ISSN:0194-911X    

出版商:OVID    

年代:1989

数据来源: OVID

ISSN:0194-911X    

出版商:OVID    

年代:1989

数据来源: OVID

ISSN:0194-911X    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

To determine the effect of race on cardiovascular disease occurrence among treated hypertensive patients, the experience of 1,807 black and 2,962 white hypertensive patients who entered a union/management-sponsored, worksite-based treatment program (1973–1985), was evaluated. Participants had similar socioeconomic profiles, equal access to health benefits, and received standard treatment. Median duration of observation was 42 months. Blacks had 48, and whites 129, of the 177 morbid (strokes and heart attacks) or mortal cardiovascular disease outcomes. At baseline, blacks had more electrocardiographic abnormalities (32% vs. 19%,p< 0.0001), lower mean cholesterol (218 vs. 230 mg%,p< 0.001), smoked more (35% vs. 30%,p< 0.001), and were less likely to be treated for hypertension before entering the program (53% vs. 58%,p< 0.01) than whites. They were also more likely than whites to belong to unions employing less skilled workers (p< 0.0001). Overall, all-cause mortality rates between the races were similar. However, total cardiovascular disease morbidity and mortality rates were 10.5 (whites) and 6.4 (blacks) per 1,000 person years (p< 0.005); the difference was largely explained by higher myocardial infarction rates among older (55 years or older) white men (15.6 vs. 7.5,p< 0.05). That advantage was not present amongst younger black persons. In fact, blacks lost more years of life before age 65 (102 vs. 64 years/1,000 persons,p< 0.025). In a Cox proportional hazards regression analysis, an interaction term of age and race, gender, baseline smoking status, prior treatment status, and electrocardiogram abnormality were strongly predictive of cardiovascular disease morbidity and mortality. Prior history of cardiovascular disease, cholesterol, and body mass index were less significant predictors, but union status was not. These findings, while reflecting the special concern of risk of cardiovascular disease for young blacks, suggested that, at similar starting blood pressure levels, blacks, when given equal access to the same treatment, will achieve similar, overall blood pressure declines and experience a lower incidence of cardiovascular disease than whites.

ISSN:0194-911X    

出版商:OVID    

年代:1989

数据来源: OVID

ISSN:0194-911X    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

Four remote population samples (Yanomamo and Xingu Indians of Brazil and rural populations in Kenya and Papua New Guinea) had the lowest average blood pressures among all 52 populations studied in INTERSALT, an international cooperative investigation of electrolytes and blood pressure. Average systolic blood pressure was 103 versus 120 mm Hg in the remaining INTERSALT centers; diastolic blood pressure in these four population samples averaged 63 versus 74 mm Hg in the 48 other centers. There was little or no upward slope of blood pressure with age; hypertension was present in only 5% of the rural Kenyan sample and virtually absent in the other three centers. Also in marked contrast with the rest of the centers was level of daily salt intake, as estimated by 24-hour urinary sodium excretion. Median salt intake ranged from under 1 g to 3 g daily versus more than 9 g in the rest of INTERSALT populations. Average body weight was also low in these four centers, with no or low average alcohol intake, again unlike the other centers. The association within these four centers between the above variables and blood pressure was low, possibly reflecting their limited variability. While several other INTERSALT centers also had low average body weight or low prevalence of alcohol drinking, when this was accompanied by much higher salt intake (7–12 g salt or 120–210 mmol sodium daily), hypertension prevalence ranged from 8% to 19%. These findings confirm previous reports that in populations with a low salt intake, there is little or no hypertension or rise of blood pressure with age. While the contributory role of other characteristics of these populations must also be considered, the results are consistent with the view that a certain minimum salt intake is essential for rise in blood pressure with age in adults and a high frequency of hypertension in populations.

