressure effects, partly by anatomic factors in the left lowermost arm, but not by the side of stroke.

Thirty-minute compared to standardised office blood pressure measurement in general practice.

BACKGROUND: Although blood pressure measurement is one of the most frequently performed measurements in clinical practice, there are concerns about its reliability. Serial, automated oscillometric blood pressure measurement has the potential to reduce measurement bias and white-coat effect'. AIM: To study agreement of 30-minute office blood pressure measurement (OBPM) with standardised OBPM, and to compare repeatability. DESIGN AND SETTING: Method comparison study in two general practices in The Netherlands. METHOD: Thirty-minute and standardised OBPM was carried out with the same, validated device in 83 adult patients, and the procedure was repeated after 2 weeks. During 30-minute OBPM, blood pressure was measured automatically every 3 minutes, with the patient in a sitting position, alone in a quiet room. Agreement between 30-minute and standardised OBPM was assessed by Bland-Altman analysis. Repeatability of the blood pressure measurement methods after 2 weeks was expressed as the mean difference in combination with the standard deviation of difference (SDD). RESULTS: Mean 30-minute OBPM readings were 7.6/2.5 mmHg (95% confidence interval [CI] = 6.1 to 9.1/1.5 to 3.4 mmHg) lower than standardised OBPM readings. The mean difference and SDD between repeated 30-minute OBPMs (mean difference = 3/1 mmHg, 95% CI = 1 to 5/0 to 2 mmHg; SDD 9.5/5.3 mmHg) were lower than those of standardised OBPMs (mean difference = 6/2 mmHg, 95% CI = 4 to 8/1 to 4 mmHg; SDD 10.9/6.3 mmHg). CONCLUSION: Thirty-minute OBPM resulted in lower readings than standardised OBPM and had a better repeatability. These results suggest that 30-minute OBPM better reflects the patient's true blood pressure than standardised OBPM does.

Blood pressure measurement method and inter-arm differences: a meta-analysis.

BACKGROUND: Screening for inter-arm difference (IAD) of blood pressure (BP) at each first visit is recommended by numerous guidelines whereas it is unclear whether the method by which IAD is measured has significant influence on the IAD value. METHODS: A systematic review is made of the studies reporting on double-arm measurements and the association of IAD with procedure characteristics (Medline/PubMed, Embase, and Cochrane Library). RESULTS: The mean absolute IAD was 5.4 ± 1.7 and 3.6 ± 1.2 mm Hg for systolic and diastolic BP, respectively. Of all subjects 14% had a systolic IAD ≥10 mm Hg, 4% a systolic IAD ≥20 mm Hg, and 7% a diastolic IAD ≥10 mm Hg. The relative risk (RR) of obtaining a systolic IAD ≥10 and 20 mm Hg and a diastolic IAD ≥10 mm Hg is higher when measuring sequentially instead of simultaneously (2.2 (95% CI: 1.4-3.6), P < 0.01; 4.8 (95% CI: 1.1-21.9), P < 0.05 and 2.5 (95% CI: 1.0-6.3) P < 0.05, respectively), when using a manual instead of an automated device (2.1 (95% CI: 1.1-3.9), P < 0.05; 4.4 (95% CI: 1.8-10.8), P < 0.01 and 3.7 (95% CI: 1.6-8.6), P < 0.01, respectively) and when performing only one BP measurement instead of multiple (2.0 (95% CI: 1.1-3.8), P < 0.05; 4.3 (95% CI: 1.6-11.4), P < 0.01 and 4.4 (95% CI: 1.7-11.4), P < 0.01, respectively). CONCLUSION: Screening for IAD of BP is important but the measurement methodology has a major influence on IAD results. To prevent overestimation and observer bias IAD should be assessed simultaneously at both arms, with one or two automatic devices and multiple readings should be taken.

Telecare is a valuable tool for hypertension management, a systematic review and meta-analysis.

