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PubMedDate not supplied

[Blood pressure in young men with a family history of primary hypertension--traditional and 24-hour blood pressure measurements].

Blood pressure was measured in two groups of young males-group S-55 men with positive family history of essential hypertension (EH) and group K-11 men with negative family history of EH (mean age 24.5 +/- 3.3 and 23.5 +/- 4.7 years). Two methods of blood pressure measurement--traditional blood pressure measurement (method A) and automatic ambulatory indirect blood pressure monitoring (method B) were used. Blood pressure was higher in group S than in group K-method A 140 +/- 14/86 +/- 10 vs 122 +/- 10/73 +/- 8 mm Hg; method B: 132 +/- 11/78 +/- 10 vs 123 +/- 8/72 +/- 7 mm Hg. Contrary to group K, in group S discrepancies in the frequency of diagnosis of systolic or diastolic hypertension were found between the two methods of blood pressure measurement. These results indicate that in young males the traditional method of blood pressure measurement may provide a false positive diagnosis of hypertension, but both methods of blood pressure measurement used in this work were effective in the diagnosis of normotension. As a population the young males with positive family history of EH have higher blood pressure then young males with negative family history of EH.

Adult↗

PubMed1995

Relationship between blood pressure during haemodialysis and ambulatory blood pressure in between dialyses.

BACKGROUND: Ambulatory blood pressure measurements in haemodialysis patients are relevant in view of the high cardiovascular morbidity and mortality in chronic haemodialysis patients. METHODS: Twelve normotensive patients were studied from the beginning of one dialysis until the end of the next (mean 64 h, SD 19 h) using a Spacelabs oscillometric blood-pressure recorder. RESULTS: A circadian blood pressure rhythm was present in six of the 12 patients. In seven patients the lowest pressure recorded (including the dialysis sessions) occurred 5-6 h after dialysis (late post-dialysis dip). Blood pressure did not increase sharply in the hours before dialysis although it increased slightly in the interdialytic interval as a whole, at a mean rate of 5.6 mmHg per 24 h (SD 4.1, P < 0.001). We could not find a blood pressure measurement during dialysis (or combination of measurements) which reliably reflects interdialytic blood pressure: the 95% confidence intervals were 25 mmHg or higher. CONCLUSION: Ambulatory blood pressure measurements are needed for adequate monitoring of the control of blood pressure in haemodialysis patients.

Adult↗

PubMed1996

[Comparison between ambulatory 24-hour blood pressure measurement and occasional blood pressure measurement in hemodialysis patients with left heart hypertrophy].

Since 24-hour blood pressure monitoring seems to be superior to occasional blood pressure measurement as far as risk stratification is concerned, we compared the two methods in patients with secondary hypertension and left ventricular hypertrophy. In 26 haemodialysis patients (12 male, mean age 54 +/- 13 years), the mean occasional blood pressure values during haemodialysis were 147 +/- 18/82 +/- 9 mmHg, the mean 24-hour blood pressure values were 145 +/- 21/ 85 +/- 13 mmHg, during the day 145 +/- 23/86 +/- 13, during the night 143 +/- 25/81 +/- 13 mmHg. The nocturnal reduction of mean blood pressure was -3.6 +/- 7%. Both methods of blood pressure monitoring showed a significant correlation with the relevant echocardiographic parameters of left ventricular hypertrophy, cardiac mass and interventricular septum diameter. Patients with and without a nocturnal reduction in blood pressure could not be differentiated by the mean occasional blood pressure values. Therefore, 24 h ambulatory blood pressure monitoring seems warranted in this high risk group, especially to monitor antihypertensive drug therapy.

Adult↗

PubMed1996

[Blood pressure assessment in normoreactive and hyperreactive patients. A comparative study between casual and ambulatory blood pressure monitoring].

