Rapid oscillometric blood pressure measurement compared to conventional oscillometric measurement.

BACKGROUND: There have been few reports studying the necessary interval between blood pressure measurements, after the initial rest period. METHODS: Blood pressure was measured in 50 patients using the conventional oscillometric technique (COT) and the rapid oscillometric technique (ROT). RESULTS: The difference between COT and ROT was -1.1 / -0.1 mmHg, which was not significantly different (p = 0.8 / 1.0) and the pulse difference was -0.8 beats per minute (p = 0.8). CONCLUSIONS: It is concluded that a 15-second interval between blood pressure readings is as accurate as a one-minute interval providing that these measurements are started after a 5-minute rest period.

Effect of regression of left ventricular hypertrophy from systemic hypertension on systolic function assessed by midwall shortening (HOT echocardiographic study).

Depressed midwall shortening has been shown to be an independent predictor of cardiovascular morbid events in hypertensive patients with left ventricular (LV) hypertrophy despite normal endocardial fractional shortening. The effects of LV mass changes in hypertensive patients on midwall shortening are unclear. To determine the impact of LV hypertrophy regression on LV systolic function assessed at the endocardium and the midwall level, 508 patients (58% men, 57% Caucasians, mean age 60 +/- 7 years) participating in the Hypertension Optimal Treatment study were prospectively studied by serial echocardiography at baseline, year 1, year 2, and at the end of the study. The Hypertension Optimal Treatment study was designed to challenge the existence of the J-curve phenomenon in hypertension. This study enrolled men and women between 50 and 80 years of age with mild to moderate hypertension. Patients were treated with a regimen based on felodipine with the addition of other antihypertensive drug classes as needed to reduce the diastolic blood pressure to a predefined target of < or =80, < or =85, or < or =90 mm Hg. From baseline to year 1, year 2, and end of the study, body mass index was unchanged (30.4, 30.1, 30.2, and 30.5 kg/m(2)); however, diastolic blood pressure was significantly reduced (99, 83, 80, and 80 mm Hg, p <0.0001), as was systolic blood pressure (161, 139, 137, and 134 mm Hg, p <0.0001) and LV mass index (117, 119, 107, and 106 g/m(2), p <0.0001). Over the same period of observation the endocardial fractional shortening did not change significantly (40%, 42%, 43%, and 44%); however, shortening at the midwall level showed improvement (20%, 21%, 22%, and 30%, p <0.001). In conclusion, midwall shortening is a more sensitive index of systolic function in subjects with pressure-overload hypertrophy, and it identifies high-risk patients who may benefit from a more aggressive antihypertensive program. The disparity between midwall and endocardial shortening suggests reduced myofibril function in patients with hypertension-induced hypertrophy.

Accuracy of aneroid sphygmomanometers in clinical usage: University of Michigan experience.

BACKGROUND: Aneroid manometers are frequently used to measure blood pressure. Aneroid manometers have moving parts that are subject to fatigue. The accuracy duration of the aneroid devices, like most digital devices, is unstudied. It has been accepted that if the aneroid device does not rest at '0' it is inaccurate, but how often is the device inaccurate when it does rest at '0'? METHODS: A Universal Biometer DPM-III measuring unit was used for all of the measurements at 10 University of Michigan Health System sites. A total of 136 aneroid manometers were tested. Two additional aneroid devices were not tested, as the needle did not start within '0'. Static pressure measurements were made at nine levels for all devices: 50, 80, 90, 100, 120, 150, 200 and 250mmHg. RESULTS: The average difference of the nine pressure settings of the whole group was 0.2+/-0.31 (95% confidence interval 0.1-0.2) mmHg. The largest number of devices that were not calibrated within +/-3mmHg was seen at the 150mmHg setting with six (4.4%) of the devices failing. If an accuracy standard of +/-2mmHg was used, the largest number of devices failed at 250mmHg (22 devices, 16.2%). The largest number of devices that were inaccurate was manufactured 6 years prior to testing and was from two sites. CONCLUSIONS: Aneroid devices were accurate. A yearly calibration programme should be performed and a +/-2mmHg standard should be used. Portable aneroid manometers may need to be more frequently calibrated due to the trauma associated with dropping.

Home blood pressure monitoring.

Hypertension is estimated to affect 43 to 56 million adults or 24% to 31% of the US population and is emerging as a major health problem in some countries in the Third World. Hypertension contributes to all the major atherosclerotic cardiovascular disease outcomes.

Measurement variation among 12 electronic home blood pressure monitors.