There is an increasing interest for using telecare(TC) in the management of hypertension. A systematic review to the use of blood pressure (BP) measurement in TC has been performed (Medline/PubMed, Embase, and Cochrane Library), selecting randomized clinical trials that compared TC with usual care (UC) for hypertension management (treatment and/or coaching). Nine randomized clinical trials were selected (n=2501, 61.4±0.6 years, 42±2.7% males). Overall there was a significant larger decrease in the TC group than in the UC group for systolic (5.2±1.5 mmHg; P<0.001) and diastolic BP (2.1±0.8 mmHg; P<0.01). When studies were separated for antihypertensive treatment modification during the study (yes or no), systolic BP decrease difference between the TC and UC groups (ΔTC-ΔUC) tended to be significantly lower (5.1±2.9 mmHg lower) with treatment modification compared with nontreatment modification in which the ΔTC-ΔUC was 8.6±2.4 mmHg, P=0.07. TC led to a greater decrease in systolic and diastolic BP than UC. The differences between TC and UC for systolic BP tend to become larger when no treatment modification is applied. TC seems a valuable tool for hypertension management.

A novel approach to office blood pressure measurement: 30-minute office blood pressure vs daytime ambulatory blood pressure.

PURPOSE: Current office blood pressure measurement (OBPM) is often not executed according to guidelines and cannot prevent the white-coat effect. Serial, automated, oscillometric OBPM has the potential to overcome both these problems. We therefore developed a 30-minute OBPM method that we compared with daytime ambulatory blood pressure. METHODS: Patients referred to a primary care diagnostic center for 24-hour ambulatory blood pressure monitoring (ABPM) had their blood pressure measured using the same validated ABPM device for both ABPM and 30-minute OBPMs. During 30-minute OBPM, blood pressure was measured automatically every 5 minutes with the patient sitting alone in a quiet room. The mean 30-minute OBPM (based on t = 5 to t = 30 minutes) was compared with mean daytime ABPM using paired t tests and the approach described by Bland and Altman on method comparison. RESULTS: We analyzed data from 84 patients (mean age 57 years; 61% female). Systolic and diastolic blood pressures differed from 0 to 2 mm Hg (95% confidence interval, -2 to 2 mm Hg and from 0 to 3 mm Hg) between mean 30-minute OBPM and daytime ABPM, respectively. The limits of agreement were between -19 and 19 mm Hg for systolic and -10 and 13 mm Hg for diastolic blood pressures. Both 30-minute OBPM and daytime ABPM classified normotension, white-coat hypertension, masked hypertension, and sustained hypertension equally. CONCLUSIONS: The 30-minute OBPM appears to agree well with daytime ABPM and has the potential to detect white-coat and masked hypertension. This finding makes 30-minute OBPM a promising new method to determine blood pressure during diagnosis and follow-up of patients with elevated blood pressures.

Sphygmomanometric and ambulatory blood pressures as forerunners of carotid and femoral intima-media thickness.

OBJECTIVE: Studies directly comparing the associations of intima-media thickness with blood pressure (BP) on manual sphygmomanometric blood pressure measurement (SBPM) and 24-h ambulatory blood pressure measurement (ABPM) are scarce and have a cross-sectional design. METHODS: At baseline, we measured systolic and diastolic blood pressures, pulse pressure, and mean arterial pressure in 532 randomly recruited patients (women, 48.3%; mean age, 38.9 years) by SBPM and ABPM. SBPM was the average of five consecutive readings obtained by trained observers at the patients' homes. We measured carotid intima-media thickness (CIMT) and femoral intima-media thickness (FIMT) by a wall-tracking ultrasound system, 26 months (median) after BP measurement (interquartile range, 21-29 months). We adjusted all analyses for observer, sex, age, BMI, smoking, and total/high-density lipoprotein-cholesterol ratio. RESULTS: The multivariable-adjusted associations of CIMT and FIMT with all BP components on SBPM were not significant (P >or= 0.12). In multivariable-adjusted models, CIMT increased with 24-h systolic blood pressure (effect size per SD increase, +0.131 mm; P = 0.003) and 24-h pulse pressure (+0.139 mm; P = 0.001), whereas FIMT increased with 24-h diastolic blood pressure (+0.091 mm; P = 0.03) and 24-h mean arterial pressure (+0.090 mm; P = 0.04). Models including the ambulatory blood pressure components additionally adjusted for SBPM and more covariables than those listed above were confirmatory. CONCLUSION: In a general population, BP on ABPM predicts CIMT and FIMT over and beyond highly standardized SBPM. At the elastic carotid artery, CIMT increased predominantly with the pulsatile component of BP, whereas at the muscular femoral artery, FIMT increased with the steady component of BP.

Determinants of the ambulatory arterial stiffness index in 7604 subjects from 6 populations.

