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Biomedical subjects

M H Alderman

Publications and source records attributed to M H Alderman.

At least 91 records · Page 5Linked to original sources
PubMed1994

Assessment of left ventricular function by the midwall fractional shortening/end-systolic stress relation in human hypertension.

OBJECTIVES: This study examined left ventricular performance in relatively unselected hypertensive patients by use of physiologically appropriate midwall shortening/end-systolic stress relations. BACKGROUND: Supranormal left ventricular function has been reported in hypertensive patients, possibly due to an artifact of mismatching endocardial rather than midwall fractional shortening to mean left ventricular end-systolic stress. METHODS: Samples of 474 hypertensive patients (150 women, 324 men) and 140 normal subjects (68 women, 72 men) were drawn from a large urban employed population. The inverse relations (p < 0.0001) of both echocardiographic endocardial and midwall fractional shortening to end-systolic stress in normal subjects were used to calculate the ratios of observed to predicted endocardial and midwall fractional shortening in hypertensive patients. Midwall shortening was calculated from an elliptic model, taking into account the epicardial migration of the midwall during systole. RESULTS: Use of midwall fractional shortening in hypertensive patients reduced the proportion of patients with function above the 95th percentile of normal from 22% to 4% (p < 0.0001) and fractional shortening as a percent of predicted from 107% (p < 0.001 vs. 100% in normotensive control subjects) to 95% (p < 0.0001; p < 0.001 vs. 101% in normotensive control subjects). Midwall shortening was below the 5th percentile of normal in 16% of hypertensive patients instead of 2% with endocardial shortening (p < 0.0001): They tended to be older than other hypertensive patients and had concentric left ventricular hypertrophy. Among hypertensive patients, those with concentric left ventricular hypertrophy or remodeling had reduced midwall shortening as a percent of predicted from end-systolic stress (p < 0.0001). CONCLUSIONS: Use of the physiologically more appropriate midwall shortening/end-systolic stress relation 1) markedly reduces the proportion of hypertensive subjects identified as having high endocardial left ventricular function; and 2) identifies a substantial subgroup of patients with reduced left ventricular function who have concentric geometry of the left ventricle, a pattern associated with high cardiovascular risk.

Adult↗
PubMed1994

Ethnicity and the relationship of sodium intake to blood pressure.

OBJECTIVE: To examine the impact of race on the relationship between sodium intake and blood pressure. METHODS: We examined the blood pressure levels and 24-h urinary sodium excretion of 808 (355 Black, 453 Caucasian) union members who participated in a workplace hypertension control program. The 808 study subjects, who met the criterion for accuracy of urine collection, included 627 untreated hypertensives (systolic blood pressure > or = 160 mmHg or diastolic blood pressure > or = 95 mmHg, or both) and 181 normotensives (blood pressure < 160/95 mmHg). RESULTS: In univariate analysis, the age-adjusted mean diastolic blood pressure levels of the Black subjects exceeded those of the Caucasian subjects at a significance level that was marginal for the male and very high for the female subjects. No differences were observed in mean systolic blood pressure between the Black and Caucasian subjects. Within each racial grouping, the subjects were grouped by sex-specific tertile of urinary sodium excretion in order to compare baseline characteristics and blood pressure levels. Small differences between the Black and Caucasian males in age-adjusted blood pressure within each urinary sodium excretion category were further diminished after adjusting for confounding factors. Significant differences between the Black and Caucasian females in age-adjusted diastolic blood pressure within each urinary sodium excretion group became non-significant when further adjusted for weight or body mass index, or both. These findings are in agreement with those observed in multiple linear regression models. CONCLUSION: In this socio-economically homogeneous group, when confounding factors are considered, Black and Caucasian subjects have similar blood pressure levels at the same level of 24-h urinary sodium excretion. Ethnicity itself was not found to influence the relationship between sodium intake and blood pressure.

Adult↗
PubMed1994

Relation of pulse pressure and blood pressure reduction to the incidence of myocardial infarction.