PURPOSE: To evaluate the levels of blood pressure when measured by casual and ambulatory blood pressure monitoring. METHODS: We studied 16 sedentary and normotensive subjects (mean 43 +/- 3 years old) showing an exaggerated blood pressure response (SBP > 220 mmHg) during a cycloergometric test, hyperreactive group (HG). This group was compared to 15 others with SBP < or = 220 mmHg during exercise, normoreactive group (NG). Casual blood pressure was obtained by the conventional method and the ambulatory blood pressure monitoring (ABPM) was obtained with SpaceLabs 90207 monitor. This procedure (test 1) was repeated after four months (test 2). RESULTS: Both groups showed statistically higher levels of blood pressure when measured by ABPM device, compared to casual measurements. Systolic blood pressure was significantly higher in HG in casual measurement, in test 1 but not in test 2. Diastolic blood pressure was significantly higher in HG only through the ABPM device. The ambulatory blood pressure average values for two or 24 hours was similar in both groups. No significant differences were observed in left ventricular morphology at the echocardiogram. CONCLUSION: These findings indicate that hyperreactive subjects have an exaggerated stress-induced cardiovascular response during the installation of the device.

Adult↗

PubMed1998

Joint fluid hydrostatic pressures that empty synovial capillaries of red cells have a wide range and correlate with pressures emptying arterioles.

OBJECTIVE: To study if, as predicted by calculations based on 3 Starling pressures, the fourth one, capillary pressure, may increase enough to contribute to joint swelling. METHODS: At magnifying arthroscopy, red cells mostly flow separated from each other in capillaries and precapillary vessels (arterioles). These are emptied of erythrocytes at intraarticular injection of saline to "tamponade" pressures. Patients sent for arthroscopy of the knee joint for mechanical or other lesions, or "internal derangement" (n = 30) or osteoarthritis (n = 26) were studied. RESULTS: The range of capillary (including postcapillary venular) tamponade pressure was 9-70 mm Hg. It correlated (r = 0.536, p < 0.001) with arteriolar tamponade pressure (range 20-100 mm Hg). CONCLUSION: If intravascular hydrostatic pressure is the main determinant of tamponade pressure, then increase of capillary pressure, possibly due to arteriolar dilatation induced precapillary pressure increase, may be a key mechanism in enhanced formation of synovial fluid.

Adolescent↗

PubMed1995

Failure of the community-based Vita-Stat automated blood pressure device to accurately measure blood pressure.

OBJECTIVE: To evaluate the Vita-Stat automated blood pressure computer (a patient-operated blood pressure measuring device available in the community) to determine its value as an instrument to monitor blood pressure in the ambulatory patient. DESIGN: Comparative study using the Vita-Stat vs a gold standard, the mercury sphygmomanometer. SETTING: Three local grocery stores. PARTICIPANTS: Sixty-three passersby who agreed to answer questions and to sit for several measurements of blood pressure. INTERVENTIONS: Simultaneous measurement of blood pressure with each subject wearing a Vita-Stat cuff on the left arm and a mercury sphygmomanometer cuff on the right arm. Two pressures were measured sequentially in the same manner. MAIN OUTCOME MEASURES: The reproducibility, accuracy, sensitivity, and specificity of the Vita-Stat computer compared with the gold standard. RESULTS: In sequential measurements, the Vita-Stat readings of both systolic and diastolic blood pressure correlated less well with each other than did the mercury readings (intramachine differences). The Vita-Stat readings also correlated poorly with the mercury readings of systolic and diastolic blood pressure (intermachine differences). The variability in readings recorded by the Vita-Stat were striking, with differences of up to 60 mm Hg from the mercury readings. More than half (63.2%) of the subjects had Vita-Stat readings that were more than 5 mm Hg different from the mercury readings. Vita-Stat systolic readings were usually lower than mercury readings and also varied by as much as 60 mm Hg below in one patient to 58 mm Hg above the mercury reading in another. The sensitivity of the Vita-Stat in correctly diagnosing hypertension was 0.26; the negative predictive value was 0.45. CONCLUSIONS: Our data suggest that the Vita-Stat is not only inconsistent but inaccurate in measuring blood pressure in the ambulatory patient and is, therefore, not appropriate to use as a monitoring device.