Although there are AAMI and BHS standards for accuracy of electronic home electronic blood pressure monitors (HBPM), patient composition differences and differences in manufacturer's algorithm for calculation of the systolic and diastolic measurement may result in measurement differences between monitors. The aim of this study was the measurement of differences among HBPM. Paired comparisons were performed between the Omron 712c electronic home monitor and each of 12 other HBPM (Sunbeam 7654, Sunbeam 7623, Omron 711, Omron 432c, A&D-UA767, Lumiscope 1085M, Omron 725CIC, Assure A30, Lumiscope 1083N, Omron 815, Omron 605, and Assure BD-W20), in addition to comparison to the auscultatory method by trained observers. Measurements were made in normotensive subjects in an ambulatory setting. The main outcome measures were systolic and diastolic blood pressure measurements. All of the HBPM, except for the Sunbeam 7654 and the Assure A30/ BD-W20 (wrist) models, demonstrated small differences of <4/4 mm Hg for systolic/diastolic measurements with pulse measurement differences of <3 beats/min. These differences were less than the differences previously reported for office BP auscultation of 6/5-10 mm Hg for systolic/diastolic measurements. The Omron 712c, passing previous AAMI and BHS standards, measured the systolic reading within 2 mm Hg of auscultatory mercury or aneroid measurement and under-measured the diastolic by 6-9 mm Hg. Differences in the patient composition studied could account for the difference. The wrist and finger manometers performed clinically similar to the Omron 712c, except for the Assure BD-W20, which overmeasured the diastolic by 7 mm Hg. It is concluded that the small differences among the various HBPM, which are less than those in clinical office auscultation, should encourage greater use of electronic manometers in the office and at home.

Determination of accuracies of 10 models of home blood pressure monitors using an oscillometric simulator.

BACKGROUND: Patients and doctors often use home blood pressure monitoring (HBPM) to assess the control of hypertension. Despite its popularity there has always been some uncertainty with regard to its accuracy, reliability, reproducibility, and comparability. Although there are pre-market HBPM standards of accuracy, there are no standards to assure accuracy of individual HBPM units after they have been brought home. OBJECTIVE: Determination of reliability, reproducibility, and comparability of 10 models of home blood pressure monitors. METHODS: We used a Biotek BP Pump as an oscillometric simulator of systolic and diastolic blood pressures to determine reliability, reproducibility, and comparability of 10 devices. RESULTS: All of the units tested, except the Pollonex BP1000, produced reproducible readings with the pooled SD of four blood pressure settings less than 3.10 mmHg both for systolic and for diastolic measurements. The oscillometric blood pressure pump method was found to be very reproducible, with pooled differences of less than 2 mmHg and SD of less than 0.5 mmHg for a repeated series of measurements using the same monitor. Different machines of the same model were also very comparable, with pooled differences of less than 3.6 mmHg and pooled SD less than 0.7 mmHg both for systolic and for diastolic readings. There were 11-14 mmHg differences between models for all of the simulated blood pressure readings except that a 27 mmHg difference was measured at the 200 mmHg systolic blood pressure level. These differences will not necessarily be the same for measurements with humans instead of oscillometric signal generation. A system for grading the accuracy of the tested HBPM that defines accuracy of HBPM as within +/-2 SD of the average of 85 measurements is described. CONCLUSION: All models of home blood pressure monitors tested, with the exceptions of the Pollonex BP1000, produced reproducible readings and different machines of the same model were comparable.

Comparison in systemic hypertension of left ventricular mass and geometry with systolic and diastolic function in patients <65 to > or = 65 years of age.

Previous studies have differed on the independent effect of age and gender to left ventricular (LV) mass. Data on ventricular remodeling in hypertensive patients > or = 65 years of age is lacking. Similarly, the systolic and diastolic interaction in older hypertensives is not well defined. In a prospective study, we examined the relation of LV mass, relative wall thickness, and systolic and diastolic interaction in 508 hypertensive patients between 50 and 80 years of age who were divided according to age (<65 and > or = 65 years) and gender. LV mass, geometric classification, systolic wall stress, and Doppler filling were obtained according to standard Doppler echocardiographic criteria. In men, most measurements were similarly distributed. However, women > or = 65 years of age had smaller LV systolic dimensions, thicker ventricular septums, higher endocardial and midwall fractional shortenings, and lower end-systolic wall stress. Although LV mass was higher in men, there was no age difference within the same sex. The most common LV geometric remodeling was increased relative wall thickness in the form of concentric hypertrophy or concentric remodeled. The predominant mitral flow pattern was "impaired relaxation"; however, older patients had even shorter E waves, taller A waves, and lower E/A ratios. Thus, patients > or = 65 years of age had an even higher prevalence of this pattern (men, 89% vs 73%, p <0.001, and women, 91% vs 77%, p <0.001). Delayed LV relaxation with preservation of systolic ejection indexes is an early abnormality in essential hypertension, which lasts an undetermined time with further progression as patients aged. As a result, hypertensive patients > or = 65 years of age had the most pronounced structural and functional changes, an observation particularly noted in women. In those > or = 65 years, data from the Doppler E wave and A wave do not distinguish the physiologic process of aging from the pathologic changes of pressure overload.