The prognostic value of pretreatment pulse pressure as a predictor of myocardial infarction and the relation of pulse pressure and in-treatment diastolic blood pressure reduction to myocardial infarction were investigated in a union-sponsored systematic hypertension control program. In a prospective study, 2207 hypertensive patients with a pretreatment systolic blood pressure greater than or equal to 160 mm Hg and/or diastolic pressure greater than or equal to 95 mm Hg grouped according to tertile of pulse pressure (PP1, < or = 46; PP2, 47 to 62; PP3, > or = 63 mm Hg) were further stratified by the degree of diastolic fall: large (L), > or = 18; moderate (M), 7 to 17; small (S), < or = 6 mm Hg. During an average follow-up of 5 years, 132 cardiovascular events (50 myocardial infarctions, 23 strokes) were observed. Myocardial infarction rates per 1000 person-years were positively related to pulse pressure (PP1, 3.5; PP2, 2.9; PP3, 7.5; PP3 versus PP1, P = .02). Wide pulse pressure was identified as a predictor of myocardial infarction (PP3 versus [PP1 + PP2]: relative risk [RR] = 2.2, 95% confidence interval [CI] = 1.2-4.1), controlling for other known risk factors by Cox regression. A curvilinear relation (resembling a J shape) between diastolic fall and myocardial infarction was observed in patients with the widest pulse pressure, PP3 (L, 9.5; M, 3.9; S, 11.2; L versus M: RR = 2.5, 95% CI = 1.0-6.2; S versus M: RR = 2.9, 95% CI = 1.1-8.0).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Relation of obesity and gender to left ventricular hypertrophy in normotensive and hypertensive adults.

Although it is recognized that both hypertension and obesity are associated with increased left ventricular mass, the relative impacts of obesity, arterial hypertension, and gender on the prevalence of ventricular hypertrophy remain uncertain. Accordingly, echocardiographic left ventricular mass normalized for height to the power of the allometric or growth relation between ventricular mass and height was compared in 164 normotensive subjects (85 men [24 obese] and 79 women [28 obese], aged 45 +/- 12 years) and 475 hypertensive patients (325 men [126 obese] and 150 women [85 obese], aged 54 +/- 10 years) from an adult employed population. Gender-specific upper normal limits were used to identify ventricular hypertrophy. Left ventricular mass/height 2.7 was higher in obese than normal-weight normotensive subjects (P < .004) independently of the level of blood pressure and identified a higher prevalence of hypertrophy (mainly eccentric) in obese than in normal-weight normotensive subjects (14% versus 5%, P < .04), a difference that was not detected by left ventricular mass/body surface area. Left ventricular mass/height identified hypertrophy in 52% of obese and 30% of normal-weight hypertensive patients (P < .0001) because of higher prevalences in obese than normal-weight patients of both eccentric (34% versus 20%) and concentric ventricular hypertrophy (18% versus 10%). The increase in left ventricular mass was independent of blood pressure values in obese normotensive women (but not men), and the prevalence of supranormal left ventricular mass/height 2.7 was even higher in hypertensive obese women (58%) than men (49%).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

The determinants of hypertension awareness, treatment, and control in an insured population.

OBJECTIVES: The purpose of the study was to identify the determinants of awareness, treatment, and control of hypertension in a population with full access to medical care. METHODS: Unionized New York City health care workers (n = 1394) with comprehensive medical insurance were screened for hypertension. Union records documenting all physician visits and prescription medications for the year before screening provided the opportunity to relate patterns of treatment to blood pressure outcomes. RESULTS: Of the 409 employees found to have hypertension, 289 (71%) were aware of their condition and 201 (49%) had been treated, but only 51 (12%) had their blood pressure controlled at the recommended level (< 140/90 mm Hg). In a logistic regression model, the only variable of treatment associated with control was days of antihypertensive medication. The total number of physician visits was not associated with control. CONCLUSIONS: These findings demonstrate that in conventional community settings, even in the absence of financial barriers, treatment for hypertension continues to be characterized by poor outcomes. Improving access to primary care, without changes in the nature of that care, may not substantially improve blood pressure control.