Blood Pressure Determination↗

PubMed1982

Ambulatory blood pressure monitoring in diabetic males: a method for detecting blood pressure elevations undisclosed by conventional methods.

Twenty-one diabetic males, ages 20 to 61 years (mean 48.4 +/- 10.5) and 14 healthy males, 22 to 59 years (mean 42.5 +/- 10.4) consented to participate in a study during which 24-h recordings of systolic and diastolic blood pressures, heart rates, and rhythm were obtained. The diabetic subjects were considered normotensive except for two patients, who had been observed to have rare insignificant elevations in blood pressure and were untreated. Diabetic subjects had a higher mean maximal systolic blood pressure (160.7 +/- 49.8 mmHg) than the normal controls (132.4 +/- 12.1 mmHg) (p less than 0.05). They also had a higher frequency (15.1%) of systolic blood pressure readings greater than or equal to 150 mmHg compared to normal men (0.2%) (p less than 0.01). The frequency of diastolic blood pressure readings greater than or equal to 90 mmHg was 22.1% in the former and 9.2% in the latter group (p less than 0.01). Of 21 diabetic males, 14 (66.7%) had systolic pressures greater than or equal to 150 mmHg, diastolic pressures greater than or equal to 100 mmHg, or both. In the normal men, 3 (21.4%) of the 14 had such pressures. Twenty-four hour monitoring of ambulatory blood pressures revealed elevations not detected by routine casual readings in patients with diabetes.

Adult↗

PubMed1990

The slope of the end-systolic pressure-volume relationship compared with the global end-systolic pressure-volume ratio in humans.

The slope of the end-systolic pressure-volume relationship (Emax), which is generated clinically by load manipulation, as well as the "absolute" peak systolic pressure end-systolic volume ratio (denoted as pressure-volume ratio), have been suggested as indices defining left ventricular function. This study represents an attempt to determine the relationship between these two indices by studying 20 patients (16 with coronary artery disease and 4 with normal coronary arteries) undergoing cardiac catheterization. Left ventriculography was performed three times in each patient: (1) in the control baseline state, (2) after rapid intravenous infusion of 250-300 cc of saline, and (3) after sublingual administration of 5 mg isosorbide dinitrate. Emax was approximated by linear regression using the peak left ventricular pressure (replacing end-systolic pressure) and the smallest left ventricular (end-systolic) volume for these three different loads. Acute ischemia with typical chest pain and ECG changes developed in 4 patients during saline loading. The pressure-volume ratio showed no change with load manipulation in patients who did not demonstrate ischemia. In the 4 patients who developed acute ischemia, the pressure-volume ratio dropped from 4.4 +/- 1.3 to 2.9 +/- 0.9 mmHg/ml (p less than 0.001). In all of the patients, the pressure-volume ratio, but not the Emax, correlated with the ejection fraction (r = 0.6; p less than 0.05). In addition, the Emax line demonstrated a markedly nonphysiological Vo. There was no correlation between Emax and pressure-volume ratio.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1983

Effects of increased systemic blood pressure on the tissue fluid pressure threshold of peripheral nerve.

This study was designed to evaluate the functional response of the median nerve at the wrist to various degrees of acute, local compression in hypertensive patients. After measuring resting tissue fluid pressure in the carpal tunnel of the nondominant hand of nine subjects (diastolic pressures of 90 mm Hg or greater), localized pressures of 50, 60, or 70 mm Hg were applied to the palmar aspect of the wrist. Motor and sensory latencies and amplitudes of the median nerve were evaluated before compression, during 30-240 min of compression, and during the postcompression recovery phase. Sensory responses were completely blocked at a threshold tissue fluid pressure of 60-70 mm Hg, measured by the wick catheter technique. This pressure threshold was greater than the 40-50 mm Hg previously found in normotensive subjects. The tissue pressure threshold of normotensive and hypertensive subjects was consistently 30 mm Hg below diastolic blood pressure (approximately 45 mm Hg below mean arterial blood pressure). These results support the concept that ischemia is the prime mechanism of conduction block in low pressure, nerve-compression syndromes.