Impact of ethnicity on left ventricular mass and relative wall thickness in essential hypertension.

This study was designed to evaluate the impact of ethnicity on left ventricular (LV) mass, and relative wall thickness in 527 patients (57% men, mean age 60 +/- 7 years) with mild to moderate high blood pressure. There were 63% Caucasians, 21% African-Americans, and 16% Hispanics. LV mass was indexed according to body surface area, height, and height to the allometric power of 2.7. Relative wall thickness included the 4 widely recognized patterns: normal, concentric remodeling, eccentric hypertrophy, and concentric hypertrophy. LV mass indexed to body surface area was similar among all 3 ethnic groups (Caucasians 117.1 g/m2, African-Americans 119.2 g/m2, Hispanics 122.7 g/m2); however, when indexed to height and height to the power of 2.7, Hispanics had slightly larger masses than the other 2 groups (Hispanics 168.1 and 73.3 g/m2.7 vs Caucasians 159.8 and 64.4 g/m2.7 [p = NS and p < 0.005]; and vs African-Americans 164.8 and 69.2 g/m2.7 [p = NS for both]). Using body surface area, the concentric remodeling was the predominant form of cardiac adaptation in Caucasians (36%) and African-Americans (42%), whereas the concentric hypertrophy pattern was 38% in Hispanics. Using indexing for both height and height to the power of 2.7, the concentric hypertrophy pattern predominated in all 3 ethnic groups (Caucasians 48% and 51%; African-Americans 68% and 66%; Hispanics 59% and 65%). In conclusion, because of the independent impact of weight on high blood pressure, LV mass adjusted to height or to height at the power of 2.7 should be reported in population studies. The concentric hypertrophy pattern--classic LV response to pressure overload conditions--is better represented when LV mass is indexed to height or to height to the allometric power of 2.7 than to body surface area.

Role of left ventricular hypertrophy in diastolic dysfunction in aged hypertensive patients.

OBJECTIVE: To evaluate the influence of left ventricular hypertrophy (LVH) on the diastolic dysfunction in older hypertensive patients. METHODS: In total 665 patients (58% men, 61% White, aged 55-80 years) with mild-to-moderate essential hypertension underwent Doppler echocardiography. Data included left ventricular dimensions, left ventricular mass index, body mass index, E- and A-wave mitral flow velocities, E:A ratio, deceleration time > 150 ms), impaired relaxation (E:A ratio < 1.0, prolonged deceleration time according to age), and restrictive physiology (E:A ratio > 2.1, deceleration time < 150 ms)]. Data were distributed according to age (50-59, 60-69, and 70-80 years). RESULTS: The overall prevalence of sex-adjusted LVH in this study was 65%. When we compared hypertensive patients with and without LVH, the E- and A-wave velocities, E:A ratio, and deceleration time were similar. Moreover, the prevalences of normal, impaired relaxation, and restrictive physiology patterns among patients with and without LVH did not differ significantly (20, 79.5, and 0.5 versus 24, 75.5, and 0.5%). When the mitral flow patterns were adjusted according to age, the impaired relaxation pattern increased further with age (to 73% during the fifth decade, 83% during the sixth decade, and 88% during the seventh decade). CONCLUSIONS: LVH is not an independent factor associated with abnormal flow patterns in hypertensive patients aged over 50 years with normal systolic contractility. The impaired relaxation is the predominant pattern of diastolic dysfunction in older hypertensive patients and increases further with aging.

Comparison of left ventricular mass and geometric remodeling in treated and untreated men and women >50 years of age with systemic hypertension.

To investigate the effects of left ventricular (LV) mass and geometry in hypertensive patients >50 years of age, 540 men and women were divided into controlled, uncontrolled, and untreated groups. The high prevalence of concentric LV hypertrophy in postmenopausal women, despite medical therapy, emerged as a potentially important and underrecognized factor of their cardiovascular risk.