Aged↗
PubMed1994

Response to the captopril test is dependent on baseline renin profile.

OBJECTIVE: To determine prospectively the relationship between the renin-sodium profile and the renin response to captopril challenge in patients with essential hypertension. DESIGN: A standard captopril test was performed in 108 uncomplicated, untreated hypertensive subjects with normal renal function and urinary sodium excretion in the range 50-240 mmol/day. The subjects were selected from a working population with a low expected prevalence of renovascular disease. METHOD: The captopril test was considered positive if the captopril-induced rise in plasma renin activity met all three criteria established by Müller et al. Patients with a positive test and those meeting only one or two of the three criteria were further investigated for renovascular hypertension by measuring renal venous renins and by digital subtraction intravenous angiography. Renin responses were analyzed according to baseline renin-sodium profile. RESULTS: Nine of 108 subjects had a false-positive captopril test result. Among the subjects with a low or normal renin-sodium profile, 1% (one of 82) had a false-positive result. In contrast, false-positive results were seen in 31% (eight of 26) of high-renin subjects. False-positive test results were not related to urinary sodium excretion or to excessive decrease in blood pressure. The magnitude of the renin response to captopril was strongly and directly related to the baseline plasma renin activity. CONCLUSION: An exaggerated renin response to captopril challenge is common in patients with high-renin essential hypertension. Therefore, in a population with a low probability of renovascular hypertension, caution is recommended in interpreting a positive test result in patients with a high baseline renin.

Adult↗
PubMed1993

Blood pressure management: individualized treatment based on absolute risk and the potential for benefit.

Clinical practice often conflicts with epidemiologic evidence in the management of blood pressure. Antihypertensive therapy is generally prescribed if blood pressure exceeds some arbitrary level, thus committing many persons with minimal cardiovascular risk to long-term drug therapy. By contrast, below that level, regardless of cardiovascular risk, blood pressure reduction is rarely sought. Epidemiologic data, however, consistently show a continuous, positive, linear relationship of the height of both systolic and diastolic blood pressure with the incidence of stroke and heart attack. No threshold level distinguishes those who will have a cardiovascular event from those who will not. In fact, most heart attacks and many strokes occur among persons with "normal" blood pressures. Observational experience suggests that benefit could be obtained from universal blood pressure reduction of even a few millimeters of mercury. This public health strategy can be augmented by identifying those individuals, at every level of blood pressure, whose risk for cardiovascular disease justifies the cost of pharmacologic intervention. Antihypertensive drug therapy will be most efficient and effective if directed at those who, by virtue of their constellation of risk factors or evidence of preclinical vascular disease, are likely to have a heart attack or stroke. The resulting redirection of clinical resources will spare many hypertensive persons whose absolute risk for a cardiovascular event is small, from life-long treatment. At the same time, other persons, currently classified as normotensive, will become candidates for blood pressure reduction because their cardiovascular risk is high.

Antihypertensive Agents↗
PubMed1993

Intracellular and extracellular magnesium depletion in type 2 (non-insulin-dependent) diabetes mellitus.

To investigate alterations of magnesium metabolism in Type 2 (non-insulin-dependent) diabetes mellitus, we utilized a new magnesium-specific selective ion electrode apparatus to measure serum ionized magnesium (Mg-io) in fasting subjects with and without Type 2 diabetes, and compared these values to levels of serum total magnesium, and of intracellular free magnesium (Mgi) analysed by 31P-NMR spectroscopy. Both Mg-io (0.630 +/- 0.008 vs 0.552 +/- 0.008 mmol/l, p < 0.001) and Mgi (223.3 +/- 8.3 vs 184 +/- 13.7 mmol/l, p < 0.001), but not serum total magnesium, were significantly reduced in Type 2 diabetes compared with non-diabetic control subjects. Furthermore, a close relationship was observed between serum Mg-io and Mgi (r = 0.728, p < 0.001). We suggest that magnesium deficiency, both extracellular and intracellular, is a characteristic of chronic stable mild Type 2 diabetes, and as such, may predispose to the excess cardiovascular morbidity of the diabetic state. Furthermore, by more adequately reflecting cellular magnesium metabolism than total serum magnesium levels, Mg-io measurements may provide a more readily available tool than has heretofore been available to analyse magnesium metabolism in a variety of diseases.