Action Potentials↗

PubMed1984

The interrelationship between blood pressure, intramuscular pressure, and isometric endurance in fast and slow twitch skeletal muscle in the cat.

Two series of experiments were performed to examine the interrelationships between blood pressure, intramuscular pressure, muscle blood flow, and the endurance for isometric exercise in a fast (medial gastrocnemius) and a slow (soleus) twitch muscle of the cat. In the first series of experiments, the relationship between tension and intramuscular pressure was examined. It was found that intramuscular pressure was linearly related to tension in both muscles. However, at any proportion of the muscles maximum tension, the intramuscular pressure of the medial gastrocnemius muscle (the stronger of the muscles) was about twice that of the soleus. A second series of experiments was conducted in which blood pressure was increased above intramuscular pressure and the effect of blood pressure on isometric endurance was measured. The pressure of the perfusing blood of the cat's hind limb was adjusted to either 13.3, 26.6, or 39.9 kPa. It was found that increased perfusion of the muscle resulted in a dramatic increase in the endurance for contractions sustained at isometric tensions below 60% of the muscle's initial strength. In contrast, for contractions above this tension, the effect of increased perfusion was much less pronounced.

Animals↗

PubMed2002

Blood pressure control--effects on diabetic nephropathy progression: how low does blood pressure have to be?

Hypertension and diabetes are independent risk factors for both cardiovascular disease and renal complications. Coexistence of these comorbid conditions predisposes the patient to a much greater risk of progression to end-stage renal disease. Combined with the increased cardiovascular mortality, this has led to recent Joint National Committee-VI recommendations for the initiation of antihypertensive therapy for people with diabetes at a blood pressure of 130/85 mm Hg, a level lower than that recommended for the nondiabetic population. Results of a review of recently published investigations on the effects of blood pressure on diabetic nephropathy progression are presented in this article. This review finds evidence to support reducing the mean arterial blood pressure to levels below 95 mm Hg, a level that is even lower than the blood pressure of 130/80 mm Hg (mean arterial pressure of 97 mm Hg) recommended by the American Diabetes Association and National Kidney Foundation. The effect of blood pressure on renal disease progression is linear and appears to have no lower threshold for the benefits of blood pressure reduction on limiting nephropathy progression. The answer to the question of how low does blood pressure have to be to minimize the effects of blood pressure on diabetic nephropathy progression might be "the lower, the better."

Antihypertensive Agents↗

PubMed1992

Clinical value of blood pressure measurements: focus on ambulatory blood pressures.

Because clinic blood pressure values are compromised by 2 major limitations--the alerting reaction to clinic measurements and the spontaneous blood pressure variability--they have only a limited correlation with average 24-hour blood pressure values. Whether the latter should be employed routinely in substitution for, or in addition to, traditional blood pressure measurements has not yet been determined, however. To date, average 24-hour blood pressure values have been shown to correlate more closely than clinic blood pressure values with the organ damage of hypertension. A correlation with organ damage has been shown also for a number of blood pressure values within the 24 hours. Nevertheless, the clinical importance of 24-hour blood pressure and blood pressure variability has never been confirmed by prospective controlled studies. This information needs to be obtained before this approach is routinely employed in the clinical practice.

Ambulatory Care↗

PubMed1989

Clinical significance of elevated mean arterial blood pressure in second trimester and threshold increase in systolic or diastolic blood pressure during third trimester.