The ambulatory arterial stiffness index (AASI) is derived from 24-hour ambulatory blood pressure recordings. We investigated whether the goodness-of-fit of the AASI regression line in individual subjects (r(2)) impacts on the association of AASI with established determinants of the relation between diastolic and systolic blood pressures. We constructed the International Database on the Ambulatory Blood Pressure in Relation to Cardiovascular Outcomes (7604 participants from 6 countries). AASI was unity minus the regression slope of diastolic on systolic blood pressure in individual 24-hour ambulatory recordings. AASI correlated positively with age and 24-hour mean arterial pressure and negatively with body height and 24-hour heart rate. The single correlation coefficients and the mutually adjusted partial regression coefficients of AASI with age, height, 24-hour mean pressure, and 24-hour heart rate increased from the lowest to the highest quartile of r(2). These findings were consistent in dippers and nondippers (night:day ratio of systolic pressure >or=0.90), women and men, and in Europeans, Asians, and South Americans. The cumulative z score for the association of AASI with these determinants of the relation between diastolic and systolic blood pressures increased curvilinearly with r(2), with most of the improvement in the association occurring above the 20th percentile of r(2) (0.36). In conclusion, a better fit of the AASI regression line enhances the statistical power of analyses involving AASI as marker of arterial stiffness. An r(2) value of 0.36 might be a threshold in sensitivity analyses to improve the stratification of cardiovascular risk.

Thirty years of research on diagnostic and therapeutic thresholds for the self-measured blood pressure at home.

OBJECTIVE: The goal of this review study is to summarize 30 years of research on cut-off limits for the self-measured blood pressure. METHODS: We reviewed two meta-analyses, several prospective outcome studies in populations and hypertensive patients, studies in pregnant women, three clinical trials and the thresholds proposed in earlier and current hypertension guidelines. RESULTS: In line with existing guidelines, prospective studies support that levels of the self-measured blood pressure at home of greater than or equal to 135 mmHg systolic or greater than or equal to 85 mmHg diastolic indicate hypertension. Circumstantial data suggest that levels of the self-measured blood pressure below 120/80 and 130/85 mmHg are optimal and normal, respectively. Therapeutic targets of the self-measured blood pressure to be attained on antihypertensive drug treatment are currently unknown, but should logically be lower (<135/85 mmHg) than those used to diagnose hypertension. Currently, there is no proof that therapeutic thresholds for the home blood pressure should be lower in high-risk compared with normal-risk patients. A large body of evidence, however, demonstrated that each millimetre of mercury of blood pressure lowering counts in the prevention of cardiovascular complications and that in high-risk patients even small decreases in blood pressure result in large absolute benefit. CONCLUSION: The thresholds to diagnose hypertension from self-measured blood pressure readings at home remain unaltered since the 2000 consensus conference, but are currently supported by outcome data. Further studies need to establish what values of the self-measured blood pressure are optimal and normal in terms of cardiovascular outcome.

Reproducibility of the ambulatory arterial stiffness index in hypertensive patients.

BACKGROUND: We studied the repeatability of the ambulatory arterial stiffness index (AASI), which can be computed from 24-h blood pressure (BP) recordings as unity minus the regression slope of diastolic on systolic BP. METHODS: One hundred and fifty-two hypertensive outpatients recruited in Nijmegen (mean age = 46.2 years; 76.3% with systolic and diastolic hypertension) and 145 patients enrolled in the Systolic Hypertension in Europe (Syst-Eur) trial (71.0 years) underwent 24-h BP monitoring at a median interval of 8 and 31 days, respectively. We used the repeatability coefficient, which is twice the SD of the within-participant differences between repeat recordings, and expressed it as a percentage of four times the SD of the mean of the paired measurements. RESULTS: Mean AASI (crude or derived by time-weighted or robust regression) and 24-h pulse pressure (PP) were similar on repeat recordings in both cohorts. In Nijmegen patients, repeatability coefficients of AASI and PP were approximately 50%. In Syst-Eur trial patients, repeatability coefficient was approximately 60% for AASI and approximately 40% for PP. For comparison, repeatability coefficients for 24-h systolic and diastolic BP were approximately 30%. Differences in AASI between paired recordings were correlated with differences in the goodness of fit (r2) of the AASI regression line as well as with differences in the night-to-day BP ratio. However, in sensitivity analyses stratified for type of hypertension, r2, or dipping status, repeatability coefficients for AASI did not widely depart from 50 to 60% range. CONCLUSION: Estimates of mean AASI were not different between repeat recordings, and repeatability coefficients were within the 50-60% range.