Blood Glucose↗
PubMed1993

A review of the Joint National Committee on Detection, Evaluation, and Treatment of High Blood Pressure. The Fifth Report, 1993.

JNC-V is a comprehensive document that also contains a variety of specific information about drug actions, interactions, and specific indications and contraindications for each class of antihypertensive drugs. In addition, there are recommendations regarding patient evaluation and follow-up. Individual sections deal with blood pressure management in special situations and in different populations. References are included to support the assertions made and to permit further assessment by the reader of some of the evidence that the committee used to reach its conclusions. In sum, the new Joint National Committee Report continues a tradition of bringing to the profession and the public at large the current best judgment regarding practice that is constantly in evolution. It is not the ultimate document, but another step toward a goal that remains the same. That goal is to reduce cardiovascular morbidity and mortality, improve and extend life, and to achieve these objectives in the least intrusive and most efficient way possible.

Algorithms↗
PubMed1993

Role of preclinical cardiovascular disease in the evolution from risk factor exposure to development of morbid events.

Conventional risk factors (especially high arterial pressure, elevated cholesterol and glucose levels, and cigarette smoking) are useful predictors of morbid atherosclerotic and hypertensive events, and their control variably reduces the incidence of events. However, both the ability to predict risk and the ability to reduce it by modification of established risk factors are limited. These limitations occur in part because the progression from risk factor exposure to morbid events depends on the variable likelihood that individuals exposed to the same risk factors will progress through two stages: the development of asymptomatic or "preclinical" anatomic and functional cardiovascular disease in response to standard risk factors and other variables, and the precipitation of morbid events by progression of preclinical disease or by the action of additional "triggering" mechanisms in the presence of preclinical disease. Advances in diagnostic methodology now make possible accurate noninvasive detection in many asymptomatic individuals of preclinical disease such as left ventricular hypertrophy, carotid atherosclerosis, and renal dysfunction. Progress in elucidating stimuli to left ventricular hypertrophy and systemic atherosclerosis suggests that focusing research separately on these two stages of disease evolution is a fruitful strategy. The closer relation of measures of preclinical disease than risk factors with the subsequent risk of complications indicates that their detection improves clinical risk stratification. However, critical testing of whether clinical outcome is improved or treatment cost is lowered by basing antihypertensive or antihyperlipidemic treatment decisions in part on the presence of preclinical cardiovascular disease is needed before this strategy is adopted on a widespread scale.

Adult↗
PubMed1993

Enhancing athletic injury rehabilitation adherence.

Contemporary sports medicine literature has begun to address more centrally the idea that treatment adherence is a complex issue. Not only must certified athletic trainers (ATCs) possess knowledge about injuries and subsequent rehabilitation protocols, they also must be able to deliver essential services in a manner that predisposes treatment success. Effective treatment of athletic injuries necessitates consideration of various psychosocial factors shown to enhance rehabilitation adherence. Detailed explanations of several important ATC-athlete interaction patterns and motivational strategies are offered.

Journal Article↗
PubMed1992

Left ventricular mass and body size in normotensive children and adults: assessment of allometric relations and impact of overweight.