The purpose of this investigation was to determine the diagnostic value of an average mean arterial blood pressure in the second trimester of greater than or equal to 90 mm Hg and a threshold increase in diastolic blood pressure of greater than or equal to 15 mm Hg or in systolic blood pressure of greater than or equal to 30 mm Hg, on two occasions, 6 hours apart, in predicting preeclampsia. The study population consisted of 700 young normotensive primigravid women who were evaluated prospectively during pregnancy. Systolic and diastolic blood pressures were carefully measured at each prenatal visit, and the mean arterial blood pressure in the second trimester was calculated for each measurement. An average greater than 90 mm Hg was considered abnormal. One hundred thirty-seven patients had preeclampsia, for an overall incidence of 19.6%. An average greater than 90 mm Hg had a sensitivity of 8% and a positive predictive value of 23%. The respective values for a threshold increase of greater than 15 mm Hg in diastolic pressure were 39% and 32%. For a threshold increase of greater than 30 mm Hg in systolic pressure, values were 22% and 33%. The negative predictive values for all tests studied ranged between 81% and 85%. Neither a mean arterial blood pressure in the second trimester of greater than 90 mm Hg nor a threshold increase in systolic or diastolic blood pressure during the third trimester was significantly predictive of the development of preeclampsia.

Blood Pressure↗

PubMed1989

Urethral pressure variations diagnosed by multiple urethral pressure transducers. A common phenomenon in women suffering from urinary incontinence.

The prevalence of urethral pressure variations (variation of urethral pressure greater than 15 cm H2O) was investigated, with the use of a data-based multitransducer catheter, in female patients suffering from urinary incontinence. Urethral pressure variations were diagnosed in 45 (63%) of 71 patients. This prevalence was greater than in previous studies, possibly for methodological reasons; the urethral pressure was simultaneously measured by five urethral microtransducers, thereby registering all variations in maximal urethral pressure. The present method also showed that urethral pressure variations were simultaneously present in different urethral sites, but that the amplitude of variation differed between the different points of registration. In most cases, urethral pressure variations were already apparent at the start of urethrocystometry. Voluntary holding, in an effort to inhibit the desire to void, can cause these variations in urethral pressure. Hence urethral pressure variations may be a normal physiological phenomenon.

Female↗

PubMed1986

Urodynamic appraisal of vaginal versus rectal pressure recordings as indication of intra-abdominal pressure changes.

To compare intravaginal versus intrarectal pressure recordings as an indication of intra-abdominal pressure changes, simultaneous recording of the vaginal, bladder, and rectal pressures were obtained in 20 women. The transmitted pressure changes recorded from the inner and middle thirds of the vagina strongly correlated with the transmitted pressure changes recorded from the bladder (r = 0.99) when compared with the observed correlation between bladder and rectal pressure recordings (r = 0.91). The vaginal pressure recording is an easier and accurate alternative to intrarectal pressure recordings for approximating abdominal pressure changes during urodynamic testing.

Adult↗

PubMed1989

Reassessment of valve area determinations in mitral stenosis by the pressure half-time method: impact of left ventricular stiffness and peak diastolic pressure difference.

Estimation of the orifice area is of major importance in the timing of valve dilation or surgery in patients with mitral stenosis. Determination of the area has traditionally been accomplished at cardiac catheterization by the Gorlin equation. The valve area can also be estimated noninvasively with Doppler echocardiographic measurements of the pressure half-time, which is inversely proportional to the area. This method has gained widespread acceptance, but its accuracy has recently been questioned and factors other than reduction of orifice area appear to modify the pressure half-time. In the present study, the influence of left ventricular stiffness (defined as diastolic pressure rise per milliliter of mitral flow) and peak atrioventricular pressure difference on the pressure half-time was examined both in a hydraulic model and by review of data from 35 patients with mitral stenosis. Left ventricular stiffness less than 0.13 mm Hg/ml was considered normal. In the model study, the orifice area correlated only moderately with inverted pressure half-time (1/PHT) (r = 0.67). By multiple linear regression, inverted pressure half-time was shown to be dependent on valve area, chamber stiffness and peak pressure difference (R = 0.89), area and stiffness being most important (R = 0.85). In the clinical study, an increased ventricular stiffness was found in 22 of the 35 patients. The pressure half-time method overestimated the Gorlin-derived area by an average of 72% in these patients compared with only 10% in 13 patients with normal stiffness (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed2006

Effect of blood pressure instrument and cuff side on blood pressure reading in pregnant women in the lateral recumbent position.