Disparity between diastolic mitral flow characteristics and left ventricular mass in essential hypertension.

Because left ventricular (LV) hypertrophy and aging have been associated with abnormal LV relaxation, this study evaluated the impact of LV mass on the filling patterns derived by Doppler in a large population aged > or =50 years. Results suggest that in essential hypertension the intrinsic myocardial composition is more important than cardiac hypertrophy in determining LV diastolic properties. This apparent discrepancy between LV mass and diastolic filling patterns highlights the difficulty in establishing the diagnosis of diastolic dysfunction in elderly hypertensives.

Sodium concentration of water from softeners.

OBJECTIVES: To determine whether water is safe for consumption after it has passed through a water softener and whether there are any health and environmental implications of cationic water softeners. METHODS: Sodium concentration was measured in 59 water samples that had passed through a water softener and was compared with the sodium concentration of 5 samples from 4 different local municipal sources. RESULTS: The mean +/- SD sodium concentration of softened well water was 278 +/- 186 mg/L (range, 46-1219 mg/L). There were 10 (17%) households with sodium levels greater than 400 mg/L. The mean +/- SD sodium concentration of municipal, nonsoftened water was 110 +/- 98 mg/L (range, 0-253 mg/L). CONCLUSIONS: Softened well water in our area on average contained a 2.5-times-higher concentration of sodium than local municipal water, comparable with previous reports. It is unlikely that the increased sodium from softened water would have any health risks for most people. This may not be true for people on severely sodium-restricted diets.

Cost effectiveness of 24-hour ambulatory blood pressure monitoring in evaluation and treatment of essential hypertension.

We wanted to determine if use of ambulatory blood pressure monitoring (ABPM) was cost effective, preventing unnecessary drug therapy in patients misdiagnosed as having essential hypertension, with elevated office blood pressures and normal ambulatory blood pressure. To address this issue we surveyed costs to the patient for antihypertensive drug therapy in 1990 of five local pharmacies in southeastern Michigan. Patients studied (n = 192) were seen in a private, general internal medicine practice in rural southeastern Michigan and received ABPM to assess the presence of hypertension and the adequacy of blood pressure treatment. We ascertained the average, minimal, and maximal drug cost to the patient per unit dose at the local pharmacies. The average yearly cost for patients on antihypertensive medications at pharmacies in southwestern Michigan was $578.40, with figures varying from $94.90 to $4361.75. Although there is no standard reimbursement amount for ABPM, at $188 per monitoring, the cost of monitoring this entire group of patients would offset exactly the cost of medication for the group of patients found to have only office hypertension. As such, third-party insurance carriers should consider reimbursement for ABPM in hypertension to decrease pharmaceutical cost and its attendant potential side effects. In conclusion, our study results suggest that ABPM is cost effective in an outpatient setting in preventing unwarranted drug therapy and the inappropriate diagnosis of hypertension.

Ambulatory blood pressure monitoring in a nonacademic setting. Effects of age and sex.

Twenty-four-hour ambulatory blood pressure measurements (ABPM) are likely to eliminate the stress of visits and observer bias in office blood pressure (BP) recordings, allow consideration of the circadian variability in BP, and correlate well with target organ damage. To define the prevalence of "white coat" hypertension in a rural community to a nonacademic setting, and to assess age and sex related differences, we studied 131 patients who had more than two prior office diastolic BP measurements greater than 90 mm Hg and less than 115 mm Hg. Blood pressure was measured every 10 to 60 min for 24 h using the SpaceLabs 90207 device. Office BP readings were higher than ABPM in the group as a whole, in individual age groups, and in both sexes. The differences were more pronounced at night. Average differences between office and ambulatory BP ranged between 14.4 +/- 1.7/2.9 +/- 2.0 (ABPM at 10:00), and 33.8 +/- 2.3/22.8 +/- 1.5 mm Hg (systolic/diastolic +/- SE) (ABPM at 01:00). The nighttime drop in systolic BP was not apparent in subjects more than 65 years old. Women had a proportionately higher mean office BP than men (115.0 +/- 0.9 office v 110.2 +/- 1.3 mm Hg ABPM in women and 112.3 +/- 0.9 v 104.3 +/- 1.1 mm Hg in men) (P = .013), and the elderly did not display the relationship between ambulatory and office mean BP seen in younger subjects (r = 0.15, P = .30 v r = 0.36, P = .0004, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)