OBJECTIVES: This study was designed to determine the most appropriate method to normalize left ventricular mass for body size. BACKGROUND: Left ventricular mass has been normalized for body weight, surface area or height in experimental and clinical studies, but it is uncertain which of these approaches is most appropriate. METHODS: Three normotensive population samples--in New York City (127 adults), Naples, Italy (114 adults) and Cincinnati, Ohio (444 infants to young adults)--were studied by echocardiography. Relations of left ventricular mass to body size were similar in all normal weight groups, as assessed by linear and nonlinear regression analysis, and results were pooled (n = 611). RESULTS: Left ventricular mass was related to body weight to the first power (r = 0.88), to body surface area to the 1.5 power (r = 0.88) and to height to the 2.7 power (r = 0.84), consistent with expected allometric (growth) relations between variables with linear (height), second-power (body surface area) and volumetric (left ventricular mass and body weight) dimensions. Strong residual relations of left ventricular mass/body surface area to body surface area (r = 0.54) and of ventricular mass/height to height (r = 0.72) were markedly reduced by normalization of ventricular mass for height2.7 and body surface area1.5. The variability among subjects of ventricular mass was also reduced (p < 0.01 to p < 0.002) by normalization for body weight, body surface area, body surface area1.5 or height2.7 but not for height. In 20% of adults who were overweight, ventricular mass was 14% higher (p < 0.001) than ideal mass predicted from observed height and ideal weight; this increase was identified as 14% by left ventricular mass/height2.7 and 9% by ventricular mass/height, whereas indexation for body surface area, body surface area1.5 and body weight erroneously identified left ventricular mass as reduced in overweight adults. CONCLUSIONS: Normalizations of left ventricular mass for height or body surface area introduce artifactual relations of indexed ventricular mass to body size and errors in estimating the impact of overweight. These problems are avoided and variability among normal subjects is reduced by using left ventricular mass/height2.7. Simple nomograms of the normal relation between height and left ventricular mass allow detection of ventricular hypertrophy in children and adults.

Adult↗
PubMed1992

Prevention of myocardial infarction.

Despite substantial progress in cardiovascular disease prevention, stroke and myocardial infarction remain the leading causes of death throughout the industrialized world. Treatment of high blood pressure, while contributing importantly to this progress, remains inefficient and less than optimally effective, particularly in regard to coronary artery disease events. Therapeutic intervention in the renin-angiotensin system offers promise of progress on both these fronts. Renin-sodium profiles have been shown to permit prognostic stratification of otherwise indistinguishable hypertensive patients. Indeed, low renin subjects, without other cardiovascular risk factors, have a particularly favorable prognosis. Now, the pharmacologic ability to mute the pathologic effects of angiotensin II also offers the genuine possibility that the cardioprotective value of antihypertensive therapy may be significantly improved.

Humans↗
PubMed1992

Left ventricular hypertrophy in black and white hypertensives. Standard electrocardiographic criteria overestimate racial differences in prevalence.

OBJECTIVE: To assess racial differences in the accuracy of standard electrocardiographic (ECG) criteria in the diagnosis of left ventricular hypertrophy (LVH). DESIGN: The sensitivity and specificity of standard ECG criteria were compared in blacks and whites using echocardiographic LVH as the reference standard. SETTING: Eight worksite-based hypertension clinics in New York, NY. PATIENTS: A sample of 122 black and 148 white hypertensive patients. RESULTS: The prevalence of ECG-LVH was two to six times higher in blacks than in whites, depending on the criteria used (range, 6% to 24% in blacks vs 1% to 7% in whites; P = .0005 to .19 for black-white comparisons). The difference in prevalence of echocardiographic LVH [corrected], however, was less striking and did not attain statistical significance (26% in blacks and 20% in whites; P greater than .2). The sensitivity of the ECG was low (range, 3% to 17%) and did not differ significantly between the two races for any of the conventional criteria; specificity, however, was lower in blacks for all criteria (range, 73% to 94% vs 95% to 100% for whites; P = .0001 to .09). The predictive value of a positive ECG was consistently, although not significantly, lower in the black subjects. Black race was the strongest independent predictor of decreased ECG specificity in multiple logistic regression analysis that also considered age, gender, body mass index, left ventricular mass index, and smoking. CONCLUSIONS: Commonly used ECG criteria for the detection of LVH have a poor sensitivity in both black and white hypertensives and a lower specificity in blacks than in whites; this may lead to a greater number of false-positive diagnoses in black patients, as well as to an overestimation of black-white difference in LVH prevalence.

Black People↗