BACKGROUND: Hydrostatic forces affect non-invasive blood pressure measurement in the lateral position. This study assessed the extent of this effect with the mercury column sphygmomanometer and Dinamap oscillometric instrument as well as different recommendations for comparing supine and lateral blood pressure measurements. METHOD: Thirty-two term pregnant women were studied in the antenatal clinic. Blood pressure was recorded from both arms in the right lateral and supine recumbent positions, using the sphygmomanometer and Dinamap. RESULTS: Blood pressure in the uppermost arm while lateral was lower than supine by a mean 10 mmHg or more. Systolic, mean and diastolic pressures in the dependent arm while lateral were higher than supine by a mean (SD) 3.1 (6.8)mmHg, 5.6 (6.8)mmHg, and 6.9 (8.7)mmHg using the sphygmomanometer and 3.8 (8.1)mmHg, 3.2 (7.1)mmHg, and 1.9 (5.3)mmHg using the Dinamap. Systolic, mean and diastolic pressure values calculated as the average taken from both arms in the lateral position were lower than supine by a mean (SD) 3.5 (7.5)mmHg, 3.9 (4.7) mmHg, and 4.1 (5.8)mmHg using the sphygmomanometer and 4.6 (6.0)mmHg, 4.9 (4.4)mmHg, and 4.8 (4.4)mmHg using the Dinamap. Corresponding blood pressure readings were always higher using the Dinamap than the sphygmomanometer. CONCLUSIONS: In normotensive non-labouring term pregnant women, the use of the dependent arm or an average blood pressure from both arms while in the lateral position will give a closer reading to supine blood pressure than the use of the uppermost arm. However, use of the dependent arm is simpler.

Adult↗

PubMed1979

Diastolic pressure-volume relations and distribution of pressure and fiber extension across the wall of a model left ventricle.

A model for left ventricular diastolic mechanics is formulated that takes into account noneligible wall thickness, incompressibility, finite deformation, nonlinear elastic effects, and the known fiber architecture of the ventricular wall. The model consists of a hollow cylindrical mass of muscle bound between two plates of negligible mass. The wall contains fiber elements that follow a helical course and carry only axial tension. The fiber angle (i.e., helical pitch) is constant along the length of each fiber but varies through the wall in accordance with the known distribution of fiber orientations in the canine left ventricle. To simplify the analysis and reduce the number of degrees of freedom, the anatomic distribution of fiber orientations is divided into a clockwise and counterclockwise system. The reference configuration for the model corresponds to a state in which, by hypothesis, the transmural pressure gradient is zero, the tension is zero for all fibers across the wall, and all fibers are assumed to have a sarcomere length of 1.9 micrometer. This choice of reference configuration is based on the empirical evidence that canine ventricles, fixed in a state of zero transmural pressure gradient and dissected, demonstrate sarcomere lengths between 1.9 and 2.0 micrometer in inner, middle, and outer wall layers, while isolated ventricular muscle bundles are observed to have zero resting tension when the sarcomere length ranges from 1.9 to 2.0 micrometer. An equation representing the global condition for equilibrium is derived and solved numerically. It is found that the model's pressure-volume relation is representative of diastolic filling in vivo over a wide range of filling pressures, and the calculated midwall sarcomere lengths in the model compare favorably with published experimental data. Subendocardial fibers are stretched beyond Lmax even at low filling pressures, i.e., 5 mm Hg, while fibers located between 60-80% of wall thickness extend minimally between 5 and 12 mm Hg. The hydrostatic pressure field within the wall is highly nonlinear. The pressure rises steeply in the subendocardial layers so that the net gain in pressure in the inner third of the wall is 85% of the filling pressure. It is demonstrated that these results are independent of heart size for a family of heart models that are scale models of each other. They are, however, critically dependent on the existence of longitudinally oriented fibers in the endocardial and epicardial regions of heart wall.

Animals↗