ISSN:0194-911X    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

Renovascular hypertension is a potentially curable form of high blood pressure. However, it is unclear how best to select patients who are likely to have renovascular hypertension, what diagnostic strategy to use in these selected patients, and how to predict the hemodynamic significance of a renal artery stenosis. We determined the prevalence of renovascular hypertension in adults who exhibited suggestive clinical features. In these clinically selected patients, we then determined the test characteristics of various diagnostic and potential screening tests. Renovascular hypertension was diagnosed if correction of renal artery stenosis resulted in decreased blood pressure. Of the 66 hypertensive adults evaluated, 11 (16.7%) had renovascular hypertension. Captopril-stimulated peripheral renln activity detected renovascular hypertension with 73% sensitivity, 72% specificity, 38% positive predictive value, and 92% negative predictive value. Less optimal combinations of sensitivity and specificity were found for differential glomerular filtration rate renography, differential effective renal plasma flow renography, and selective renal vein renin ratios, each performed after a single dose of captopril. Intravenous digital subtraction renal angktgraphy detected all patients with renovascular hypertension and was normal in 71% of patients with essential hypertension. To evaluate potential screening tests for renovascular hypertension, we calculated predictive values applied to a low prevalence population. If the observed sensitivities and specificities apply to a population with 5% prevalence of renovascular hypertension, captopril-stimulated peripheral renin would have a positive predictive value of 12% and a negative predictive value of 98%. In 16 patients with known renal artery stenosis, neither the captopril-stimulated renal vein renin ratio nor captopril-stimulated differential renography accurately predicted blood pressure response to correction of the stenosis. We conclude that clinical criteria can identify a subgroup with 16.7% prevalence of renovascular hypertension. In this high prevalence group, intravenous digital subtraction renal angiography will identify virtually all patients with renovascular hypertension, and a normal study will be sufficient to exclude renovascular hypertension. In unselected hypertensive patients, screening with captopril-stimulated peripheral renin activity may be the most useful and efficient procedure for identification of patients with renovascular hypertension. Functional tests do not accurately predict the hemodynamic significance of a renal artery stenosis.

ISSN:0194-911X    

出版商:OVID    

年代:1989

数据来源: OVID

ISSN:0194-911X    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

To ascertain whether small shifts in plasma atrial natriuretic factor (ANF) exerted biological effects in hypertension, we studied the renal, hemodynamic, and hormonal effects of ANF [human ANF-(99–126)] infused at a dose (0.75 pmol/kg/min for 3 hours) that would induce changes in plasma ANF confined to the normal, resting range, in a group of six young men with uncomplicated, mild essential hypertension. During ANF infusions, the patients excreted 11.8±2.0 mmol (mean±SEM) sodium more than during the time-matched placebo phase natriuresis (p< 0.001, mean increase of 53% above placebo values). Urinary excretion of cyclic guanosine monophosphate rose to more than double (212%,p< 0.001) placebo values. Plasma renin activity (0.4±0.05 vs. 0.9±0.12 nmol/l/hr,p< 0.0001) and aldosterone concentrations (102±4 vs. 184±47 pmol/l,p< 0.05) were clearly suppressed during administration of ANF. Plasma norepinephrine also fell significantly below placebo values (268±17 vs. 439±35 pg/ml,p< 0.05). Urine volume, the excretion of electrolytes other than sodium, hematocrit, effective renal plasma flow, glomerular filtration rate, and filtration fraction were unaffected by ANF. Similarly, plasma concentrations of epinephrine, arginine vasopressin, adrenocorticotropic hormone, and cortisol were unchanged. Blood pressure and heart rate were unchanged. Minor perturbations in plasma ANF concentrations exert clear biological effects in patients with mild essential hypertension. These data suggest that such minor shifts in plasma ANF are of physiological relevance in mild hypertension and probably contribute to volume homeostasis in this condition.

ISSN:0194-911X    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

To investigate the possible role of body fluid volume or the renin-angiotensin system in the maintenance of high blood pressure in chronic one-kidney, one clip (1K1C) hypertension, we studied whether blood pressure remained high after removal of the clip while the body fluid volume was kept constant or when angiotensin II (Ang II) was infused in conscious 1K1C rats. Blood pressure fell 58 ±13 mm Hg in 1K1C rats after removal of the clip. When body fluid volume was kept at the same level as before “unclipping,” blood pressure fell only 9±2 mm Hg after removal of the clip; if body fluid volume was then allowed to decrease, blood pressure fell an additional 55 ±8 mm Hg. When Ang U was infused after removal of the clip, blood pressure fell 26±7 mm Hg despite the fact that plasma Ang II increased to nonphysiological concentrations (1,161 ±353 pg/ml). After Ang II infusion was stopped, blood pressure fell an additional 44 ±13 mm Hg. When Ang II was infused and body fluid volume kept constant, blood pressure still did not change after removal of the clip, although plasma Ang II concentrations increased to nonphysiological levels (618±98 pg/ml). After the Ang U infusion was discontinued and the body fluid volume was no longer kept constant, blood pressure fell 78 ±9 mm Hg. These data further support the hypothesis that a volume factor, not the renin-angiotensin system, is important in the maintenance of high blood pressure in 1K1C hypertension.

ISSN:0194-911X    

出版商:OVID    

年代:1989

数据来源: OVID